Omron CS1G/H-CPUxx-EV1 Programming Manual page 307

Cycle Time/High-speed Processing
Programming Example 1
Communications Port
Enabled Flag
Background instruction
processing for user
program
■
Traditional Programming without Background Execution
As shown below, processing is completed when the instruction is executed.
Execution condition
a
■
Programming with Background Execution
With background execution, the program is changed so that MAX(182) is exe-
cuted only when the specified Communications Port Enabled Flag is ON (i.e.,
only when the port is not already being used for background execution or net-
work communications). Also, input conditions are controlled with SET and
RESET instructions to ensure that processing is performed in the correct
order. (Communications port 0 is used for background execution in the follow-
ing example.)
Instruction
executed
Cycle time Cycle time
Background execution
I/O refresh
MAX(182) is executed completely as soon
MAX
as the execution condition "a" turns ON.
D00000
D00100
D00200
SUM(184) can be executed immediately
SUM
after MAX(182).
D00002
D00100
D00201
Section 6-1
Cycle time
271