multi-phase angle meter

yarisboy

In 2000 I needed a phase angle meter and priced one from Fluke. $2000 in '00 dollars for a single phase. I had an A/D multifunction card left over from a small business I closed so I built my own. My ISA card produced 40Ksp and let me MUX/sample three phase voltages and currents and record the data to hard drive. The Excel software of the day let me print out the data as a six trace oscilloscope would if one existed. If I had had a MATLAB license back then I would have done the post process that way. I still have the front end with the high voltage connections and CT clamps. I'm working with the Propeller now and the only part of this type of contraption I haven't played with is a data logging device. I've seen a USB storage card for the propeller sold by Parallax. Would an astute user prefer a 32 gig USB device or an SD card type of storage? I haven't used SD stuff yet (except in my camera). I own a copy of View Port. Would it be able to post process statistics of transient and steady state three phase motor response characteristics?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
MOORE'S LAW: The capabilities of electronics shall double every 18 months.
cloyd's corollary: Hardware is easy, software is hard.

Peter Jakacki

I tackled that phase angle meter stuff years ago with an MSP430 easily. As long as the clock reference was stable you could plug into a phase, take a sample, and use that for the reference. If you didn't take any more measurements in a certain period of time the reference would be considered invalid and a new reference measurement would need to be taken. This was mainly for indentifying multiple phases within a building and not so much what you are doing with motors.

Now to answer your question it would undoubtably be the SD card as the interface is a simple SPI style interface with low protocol overheads which suits the Prop nicely. Hosting any USB devices is a major pain in the butt which is why PCs mainly do that task as they need to "know" about all the different kinds of plug'n'PRAY devices. For most logging applications I've found that the basic 2GB card is way more than ample.

*Peter*