Mitsubishi Electric · MELSEC iQ-R I/O Module
During an output dark test, the expected test pulses were not detected. This signifies that the output circuit did not respond correctly to a diagnostic test, potentially due to wiring faults, issues with connected devices, or an internal hardware problem.
Click steps to track your progress.
For any unused output terminals, ensure 'Not used' is selected for 'Wiring output selection'.
Identify the specific terminal experiencing the error using 'Output dark test error detection state' (Un\G1540), then inspect and adjust connected devices and wiring.
Implement measures to mitigate electrical noise, such as shielding cables or isolating power supplies.
If the error persists after noise mitigation, the module may require replacement due to a hardware failure.