Mitsubishi Q Series Programming Guide

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4 SFC PROGRAM CONFIGURATION
MELSEC-Q
4.2 Steps
Steps are the basic units for comprising a block, and each step consists of operation outputs.
(1) The following table indicates the number of steps that can be used in one block.
CPU Module Type
Maximum Number of Steps in
One Block
Maximum Number of Steps in
All Blocks
Basic model QCPU
Universal model
QCPU
Q02UCPU
128 steps 1024 steps
High Performance model QCPU
Process CPU
Redundant CPU
Universal model
QCPU
Q03UDCPU, Q04UDHCPU
Q06UDHCPU, Q13UDHCPU
Q26UDHCPU, Q03UDECPU
Q04UDEHCPU, Q06UDEHCPU
Q13UDEHCPU, Q26UDEHCPU
512 steps 8192 steps
(2) Serial step numbers are assigned to the steps in creation order at the time of SFC program
creation.
The user can specify the step numbers to change them within the range of the maximum
number of steps in one block.
The step numbers are used for monitoring the executed step and for making a forced start or
end with the SFC control instruction.
4.2.1 Step (without step attribute)
During processing of steps without attributes, the next transition condition is constantly monitored,
with transition to the next step occurring when the condition is satisfied.
(1) The operation output status of each step (n) varies after a transition to the next step (n + 1),
depending on the instruction used.
(a) When the OUT instruction is used (excluding OUT C
)
When a transition to the next step occurs and the corresponding step becomes inactive,
the output turned ON by the OUT instruction turns OFF automatically.
The timer also turns OFF its coil and contact and also clears its present value.
Step “n”
Step “n+1”
Transition
condition “n”
Example:
oY0
When transition condition “n” becomes satisfied at the
step “n” operation output where Y0 is ON (in
accordance with the OUT instruction), Y0 is
automatically switched OFF

Mitsubishi Q Series Specifications

General

Brand	Mitsubishi
Model	Q Series
Category	Control Unit
Language	English