Transition; Serial Transition - Mitsubishi Electric MELSEC-Q Series Programming Manual

4.3

Transition

A transition is the basic unit for comprising a block, and is used by specifying a transition condition. A transition condition is a
condition for execution to proceed to the next step, and execution proceeds to the next step when the condition is satisfied.
Type

Serial transition

Selection transition (branch/
coupling)
Parallel transition (branch/
coupling)
Jump transition
Serial transition
"Serial transition" is the transition format in which processing proceeds to the step immediately below the current step when
the transition condition is satisfied.
A maximum of 512 serial transition steps can be described in each block.
can be described. However, there is a restriction on the number of lines as indicated below depending on the SFC display
column setting.
*1 128 for the Basic model QCPU, Q00UJCPU, Q00UCPU, Q01UCPU, Q02UCPU, L02SCPU, L02SCPU-P, L02CPU, and L02CPU-P.
4 SFC PROGRAM CONFIGURATION
58
4.3 Transition
Function Outline
When the transition condition is satisfied, execution proceeds from the current step to the subsequent step.
A single step branches out into multiple transition conditions. Among those multiple transition conditions, execution proceeds
to only the step in the line where the transition condition is satisfied first.
Execution simultaneously proceeds to all multiple steps that branch from a single step. When all steps immediately before a
coupling are activated, execution proceeds to the next step when the common transition condition is satisfied.
When the transition condition is satisfied, execution proceeds to the specified step in the same block.
When transition condition "b" becomes satisfied at step "n" (operation output [A]) execution, operation output [A]
will be deactivated, and processing will proceed to step "n+1" (operation output [B]).
*1
Therefore, a maximum of 512 serial transitions (+)