Wilcom
MODEL T312B
Optical Attenuation
Test Set
Operating Instructions
T312B Optical Attentuation Test Set
Operating Instructions
804-702-009
August 2007
Copyright (c) 2007 Wilcom
All Rights reserved
Wilcom reserves the right to make changes to the material contained
herein without notice and shall not be liable for errors contained
herein or for incidental, consequential damage in connection with the
furnishing, performance or use of this material.
This document may not be copied or duplicated in part or in whole for
any purpose without the express written permission of Wilcom.
i
Table of Contents
Page
General..................................................................................1
Introduction..........................................................................2
Description..........................................................................2
Connector Options..............................................................2
Bare Fiber Adapter..............................................................2
Wavelength Options........................................................... 2
Mode Filter......................................................................... 2
Test Sets vs Connectors and Reference Cables...................3
Specifications........................................................................4
Panel Controls and Connections.........................................7
General................................................................................7
Display................................................................................ 7
Function Related...................................................................7
Power Related......................................................................8
Operating Instructions.........................................................9
Maintenance.........................................................................15
Battery Replacement...........................................................15
Cleaning..............................................................................15
Fuse Replacement...............................................................15
Service and Repair...............................................................16
Warranty...............................................................................17
Figures
1. T312B Test Set..................................................................5
2. Loop Around Testing.........................................................8
3. Testing Installed Cable.......................................................13
ii
General
The information contained in this manual will cover several versions
of the Model T312B, Where differences occur, the applicable model
will be distinguished by the suffix -03, -05, -17, or other means of
identification as necessary.
NOTE: T312B-17 is a universal set and adapts to various
connector types. Accessory connectors and reference
cables are ordered separately for this set. See price list.
Description
The Model T312B Optical Attenuation Test Set is a ruggedized,
compact, lightweight, portable field tester designed to measure optical
power level or attenuation of fiber optic systems. A 3 1/2 digit LCD
display reads out the absolute power level from +3 dBm to -65 dBm
or the optical attenuation of a cable over a range of 45 dB,
The front panel ATTEN 0-ADJ and a reference cable permit direct
reading of attenuation on the LCD display. The PULL ON switch
applies power for unit operation. The BATT CHG indicator verifies
that the battery is charging. The TRANSMIT switch is a 3-position
toggle switch, TRANSMIT, OFF, TRANSMIT (MOM). The MOM
(momentary) position is suggested for battery operation to maximize
time between battery charge. The receive switch is a two-position
toggle switch, ATTEN dB/LEVEL dBm. This switch allows the LCD
to display cable attenuation or absolute power level measured at the
RECEIVE port. TRANSMIT and RECEIVE ports are provided with
dust caps to protect the lenses, The set is equipped with rechargeable
Ni-Cad batteries for field use which can be charged from 115/230
Volts, 50-60 Hz (factory voltage option).
1
Introduction
The set is supplied with a protective cover which stores the power
cable and reference fiber. To prevent battery drain, the power is
automatically shut off when the cover is closed. The cover is easily
removed when the set is in use.
Connector Options
The T312B is designed to mate with connectorized field installed
cables. A series of dash numbers identify the connector type supplied.
Example: (T312B-03, Amphenol Connector with 50/125 pm fiber.
This means that the TRANSMIT and RECEIVE port receptacles
and the 1 meter length of reference cable terminated with Amphenol
906 series connectors). An in-line bushing to mate with the system
cable under test is also supplied.
Bare Fiber Adapter
When installing fiber optic cable, the unit is used to measure spliced
lengths of bare fiber. The T312B-03 (Amphenol) may be provided
with a bare fiber adapter for the TRANSMIT and or the RECEIVE
port. The T312B-17 also may be used with the bare fiber adapter
when using 3005 adapter caps. Otheradapters can be made available
on special order.
Wavelength Options
The standard TRANSMIT wavelength for the T312B is 840 nm. For
other wavelengths, consult factory.
Mode Filter
The use of a one meter reference cable to measure attenuation may
give a pessimistic loss reading of up to 0.5 dB. The reason is the
output from the reference cable includes cladding and lossy modes
which are not present in longer lengths of fiber. The ideal condition
2
Introduction (cont.)
would be an output from the reference fiber with the modes in
equilibrium. To simulate this condilion, a mode filter can be provided
to eliminate the lossy modes. Consult factory on availability of mode
filter for individual sets.
Test Sets vs Connectors and Reference Cables
T312B-03
Amphenol Connector 906 Series
Reference Cable Included
T312B-05
W.E. L1A1 -A Connector
Reference Cable Included
T312B-17
Universal Connector accommodates all 3000 Series
accessory connectors. (The accessory connectors and
reference cables are not included consult the Wilcom
price list.
3
Specifications
Transmit Section
Source:
LED; 850 nm +I 0 nm wavelength; spectral
bandwidth of +/-40 nm.
(other sources by special order)
Level:
Adjustable from approx. -22 dBm to -15 dBm into
50 µm core reference cable.
Receive Section
PIN photodiode. Spectral response 400-1100 nm. Calibration
referenced to 850 nm, traceable to N.B.S.
Level:
dBm mode: +3dBm to -65dBm at 850 nm
dB mode: 51dB (calibrated to -14.0dBm) @ 850 nm
Accuracy:
dBm mode: +/-5% at 850 nm
dB mode: +0.5dB at 850 nm
Resolution:
0.1 dB
Reference Cable (Standard)
Length:
1 meter
Type:
50/125 µm
Numerical Aperture: 0.21
Power
Batteries:
Two rechargeable Ni-Cad batteries; 6.0 volt, 450
mAH (Gould 402038-5 or equivalent).
Continuous Operating Time:
30 hours receive only.
6 hours transmit on (at optical oulput, -20 dBm).
4
Specifications (cont.)
Battery Charge:
115 Vac, 60 Hz
230 Vac, 50 Hz (optional)
Charge Time:
Overnight (14 hours minimum full charge)
Power Indicators:
Display; LO BAT
Panel; BAT CHG LED
Environmental
Storage Temperature:
Operating Temperature:
Humidity:
Altitude:
Physical
Height:
Width:
Depth:
Weight:
-40°C to 60°C
-1 0°C to 40°C
95% at 35°C
40% at 50°C
(non-operating) 15,000 meters
6.5" (165 mm)
4.5" (114 mm)
6.0" (152 mm)
3.5 lbs. (1.56 kg)
5
Figure 1. The T312B Optical Attenuation Test Set
6
Panel Controls and Connections
General
This section describes the function of the display, switches, controls
and connectors located on the front panel of the Model T312B test
set. The front panel layout is shown in Figure 3-1.
Display
The display is a 3 1/2 digit LCD type. In the LEVEL dBm mode,
absolute optical power is indicated with reference to 0 dBm. In the
AlTEN dB mode, no sign appears in the display as attenuation is a
measurement of loss in dB of the unknown to a reference. The
resolution of the display is 0.1 dB.
When battery voltage falls below a predetermined value a LO BAT
indicator appears in the upper lefthand corner of the display. If the set
is continued in use, an automatic shut-off turns the set off to prevent
battery drain.
Function Related
The TRANSMIT switch is a three position toggle switch,
TRANSMIT-OFF-TRANSMIT (MOM). In the up position, optical
power is transmitted continuously; in the center position, the transmit
power is OFF, and in the down position, the transmit power is on
during the time the switch is held down.
The display switch is a two position toggle switch. The up position
displays AlTEN in dB and the down position LEVEL in dBm.
The ATTEN 0-ADJ pot is used to set the display to 00.0 in the ATTEN
mode with a reference cable attached between TRANSMIT and
7
Panel Controls and Connections (cont.)
RECEIVE ports. The TRANSMIT switch is set in the up position
during adjustment.
Power Related
The PULL ON switch turns the set on. When the cover is closed,
the set is automatically turned off.
The 115V AC or 230V AC (factory option) power cord plug is
located on the right side of the set. When AC power is applied, the
BATT CHG light turns on and indicates the battery is charging.
8
Operating Instructions
Power
The set is powered by internal rechargeable Ni-Cad batteries and
recharged by 115V ac or 230V ac, 50/60 Hz. The Ni-Cad batteries
are 6 volt, 450 MAH rated. Power is applied to the set by operating
the PULL ON power switch. The power cord is stored in the cover
and plugged into the recessed plug on the right side of the set.
Low battery is indicated by LO BAT designation appearing in the
upper left hand corner of the LCD display. Battery recharge occurs
when the ac power cord is plugged in. Charging takes place with or
without the power switch on. If the set is continued in use with low
battery, an automatic shut-down is activated to turn the set off. This
prevents possible cell reversal caused by deep drain of Ni-Cad
batteries. The set is reactivated when ac power is supplied as indicated
by illumination of the LCD display.
Reference Cable
Each set is provided with a one meter reference cable of the type
specified except for the T312B-17 where reference cable and
connector accessories are ordered separately. The reference cable
should have the same corelcladding diameter and numerical aperture
as the cable under test. The reason for this is to provide a common
mode of light propagation since anenuation is a log function of the
ratio of the test cable to the reference cable power level.
Loop Around Tests
General
Loop around testing is done with a single T312B test set. This is a
convenient way to measure reels of fiber
9
Operating Instructions (cont.)
optic cable or to measure installed cable with a patch cord at the far
end connecting the pair of fibers being measured. Fig. 4-1 illustrates
the connections. Measurement should be made in the direction of
transmission intended in the installed system as loss is not identical
in both directions.
Cable Reel Testing
Test Set Up
Loop around test is performed by removing the reference cable and
the optical fiber in-line bushing from the inside cover of the T312B
test set, cleaning the fiber faces with a lint free cloth and connecting
the reference cable to the TRANSMIT and RECEIVE ports. Caution:
Optics dust covers should be kept in place when the set is not in use.
Activate the PULL ON switch, set the display switch to the LEVEL
dBm position and turn on the TRANSMIT switch. The display wilt
read the optical power level available to the RECEIVE port in dBm.
NOTE: When making measurements with battery source, it is
recommended that the TRANSMIT (MOM) switch position be used.
This will extend the time between battery charges.Set the display
switch in the ATTEN dB.
Measurement
Turn off TRANSMIT switch, disconnect the reference cable from
the RECEIVE port and connect to near end of cable under test using
the in-line bushing supplied. The far end of the cable is connected to
the RECEIVE port as shown in Fig. 4-1. Clean ends of test cable
with lint free cloth prior to making connections. Turn TRANSMIT
switch on and read optical attenuation of the test cable on the LCD
10
Operating Instructions (cont.)
display. Optical power level of the far end of the cable is read on the
display by setting the display switch to the LEVEL d8m position.
Installed Cable Testing
The T312B must be field calibrated, at the test location, prior to
making a loss measurement. To calibrate the unit proceed as follows:
1. Attach the reference cable to the TRANSMIT and RECEIVE ports.
2. Select the TRANSMIT mode of operation.
3. Adjust the ATTEN / 0-ADJ potentiometer to give a 00.0 dB reading
on the display.
The T312B test set is now field calibrated and cable testing can be
performed as shown in Figure 4-2. (A craftsperson is required at each
end of the cable and voice communication must be established.) Using
two T312B test sets, the cable is tested two fibers at a time (one in
each direction). Fibers must be tested in the direction of transmission
for correct loss measurement.
Receive Only Tests
The T312B test set is useful as a power meter to measure optical
power level of system lasers or LEDs and their associated cables.
Measurements may be made at the source using a system patch cord
or at the far end of the system cable. The reference cable supplied
with the set may substitute as a patch cord. The display switch is set
in the LEVEL mode and optical power is read on the display in dBm.
11
Operating Instructions (cont.)
Bare Fiber Adapters
General
Bare fiber adapters are used during installation of fiber optic cables
to facilitate system connection to the test set. The T312B display
switch is positioned in the LEVEL mode and optical power level is
read. As eachsplice is made, the level is compared to a predicted
value to determine the acceptability of the splice and cable. The set
is used to monitor the alignment of fibers prior to splicing and
indicates maximum level when the best alignment is achieved.
LEVEL Measurement
If provided, the bare fiber adapter is attached to the RECEIVE pod.
The fiber is cleaned and stripped as recommended. Index-matching
oil is added to the fiber end which is inserted into the bare fiber
adapter The fiber is clamped in place and level read on the display
in dBm.
12
Figure 2.
Loop Around Testing
13
Figure 3.
Testing Installed Cable
14
Maintenance
Battery Replacement
Under normal use and periodic charging the batteries will provide
satisfactory operation indefinitely. Should the batteries require
replacement use the following procedure.
1. Remove four large Philips Head screws from the front panel.
2. Carefully lift the front panel assembly out of the case.
3. Remove two Philips Head screws which secure the battery holder.
4. Note polarity of batteries and replace accordingly.
5. Reinstall using the reverse procedure.
Cleaning TRANSMIT and RECEIVE ports
The Model T312B is provided with a dust cap for each port. The caps
must be in place whenever theunit is not in use to prevent foreign
material from entering the port.
Should any foreign material enter the ports, a cleaning agent that
leaves no residue must be used to remove it.
Fuse Replacement
The Model T312B has no replaceable fuse. The unit is protected by a
limiting device in the power transformer.
15
Service and Repair
1. Call Wilcom Customer Service. Support personnel will determine
if the equipment requires service, repair or calibration.
2. If the equipment must be returned to Wilcom for service, Wilcom
Customer Service will issue a Return Material Authorization (RMA)
number and the following address for return:
Wilcom
73 Daniel Webster Highway
Belmont, NH 03220
TEL (800) 222-1898 (USA only) or (603) 524-2622
FAX (603) 524-3735
www.wilcominc.com
IMPORTANT
Never send any equipment back to Wilcom without a Return
Material Authorization (RMA) number.
3. Pack the equipment in its original shipping material. Be sure to
include a statement or report fully detailing the defect and conditions
under which it was observed. Also be sure to include a contact name
and telephone number.
4. Return the equipment, prepaid, to the above address. Be sure to
write the RMA on the shipping slip. Wilcom will refuse and return any
package that does not bear the RMA.
Ordering Information
Orders for any of the Wilcom products and any of their optional
accessories should be directed to the address shown above.
16
Warranty
All products are warranted against defects in materials and workmanship. This warranty applies for a period of two (2) years from
date of delivery, except for Fiber Optic instrumentation and equipment which have a one (1) year warranty on parts and two (2) years
on labor. (The only exception in the digital testing equipment is the
D550 Shark, which has a warranty of one (1) year from date of delivery.) Wilcom's obligation under this warranty is limited to servicing
or adjusting each instrument returned to its factory within the warranty period, and to replace any components found to be defective.
If determined that the defective condition is a result of misuse or
abnormal operation, repairs will be billed.
LIMITATION OF WARRANTY
The foregoing warranties are the exclusive warranties provided by
Wilcom. Wilcom will not be liable for any special, indirect, incidental or consequential damages whatsoever resulting from loss of use,
loss of data or loss of profits arising out of or in connection with the
use or performance of the product, even if Wilcom has been informed
of the possibility of such damages in advance. All implied warranties, including without limitation warranties of merchantability and
fitness for a particular purpose, as well as warranties arising from a
course of dealing or usage of trade are expressly disclaimed.
PROPRIETARY INFORMATION
The information contained in this manual is the proprietary material
of Wilcom, and may not be reproduced, used for manufacturing purposes, or disclosed to others for any use without written permission
from Wilcom.
17