Current measurements from a computer

On 16 Aug 2006 19:00:33 -0700, in message , "MIke Brown" scribed:

What do you mean? Are you saying you want to log a series of measurements to your computer via an RS-232 interface? If so, you should be able to easily find data logging devices that can do this for you. For instance:

Umm, ok, so you want to set up your computer device to do virtual real-time readouts as the DMM is logging? Reading the promo for the above device seems to show that it comes with the software that does exactly that. The vendor could be contacted for specifics.

Yes, well, I don't want to be rude here (heaven knows I'm *very* good at it), but I did a web search on , and the above link was the first hit.

"MIke Brown" wrote in news: snipped-for-privacy@m73g2000cwd.googlegroups.com:

The only reason to bring a PC into the picture is if you want to log the data.

If all you want is live readings of voltage or current, buy a digital multimeter. You'll get accurate readings, have a useful (indispensable) piece of test gear, and save yourself a lot of trouble trying to make your own.

Example:

On Thu, 17 Aug 2006 02:29:46 -0000, in message , Jim Land scribed:

Well, that's not the only reason, but the other reasons I'm thinking of might be beyond the scope of the newsgroup.

Hi, Mike. Just about all of the RS-232 capable handheld DMMs have DC and AC current ranges. Most of them can be set to spew the display numbers at fixed intervals (usually once a second or so).

As an example, the one sold at Radio Shack (Model: 22-812, $69.99 USD ea.) does both. By default, it just spits out the reading every second in real time once you start it with pressing the SELECT and RANGE buttons together. The meter also comes with software for data logging, but if you are capable of programming an RS-232 port, you can go ahead and use the data as it becomes available.

Far easier to just buy it than going through the rigors of reinventing the wheel by making one.

Good luck Chris

Not exactly what you asked for, but Dataq has a starter kit with a 4-channel 10-bit ADC that connects to the serial port and comes with data logging software for only US$24.95.

The ADC ranges are +/-10 VDC, so you'd need to add your own current-to-voltage converter ahead of this.

(No affiliation, just recognize a bargain. They used to give these things away for free... and it looks like maybe they still do for high school science fairs.)

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

To actually measure though, should be scrape away some of the rs232 cable and stick his probes there. ? And since - I think - current is measured in series, would he have to cut the cable /cut an extension cable. ?

q_q snipped-for-privacy@yahoo.co.uk wrote in news:1156034979.970921.319440@

The OP didn't say he wanted to measure voltage or current at his RS232 outlet. He said he wanted to connect a voltmeter (measuring a voltage somewhere else) to his PC through the RS232 connector.

The point is, why pass measurement data from a voltmeter to a PC? What good does that do? Maybe if you want to log measurements every five minutes for a week.