I’m happy to help.
Are you referring to identify if the part needs to be refected or to the electrical signal needed to perform the actual reject?
In most applications I’ve worked with, I used the PLC for the reject as I’d also count them / report them there. Therefore, I typically would send the reject over EtherNet/IP which is covered in the course. There’s a hard wired signal for pass / fail on the Cognex camera. I’ve seen it used as well, but you have less flexibility with that signal if you directly drive a relay with it. I’d still send that to a PLC input and process the signal from there.
Let me know where you’re stuck and I’ll do my best to help / potentially cover it in a video.