Block Temporary Stop And Restart Methods; Block Stop Methods - Mitsubishi Electric MELSEC-Q Series Programming Manual

6.3

Block Temporary Stop and Restart Methods

This section describes the block temporary stop and restart methods

Block STOP methods

The temporary block STOP methods which can be used during SFC program execution are described below.
Block STOP methods
The methods for temporarily stopping a block during SFC program operation are shown below.
STOP Method
Block STOP by SFC control instruction
STOP by SFC information device
Block STOP timing and coil output status when STOP occurs
The STOP timing in response to a block STOP request, and the coil output status during the STOP are as shown below.
Setting of Operation
Output Mode Output at
at Block Stop Block
in PLC Stop
Parameter (SM325)
Turns OFF OFF
(coil output OFF) (coil output
Remains ON OFF)
(coil output held)
Remains ON ON
(coil output held) (coil output
held)
*1 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.
6 SFC PROGRAM EXECUTION
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6.3 Block Temporary Stop and Restart Methods
Operation Description
Using an SFC control instruction, a specified block is
temporarily stopped from an SFC program step
(operation output), or from another sequence program.
The execution of the specified block is temporarily
stopped by forcibly turning ON the "block STOP/
RESTART bit", which was set to each block as the SFC
information device, in the program or peripheral device.
Status of Operation
STOP-time
Active step other than held step
Mode Bit
(including HOLD step whose
transition condition is not
satisfied)
OFF • Immediately after a STOP request is
No setting made, the coil output of the
(immediate operation output is turned OFF and
stop) the block is stopped.
• The status remains active.
ON • Normal operation is performed until
(STOP after the transition condition is satisfied.
transition) • 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 stops immediately.
OFF • Immediately after a STOP request is
No setting made, the block is stopped with the
(immediate coil output of the operation output
stop) being held.
• The status remains active.
ON • Normal operation is performed until
(STOP after the transition condition is satisfied.
transition) • 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 stops immediately.
Remarks
Convenient for temporarily stopping operation (at error
detection, etc.) in order to correct the error by manual
operation. (The manual operation control program can be
placed at another block which is forcibly started when the
block STOP occurs.)
Convenient for confirming operation by step control at
debugging and test operations, because block
processing can be stopped from a peripheral device
without requiring a program.
*1
Held step
Coil HOLD step (SC) Operation
HOLD step
(without
transition
check) (SE)
• Immediately after a • Immediately after a STOP request
STOP request is made, is made, the coil output of the
the coil output of the operation output is turned OFF and
operation output is the block is stopped.
turned OFF and the • The status remains active.
block is stopped.
• The status becomes
inactive.
• 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.
Operation
HOLD step
(with
transition
check) (ST)