Chapter 6 CPU Functions
6- 9
6.6 Direct Input/Output Operation
Refreshing I/O operates after completion of scan program. If data of I/O is changed while program is
scanned, it does not refreshed at the changed moment. Refreshed I/O data is applied after „END‟ instruction
on program.
This function may be useful when directly reading the status of input contact during program operation by
refreshing I/O by means of „IORF‟ instruction or outputting operation results to output contact.
„IORF‟ command is operated when M00000 is ON. First operand designates slot number. Second operand
designates the upper 32 bit data as mask data. Third operand designates the lower 32 bit data as mask data.
The bit to refresh set as 1 (hFF) and others set as 0 (h00) (not refreshed).
- When using IORF instruction to read/write data at expansion module, scan time increases by 2ms. So
when executing interrupt task program by external input less than 10ms or cycle time task less than 10ms,
task collision may occurs.
-For details regarding IORF instruction, refer to XGK/XGB Instructions List.
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