Code 201600: <location>SI CU: STOP A initiated
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>SI 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: %1 Drive object: SERVO, VECTOR Reaction: OFF2 Acknowledge: IMMEDIATELY (POWER ON) Cause: The drive-based "Safety Integrated" function in the Control Unit (CU) has detected a fault and initiated a STOP A (pulse suppression via the safety shutdown path of the Control Unit). - forced checking procedure of the safety s hutdown path of the Control Unit unsuccessful. - subsequent response to fault F01611 (defect in a monitoring channel). Fault value (r0949, interpret decimal): 0: Stop request from the Motor Module. 1005: Pulses suppressed although STO not sele cted and there is no internal STOP A present. 1010: Pulses enabled although STO is selected or an internal STOP A is present. 1015: Feedback of the safe pulse suppression for Motor Modules connected in parallel are different. 9999: Subsequent response to fault F01611. Remedy: - select Safe Torque Off and de-select again. - replace the Motor Module involved. Re fault value = 9999: - carry out diagnostics for fault F01611. Note: CU: Control Unit MM: Motor Module SI: Safety Integrated STO: Safe Torque Off / SH: Safe standstill SINAMICS-Alarms
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 201600 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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