Code 201700: <location>SI Motion CU: STOP A initiated
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>SI Motion CU: STOP A initiated 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: OFF2 Acknowledge: IMMEDIATELY (POWER ON) Cause: The drive is stopped via a STOP A (pulses are suppres sed via the safety shutdown path of the Control Unit). Possible causes: - stop request from the higher-level control. - pulses not suppressed after a parameterized time (p9557) after test stop selection. - subsequent response to the message C01706 "SI Motion CU: Safe Acceleration Monitoring limit exceeded". - subsequent response to the message C01714 "SI Motion CU: Safely-Limited Speed exceeded". - subsequent response to the message C01701 "SI Motion CU: STOP B initiated". SINAMICS-Alarms Diagnostics Manual (DAsl), 03/2009 Remedy: - remove the fault cause in the control and carry out a POWER ON. - check the value in p9557, if necessary, increase the value, and carry out POWER ON. - check the shutdown path of the Control Unit (check DRIVE-CLiQ communication). - carry out a diagnostics routine for message C01706. - carry out a diagnostics routine for message C01714. - carry out a diagnostics routine for message C01701. - replace Motor Module. - replace Control Unit. 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: SI: Safety Integrated
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 201700 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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