Code 18000: [Channel %1: ] Block %2 NCK-specific protection zone %3 wrong. Error code %4
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 NCK-specific protection zone %3 wrong. Error code %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, label %3 = Number of NCK protection zone %4 = Error specification Definitions: There is an error in the definition of the protecti on zone. The error number gives the specific reason for the alarm: No.Meaning 1: Incomplete or conflicting contour definition. 2: Contour encompasses more than one surface area. 3: Tool-related protection zone is not convex. 4: If both boundaries are active in the 3rd dimens ion of the protection zone and both limits have the same value. 5: The number of the protection zone does not exist (negative number, zero or greater than the maximum number of protection zones). 6: Protection zone definition consists of more than 10 contour elements. 7: Tool-related protection zone is defined as insi de protection zone. 8: Incorrect parameter used. 9: Protection zone to be activated is not defined. 10: Incorrect modal G code used for protection zone definition. 11: Contour definition incorrect or frame activated. 12: Other, not further specified errors. Reaction: Correction block is reorganized. Interface signals are set. Alarm display. Remedy: Please inform the authorized personnel/service departmen t. Modify definition of the protection zone and check MD. 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 18000 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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