Muting EDM Monitoring Error - EDM1

What does FB MUTING Bit 4 mean?

An External Device Monitoring (EDM) error has been detected for the EDM1 feedback loop of the FB MUTING. This indicates a fault in the external safety output circuit (e.g., safety contactors) or its feedback path, which should confirm that the outputs have switched correctly in response to a muting event. This prevents unsafe operation if the outputs fail to respond, leading to a safety stop.

• Welded contacts on the external safety contactor (e.g., K1) monitored by EDM1 feedback loop.
• Broken wire or loose connection in the EDM1 feedback circuit (e.g., auxiliary contact 'NO' wire from K1 to safety input Y1.1).
• Auxiliary contact on the safety contactor K1 failed or is not configured as a normally closed (NC) contact when required (or NO if required).
• Insufficient current flow through the EDM1 feedback loop due to high resistance or faulty wiring.
• Safety PLC input for EDM1 (e.g., Y1.1) is faulty or damaged.

Click steps to track your progress.

1. 1

   1. Power down the system, then manually operate the safety contactor K1 and use a continuity tester to verify the correct switching of its EDM auxiliary contact (e.g., 53/54).

2. 2

   2. With power off, measure the resistance of the entire EDM1 feedback loop wiring from the safety output to the safety input (e.g., from Y1.0 to Y1.1) to detect open circuits.

3. 3

   3. Inspect the auxiliary contact block on safety contactor K1 for proper mounting and ensure it is the correct NO/NC type as per wiring diagram.

4. 4

   4. Verify that the safety contactor K1 is de-energizing completely when safety outputs are off by measuring the voltage across its coil terminals.

5. 5

   5. If configured as a dual-channel EDM, ensure both channels of the EDM1 feedback loop are properly wired and functional.