Discrepancy error of the fail-safe digital inputs or the fail-safe digital outputs

What does C30770 mean?

A discrepancy error has been detected in either the fail-safe digital inputs or outputs, indicating inconsistent signals or faulty wiring. This compromises the reliability of safety-related I/O, potentially leading to incorrect safety reactions.

• Dual-channel fail-safe input (e.g., safety gate switch) channels (1 and 2) not switching within the parameterized discrepancy time (P30700).
• Wiring fault (e.g., partial short, intermittent open circuit) affecting one channel of a dual-channel F-IO pair.
• Faulty external safety device providing inconsistent signals on its redundant outputs.
• Software configuration error where single-channel F-IO is incorrectly set as dual-channel, or vice versa (e.g., P30701).
• Excessive electrical noise or inductive spikes causing momentary signal corruption on F-IO lines.

Click steps to track your progress.

1. 1

   Identify the specific fail-safe input or output pair (e.g., F-DI0/F-DI1) causing the discrepancy error, referenced by r2124.

2. 2

   Measure the voltage levels on both channels of the affected F-IO pair (e.g., X1:F-DI0 and X1:F-DI1) and observe their switching behavior simultaneously.

3. 3

   Perform a continuity test on both wires of the dual-channel F-IO from the external safety device to the inverter's terminals to detect breaks or shorts.

4. 4

   Temporarily bypass the external safety device with a known good input signal (e.g., 24VDC jumpers for F-DI) to isolate the device fault from wiring.

5. 5

   Adjust the discrepancy time (P30700) if the external device has inherent switching delays, ensuring the delay is within safe limits.

6. 6

   Verify the F-IO parameterization (P30701, P30702) matches the actual wiring and device type (e.g., 2-channel without test pulses).