9 PLC Setup
9-20
CJ2 CPU Unit Software User’s Manual
z Prohibiting Cyclic Refreshing of Special I/O Units:
Always disable cyclic refreshing of the Special I/O Units if an IORF(097), FIORF(225), IORD(222),
or IOWR(223) instruction is to be used to refresh the Special I/O Units in an interrupt task. If any of
the following is executed in an interrupt task when cyclic refreshing is enabled for the Special I/O
Units a duplicated refreshing error (non-fatal) will occur, and the Duplicate Error Refresh Flag
(A402.13) will turn ON.
• Refreshing I/O for the same Special I/O Unit with an IORF(097)/FIORF(225) instruction
• Reading or writing data for memory areas in the same Special I/O Unit with an
IORD(222)/IOWR(223) instruction
Precautions for Correct UsePrecautions for Correct Use
Whenever disabling a Special I/O Unit's cyclic refreshing, be sure that the I/O for that Unit is
refreshed with IORF(097) or FIORF(225) in the program at least every 11 seconds during opera-
tion. A CPU Unit service monitoring error will occur in the Special I/O Unit if it is not refreshed
every 11 seconds. (The ERH indicator and the RUN indicator on the Special I/O Unit will light.)
Special I/O Unit
CPU Unit
Special
I/O Unit
Area
The settings in the CPU Unit determine
whether data will exchange data with the
specified Special I/O Units for the 10
words allocated to each Special I/O Unit
in the CPU Unit (between CIO 2000 to
CIO 2959) during cyclic I/O refreshing.
To Next Page
Loading...
Need help?
General