Code 12650: Channel %1 block %2 axis identifier %3 different in channel %4
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical Channel %1 block %2 axis identifier %3 different in channel %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 = Block number %3 = Source symbol %4 = Channel number with different axis definition Definitions: In cycles that are preprocessed at Power On, onl y those geometry and channel axis identifiers may be used that exist in all channels with the same meani ng. In different channels, different axis indices are assigned to the axis identifier. The axis identifiers are defined via MD 20060 $MC_AXCONF_GEOAX_NAME_TAB and MD20080 $MC_AXCONF_CHANAX_NAME_TAB. Example: C is the 4th channel axis in channel 1 and the 5th channel axis in channel 2. If the axis identifier C is used in a cycle that is preprocessed at Po wer On, then this alarm is issued. Reaction: Interpreter stop NC Start disable in this channel. Interface signals are set. Alarm display. Remedy: Please inform the authorized personnel/service department. 1. Modify machine data: Select the same identifi ers for geometry and channel axes in all channels. Example: The geometry axes are called X, Y, Z in all channels. They can then also be programmed directly in preprocessed channels. 2. Do not program the axis directly in the cycle but define it as a parameter of the axis type. Example: Cycle definition: PROC DRILL(AXIS DRILLAXIS) G1 AX[DRILLAXIS]=10 F1000 M17 Call from the main program: DRILL(Z) 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 12650 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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