M62 can be used to command bar pusher to load new bar, then wait for PLC input X7 to be active.
The ladder program in the standard PLC Expanded I/O option includes M-Funtions for setting live tools ON or OFF, and for controlling some automatic bar feeders.
If you want to connect an automatic bar-loader to your G4 OmniTurn, a less expensive kit is available.
If you need a small, fast, inexpensive automatic bar-loader, consider the OmniTurn ZipLoader.