Mitsubishi Q Series Programming Guide

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4 SFC PROGRAM CONFIGURATION
MELSEC-Q
4.2.5 Operation HOLD step (without transition check)
SE
An operation HOLD step (without transition check) is a step where the operation output
processing of the corresponding step continues after a transition to the next step.
However, transition processing to the next step is not executed if the transition condition is
satisfied again at the corresponding step.
(1) During normal SFC program operation, the coil ON status (switched ON by OUT instruction
when transition condition is satisfied) is automatically switched OFF before proceeding to the
next step.
When an operation output step is designated as an operation HOLD step (without transition
check), the corresponding step will remain active after a transition to the next step, and
operation output processing will continue.
After a transition, therefore, the timer continues timing.
(2) The transition conditions have been satisfied, so no transition condition check is performed
after the next step becomes active.
Therefore, no step transition (subsequent transition) will occur even if the transition conditions
for the relevant step are satisfied again.
T
ransition is not
e
xecuted again.
Step which is active due
to transition condition
being satisfied.
SE
Operation is continued
after the transition
condition is satisfied.
(T0 = 1 to 100)
oT0 K100
(3) An operation HOLD step (without transition check) becomes inactive when any of the following
occur:
(a) When the END step of the block in question is executed.
(b) When an SFC control instruction (rBLm) designates a forced END at the block in question.
(c) When the corresponding step is reset by the SFC control instruction (rBLm\Sn, rSn).
(Except when SM327 is ON)
(d) When the device designated as the block START/END device of the SFC information
devices is reset.
(e) When a reset step for resetting the step in question becomes active.
(f) When "S999" is designated at the reset step in the same block.
(g) When the SFC START/STOP command (SM321) is switched OFF.

Mitsubishi Q Series Specifications

General

I/O Points	Up to 4096 points
Communication	Ethernet, RS-232, RS-485
I/O Modules	Digital, Analog, Specialized
Programming Language	Function Block Diagram, Structured Text
Power Supply	24V DC, 100-240V AC
Operating Temperature	0°C to 55°C
Shock Resistance	147 m/s2 acceleration, 3 times in each of X, Y, and Z directions
Program Capacity	Up to 252K steps