FANUC Alarm SRVO-037 — SERVO IMSTP input
Error- Hardware
- I/O Link and process I/O
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SERVO
- Hardware family
- FANUC I/O Link, process I/O board, fuse and output alarms
Manufacturer wording — SERVO IMSTP input (Group:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-037 (“SERVO IMSTP input”): The *IMSTP signal, which is a peripheral device I/O signal, is applied. First check: Turn on the *IMSTP signal.
Updated 2026-10-22 · LogrobotLM reference
Description
The *IMSTP signal, which is a peripheral device I/O signal, is applied.
Remedy
Turn on the *IMSTP signal.
Field diagnosis
The *IMSTP (immediate stop) input of the peripheral interface has dropped: the PLC or the UOP wiring has cut the signal, or the input is not powered.
What to check
- Set the *IMSTP signal active again on the PLC side; check the UOP assignment (UI[1]) and the 24 V supply of the input.
- Without a PLC, the input must be forced or jumpered depending on the chosen configuration.
- Note: Service observation: IMSTP appeared at the same time as a BZAL, unrelated — a secondary fault on the UOP input, to be dealt with separately.
- Diagnostic sequence “Pulsecoder battery sequence”: Complete sequence after loss of position: BZAL (SRVO-062) at power-up, then 075 "position not established" after the encoder reset, then mastering. New batteries with the power on, Pulsecoder reset (RES_PCA or system variable), power cycle, QUICK MASTER if the reference exists (otherwise full mastering), jog of about ten degrees on each affected axis, RESET.
Related codes
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 →