Allen-Bradley · PowerFlex 520-series Adjustable Frequency
A malfunction in the safety input enable hardware has been detected, specifically that one of the required safety inputs (S1 or S2) is not enabled. This indicates a problem within the drive's integrated safety circuit or incorrect external safety wiring, preventing safe operation.
Click steps to track your progress.
1. Measure the voltage across safety input terminals S1 and SCOM, and S2 and SCOM (e.g., 24VDC for active, 0VDC for inactive) to confirm their state.
2. Inspect the external safety circuit for any tripped devices (e.g., E-stop button engaged, safety gate open, safety relay de-energized).
3. Verify continuity of the wiring from the external safety devices to the drive's safety input terminals (S1, S2, SCOM) using a multimeter.
4. Confirm that drive safety parameters (e.g., P33-00 "STO Enable") are configured correctly for the application (e.g., set to "Enabled" if using STO).
5. If the drive has diagnostic LEDs for safety inputs, observe their status to pinpoint which channel (S1 or S2) is not enabled.