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Analog Input Units Section 7-2
■ Set Data
• The Analog Input Unit will not start converting analog input values until
the set data has been written.
• Once the range code has been set, it is not possible to be changed while
power is being supplied to the CPU Unit. To change the range code, 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 the ladder can start to operate with
valid conversion data in input words.
The analog input data will be 0000 until the first conversion data is stored in
the input words.
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
Even if analog inputs are not
used, bits 15 in words n+1
and n+2 must be set to 1.
Even if analog inputs are not
used, bits 15 in words n+1
and n+2 must be 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 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
D0
0005
TIM
#0002
T0005
Always ON Flag
P_On
TIM0005 is started when the power is
turned ON. After 0.2 s (200 ms) elapses,
the TIM0005 contact turns ON and the
analog input 1 conversion data stored in
word 2 is transferred to D0.
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