Siemens alarm 25201: Axis %1 drive %2 fault (ZK1 class 1 serious drive fault)
SINUMERIK 840D sl / 828D drive umbrella alarm (PROFIdrive) · Siemens 828D
What it means
Drive signalled serious status-class fault; root cause must be read from accompanying drive alarms (300500/300502-300505/300508/300515/300614 on PL) or SINAMICS F-codes / 380500 fault value (on sl/828D). Persistent after 25202 'waiting for drive' times out.
Likely causes
- any underlying SINAMICS/611D hardware fault (overcurrent, I2t, encoder, DRIVE-CLiQ)
- PROFIBUS/PROFINET drive communication interruption (loose connector, shield break)
- cycle-time overrun on drive bus
- drive electronics supply collapse
Triage note: On 840D sl/828D open Diagnosis > Alarms > drive fault buffer (r0947/r0949 equivalent) to get the exact SINAMICS fault before ordering parts.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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per underlying fault code
read subordinate drive alarm / 380500 fault value first · Primary suspect
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6XV1830-… / 6SL3066-0BA00-…
PROFIBUS / DRIVE-CLiQ cable · Common cause
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NCU 71x.x (6FC5373-…) or PPU (6FC5370-…)
NCU/CCU or PPU (only if bus master port failed) · Check if others ruled out
Need the part urgently?
Send us alarm 25201 with your machine details — typical RFQ turnaround is 24–48h.