Which DAQ do you suggest?

[rinpocse91]

Hi,

I posted few days ago about it, but i changed my concept.

I would like to create a real-time PID regulation in LabView. There is a hydraulic cylinder with a load cell in the end of the rod.

I would like  type the force value in LabView, for example: 10kN and via DAQ, i would like to do real-time PID regulation.

The load cell and the hydraulic pressure relief can also receive tension signal.

Which DAQ do you suggest? I guess I need an AIO DAQ, but there are so many.

Thanks!

[crossrulz · Accepted solution]

I highly recommend you give your local NI representative a call and have a meeting with them.  Discuss all of your requirements with them and they can help you choose the hardware you need.

[RavensFan]

I don't know what you mean by a tension signal.  Are you talking about tension and compression in the load cell?

Load cells usually output a full bridge strain gage signal.  So you'd need a DAQ device that can supply excitation and read small millivolt level values.  A lot of pressure sensors are also using a strain gage bridge to read pressure.  So the same needs apply.

If you have a level of signal conditioning after those devices, then the strain gage bridge signal can be converted to either a voltage or current signal.  That opens up more possibillities for different DAQ devices.

What frequency do you need to read these signals?

[rinpocse91]

Sry, my english is not good 🙂

I mean the output signal from the load cell is voltage. I guess. Actually i do not understand it, because i dont see the output signal range.  So  I attached the load cell's sheet. maybe You can help me. 🙂

Thank you.

[RavensFan]

It looks to me like a regular strain gage bridge based load cell.  It talks about the sensitivity being 2 mV/V and the bridge being 350 ohms.

[rinpocse91]

Then I need something from here:

http://sine.ni.com/np/app/main/p/bot/no/ap/daq/lang/en/pg/1/sn/n25:device,n17:daq,n24:cDAQ,n36:12/

thanks!

[rinpocse91]

Thanks your help!

So, there is a bridge based load cell. If I use Ni-simulated DAQmx,  in MAX i have to choose Analog input/bridge, or Voltage?

Thankyou.

[RavensFan]

Analog input bridge (might be under "strain").

[rinpocse91]

yes, i found it, thanks.

But i have some new question. 🙂

in MAX, i create a new simulated DAQ,I choose, bridge/channel. I choose, mv/v and the others,thats ok. But what does "m" and "Vex value" mean? 

Furthermore, how can i import this simulated DAQ to LAbView? If I go to labview and insert a DAQ, that is a new one daq, and not this one.

Khank you very much! I appreciate your helps!

[RavensFan]

m means milli or 10e-3.  So you hav +25 millistrain to -25 millistrain.

Vex means Voltage-Excitation.

You create a task of whatever name you want that shows up in Data Neighborhood.

Later when you get the real device, create another task.  Use the new taskname in your code.

Or delete the old task and create the new real task with the same name and you shouldn't have to change the task in your LV code.