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Analog Input Units Section 7-2
â– Set Data
• The Analog Input Unit will not start converting analog I/O values until the
range code has been written.
• Once the range code has been set, it is not possible to change the setting
while power is being supplied to the CPU Unit. To change the I/O range,
turn the CPU Unit OFF then ON again.
Averaging Set whether averaging is to be used for set data. When the averaging bit is set
to 1, the average (moving average) for the past eight inputs is output as con-
version data.
Reading Analog Input
Conversion Values
Read the conversion value storage area with the ladder program. With word m
as the last input word allocated to the CPU Unit or an already-connected
Expansion Unit, the A/D conversion data will be output to the following words
m+1 to m+4.
Startup Operation After the power is turned ON, it will require two cycle times plus approximately
50 ms before the first conversion data is stored in the input words. Therefore,
create a program as shown below, so that when operation begins simulta-
neously with startup it will wait for valid conversion data.
The analog input data will be 0000 until the initial processing is completed.
Handling Unit Errors • When an error occurs in an Analog Input Unit, the analog input conversion
data becomes 0000.
15 0
1 0 0 0 0 0 0
8 7 6 5 4 3 2 1
15 0
1 0 0 0 0 0 0
8 7 6 5 4 3 2 1
0
0
Set to 1.
Set to 1.
Wd (n+1)
Wd (n+2)
Analog input 1
Analog input 2
Analog input 3
Analog input 4
Averaging
0
No
1
Ye s
Input Use
0
No
1
Ye s
Range code
Analog input signal range
−10 to 10 V
0 to 10 V
1 to 5 V or 4 to 20 mA
0 to 5 V or 0 to 20 mA
00
01
10
11
MOV(021)
2
D 0
T 5
#0002
T5
Power ON
P_On
TIM5 is started when the power is
turned ON. After 0.1 to 0.2 s (100 to
200 ms) elapses, the TIM5 contact
turns ON and the analog input 1 con-
version data stored in word 2 is trans-
ferred to DM0.
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