Using Two DAQ, is it possible?

[carlosdga]

I made the circuit for the LM35 and I tested it and it seems to work fine. A group from my University own a NI USB-9008 and I´ll try to borrow it so I can test it with the Signal Express.

I noticed that the temperature response was a little bit slow, but it works for me, temperature measures with the test bank won´t change too fast during experiments.

About the pressure transducer, I´m still evaluating, but I found these ones:

http://www.astsensors.com/files/pdf/AST4100-compact-pressure-sensor.pdf  (Sorry if this is not allowed in this forum)

In my case, I´d be getting the 1-6 VDC Output (0-200 Psi range). Do you think their will work ok with the DAQ?

Do you know other transducer that could work in a better way?

Thanks for the help

[DFGray]

The input range is easily handled by the 6008, and the sensor bandwidth at maximum range is 1kHz, so you should be good.  You should not have any problems interfacing to that pressure sensor.

If you have more temperature sensors than pressure sensors, put them all on the same 6008, since they can be run much slower than the pressure sensor.

Good luck.  Sounds like fun.

[carlosdga]

I have 5 temperature sensors and 5 pressure sensors. I was thinking about putting each type of sensors on separate DAQ´s, that´s what you are saying right?

[NIquist]

Yes, it's generally better to set up any DAQ with similar type signals grouped together in a scan.  This makes it easier to collect and group your data.  Also, it is less likely that you will end up scanning a very small signal right after a large one.  This can cause problems (channel ghosting) if the gain amplifiers before the ADC don't have time to settle as some of the large signal may still be present when the smaller signal is collected.  This probably won't be an issue in your particular application but since you have enough DAQs (and channels) to segregate your signals you may as well do it.  Good Luck.

[carlosdga]

I want to take you guys, DFGray and Nlquist, for provided me all the information I requested. I couldn´t be any grateful with both of you.

Today, I had the chance to spoke with the teacher who´s in charge of the department that dispose from similar NI DAQ´s so I´ll be making the circuit tomorrow in order to amplify the output signal I´m having with the temperature sensor and test it with the one the teacher has.

I´m very excited with this project. I already finished the rehab part. So now I´m 100% focused in the data acquisition. Today I had a problem with the temperature that the sensor is displaying in the multimeter but I´m working on it.

Thanks agains for the help you have provided. In case I have any problem during the project´s development, I hope I still could get help from you because thanks to you now I´m clear with the road I had to take to make this possible.

Best regards

[NIquist]

---

@carlosdga wrote:

I want to take you guys,

---

  I hope you mean to a steak dinner or a basketball game!

[carlosdga]

Ehhh..

I´d certainly do it. But distance is kind of a problem huh?

[carlosdga]

Good day!

I´ve been testing the USB NI-6008 with the LM35 circuit (made by myself) and it works fine with the Labview. However, as seen in the first pages, I´ll be monitoring 5 temperature signals simultaneously. When I try to connect another LM35 circuit (in another channel of course), I can´t do multiple acquisition at the time, I get an error. I´m clear about the 10 KS/s sampling for the 6008, but I´m reading slow-changing values (temperatures) so it works for me, but I can´t make the Labview work with both sensors at the time.

I hope I can receive some help from you guys!

Best regards!

[GovBob]

What is the error you receive? You can only create one task per type of measurement on the board. If you are trying to create 2 tasks it won't work. Search for DAQmx syntax in the LabVIEW help if that is what you are trying to do.

Hope this helps.

[DFGray]

Post your SignalExpress project or your LabVIEW code so we can take a look at the issue.