Are you sure it is the chuck causing the problem? If I want to run more than one cycle at a time like when using a puller and bar feed compared to running single part slugs I have to use a different M-code at the end of the program. Also if the % character is missing at the end the program it won't rewind to the top unless you hit reset.
Hello Dualkit,
Its not possible for a program to exist with the % character missing at its end, in the memory of a Fanuc Control. You will note that there is no % character available via the keypad. Accordingly, its not possible to either input, or fail to input this character when creating a program via Finger Cam. When a new program is started by keying "O", a program number and Insert, the % character automatically appears immediately after the Program Number and will continue to appear after all subsequent Inserts of code.
Similar to not being able to Input (Insert) a % character, nor can this character be deleted from the program. Accordingly, there is no scope to inadvertently delete it.
If a program not containing a % character at its end, is Uploaded to the Control from an external device, the transfer will progress without an issue until the end of the file is reached by the External Device, at which point the Control simply waits with the LSK blinking. If you now press Reset at the Control, the program that has been sent to it appears, complete with the % character at its end. Accordingly, its not possible to transfer a program without a % character at its end to Fanuc Control and result in the program in the Control's memory being without the % character at its end.
Depending on how the Comms Software handles the omission of the % character, it will either hang, or simply do what it normally does at the end of a file. In my own software, I look for the % character as the EOF. Therefore, my software simply waits for Esc to be pressed to abort.
Irrespective of whether there is a % character, or not, this character has Zero to do with the program returning to the Start of the Program. This is the function of M02 (M30). These M Codes stops Automatic Operation and the CNC unit is reset. This differs with the machine tool builder. For FS16 Control onward, Bit 5 of Parameter 3404 (M02) or Bit 4 of Parameter 3404 (M30) can be used to disable M02, M30 from returning control to the start of the program.
Regards,
Bill