FANUC Alarm SRVO-221 — Lack of DSP
Error- Hardware
- FSSB link and axis control card
- Controllers
- R-J3iB / R-30iA / R-30iB
- FANUC class
- SERVO
Manufacturer wording — Lack of DSP (G:%d A:%d)
The manual prints placeholders; your controller fills them in with the real group, axis or number.
FANUC SRVO-221 (“Lack of DSP”): The DSP (servo control CPU) for this axis was not found, though it was specified in the system variable $AXISORDER. First check: 1. Check that the number of DSPs on the board for DSP is sufficient for the quantity specified in $SCR_GRP[].$AXISORDER[].
Updated 2026-10-22 · LogrobotLM reference
Description
The DSP (servo control CPU) for this axis was not found, though it was specified in the system variable $AXISORDER.
Remedy
1. Check that the number of DSPs on the board for DSP is sufficient for the quantity specified in $SCR_GRP[].$AXISORDER[]. 2. Replace the board for the DSP with one having sufficient DSPs if necessary. 3. Alternatively, change the setting of $AXISORDER.
Field diagnosis
The servo processor intended for this axis does not exist: the fitted axis control board does not carry enough DSPs for the configured number of axes.
What to check
- Check the configured number of axes (axis order); if the configuration is correct, fit an axis control board with sufficient capacity, otherwise correct the configuration.
- Note: Appears after adding an auxiliary axis without changing the board.
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 →