External interlock

What does ALARM 60 mean?

An external interlock signal has been activated, causing the frequency converter to trip. This typically originates from a safety device or process control, indicating a condition that requires intervention before normal operation can resume to prevent injury or damage.

• An external safety device (e.g., E-stop button, light curtain, safety gate switch) has been activated.
• Process control interlock tripped (e.g., high-pressure switch, low-level sensor) connected to a digital input (DI).
• Break in the wiring of a normally closed (NC) interlock circuit connected to a digital input, causing an open circuit.
• PLC or external controller issued an unintended stop command via a digital input or fieldbus.
• Loss of 24VDC control power to the interlock circuit causing a fault state (if powered by an external source).

Click steps to track your progress.

1. 1

   Identify the specific digital input (e.g., DI1, DI2, DI3) configured for the interlock in P5-10 to P5-15.

2. 2

   Verify the status of all physical safety devices (E-stops, safety gates, light curtains) in the system.

3. 3

   Check continuity of the interlock wiring circuit using a multimeter, tracing from the drive terminal to the sensor/switch.

4. 4

   Inspect the wiring at the digital input terminals for loose connections or damaged insulation.

5. 5

   Examine the PLC logic or external controller output to confirm no unintended stop command is being sent.