Code 16747: [Channel %1: ] Block %2 spindle %3 inserted gear stage %4 for tapping not installed
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 spindle %3 inserted gear stage %4 for tapping not installed 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 = Spindle number %4 = Gear stage Definitions: The second gear stage data block has been activated for tapping with G331. However, the current gear stage has not been installed in the second gear stage data block. The number of gear stages installed is configur ed in MD35092 $MA_NUM_GEAR_STEPS2. The gear stage cannot be changed in traversing blocks. The gear stage appropriate for the speed must be loaded before the traversing block. Reaction: Correction block is reorganized. Interface signals are set. Alarm display. Remedy: Procedure for automatically engaging the suitable gear stage prior to thread cutting: * Program the spindle speed (S) in a G331 block wit hout axis motions and prior to thread cutting, e.g. G331 S1000. * Activate M40 for the spindle. 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 16747 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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