Code 201485: <location>Topology: Comparison CX32 missing in the actual topology
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Topology: Comparison CX32 missing in the actual topology 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: Component number: %1 Drive object: All objects Reaction: NONE Acknowledge: NONE Cause: The topology comparison has detected a controller extension 32 (CX32) in the target topology that is not available in the actual topology. Alarm value (r2124, interpret decimal): Component number of the additional target components. SINAMICS-Alarms Diagnostics Manual (DAsl), 03/2009 Remedy: - delete the CX32 / NX in the commissioning softwar e project and download the new configuration to the drive unit. - check that the actual topology matches the target topology and if required, change over. - check DRIVE-CLiQ cables for interruption and contact problems. - check the 24 V supply voltage. - check that CX32/NX functions correctly. Note: Under "Topology --> Topology view" the commissi oning software offers improved diagnostics capability (e.g. setpoint/actual value comparison).
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 201485 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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