Test Stand Data Acquisition - looking for a recommended Dataq DI- unit

I have a test stand with a 1,000lbs load cell. I originally had a Dataq DI-148UP for data acquisition. Well, I can't locate that old device, been 7 or 8 years since I last used it, and it is no longer even offered by the manufacturer. Not sure whether I need to move up to the DI-155 or DI-245 (starter kits), or whether there is a strong recommendation for another device. Your insight would be greatly appreciated.

I would pick the 29 dollar DI-145 starter kit. Four channels, 10 bit resolution with 240 samples/second is all you need.

Steve G

That works fine if you have a good load cell amplifier and only want to measure thrust. Remember that a 0-5 volt output load cell amplifier reduces the system resolution to 8-bits.

Otherwise you might want more bits and more gain, and possibly a higher sampling rate.

Another option is to get a USB 24 bit LCA evaluation board from Analog Device that we discussed over a year ago. IIRC it cost $55 and came with bunch of goodies.

Bob

Bob

I use this https://jmida.com/MF-28.asp, but only because DATAQ's shipping prices to NZ were rediculous. I'd get the DATAQ equivalent of that

Thanks for responding. Considering options.


DMLappert
TRA 04246, L3

Measurement Computing USB-201 (https://www.mccdaq.com/usb-data-acquisition/USB-201.aspx) seems like a good option. 12 bit resolution and 100kS/s sample rate for $99.00 is pretty good.

Andre said:

Measurement Computing USB-201 (https://www.mccdaq.com/usb-data-acquisition/USB-201.aspx) seems like a good option. 12 bit resolution and 100kS/s sample rate for $99.00 is pretty good.

Click to expand...

This looks like a good deal. The original software was buggy but apparently has been fixed.

Today, most companies can make good DAQ hardware. Where they fail is the software which is often difficult to use or a very expensive add on.

The primary reason I recommend DATAQ is because the software is really easy to use. The disadvantage is that the hardware is far more capable than the software and the optional software to get the full speed data from the hardware can be pricey, and bring the acquisition price into the $200-$300 range. https://www.dataq.com/data-acquisition/starter-kits/

The free software supplied with the MC USB-201 is good but is restricted to 32K sps data rates. The full blown software that allows for full hardware speed is an additional $199 raising the full price to $298 which is good speed for the price. The big disadvantage of the hardware is the fixed +/- 10 Volt input range with means you may need external amplifiers for each channel or loose bit resolution in the data. https://www.mccdaq.com/td-compare.aspx

You don't get everything for nothing with any of these inexpensive digitizers.

Bob

The Dataq DI-155 would have 17lbs steps, where the DI-245 would be sub-lb. it appears whichever way I decide price tag is around $300. Darn decisions.


DMLappert
TRA 04246, L3

Look here at Analog Devices.

https://instrumentation.analog.com/en/weigh-scales/segment/im.html

https://www.analog.com/en/analog-to-digital-converters/ad-converters/ad7192/products/product.html

https://www.analog.com/en/analog-to...onverters/ad7192/products/EVAL-AD7192/eb.html

Cost is $59. I think this will work for you.

Bob

The Dataq DI-155 would have 17lbs steps

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Where did you get that figure?

Even the DI-145 which has a .02 volt max resolution could give a 2lb/step resolution, based on a 1000 lb load cell with a 10 volt output.

Steve G

Actually from whoever picked up the phone at Dataq..

Actually from whoever picked up the phone at Dataq

Click to expand...

Funny, had to be a salesperson. Hmm, should I sell him the $150 unit or the $300 one?

I still think the DI-145 is a good choice.

Steve G

Thanks Steve.. Yep.. That's what happens when one doesn't fully understand, and done the homework. Shame on me. DI-145 it is. Or are you in sales?

Anybody write a manual for data reduction yet? Would really help. The test grains need to be neutral burning and darn near perfect (ie. no bubbles).
McCreary's manual still has holes in that regard. He was going to write another edition that covered that specifically but I suspect work and life got in the way.
Kurt

No not in sales, but very familiar with the DataQ products. I currently use the discontinued DI-158U.

Would the DI-155 bring any advantage?

dmlappert
Would the DI-155 bring any advantage?

Click to expand...

Depends on how much accuracy you want and the size motors you are testing.
At 500 lbs and above the DI-145 is accurate to +/- 1% or better. At 100 lbs accurate to only +/- 4%, base on a 0 to 5 volt amp and your 1K load cell.
The DI-155 has 16 times the resolution, but do you really need that much?
If you use a 100 lb load cell on the same 100 lb motor then the DI-145 is still accurate to 1%. You could spend the 120 dollar savings on extra load cells.

Steve G

Steve

Yep or on chems. Thanks, you were a major help. DI-145 it is. Over & out.

Thanks to all that responded.

One additional note. A loadcell amp with 3 independent adjustments really helps.

1.) The basic equations for a load cell: output = scaling factor x gain x load + offset.

2.) Most load cell amplifiers have all 3 adjustment however in most designs the 3 adjustments are not independent which makes the load cell amplifier difficult to adjust and calibrate.

3.) When these values are all independently adjustable, then the output range of the amplifier can be adjusted to any ADC you have.

These load cell amplifiers prom Phillips Instruments are inexpensive at $30 and implement the INA125 manual's recommend circuit which has 3 independent adjustments. https://picom2.com/Phillips_Instruments.html

https://picom2.com/files/INA125Manual.pdf is the manual which you should read even if you do not purchase one.

Bob

Thx Bob

Thanks everyone, this tread fall right at the same time as I will start to build an hybrid test stand.

Will you do a build thread? I'm a ways from designing and building but plan to build a hybrid test stand. Any pictures appreciated.

Thanks,
StanO

StanO said:

Will you do a build thread? I'm a ways from designing and building but plan to build a hybrid test stand. Any pictures appreciated.

Thanks,
StanO

Click to expand...

If it's hybrid test stand pictures you want, try these.



And a video of the same stand with the UniStrut mounted on the wall at the MIT test cell.

[video=youtube;zE7twPkMBUs]https://www.youtube.com/watch?v=zE7twPkMBUs&list=UUMTjL8ls1VzKuujsPNJM6aw[/video]

I've never done a build thread on a test stand. I have a few photos which may or may not be useful. I have both a vertical test stand and a horizontal test stand which I use for EX-hybrid motors. I use the horizontal test stand almost exclusively.




[video=youtube;Dq6-K2pgp_g]https://www.youtube.com/watch?v=Dq6-K2pgp_g&feature=player_embedded[/video]


-->MCS

.

Love the railroad track mount!

Dataq DI-149 on its way. I tried one last time to locate the DI-148up... Finally gave up. Thanks for everyone's recommendations.

Hi all , rather than hijack this thread, I have a full post of our Hybrid test stand, and some test fires here... for those interested.
or need some ideas on test stands etc..

https://hybridrocketryforum.com/index.php/topic,474.0.html

As for Data ack and Amps, I would highly recommend the "SMOWO ST 01A" Load Cell sensor Amplifier, full bridge strain gauge transducer
Very easy to use and great quality.

https://www.ebay.com/itm/0-5V-10V-4...969?pt=LH_DefaultDomain_0&hash=item4d235565c9

EMiR said:

Hi all , rather than hijack this thread, I have a full post of our Hybrid test stand, and some test fires here... for those interested.
or need some ideas on test stands etc..

https://hybridrocketryforum.com/index.php/topic,474.0.html

Click to expand...

Sweet!!! Very nice! Thanks.

Does anyone have a cleaver way to calibrate a large-ish load cell??? I have a 10k LbF which needs to be calibrated. Im familiar with shunt resistors. Im hoping for a more direct method. I tried to make a big lever bar, but it didn't work very well.

--MCS

.

Shunt resistors calibrate the electronics, not the load cell. The only way to calibrate a load cell is with a load.

Two load cells mounted in series on a hydraulic press stand is one way to calibrate them.

Bob

My thanks to billspad, MCS and EMiR for the great pictures and links. Much appreciated! Now to the drawing board as we used to say.

StanO