3-2-14 Specifying The Operation Cycle - Omron SYSMAC CS Series Operation Manual

Description of Operation
Operation of the Loop
Controller when the
CPU Unit is in the
Output OFF condition

3-2-14 Specifying the Operation Cycle

When executing all
function blocks at a
common operation
cycle
The Loop Controller continues to run even if the Output OFF flag causes out-
put refreshing of the CPU Unit to stop. Note, however, that in this case con-
tacts are not output and turn OFF, and the output hold function of the Analog
Output Unit holds analog output to a specific value. For this reason, the Loop
Controller only performs internal operations, and does not perform control on
the outside.
All of the function blocks (for example, all Field Terminals and the Step Ladder
Program block) on the Loop Controller are executed cyclically.
Basically*1, all function blocks (including the Step Ladder Program block) are
executed at a default common operation cycle of one second that is set in the
System Common block (Block Model 000). In other words, at the default set-
ting, the operation cycle of all function blocks is one second, and all function
blocks are executed at every second.
For example, when all function blocks A, B, C and D in the figure below are
executed and the total execution time is less than one second, function block
execution idles until the preset 1-second operation cycle is reached, and exe-
cution is resumed from function block A as the next operation cycle.
Function block A
Function block B
Operation cycle
All function blocks
are executed
(cyclically within this
cycle) in one second
as the default.
Function block C
Function block D
Idling
(standby time)
Basically∗1, the default operation cycle (ITEM004) of all function blocks is the
system common operation cycle. (In other words, the operation cycle of each
function block is interlocked with the value set at ITEM004 of the System
Common block.) The default system common operation cycle (ITEM004) of
the System Common block (Block Model 000) is one second.
To change the system common operation cycle to a value other than one sec-
ond, set one of the following values to the system common operation cycle
(ITEM004) of the System Common block (Block Model 000).
Note: Idling is performed after
execution of function blocks
to set a constant cycle.
Section 3-2
125