Code 201706: <location>SI Motion CU: Safe Acceleration Monitor limit exceeded
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>SI Motion CU: Safe Acceleration Monitor limit 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: After initiating STOP B or STOP C, the velocity has exceeded the selected tolerance. The drive is shut down by the message C01700 "SI Motion: STOP A initiated". Remedy: Check the braking behavior, if required, adapt the tolerance for "Safe Acceleration Monitor". 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 SINU MERIK: Via the machine control panel. Note: SBR: Safe Acceleration Monitor SI: Safety Integrated See also: p9548 (SI Motion SBR actual velocity 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 201706 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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