Comparator circuit thoughts....

[kevlar129bp]

mackrackit,

No more confusion than before . Actually, the way you described the voltage scaling makes more sense to me now. As far as the torch voltage is concerned, maybe I added confusion from the beginning by not stating what would be a good baseline hysteresis to go with. After trying to get my head around the scaling, I started looking at the numbers more, and in doing that, I think a resolution of 1 volt change at the torch would be more than ok. That being said, that's where I figured using a torch value ranging from 0 - 256 Vdc...

8 bit ADC
4 Vdc Vref
Vdc per ADC count : 4 / 256 = .015625
Torch Vdc scale : 1:64
Torch Vdc per ADC count : .015625 * 64 = 1 Vdc

Ex: Torch Vdc = 115

ADC counts * Vdc per ADC count = ADC Vdc Now

115 * .015625 = 1.796875 Vdc

1.796875 * Torch Vdc scale = Torch Vdc

1.796875 * 64 = 115 Torch Vdc

So... for every 1 Vdc change at the torch, there will be a 1 count change at the ADC... correct?

If this is the case, coding for this arrangment should be way easier?
Am I making this easier or harder on myself? I think it's sinking in slowly but surely. Thanks for assisting me on my brain fryer!

Chris

[mackrackit]

I think you got it.

[kevlar129bp]

Thanks mackrackit,

I'll hack away at a bit of the code and see what I get... Will you be around for some assistance in that arena, when I get to that point?

Thank you again... TONS!

Chris

[mackrackit]

We are always here....

Start the testing with a POT to simulated the torch.

Which PIC are you going to use?

[kevlar129bp]

mackrackit,

In looking at my options, I think the 16F88 is going to do the trick. I'de like to plan ahead to do something like this on the front of the cnc pc. I dunno, let me know what you think... And again, thank you so much for your help. I'm working through the code as we speak

Chris

[mackrackit]

At this point I would say whatever you have laying around. The 88 is good for starters. Might run out of memory or pins later but might not.

But how are you writing code if you have not picked a PIC?

[kevlar129bp]

I have opted to write the code for the '88. Hopefully I don't run out of space . I'll keep you posted on that one.