Minebea DSA-631 User manual

Dynamic Strain Amplifier
DSA-631
INSTRUCTION MANUAL
EN294-1320-E

I
INTRODUCTION
▲Before Using▼
We would like to express our thanks to you for your purchase of our product, dynamic
strain amplifier DAS-631. Please read this manual carefully before operating this
instrument.
This manual provides the information necessary to operate the instrument safely. This
manual covers basic functions and operations of the DAS-631 amplifiers and handling
precautions. Place this manual within reach of the DAS-631 amplifier. If you encounter
any problem in the manuals, please contact our representative.
▲Examining Contents in Package▼
If opening the package in a warm room during the cold season, open the package after it
has reached room temperature to avoid any operational failure due to condensation on the
surface of the product.
The warranty does not apply for the case where damages or faults caused by use against
instructions, warnings, or cautions.
This instrument is delivered after a thorough examination at the factory prior to shipment.
However, please examine the product's condition and verify that no obvious shipping
damage has occurred after opening the package. Also, examine the specifications of the
input units and accessories. If there are any missing or damaged items, please contact our
sales representative.
▲Cautions▼
●The contents of this manual are subject to change without notice.
●This manual is copyrighted with all rights reserved. No parts of this manual may be
transcribed or reproduced without written permission.
●Please let us know if there are any points that are unclear or missing in this manual.
●We do not assume any responsibility for the outcome of the use of DAS-631 amplifier.

II
PRECAUTIONS
To avoid accidents, read this manual carefully before use. Observe the following warning
and cautions when using amplifiers. The warranty does not apply any damage caused by
the use against instructions, warnings, and cautions. To safely use the amplifiers, the
following statements are used in this manual to call the readers' attention.
This indicates a condition or practice that could result in personal injury or loss of life, or
may result in light injury or physical damage if this equipment is misused due to neglect
of a Warning
This indicates a condition or practice that could result in light injury or damage to the
equipment or other property if this equipment is misused due to neglect of a Caution.
In order to avoid electrical shock or burning, confirm that no common mode voltage or
signal is applied to the signal wire when the signal wire is connected
W
ARNING
CAUTION

III
●POWER SUPPLY
Make sure that the power supply is within the rating. If any voltage exceeding the rated
voltage was supplied, there would be risk of damage to this amplifier, or even a fire. Also, in
order to prevent electric shock and hazards such as a fire, be sure to use only the AC power
cable and the adapter (3-prong/2-prong converter) supplied with this amplifier.
●Protective Grounding
Be sure to ground this amplifier before supplying power. Grounding is necessary to use this
amplifier safely, as well as to protect the user and peripheral equipment from injury or
damage. Be sure to observe the following instructions:
1) Protective grounding
This product uses a 3-pole power cable, which has grounding. Always connect to the power
outlet having grounding. If using 3-prong/2-prong adapter, secure the grounding by
connecting either a protective terminal or a grounding lead extending from the adapter.
2) Caution on protective function
While the power is supplied to the amplifier, do not cut or remove the protective grounding
line. Otherwise, safety of the amplifier is not guaranteed.
3) Protective function failure
Avoid using this product when there is a failure in protective grounding or protective
functions. Confirm that there is no failure in the protective function before using.
●Use in Gaseous Atmosphere
Never use this amplifier in a flammable or explosive atmosphere, or atmosphere of steam. Use
in such atmosphere will result in danger to users and the amplifier.
●Disassembling the Frame
It is dangerous to remove the frame. Do not remove the frame from the amplifier other than
100VAC/200VAC switching using the selection switch.
●Input Signal Connection
Connect the signal wire to the input terminal after connecting protective grounding terminal
to the ground. Please work after confirming that the signal and the common mode voltage are
not impressed to the input line when you connect the input line to prevent the shock hazard
and the accident of damaging by a fire.
●Note in operation
There is a possibility that high voltage is caused in the working of this product between the
input terminal (Input signal line) and this unit (protective grounding), or between the input
terminal and output (output signal line), etc. Therefore, please be careful enough on the
electric shock hazard with the operation.
●Installation category and pollution level of this product
This instrument is a unit used of installation category Ⅱand pollution level Ⅱ.
Please use it within this range. Please turn on the power supply of this product after
confirming the power supply is in ratings of this product without fail.
W
ARNING

IV
●Caution in handling
When using this amplifier, always follow the precautions below.
1) Limitation of operator
Users who are not familiar with the operation of this recorder should avoid using it.
2) Use and storage environment
The storage temperature and humidity of the input units is -20 to 70C and 10 to 90%,
respectively. Avoid storing in places where the temperature could rise over the storage
temperature and where there is direct sunlight exposure such as inside an automobile.
Do not use this recorder at the following locations.
①Locations where the temperature and humidity rise due to direct sunlight or heaters.
(The operating environment of the amplifier; temperature: -10 to 50 °C, humidity: 20 to 85%)
②Wet locations
③Locations where salt, oil, or corrosive gases exist
④Damp or dusty locations
⑤Locations subject to strong vibrations
3) Cautions on power supply
①Be careful of power voltage fluctuations. Do not use the amplifier when these are likely to exceed the
rated voltage.
②If the power supply includes a lot of noise or high-voltage inductive noise, use noise filters to avoid
operation errors.
CAUTION

V
CAUTION IN HANDLING
Read this manual carefully before using the amplifier.
1) Do not apply neither voltage nor current to the output terminal of this amplifier from
external source.
2) Use this amplifier with power supply voltages from 85 VAC to 132 VAC, 180 VAC to 264 VAC,
or 10 VDC to 30 VDC. The AC power supply selection switch is provided inside the chassis.
To switch the AC power supply voltage, refer to page 42.
●When this amplifier is used in Japan domestic, the voltage that exceed power supply
voltage AC125 V cannot be supplied from the limitation of Electrical Appliances and
Material Safety Law.
If the power fuse is burnt, check the cause of fuse blow-out. To replace the fuse, always
disconnect the power plug and input/output signal cable first, and then replace the fuse in
the fuse holder. For how to replace fuse, see page 41. When replacing, examine the ratings of
fuse (e.g. for AC or DC).
3) The storage temperature and humidity of the input units is -10 C to 50 C and 20 % to 85 %,
respectively. If opening the package in a warm room during the cold season, open the package
after it has reached room temperature to avoid any operational failure due to condensation
on the surface of the product.
Do not use this recorder at the following locations.
①- High-humidity locations
②- Locations with direct sunlight exposure
③- In the vicinity of high-temperature heat source
④- Location with vibrations
⑤- Locations where salt, water, oil, or corrosive gases exist
4) When using many amplifier units, install fan units.
5) When a case is used to accommodate amplifiers, the case must be grounded.
6) This product uses a flash memory for saving setup values. Replacement of battery is not
needed accordingly.
7) As the DSA-631 have AC signal bridge voltage. Amplifier unit whose bridge voltage
frequency differs cannot be used in the same case. In addition, when using several units
closely, always make synchronization. Otherwise, noses may be generated. See 3-8 and 3-9
for details.
8) This amplifier unit uses rotary encoders are used for knobs to control functions. However,
indication position of the knob sometimes stays at the position between scale markings. In
such case, the settings upon power-up may differ from those upon turning off the amplifier.
To avoid such event, it is recommended to allow knob indication to be at the correct scale
marking position.

VI
WARRANTY
We ship our products after conducting quality control, which covers from design to
manufacturing. It is, however, possible that failures may occur in the products. If the product
does not operate correctly, please make a check of the power supply, cable connections, or other
conditions before returning this product to us. For repair or calibration, contact our sales agency.
Before returning, be sure to inform us of the model, serial number, and problematic points. The
following is our warranty.
LIMITED WARRANTY
1) Warranty period : one year from our shipment.
2) Warranty limit
We will repair the defects of our product free of charge within the warranty period; however,
this warranty does not apply in the following cases.
①Damage or faults caused by incorrect use.
②Damage or faults caused by fire, earthquake, traffic accident, or other natural disasters.
③Damage or faults caused by a repair or modification that is carried out by someone other than our
service representative.
④Damage or faults caused by use or storage in environmental conditions that should be avoided.
⑤Periodical calibration.
⑥Damage or faults caused during transportation.
3) Liability : We do not assume any liabilities for equipment other than us.

VII
TABLE OFCONTENTS
INTRODUCTION ..........................................................................................................................................................................I
PRECAUTIONS ........................................................................................................................................................................... II
CAUTION IN HANDLING .......................................................................................................................................................... V
WARRANTY ................................................................................................................................................................................VI
LIMITED WARRANTY ...............................................................................................................................................................VI
TABLE OF CONTENTS ........................................................................................................................................................... VII
1. OVERVIEW .......................................................................................................................................................................... １
1-1. FEATURES ............................................................................................................................................................................１
1-2. PRODUCT STRUCTURE.........................................................................................................................................................１
1-3. ACCESSORIES.......................................................................................................................................................................１
1-4. BLOCK DIAGRAM OF MEASUREMENT ................................................................................................................................２
1-5. FEATURES OF DYNAMIC STRAIN AMPLIFIER.....................................................................................................................３
2. NAMES AND FUNCTIONS OF PARTS .......................................................................................................................... ４
2-1. NAMES AND FUNCTIONS OF PARTS ON FRONT PANEL (SEE 2-1.).....................................................................................４
2-2. HOW TO SET CALIBRATION VALUE (CAL).........................................................................................................................８
2-3. INDICATION UPON BALANCING...........................................................................................................................................９
2-4. NAMES AND FUNCTIONS OF PARTS ON REAR PANEL (SEE FIG.2-2).................................................................................10
3. BEFORE MEASURING...................................................................................................................................................... 12
3-1. CABLE CONNECTIONS.........................................................................................................................................................12
3-2. OPERATION BEFORE MEASURING......................................................................................................................................13
3-3. BRIDGE CHECK FUNCTION.................................................................................................................................................15
3-4. CABLE LENGTH COMPENSATION FUNCTION ....................................................................................................................17
3-5. HOW TO SWITCH SPECIAL FUNCTION SETTING................................................................................................................19
3-6. CASE .....................................................................................................................................................................................20
4. MEASUREMENT................................................................................................................................................................ 25
4-1. CAUTIONS BEFORE MEASUREING (REFER TO TABLE 4-1)................................................................................................25
4-2. INPUT CONNECTION ............................................................................................................................................................26
4-3. CONNECTION OF OUTPUT TO LOAD ...................................................................................................................................31
4-4. HOW TO READ MEASURED VALUES ...................................................................................................................................32

VIII
4-5. SPECIAL APPLICATION ........................................................................................................................................................ 35
5. OPERATION THEORY.......................................................................................................................................................36
5-1. FLOW OF MEASUREMENT SIGNAL (REFER TO FIG.5-1)................................................................................................... 36
6. OPTIONAL FUNCTION.....................................................................................................................................................37
6-1. CURRENT OUTPUT (DSA631-P07 4~20MAOUTPUT UNIT)......................................................................................... 37
6-2. CASE FUNCTION AND TYPE ............................................................................................................................................... 37
7. MAINTENANCE..................................................................................................................................................................39
7-1. ITEMS TO BE CHECKED. ..................................................................................................................................................... 39
7-2. HOW TO REPLACE FUSE ..................................................................................................................................................... 41
7-3. CHANGING AC POWER SUPPLY VOLTAGE .......................................................................................................................... 42
8. SPECIFICATIONS...............................................................................................................................................................43
9. REFERENCES .....................................................................................................................................................................45
9-1. FREQUENCY CHARACTERISTICS AND PHASE PROPERTY ................................................................................................. 45
9-2. CABLE LIST ......................................................................................................................................................................... 46
9-3. OUTLINE DIMENSIONS ....................................................................................................................................................... 48

1
1. Overview
1-1. Features
DSA-631 is Dynamic Strain Amplifier that features new function such as cable length
compensation and bridge checking, realizing higher-accuracy and higher-quality measurement
and a reduction in measurement preparation time. This model includes an LED monitor and the
auto-balancing function, thereby improving their operability and permits strain gage type
transducers to perform physical value measurement.
By using the case, batch of power supply, automatic balancing, apply of the calculation value and
set of key lock for all channels can be execute at the same time. If there is any troublesome, please
see the paragraph of maintenance, and contact us at any time.
1-2. Product structure
The summarized specifications of dynamic strain amplifier DSA-631 is below. The sensitivity is
based on BV = 2 V.
Table 1-1. Specifications of DSA-631
DSA-631 can use the following optional devices and case.
Description Type Items Remarks
Current output DSA631-P07 OUTPUT2 : 4 ~ 20 mA output Specified upon ordering
Bench top case
AS16-104 4CH Bench case ±CAL, BAL, KEYLOCK and
batch ON/OFF for all units are
available. Possible to synchronize
with another case.
AS16-105 6 CH Bench case
AS16-106 8 CH Bench case
Rack mounting case AS16-107 8CH Rack-mount case
Table 1-3 List of optional devices
1-3. Accessories
Output cord (0311-2057) 1 piece
Time-lag fuse
(Fuse for AC power supply : AC85 ~ 132 V / AC180 ~ 264 V, 100 mA : 0334-3006 1 piece)
(Fuse for DC power supply : DC10V ~ 30V, 500 mＡ: 0334-3013 1piece)
Knurling tool screw for mounting panel 2 pieces
Driver for adjustment 1 piece
AC power cord (47326) 1 piece
Instruction manual 1 piece
Model no. BV Shape Balance Frequency Sensitivity (BV = 2 V) Main application
DSA-631 ACV Unit type Auto DC ~ 2kHz 10V/200x10-6 strain Strain measurement

2
1-4. Block Diagram of Measurement
The following diagram illustrates a typical measurement system that broadly covers a variety of
factors including signal amplitude, frequencies, and measuring time.
Fig. 1-1 Block diagram for Measuring
Oscilloscope Waveform
Data Recorder Data recording
Digital voltage meter Digital recording
Pen Oscillograph
Waveform Rec. in
Low freq. range
(DC ~ 120 Hz)
Thermal Dot
Recorder
Waveform Rec. in
High freq. range
（DC ~ 20kHz）
DAQ
Waveform Rec. in
high freq. range
（DC ~ 100kHz）
Data processor Data Analysis and
Processing
Phenena Sensor Instrument Recorder & Analyzer
Load
Pressure
Displacement
Acceleration
Tor
q
ue
Bridge bo
x
Strain gage
Strain
Dynamic strain
amplifier
(AC bridge type)
DSA-631
Sensor

3
1-5. Features of Dynamic Strain Amplifier
Bridge power
voltage supply
AC bridge type
(AC strain amplifier)
Recommended
sensor
1. Various strain gages
2. Sensors for load, displacement, acceleration and torque
(Strain gage type transducer)
Features
AC strain amplifiers have higher S/N ratio and higher sensitivity than those of DC
strain amplifiers. However, for non-linearity and frequency response, AC strain
amplifiers does not exhibit higher performance. Because the AC strain amplifiers do
not include commercial power source that may generate noises in the amplifying
range, these amplifiers have high anti-noise characteristics. This feature is
advantageous in measurement using strain a gage.
Table 1-3 Recommended Sensors and Feature
Type
AC Strain Amplifier (Isolated)
DSA-631
Voltage Sensitivity ±10 V output at 200 x10-6 strain
Non-linearity 0.1 % FS
Frequency Response DC ~ 2 kHz
Noise 2.0 x10-6 strain p-p
Maximum Gain Approx. 50,000 times
Bridge Voltage AC voltage 0.5V, 2V
Strain Gage ◎
Strain Gage type Transducer ○
Strain Measurement under the field faced
with the worrying situation of serge
voltage.
○
Long Distance between sensor and
instrument
◎
Cable length compensation function
Impact Strain ×
◎: Optimum, ○: Adequate, x : Inadequate
Table 1-4. Choice in using condition

4
2. NAMES and FUNCTIONS of PARTS
Fig. 2-1 Face of panel Fig. 2-2 Back face
2-1. Names and Functions of Parts on Front Panel (see 2-1.)
No. Name Function
①Model Model indication
②level meter (17-dot LED) This level meter monitors the output voltage of
OUTPUT1 4 The green LED at the middle
comes on when the output voltage is within
approx.±100 mV. When the output voltage exceed
±10.5 V, the LED at the over-voltage side blinks.
③Digital monitor (Four digit 1/2) This monitor digitally displays the output voltage of
OUTPUT2 5 . When OUTPUT2 level adjustment
volume (18) is turned clockwise, [10.000] is indicated
in response to an output of 10 V. In combination
with (18), 2 tons can be displayed as [2.000] when
the transducer converting 2 tons to 10 V is used. For
decimal point shift, refer to page 3-7.
Table 2-1 Front Panel : Names and Functions (1)
①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩
⑪
⑫
⑬
⑭
⑯
⑮
⑰
⑱
⑲
1
2
4
6
8
3
5
7

5
No. Name Function
④Bridge check / Cable length
compensation / Auto-balance knob
(BAL)
* See pages 16 to 18 for bridge check
and cable length compensation.
Pressing the knob performs bridge check and cable
length compensation, enabling automatic balancing
of resistors and capacitance. For details, see
paragraph 9 Indication upon Balancing.
The result of bridge check is indicated on digital
monitor (3). If there is neither disconnection nor
short, the indication of Good is made, thereby
making cable length compensation (dropout rate
indication) and auto-balancing. If there is a
disconnection or short, the problematic location is
repeatedly indicated. After confirming the location,
make repair. For more information on bridge check
function, see paragraph 15 to 16.
The capacitance balance is always offset. Whenever
this button is pressed, the resistance balance is
automatically kept accordingly.
Note : When the high-pass filter is used (High-pass
filter LED (15) illuminating), even balancing is not
performed, indication of good balance (0 V) is made.
Therefore, do not forget to perform balancing. (When
the high-pass filter is turned on, a frequency
element of 0/.5 Hz or lower including DC is deleted,
which is the state of the offset voltage cancellation.)
Resistance balance fine tuning
(R-FINE)
Turning this knob clockwise moves the output to the
positive side, while turning it counter-clockwise
moves the output to the negative side.
⑤Keylock switch
(KEY LOCK)
On/Off switching for keylock can be made by
pressing this knob for one second or longer. While in
the lock state, keylock LED (6) illuminates. In this
state, BAL (4), measuring range selection (8),
measuring range fine tuning (9), calibration value
setting (12) and filter setting (16) cannot be used.
Pressing this knob for one second or longer cancels
the lock; keylock LED (6) also comes off.
⑥Keylock ＬＥＤ This LED indicates whether keylock is effective or
not, in that light-up for lock and light-out for unlock.
⑦Bridge power voltage ＬＥＤ
(BV (V))
This LED indicates the bridge power voltage (0.5 V
or 2 V). To select, use bridge power voltage selection
switch 3 on the rear panel.
⑧Measuring range selection knob
(RANGE)
This knob is used to select the measuring range.
Turning this knob clockwise narrows the measuring
range (i.e. increasing the sensitivity). See page 14 for
measuring range. In this case, fine tuning is not
made. [Fine tuning LED (10) comes off.]
Table 2-1. Front panel : Names and Functions (2)

6
Number Name Function
⑨Measuring range fine tuning knob
(FINE)
Fine tuning is made with the knob. Turning the
knob clockwise narrows measuring range (i.e.
increasing sensitivity) and widens the range (i.e.
decreasing sensitivity). As measuring range fine
tuning knob (9) and measuring range selection
functions together, the range automatically shift
when signals exceeds the measuring range. See
measuring range LED (11). Fine tuning LED(10)
comes off upon range shift.
Speed selection
(SLOW / FAST)
Pressing this knob allows the fine tuning speed for
measurement range to switch between high speed
and low speed. Also, resistance balance fine tuning
(4) is switched between high speed and low speed.
⑩Fine tuning LED This LED comes on while fine tuning is made.
⑪Measuring range LED The LED displays measuring range from an output
of 10 V/200 000 x 10-6 strain to 10 V/200 x 10-6 strain
⑫Calibration value setup knob
(CAL((με)) 1 με＝10-6 strain)
Indicated value is calculated value based on input.
The value can be set from 1 με to 9999 με by a step
of 1 με.
Pressing the knob changes the digit for calibration
value LED (13) and turning the knob changes
values.
For further information, see page-8 “How to set
calibration value”. The value the equivalent voltage
value based on a gage factor of 2.0 and the one gage
configuration (1 mV/V = 2000 με).
⑬Calibration value LED The LED displays calibration value and setting
status (digit blinking)
⑭Calibration value application switch This switch is used to input the value that is set by
calibration value setting knob (12). Pushing toward
right inputs a plus value (tension) and pushing
toward left inputs a minus value (compression). As a
calibration value is superimposed with the input
signal to generate the output voltage, return the
position to OFF (middle) after inputting the
calibration value.
⑮High-pass filter LED This LED comes on when the high-pass filter used.
Table 2-1. Front panel : Names and Functions (3)
First digit
Second digit

7
Number Name Function
⑯ON/OFF for high-pass filter
(FILTER)
Pressing the knob allows the high-pass filter to
switch between ON and OFF. High-pass filter LED
(15) comes on for ON and it comes off for OFF.
Filter type : 2-pole Butterworth filter
Cut-off frequency : 0.5 Hz
Low pass filter setting knob
(FILTER)
This knob is used to set the low-pass filter. Turning
the knob allows the filter to be set to OFF (=W/B) or
cut off frequency. The setting information is
displayed on low pass filter LED (17).
Filter type : 4-pole Butterworth filter.
Cut-off frequencies : 10, 30, 100, 300, 500 Hz or W/B.
⑰Low-pass filter LED This LED indicates the cut-off frequency for the
low-pass filter. W/B (wideband) signifies OFF for the
low-pass filter.
⑱OUTPUT2 level control volume The output voltage for OUTPUT2 5 can be
controlled from the rating 10 V to 1 V. Control the
voltage with the attached screw driver. The output
value is indicated on the digital monitor (3). As
decimal point shifting is possible through the dip
switch on the bottom face of the amplifier unit,
digital monitor (3) can be used for an indicator. (For
how to shift the decimal point, refer to page 19.)
⑲Power switch
(POWER)
Pressing this switch supply the power to the
amplifier unit. The power is turned off by pressing
this button again.
Table 2-1. Front Panel : Names and Functions (4)

8
2-2. How to Set Calibration Value (CAL)
The indicated value is calculated value based on input. The value can be set from 1 με to. 9999 με
by a step of 1 με(=10-6). Values should be set for each digit (Figure 2-3).
Pressing calibration value setting knob (12) (Figure 2-4) illuminates the fourth digit of calibration
value LED (13). Turning the switch changes the value on (13). Even the indication is blinking, the
setting is being made.
Press the knob when your target value is indicated. In this case, blinking of (13) turns to
illuminating (value fixed), and then the third digit starts blinking. Repeat this step up to the first
digit. After the first digit comes on and then all digits illuminates, calibration value setting
completes. To change the calibration value, repeat the steps above. The value is based on the
equivalent value for gage factor 2.00 and one gage configuration. For strain gage type transducer,
set and calculate the value based on 1 mV/V = 2 000 με.
■Calibration value setting
For strain input (με)
Calibration value (CAL)
setting range Forth Digit Third Digit Second Digit First Digit
1 to 9999 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9
EX) To convert calibration value (CAL) from 2 000 με to 5 000 με.
Fig. 2-3 Calibration value (CAL)
Fig. 2-
4
The forth digit bli
Press calibration setting
knob (12).
Indication 0 at the first digit
blinks. Press (12) once as a
value change for the first
digit is not necessary.
Turn calibration setting knob
(12) to set the value to 5. Press
(
12
)
.
Four digits come on.
The setting completes. Indication 5 at the fourth digit
comes on and 0 at the third
digit blinks. Press (12) twice as
value changes for the third and
second digits are not necessary.
First Digit
Second Digi
t
Third Digit
Forth Digit

9
2-3. Indication upon Balancing
Pressing BAL knob (4) executes bridge check and cable length compensation, thus automatically
realizing both resistance balancing and capacitance balancing. While the bridge check and cable
length compensation functions are effective (ON). the following indications appear. If there is
bridge cable disconnection or short, the problematic location is indicated repeatedly on digital
monitor (3). The indication continues until the BAL knob is pressed for five seconds or longer or
the power of amplifier is turned off. Make repair following the indication.
When bridge check is not effective (OFF), the portions enclosed by broken line are omitted,
executing auto-balancing. For how to set these functions to ON or OFF, refer to paragraph 19.
How to Switch Special Function Setting.
Display bridge check
No disconnection or short
Checking AB line Checking BC line Checking CD line Checking DA line
Disconnection or short
Example of Indication : When ther are
disconnections at AB and DA on the brige.
Disconnection in
AB on bridge Disconnection in DA on bridge
Disconnection on wire A or
Repeatedly showing
until BAL knob
being pressed
No diconnection or short : Good
Display drop
 out rate
: 98.24 %
Display Cable Length
Compensation check
Bridge check : ON
Cable Length
Compensation Check : ON Auto Balance
Repair of bridge cable or
Replace sensor.
Press BAL knob (4) for
five second or longer.
Rechecking wiring.
Press BAL setting knob.
Fig. 2-5 Block diagram for balance operation

10
2-4. Names and Functions of parts on Rear Panel (See Fig.2-2)
Number Name Function
1 Input connector (INPUT) The bridge box or connector or a transducer is
connected. The connector should be an input connector
for strain measurement confirming the standards of
The Japanese Society for Non-Destructive inspection
(NDIS4102).
2 Synchronization selection switch
(OCS)
This switch is use to set the setting for bridge power
voltage circuit included in the amplifier.
ＩＮＴ : Set to be the master, using internal circuit.
EXT : Set to be a slave, allowing this unit to
synchronize with the master’s bridge power voltage
circuit.
When the amplifier is used in a stand-alone basis,
always synchronous signal is supplied through in-case
wiring. The amplifier unit whose setting is set to be
INT is the master, therefore, other units should be set
to EXT. For more details, see page-20 Synchronization
among Unit. Please connect ④OCS to ⑤GND of 6
interface connector when synchronizing it without
using the case as shown in the figure below.
3 Bridge power voltage selection switch
(BV)
Selection of power voltage applied to the bridge can be
switched (0.5 V or 20 V).
Table 2-2 Rear Panel : Names and Functions
④⌒④⌒④⌒④⌒・・・・⌒④⌒④⌒④
⑤⌒⑤⌒⑤⌒⑤⌒・・・・⌒⑤⌒⑤⌒⑤
①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩
⑪
⑫
⑬
⑭
⑯
⑮
⑱
1
2
4
6
8
3
5
7
⑲⑰
Fi-1 Face of panel Fig. 2-2 Back face