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M36 slave devices, LED indicators


M36 slave devices are equipped with 2 LEDs, a green (On) to indicate that power is supplied to the module, and a red (Error) to indicate internal errors within the module.

The state of the device is indicated by the LEDs, in accordance with the scheme shown in the table.



On (Green)

Error (Red)

No power



Power, no error



Power, internal error




The Error LED is ON if an error occurs inside the device, which causes one of the flags in the ChError.Act register to be set to TRUE. Among these flags are watchdog error and error in EEPROM memory.


For the digital modules PD 620, PD 621, PD 622, and 626, the error flags are: Service.CommonError.ChError.Act[0..7]


For the analogue modules PD 640, PD 641, and 642, the error flags are: Service.ChError.Act[0..15]


Related topics

Ordering information, PD 600-Series