CNC probe mixer question....

[G._Hoffman]

OK, so I've got two probes for my CNC machine (one for setting Z axis depth zero, and one for probing objects).  Annoyingly, they operate at opposite logic states!!!  Rather than having to reset the input every time I change probes, I want to make some kind of mixer for the two probes.  I was thinking I could just do it with a 4049 hex inverter, which would be great since I have all the parts here and wouldn't have to buy any parts, but I pretty quickly realized you can't just mix logic signals like you do analog signals.  So now I'm thinking I want to use a quad AND gate.  I'm thinking I can use one gate for each input as a buffer, and by switching the second input between logic states I'll also get the ability to switch polarity.  The third gate will be just an AND gate, and the fourth gate will be another buffer for the output (also switchable polarity).  Makes sense, or no?


Gabriel

[G._Hoffman]

Like so....

[EL34]

I can't help with the mixer

Not sure what machine controller you use
I use Mach3 and it lets me set the input ports high or low
But that may not help unless you set up two ports, one for each probe

The thing I do with touch probes is set dead centers and Z height
Mach 3 lets me create buttons on the screen and the execute VB script code that you can write yourself

It would be real easy to set up a button on the screen for each probe and just alter the code

[G._Hoffman]

I can't help with the mixer

Not sure what machine controller you use
I use Mach3 and it lets me set the input ports high or low
But that may not help unless you set up two ports, one for each probe

The thing I do with touch probes is set dead centers and Z height
Mach 3 lets me create buttons on the screen and the execute VB script code that you can write yourself

It would be real easy to set up a button on the screen for each probe and just alter the code

Yup, that's what I'm using it for too - though I would like to be able to digitize necks and the like at some point.  I've got everything set up - I've been probing for Z height for quite a while, and have used a similar setup for edge finding, but now that I've got the new probe for digitizing the mixed logic states are frustrating, and of course create an opportunity for operator error every time I change between the two.  I had to switch 3-4 times last night, and I only for got to switch once, but it caused a crash that could have been quite bad (it wasn't - I whacked the e-stop soon enough, but still...)


Gabriel

[EL34]

So, do you have any unused ports?


If not, I added a second Parallel printer port card to my machine and got some more ports that way.

[G._Hoffman]

So, do you have any unused ports?


If not, I added a second Parallel printer port card to my machine and got some more ports that way.

I don't, but Mach3 only has one input that is dedicated to a probe (yes, I know, I could use another port, but then I'd have to figure out the programing, which is not my forte!)  One chip, some resistors, and a cap would take me a LOT less time!  (Programing computers makes me feel like a moron, I'm so bad at it.  The amount of time I spend just getting a "hello world" program to work is embarrassing!)

I do have a second break out board, but I haven't got a second parallel port yet, and have other plans for those inputs at the moment.


Gabriel