Applicable Systems
PLC
Symptoms
The PLC reports a limit switch activation. A travel limit switch was triggered, stopping motion to prevent mechanical overrun.
Possible Causes
- Axis reached the physical travel limit and activated the limit switch
- Limit switch wiring fault causing false trigger
- Positioning error causing the axis to travel beyond the expected range
Troubleshooting Steps
- Step 1: Check the limit switch activation and verify the axis position
Limit switch was correctly triggered at the travel end - Step 2: Verify the limit switch wiring and function in the drive system
Limit switch operates correctly - Step 3: Clear the limit switch and jog the axis back to the valid travel range
Axis is back within the valid travel zone
How to Reset
To reset: Clear the limit switch and move the axis to valid range, then restart.
Source: B&R Automation System Manual, B&R Industrial Automation
Category: PLC & VFD