Data acquisition equipment advice req'd - PeachParts Mercedes-Benz Forum

Stretch · #1 09-24-2011, 05:50 AM

G'day All,

I've just "obtained" an unexpected amount of money and I'd like to blow it all on some Data acquisition equipment. I want to measure stuff.

I'd like to have something that is a little bit more advanced than a sound card attached to a PC but something that is way cheaper than a Bruel & Kjaer pulse system.

I'm only interested in measuring voltages (0 - 10V) in audible frequency ranges as time domain signals. Anti-aliasing filtering is a must. <= perhaps this is too complicated for this forum? Anyway I thought I'd give it a go!

I've got about $1000 to $1500 (USD) to spend.

If you were a bit nutty like me what would you buy?

(Sorry please only suggest data acquisition systems - not more cars / tools / strippers / holidays etc etc etc)

lutzTD · #2 09-24-2011, 08:44 AM

we use Agilent 34970A data collection systems with 20 channel Agilent 34901A multiplexer cards at work, I will have to check the available cards as the ones we use are for thermocouples, they only have two fused voltage channels. I assume it could use different cards for only voltage. It uses 20 channel plug in cards with 3 card slots. I imagine you could get one of these on feebay but I wouldnt know how to go about trusting it was still working. The software we have is for XP but I also assume that could be updated, maybe not. Anyway, they seem reliable as we have done countless DOEs on the two we have with no issues over the 7 years Ive been there.

Stretch · #3 09-24-2011, 10:57 AM

Quote:

Originally Posted by lutzTD

we use Agilent 34970A data collection systems with 20 channel Agilent 34901A multiplexer cards at work, I will have to check the available cards as the ones we use are for thermocouples, they only have two fused voltage channels. I assume it could use different cards for only voltage. It uses 20 channel plug in cards with 3 card slots. I imagine you could get one of these on feebay but I wouldnt know how to go about trusting it was still working. The software we have is for XP but I also assume that could be updated, maybe not. Anyway, they seem reliable as we have done countless DOEs on the two we have with no issues over the 7 years Ive been there.

Thanks for the tip.

That's pretty expensive stuff as it comes with calibration certificates etc - truly professional stuff. I'm wondering if there are some good cheaper brand new options out there (blowing the budget on second hand stuff - particularly electronics - goes against the grain!)...

Google often comes up with results that show these fantastic cards / chips that cost from say about $100 upwards but they seem to be bits of the system - rather than the complete system I want.

I don't really want to build my own - but may be I'll have to.

If I go down that route do you know of any good (low frequency stable) analogue low pass filter kits? Something that would decay at about 20dB / decade would be good - fixed cut off at about 10kHz would be fine - loads of these chips sample at 30kHz and higher all overkill for what I want to measure... (sorry this ramble means I'm not really looking for some super duper drops off the edge of the world decay rate in order to get as wide a frequency band width as possible)

Then I'd need a good "auto ranging" amplifier set up so I can minimise quantization errors...

Here's a better question:-

Does anyone know of a good electronics forum where I can ask these data acquisition questions?

sjh · #4 09-24-2011, 11:43 AM

I could of helped you 20+ years ago.

It's been that long since I've worked with that stuff. At that time data I/O cards were low cost and I'd stick them on a dedicated PC. The programming languages were so simple even I could write the code.

Gotta think it's WAY better now.

Stretch · #5 09-24-2011, 12:51 PM

Quote:

Originally Posted by sjh

I could of helped you 20+ years ago.

It's been that long since I've worked with that stuff. At that time data I/O cards were low cost and I'd stick them on a dedicated PC. The programming languages were so simple even I could write the code.

Gotta think it's WAY better now.

Oh it is and it isn't. If I have to I'll enhance my C++ or even java abilities... Some of the straight out of the box stuff is dongle protected Windows only - sometimes pay every year! - crappy software run stuff. Bruel & Kjaer used to (might still do) have a software reduced capability on some of their products...

...at least in the old days when they used to make hardware to last forever you could always use what you'd got...

...but then you had the choice of small house by the sea or 8 channel FFT analyser...

Stretch · #6 09-29-2011, 04:25 PM

How about a (late) mid week bump?