Steps; Step (Without Step Attribute) - Mitsubishi Electric MELSEC-Q Series Programming Manual

4.2

Steps

Steps are the basic units for comprising a block, and each step consists of operation outputs.
• The following table indicates the number of steps that can be used in one block.
CPU module type
Basic model QCPU
High Performance model QCPU
Process CPU
Redundant CPU
Universal model QCPU
LCPU
*1 For the Universal model QCPU whose serial number (first five digits) is "12051" or earlier, the maximum number of steps for all blocks is
8192.
*2 For the modules whose serial number (first five digits) is "15101" or earlier, the maximum number of steps is 8192 for all blocks.
• 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.

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.
Output status after a transition to the next step
The operation output status of each step (n) varies after a transition to the next step (n + 1), depending on the instruction
used.
■When the OUT instruction is used (excluding oC)
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.
4 SFC PROGRAM CONFIGURATION
42
4.2 Steps
Q00UJCPU, Q00UCPU, Q01UCPU, Q02UCPU
Q03UDCPU, Q03UDVCPU, Q03UDECPU,
Q04UDHCPU, Q04UDVCPU, Q04UDEHCPU,
Q06UDHCPU, Q06UDVCPU, Q06UDEHCPU,
Q10UDHCPU, Q10UDEHCPU, Q13UDHCPU,
Q13UDVCPU, Q13UDEHCPU, Q20UDHCPU,
Q20UDEHCPU, Q26UDHCPU, Q26UDVCPU,
Q26UDEHCPU, Q50UDEHCPU,
Q100UDEHCPU
L02SCPU, L02SCPU-P, L02CPU, L02CPU-P
L06CPU, L06CPU-P, L26CPU, L26CPU-P,
L26CPU-BT, L26CPU-PBT
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.
Maximum number of steps in
one block
128 steps
512 steps
128 steps
512 steps
128 steps
512 steps
Maximum number of steps
for all blocks
1024 steps
8192 steps
1024 steps
*1
16384 steps
1024 steps
*2
16384 steps