KYOWA WGA-120A User manual

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INSTRUCTION MANUAL
WGA-120A
Carrier type instrumentation amplifier
Thank you for purchasing KYOWA's product WGA-120A Carrier type instrumentation amplifier. Read
this Instruction Manual carefully in order to make full use of the high performance capabilities of the
product. Do not use the product in methods other than described in this Manual.
Generally, company names and trade names described in this Instruction Manual are trademarks or
registered trademarks of the companies.
This Instruction Manual may not be copied or reproduced, in whole or part, without consent of KYOWA.
Copyright © Kyowa Electronic Instruments Co., Ltd. All rights reserved.
The contents of the Instruction Manual are subjected to change without prior notice.
Kyowa Electronic Instruments Co., Ltd.

CONTENTS
SAFETY PRECAUTIONS (Do not forget to read the safety precautions prior to use.)...................1
1. CONTROLS AND INDICATORS...........................................................................................13
2. INITIAL SETTINGS..............................................................................................................16
2-1 TO CHANGE JUMPERS (MANUAL BALANCE MODEL)..............................................17
2-2 TO CHANGE JUMPERS (AUTO BALANCE MODEL) ...................................................18
2-3 EXAMPLE OF CHANGING JUMPERS...........................................................................25
3. CONNECTION......................................................................................................................28
3-1 TO FIX THE WGA-120A..................................................................................................28
3-1-1 To mount the WGA-120A onto the panel.....................................................................28
3-1-2 To mount the WGA-120Aonto the DIN rail.................................................................29
3-2 TO CONNECT POWER SUPPLY ....................................................................................30
3-3 TO CONNECT TRANSDUCERS......................................................................................32
3-4 TO CONNECT TRANSDUCERS IN PARALLEL.............................................................32
3-5 TO USE STRAIN GAGES ................................................................................................34
3-6 TO CONNECT THEAUTO BALANCE CONTROLINPUT TERMINAL ........................36
3-7 TO CONNECT THE OUTPUT TERMINAL.....................................................................37

4. OPERATION PROCEDURES................................................................................................38
4-1 TO TURN ON THE POWER............................................................................................40
4-2 TO ADJUST THE ZERO BALANCE................................................................................40
4-3 TO ADJUST THE SPAN ...................................................................................................41
4-3-1 By the actual load calibration .....................................................................................41
4-3-2 By the CAL ................................................................................................................44
4-4 CORRECTION REQUIRED WHENAN EXTENSION CABLE WAS USED....................50
4-5 AUTO BALANCE ADJUSTMENT ...................................................................................53
5. SPECIFICATIONS.................................................................................................................55
5-1 SPECIFICATIONS...........................................................................................................55
5-2 BLOCK DIAGRAM .........................................................................................................61
5-3 DIMENSIONS..................................................................................................................62

-1-
SAFETY PRECAUTIONS (Do not forget to read the safety precautions prior to use.)
zPRIOR TO USE
Do not forget to read the safety precautions prior to use.
Also, keep the manual within easy reach so that you can refer to it whenever necessary.
For safe use of the WGA-120A, do not forget to read the "Safety Precautions" prior to use.
Kyowa Electronic Instruments Co., Ltd. assumes no liability for any damage resulting from the user's
failure to comply with the safety precautions.

-2-
zFor safety operation of the WGA-120A, the following symbol marks are used in the Instruction
Manual.
Indicates “PROTECTIVE GROUND TERMINAL.”
Be sure to connect the GND terminal to the ground.
zFor safety operation of the WGA-120A, the following symbol marks are used in the Instruction
Manual.
Improper operation of the system may result in death or severe injury of the
operator.
Improper operation of the system may result in injury of the operator and
physical damage of the system.
△
！WA R N ING
△
！CAUTION

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△
！WARNING
zPower supply
To prevent a fire hazard, ensure that the power supply voltage specified for the WGA-120A matches the
local line voltage before turning ON the power.
The power supply voltages are described in the following.
DC model: 10.5 to 15 VDC, power dissipation 3.5 W or less
100 VAC model: 90 to 110 VAC, power dissipation 6.5 VA or less
200 VAC model: 180 to 220 VAC, power dissipation 6.5 VA or less
240 VAC model: 216 to 264 VAC, power dissipation 6.5 VA or less
zPower cable and power outlet
The WGA-120A does not have POWER switch. Before connecting power cable to the WGA-120A,
make sure the distribution board does not supply power to the power cable. Or, electricity shock hazard
or damage of the product may result.
zProtective ground
To prevent an electric shock hazards, be sure to connect the product to the ground before turning ON the
power.
When 2P parallel vinyl wire is used for power cable, always connect the GND terminal with a separate
ground wire.

-4-
zConfirmation of protective functions
To prevent electric shock hazards, when any trouble occurs in protective functions including the GND
terminal and a fuse, do not to operate the product. Furthermore, before operating the product, always
check whether error exists or not in protective functions.
zFuse
When the pilot lamp does not light up, the fuse may be blown.
When replacing the fuse with a new one, be sure to use a fuse providing the same rating (current, voltage,
type) as specified for the product. Do not use any fuse other than specified. Do not short-circuit the fuse
holder. Before replacing the fuse with a new one, disconnect the power cable.
Use the following fuse.
DC model Resettable fuse (replacements are not required.)
100 VAC model
200 VAC model Fast acting, 100mA, 250 V, Diameter: 5 mm, Length: 20 mm
240 VAC model

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zStorage and usage in gases
Do not use/store the WGA-120A in inflammable gases, explosive gases, or vapor. Using the WGA-120A
under the above environment is too risky.
zExternal connection
To prevent electric shock hazards, be sure to connect the GND terminal to the ground before connecting
the object to be measured and external control circuit to the product.
zTerminal cover
Be sure to put a terminal cover on the terminal block. Or, electric shock hazard may result.

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△
！CAUTION
zPower supply
Use the WGA-120A within the specified power voltage.
The WGA-120A has 4 types: 10.5 to 15 VDC, 100 VAC, 200 VAC, 240 VAC.
(We are able to manufacture 110 VAC model and 220 VAC model.)
PRECAUTIONS FOR USE
zNoise
Take countermeasures against noise when the input cable (between transducers and WGA-120A) is
placed near the power lines, transformers, electrical tools, motors, Walkie-talkies, etc.
zDo not use the WGA-120A in strong electromagnetic field.
Performance may be lowered and erroneous operation and troubles may result if it is used near a
telemetry system, microwave oven, electronic furnace or any other equipment generating a strong
magnetic field.
zAvoid installing sensors and WGA-120A near a welding machine.
Failure to do so will pose the risk of erroneous data, malfunction and failure.

-7-
zDo not disassemble or remodel the WGA-120A.
It may cause electric shock hazards or damage the WGA-120A. This warranty does not cover any
damaged or defective parts that results from disassembling or remodeling.
zThe output signal (voltage/current) when the transducer cable is broken.
When the transducer cable is broken, the WGA-120A may output the following output signal
(voltage/current). Therefore, take countermeasures to avoid the adverse effect, from the output signals,
on the other measuring instruments.
Output signal (voltage): Around -13 V
Output signal (current): Around 0m A
zThe output signal (voltage/current) and unbalance load
Output signal (voltage): The unbalance load should be 2k ohm or more.
Output signal (current): The unbalance load should be 500 ohm or less.
zLocation
Use the WGA-120A within temperature ranging from -10 to 50℃and within humidity ranging from 20
to 85%RH.
Do not use the WGA-120A under environment with excessive vibration or high impact, under dusty
environment, and under humid place. Or, it may lower the performance and cause troubles.
zCleaning
When the product gets dirty, clean the product with a dry soft cloth. When dust exists inside the
WGA-120A, clean it by using an air blow gun. Do not touch electronic parts.

-8-
Limited life parts and preventive maintenance
The WGA-120A consists of various electronic components and those components, if not all, have a
useful life. Using them exceeding the years specified according to each part type (useful life) may affect
the characteristics of the WGA-120A, resulting in a malfunction or a failure. You need to replace parts
with a regular preventive maintenance schedule.
Limited life parts used with the WGA-120A are as follows.
zAluminum electrolytic capacitor
The signal-noise ratio will lower due to capacity low or smoke will be emitted due to liquid leak,
resulting in a malfunction of the WGA-120A.
zEEPROM
EEPROM will results in malfunctions or degraded performance.
To operate the WGA-120A normally, finding a sign of the WGA-120A failure early by daily/periodic
inspections and taking the corrective action are required. For inspection, contact KYOWA or our
representatives. * All components do age and will fail.

-9-
WGA-120Areplacement before the end of service life
Preventive maintenance and replacement parts are a cost-effective way of keeping the performance and
extending the service life of the WGA-120A. Regardless of the replacement parts, the WGA-120A itself
gradually deteriorates with age. Before the expected service life is reached, consider replacing the
WGA-120A with a new one or the latest series as preventive maintenance.

-10-
Precautions on CE marking
zBe sure to mount the WGA-120A on the control panel, etc. Before turning ON the power, make sure
the WGA-120A is covered to avoid contact with hands.
zThe WGA-120A connection, jumper changing, BAL/CAL switch operation, adjuster operations, and
fuse replacement should be executed by experts in electrical work.
zTo immediately turn OFF the WGA-120A, place switches or circuit breakers inside the building and
near the WGA-120A and display the functions as well. Use switches and circuit breakers conforming
to the IEC60947-1 and IEC60947-3.
zUse the WGA-120A in area where elevation is 2000 m or below.
zWhen mounting the WGA-120A in your system, approaches to satisfy the CE marking requirements
vary with the configuration of the control panel to be used, the other devices to be connected, and
wirings. Therefore, customers are required to check whether the CE marking requirements on the
system are satisfied or not.
zUse shielded cables as input cables, output cables and control cables.

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Outline
The WGA-120A is a compact and light-weight carrier type instrumentation amplifier, designed to be
used for measuring load, pressure, torque, and displacement by using strain gage transducers.
Function
zZERO balance
The WGA-120A has manual balance model and auto balance model (external contact points are also
available).
zThe WGA-120A is able to change excitation voltage, output signal (voltage/current), sensitivity,
calibration value (CAL), and frequency response.
The WGA-120A is able to change characteristics by using the internal jumpers.
Standard accessories
The following accessories are packed with the WGA-120A. When unpacking, check the contents to
ensure that all accessories are enclosed.
zTest Certificate and Warranty 1 each
zInstruction Manual 1
NOTE: A power cable is not included in the accessories. Customers are required to purchase the power
cable applied for your power supply specifications.
Optional accessories
AC power cable for 100 VAC: P-23
AC power cable for 200 VAC/240 VAC: P-28
DIN rail mounting plate: EDP-70

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Model
The WGA-120A series has 8 models. Customers are required to purchase the power cable applied for
your power supply specifications.
Model Balance adjustment Power supply specs
WGA-120A-00 Manual DC
WGA-120A-01 Manual 100 VAC
WGA-120A-02 Manual 200 VAC
WGA-120A-03 Manual 240 VAC
WGA-120A-10 Auto DC
WGA-120A-11 Auto 100 VAC
WGA-120A-12 Auto 200 VAC
WGA-120A-13 Auto 240 VAC

1. CONTRO
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S AND INDICATO
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R
S

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Pilot lamp Lights up in green while the power is supplied to the
WGA-120A.
When the WGA-120A is slave unit in the synchronous operation,
the pilot lamp lights up in orange. (See “3-5 TO USE STRAIN
GAGES.”)
ZERO coarse adjuster(ZM) Coarse adjusts the ZERO of the output signal (voltage/current).
The item is not able to use on the auto balance model.
ZERO fine adjuster(ZF) Fine adjusts the ZERO of the output signal (voltage/current).
Sensitivity adjuster(SPAN) Adjusts the SPAN of the output signal (voltage/current).
BAL/CAL switch Push up the BAL/CAL switch 2 times within 0.5 seconds to
execute the auto balance adjustment. Note that the manual
balance model will not execute the auto balance adjustment. The
WGA-120A adds the CAL to the output signal (voltage/current)
while the BAL/CAL switch is pushed down.
Transducer input terminal Connects a strain gage transducer.
Output terminal[OUT+],[OUT-] Outputs signal proportional to the input signal (voltage/current),
issued from the strain gage transducer.
Synchronous terminal For synchronous operation (See “3-5 TO USE STRAIN
GAGES.”)
[OSC IN],[OSC OUT]

-15-
Auto balance control input terminal Short-circuit the AZ terminal and COM terminal 2 times within
0.5 seconds to execute the auto balance adjustment (auto balance
model only). (See “4-5 AUTO BALANCE ADJUSTMENT.”)
Power supply input terminal Power supply terminal.
Power supply varies with WGA-120A models. Carefully read
the Specifications before connecting the power supply.
Protective ground terminal GND terminal. Be sure to connect the product to the ground
before turning ON the power.