Code 201200: <location>CU: Time slice management internal software error
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>CU: Time slice management internal software error 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: All objects Reaction: OFF2 Acknowledge: IMMEDIATELY (POWER ON) Cause: A time slice management error has occurred. It is possible that the sampli ng times have been inadmissibly set. Fault value (r0949, interpret hexadecimal): 998: Too many time slices occupied by OA (e.g. DCC) 999: Too many time slices o ccupied by the basic system Too many different sampling times may have been set. Further values for inter nal Siemens troubleshooting. Remedy: - check the sampling time setting (p0112, p0115, p4099). - contact the Hotline. 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 201200 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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