PE Pressure Transducer measurement using NI 9234 and LabVIEW FPGA

[YousefB]

Hi, 

I have a Kistler Type 603B pressure transducer that I want to measure as an analog input on a Waveform Chart. The transducer is a PE type (charge output), as such I've connected it to a Kistler 5015 charge amplifier, which in turn is connected to a NI 9234 +/- 5V Analog Input module. The NI 9234 has the ability to incorporate IEPE signal conditioning but as I'm using the charge amplifier already I don't believe I need that. Attached is the FPGA VI that I'm using to extract the data, however as I'm new to this king of programming I'm unsure how to get from the I/O Item Configuration to the Waveform chart. Mod8 is the NI 9234 and AI0 is what the charge amplifier is connected to.

If anyone can advise on this I'd be very grateful.

Thanks

[NPowl]

Hi Helix,

Here is my understanding of the problem so far:

You are connecting a Transducer to a Charge Amplifier, and then reading data via a NI 9234 card. You are unsure how to program the data from this card into the chart. I am assuming you are using a cRIO if you are attempting to use FPGA, please correct me if I'm wrong here.

To gain an understanding of the programming, I would recommend reading this tutorial: http://www.ni.com/tutorial/54219/en/

The article contains a discussion of programming modes and also instructions on how to create a basic logging application with FPGA (or links to using it as just Real-Time if you determine this is the mode you need). This is a great starting point for people new to the programming!

If you are a University student, you will have access to online self-paced training. I recommend having a look at this to get more familiar with LabVIEW. 

I hope this helps!

Kind regards,

Nick Powley

[YousefB]

Hi Nick,

Thanks for your response. Yes, I am using a cRIO 9014 Real-Time Controller.

I've followed the tutorial you sent me but I'm struggling with one thing - as I've only got one Analog Input (AI0), I'm not building an array of inputs and therefore I haven't got anything to index the For Loop. This falls under step 6 of the "4. Create a basic logging application with LabVIEW FPGA Interface" section. How should I get around this issue? Can it be replaced with a While Loop instead?

Thanks

[NPowl]

Hi Yousef,

If you're just using one input, you shouldn't need to run the For Loop. All that loop is doing is giving every row of the array into the Element function (and also checking if data overflows - this probably isn't an issue for you if you are only using one channel). 

Hope this helps!

[YousefB]

Ok thanks, I'll give that a go.

Another thing is configuring the FIFO - am I right in saying that hovering the cursor over the wire from Mod8/AI0 in Context Help gives me the word length as 24 and integer word length as 4? That's how I've configured the FIFO with Fixed Point data but I'm not sure if it's right. Please see pics.

Thanks again!

[NPowl]

That seems correct from my knowledge, but I must admit I'm not the most versed in this. Try it and see if it works! 🙂