Mitsubishi Q Series Programming Guide

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6 SFC PROGRAM EXECUTION
MELSEC-Q
6.2.2 Block END methods
The methods for ending block operations are described below.
As shown below, there are several block END methods. Choose the method which is most
suitable for the purpose at hand.
END Method Operation Description Remarks
Block END by SFC
diagram symbol
•
Block processing is ended and the block is
deactivated when the block's END step is
executed.
END ste
p
• Convenient for cycle stops at automatic
operations, etc.
•
Multiple END steps are possible within a single
block.
Block END by SFC
control instruction
•
Using an SFC control instruction, a specified
block is forcibly ended and deactivated from
an SFC program step (operation output), or
from another sequence program.
Condition
rBLm
m is the block No.
Block processing is also ended when the
rBLm
Sn instruction is used to deactivate
all the active steps of the corresponding
block.
•
Convenient for executing a forced STOP (at
emergency stops, etc.) without regard to the
operation status.
Block END by SFC
information device
• The processing of the corresponding block is
ended to deactivate it by forcibly turning OFF
the "block START/END bit", which was set to
each block as the SFC information device, in
the program or peripheral device.
•
Convenient for debugging and test operations
because block processing can be ended from
a peripheral device without requiring a
program.
POINTS
(1) A forced end to block processing is possible using a method which is different from that
used to start the block.
Example: 1) A block started by an SFC diagram symbol (Bm
, Bm ) can be ended by
an SFC control instruction (nBLm).
2) A block started by an SFC control instruction (sBLm) can be ended by
forcibly turning OFF the block START/END bit of the SFC information
devices.
(2) After block END processing is completed, the block can be restarted as shown below.
Block
When the Start conditions is
designated as “Autostart block 0”
•
After block processing is ended,
processing is started automatically
from the initial step.
Block 0
When the Start conditions is
designated as “Do not autostart
block 0”
Other than block 0
•
A
fter block processing is ended, the
block remains inactive until a
START request occurs by one of
the methods described in Section
6.2.1.

Mitsubishi Q Series Specifications

General

Brand	Mitsubishi
Model	Q Series
Category	Control Unit
Language	English