LVDT Signal
Conditioner
HT98
FEATURES
FUNCTIONAL BLOCK DIAGRAM
Simple to use LVDT conditioner Moodule
Single module solution
28 pin footprint for easy prototype/production
Build on module full signal management
Wide power supply : +/- 15V
DC output proportional to position
Default excitation ~5KHz sinusoidal
Excitation voltage ~3Vrms
Operate up to 300 feet of cable
Will also interface to an RVDT
Work fine with LVDT as constant ( Va+Vb )
Linearity: 0.05% of FS
Gain drift: 50ppm/°C of FS
Offset drift: 50ppm/°C of FS
Available pins for off gain & offset trimming
APPLICATIONS
Industrial positioning measurement
Hostile enviroments measure
Non contact position sensing
Dynamic position measurement
GENERAL DESCRIPTION
HT98 is a flexible module for the conditioning of LVDT transducers.
It provide full functions for reading ratiometric LVDT, in order to
compensate for excitation and temp change. The module include
oscillator, demodulator, filter and signal amplifier.
The module allow to adjust gain and offset by means of a couple of
pin off module. On request is possible to change the frequency
excitation from 200Hz to 20KHz, also cascading is simple by synchro
on an carrier frequency for multiple modules in a system.
HT98 is a ready to run solution, in some cases is convenient esclude
any trimmers and again get precise not scaled signal.
By using two jumpers is convenient to configure the module for use
as Master or slave module respect to multiple devices.
It is an optimum solution for applications where high system
frequences, non contacting sensors and noisy enviroments are the
main needs.
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HT98 - PINOUT
JP1
Open
Closed
JP2
Closed
Open
Description
Default: Master mode, Vexc 3Vrms, Freq. 5KHz
Slave mode, Vexc and Freq. driven by master
(1) On board Trimmer for gain adjust .
For disable internal gain, remove TR3
For setting fixed gain, install R10. (Call HTS for custom applications)
Fig. 1
DIP 28 - Footprint
Pin Configuration
Pin. No. Mnemonic
Pin Description
1
OSC
Positive oscillator sinewave for primary LVDT coil
2
/OSC
Inverted phase oscillator sinewave for primary LVDT coil
3
Va+
Secondary "A" side positive LVDT coil
4
Vb+
Secondary "B" side positive LVDT coil
5
VaSecondary "A" side negative LVDT coil
6
VbSecondary "B" side negative LVDT coil
7
NC
Not connected.
8
LEV2
Vexc. imposed from master (see application diagram - Fig. 2)
9
LEV1
Vexc. imposed from master (see application diagram - Fig. 2)
10
Vout
Analog output resulting from LVDT conditioned
11
Ext_gain External pin for gain set (see application diagram - Fig. 2)
12
Vee
Negative power supply. typically -15V
13
Gnd
Reference Ground system
14
Vcc
Positive power supply. typically +15V
15
Off1
External pin for offset adjust (see application diagram - Fig. 2)
16
Off2
External pin for offset adjust (see application diagram - Fig. 2)
17,18,19
Gnd
Reference Ground system
ABSOLUTE MAXIMUM RATINGS
Total Supply Voltage +Vcc to -Vee .............................+36V
Storage Temperature Range .................. -65°C to +150°C
Operating Temperature Range .................... 0°C to +70°C
Power Dissipation up to +65°C ...................................1.2 W
Derates Above + 65°C ........................................... 12 mW/°C
HT98-SPECIFICATION
(Conditions: Vee = -15V, Vcc = +15V, @ +25°C , RG = 80K, Freq = 2.5KHz)
Parameter
OVERALL ERROR
TMin to TMax
SIGNAL OUTPUT CHARACTERISTICS
Output Voltage Range (TMin to TMax )
Output Current
(TMin to TMax )
Short Circuit Current
Continue...
Min
Typ
Max
Unit
0.6
2.35
% of FS
+/- 11
8
20
V
mA
mA
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Continued
Parameter
Min
Nonlinearity (TMin to TMax )
Gain Error
Gain Drift (with on module trimmer (1) )
Offset
Offset Drift
Power Supply Rejection (+/- 12V to +/- 18V)
PSRR Gain (TMin to TMax)
PSRR Offset (TMin to TMax)
300
100
EXCITATION OUTPUT CHARACTERISTICS (@ 2.5KHz)
Excitation Voltage Range
Excitation Voltage
Excitation Voltage TC
Output Current
Frequency
Frequency TC
Frequency Error
Typ
Max
Unit
75
0.4
200
0.3
200
+/- 500
+/- 1
ppm of FS
% of FS
ppm/°C
% of FS
ppm/°C
+/- 1
100
15
2.1
2.3
3.0
600
ppm/V
ppm/V
24
3.2
Vrms
Vrms
ppm/°C
mA rms
KHz
ppm/°C
%
3.5
Vrms
KOhm
KHz
µΑ
30
5
200
5
SIGNAL INPUT CHARACTERISTICS
Signal Voltage Range
Input Impedence
Input Frequency
Input Bias Current (Ain and Bin )
0.1
200
0
20
4
POWER SUPPLY REQUIREMENTS
Dual Supply Operation (For +/- 10V Output)
Current (No Load, TMin to TMax)
+/- 13
3.5
16
V
mA
TEMPERATURE RANGE
0
+70
°C
1) For external trimming, TC and error gain can change in respect to TC of resistors
OUTLINE DIMENSIONS
38 mm
20 mm
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Fig. 2
H.T.S. Via Delle Camelie, 3 - Verdellino (BG) -- Fax 035.19964337 | Site: www.htsitaly.com -- e-mail: info@htsitaly.com
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