Siemens alarm 26102: Axis %1 drive %2 sign of life missing
SINUMERIK 840D sl drive communication alarm (PROFIdrive) · Siemens 840D/810D powerline
What it means
Sign-of-life cell of the cyclic telegram is no longer updated by the drive - drive froze or stopped telegrams.
Likely causes
- drive module crashed/hung (watchdog)
- PROFINET/PROFIBUS packet loss from cabling or switch
- drive electronics power disturbance
- firmware/topology inconsistency after component swap
Triage note: If recurring on one drive only after cabling checks, suspect that drive's electronics board.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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6SL3120-… (booksize) / 6SL33xx (chassis)
affected SINAMICS motor module · Common cause
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6SL3066-0BA00-…
DRIVE-CLiQ/PROFINET cabling · Common cause
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6FC5373-4… (NCU) firmware image
NCU system software reload (non-hardware fix) · Check if others ruled out
Need the part urgently?
Send us alarm 26102 with your machine details — typical RFQ turnaround is 24–48h.