Two-Hand Discrepancy Error - Pair 2 (Safe Inputs Active)

What does FB TWOHAND Bit 9 mean?

Similar to 'FB TWOHAND Bit 1', but specifically when the 'Safe Inputs after Disc Error' option is active for input pair 2. This means a discrepancy occurred, and although the FB is attempting to maintain a safe state for the inputs, the error persists, indicating a critical issue with the input pair that requires immediate attention and prevents operation.

• Intermittent contact or open circuit in the wiring connecting input pair 2 to the safety module (e.g., terminals X5.1, X5.2).
• Mechanical failure or contamination within the actuation mechanism of the two-hand button for input pair 2.
• Inadequate electrical isolation for input pair 2, leading to external noise coupling onto signal lines.
• Loose terminal connections for input pair 2 on the safety PLC or at the button enclosure.
• Safety module input channel failure specific to one channel of input pair 2.

Click steps to track your progress.

1. 1

   1. Verify secure connections at all terminals for input pair 2, from the buttons to the safety input module (e.g., X5.1, X5.2).

2. 2

   2. Actuate the buttons for input pair 2 and use a multimeter to verify consistent voltage levels (e.g., 24VDC active) at the respective safety input terminals.

3. 3

   3. Isolate and test the individual pushbuttons for input pair 2 for proper contact operation (NO/NC state changes) using a continuity tester.

4. 4

   4. If suspected EMI, ensure signal cables for input pair 2 are routed away from power cables and proper shielding is maintained.

5. 5

   5. After addressing the discrepancy, perform a forced safety system reset (e.g., acknowledge fault via HMI or dedicated input) to clear the 'Safe Inputs Active' state.