Omron SYSMAC CS/CJ Series Programming Manual page 270

Cycle Time/High-speed Processing
Programming Example 1
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.)
Communications
Execution
Port Enabled Flag
condition
a A20200
Communications
Execution
Port Enabled Flag
condition
b A20200
A20200
c
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
MAX MAX(182) execution is started if execution
D00000
condition "a" is ON and the Communications
D00100
Port Enabled Flag is ON.
D00200
Execution condition "b" is turned ON to
SET
enable the next background instructions
b
(here, SUM(184)).
"a" is turned OFF so that MAX(182) will not
RSET
be executed the next cycle.
a
SUM(184) execution is started if
SUM
execution condition "b" is ON and the
D00002
Communications Port Enabled Flag is ON
D00100
(i.e., when MAX(182) execution has been
D00201
completed).
"b" is turned OFF so that SUM(184) will not
RSET
be executed the next cycle.
b
Execution of SUM(184) has been completed
SET
when "c" is ON and the Communications
c
Port Enabled Flag is ON.
"c" is turned ON to enable confirming the
Confirmation of
completion of
completion of SUM(184).
background
execution
Section 6-1
249