Creating User Safety Sequence Program; Creating Plc Cpu Side User Safety Sequence Program - Mitsubishi Electric MELSEC Q Series Programming Manual

3 START-UP PROCEDURES

3.5 Creating User Safety Sequence Program

Always use safety signal module's signals as the input/output signals to/from safety sequence
program. If you use input signals of a general-purpose I/O module instead, safety can't be
ensured in case of Base unit's breakdown. This is because those signals don't have double-line
system.
As the comparison is performed for all safety signals, signal output status must be the same on
both PLC CPU and Motion CPU sides. So, always create sequence program having the same
logic on both sides even if only either output signal is used.

3.5.1 Creating PLC CPU side user safety sequence program

User safety sequence program controls output of safety signals. The safety cannot be ensured
with incorrect sequence program. Make sure to check the safety signal control logic.
Write the user safety sequence program to the both of Motion CPU and PLC CPU to
operate a safety circuit.
By writing the same-logic sequence program to the both CPUs, even when one CPU
failure occurs, the other CPU can be controlled the input/output signals safely.
Read this section to create the user program and write it to the PLC CPU.
The PLC CPU side user safety sequence program judges the safety signal inputs of
the PLC CPU to control the safety signal output of the PLC CPU.
(1) Devices to use
Create the PLC CPU side user safety sequence program using the I/O device of
safety signal module. Other devices as temporary memory, timer, counter, etc.
will follow the QnU series PLC CPU's specification. However, as the PLC CPU
side sequence programs for safety observation uses the devices shown in
Section 4.2, they cannot be used for the user program.
(2) User program name
Do not use user program name "SSU_CMP", "SLS_CMP", and "SNT_CMP".
These are the name of sequence programs for safety observation used in the
system.
CAUTION
CAUTION
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