3. AIAO Units
MN05003006E F or more information visit:
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1-91
3.2.1.10 Application
Measuring Current
1. Description
y
Assume the ELC is to convert a current (-20mA ~ 20mA) analog signal into digital
signals then display the current value in D0.
y
Configure the analog input channels to mode 4, i.e. the current input mode (-20mA ~
+20mA).
2. Addresses
y
D40: average value of the input signals
y
D50: present value of the input signal
y
D0: actual value of the present measured current
3. Wiring
y
Connect the current signal to be measured to CH1 of ELCM-AN04ANNN and jumper
V+ and I+ (as shown below).
104.7K
250
-20mA~+20mA
V1+
I1+
VI1+
CH1
104.7K
AG
FE
CH1
Current Input
Shieled cable
4. Program
description
y
When the ELC goes from STOP to RUN, set CH1 to current input mode 4 (-20mA ~
+20mA) (CR#2), and set the number of samples for CH1 to 10 (CR#8).
y
Save the average value of the input signals into D40 and the present value of the
input signals into D50.
y
In the current mode for the ELCM-AN04ANNN, the value range -20mA ~ 20mA
corresponds to K-32,000 ~ K32,000. D50 is 1600 times the actual current value (i.e.
32,000/20 = 1,600). Divide the value in D50 by 1,600 and store the value obtained
into D0 which will be the actual value of the present measured current.