When The On/Off State Of An External Output Cannot Be Changed; When An External Output On Signal Intermittently Turns Off - Mitsubishi Electric MELSEC iQ-RX40NC6B Application User's Manual

When the ON/OFF state of an external output cannot be changed

Check the following items in order of No.
No. Check item
1 Check whether the S MODE LED is on.
2 When the safety output is turned on, check whether the
corresponding output LED is on.
3 Check whether the safety device to which output data is set is
correct.
4 Check whether "Wiring output selection" is set to "Not used".
5 Check whether the PROGRAM RUN LED of the SIL2 Process CPU
is on.

When an external output ON signal intermittently turns off

Check item
Check whether an output dark test has been conducted.
If operation is not performed normally even after the actions described above are taken, the possible cause is
a module failure. Please consult your local Mitsubishi representative.
13 TROUBLESHOOTING
196
13.3 Troubleshooting by Symptom
Action
If the S MODE LED is not on, take action by referring to the following.
Page 194 When the S MODE LED is flashing or off
If the LED is on, there is a problem in the wiring between the external output
terminal and the external output device. Check the wiring again for any wire
break or short-circuit.
If data is set to a safety device different from the safety device assigned by the
refresh device setting, a safety output cannot be made correctly.
Check the refresh device setting, and make necessary corrections to make
the program content consistent. ( MELSEC iQ-R CPU Module User's
Manual (Application))
When "Not used" is set for "Wiring output selection", the relevant safety output
is always OFF. Change the "Wiring output selection" setting according to the
actual wiring.
If the PROGRAM RUN LED of the SIL2 Process CPU is not on, the SIL2
Process CPU may be in STOP state and the program may not be operating.
Check the RUN/STOP/RESET switch for the SIL2 Process CPU and if it is set
to STOP, change it to RUN.
Action
Check the specifications of the safety device to be used, and review the
settings for "Output dark test pulse OFF time" and "Number of pulses output
for output dark test".