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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 840D 310708 - Axis drive number of encoder marks of measuring system invalid
Siemens SINAMICS drive alarm 310708: Axis drive number of encoder marks of measuring system invalid. The encoder or position measuring system connected to the SINAMICS drive has reported a fault. This prevents reliable position feedback for the affected axis.
310708
Siemens 840D 310708 - Axis drive number of encoder marks of measuring system invalid
Axis drive number of encoder marks of measuring system invalid
Siemens SINAMICS drive alarm 310708: Axis drive number of encoder marks of measuring system invalid. The encoder or position measuring system connected to the SINAMICS drive has reported a fault. This prevents reliable position feedback for the affected axis.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Common Causes
- Encoder cable damaged or connector loose at drive or encoder end
- Encoder signal amplitude below minimum specification — contamination or cable issue
- SSI or EnDat measuring system communication fault
- Encoder supply voltage out of specification
- Measuring system hardware failure
Troubleshooting Steps
- 1Check encoder/measuring system cable for damage and reseat connectors.
- 2Clean the measuring system reading head and scale if contamination is present.
- 3Verify encoder supply voltage at the connector.
- 4Check SINAMICS drive diagnostics for detailed fault sub-codes.
- 5Replace encoder cable first; replace sensor head if cable checks out.
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Always verify with your machine manual or a certified technician before performing service procedures.