E-Stop Discrepancy Error - Group 2 (Safe Inputs Active)
Beckhoff · TwinSAFE Logic FB
What does FB ESTOP Bit 9 mean?
This fault indicates a discrepancy in E-Stop input group 2, similar to 'FB ESTOP Bit 1', but specifically when the 'Safe Inputs after Disc Error' option is activated. This means that even after a discrepancy, the FB attempts to maintain a safe state for the inputs, but a persistent or critical discrepancy has occurred, preventing normal operation and requiring intervention.
Common Causes
- One input channel (e.g., X8.1) of E-Stop Group 2 is failing to remain active or properly transition when 'Safe Inputs Active' is engaged.
- Poor contact or corrosion on one of the E-Stop button's redundant contacts, leading to inconsistent signal during active states.
- Wiring fault (e.g., frayed wire, loose crimp) on one E-Stop input line for Group 2, causing intermittent signal loss.
- Internal fault within the safety controller's input circuitry for E-Stop Group 2, affecting one channel's state.
- Electromagnetic interference (EMI) causing momentary signal interruption or distortion on one active E-Stop input.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Verify the continuity of both E-Stop input lines for Group 2 from the E-Stop button to the safety controller's input terminals (e.g., X8.1, X8.2).
- 2
Observe the diagnostic status of both Group 2 input channels via the safety controller's software during both idle and active states.
- 3
Measure the voltage at the safety controller's E-Stop Group 2 input terminals (e.g., X8.1, X8.2) while the system is attempting to be active.
- 4
Inspect the E-Stop button for Group 2 for mechanical wear, debris, or damage that could impede consistent contact closure.
- 5
Check and adjust the discrepancy time parameter (e.g., P_ESTOP_ACTIVE_DISC_TIME_G2) in the safety controller if asynchronous switching is occurring.