Siemens alarm 26030: Axis %1 encoder %2 absolute position lost
SINUMERIK axis/spindle alarm · Siemens 840D/810D powerline
What it means
The absolute encoder's stored absolute position is no longer valid: the value could not be read plausibly at initialization or the permitted multi-turn range was violated. Position control requiring an absolute reference is blocked until the encoder is re-initialized/referenced.
Likely causes
- serial communication error during encoder initialization (cabling, connectors)
- encoder moved while control off beyond the permitted number of turns
- internal encoder memory/electronics fault
- absolute function machine data (MD 34200/34210) inconsistent after encoder swap
Triage note: After eliminating the cause, re-establish the absolute reference (re-referencing or absolute initialization) before production.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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6FX2001 series absolute encoder (EnDat)
encoder · Common cause
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6FX5002 series encoder signal cable
cable · Common cause
Need the part urgently?
Send us alarm 26030 with your machine details — typical RFQ turnaround is 24–48h.