Travel limit stops a direction too early
The drive stops short in one direction — a travel limit is operating before the load reaches the proper end position, cutting the movement off early.
Safety first
Travel limits protect against overtravel and crushing. Don't adjust or bypass a limit to gain travel until you're sure it's safe and correct. Keep clear of the moving load.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Apprentice mode
Full walk-through — the why, what readings mean, mistakes & safety.
Likely causes
Ranked from most to least likely.
- 1
Limit switch out of position / drifted
Most likelyThe limit or its actuator/cam has shifted, so it operates before the true end of travel.
- 2
Bent actuator or worn cam
#2A bent lever or worn cam triggers the switch earlier than intended.
- 3
Wrong limit operating (slowdown vs stop)
#3A slowdown or intermediate limit is being read as the stop limit.
- 4
Intermittent limit contact
Least likelyA flaky limit contact false-triggers early.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
On the tools? Job Mode shows one test at a time with thumb-sized buttons — your place and readings carry straight over.
Enter Job ModeRun toward the limit and watch exactly where/when it operates relative to the intended stop.
Limit operates at the correct end position.
It stops in the right place — the early stop is elsewhere.
It operates early — check the switch position and actuator.
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
Stops too early one direction
→ step 2 - 2decision
Does the limit operate at the correct end position?
Yes→ step 3No→ step 4 - 3result
Limit is fine — the early stop is from another cause.
- 4decision
Is the limit correctly positioned, undamaged, and the right (stop) limit?
Yes→ step 5No→ step 6 - 5decision
Does the contact switch cleanly by hand?
Yes→ step 7No→ step 8 - 6result
Drifted/bent/wrong limit — correct it (safely).
- 7result
Re-verify the position setup.
- 8result
Intermittent/false-triggering — replace the limit.
Common mistakes apprentices make
- Moving a limit to gain travel without checking it's safe to do so.
- Confusing a slowdown limit with the stop limit.
- Not spotting a bent actuator triggering early.
- Ignoring an intermittent contact that false-trips.
When to stop & escalate
On hoists, doors, and anything that can overtravel, limit positions are safety-critical — confirm against the machine's safe limits before adjusting. Replace, don't bodge, a faulty limit.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
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Related faults
Limit switch or proximity sensor not being detected
A limit switch or proximity/photo sensor isn't registering — the machine doesn't stop at position, the input never makes, or the sensor LED looks wrong for the target's position.
Motor goes one way but won't go the other (e.g. down but not up)
A reversing drive works in one direction only. One command (say, down) runs fine; the other (up) does nothing, or just hums/trips. Common on hoists, doors, and conveyors.
Limit switch stuck made (won't release)
A mechanical limit switch stays operated even after the actuator leaves it — the input stays made, so the machine thinks it's still at that limit.
Learn the theory
How the gear and circuits behind this fault actually work.