FANUC Series 0i-F / 0i-F Plus alarm PS0090: REFERENCE RETURN INCOMPLETE
PS0090 (REFERENCE RETURN INCOMPLETE) on a FANUC 0i-F means the reference position return could not be completed normally. FANUC gives two cases: the return started too close to the reference position or ran too slowly, or an attempt was made to set the zero point of an absolute position detector when it could not yet be set.
Diagnose this with AI
Try Free CNC Alarm Diagnostic Upload a keypad photo, the fault history or a parameter export from your FANUC Series 0i-F / 0i-F Plus. InduQT compares the evidence and suggests the next useful checks.
When it happens
- Manual reference return after power-up
- Setting the reference position on an absolute-encoder axis (after DS0300)
Likely causes and checks
1Start point too close to the reference position
- Points to it
- Axis was parked near home before the return; works if moved away first.
- Check
- Jog the axis well away from the reference position and repeat. FANUC’s related DS0405 text asks for at least 2 motor revolutions between the start and the zero point.
2Reference return speed too slow
- Points to it
- Feedrate override low, or return feedrates recently changed.
- Check
- Check the override and the return feedrates (parameters 1428 and 1425) against the builder’s backup.
3Absolute detector zero point cannot be set yet
- Points to it
- Axis uses an absolute Pulsecoder and DS0300 was showing; setting the zero point fails.
- Check
- Follow FANUC’s remedy: rotate the motor at least one turn, switch the CNC and servo amplifier off and on, then set the zero position again.
4Deceleration dog or switch problem (dog-type return)
- Points to it
- Axis does not slow down at the dog, or the alarm repeats from a good start position.
- Check
- Check the deceleration dog and switch signal with the machine builder’s ladder/I/O diagnostics.
Telling it apart
- PS0224 (ZERO RETURN NOT FINISHED) is raised when automatic operation starts before a reference return (with 1005#0 ZRN = 0); PS0090 is the return itself failing.
- DS0405 (ZERO RETURN END NOT ON REF) means positioning finished but not on the zero point, which FANUC links to too short a return distance, low positional deviation after the dog, or Pulsecoder voltage problems.
- DS0309 is the MDI version of the absolute zero-point case.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| 1425 | FL rate of the reference position return | Slow speed after the deceleration dog. |
| 1428 | Reference return feedrate before a reference is established | Return speed before the first reference return. |
| 1005#0 (ZRN) | Alarm on automatic operation without reference return | 0: PS0224 if automatic operation starts without a reference return. |
| 1005#1 (DLZ) | Reference setting without dogs | Enabled on dogless axes. |
Evidence to collect
- Axis and start position of the return
- Override and return feedrates
- Whether the axis has an absolute Pulsecoder and whether DS0300 was active
- Dog switch signal state
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