Code 15177: [Channel %1: ] Block %2 Error on preprocessing of program %3, error code: %4
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 Error on preprocessing of program %3, 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 = File name %4 = Error code Definitions: If an encrypted program is loaded to the NCK, an NCK reset (restart) must be performed afterwards, because internal data for efficient processing of the encrypted program are preprocessed during NCK power-up. The following problem has occurred: Error code 1: Error on read-in of program %4 Error code 2: There is not enough DRAM memory available for storing the preprocessed data. Reaction: Interpreter stop NC Start disable in this channel. Interface signals are set. Alarm display. Remedy: Error code 1: Encrypt and load program %4 again. Then perform an NCK reset (restart). Error code 2: Increase system SL 710-740, 802D, 828D: $MN_MM_T_FILE_MEM_SIZE. Increase system SL 840 DI: $MN_MM_DRAM_FILE_MEM_SIZE. Then perform an NCK reset (restart). Program Continuation: Clear alarm with the RESET key. 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 15177 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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