The possible causes are:

1. When defining the function "Modification of canned cycle parameters (G79)", the parameter to be modified has not been indicated.
2. While editing the machine parameter table, the wrong parameter number has been entered (maybe the "P" character is missing) or another action is beingcarried out (moving around in the table) before quitting the table editing mode.

The solution for each cause is:

1. To define the "G79" function, the cycle parameter to be modified must be indicated as well as its new value.
2. Enter the parameter number to be edited or press [ESC] to quit this mode.