LogrobotLM

LogrobotLM — AI fault diagnosis for ABB · KUKA · FANUC robots. It reads your robot backup in your browser (never uploaded) and pinpoints the fault. Try it free →

ABB Error 38101 — SMB communication failure

Error

ABB 38101 (“SMB communication failure”): The serial link between the controller and the Serial Measurement Board (SMB) failed. Likely part: Liaison SMB d'axes (link SMB axis).

Updated 2026-09-17 · LogrobotLM reference

What it means

The serial link between the controller and the Serial Measurement Board (SMB) failed. The controller loses axis position feedback — motion stops. Other interventions show it intermittently on one axis first (worn measurement cable), often with 37108, sometimes followed by revolution-counter losses (20032).

What to check

  • Inspect the measurement cable end-to-end — especially flexing segments near the faulted axis.
  • Reseat/inspect SMB connectors (oxidation, bent pins, tightness).
  • Check the SMB battery state; a dying battery adds counter losses (20032).
  • If the fault follows one axis under motion, swap-test the cable segment before the SMB itself.

Part to check / replace

ABB 38101 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

37108Communication lost with unit20032Revolution counter not updated50296SMB memory / data mismatch

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 →