Code 26281: [Channel %1: ] Axis %2 risk of collision %3 %4
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Axis %2 risk of collision %3 %4 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 %2 = Axis name, spindle number %3 = 1st protection zone %4 = 2nd protection zone Definitions: The stated axis was stopped due to the risk of collision. The programmed path may have been left because it was not possible to stop in ti me on the path (exceptional situation). Reaction: Local alarm reaction. NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm at block end. Remedy: In JOG mode: Retract axis from danger zone. In automatic mode: Determine reason for the risk of collision and eliminate. Possible reasons: wrong NC program, too large handwheel overrides, axis coupl ings and vice-versa impairing of two channels. Program Continuation: Clear alarm with the RESET key. Restart part program The stated axis was stopped due to the risk of collision. The programmed path may have been left because it was not possible to stop in ti me on the path (exceptional situation).
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 26281 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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