Numerical control working

There's not all that much to it as long as the CNC control truly allows direct numerical control. For Fanuc models 6MB and more recent, for example, as long as your communications protocol is properly set up (baud rate, stop bits, handshaking, etc.), the actual task of running a the CNC machine from an off line computer is pretty easy.

This is pretty much the same protocol used for distributive numerical control (transferring a program in its entirety), but with an emphasis on handshaking - usually with xon/xoff . Usually a setting parameter controls whether the cycle start button will activate a program in the control's memory or a program from the serial communications port (computer). With Fanuc controls, it's usually on the setting page and labeled Input Device. For most control models, it must be set to RMT (For remote) when you want to run directly from a computer.

After ensuring that the connection is made between the control and computer and parameter settings are correct, most controls simply require that you first turn on single block (so the program won't run until you're ready for it to).

Next, you press the cycle start button. But since there is no program coming through the serial port (yet), and because of handshaking, the control will simply wait.

Finally, you go to the computer and send it to the machine (like you do for distributive numerical control). When you get back to the machine, you'll notice that it has executed the first command of the program (the program number for a Fanuc control) and stopped (since single block is on).

When you turn off single block and press the cycle start button, the control will execute the program.

With most controls, however, you won't see much of the program on the display screen (as you do when executing a program from memory). Only what's in the look ahead buffer will be displayed. And of course, you won't be able to edit the program at the control as you can when executing a program from memory.