WATANABE ELECTRIC INDUSTRY AS-203A Series User manual

■Key to Warning Symbols
■Attention Symbols
(1) The application of voltage or current exceeding its maximum
allowable value to the input terminals may result in instrument
damage.
(2) The supply of power out of its allowable range may cause fire,
electric shock or instrument failure.
(3) The content of this manual may subject to change without prior
notice for product improvement.
(4) This manual is carefully prepared. However, if any question
arises, or any mistake, omission or suggestion is found in the
content of this manual, contact your nearest our sales agent.
(5) Keep this manual, available easily anytime.
１.Outline
The Model AS-203A digital scaling meter is an extremely small 31/2
digit display scaling meter with the scaling function which enables
input signal to be displayed as its corresponding process variable.
This meter is designed to be highly reliable using custom LSI. AS
its power supply, an isolated voltage of 5V DC or 24V DC is
available.
As its instrumentation input signals, both 1 to 5V DC and 4 to 20mA
DC are available which, can be internally selected. In addition
to the avobe input signals, other input signals are also available.
2.Specifications
Prior to factory shipment, the meter is adjusted so that it
displayes about 1000 for the fullscale input.
●DC voltage measurement
Model No.
Range Code
Measuring
range
Display
Input
impedance
Max.
allowable
input voltage
AS-203A-1V
1 to 5V
Offset ±1000
Fullscale
100 to 1999
Approx
1MΩ
±250V
Accuracy:±(0.1% of rdg +2digit)(23℃±5℃35 to 85% RH)
●DC current measurement
Model No.
Range Code
Measuring
range
Display
Input
resistance
Max.
allowable
input current
AS-203A-2A
4 to 20mA
Offset ±1000
Fullscale
100 to 1999
51Ω
±70mA
Accuracy:±(0.1% of rdg +2digit)(23℃±5℃35 to 85% RH)
●DC voltage measurement
Model No.
Range code
Measuring
range
Display
Input
impedance
Max.
allowable
input
voltage
AS-203A-11
±199.9mV
Offset±1000
Fullscale
100 to 1999
100MΩ
±100V
AS-203A-12
±1.999V
100MΩ
±250V
AS-203A-13
±19.99V
10MΩ
±250V
AS-203A-14
±199.9V
10MΩ
±500V
Accuracy:±(0.1% of rdg +2digit)(23℃±5℃35 to 85% RH)
●DC current measurement
Model No.
Range code
Measuring
range
Display
Input
resistance
Max.
allowable
current
AS-203A-21
±199.9μA
Offset±1000
Fullscale
100 to 1999
1kΩ
±10mA
AS-203A-22
±1.999mA
100Ω
±50mA
AS-203A-23
±19.99mA
10Ω
±150mA
AS-203A-24
±199.9mA
1Ω
±500mA
AS-203A-25
±1.999A
※0.1Ω
±3A
Accuracy:±(0.2% of rdg +2digit)(23℃±5℃35 to 85% RH)
However, ±(0.3% of rdg +1digit)only for AS-203A-25
The internal resistor marked with ※is externally mounted.
●Model No. Configuration EX: AS-203A-2A-4
３.Common Specifications
Measuring function
：Specify one Model from among Models for
DC voltage and current measurements.
Operation method
：Double integral
Input circuit
：Single-ended type
Floating input(isolated power supply)
Input bias current
：2.0nA(Typical)
Sampling speed
：2.5 times／sec.
Noise rejection ratio
：NMR 40 dB (TYP.),50/60Hz
Temperature
characteristic
：Offset displayed-value;
(TYP.)±0.1-digit/℃
(MAX.)±0.3-digit/℃
Fullscale displayed-value;
(TYP.)±0.1-digit/℃
(MAX.)±0.3-digit/℃
Overrange warning
：”1999”flashes for input signal
exceeding the maximum display.
Fullscale variable range
：100 to 1999
Offset variable range
：±1000
Span
：2000 counts
Display
：LED(Light emitting diode)numeric
element Character height-8mm,Red
Polarity display
：”－”is automatically displayed When
the measurement result is negative.
External control
：・Scaling function:
Adjusted by the fine adjuster at the
front.
・External hold:
Signal is HOLD by connecting the HOLD
terminal with the COM terminal.
・Blanking:
Signal is HOLD by connecting the
BLANK terminal with the COM
terminal.
Decimal point
：Can be set to any position.
(By front stud pin selection)
Operating temperature/
humidity range
：0 to 50℃,35 to 85%RH
(No dew-condensing)
Power supply
：5V DC ±5%,120mA max.
24V DC ±20%,30mA max.
Power consumption
：For 5V DC; Approx. 0.45W
For 24V DC; Approx. 0.48W
Dimensions
：48(W)×24(H)×73(D)mm
Weight
：Approx. 46g(mainframe only)
Dielectric strength
：Between power terminal(0V) and input
terminal(LO);For 1 min. at 500V DC
Between input terminal(LO) and
mounting panel;For 1 min. at 1500V AC
Insulation resistance
：Between each terminal described above;
More than 100MΩat 500V DC
Accessories
：Connector 1Pc.
Instruction manual 1 copy
Standards
：IEC1010-1, EN50082-2, EN50081-2
EN IEC 63000
Setup enviroment
：Installation category Ⅱ,
pollution degree2(IEC1010-1)
Altitude
：2000m max.
DIGITAL SCALING METER
INSTRUCTION MANUAL
MODEL AS-203A Series
Caution
(3/4)
WATANABE ELECTRIC INDUSTRY CO., LTD.
Incorrect handling may cause
death or injury.
Warning
Do not disassemble or touch the interior while the
power is ON.
This may cause an electric shock.
Attention
The mark on the label indicates the measuring range
in the specification of item 2.
On the AS-203A,connect the control inputs (HPLD, Decimalpoint)
to base-isolated devies when the input signal is 70V DC or more.

４.Operation
4-1 Preparation before operation and general cautions
1)Use this meter at a temperature of 0 to 50 ℃and a relative
humidity of less than 85% RH.
Be careful with dew condensation.
2)Use this meter where there are no chemicals or gases harmful to
electrical components, nor dust.
3)Do not apply any vibration or shock to the meter.
4)Noise
a)Power supply circuit
As it is practically difficult to incorporate a perfect noise
prevention circuit into such a small device as this meter if
this meter is used where magnet switches may be activated in
the same power line or the lightning may frequently strikes,
externally use a surge absorption circuit such as line filter
or varistor for protecting the meter from excessive surge
current.
b)Shield
If noise may cause a problem, connect the 0V power terminal to
the ground or an equipment grounding terminal. If space
induction may cause a problem, it is effective to close the mold
case of the meter with a metal cover.
4-2 Mounting
1)Mounting the meter on the panel surface Make the panel cutout
as shown in Fig. 1; insert the meter into the panel cutout from
the mounting panel front; then strongly push the meter in the
mounting panel inside from the front.
2)Removing the internal board from the case Insert a screwdriver
into the hole at the bottom of the meter, then twist the blade
of the screwdriver in the hole to remove the case front panel.
Next, push out the internal board from the back while expanding
the case front.
4-3 Terminal connection
For connecting the terminals, see Fig.3
Lower connector
Caution
NC indicates a vacant terminal. However, do not use it as a
junction terminal.
Input LO and COM have the same potential.
Caution
During wiring, take the necessary measures to close each
terminal with an insulation tube.
1)Power connection
Connect power to the “POWER”terminals.
As this meter is not provided with a power supply switch, it
is ready to operate just when the power is connected to these
terminals.
2)Input signal connection
Connect input signal(DC voltage or current) between the INPUT
HI(+) and INPUT LO(-) terminals.
a)Shorten input signal wires as much as possible and separate
them from other signal wires.
b)If the meter is used at a noisy location, use a shieled 2-core
cable for input signal and connect the shield at one point
on the LO signal source side.
c)If input signal is superimposed with harmonic noise, use a
low-pass filter on the input side. However, as a response time
may be delayed by its time constant, decide its use depending
on the operating condition.
d)Do not apply voltage or current exceeding the maximum
allowable voltage or current to the input terminals.
e)There may be case where measured current input signal is
grounded, or floated. If the signal is grounded, connect it
at a low potential point as much as possible.
3)Decimal point setting
Remove the case front panel from the meter.
Set the upper S2 socket to the desired digit.
Caution
Do not touch any parts other than those specified.
4)Hold and Start
By shorting the HOLD terminal with the COM terminal(or by
setting the HOLD terminal to level”0”), the displayed value
just after shorting (or setting to level “0”) is held.
In addition, by opening these terminals( or setting the HOLD
terminal to level”1”) at the necessary timing, measurement
starts. (Positive pulse of ±5V for more than 1ms from 0V or
contact signal(open))
The minimum time required for one measurement is approx, 400ms.
As the input(LO) and COM terminals are connected but not
DC-separated nor isorated, perform control using mechanical
contact signal such as relay, switch, etc. as much as possible.
If control is performed by TTL or transistor, externally add
a circuit shown in Fig.4. (For floating input this circuit is
always necessary for isolation.)
“1”Level 3.5 to 5V, “0”Level 0 to 1.5V, Input current -0.5mA
4-4 Scaling
1)Offset display adjustment
Apply an input of 1V(or 4mA) to the input terminals, then turn
the offset adjuster until the display unit shows the desired
offset value.
2)Fullscale display adjustment
Apply an input of 5V(or 20mA) to the input terminals, then turn
the fullscale adjuster until the display unit shows the desired
fullscale value.
*Never reverse the above order for scaling adjustment.
4-5 Range change
The “A”range can be changed to the “V”range and vice varsa.
Remove the internal board from the case, then change the
position of the 2-leg shorting socket located near the
connector.
Then, make the adjustment in item 4-4.
５.Caution for maintenance
Store the meter at a storage temperature of -10℃to +70℃and a
relative humidity of less than 60% RH. If the mete is used
especially at a dusty location, occasionally remove the internal
board from the case, then remove dust accumulated on it.
(A rise in temperatures of internal parte may shorten a meter service
life.) AS the case and panel of this meter are molded by plastics,
do not remove stains from them using a volatile liquid such as
thinner.
６.Warranty
This meter is warranted for a period of one year from date of
delivery. Any defect which occurs in this period and is undoubtedly
caused by Watanabe Electric Industry faults will be remedied free
of charge. This warranty does not apply to the meter showing abuse
or damage which has been altered or repaired by others except as
authorized by Watanabe Electric Industry.
7.After-sale service
This meter is delivered after being manufactured, tested and
inspected under strict quality control.
However, if any problem does occur, contact your nearest Watanabe
Electric Industry sales agent or Watanabe Electric Industry
directly giving as much information on problem as possible.
MODEL AS-203A Series UJ-44794p (4/4)
6-16-19, Jingumae, Shibuya-ku, Tokyo 150-0001, Japan
Phone: [phone]
Homepage http://en.watanabe-electric.co.jp/
WATANABE ELECTRIC INDUSTRY CO., LTD.
ASAHI KEIKI DIVISION
6-16-19, Jingumae, Shibuya-ku, Tokyo 150-0001, Japan
Phone: [phone]
Homepage http://www.watanabe-electric.co.jp/en/
WATANABE ELECTRIC INDUSTRY CO., LTD.