Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 135

■ Operation when the block is paused or restarted
Operation when the block is paused or restart depends on the combination of the SM325 (Output mode at block stop) status,
block stop mode bit setting of the SFC information device, and step hold status.
The following table lists the operations at block PAUSE/RESTART.
Output mode Setting of block
setting at block stop mode bit
stop
SM325=OFF OFF or no setting
(coil output OFF) (immediate stop)
On
(stop after transition)
SM325=ON OFF or no setting
(coil output held) (immediate stop)
On
(stop after transition)
At restart
■ Precautions
• When the block specified with the LD instruction (Checking the status of a block) has stopped, the coil output is turned on.
Also, when the step specified with the LD instruction (Checking the status of a step) has stopped, the coil output is turned
on.
• If the block is started while the PAUSE/RESTART bit of the SFC information device is on, the initial step stops before it
becomes active. If the SET instruction (Activating a step) is executed for an inactive block, the specified step stops before it
becomes active.
• When SM325 (Output mode at block step) is on, the block can be stopped while holding the coil output. Even when SM325
is turned on and off in stopped state, the state of the coil output does not change. When a block restart request is issued,
the coil output restarts while keeping the hold state.
• If the block is stopped when SM325 is on, the coil HOLD step [SC] in the hold state keeps its state even after restart but the
step operation does not restart. To make the coil HOLD step [SC] inactive, execute the RST instruction (Deactivating a
step).
• When a stop request is issued in the action to the block, the step being executed currently is executed until it ends, and
then the stop request is executed. Therefore, when the block stop mode bit is off (immediate stop), the step being executed
does not stop even if a stop request is issued within the step. If the block stop mode bit is changed to on (stop after
transition) afterwards in the same step, a stop request is executed in stop mode after transition.
Operation
Active step other than step
that holds operation
(including SC, SE, and ST
whose transition does not
become TRUE)
Immediately after a stop request
is made, the coil output of the
action is turned off and the block
is stopped. The status remains
active.
After the transition becomes
TRUE, step end processing is
performed and simultaneously the
transition destination step
becomes active and the block is
stopped before execution of the
action.
Immediately after a stop request
is made, the block is stopped with
the coil output of the action being
held. The status remains active.
Normal operation is performed
until the transition becomes
TRUE. After the transition
becomes TRUE, step end
processing is performed and
simultaneously the transition
destination step becomes active
and the block is stopped before
execution of the action.
Returns to normal operation.
Step that holds operation
Coil HOLD step Operation HOLD
[SC] step (without
transition check)
[SE]
Immediately after a Immediately after a stop request is made, the
stop request is made, coil output of the action is turned off and the
the coil output of the block is stopped. The status remains active.
action is turned off and
the block is
deactivated.
Immediately after a stop request is made, the block is stopped with the
coil output of the action being held. The status remains active.
Coil output is off: Restarts the execution
Becomes inactive and of the action in a
restart is disabled HOLD status.
Coil output is held:
Restarts with the hold
state
Operation HOLD
step (with
transition check)
[ST]
In the hold status, the
action is restarted and
the transition is also
checked.
8 SFC PROGRAM
133
8.5 SFC Setting
8