Code 75608: [Channel %1: ] RESU: NC memory limit reached, RAM type %2
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] RESU: NC memory limit reached, RAM type %2 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
Definitions: A memory limit was reached on writing to file cc_res u.mpf. The possible area for return traveling is shortened. RAM type = 1: File cc_resu.mpf is created in the buffer memory (SRAM). The buffer memory is therefore full. If the buffer memory is used and if alar m 75608 with RAM type 1 is output, system alarm 6500 will be output simultaneously. RAM type = 2: The memory limit was reached on creating file cc_resu.mpf in the dynamic memory (DRAM part program memory). Reaction: Alarm display. Remedy: RAM type = 1: Increase size of buffer memory ($MN_MM_USER_MEM_BUFFERED) or the available space in the buffer memory, e.g. by unloading unused parts programs. Alternatively the ring buffer can be decreased via MD $MC_RESU_RING_BUFFER_SIZE. Program Continuation: Clear alarm with the Delete key or NC START.
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 75608 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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