CHAPTER3 CPU MODULE OPERATION
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3.8  I/O Processing and Response Delay
3.8.1  Refresh mode
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(3) Output
The operation results of the sequence program is output to the output (Y) device memory in the CPU 
module every time program operation is performed. Then, the CPU module batch-outputs the on/off 
data in the output (Y) device memory to an output module before the start of sequence program 
operations.
•Input refresh:
Before the start of sequence program operations, the CPU module batch-reads input data (1)) from 
an input module, performs a logical OR operation with data in the GX Developer input area or data 
in the remote input refresh area, and then stores the result in the input (X) device memory.
•Output refresh:
Before the start of sequence program operations, the CPU module batch-outputs data in the output 
(Y) device memory (2)) to the output module.
•When a contact instruction for input is executed:
The CPU module reads input data (3)) from the input (X) device memory and executes a sequence 
program.
•When a contact instruction for output is executed:
The CPU module reads output data (4)) from the output (Y) device memory and executes a 
sequence program.
•When the OUT instruction for output is executed:
The CPU module stores the operation result of the sequence program (5)) in the output (Y) device 
memory.
Figure 3.3 I/O data flow in refresh mode
CPU module
CPU (operation 
processing area)
3)
4)
*3
5)
X0
Y22
Input (X) 
device 
memory
Input module 
access area
Output (Y) 
device 
memory
Input 
refresh
Network 
module
Network 
module
Input 
module
1)
Output 
refresh
2)
Remote 
input refresh 
area 
*1
GX Developer 
input area 
*2
Y20
Output 
module