Setting up external E-stop, limits & home switches

andypugh wrote:

AggieMEEN wrote:

Personal note: am not sure why a NC E-Stop switch would need an invert at this time, and that is unacceptable. Clearly I have a lot to learn.

How is the e-stop switch wired?

The parallel port pins have a pull-up, so if they are not connected to ground they float high (value 1 in HAL)
One way to wire is to connect the E-stop to ground and the pin. Any fault in the wire, or if the button is pressed, allows the pin to float high, and trigger the fault.

It sounds like your switch is connected to +5V, so I rather suspect that pressing it will not result in a state-change of the parallel port pin.

The E-stop is wired from Pin10 to ground (or pin 12, which is also wired to ground) on the G540 terminal block. Pressing it breaks the connection to ground. From what you describe it sounds like an E-stop trigger makes the pin float high, which would mean I'd want to set E-Stop In to inverted in stepconf wizard. Do I have the concept right?

I didn't know about the parallel ports going high if a connection is open! (Another tidbit to add to my Clue Bag.)

So if my limit and home switches are NC, I'd want to have those input signals set to invert in stepconf, yes?

@CNCbasher: I should have been clearer. I say it's unacceptable because, while I was able to achieve what I set out to do, I didn't fully understand why things are working now. It feels like I got lucky this time.

Still. I've got my E-Stop working, and I'm a little further along in the learning curve. Gotta start somewhere!