Siemens alarm 300508: Axis %1 drive %2 zero mark monitoring of motor measuring system
SINUMERIK 840D/810D powerline drive alarm (SIMODRIVE 611D) · SIMODRIVE 611D/611U
What it means
Error in number of encoder lines counted modulo on crossing of the zero marker - increments were lost or added.
Likely causes
- failing encoder producing marginal signals
- encoder cable shielding damaged / EMC coupling from power lines
- loose encoder coupling or mechanical slip
- noisy/intermittent connector pins
Triage note: Often accompanies alarm 21612/25201; route encoder cables separated from motor power cables.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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motor encoder (per motor model)
encoder · Common cause
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6FX5002-2E…
encoder cable · Common cause
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6SN1118-…
SIMODRIVE 611D control board · Check if others ruled out
Need the part urgently?
Send us alarm 300508 with your machine details — typical RFQ turnaround is 24–48h.