Mitsubishi Q Series Programming Guide

5 - 10 5 - 10
5 SFC PROGRAM PROCESSING SEQUENCE
MELSEC-Q
5.3.2 Block execution sequence
(1) In the SFC program, the step in the active block is executed every scan.
(2) When there are multiple blocks, the blocks are processed in order of lower to higher block
numbers.
(a) In the active block, the active step in that block is executed.
(b) The inactive block is checked for a START request, and if there is a START request, the
block is activated and the step in that block is executed.
Block0 Block1
Block2
S0
S1
BLT1
S2
1) 3)
4)
5) 6)
2)
BLT2
S0
S1
S2
: Active step,
: Inactive step
t0
t1
t2
S0
S1
S2
t0
t1
t2
t0
t1
t2
The SFC program is executed in order of 1) to 6).
1): Whether block 0 is active or inactive is checked.
2): Since block 0 is active, the active step (S2) is executed.
3): Whether block 1 is active or inactive is checked.
4): Since block 1 is active, the active step (S0) is executed.
5): Whether block 2 is active or inactive is checked.
6): Since block 2 is inactive, whether the next block is active or inactive is checked.

Mitsubishi Q Series Specifications

General

Brand	Mitsubishi
Model	Q Series
Category	Control Unit
Language	English