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Navigate to Siemens HMI > Diagnosis > Parameter > Machine Data (MD) and locate MD10200 for the faulted axis. Verify the value matches linear SSI specification (consult machine builder documentation for correct type designation).

Do not modify parameters while axis is in motion or under active control.

Cross-reference the encoder hardware specifications against the configured type. Linear SSI encoders output only single-turn absolute position; multiturn types expect revolution counters.

Correct MD10200 to the appropriate linear SSI type and save to non-volatile memory via Parameter > Save/Backup. Power-cycle the control to force NCK re-initialization.

In HMI Parameter view, inspect MD10202 and MD10204-MD10206 (multiturn-related parameters). For linear SSI axes, these should be zero or undefined per SINUMERIK 840D documentation section on linear encoders.

Multiturn parameters must be explicitly cleared (set to 0) for linear measuring systems.

Verify MD10201 contains only linear pitch data (encoder resolution in machine units per count), not revolution-count multipliers.

Clear offending multiturn MDs and re-initialize axis via NCK > Axis > Reset or full control cold-start. Monitor system log for confirmation.

Check the drive module part number and firmware version in Siemens HMI > Diagnosis > Module Information. Confirm the encoder interface board supports linear SSI mode (consult Siemens product datasheet).

Verify the physical encoder connector is the correct linear SSI type (pin configuration and signal specification per IEC 61076-2-109). Multiturn encoders have additional signal lines for turn counting.

Do not hot-swap encoder modules; power down the control completely.

If firmware is outdated, update via Siemens SINUMERIK drive firmware tool (HMI > Service > Firmware Update) to a version explicitly supporting linear SSI on this axis class, then recycle power.