E-Stop Discrepancy Error - Input Group 4

What does FB ESTOP Bit 3 mean?

A discrepancy has been detected between the two channels of input group 4 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.

• A wiring fault (e.g., open circuit or short to ground) on one channel of the E-Stop input for Group 4.
• Mechanical binding or debris preventing one side of the E-Stop button's redundant contacts from operating freely.
• High resistance in one of the cable conductors supplying the E-Stop input, causing a voltage difference across channels.
• Input filtering parameters (e.g., P_INPUT_FILTER_G4) set too aggressively, ignoring legitimate input changes.
• Faulty E-Stop switch, where one redundant contact is intermittently failing to make proper connection.

Click steps to track your progress.

1. 1

   De-energize and check the resistance of both redundant E-Stop input lines from the device to the controller (e.g., from E-Stop button to terminals X4.1 and X4.2).

2. 2

   Verify the physical operation of the E-Stop button for Input Group 4, ensuring both contacts actuate smoothly and simultaneously.

3. 3

   Measure the voltage level on both E-Stop input channels at the safety controller during both active and inactive states.

4. 4

   Inspect all connections for Input Group 4, ensuring terminal screws are tightened to specified torque and no corrosion is present.

5. 5

   Temporarily increase the discrepancy time parameter (e.g., P_DISC_TIME_G4) in the safety controller to rule out rapid asynchronous switching as the cause.