Proxy question...

[racedirector]

Been going through my wiring plans and now have a question, Can the proxies serve a double purpose. I am proposing they would act as home switches, they also act as limit switches (they would trigger a pause if they trigger on the ends of the machine), and also as protection against lifting of the gantry - again triggering a pause NOT an estop.

First of all, does this make sense and second of all is it doable within the bounds of a PMDX122?

Cheers

[alan254]

Yes I am using a 122 and mech3 and it will stop and home also e stops in case of a lifted carnage.

Al

[bradm]

Yikes. Is your "pause" going to stop the router or spindle, and if so, how? If not, this is a recipe for a fire. The primary cause of a gantry lift is that the bit is in close contact with something it cannot overcome. You don't want it rubbing against that thing any longer than necessary. Similarly, if you hit the limit switches, something has gone very wrong. It both cases, you should estop.

It is true that the proxies can serve as home, limit, and lift sensors. But limits and lift should estop.

If you're thinking about trying to save the workpiece, note that at the very least, you'll need to be rehoming the machine before continuing, and that alone negates any value from a pause.

[pblackburn]

I would not worry about using a single prox for home and limit. If you had more IO you can do more with the machine but it is more money too! Pretty much if you hit a limit, you did something wrong.

[racedirector]

Thanks guys. Have changed plans for a few things, now tying the VFD and everything together with a safety relay. The proxies will be lift protection and limits, if they trip the vfd will shut down automatically as will the motors. I kept thinking the limits were close to 0,0 which they aren't on this machine seeing as 0,0 is about 50mm away.

Working on a new schematic as we speak....