Code 16671: [Channel %1: ] Block %2 following axis/spindle %3 maximum number of CP modules (%4) has been exceeded
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 following axis/spindle %3 maximum number of CP modules (%4) has been exceeded 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 = Axis name, spindle number %4 = Max. number of CP modules Definitions: An attempt was made to activate more generic couplings than are configured in MD18450 $MN_MM_NUM_CP_MODULES. Reaction: NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm. Remedy: Reduce the number of defined or active couplings, or increase the number of coupling modules configured in MD18450 $MN_MM_NUM_CP_MODULES. If necessary, buy another option stage of the generic coupling. Program Continuation: Clear alarm with the RESET key in all channels. Restart part 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 16671 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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