Siemens alarm F31103: Encoder 1: Amplitude error track R
SINAMICS S120 encoder fault (Sensor Module / DRIVE-CLiQ encoder) · SINAMICS S120
What it means
The amplitude of the reference-track signal (RP/RN) left its tolerance window - either the unipolar level exceeded roughly 3.5 V or the differential amplitude fell below about 1.6 V. Since homing and absolute-position checks rely on track R, the drive stops trusting the encoder. The hex fault value carries the instantaneous R-track level for diagnosis.
Likely causes
- aged LED or soiled coding disk in the encoder
- encoder speed range beyond the measuring equipment's frequency response
- shielding/grounding deficiencies on the encoder cable
- RP/RN conductors miswired or intermittent plug contact
- defective encoder or encoder cable
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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6FX2001-… encoder cable
cable · Common cause
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6SL3362-0AG00-0AA1 SME20 Sensor Module (if evaluation stage suspect)
sensor-module · Common cause
Need the part urgently?
Send us alarm F31103 with your machine details — typical RFQ turnaround is 24–48h.