Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 128

Continuous transition bit
This bit is a device or label that determines the continuous transition action when the transition becomes TRUE.
Setting the bit to on enables continuous transition and accordingly the action of the next step is executed in the same scan.
Setting the bit to OFF disables continuous transition and accordingly one step is executed every scan.
Setting
Off (no continuous transition)
On (continuous transition)
Ex.
The continuous transition bit of an SFC information device is specified.
(2)
(3)
(4)
(5)
(6)
Scan
Scan 1
Scan 2 and after
• When the continuous transition bit is set, a continuous transition is disabled while the set bit device is off and is enabled
when the bit device is on, regardless of the on/off state of SM323 (All-blocks continuous transition status). When the
continuous transition bit is not set, a continuous transition is disabled while SM323 is off and is enabled when it is on. (
Page 140 Continuous transition ON/OFF operation)
• SM324 (Continuous transition disable flag) is turned on automatically by the system at SFC program execution, but is off
during continuous transition. Use of SM324 under the AND condition in a transition disables a continuous transition.
(1)
M0
(2)
M0
(3)
M0 SM324
(4)
(5)
M0
8 SFC PROGRAM
126
8.4 SFC Information Devices
Description
When the transition becomes TRUE, the action of the transition destination step is executed in the next scan.
When the transition becomes TRUE, the action of the transition destination step is executed within the same scan.
When the transition of the steps become TRUE continuously, the actions are executed within the same scan until the
transition becomes FALSE or reaches the end step.
(1) (2) (3) (4)
1 scan
Description
After execution of the sequence program (1), steps (2) to (5) of the SFC program are executed continuously.
After execution of the sequence program (1), the action of step (2) is executed until the transition (6) becomes TRUE.
When M0 is on, one scan causes continuous transitions from steps (1) to (3).
Since SM324 is added as the AND condition to the transition (4), the transition (4) after execution of step (3)
does not become TRUE.
In the next scan, SM324 is turned on after step (3) and therefore a transition to step (5) occurs within the scan.
END
(5) (1) (5)
processing