Code 201707: <location>SI Motion CU: Tolerance for safe operating stop exceeded
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>SI Motion CU: Tolerance for safe operating stop exceeded alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Message value: Drive object: SERVO, VECTOR Reaction: NONE Acknowledge: IMMEDIATELY (POWER ON) Cause: The actual position has distanced itself further from the target position than the standstill tolerance. The drive is shut down by the message C01701 "SI Motion: STOP B initiated". SINAMICS-Alarms Remedy: - check whether safety faults are present and if required carry out the appropriate diagnostic routines for the particular faults. - check whether the standstill tolerance matches the accuracy and control dynamic performance of the axis. - carry out a POWER ON. This message can only be acknowl edged as follows in the acceptance test mode without POWER ON: - motion monitoring functions integrated in the driv e: Via Terminal Module 54F (TM54F) or PROFIsafe - motion monitoring functions with SI NUMERIK: Via the machine control panel Note: SI: Safety Integrated SOS: Safe Operating Stop / SBH: Safe operating stop See also: p9530 (SI Motion standstill tolerance (Control Unit))
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 201707 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
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