101601

Identify the NC block number where the alarm occurred by checking the alarm display details and noting the exact line in the part program.

Examine the NC block for R-parameter assignments or reads (e.g., R1500=10 when only R0-R999 are available) and verify the parameter number is within the valid range defined in your system's machine data.

Check if indirect parameter addressing is used (e.g., R[R10]) and verify that the value stored in the indirect parameter produces a valid parameter number within range.

Correct the parameter number to fall within the valid range and reset the alarm. For extended R-parameter ranges, verify MD18118 $MN_MM_NUM_USER_DATA_VARI is configured correctly.

Review the alarm context to determine if machine data or setting data access was being performed (often during startup, tool management, or parameter modification operations).

Identify the specific machine data number being accessed and verify it exists in your SINUMERIK 840D system documentation for your specific software version (e.g., SW 6.3, 6.4, 6.5).

Check if the parameter number includes proper addressing format (e.g., $MN_, $MA_, $MC_ prefixes) and verify channel/axis indices are within configured limits.

Accessing non-existent machine data can indicate software version mismatch or corrupted system files.

Correct the machine data number to match your system configuration or remove the access if the parameter is not applicable to your software version.

Check if the alarm occurs during access to GUD variables defined in _N_DEF_DIR or frame parameters ($P_FRAME, $P_TOOLFRAME, etc.).

Verify the array index used in the program does not exceed the defined array dimensions in the GUD definition file (e.g., accessing MyArray[50] when only MyArray[0..20] is defined).

For frame parameters, confirm that the frame number being accessed (e.g., $P_IFRAME[n]) is within the configured range defined in MD28020 $MC_MM_NUM_GLOBAL_FRAME_SYSTEMS.

Correct the index value or expand the GUD array definition if additional elements are required, then recompile the GUD file and perform a power-on reset.

Changes to GUD definitions require NCK reset and may affect existing programs using these variables.