Omron CS1D DUPLEX SYSTEM - 10-2009 Operation Manual page 298

I/O Area
Immediate Refreshing
(Single CPU Systems
Only)
1,2,3...
262
In the following example, CIO 000101 is allocated to switch 1, an external
switch connected to the input terminal of an Input Unit. The ON/OFF status of
switch 1 is reflected in CIO 000101 once each cycle.
Switch 1
When the immediate refreshing variation of an instruction is specified by
inputting an exclamation point just before the instruction, and the instruction's
operand is an input bit or word, the word containing the bit or the word itself
will be refreshed just before the instruction is executed. This immediate
refreshing is performed in addition to the normal I/O refreshing performed
once each cycle.
Note Immediate refreshing will be performed for input bits allocated to Basic I/O
Units only (excluding C200H Group-2 High-density I/O Units and Basic I/O
Units mounted in Remote I/O Slave Racks), not High-density I/O Units which
are Special I/O Units.
1. Bit Operand
Just before the instruction is executed, the ON/OFF status of the 16 I/O
points allocated to the word containing the specified bit will be read to the
PLC.
2. Word Operand
Just before the instruction is executed, the ON/OFF status of the 16 I/O
points allocated to the specified word will be read to the PLC.
In the following example, CIO 000101 is allocated to switch 1, an external
switch connected to the input terminal of an Input Unit. The ON/OFF status of
switch 1 is read and reflected in CIO 000101 just before !LD 000101 is exe-
cuted.
Ladder symbol Mnemonic
000101 LD 000101
CPU Unit
Input Unit
Bit allocation
Once
each
cycle
Section 8-3
CIO 000101