Delta AH500 - Explanation of I;O Refreshing Instructions

AH500 Programming Manual
6-152
6.7.2 Explanation of I/O Refreshing Instructions
API Instruction code Operand
Function
0600 REF P
D, n
Refreshing the I/O
Device
X Y M S T C HC D L SM SR E PR K 16# “$” DF
D
   
n
       
Pulse instruction
16-bit instruction (5 steps)
32-bit instruction
AH500 AH500
－
Symbol:
D
：
I/O point whose state is refreshed Bit
n
：
Number of I/O points whose states
are refreshed
1~256
Explanation:
The I/O states are not refreshed until the instruction END is executed. When the scanning of the
program starts, the states of the external inputs are read and stored in the memory. After the
instruction END is executed, the states of the outputs in the memory is sent to the output terminals.
Therefore, users can use this instruction when they need the latest I/O data in the operation
process.
Example 1:
When X0.0 is ON, the PLC reads the states of the inputs X0.0~X0.15 immediately. The input signals
are refreshed without any delay.
Example 2:
When X0.0 is ON, the output signals from Y0.0~Y0.7 are sent to the output terminals. The output
signals are refreshed immediately without the need to wait for the execution of the instruction END.
Additional remark:
1. If D+n-1 exceeds the device range, the instruction is not executed, SM0 is ON, and the error
code in SR0 is 16#2003.