Omron CP1H CPU UNITS - PROGRAMMING 05-2007, Operation Manual

Page: 462 / 788

428
Analog I/O Units
Section 7-4
Reading Converted Analog Input Values
The ladder program can be used to read the memory area words where the
converted values are stored. Values are output to the next two words (m + 1,
m + 2) following the last input word (m) allocated to the CPU Unit or previous
Expansion Unit or Expansion I/O Unit.
Writing Analog Output Set Values
The ladder program can be used to write data to the memory area where the
set value is stored. The output word will be “n+1,” where “n” is the last output
word allocated to the CPU Unit or previous Expansion Unit or Expansion I/O
Unit.
Startup Operation
After power is turned ON, it will require two cycle times plus approx. 50 ms
before the first data is converted. The following instructions can be placed at
the beginning of the program to delay reading converted data from analog
inputs until conversion is actually possible.
Analog input data will be 0000 until initial processing has been completed.
Analog output data will be 0 V or 0 mA until the range code has been written.
After the range code has been written, the analog output data will be 0 V or
0 mA if the range is 0 to 10 V,
−
10 to 10 V, or 0 to 20 mA, or it will be 1 V or
4 mA if the range is 1 to 5 V or 4 to 20 mA.
Handling Unit Errors
• When an error occurs in the Analog I/O Unit, analog input data will be
0000 and 0 V or 0 mA will be output as the analog output.
If a CPU error or an I/O bus error (fatal errors) occurs at the CPU Unit and
the analog output is set to 1 to 5 V or 4 to 20 mA, 0 V or 0 mA will be out-
put. For any other fatal errors at the CPU Unit, 1 V or 4 mA will be output.
• CP-series Expansion Unit/Expansion I/O Unit errors are output to bits 0 to
6 of word A436. The bits are allocated from A436.00 in order starting from
the Unit nearest the CPU Unit. Use these flags in the program when it is
necessary to detect errors.
Programming Example
This programming example uses these ranges:
Analog input 0: 0 to 10 V
Analog input 1: 4 to 20 mA
Analog output: 0 to 10 V
MOV(021)
2
D0
Always ON Flag
P_On
T5
#0002
T5
TIM 5 will start as soon as power turns ON.
After 0.1 to 0.2 s (100 to 200 ms), the input
for TIM 5 will turn ON, and the converted
data from analog input 0 that is stored in
word 2 will be transferred to D00000.