On 2 Jan 2008 at 6:15, [EMAIL PROTECTED] wrote: What I'm looking at is the arc voltage signal from my plasma cutter. It is 300vdc max.
> A simple voltage divider on any inputs greater than 10v will work > fine. If you mean voltage divider as a kind of voltage supply > regulator then no, don't do it. Most especially ADCs. I also assume > you are not talking about sampling audio with this ADC but data > acquisition? Audio sampling needs to be done with a real codec IC. > Standard ADC's sampling audio are really poor quality due to aliasing > artifacts and other issues. The difference between say a burr-brown > pcm codec (audio) and the ADC's you mention are *clearly* heard, > speaking personally. My thought was to use a simple resistor circuit to divide the voltage. By 5-20k do you mean the total resistance of the circuit? The input impedance of the card I would use is <20K http://web3.automationdirect.com/static/specs/f004ad2.pdf > Btw: The impedance of the ADC input can slightly affect the value of > the voltage divider. You can find the impedance in the datasheet and > adjust your ladder if needed...in most cases the impedance is > negligable for most people. Also, lower overall impedance of the > dividor will make the ADC input impedance more negligable, but will > draw more power. 5-20k is prob suitable. laser sensors that I've used for work are very accurate and use triangulation to figure the distance. I'm not sure how the arc would effect the laser. It would have to be mounted parallel to the cutting head but up above it out of the way on the Z axis somewhere. > I am not sure what kind of distance sensing could be done, but I am > interested in it too. I think sonic wouldn't be accurate enough. Laser > would but I don't know how to do that yet, but sounds awesome. ;) > Anything else? I know many people are just using bump probes to do 3d > scanning. --- simple and digital. > > C A bump probe would work for initial height setting. Thanks John ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
