Code 10950: [Channel %1: ] Calculation of arc length function too inaccurate
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Calculation of arc length function too inaccurate 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
Parameters: %1 = Channel number Definitions: The calculation of the arc length function coul d not be performed to the required accuracy. Reaction: Alarm display. Warning display. Remedy: The calculation of the arc length function could not be performed to the required accuracy during active polynomial interpolation. Either in crease MD20262 $MC_SPLINE_FEED_PRECISION or reserve more memory for the representation of the arc length polynomials. MD28540 $MC_MM_ARCLENGTH_SEGMENTS defines how m any polynomial segments can be used per block in order to approximate the arc length function. Program Continuation: Clear alarm with NC ST ART or RESET key and continue the program.
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 10950 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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