Applicable Systems
EFC
FEX
FEI
HNC
Symptoms
Safe terminal position exceeded. The safety system has detected that the motor position has exceeded the configured safe end-of-travel limit. The safe stop function is activated.
Possible Causes
- Motor moved beyond the safe positive or negative position limit
- Position feedback (encoder) error causing false position reading
- Safe position limits set incorrectly for the application
- Mechanical end-stop failure allowing overtravel
Troubleshooting Steps
- Step 1: Check the safe position limit parameters in IndraWorks AS
Limits match the mechanical travel range from the safety assessment - Step 2: Verify position feedback accuracy by comparing with mechanical reference
Position reading matches actual mechanical position - Step 3: Inspect mechanical end-stops and limit switches for proper operation
End-stops function correctly; limit switches trigger at correct positions - Step 4: If the motor genuinely overtraveled, investigate the controller and mechanical system
Address controller tuning or mechanical brake issues
How to Reset
1) Investigate position feedback. 2) Verify safe position limits. 3) Check mechanical end-stops. 4) Reset requires safety acknowledgment. Caution: Safe position parameters are safety-critical and must only be modified after a proper safety assessment.
Frequently Asked Questions
- Q: How do safe terminal positions differ from regular travel limits?
Safe terminal positions are safety-certified limits enforced by the safety system, independent of the standard controller. They trigger a safety-rated stop (STO or SS1). Regular travel limits are controller-level software limits only.
- Q: What happens when the safe position limit is exceeded?
The safety system immediately activates a safe stop function (typically Safe Torque Off or Safe Stop 1), removing torque from the motor to prevent overtravel beyond mechanical end-stops.
Source: Rexroth IndraDrive Safety Integrated Manual, Bosch Rexroth AG
Category: PLC & VFD