Process of operating a numerical control with critical-time and non-critical-time processes in a real time system

A method for operating a numerical control system having a real-time system, the real-time system having time-critical computing processes and non-time-critical computing processes, each of the computing processes having at least one program sequence, the method comprising the steps of:

• (a) classifying a program sequence of a non-time-critical computing process as a subordinate computing process to limit a running time of the program sequence, the subordinate computing process being subordinate to the respective non-time-critical computing process and having a running-time limit value associated therewith;
• (b) setting a lock indicator assigned to the subordinate computing process before starting a sequence of program steps;
• (c) after processing the sequence of program steps, canceling the lock indicator assigned to the subordinate computing process;
• (d) after a time period corresponding to the running-time limit value elapses, interrupting the subordinate computing process to process at least another non-time-critical computing process that is pending if the lock indicator assigned to the subordinate computing process is not set;
• (e) after a further time period greater than the running-time limit value elapses, interrupting the subordinate computing process to process another of the non-time-critical computing processes that is pending;
• (f) interrupting the subordinate computing process to process another of the non-time-critical computing processes that is pending if the lock indicator assigned to the subordinate computing process is reset in a time interval between the running-time limit value and the further time period;
• and
• (g) interrupting any non-time-critical computing process if a time-critical computing process is pending.