75601

Review the NC block listed in alarm message (block %2) in the source program file. Locate the CC_PREPRE() call and examine the parameter value being passed.

Verify the parameter is one of the three valid values: _1 (corner compensation off), 0 (corner compensation inactive), or 1 (corner compensation active). Check for variable assignments or expressions that may evaluate to invalid integers like 2, -2, or floating-point values.

Correct the CC_PREPRE() parameter to a valid value and reload the program via the NCK editor or HMI interface (typically Operate > Program > Load).

Perform a dry-run or block-by-block cycle start to verify the corrected block executes without alarm 75601 recurrence.

Inspect variable declarations in the subroutine or main program where CC_PREPRE() is called. Confirm the variable is declared as INT data type and initialized before use.

Trace the variable's value assignments in preceding NC blocks using breakpoints or diagnostic output (e.g., SETAL, SETAF for diagnostic display on HMI).

Ensure variable assignment logic limits the value to {_1, 0, 1} via conditional statements or parameter validation before the CC_PREPRE() call.

Test the corrected program with manual data input or simulation mode to confirm variable initialization and range validation.

Cross-reference the NC block against official Siemens SINUMERIK 840D programming documentation (SINUMERIK 840D/840DE NC Programming Guide, Part 1 & 2) to confirm correct function name and parameter syntax.

Verify no typos exist in the function call (e.g., CC_PREPRE vs. CC_STOPRE; confirm the correct function for the intended corner compensation mode).

Replace the function call with the correct SINUMERIK 840D corner compensation syntax and re-save the program.

Recompile and load the program; cycle-start to confirm alarm 75601 is resolved.