1296
Dielectric Interface
OPERATING MANUAL
Solartron
a division of Solartron Group Ltd
Victoria Road, Farnborough,
Hampshire GU14 7PW. UK.
Issue BE : Nov 1999
Solartron Part No. : 12966001
1999
Solartron
Victoria Road, Farnborough
Hampshire, GU14 7PW England
Telephone: +44 (0)1252 376666
Fax: +44 (0)1252 544981
Solartron
964 Marcon Blvd., Suite 200
Allentown, PA 18103, USA
Telephone: +1 610-264-5034
Fax: +1 610-264-5329
Solartron
37 Rue du Saule Trapu
91882 MASSY, Cedex
France
Telephone: +33 (0)1 69 53 63 53
Fax: +33 (0)1 60 13 37 06
Solartron
Beijing Liaison Office
Room 327 Ya Mao Building
No. 16, Bei Tu Chen Xi Road
Beijing 100101, PR China
Telephone: +86 10-6238 1199 ext 2327
Fax: +86 10-6238 4687
Email: solartron@solartron.com
Web: http://www.solartron.com
For details of our agents in other countries, please contact our Farnborough, UK, office.
Solartron pursues a policy of continuous development and product improvement.
The specification in this document may therefore be changed without notice.
Dielectric
Interface
IMP DLL1296
Driver
for Windows
3.1
Programmer’s
Guide
Operating Manual
Contents
Chapter 1
Introduction
1
What the 1296 Does
2
PC System Requirements
3
The 1296 Accessories
4
Installing the 1296
5
Using the 1296
6
1296 Information Available
7
Technical Support
Chapter 2
Installing the 1296
1
Hardware Installation
2
Software Installation
3
Initial Checkout
Chapter 3
Setting Up and Running an Experiment
1
Using the 1296
2
Defining an Instrument Set-up
3
Defining an Experiment
4
Defining a Sample
5
Setting Up a Measurement
6
Using Stored Set-Ups
Chapter 4
Displaying and Printing Graphs
1
Setting Up and Displaying a Graph
2
Using the Graph Facilities
3
Printing a Graph
Continued overleaf.
JWS / 1296 Op Man / Issue BB
Contents
1
Chapter 5
1
Exporting a Graph
2
Exporting the Measurement Data
Chapter 6
2
Contents
Exporting Graphs and Measurement Data
Using the Measurement Batch Facility
1
Introduction
2
Procedure
Appendix A
1296 Specification
Appendix B
1296 Measurement Term Definitions
Appendix C
Temperature Controller Set-Up Files
Appendix D
1296 Sample Holders
Appendix E
129604S Software for HP4192
JWS / 1296 Op Man / Issue BB
Solartron
a division of Solartron Group Ltd.
Victoria Road, Farnborough
Hampshire GU14 7PW England
Tel +44 (0) 1252 376666
Fax +44 (0) 1252 543854
DECLARATION OF CONFORMITY
The directives covered by this declaration
73/23/EEC
Low voltage Equipment Directive, amended by 93/68/EEC
89/336/EEC
Electromagnetic Compatibility Directive, amended by 92/31/EEC & 93/68/EEC
Product(s)
1296A Dielectric Interface
Basis on which conformity is being declared
The product(s) identified above comply with the requirements of the EU directives by meeting the
following standards:
EN50081-1:1992
Electromagnetic Compatibility - Generic Emission Standard
Part 1: Residential, commercial and light industry.
EN50082-1:1992
Electromagnetic Compatibility - Generic Immunity Standard
Part 1: Residential, commercial and light industry.
EN61010-1:1993
Safety requirements for electrical equipment for measurement, control and
laboratory use, including amendment A2:1995.
Accordingly the CE mark has been applied to this product.
Signed
For and on behalf of Solartron, a division of Solartron Group Limited
CERTIFICATE
No. FM1709
Authority:
Engineering Manager
Date:
August 1997
REGISTERED IN ENGLAND No.2852989. REGISTERED OFFICE: BYRON HOUSE, CAMBRIDGE BUSINESS PARK, CAMBRIDGE, CB4 4WZ
Approved to BS EN ISO 9001:1994 and BS EN 123000, MOD Registered Company
A Roxboro Group company
CALIBRATION
Nos. 0011 & 0099
GENERAL SAFETY PRECAUTIONS
The equipment described in this manual accords with BS EN61010 "Safety
requirements for electrical equipment for measurement, control and
laboratory use", and is supplied in a safe condition. To avoid injury to an
operator or service technician the safety precautions given below, and
throughout the manual, must be strictly adhered to, whenever the
equipment is operated, serviced or repaired. For specific safety details,
please refer to the relevant sections within the manual.
The equipment is designed solely for electronic measurement and should
be used for no other purpose. Solartron accept no responsibility for
accidents or damage resulting from any failure to comply with these
precautions.
GROUNDING
To minimize the hazard of electrical shock it is essential that the
equipment is connected to a protective ground whenever the power
supply, measurement or control circuits are connected, even if the
equipment is switched off.
Where mains power supply units are used, the protective earth (E)
terminal must be connected to the mains installation earth. The ground
connection must have a current rating of 25A.
AC SUPPLY VOLTAGE
Never operate the equipment from a line voltage or frequency in excess of
that specified. Otherwise, the insulation of internal components may
break down and cause excessive leakage currents.
FUSES
Before switching on the equipment check that the fuses accessible from
the exterior of the equipment are of the correct rating. The rating of the ac
line fuse must accord with the value stated in the Specification. (The
correct value for the ac supply fuse is also inscribed on the rear panel of
the instrument, near the ac supply connector.)
Should any fuse continually blow, do not insert a fuse of a higher rating.
Switch the equipment off, clearly label it "unserviceable" and inform a
service technician.
EXPLOSIVE ATMOSPHERES
NEVER OPERATE the equipment, or any sensors connected to the
equipment, in a potentially explosive atmosphere. It is NOT intrinsically
safe and could possibly cause an explosion.
Continued overleaf.
SAFETY PRECAUTIONS (continued from previous page)
SAFETY SYMBOLS
For the guidance and protection of the user, the following safety symbols
appear on the equipment:
SYMBOL
MEANING
!
Refer to operating manual for detailed instructions of use.
In particular, note the maximum voltages permissible at
the input sockets, as detailed in the Specification.
Hazardous voltages.
NOTES, CAUTIONS AND WARNINGS
For the guidance and protection of the user, Notes, Cautions and
Warnings appear, where necessary, in the manual. The significance of
these is as follows:
Note
Highlights important information for the reader’s special
attention.
Caution
Guides the reader in avoiding damage to the equipment.
Warning Guides the reader in avoiding a hazard that could cause injury
or death.
AVOID UNSAFE EQUIPMENT
The equipment may be unsafe if any of the following statements apply:
•
•
•
•
Equipment shows visible damage.
Equipment has failed to perform an intended operation.
Equipment has been subjected to prolonged storage under
unfavourable conditions.
Equipment has been subjected to severe physical stress.
If in any doubt as to the serviceability of the equipment, don’t use it. Get it
properly checked out by a qualified service technician.
LIVE CONDUCTORS
When the equipment is connected to its measurement inputs or supply,
the opening of covers or removal of parts could expose live conductors.
The equipment must be disconnected from all power and signal sources
before it is opened for any adjustment, replacement, maintenance or
repair. Adjustments, maintenance or repair, must be done only by
qualified personnel, who should refer to the Service Manual.
EQUIPMENT MODIFICATION
To avoid introducing safety hazards, never install non-standard parts in
the equipment, or make any unauthorized modification. To maintain
safety, always return the equipment to Solartron for service and repair.
1
Introduction: 1296 Dielectric Interface
Contents
1
WHAT THE 1296 DOES ........................................................................................................ 1-3
1.1
1296 HARDWARE FUNCTIONS ................................................................................. 1-3
1.2
1296 SOFTWARE FUNCTIONS .................................................................................. 1-3
2
PC SYSTEM REQUIREMENTS ............................................................................................. 1-3
3
THE 1296 ACCESSORIES .................................................................................................... 1-4
3.1
Sample holders ............................................................................................................ 1-4
4
INSTALLING THE 1296 ......................................................................................................... 1-4
5
USING THE 1296 ................................................................................................................... 1-4
6
1296 INFORMATION AVAILABLE........................................................................................ 1-5
7
TECHNICAL SUPPORT ........................................................................................................ 1-5
JWS / 1296 Operating Manual / Issue BB
Introduction: 1296 Dielectric Interface
1-1
1-2
Introduction: 1296 Dielectric Interface
JWS / 1296 Operating Manual / Issue BB
1
WHAT THE 1296 DOES
The 1296 Dielectric Interface is a development of the Chelsea Dielectric Interface.
It is used in conjunction with a Solartron Frequency Response Analyser (1260,
1255, 1253, or 1250) and extends the measurement capabilities of the FRA to
address a wide range of materials testing. 1296 can also be used with Hewlett
Packard’s HP4192 FRA - see Appendix E for details.
1.1
1296 HARDWARE FUNCTIONS
The 1296 is designed for control by a PC. The PC communicates with the 1296,
the FRA, and any other instruments in the system, via the GPIB. The system can
also include an ac amplifier, a dc bias generator and a temperature controller.
The basic function of the 1296 hardware is to extend the current measurement
range of the FRA downwards, from 6µA to 100fA, thus enabling the
measurement of very high impedance. In combination with the software it also
gives additional accuracy to capacitance measurement by enabling the sample
capacitance to be compared with high quality internal or external reference
capacitors.
1.2
1296 SOFTWARE FUNCTIONS
The PC software for the 1296 is a Microsoft Windows based package, designed
to run with Windows 3.1, ’95 and NT4.
The windows interface provided by the 1296 software offers a simple and
effective way of configuring the 1296 system for sample measurement. Once the
sample data has been obtained, other windows entries enable you to display the
data in graphical form, or to export the data, in its original form or as a graph
image, to other windows-based display facilities. Data is also saved to disk, for
later recall and analysis.
Sample measurement configurations can be saved on disk, and reloaded for
later use. A batch facility allows several such configurations to be loaded and
run to conduct a series of experiments. The batch configuration can include
executable files to control external equipment, such as a sample selector.
2
PC SYSTEM REQUIREMENTS
The minimum requirement for the PC that is to run the 1296 software is:
•
a 486 processor and 8Mbytes RAM,
•
5Mbytes of free disk space.
•
a National Instruments or CEC interface card for the GPIB.
JWS / 1296 Operating Manual / Issue BB
Introduction: 1296 Dielectric Interface
1-3
3
THE 1296 ACCESSORIES
The following accessories are provided as part of the 1296 product:
3.1
•
a set of software disks,
•
a 12961 Dielectric Reference Module,
•
four 0.5 metre BNC leads,
•
an ac power lead.
Sample holders
The 1296 2A sample holder and associated electrode kits (1296 3A and 1296 4A)
are available for use with both solid and liquids. More details are given in
Appendix D.
4
INSTALLING THE 1296
The installation of the 1296 hardware and software is described in Chapter 2 of
this manual.
The hardware installation consists of setting up, where necessary, the GPIB
addresses of the instruments used in the 1296 system and cabling the
instruments together.
The software installation consists of loading one or more floppy disks and
following the on-screen instructions.
5
USING THE 1296
The use of the 1296 is described in Chapters 3 through 6 of this manual. In
essence, the procedure is:
1. Define the instrument set-up. (See Chap. 3, Sect. 2.) This tells the 1296
software which instruments you are using, and their GPIB addresses.
2. Define the experiment. (See Chap. 3, Sect. 3.) Here you define the
experiment parameters, for example: the frequency and level of the ac
source, and the dc bias. You can set up a single sweep, of the frequency
value for example, or you if you wish can set up several nested sweeps.
3. Define the sample. (See Chap. 3, Sect. 4.) Here you enter the information
that enables the 1296 to compute the relative permittivity of the sample (or
"cell") to be measured. The information you enter can be either the cell
dimensions or the empty cell capacitance.
1-4
Introduction: 1296 Dielectric Interface
JWS / 1296 Operating Manual / Issue BB
4. Define the measurement set-up. (See Chap. 3, Sect. 5.) Here you select the
measurement method, Normal or Reference, and the integration to be used
by the FRA. With the Normal method the sample capacitance is measured
directly. The Reference method involves two measurements, one of the
sample capacitance and one of a reference capacitor of comparable value: a
comparison technique is then used to compute the true capacitance of the
sample.
5. Tell the 1296 to start. (See Chap. 3, Sect. 1.)
6. When data has been measured you can:
a. Display the data as a graph, and print it (see Chap. 4),
b. Export the data, directly or as a graph image, to other windows facilities
(see Chap. 5).
6
1296 INFORMATION AVAILABLE
The following sources of information are readily available for the 1296:
7
•
The 1296 Operating Manual.
•
The 1296 On-line Help Text.
TECHNICAL SUPPORT
Should you have a problem with your 1296 system, that can not be resolved by
recourse to the information listed above, then please contact the Technical
Support staff at our Farnborough, UK office:
Technical Support Dept.
Solartron
Victoria Road, Farnborough,
Hampshire GU14 7PW England
Telephone: +44 (0) 1252 376666
Fax: +44 (0) 1252 544981
Email: support@solartron.com
When you contact us, please supply the following information:
a. the make and model of your PC, its operating system and version,
b. the issue of the 1296 software you are using,
c. the nature of the problem. (Can it be easily reproduced?)
JWS / 1296 Operating Manual / Issue BB
Introduction: 1296 Dielectric Interface
1-5
1-6
Introduction: 1296 Dielectric Interface
JWS / 1296 Operating Manual / Issue BB
2
Installing the 1296
Contents
1
Hardware Installation ........................................................................................................... 2-3
1.1
High Voltage Measurements ........................................................................................ 2-5
2
Software Installation ............................................................................................................ 2-9
3
Initial Checkout .................................................................................................................... 2-9
List of Figures
Figure 2.1
Setting up the GPIB address switches in the 1296. ..................................................... 2-4
Figure 2.2
Connecting the 1296 system for normal operation. ..................................................... 2-4
Figure 2.3
Test circuit for a high voltage ac source. ..................................................................... 2-6
Figure 2.4
High voltage dc bias, using a floating power supply. ................................................... 2-7
Figure 2.5
High voltage dc bias, with grounded bias and capacitively coupled ac. ...................... 2-8
Figure 2.6
Impedance plot of the 12961 test circuit. ................................................................... 2-10
Figure 2.7
Various characteristics of the 12961 test circuit. ....................................................... 2-11
JWS / 1296 Operating Manual / Issue BC
Installing the 1296
2-1
2-2
Installing the 1296
JWS / 1296 Operating Manual / Issue BC
1
HARDWARE INSTALLATION
The procedure for installing the 1296 hardware is:
1. Check the GPIB address of each instrument to be included in the 1296
system and ensure that each address is unique and valid. The default GPIB
addresses assumed by the 1296 software are:
Dielectric Interface:
FRA:
DC Bias Controller:
Temperature Controller:
2
12 (and 13)
10
6
The 1296 is supplied with the GPIB address set to 2, and it is recommended
that you leave this as it is. However, if a change in the GPIB address of the
1296 is unavoidable then you can remove the top cover and set up the
required address as shown in Figure 2.1.
CAUTION: Should you remove the top cover of the 1296 to change the GPIB
address, you must:
a.
replace the cover promptly, to ensure that the dessicant bag remains dry,
b. before refitting the cover, ensure that the grounding lead is reconnected,
c.
when refitting the cover, ensure that the grounding clips are in place, and
will make good contact with the cover when this is in place.
Items b. and c. are necessary to maintain the emc performance of the 1296.
2. For normal operation, connect the 1296 hardware as shown in Figure 2.2.
Note that the FRA input connections vary according to the type of FRA used,
as shown in the following table. This shows the correspondence between the
connectors on the 1296 (first column) and the connectors on the various types
of FRA. (Details for connecting to the HP4192 are given in Appendix E)
1296
(Rear Panel)
1250
(Rear Panel)
1253
(Rear Panel)
1255
(Front Panel)
1260
(Front Panel)
Gen.
Gen, Hi*
Gen.
Gen.
Gen.
V1
Chan. 1, Hi*
Chan. 1
V1, Hi
V1, Hi
V2
Chan. 2, Hi*
Chan. 2
V2, Hi
V2, Hi
*Short circuit the Lo connection to ground, through a shorted BNC connector.
3. For operation with high voltage dc bias or high voltage ac, use the
connections detailed in Sections 1.1.1 and 1.1.2.
4. When taking measurements, ensure that the sample and reference cables are
not moved, to minimize measurement disturbance due to cable noise.
JWS / 1296 Operating Manual / Issue BC
Installing the 1296
2-3
To access the GPIB switches inside the 1296, slide back the cover on each corner, remove
the four top cover retaining screws and corner pieces, and disconnect the ground lead.
Then lift the cover clear.
With the GPIB switch
orientated as shown,
a logic ’1’ is obtained
when the relevant
toggle is set to the
left. In this example
the ’2’ toggle is set
for logic ’1’ and the
other toggles are set
for logic ’0’. Ignore
the logic notation on
the pcb.
1
2
4
8
16
Set the GPIB slider switches to the
required address. The set-up
shown here is for an address of 2.
-
Note: The ground lead must be reconnected before the cover is refitted. This is to ensure EMC
compliance.
Figure 2.1 Setting up the GPIB address switches in the 1296.
GPIB
PC
AC Supply
1296
(rear)
Gen V1 V2
1296
(Front)
GPIB
Lo Hi
Lo Hi
AC Supply
FRA
GPIB
Gen V1 V2
For details of connections on the various
types of FRA, see table on opposite page.
Sample
AC Supply
Reference*
*The use of a Reference Unit is optional.
Figure 2.2 Connecting the 1296 system for normal operation.
It is recommended that you use the GPIB cable (2 metre) HP10833B. This is
available from Solartron under part number 31203B.
2-4
Installing the 1296
JWS / 1296 Operating Manual / Issue BD
1.1
HIGH VOLTAGE MEASUREMENTS
Methods are available for testing samples at higher voltages than those offered
by the FRA generator output alone. There are two types of application:
a. testing with a high ac voltage,
b. testing with a low ac voltage, but with a high dc bias.
Both types of testing benefit from the use of the external reference mode, but
neither can be used with the internal reference mode.
CAUTION: The 1296 may be damaged if the test sample breaks down during
high voltage testing. Therefore, use a protection resistor to limit the fault current
to ±20mA. Correctly sited, this resistor should not affect the measurement.
WARNING: Where high voltage amplifiers or supplies are used, the appropriate
safety precautions must be taken. Consult the manufacturers operating
instructions.
1.1.1
Using a High Voltage AC Source
High ac voltage testing can be done using the circuit shown in Figure 2.3.
When an experiment is run the ac voltage applied to the sample is the
programmed value times the amplifier gain. However, the amplifier gain is not
taken into account by the software. This has the following effect:
•
impedance result = actual impedance ÷ amplifier gain.
•
capacitance result = actual capacitance × amplifier gain.
For example, a 100pF capacitor, measured using an amplifier gain of ×100,
appears to be a 100nF capacitor.
The voltage and frequency ranges covered depend on the performance of the
amplifier and attenuator. Results obtained in the Normal measurement mode
will have additional errors at high frequencies due to the attenuator
characteristics. These errors can be minimised by using the Reference mode,
with an external reference capacitor.
NOTE: The reference capacitance should be entered as it appears to the software.
In the example above a 100pF reference capacitance would be entered as 100nF.
JWS / 1296 Operating Manual / Issue BC
Installing the 1296
2-5
GPIB
PC
AC Supply
FRA
(1260)
Gen V1 V2
GPIB
AC Supply
1296
(rear)
SAMPLE REFERENCE
Lo Hi
Lo Hi
GPIB
Gen V1 V2
1296
(Front)
AC Supply
Protection
CSample
Amp
R4 100kΩ
R1
990kΩ
R2
1kΩ
CReference
R3
110kΩ
Figure 2.3 Test circuit for a high voltage ac source.
2-6
Installing the 1296
JWS / 1296 Operating Manual / Issue BC
1.1.2
Using a High Voltage DC Bias
Additional dc bias (up to 1kV, approximately) can be applied to the sample from
an external power supply. There are two methods of doing this:
a. Use a floating power supply, connected as shown in Figure 2.4.
b. Use a grounded bias circuit, with the ac source capacitively coupled as
shown in Figure 2.5.
Method a. is the preferred method, but it is limited by the effects of
floating-common to ground capacitance. Typically, this capacitance is in the
region of 500nF, which reduces the ac test voltage to about 70% of its low
frequency value at 6kHz.
Method b. is useful for higher frequencies, but the results at the lower
frequencies should be treated with caution. This is due to the following:
1. The test voltage falls off at low frequencies, due to the loading effect of R2
with C2. Measurement results are not affected until the test voltage becomes
very small. The low frequency performance can be improved by increasing
R2, but if any dc bias current is present the bias voltage is reduced.
2. The time constant of C3 and the 1MΩ input inpedance of the FRA combined
must be sufficiently large to minimise measurement errors at low
frequencies. The accuracy of tan delta, in particular, is badly affected by
phase shift. For this reason it is much better to use the external reference
method to cancel these errors out.
NOTES
1. The reference capacitor must be rated to withstand the test/bias voltage.
2. High bias voltages may give rise to dc bias currents larger than the ac
current. If this is the case then the 1296 is unable to range correctly and the
FRA indicates overload.
1296
(Front)
Lo Hi
Lo Hi
Output
HIGH VOLTAGE
POWER SUPPLY
Common
Ground
Sample
Reference
The other connections are the same
as those shown in Figure 2.2.
Figure 2.4 High voltage dc bias, using a floating power supply.
JWS / 1296 Operating Manual / Issue BC
Installing the 1296
2-7
GPIB
PC
AC Supply
FRA
(1260)
Gen V1 V2
GPIB
AC Supply
SAMPLE REFERENCE
Lo Hi
Lo Hi
GPIB
1296
(rear)
Gen V1 V2
1296
(Front)
AC Supply
R1
R2
C2
Output
HIGH VOLTAGE
POWER SUPPLY
C3
Common
Ground
C1
CSample
R1
10MΩ
C1
1nF, 4kΩ
R2
10MΩ, 100MΩ, or 1GΩ, whichever gives the best results
C2
10nF, 1.5kV polypropylene
C3
100nF, 1.5kV polypropylene
CReference
Optional filter
Figure 2.5 High voltage dc bias, with grounded bias and capacitively coupled ac.
2-8
Installing the 1296
JWS / 1296 Operating Manual / Issue BC
2
SOFTWARE INSTALLATION
The 1296 software is supplied on a set of floppy disks. To use 1296 with the
Hewlett-Packard HP4192, use 129604S software, details of which are given in
Appendix E.
To install the 1296 software:
1. Check that 1296 hardware is safely installed, and that the ac supply is
switched on.
2. Insert the first disk (#1) into Drive A on your PC.
3. Run: a:\setup.exe
4. Follow the on-screen instructions.
NOTE: CPU intensive screen savers can slow down or stop measurements. To
avoid this problem, the screen savers should be disabled or given a low priority.
3
INITIAL CHECKOUT
To satisfy yourself that the 1296 is working, use the following checkout
procedure:
1. Take a 12961 Dielectric Reference Module and connect the Test terminals to
the Sample terminals on the 1296.
2. In the menu bar of the 1296 operating window click the LMB2 on
‘Experiment’.
3. In the Experiment menu click the LMB on ‘Configuration Assistant’. This
opens each of the set-up windows in turn, beginning with the Instrument
Set-up window.
4. In the Instrument Set-up window check that the settings shown correspond
exactly with your hardware. Make any corrections necessary and then click
the LMB on ‘OK’. This opens the Experiment Set-up window.
5. In the Experiment Set-up window:
a. Specify a data filename, for example: Test.dat
b. Click the LMB on the Frequency button to open the Frequency Set-up
window.
c. Specify a frequency sweep between 1Hz and 1MHz, log scale, 5 points
per decade.
2 LMB= Left Mouse Button.
JWS / 1296 Operating Manual / Issue BC
Installing the 1296
2-9
d. Click the LMB on ‘OK’ in the Frequency Set-up window.
e. Click the LMB on ‘OK’ in the Experiment Set-up window. This opens the
Measurement Set-up window.
6. In the Measurement Set-up window ensure that Normal measurement is
selected, with a fixed integration time of 1 second. Then click the LMB on
‘OK’. This opens the Sample Definition window.
7. Cancel the Sample Definition window. (A sample definition is not required
for the initial checkout, because permittivity will not be displayed.)
8. Start the experiment, by clicking the LMB on the traffic light icon, and allow
the experiment to complete. The Graph Set-up window then opens
automatically.
9. In the Graph Set-up window:
a.
Enter the graph title, for example "Test Circuit Checkout #1".
b. Click the LMB on ‘OK’. After a short initialising delay the graph shown
in Figure 2.6 should appear.
Figure 2.6 Impedance plot of the 12961 test circuit.
10. In the graph window, click the LMB on the Set-up button. This re-opens the
Graph Set-up window. In the Graph Set-up window:
a. Select Impedance and Phase (Deg.) for the Upper Y-Axis and Y-Axis type.
b. Click the LMB on ‘OK’.
After a short initialising delay the phase plot shown in Figure 2.7a should
appear.
2-10
Installing the 1296
JWS / 1296 Operating Manual / Issue BC
11. Repeat step 10, as required, to select and plot various other characteristics of
the test circuit. Figures 2.7b and 2.7c show plots of capacitance and
capacitance tan delta against frequency.
a.
b.
c.
Figure 2.7 Various characteristics of the 12961 test circuit.
JWS / 1296 Operating Manual / Issue BC
Installing the 1296
2-11
2-12
Installing the 1296
JWS / 1296 Operating Manual / Issue BC
3
Setting Up and Running an Experiment
Contents
1
Using the 1296 ...................................................................................................................... 3-3
1.1
Accessing the 1296 Set-Up Windows .......................................................................... 3-4
2
Defining an Instrument Set-Up ............................................................................................ 3-5
3
Defining an Experiment ....................................................................................................... 3-7
3.1
Entering the Experiment Parameters ........................................................................... 3-8
3.2
Editing a List of Parameter Values ............................................................................. 3-11
3.3
Normalising a Measurement ...................................................................................... 3-13
4
Defining a Sample .............................................................................................................. 3-15
5
Setting Up a Measurement ................................................................................................ 3-16
6
5.1
Selecting the Measurement Method .......................................................................... 3-16
5.2
Selecting the Analyser Integration ............................................................................. 3-18
Using Stored Set-Ups ........................................................................................................ 3-19
List of Figures
Figure 3.1
The 1296 operating window. ....................................................................................... 3-3
Figure 3.2
The Instrument Set-up window. ................................................................................... 3-6
Figure 3.3
The Experiment Set-up window. .................................................................................. 3-7
Figure 3.4
The experiment parameter set-up windows ............................................................... 3-10
Figure 3.5
The "List of Measurement Points" window. ............................................................... 3-11
Figure 3.6
The Normalisation Data entry window. ...................................................................... 3-14
Figure 3.7
The Sample Definition window. ................................................................................. 3-15
JWS / 1296 Operating Manual / Issue BB
Setting Up and Running an Experiment
3-1
Figure 3.8
3-2
The Measurement Set-up window. ............................................................................ 3-16
Setting Up and Running an Experiment
JWS / 1296 Operating Manual / Issue BB
1
USING THE 1296
Broadly, there are three steps in using the 1296: setting up the system, making
the dielectric measurements, and displaying the results.
You set up the 1296 through various set-up windows (Instrument Set-up,
Experiment Set-up, etc.). Each window is opened by clicking on an icon in the
toolbar or making a selection from a drop-down menu. This is done in the main
operating window, which is shown in Figure 3.1.
A configuration assistant is also available, as an aid to the new user. This selects
each of the relevant set-up windows, in turn, to allow the initial parameters of
an experiment to be entered.
Dropdown menus
Toolbar
LOAD SAVE
Set-Up Set-up
INSTR.
Set-up
EXPT. MEAS. SAMPLE GRAPH
Set-up Set-up Defn
Set-up
Status Bar
START STOP
EXPT EXPT
HELP
TEXT
Clock
Figure 3.1 The 1296 operating window.
Once the 1296 and its companion instruments have been set up, you start the
experiment by clicking on the traffic light icon in the tool bar (or ‘Start’ in the
Experiment menu). You can then allow the experiment to complete or, if
necessary, stop it part-way. To stop an experiment, click on the Stop icon (or on
‘Stop’ in the Experiment menu).
Data obtained from an experiment may be displayed as a graph, or it can be
exported. (See Chapters 4 and 5.)
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Setting Up and Running an Experiment
3-3
1.1
ACCESSING THE 1296 SET-UP WINDOWS
To help the new user, the 1296 set-up windows can conveniently be opened by
selecting the configuration assistant in the Experiment menu. This gives access
to each set-up window in turn. When you complete a set-up, by clicking on OK,
the next window opens.
The set-up windows accessed by the configuration assistant are:
•
•
•
•
Instrument Set-up,
Experiment Set-up,
Measurement Set-up,
Sample Definition.
Each set-up window can also be accessed on its own. You do this by clicking the
LMB1 either on the relevant icon in the toolbar or on the relevant item in the
Experiment menu. (To display the toolbar, click on Show Toolbar in the
Options menu.)
Note: Clicking Cancel on a Configuration Assistant window aborts the window
sequence.
1 LMB=Left mouse button.
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JWS / 1296 Operating Manual / Issue BB
2
DEFINING AN INSTRUMENT SET-UP
For your PC to control the 1296 system, it must know the Instrument set-up.
Starting at the top of the Instrument Set-up window (Figure 3.2) enter the details
listed below. The default GPIB addresses of the dielectric interface and the FRA
agree with those set on the hardware, as supplied. You can if you wish select
different addresses from these, but all GPIB addresses entered must agree with
those set on the instrument hardware.
Impedance interface
Type
1296 or CDI (Chelsea Dielectric Interface).
(Note that 1294 is not an appropriate selection.)
Address
GPIB address of the dielectric interface.
Frequency Response Analyser (FRA)
Type
Solartron 1260, 1255, 1253, or 1250, or Hewlett Packard HP4192
(See Appendix E for details.)
Address
GPIB address of the FRA.
Note: The FRA uses two addresses the (even) one shown in the
Address box and the one which follows it. A warning is displayed if you attempt to enter the second FRA address for any of
the other instruments in your 1296 system.
DC Bias Controller
Type
FRA (as selected above), Other (an instrument other than the
FRA), or Manual (an instrument controlled from outside the system). Note: For each of these you enter the bias through the Experiment Set-up window.
For a bias control instrument other than the FRA...
Address
You must enter a GPIB address...
Set-up File
...and you must specify a DLL file and a set-up file. These contain
the instrument driver and set-ups.
If you choose to adjust the bias manually the program prompts
you to do this whilst the experiment is running.
Continued on next page....
JWS / 1296 Operating Manual / Issue BB
Setting Up and Running an Experiment
3-5
Temperature Controller
Type
Manual (an instrument controlled from outside the system, as selected above), Lakeshore 340, Oxford Instruments ITC503, or
Other (an instrument other than Lakeshore 340, etc.).
If you choose to adjust the temperature manually the 1296 program prompts you to do this whilst the experiment is running. If
no temperature control is required then select manual mode (and
select fixed with no prompt in experiment set-up).
NOTE: The temperature controllers Lakeshore 340 and Oxford Instruments ITC503 are set up, prior to being operated, from their
respective set-up files. These files, which are supplied with the
impedance measurement software, are Lakeshore.set and
oi_setup.set. Guidance on modifying the content of these files for
your particular application is given in Appendix C of this manual.
Address
For Lakeshore 340, Oxford Instruments ITC503, or any other
temperature control device, you must enter a GPIB address.
Set-up File
For Lakeshore 340 and Oxford Instruments ITC503, you must select a set-up file. For any other type of temperature control device, you must select a set-up file and a DLL file.
Figure 3.2 The Instrument Set-up window.
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3
DEFINING AN EXPERIMENT
To define an experiment you must specify the way in which the 1296 is to drive
the sample during the experiment. You must also specify the Data File in which
the 1296 is to store the results. Starting at the top of the Experiment Set-up
window (Figure 3.3) make the following entries.
Figure 3.3 The Experiment Set-up window.
Data File
Click on the [...] button and enter the name of the Data File that is to hold the
experiment results.
Experiment Description
Enter an experiment description of your choice (30 characters maximum). This
is to help you identify the set-up.
Repeat/Interval
Enter the number of times that the 1296 is to repeat the experiment. Also enter
the time that the 1296 must wait before repeating the experiment.
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Setting Up and Running an Experiment
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Constants
Enter constant drive values in the Fixed mode, from the relevant set-up window.
Each value has a delay, which also is entered from the set-up window. This
delay gives the drive time to settle before measurement starts. To open a set-up
window, double-click the LMB on the relevant row in the Constants table or
click on the relevant button: Interval, AC Level, DC Bias, Frequency, Temperature
Measurement Sequence
This is a list of the parameters that you wish to change during the experiment.
You enter the values for each of these parameters in the Sweep or List mode,
from the relevant set-up window. For each parameter you can also enter a
measurement delay: this gives each new value time to settle.
Each row in the Measurement Sequence table represents a level in a
measurement ‘tree’. As an example, assume that the table has two rows: the first
row specifies ac Levels of 1Vrms and 3Vrms; and the second specifies
frequencies of 1kHz, 2kHz, and 3kHz. In the measurement sequence, the
parameters thus specified are applied as follows: 1Vrms at 1kHz, 1Vrms at
2kHz, 1Vrms at 3kHz; 3Vrms at 1kHz, 3Vrms at 2kHz, 3Vrms at 3kHz.
Note that the parameter at the top of the Measurement Sequence table is the one
that changes least often. Similarly, the parameter in the second row changes less
often than the one in the third row, and so on down the table. Remember this
when creating a measurement sequence. Parameters, such as temperature, that
are slow to settle should normally be entered at the top. This ensures the
minimum use of long settling delays.
The position of a value in the measurement sequence table can be altered by
clicking the LMB on the relevant row and then clicking on the arrow buttons to
move the row up or down.
Measurement Repetitions
Enter the number of times that each measurement is to be made, within the
experiment.
3.1
ENTERING THE EXPERIMENT PARAMETERS
Values are assigned to each experiment parameter in a specific set-up window.
You can open the window in one of two ways: double-click the LMB on the
relevant entry in the Experiment Set-up window; or click once on the relevant
set-up button. The set-up windows that you can open in this way are shown in
Figure 3.4. The entries that you can make in these windows are described on the
next page.
Repeat/Interval
Enter the number of times that the experiment is to be repeated, and the interval
between the end of one experiment and the start of the next.
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Ac Level, Dc Bias, Frequency, Temperature
Each of these parameters can work in any one of the following modes:
Fixed
In this mode you enter a constant drive value for the parameter. This
value is applied throughout the experiment.
Sweep
In this mode you enter a start value and a stop value. These two
values define the limits of the sweep. You also enter the number of
points at which measurements are to be made. For AC Level and DC
Bias the measurement points follow a linear scale, from the start value
to the stop value. In a Frequency or Temperature sweep the
measurement points can be given a linear or log scale.
List
In this mode you enter a list of drive values and a measurement is
made for each one. You can derive the values from those contained in
a sweep, or you can enter any values that fit the experiment. See also
Section 6: ‘Editing a List of Parameter Values’.
In the DC Bias and Temperature set-up windows you may see the the entry
"Prompt for manual control". This appears in the respective window when
manual control for the related parameter is selected in the Instrument Set-up
window. To enable a prompt, click the LMB in the box to display a tick. A
prompt is then displayed when you may change the parameter value. In the
Temperature Set-up window you can also select the temperature units.
In the Frequency Set-up window you can select the units for the measurement
delay. The cycles setting is useful for measurements at very low frequencies.
In the Temperature Set-up window, the "At End of Experiment" options are
offered when temperature control other than manual is selected in the
Instrument Set-up window. The options allow you to take one of the following
actions at the end of the experiment:
•
Return the temperature to 20ºC.
•
Maintain the last temperature selected.
•
Turn off the heater.
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Setting Up and Running an Experiment
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Figure 3.4 The experiment parameter set-up windows
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3.2
EDITING A LIST OF PARAMETER VALUES
As an alternative to using a sweep you can enter a list of parameter values.
Create the list in one of two ways: either edit the values of a sweep or enter any
sequence of values that fits the experiment. You can save the list on file and
reload it later.
3.2.1
Opening The "List of Measurement Points" Window
1. In the Experiment Set-up window, click the LMB on a set-up button (for
example, AC Level) to open the set-up window.
2. In the set-up window, select the Sweep mode (with a valid sweep values) or
the List mode.
3. Click on the Edit List button to display the "List of Measurement Points"
window (Figure 3.5).
Figure 3.5 The "List of Measurement Points" window.
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Setting Up and Running an Experiment
3-11
3.2.2
Editing The Measurement Points List
In the "List of Measurement Points" window you can edit the measurement
points list as follows:
Insert a value:
1. Click the LMB on the value in the list above which the new value is to go.
2. Put the new value into the Value box.
3. Click on the Insert button.
Reposition a value:
1. Click the LMB on the value in the list.
2. Move the value up and down the list, with the arrow buttons.
Delete a Value:
1. Click the LMB on the value in the list.
2. Click on the Delete button.
Delete All values in the list, by clicking the LMB on the Delete All button.
Save a list, by clicking the LMB on the Save button and entering an appropriate
filename.
Load a previously-saved list, by clicking the LMB on the Load button and
specifying the filename.
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3.3
NORMALISING A MEASUREMENT
Normalisation is used primarily to cancel out errors in difficult measurement
environments. A typical application in which normalisation can be usefully
applied is where dielectric tests are done on samples that are heated or cooled
by a temperature controlled cryostat system. The long wires with which the
sample is connected are subject to many sources of stray impedance. It is
impractical to use the reference measurement mode, since this would require a
second cryostat of exactly the same construction as the one containing the
sample. Here, measurement normalisation can be used to full advantage.
Measurement normalisation corrects for the effect of stray impedances due to
such things as the connection cables, sample holder, temperature control system.
The measurements are made as quickly as possible, since only the sample is
measured −not the reference capacitor, as is the case in the reference
measurement mode.
Normalisation is applied at all the measurement frequencies of interest. A
frequency sweep is made with the cryostat, sample holder and connecting leads
set up as for the experiment, but without the sample inserted. This means that
the sample holder is measured as a capacitor with an air dielectric. Each
measurement result thus obtained comprises the impedance of the empty
sample holder, plus any stray impedances in the measurement system.
Provided that you know the geometry of the sample holder you can calculate
what its capacitance should be when empty. This value is entered as the
"Normalisation data needed...". The 1296 uses this value to calculate what the
impedance of the empty sample holder should be at each measurement
frequency. It then divides each calculated impedance value by the value
actually measured. This gives a normalisation factor for each measurement
frequency, which is stored in a normalisation file for future use.
Note that normalisation is most effective when the measured impedances are
similar to the calculated values used in normalisation. This can sometimes be
arranged by varying the separation of the sample holder plates.
The normalisation file for a particular experiment is created with a single sweep.
The sample may then be put into the sample holder, normalisation requested
from the specified normalisation file, and measurements made at different
temperatures.
In addition to the example of a cryostat there are many other cases in which
measurement normalisation can be usefully applied. These include the
measurement of fast changing systems, such as in the cure of adhesives,
thermoset polymers, etc., where it is important to capture data quickly and
accurately.
A normalisation file may be created in either of two ways. You can request a
normalisation run in the Experiment Set-up window, as described in Section
3.3.1 below, or you can convert a standard impedance data file into a
normalisation file, as described in Chapter 4, Section 1.4.
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3.3.1
Creating a Normalisation File with a Frequency Sweep
To create a normalisation file with a frequency sweep:
1. Connect the empty sample holder to the Sample inputs.
2. In the Experiment Set-up window:
a. set up the required experiment parameters and
b. enable Normalisation run by clicking the LMB in the box to display a
tick or cross. The Normalisation data needed... window is now displayed.
(See Figure 3.6.)
3. In the Normalisation data needed... window, enter the capacitance and
conductance of the sample presently connected and click the LMB on OK.
4. Complete the remainder of the system set-ups and start the measurement
sequence by clicking the LMB on the traffic light button.
An impedance measurement is now made of the sample at each frequency
point specified in the experiment set-up. For each measurement the
program divides the theoretical impedance value (computed from the
capacitance and conductance values entered in step 3) by the measured
impedance value. A normalisation factor for each frequency is thus
obtained. Note that the frequencies specified must include all the
frequencies likely to be used in future measurements normalised with the
presently created normalisation file.
The method of employing the normalisation file thus obtained is explained in
Chapter 4, Section 1.4.
Figure 3.6 The Normalisation Data entry window.
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4
DEFINING A SAMPLE
The Sample Definition window (Figure 3.7) enables you to enter the empty cell
capacitance of the sample, or the dimensions from which this may be derived.
The empty cell capacitance enables the 1296 to compute the relative permittivity
of the sample.
Figure 3.7 The Sample Definition window.
You can define a sample in either of two ways: enter the sample dimensions and
let the 1296 compute the empty cell capacitance; or enter the capacitance value
direct. The first method is suitable for a sample for which you know the
dimensions, but cannot remove the dielectric. The second method is suitable for
samples of an irregular shape: if you do not know the empty cell capacitance,
but you can remove the dielectric, the 1296 can measure the capacitance for you.
The entries that you can make are:
Dimensions
Circular cross-section and diameter (mm), or
Non-circular cross-section and area (mm2).
Sample thickness (mm).
Electrical Properties
Empty cell capacitance (pf).
Sample Comment
Here you can enter a description of the sample being
investigated.
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Setting Up and Running an Experiment
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5
SETTING UP A MEASUREMENT
The 1296 offers two methods of making a sample measurement - Normal or
Reference. With the Normal method, a single direct measurement is made. The
results that this gives are accurate at low frequencies, but errors due to stray
impedances can arise at high frequencies. To avoid this problem, you can use the
Reference method. With this, two measurements are made: one of the sample
and one of a reference capacitor of comparable value. From the ratio of the two
results and the reference capacitance value the 1296 computes the true sample
value.
To reject any noise that may be present in the sample signal the 1296 allows you
to select integration of the Analyser input.
5.1
SELECTING THE MEASUREMENT METHOD
You select the measurement method in the Measurement Set-up window
(Figure 3.8).
Figure 3.8 The Measurement Set-up window.
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JWS / 1296 Operating Manual / Issue BB
The measurement set-up defaults to normal measurement. To select the
reference method, click the LMB on the Reference option:
[Note: With CDI selected as the dielectric interface (see Section 2 in this chapter)
you can choose between Reference methods 1 and 2. These are the methods
used by the CDI to measure the sample and reference capacitors.]
With the Reference method you have the option of using the Normal method for
measurements below a specified frequency and the Reference method for
measurements at frequencies above. This is worth doing when you can obtain
the same accuracy with either method over the lower part of the frequency
range. The Normal method makes only one measurement per result and this
saves time. To combine the Normal and Reference methods in this way, click
the LMB in the Use Normal Mode Below box. Then specify a frequency, in Hz,
below which the Normal method is to be used:
The frequency that you enter depends on the sample and must therefore be
found by experiment. The easiest way to do this is to make two frequency
sweeps, one using the Normal method and the other using the Reference
method. Compare the results on a graph and note the frequency at which the
traces diverge. This is the frequency to put in the Use Normal Mode Below box.
You should then obtain a consistent accuracy throughout the sweep, for this
particular sample.
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Setting Up and Running an Experiment
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5.1.1
Selecting the Reference Capacitor
When you select the reference method you must also tell the 1296 which
reference capacitor to use. Click the LMB on the Internal button or the External
button. (For a CDI, the internal reference is not available when the Reference 2
measurement method is selected, or if your CDI has no internal reference
capacitors.)
For the internal reference, the 1296 automatically selects a capacitance that is
comparable to that of the sample. If you wish to use an external reference,
however, you must connect a suitable capacitor to the 1296 yourself. You must
also enter the values of this capacitor, in the External Capacitor boxes.
If you use a wide range of frequencies, you may need to use several different
values for the external reference capacitor to maintain measurement accuracy.
To do this you will need to conduct a series of experiments, for each experiment
using a suitable reference capacitor.
5.2
SELECTING THE ANALYSER INTEGRATION
Noise that is present in the signal applied to the Analyser can be rejected by a
process known as signal integration. This process averages the signal over a
whole number of cycles, which narrows the measurement bandwidth and thus
increases the signal to noise ratio. The more a signal is averaged the longer it
takes to get a result, so there is a trade-off between the accuracy you require and
the measurement speed.
The measurement set-up defaults to a fixed Integration Period, with auto
integration off:
If you wish to use a fixed integration period, enter the period you require, in
seconds or cycles, in the Integration Period box. Select cycles or seconds by
clicking on the relevant option button.
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JWS / 1296 Operating Manual / Issue BB
If you know what accuracy you want in your results, but you don’t know how
much integration is required to obtain this then a possible solution is to use Auto
Integration:
Auto Integration averages the signal until the standard deviation reaches a
target value. Details of the standard deviations obtained are given in the
relevant FRA manual. To avoid excessive measurement times, you assign a
Maximum Period, in seconds or cycles.
When you enter a value in seconds the 1296 always selects the most appropriate
number of whole cycles. You must specify at least one cycle for the Analyser to
operate.
6
USING STORED SET-UPS
To save you time in setting up the 1296, the following facilities are available
from the File drop-down menu:
Load Set-up
Allows you to load a previously saved configuration file.
Save Set-up
Allows you to save the present set-ups for the Instrument,
Experiment, Sample and Measurement, in a specified
configuration file.
Initialise Set-up
Sets the 1296 to a factory defined configuration.
Load Default
Sets the 1296 to the default configuration. (This is the
configuration in which the 1296 starts up.)
Save as Default
Saves the presently selected configuration as the default
configuration.
In addition to the above, any one of the last four user-defined configurations can
be recalled from the File drop-down menu.
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Setting Up and Running an Experiment
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4
Displaying and Printing Graphs
Contents
1
Setting Up and Displaying a Graph .................................................................................... 4-3
1.1
Selecting the Graph Type and Axis Functions ............................................................. 4-4
1.2
Scaling the Graph Axes ............................................................................................... 4-4
1.3
Selecting the Graph Data ............................................................................................. 4-6
1.4
Normalising the Graph Data ........................................................................................ 4-6
2
Using the Graph Facilities ................................................................................................... 4-8
3
Printing a Graph ................................................................................................................. 4-10
List of Figures
Figure 4.1
The Graph Set-up window. .......................................................................................... 4-3
Figure 4.2
The Axis Set-up window. ............................................................................................. 4-5
Figure 4.3
The normalisation data entry window. ......................................................................... 4-7
Figure 4.4
Using the Graph facilities. ............................................................................................ 4-9
Figure 4.5
Print Graph window for double Bode plot. ................................................................. 4-10
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Displaying and Printing Graphs
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JWS / 1296 Operating Manual / Issue BA
1
SETTING UP AND DISPLAYING A GRAPH
The procedure for setting up a graph is:
1. If no data is loaded, click the LMB1 on Load Data in the File menu.
2. Choose a datafile and open it.
3. Click the LMB on the graph toolbar button. (Or click on View Graph in the
Experiment menu.) The Graph Set-up window (Figure 4.1) is then
displayed.
4. Select the Graph Type: Complex Plane or Bode Plot. (See Section 1.1.)
5. Enter a Graph title and select a colour scheme. These are optional entries.
6. Select the Axes: horizontal function and type for upper (and lower) vertical
axes. (See Section 1.1.)
7. Open the Axis Set-up window and enter the Axis scaling and labels. (See
Section 1.2.) These are optional entries: automatic scaling is used by default.
8. Define the measurement results to be displayed. (See Sections 1.2 and 1.3.)
9. Click on OK to initialise and display the graph. To change a displayed graph
you can return to the Graph Set-up window. To do this, click the LMB on the
Set-up button in the Graph window.
Figure 4.1 The Graph Set-up window.
1 LMB= Left Mouse Button.
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Displaying and Printing Graphs
4-3
1.1
SELECTING THE GRAPH TYPE AND AXIS FUNCTIONS
For the graph type you can select a Complex Plane or a Bode Plot. Your choice
determines the axis functions that you must select.
For a complex plane you need select only the sweep parameter and the dielectric
function to be plotted. The real and imaginary parts of the selected function are
plotted for each value of the swept parameter.
For a Bode plot you can select a single or a double plot. For a single Bode plot
you select the parameters for:
a. the Upper X-Axis (example: frequency),
b. the Upper Y-Axis (example: impedance, admittance),
c. the Upper Y-Axis type (example: magnitude, phase).
To obtain a true plot of Tan Delta (as defined in Appendix B) select capacitance
or permittivity for the y-axis and Tan Delta as the y-axis type. Note that
permittivity requires that you define the empty cell capacitance of the sample, or
the cell geometry from which this can be obtained. (See Chapter 3, Section 4.)
For a double Bode plot you select a common X-Axis parameter. The parameters
for the two Y-Axes are entered individually, using the Upper and Lower Y-Axis
and Y-Axis type buttons to enable the relevant menus.
1.2
SCALING THE GRAPH AXES
You can define the scale and the graph axes, according to your taste, from the
Axis Set-up window. See Figure 4.2. To open this window, you click the LMB
on the Axis Set-up button in the Graph Set-up window.
By default the graph axes are set as follows:
•
The axes are labelled according to the functions assigned to them in the
Graph Set-up window.
•
The axis limits are automatically assigned to cover the range of the data to be
plotted. (Auto Scale is selected.)
•
For Bode plots the X- and Y- axes both have a logarithmic scale −except when
phase is selected, when the vertical axis has a linear scale. (Should you select
a Complex Plane in the Graph Set-up window the graph will default to a
linear scale on both axes. This is regardless of the scale type shown in the
Axis Set-up window. You are made aware of such a change by a displayed
warning.)
With Auto Scale selected you can make the following adjustments:
a. You can enter your axis titles in the Axis Label boxes. This allows you to
relate a graph more closely to an experiment.
b. For a Bode plot you can select a logarithmic or a linear scale on either axis
independently. This allows you to plot your data in the most appropriate
way.
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JWS / 1296 Operating Manual / Issue BA
With Auto Scale de-selected you can, in addition, define the axis limits by
entering the Min and Max values. This allows you to plot a selected part of the
original data. Also, by entering the number of major and minor ticks required
you choose appropriate graduations for the graph axes. Note that the Major and
Minor Tick values are ignored when log scale is selected.
When the Axis Set-up window is first displayed, Max, Min, Major Ticks, and
Minor Ticks are set to their default values (Figure 4.2a). Once an auto-scaled
graph has been plotted, Max and Min take on the auto-scaled values (Figure
4.2b).
With a complex plane graph selected, the isotropic and invert Y axis facilities
become available (Figure 4.2c). Isotropic selects the same scaling for the X and Y
axes: this enables circular and semi-circular plots to be clearly recognised as
such. Invert Y Axis rotates a plot about the X axis: negative Y values are thus
displayed in the first quadrant, but with a negative scale.
a
b
c
Figure 4.2 The Axis Set-up window.
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Displaying and Printing Graphs
4-5
1.3
SELECTING THE GRAPH DATA
On each graph you can display up to eight traces. The data for these can come
from one datafile or several. A double Bode plot can support eight traces on
each plot. The graph set-up defaults to Trace No 1 enabled. (See Figure 4.1.) The
data for this comes from the datafile named in the Data File box. A description
of the experiment from which the data originates should appear in the box
below. (This description is entered from the Experiment Set-up window, before
the experiment is run.) Where more than one datafile has been loaded you can
select a different one from the Data File list. Otherwise, you can load the datafile
you need from the datafile select window: call this up by clicking with the LMB
on the [...] button.
To display another trace, select the Trace Number and click with the LMB in the
Enabled box. A trace is enabled when the Enabled box contains a cross (or tick).
If you wish to remove a trace from the graph, click again in the Enabled box to
delete the cross (or tick).
Below the Experiment Description box are the experiment parameter boxes.
These contain the parametric values used for the data to be displayed. Where a
datafile contains the data for multiple sweeps, each parameter box can contain a
list of values: to see such a list, click with the LMB on the down arrow button.
The listed values allow you to assign each trace to a particular phase in an
experiment. To do this, enable each trace you want to plot with the relevant
values selected. To help you to relate to the original experiment, the order of the
parameter boxes (top to bottom) is the same as that used in the measurement
sequence. To reveal information on the experiment configuration, click the LMB
on the [?] button.
To help you pick out a particular trace in a multi-trace plot each trace has a
unique colour. You can select the colour and line type of each trace to suit your
taste. Similarly, you can select the trace markers.
1.4
NORMALISING THE GRAPH DATA
To normalise the graph data you select a normalisation file and click the LMB on
the normalisation enabling box.
A normalisation file can be created by requesting a normalisation run in the
Experiment Set-up window. (See Chapter 3, Section 3.3.) However, it is also
possible to convert a standard data file into a normalisation file.
The procedure is:
1. In the Graph Set-up window, select the data file and characteristics of the
graph that you want
2. Select an appropriate data file to Normalise to and enable normalisation by
clicking the LMB in the box to display a tick or cross.
4-6
Displaying and Printing Graphs
JWS / 1296 Operating Manual / Issue BA
3. If the file you select is not a normalisation file, the Normalisation data needed...
window is displayed. (Figure 4.3.) Enter appropriate capacitance and
conductance values and click the LMB on OK. If the Normalisation data
needed... window is not displayed it means that the selected file is already a
normalisation file: in this case go directly to step 4.
4. Click the LMB on OK in the Graph Set-up window. After a short
initialisation delay, a graph of the data contained in the file selected from the
‘Data File’ list is displayed, normalised according to the selected
normalisation file.
Figure 4.3 The normalisation data entry window.
JWS / 1296 Operating Manual / Issue BA
Displaying and Printing Graphs
4-7
2
USING THE GRAPH FACILITIES
With a graph is displayed, the following facilities become available:
•
Zoom
•
Cursor
•
Grid
•
Legend
Graph zoom enables you to magnify a selected part of a plot. The data plotted
has the same measurement resolution, but the data points are more widely
spaced. This allows you to see individual points more clearly. Zoom in by
selecting the area of interest with the LMB: unzoom by disabling zoom.
The cross-line cursor enables you to get a precise reading of each data point on
the displayed plot. As you move the cursor along the trace, a precise reading of
the intersect point appears in the lower right hand corner of the graph window.
The grid extends the scaling of the X and Y axes over the whole display area.
This allows the value of any point on the plot to be seen at a glance.
The legend panel contains the title of each plot, against colour-coded plot
identities.
To enable each facility, click the LMB in the relevant box. In each case the
facility is enabled when the Enabled box contains a cross (or tick). Click again to
delete the cross (or tick) if you wish to disable zoom or cursor.
You can use the graph facilities independently or together. If you wish to use
zoom and cursor together you should select cursor before zooming: selecting the
cursor with a zoomed plot displayed causes the plot to revert to the pre-zoom
state.
Figure 4.4 shows:
a. Bode plot of two traces, with the grid and legends,
b. complex plane plot of the same data, with the grid and legends,
c. a zoomed version of the complex plane plot, with the cursor and legends.
4-8
Displaying and Printing Graphs
JWS / 1296 Operating Manual / Issue BA
Figure 4.4 Using the Graph facilities.
JWS / 1296 Operating Manual / Issue BA
Displaying and Printing Graphs
4-9
3
PRINTING A GRAPH
To print a graph:
1. Display a graph.
2. In the Graph window, click the LMB on the Print button. This brings up the
Print Graph window. See Figure 4.5.
3. In the Print Graph window select the graph format. For a Double Bode plot
you have the option of printing: the Upper and Lower plots; the Upper plot
only; or the Lower plot only. For Double Bode, Single Bode, or Complex
Plane you also have the option of printing the graph on a full page, or not, of
maintaining the graph aspect ratio, or not, and of printing the graph
background, or not.
4. Set up the standard windows print options. To access these, you click the
LMB on the Printer Set-up button.
5. Click the LMB on the Print button.
Figure 4.5 Print Graph window for double Bode plot.
4-10
Displaying and Printing Graphs
JWS / 1296 Operating Manual / Issue BA
5
Exporting Graphs
and Measurement Data
Contents
1
Exporting a Graph ................................................................................................................ 5-3
2
Exporting the Measurement Data ....................................................................................... 5-4
List of Figures
Figure 5.1
Export Graph Data window. ......................................................................................... 5-2
Figure 5.2
Graph data exported to Excel as a CSV format text file. ............................................. 5-3
Figure 5.3
Data Export for Excel window. ..................................................................................... 5-4
Figure 5.4
Measurement dataset exported to Excel as a .CSV file. ............................................. 5-5
JWS / 1294/1296 Operating Manual / Issue AA
Exporting Graphs and Measurement Data
5-1
a.
b.
c.
Figure 5.1 Export Graph Data window.
5-2
Exporting Graphs and Measurement Data
JWS / 1294/1296 Operating Manual / Issue AA
1
EXPORTING A GRAPH
You can export a graph in three ways:
•
•
•
as an image, to the windows clipboard,
as an image, to a windows metafile (WMF),
as data, to a CSV1 format text file (Figure 5.2).
The procedure is:
1. Click the LMB2 on the Export button in the graph window. This reveals the
Export Graph Data window (Figure 5.1a).
2. For a WMF image or CSV text file, click the LMB on the relevant option
button (Figure 5.1b) and enter the filename.
3. If you wish to start a WMF image file or CSV text file in its associated
application, click on the "Start File in Associated Application" box to display
a cross or tick (Figure 5.1c).
4. Click the LMB on the Export button in the Export Graph Data window. A
displayed message tells you whether or not the graph data has been
exported successfully.
Figure 5.2 Graph data exported to Excel as a CSV format text file.
1 CSV= Comma Separated Variables.
2 LMB= Left Mouse Button.
JWS / 1294/1296 Operating Manual / Issue AA
Exporting Graphs and Measurement Data
5-3
2
EXPORTING THE MEASUREMENT DATA
You can export the complete measurement dataset to the following applications:
•
•
•
Excel, as a .CSV file,
LEVM, as an .lev file,
ZView, as a .Z60 file.
LEVM and ZView are graphing and curve fitting programs, which are available
from Solartron.
The procedure for exporting measurement data is:
1. Click the LMB on Export in the menu bar.
2. Click to select your application from the export menu:
a. For Excel (CSV)...
b. For LEVM...
c. For ZView...
3. In the window now displayed (Figure 5.3) enter the names of the data source
and destination files...
4. ... then click on the Export button.
A displayed message tells you whether or not the data has been exported
successfully.
Figure 5.3 Data Export for Excel window.
5-4
Exporting Graphs and Measurement Data
JWS / 1294/1296 Operating Manual / Issue AA
Figure 5.4 Measurement dataset exported to Excel as a .CSV file.
JWS / 1294/1296 Operating Manual / Issue AA
Exporting Graphs and Measurement Data
5-5
5-6
Exporting Graphs and Measurement Data
JWS / 1294/1296 Operating Manual / Issue AA
6
Using the Experiment Batch Facility
Contents
1
Introduction .......................................................................................................................... 6-3
2
Procedure ............................................................................................................................. 6-3
2.1
Batch Functions ........................................................................................................... 6-3
List of Figures
Figure 2.1
The Batch Execution Set-up window. .......................................................................... 6-2
JWS / 1294/1296 Operating Manual / Issue AA
Using the Experiment Batch Facility
6-1
Figure 6.1 The Batch Execution Set-up window.
JWS / 1294/1296 Operating Manual / Issue AA
Using the Experiment Batch Facility
6-2
1
INTRODUCTION
The batch facility of the 1296 enables you to run a series of experiments. The
batch definition contains the configuration and data files of each experiment to
be done, in the order of execution. Where external equipment needs to be set
up, executable files may also be included in the list.
2
PROCEDURE
The procedure for setting up and running a batch is:
1. In the Experiment menu, select Batch Execution. This opens the Batch
Execution Set-up window (Figure 6.1).
2. In the Batch Execution Set-up window, use the following functions to set up
and run a batch of experiments.
2.1
BATCH FUNCTIONS
2.1.1
Add Experiment
To add an experiment to a batch, click the LMB1 on the Add Exp button. This
opens the Add Experiment window. Use this to enter the experiment
description and the names of its Configuration and Data files:
1 LMB= Left Mouse Button
JWS / 1294/1296 Operating Manual / Issue AA
Using the Experiment Batch Facility
6-3
2.1.2
Add File
To add an executable file to a batch, click the LMB on the Add File button. This
opens a window in which you can choose an executable file.
2.1.3
Load
To load a previously saved batch, click the LMB on the Load button. A window
then opens for you to choose a batch. If a suitable batch is available, select it and
click on OK. Otherwise, cancel and use the Add Exp and Add File functions to
create a new batch -or select a similar batch and modify it.
To modify a batch you can re-order experiments, delete them and add them.
You can also specify other datafiles. To move an item in the batch list, select the
item and use the up or down arrow button. To delete an item, click on the
Remove button.
2.1.4
Edit
Edit replaces a selected file with a different file of the same type. For example, if
you click the LMB on an experiment in the batch list and then click on the Edit
button the Add Experiment window opens. Any file that you now select
replaces the one in the batch list.
2.1.5
Save
To save a batch definition, click on the Save button and enter a suitable filename.
2.1.6
Run
To run a batch, click on the Run button.
NOTE: Executable files must finish and remove themselves from memory
before the batch sequence continues.
6-4
Using the Experiment Batch Facility
JWS / 1294/1296 Operating Manual / Issue AA
A
1296 Specification
Contents
A.1
12966001_AB
1296 SPECIFICATION .......................................................................A-3
A-1
A-2
12966001_AB
A.1
1296 SPECIFICATION
Characteristics dependent on type of FRA used:
Type of FRA used with 1296
1296+FRA
Characteristic
1260 or 1255
1250
Frequency Range
10µHz to 10MHz
10µHz to 65kHz
Signal Amplitude
up to 7Vrms*
up to 10Vrms
up to 10Vrms
up to ±40V
up to ±10V
up to ±10V
DC Bias
1253
10mHz to 20kHz
* For signals >3Vrms an internal amplifier is used: signal amplitude + dc bias must not exceed 10Vpeak.
Current Measurement:
1fA to 100mA.
Tan Delta Range:
<10-4 to 103 (10-2 to 103 at >1MHz) in ref. mode.
Impedance Range:
100Ω to >100TΩ (1014Ω).
Capacitance Range:
1pF to >0.1F.
Software:
Provides control of FRA, 1296, optional temperature
controller, dc bias and provision for ac signal
amplifiers.
Result Parameters:
Admittance (Y*), Impedance (Z*), Complex
Capacitance (C*), Permittivity (e*), Tan Delta (e"/e')
plotted v. frequency, time, temperature, bias, ac
level.
on Bode, complex plane.
Power Supply:
85Vac - 264Vac (47Hz - 440Hz).
Fuse T1.25A.
Power Consumption:
30VA maximum.
Dimensions:
340mm (13.39in.) wide × 120mm (4.72in.) high ×
300mm (11.81in.) deep.
Weight:
5.5kg (12.13lb)
Operating Temperature:
10°C to 30°C (50°F to 86°F).
12966001_AB
A-3
1n
100p
10p
1p
100T
10f
10n
10T
100f
100n
<5% accuracy (typical)
1µ
<2% accuracy (typical)
1p
1T
10p
100G
<0.2% accuracy (typical)
10µ
100p
10G
100µ
1n
1G
1m
10n
100M
Ω)
Z (Ω
Y (S)
10m
100n
10M
100m
1µ
1M
1
10µ
100k
10
100µ
10k
1m
1k
100
10m
10
100m
1µ
10µ
100µ
1m
10m 100m
1
10
100
1k
10k
100k
1M
10M 100M
Frequency (Hz)
Accuracy of real capacitance values (typical), measured in the reference mode
The measurement accuracy of the 1296 may be degraded should the instrument be subjected to high
levels of radiated or conducted radio-frequency interference as defined in EN50082-1.
A-4
12966001_AB
B
Measurement Term Definitions
Contents
1
Measurement Term Definitions ........................................................................................... B-3
1.1
Admittance ................................................................................................................... B-3
1.2
Impedance ................................................................................................................... B-3
1.3
Complex Capacitance .................................................................................................. B-3
1.4
Permittivity ................................................................................................................... B-3
1.5
Modulus ....................................................................................................................... B-4
1.6
Tan Delta ..................................................................................................................... B-4
JWS / 1294/1296 Operating Manual / Issue AA
Measurement Term Definitions
B-1
B-2
Measurement Term Definitions
JWS / 1294/1296 Operating Manual / Issue AA
1
MEASUREMENT TERM DEFINITIONS
The following definitions relate to the various quantities calculated by the
impedance measurement software.
1.1
ADMITTANCE
Admittance (Y* = I*/V* = G+jB) is displayed in Bode or Nyquist plots as
conductance G (real) and susceptance B (imaginary). This is the basic quantity
calculated as each measurement is made. Admittance corresponds to a parallel
combination of resistive and reactive elements and is expressed in siemens (S).
Admittance is also displayed on Bode plots, using the polar parameters of
magnitude and phase.
1.2
IMPEDANCE
Impedance (Z* = V*/I* = R+jX) is displayed as resistance R (real) and reactance
X (imaginary). Impedance corresponds to a series combination of resistive and
reactive elements and is expressed in ohms (Ω). This is the form in which each
result is held in the 1296 data output file.
1.3
COMPLEX CAPACITANCE
The concept of complex capacitance is used in dielectric studies. If we consider
admittance of a complex capacitor to be equivalent to the simple combination of
R and C in parallel, we get:
jωC* = G+jωC
∴C* = G/jω+C
= C− jG/ω
Note that the imaginary part is negative. The complex capacitance is defined as
C* = C’− jC’’ so that, in this simple example, C’ = C and C’’ = G/ω, both positive.
1.4
PERMITTIVITY
The expression for permittivity can be derived as follows:
C = ε.A/d
where ε = permittivity,
A = electrode area (m2)
d = thickness of dielectric (m)
also ε = εo.εr
where εo = permittivity of free space = 8.85419e-12 F/m
εr = relative permittivity of dielectric material
From this ε = C.d/A or, in complex form, ε* = C*.d/A = (C’− jC’’)d/A = ε’− jε’’
It then follows that εr* = ε*/εo = εr’- jεr’’ ; εr’ = ε’/εo ; εr’’ = ε’’/εo
JWS / 1294/1296 Operating Manual / Issue AA
Measurement Term Definitions
B-3
1.5
MODULUS
Some researchers favour the use of dielectric modulus M* = 1/ε*
1.6
TAN DELTA
The phase angle between voltage and current in a capacitor is nominally 90°. A
(normally) small deviation δ from 90° is caused by the power loss in the
capacitor. The loss factor or tan delta of the capacitor or dielectric material is the
ratio of this power, VIsinδ, to the purely reactive component VIcosδ. It can be
calculated from:
tan delta = C’’/C’ or ε’’/ε’
This should be a positive value.
B-4
Measurement Term Definitions
JWS / 1294/1296 Operating Manual / Issue AA
C
Temperature Controller Set-Up Files
Contents
1
Introduction .......................................................................................................................... C-3
2
Lakeshore 340 Set-Up File .................................................................................................. C-4
3
Oxford Instruments ITC503 Set-Up File ............................................................................. C-6
3.1
File Format ................................................................................................................... C-6
3.2
Temperature Stabilisation ............................................................................................ C-6
3.3
Driver Parameters ........................................................................................................ C-7
3.4
Typical ITC503 Set-Up File .......................................................................................... C-7
List of Figures
Figure C.1
Cryostat temperature sensing with Lakeshore 340. .................................................... C-4
JWS / 1294/1296 Operating Manual / Issue AA
Temperature Controller Set-Up Files
C-1
C-2
Temperature Controller Set-Up Files
JWS / 1294/1296 Operating Manual / Issue AA
1
INTRODUCTION
The set-up files for the Lakeshore 340 and Oxford Instruments ITC503 temperature
controllers, supplied with the Impedance Measurement software, are intended as
examples. Although these files, as supplied, are fully workable, the object is
that users should edit the files to suit their particular needs. An explanation of
the commands and parameters for the Lakeshore340 and Oxford Instruments
ITC503 can be found in the operating manuals provided with those instruments.
Sections 2 and 3 of this appendix give typical examples of the temperature
controller set-up files and general advice on how to use them.
JWS / 1294/1296 Operating Manual / Issue AA
Temperature Controller Set-Up Files
C-3
2
LAKESHORE 340 SET-UP FILE
A Cryostat has two temperature sensors, "Heater" and "Sample", whilst the
Lakeshore 340 has two sensor inputs "A" and "B". (See Figure C.1.) The normal
method of using the cryostat is to connect input "A" to "Heater" and input "B" to
"Sample", and to control the cryostat heater from "A".
Cryostat
Lakeshore 340
HEATER
Sensor A
SAMPLE
Sensor B
Figure C.1 Cryostat temperature sensing with Lakeshore 340.
Since "B" lags behind "A", a settle period is configured to allow the temperature
to stabilise at a temperature nearer to "A". The alternative allowed by the
software is to control the cryostat with the sample temperature sensed at "B".
Controlling the cryostat from the "B" input is a more accurate way of controlling
the sample temperature, but it depends on there being a good thermal link
between "A" and "B" in the cryostat. A poor thermal link can result in control
loop instability and thermal runaway. You will need to decide which method is
the best for your particular experiment. (If you control the cryostat temperature
from the sensor "B" input, the sensor "A" input should be disabled.)
After transmitting the SETUP file to the controller, the DLL takes the following
actions.
1. Sends CSET? to determine the control input. It assumes for now that the
other input is on the sample.
2. Sends INSET? <Control Input> to verify that the control input is enabled.
3. Sends RDGST? <Control Input> to verify that the control Input is
configured.
4. Sends INSET? <Sample Input> to verify that the sample input is enabled. If
the sample input is not enabled, the control temperature is returned as the
sample temperature.
5. If the sample input is enabled, sends RDGST? <Sample Input> to verify that
the sample input is configured. If this is not so, the control temperature is
used as the sample temperature. The sample temperature and the setpoint
are both stored in the results file.
C-4
Temperature Controller Set-Up Files
JWS / 1294/1296 Operating Manual / Issue AA
Below is a typical example of a Lakeshore set-up file. In this particular example,
sense input "A" of the Lakeshore 340 is enabled and sense input "B" is disabled.
! Lines Begining with ! are ignored
! All Commands are Converted to Upper Case before being
! Sent to the Temperature Controller.
!
! MAXIMUM PERMITTED LINE LENGTH IS 255 Chars
!
! The Only Query Allowed is BUSY?, which will wait
! For the response from the Controller to be 0
!
!
! Turn Off The Heater
RANGE 0
!
! Turn Off Ramping
RAMP 1,0,0
!
! Set Platinum 100(500Ohm) on Input A
INTYPE A,4
BUSY?
!
! Select Curve 4 for Input A
INCRV A,4
!
! Set Input A to be Enabled, B to be Disabled
INSET A,1,0
INSET B,0,0
!
!Setup The Display
DISPLAY 1,60
DISPFLD 1,A,1
!
! Set Limits dependant of Cryostat
CLIMIT 1,500,0,0,4,5
!
! Configure Control Loop 1,InputA, Units Kelvin, ON, Enable at power up
CSET 1,A,1,1,1
!
! Set Stability Condition = Within 1.5 Degrees for 30 Seconds
SETTLE 1.5,30
!
! Wait for not Busy
BUSY?
!
! Allow heater to go to Maximum range
RANGE 5
! End of Setup File
JWS / 1294/1296 Operating Manual / Issue AA
Temperature Controller Set-Up Files
C-5
3
OXFORD INSTRUMENTS ITC503 SET-UP FILE
This section describes the setup file that is used to initialise the Oxford
Instruments ITC503 Temperature Controller.
3.1
FILE FORMAT
In the ITC503 set-up file there are lines of three types:
1. Lines begining with ! are comments and are ignored.
2. Lines begining with % define some driver parameters, as described below.
3. Other lines (including blank ones) are sent to the ITC503 as commands.
See the ITC503 manual for full details of the commands available.
Lines may contain up to 255 characters.
3.2
TEMPERATURE STABILISATION
The driver internally decides when the sample temperature has reached
stability, before any impedance measurements are made. The stability test is
very flexible and can be configured using the driver parameters listed in Section
3.3. The driver keeps an internal history of measured temperatures and uses
these to decide when the sample temperature is stable, as follows:
1. The driver waits until the control channel temperature is within a small span
of the requested temperature. The span is defined by %TStabTolerance. This
test is optional and is done only if %TStabControlTarget is non-zero.
2. Similarly, the driver waits until the sample channel temperature is within a
small span of the requested temperature. The span is defined by
%TStabTolerance. This test is optional and is done only if
%TStabSampleTarget is non-zero.
3. A moving standard deviation of the measured sample temperatures is
calculated and the driver waits until this value is less than %TStabSD kelvin
before deeming the temperature to be stable. The standard deviation is
calculated over a time window of the most recent %TStabPeriod
milliseconds of temperature readings.
C-6
Temperature Controller Set-Up Files
JWS / 1294/1296 Operating Manual / Issue AA
3.3
DRIVER PARAMETERS
The driver parameters for the ITC503 are:
%ControlChannel = n
This defines the channel (1-3) whose temperature
is to be controlled by the temperature controller.
%SampleChannel = 2
This defines the channel (1-3) whose temperature
is to be interpreted as the sample temperature. It
can be the same as the control channel.
%TStabPeriod = 10000
%TStabSD = 0.1
%TStabControlTarget = 1
%TStabSampleTarget = 0
%TStabTolerance = 0.1
3.4
These are temperature stabilisation parameters,
as described above.
TYPICAL ITC503 SET-UP FILE
%ControlChannel = 1
%SampleChannel = 1
%TStabPeriod = 10000
%TStabSD = 0.1
%TStabControlTarget = 1
%TStabSampleTarget = 0
! Control temperature channel is 1.
! Sample temperature channel is 1.
! 10s stabilisation period.
! Temperature SD to be less than 0.1 K.
! Wait for the control temperature to reach target.
! Allow the sample temperature to differ from the
! target.
! Temperatures must be within 0.1K of target.
%TStabTolerance = 0.1
!
! Go into manual mode:
A0
!
! Turn the heater off:
O0
!
! Turn the gas flow off:
G0
!
! Use the following command to set the maximum heater output (in volts) if
! required. Note that 0 has a special significance - see the ITC manual:
!
M20
!
! Set the PID controller terms if required:
!
P25
!
I0.5
!
D0
JWS / 1294/1296 Operating Manual / Issue AA
Temperature Controller Set-Up Files
C-7
C-8
Temperature Controller Set-Up Files
JWS / 1294/1296 Operating Manual / Issue AA
D
1296 Sample Holders
Contents
D.1
INTRODUCTION ................................................................................D-3
D.2
1296 2A SAMPLE HOLDER...............................................................D-3
D.2.1 Sample geometry ..................................................................D-4
D.2.2 Using the micrometer ............................................................D-4
D.2.3 Guard ring .............................................................................D-4
D.2.4 Changing the fixed (‘lo’) electrode .........................................D-5
D.3
1296 4A LIQUID SAMPLE HOLDER..................................................D-6
D.3.1 Using the 1296 4A.................................................................D-6
D.4
NORMALISATION..............................................................................D-7
D.4.1 Method 1 - matched geometry ..............................................D-7
D.4.2 Method 2 - matched capacitance ..........................................D-7
(Used separately, this document has part number 12966006A/Issue AB)
12966001_BC
D-1
D-2
12966001_BC
D.1
INTRODUCTION
The sample holders available for use with the 1296 Dielectric Interface
measurement system are listed below:
• 1296 2A sample holder is designed for room temperature testing of solid
samples, and has 20mm diameter electrodes. It consists of two parallel
electrodes, one fixed and the other which can be moved into contact with the
sample by adjusting the built-in micrometer.
• 1296 3A electrode kit contains a set of additional fixed electrodes for testing
solid samples of various sizes; electrode diameters are 10mm, 30mm and
40mm. It must be used with the 1296 2A sample holder.
• 1296 4A liquid sample electrode kit has electrodes for use with the 1296 2A
for testing liquid samples.
Sample thickness can range from 0.2 to 25.4mm, and the impedance
measurement range is 1Ω to >100TΩ. All 1296 sample holders utilise guard ring
techniques to reduce the effect of stray fields at the edge of the sample (see
section D.2.3). For increased accuracy, normalisation should be employed (see
section D.4).
For information about sample holders for high and low temperature applications
using cryostats and furnaces, please contact Solartron.
Warning
Do not attempt to disassemble the fixed electrodes for solid samples. Any
attempt to do so will adversely affect measurement accuracy, and will render
the warranty invalid.
D.2
1296 2A SAMPLE HOLDER
The 1296 2A sample holder is designed to allow accurate tests of high impedance
solid materials at room temperature. The sample holder consists of two parallel
electrodes, one of which is fixed in position (the ‘Lo’ electrode) and the other
which can be moved into contact with the sample by adjustment of a micrometer
(the ‘Hi’ electrode). The size of the active region of the Lo electrode for the
standard sample holder is 20mm diameter. The 1296 3A electrode kit is available
for testing materials of different sizes.
12966001_BC
D-3
D.2.1
SAMPLE GEOMETRY
The 1296 software requires knowledge of the geometry of the sample. The
thickness of the sample can be read from a micrometer digital display which is
included as part of the sample holder, and the area of the sample is defined by
the area of the central Lo electrode. These dimensions are used in the 1296 PC
software to calculate the permittivity of the material (which is independent of
the size of the sample), using the formula:
ε = C.d/A
where
ε = permittivity (F/m)
C = capacitance (F)
d = thickness (m)
A = area (m2)
This allows results from materials of different sizes to be compared.
Results can be displayed using the 1296 software as absolute or relative
permittivity. Relative permittivity of the material, also known as the “dielectric
constant” is calculated as:
εr = ε / ε0
where:
εr = relative permittivity
ε = permittivity of sample
εο = permittivity of free space (8.85419E-12 F/m)
D.2.2
USING THE MICROMETER
For accurate measurements of the sample thickness, the micrometer should first
be zeroed. This is done by removing the sample and moving the electrodes into
contact with each other using the micrometer adjustment thimble. The
micrometer is then zeroed by pressing the ‘Zero/Abs’ button. (Refer to
instructions supplied with the micrometer for details).
The micrometer display can be configured for display of thickness in mm or
inches as required.
D.2.3
GUARD RING
The 1296 2A makes use of a guard ring on the fixed electrode in order to reduce
the effect of stray field lines at the edge of the sample which would otherwise
lead to measurement errors (see figure D-1). The guard ring ensures that the
electric field lines are parallel throughout the part of the sample which
contributes to the impedance measurement.
D-4
12966001_BC
“Hi” Electrode
Sample
Insulation
Guard Ring
“Lo” Electrode
Figure D-1: Electrode arrangement of the 1296 2A sample holder
The guard ring is connected to ground on the sample holder, while the Lo
electrode is virtually the same ground potential because the current to voltage
converter in the 1296 is a ‘virtual earth’ device. There is no potential difference
between the Lo electrode and the guard ring and therefore the field lines at the
edge of the “Lo” electrode are maintained parallel to each other. The impedance
of the sample is calculated from the voltage drop across the sample and the
current which goes through the central part of the sample only (where the field
lines are parallel). The current which goes through the edge of the sample and
the air surrounding the sample is not measured (it goes directly to earth) and
therefore does not contribute to the measurement.
D.2.4
CHANGING THE FIXED (‘LO’) ELECTRODE
1. Using the micrometer, move the travelling electrode as far away as possible
from the fixed electrode, to give access to the fixed electrode.
2. Carefully unscrew the fixed electrode assembly (central electrode, guard ring
and insulation) from the body of the sample holder, using finger pressure
only. Store the electrode safely.
3. Screw the new electrode assembly into the body of the sample holder, taking
care to keep the assembly properly aligned with the sample holder to avoid
crossing the threads. Tighten the electrode gently against the body, using
finger pressure only. DO NOT OVER TIGHTEN.
Do not attempt to disassemble the electrode assembly.
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D-5
D.3
1296 4A LIQUID SAMPLE HOLDER
“Hi” Electrode
Sample
Holder
Wall
Liquid Sample
Insulation
Guard Ring
“Lo” Electrode
Figure D-2: Electrode arrangement of the 1296 4A liquid sample holder
The 1296 4A electrodes replace the solid sample holder electrodes in the 1296 2A.
The liquid sample holder is shaped as a dish in order to be able to measure small
samples of liquid. Unlike the fixed electrode for solid samples, it is permissible
to disassemble this electrode for cleaning. It makes use of the guard ring
techniques described above.
D.3.1
USING THE 1296 4A
The upper electrode should be dipped into the liquid to make sure that air is
removed from the sample being measured.
To create a particular sample thickness, follow this procedure:
1. Zero the micrometer (as described in section D.2.2).
2. Using the micrometer, adjust the position of the upper electrode sufficiently,
then place the sample liquid into the lower dish electrode.
3. Move the upper electrode carefully towards the lower electrode until the
required sample thickness is displayed. The upper electrode is slightly
smaller than the lower dish electrode so that excess liquid can escape around
the side of the upper electrode. Do not go past the required thickness,
otherwise too much liquid will escape, and it will not be in contact with
the upper electrode.
D-6
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D.4
NORMALISATION
For optimum accuracy when using liquid or solid sample holders, you should
make use of the normalisation technique. This will reduce the errors due to
fringing, connections, etc. For a more detailed description, see Chapter 3.
There are two possible methods of normalisation: matched cell geometry, and
matched cell capacitance. Both have advantages: matched capacitance gives best
cancellation of instrumentation errors, whereas matching the cell geometry
optimises the cancellation of fringing effects. Select the one which gives you the
best results.
D.4.1
METHOD 1 - MATCHED GEOMETRY
1. Take measurements on the sample in the way described above, making a note
of the micrometer setting.
2. Remove the sample, clean the electrodes if necessary, and reset the
micrometer to the setting noted above. This will create an air gap cell with the
same dimensions as the cell used for the sample.
3. Measure the impedance of this air gap cell at the same frequencies as before,
and use this data as the normalisation data.
D.4.2
METHOD 2 - MATCHED CAPACITANCE
1. Take measurements on the sample in the way described above and note the
capacitance of the sample.
2. Remove the sample and clean the electrodes if necessary. Calculate the air
gap, d (in m.), required to create an air gap cell with the same capacitance as
the sample, using the equation:
d = Aε0/C
where A is the area of the cell (in m2), C is the required capacitance (in F), and
ε0 is the permittivity of free space (8.85419E-12 F/m)
3. Set the micrometer to the calculated air gap, measure the impedance of this air
gap cell at the same frequencies as those used for the sample measurements,
and use this data for normalisation.
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D-8
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E
129604S software for HP 4192
Contents
E.1
INTRODUCTION ................................................................................E-2
E.2
SOFTWARE INSTALLATION.............................................................E-3
E.3
INSTRUMENT CONNECTIONS .........................................................E-3
E.4
LIMITATIONS WHEN USING HP4192 ...............................................E-4
12966001/Iss BB
E-1
E-2
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E.1
INTRODUCTION
The 129604S software package is identical to the normal 1296 package, but has
additional drivers to enable it to work with Hewlett Packard’s popular HP4192
Frequency Response Analyzer (FRA). The software can also be used with any of
Solartron’s range of FRAs.
There are some system limitations imposed by the HP4192 when used with 1296,
and these are listed in section E.4. In general, however, the 1296 system uses
HP4192 functions which are identical or similar to those of Solartron FRAs.
The software cannot be used to control HP4192 connected to a 1294 Impedance
Interface.
E.2
SOFTWARE INSTALLATION
The 129604S software is supplied on a set of floppy disks.
To install the 1296 software:
1. Check that 1296 hardware is safely installed, and that the ac supply is
switched on.
2. Insert the first disk (#1) into Drive A on your PC.
3. Run: a:\setup.exe
4. Follow the on-screen instructions.
NOTE: CPU intensive screen savers can slow down or stop measurements. To
avoid this problem, the screen savers should be disabled or given a low priority.
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E-3
E.3
INSTRUMENT CONNECTIONS
Figure E-1 below shows the connections to be made between the HP4192 and the
1296.
A 50Ω feedthrough terminator should be used at the 1296 end of the connection
between the HP4192 ‘Osc’ Output and 1296’s ‘Gen’ input. If the terminator is not
installed the signals appearing at the 1296 will be double the programmed level.
This may give unpredictable results if the programmed level is >0.55Vrms, due
to possible signal overload on the HP4192 inputs.
The terminator is not required with Solartron FRAs.
1296 Dielectric
Interface
HP4192 FRA
50Ω
Osc output
Gen
Sample
Sample HI
Sample LO
Channel A
V1 HI
Ref HI
Channel B
V2 HI
Ref LO
Reference Capacitor,
if required
(e.g., 12961 Test Box)
Figure E-1: HP4192 - 1296 connections
E-4
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E.4
LIMITATIONS WHEN USING HP4192
Low frequency
The low frequency limit is 5Hz (compared to 10µHz for Solartron’s 1260).
DC Bias
DC Bias is not available. This is because the HP4192 only supports DC Bias for
impedance measurement mode, not in transfer function mode, which is required
as the signals output by the 1296 are both voltage signals.
Impedance range
The maximum impedance which can be measured is around 50GΩ. This is a
result of the 5Hz low frequency limit of the HP4192. (See Appendix A.)
Integration time
The HP4192 does not have auto-integration facilities so these are “greyed out” in
the software when using HP4192. The three available options for integration
time are selected by the software as a function of the programmed integration
time as follows:
Int. time value set
less than 0.2 seconds
between 0.2 and 1 second
more than 1 second
HP4192 Integration time selected
High speed
Normal speed
Averaged
Result reformatting
The HP4192 does not allow the user to change input channels without remeasuring. The 1296 software needs to have data from two sources, channel A
and channel B-A in order to compute the voltage and current on the sample
(together with phase information). This requires the HP4192 to take two
measurements whereas the 1260 data output can be reformatted without remeasuring.
AC amplitude
A 50Ω terminator should be used for the Oscillator output of the HP4192 (see
section E.3), and the sample voltage level programmed to less than 1.6Vrms to
avoid overloading the HP4192’s channel A and B inputs.
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E-5
E-6
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