Code 207971: <location>Drive: Angular commutation offset determination activated
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Drive: Angular commutation offset determination activated 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: NONE Cause: The automatic determination of the angular commuta tion offset (encoder adjus tment) is activated (p1990 = 1). The automatic determination is carried out with the next power-on command. For SERVO and fault F07414 present, the following applies: The determination of the angular commutation offset is automatically activated (p1990 = 1), if a pole position identification technique is set in p1980. See also: p1990 (Encoder adjustment, determine angular commutation offset) Remedy: None necessary. The alarm automatically disappears after determination or for the setting p1990 = 0. SINAMICS-Alarms Diagnostics Manual (DAsl), 03/2009
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 207971 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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