Code 10784: [Channel %1: ] Block %2 illegal tool for tool radius compensation with constraint surface
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 illegal tool for tool radius compensation with constraint surface 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: When activating the tool radius com pensation with constraint surface, an illegal t ool type is active. Only cutting tools of the tool types 1 to 399 are admitted with the following exceptions: - 111 ball end milling cutter - 155 torus milling cutter - 156 torus milling cutter - 157 torus milling cutter Reaction: Correction block is reorganized. Local alarm reaction. Interface signals are set. Alarm display. NC Stop on alarm at block end. Remedy: Use another tool. Program Continuation: Clear alarm with NC ST ART or RESET key and continue the 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 10784 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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