Error "negative limit switch".

What does 151 mean?

The negative limit switch has been reached, preventing further movement of the drive in the negative direction. This is a safety mechanism to prevent overtravel.

• Physical actuation of the negative limit switch by the mechanical system (e.g., gantry, carriage) reaching its physical travel end.
• Negative limit switch (e.g., proximity, mechanical, optical) is damaged, misaligned, or stuck in the actuated position.
• Wiring fault (e.g., short to ground, open circuit) on the negative limit switch input (e.g., Digital Input 1) to the drive controller.
• Incorrect drive parameterization for the limit switch logic (e.g., normally open vs. normally closed, Parameter C0101 for DI1 polarity).
• False trigger due to electrical noise or transient voltages on the limit switch signal line.

Click steps to track your progress.

1. 1

   1. Manually move the mechanical system away from the negative limit switch to disengage it and clear the fault.

2. 2

   2. Monitor the state of the negative limit switch digital input (e.g., DI1) in the drive's diagnostic menu (e.g., Monitoring P5-01) while manually actuating the switch.

3. 3

   3. Use a multimeter to verify electrical continuity of the negative limit switch wiring from the switch terminals to the drive's input terminals (e.g., X1:1).

4. 4

   4. Check the configuration of the negative limit switch input (e.g., Parameter C0101 for DI1 function, C0102 for polarity) to ensure it matches the physical switch type.

5. 5

   5. Inspect the limit switch for mechanical damage, debris, or misalignment that could cause it to stick in the actuated position.