Code 18204: [Channel %1: ] Block %2 curve table: instruction SUPA not within CTABDEF
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 curve table: instruction SUPA not within CTABDEF 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, label Definitions: G code SUPA is not allowed for the definition of a cu rve table, as it triggers a preprocessing stop. Reaction: Interpreter stop NC Start disable in this channel. Interface signals are set. Alarm display. Remedy: Remove G code SUPA from the curve table definiti on. If possible, use G c odes G53 or G153 instead of SUPA. Program Continuation: Clear alarm with the RESET key. Restart part program Diagnostics Manual (DAsl), 03/2009
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 18204 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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