Mitsubishi Q Series Programming Guide

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4 SFC PROGRAM CONFIGURATION
MELSEC-Q
4.5.4 Block STOP mode bit
The block STOP mode bit setting determines when the specified block is stopped after the block
STOP/RESTART bit switches ON, or after a stop designation by the block STOP instruction
(PAUSE BLm).
(1) The stop timing for a block where a STOP request has occurred varies according to the
ON/OFF setting of the block STOP mode bit, as shown below.
OFF
• The block is stopped immediately when the block STOP/RESTART bit switches from OFF
to ON, or when a block STOP instruction is executed. However, if the block
STOP/RESTART bit is switched ON within the current block, the STOP will occur when that
block is processed at the next scan, or when the instruction is executed.
ON
• The block is stopped at the step transition which occurs when the transition condition for the
current step (active step) is satisfied. However, the operation output will not be executed for
the step following the transition.
• When multiple steps are active in a parallel branch, the STOP will occur sequentially at each
of the steps as their transition conditions are satisfied.
However, the held step stops immediately after a STOP request independently of the block
STOP mode.
(2) When the corresponding block is stopped, the stop timing is as described below.
Operation
Held step *
Setting of
Output Mode at
Block Stop in
PLC Parameter
Operation
Output at
Block Stop
(SM325)
Status of
STOP-time
Mode Bit
Active step other than held step
(including HOLD step whose transition condition
is not satisfied)
Coil HOLD step (SC)
Operation HOLD
step (without
transition check) (SE)
Operation HOLD
step (with transition
check) (ST)
OFF or no
setting
(immediate
stop)
• Immediately after a STOP request is made,
the coil output of the operation output is turned
OFF and the block is stopped.
• The status remains active.
• Turns OFF
(coil output
OFF)
• Remains ON
(coil output
held)
• OFF
(coil
output
OFF)
ON
(STOP after
transition)
• Normal operation is performed until the
transition condition is satisfied.
• When the transition condition is satisfied, the
end processing of the corresponding step is
performed.
At the same time, the transition destination
step becomes active and the block is stopped
before execution of the operation output.
• Immediately after a
STOP request is
made, the coil
output of the
operation output is
turned OFF and the
block is stopped.
• The status
becomes inactive.
• Immediately after a STOP request is
made, the coil output of the operation
output is turned OFF and the block is
stopped.
• The status remains active.
OFF or no
setting
(immediate
stop)
• Immediately after a STOP request is made,
the block is stopped with the coil output of the
operation output being held.
• The status remains active.
• Remains ON
(coil output
held)
• ON
(coil
output
held)
ON
(STOP after
transition)
• Normal operation is performed until the
transition condition is satisfied.
• When the transition condition is satisfied, the
end processing of the corresponding step is
performed.
At the same time, the transition destination
step becomes active and the block is stopped
before execution of the operation output.
• Immediately after a STOP request is made, the block is stopped
with the coil output of the operation output being held.
• The status remains active.
*: The held step indicates the step whose attribute has been set to the HOLD step (SC, SE, ST) and which is being held with the
transition condition satisfied.

Mitsubishi Q Series Specifications

General

Brand	Mitsubishi
Model	Q Series
Category	Control Unit
Language	English