Data Recorder

[alansimpson]

I need a device to record torque on a device running at 30 RPM for 1 rev. I will probably use a torque sensor with anologue output and a 500 step encoder. I will need to record and log analogue value for every pulse of the encoder and output data to spreadsheet. Is there a suitable data recorder that could log 500 values at 900Khz?
Speed may not be uniform so an oscilloscope is not suitable.

 

[btrueblood]

Does the device make one turn, or is it turning continuously?

Assuming it's turning continuously, and you therefore need a stand-alone datalogger (battery operated that you will attach to the rotating equipment), I doubt you will find a packaged (retail) self-contained datalogger capable of that high a speed, and the triggering from an encoder signal. There are some pretty simple ways to make a device to do the job, using PIC or similar microcontrollers.

You might think about how many turns the device needs to make for your test - if you can start, measure, and stop within less than 5 minutes, you are only talking about 150 revolutions. A 10-foot length of wire, running down or near the center of the shaft, and held stationary externally, could easily absorb 150 twists without breaking or stretching enough to bias the signal. Record the signal on a standard data acquisition board on a PC.

 

[GregLocock]

Where does 900 kHz come from? That's a bit high.

Anyway, guessing you really need to sample at 1 kHz or less any instrumentation quality DAT recorder will cope, or even the sound card on your PC, if it has no low frequency roll-off.

Another alternative would be an A/D card.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[alansimpson]

Sorry that should be 250Hz. Only out by a factor of 3600. Thought it looked a bit high.

The continuous rotation is not an issue since I am using a rotating torque sensor rather than reaction sensor.

I just need a black box which can log an anologue value for each pulse of encoder for 500 consecutive pulses and transmit data to PC for analysis.

 

[GregLocock]

battery powered radio modem, if you want real time. However your cheapest option is likely to be solid state storage given the small amount of data, then download it later. I bet Fluke make a DVM that'll do the job. Sorry, no real idea on sources.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[btrueblood]

Um, as I read it Greg, he doesn't need the battery-powered rotating-with-the-machine logger after all, just a sittin'-on-the-table type. Or am I missing something (again)? Your earlier post is then correct (e.g. any old DAQ card will do).

alansimpson, See National Instruments, or Measurement Computing. You may need to write a little bit of C++ code to make it all work.