0-300VDC to Binary

[Big John T]

I need to take a 0-300VDC signal from my Hypertherm 1250 and convert that to a binary weighted input and send it to my parallel port. I'm thinking 8 bits...

I'm thinking that a voltage divider to scale the voltage down to 0-10 then an ADC circuit with ttl output in binary. There must be a brizzilan ADC chips out there... Anyone have any ideas on this?

Thanks
John

[vger]

John,

Yeah, there are a bunch of em. Just a couple of thoughts here. You will most likely want to optically isolate the circuit from the PC in both directions.
The divider method should do fine for getting the voltage down to usable level, just use high enough value resistors so as not to overload the source.

A quick search gave me a chip available from "microchip". It's the TC850

Yeah I know it's 15 bit plus sign, but it has a H/L select input to select the upper or lower byte. here is a link to the datasheet.

http://ww1.microchip.com/downloads/e...Doc/21479C.pdf

http://www.microchip.com is their home page

Not sure how much the thing is, they may "sample" you one for free, not sure.

Steve

[Al_The_Man]

There is the H11F1 opto with analogue 'Resistive' output that may be a suitable isolator if scaled right.
Al.