Mitsubishi Electric MELSEC Q Series Programming Manual page 42

2 SAFETY OBSERVATION FUNCTION
(b) Comparison procedure of sequence programs for safety observation in 24-
hour continuous operation
24-hour continuous operation
Read PLC parameter of PLC CPU.
(By Motion CPU)
PLC CPU
PLC parameters check
OK
Read sequence programs for
safety observation.
(From PLC CPU by Motion CPU)
Compare sequence programs
for safety observation.
OK
Return to normal processing.
POINTS
(1) Do not erase or change the sequence programs for safety observation
(Program name: SSU_CMP, SLS_CMP, SNT_CMP) of PLC CPU. If erased or
changed, "Safety observation error (error code: 23)" will occur in case of 24-
hours continuous power ON status.
(2) When the sequence programs for safety observation (Program name:
SSU_CMP, SLS_CMP, SNT_CMP) is incorrect, turn the power supply OFF to
ON again. Safety is secured by reading the sequence programs for safety
observation from Motion CPU again.
NG
Safety observation error 34 occurs.
NG
Safety observation error 23 occurs.
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