E-Stop Discrepancy Error - Input Group 1

What does FB ESTOP Bit 0 mean?

A discrepancy has been detected between the two channels of input group 1 for the FB ESTOP. This indicates that the redundant E-Stop input signals are not in agreement, suggesting a potential failure of one channel, a wiring issue, or an incorrect switching sequence. This will prevent the E-Stop function from operating safely and halt the machine.

• One channel of the redundant E-Stop button's normally closed (NC) contact is mechanically stuck open or closed.
• Wire break or high resistance connection in one signal path from the E-Stop device to the safety controller input (e.g., input X1.1).
• Insufficient input debounce time parameter (e.g., P_ESTOP_DBNC) in the safety controller configuration allowing transient noise to cause discrepancy.
• External electromagnetic interference (EMI) disrupting one E-Stop input channel, causing momentary signal loss.
• Aging or worn contacts within the E-Stop button itself, leading to asynchronous switching.

Click steps to track your progress.

1. 1

   De-energize the safety circuit and measure continuity across both NC contacts of the E-Stop button while pressed and released (e.g., between terminals S11 and S12, and S21 and S22).

2. 2

   Visually inspect the E-Stop button contacts and associated wiring for physical damage, corrosion, or loose terminal connections (e.g., terminals IN_G1_CH1, IN_G1_CH2).

3. 3

   Perform an insulation resistance test on each E-Stop cable conductor from the button to the safety controller input terminals.

4. 4

   Verify the input debounce time parameter (e.g., P_ESTOP_DISCREPANCY_TIME) in the safety controller; increase it if transient discrepancies persist.

5. 5

   Monitor the status of both input channels (e.g., via diagnostic software or LEDs on the safety controller) while actuating the E-Stop button.