FANUC 0i-F PS0090: Reference return incomplete after power-up, what to check?
I'm getting a PS0090 (REFERENCE RETURN INCOMPLETE) fault on my FANUC 0i-F after power-up when I try to do a manual reference return. It seems to happen consistently. What should I check first?
The PS0090 fault on a FANUC 0i-F indicates that the reference position return could not be completed normally. This can occur if the return started too close to the reference position, the return speed was too slow, or if there was an issue setting the zero point of an absolute position detector. It typically appears during manual reference return after power-up or when setting the reference position on an absolute-encoder axis.
Likely causes and checks
1Start point too close to the reference position
- Points to it
- The reference position return cannot be performed normally if the start point is too close to the reference position. FANUC recommends at least 2 motor revolutions between the start and the zero point.
- Check
- Jog the axis well away from the reference position and repeat the reference return. Ensure there's enough distance for the return to complete normally.
2Reference return speed too slow
- Points to it
- The reference position return cannot be performed normally if the speed is too slow. This could be due to a low feedrate override or recently changed return feedrates.
- Check
- Check the feedrate override setting. Also, verify the return feedrates (parameters 1428 and 1425) against the machine builder's backup documentation.
3Absolute detector zero point cannot be set yet
- Points to it
- An attempt was made to set the zero point for an absolute position detector when it was impossible to set the zero point.
- Check
- Rotate the motor manually at least one turn. Then, turn the CNC and servo amplifier off and on again, and attempt to set the zero position of the absolute position detector.
4Deceleration dog or switch problem (for dog-type return)
- Points to it
- If the axis uses a deceleration dog for reference return, a problem with the dog or its associated switch can prevent the return from completing normally, either by not slowing down or by repeating the alarm.
- Check
- Check the deceleration dog and the switch signal using the machine builder’s ladder/I/O diagnostics to ensure they are functioning correctly.
Next check: Based on the common causes, first, jog the axis a significant distance away from the reference position and try the reference return again. If the fault persists, check the feedrate override and the reference return speed parameters.
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