Voltage and current testing

Darth Voltar

Hi:

I need to measure 0 to 350vac and 0 to 15 amps with about 1% accuracy.· My plans are to make a test console for testing pole mount power transformers.· I am going to use a servo controller variac to increse and decrease voltage.· I know how to write servo code, but I am clueless on metering with Parallax. Does anyone have a clue about this type of metering?

stamptrol

Darth,

Use a metering transducer to both isolate your stamp from the high voltage and give you a low voltage DC ( 0 - 10v is common) which you can convert to 0 - 5v with a voltage divider and feed into the A/D you'll be using with the stamp. The 2-channel chip that Parallax sells will get you started quite nicely.

Similarly, a current transducer will give you a DC signal proportional to the AC current.

Have a look at the Omega Engineering web catalog for some possibilities.

This is a good application of the stamp if done with care and attention to the safety issues. Things like lock-outs, warning lights and fail-safe circuitry should be in your design from the get go.

Cheers

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Tom Sisk

http://www.siskconsult.com
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