Code 27050: Axis %1 SI communication failure.
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical Axis %1 SI communication failure. 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 = Axis number Definitions: Communication with the drive for Safety Integrat ed motion monitoring is additionally monitored. This monitoring has found an error. Reaction: NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm. In addition, a STOP F is triggered that may cause follow-up alarm 27001 with er ror code 0 as well as alarms 27023 and 27024. Alarm 27001 with error code 0 can be avoided by alarm reduction($MN_SAFE_ALARM_SUPPRESS_LEVEL higher or equal to 1). Remedy: Check the connections between NCK and drive. Check the configuration of the PROFIBUS telegram (e.g. SI slot configured). Check the assignment of the NCK SI axis to the SI slot ($MA_SAFE_CTRLOUT_MODULE_NR, $MN_SAFE_DRIVE_LOGIC_ADDRESS). Check for compliance with the EMC requirements. Check the assignment of the telegr am configuration for the slave OM Program Continuation: Clear alarm with the RESET key. Restart part 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 27050 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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