FANUC Alarm SRVO-071 — SERVO SPHAL alarm
Error- Hardware
- Pulsecoder (encoder)
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SERVO2
- Hardware family
- FANUC Pulsecoder, backup battery and position loss alarms
Manufacturer wording — SERVO SPHAL alarm (Grp:%d Ax:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-071 (“SERVO SPHAL alarm”): The feedback speed is abnormally high (3750 rpm or greater). First check: 1. This alarm does not indicate the main of the problem issued together with the PHAL alarm (SRVO-064). Likely part: Pulsecoder (Pulsecoder (motor encoder)).
Updated 2026-10-22 · LogrobotLM reference
Description
The feedback speed is abnormally high (3750 rpm or greater).
Remedy
1. This alarm does not indicate the main of the problem issued together with the PHAL alarm (SRVO-064). 2. Check whether the load applied to the robot exceeds the maximum rating. If the rated load is exceeded, reduce the applied load. After replacing, master the robot. 3. Replace the pulse coder of the motor.
Field diagnosis
The speed measured by the encoder feedback is implausible: most often a false reading due to noise.
What to check
- With PHAL (SRVO-064) present, SPHAL is not the root cause.
- Improve grounding and shielding, then replace the Pulsecoder (mastering to be redone), the amplifier, the robot connection cable, the internal cable.
- Note: Typical after a robot connection cable has been extended without restoring the shield.
Part to check / replace
FANUC SRVO-071 points to the hardware below — start here before ordering.
Tap a part for every code that points to it — and verify the exact variant for your controller before ordering.
Related codes
Same hardware involved
Indicative field information — the robot manufacturer's manual and safety procedures always prevail. Never bypass a safety device; apply lockout/tagout (LOTO) before any physical intervention. How this reference is built →