Show C Series input module value on waveform.

[ZohaibRamzane]

In Labview FPGA, I am reading the value of NI 9201(mount on chassis) channel and trying to show it on waveform?

Its giving me an error ''Type not supported in Current Target''.

How can i fix this? I need to show the value on a plot.

[crossrulz · Accepted solution]

Charts make ZERO sense on an FPGA application.  FPGAs are hardware.  What you should be doing is use a DMA FIFO to pass the readings to your RT.  You can use the remote front panel on the RT, but in a real application you will want to use a Network Stream or TCP/IP connection to then pass the data to your PC for logging and display.

[ZohaibRamzane]

Hi crossrulz,

Thank you for the solution.

I have little searched on what you suggested.

Can you tell me about the 2nd part of your solution;

''but in a real application you will want to use a Network Stream or TCP/IP connection to then pass the data to your PC for logging and display.''

Why i need TCP/IP connection to pass data to my PC for logging and display? Why DMA FIFO communication from FPGA to RT is not sufficient?

[GerdW]

Hi Zohaib,

have you read any of the AppNotes (and other documents from NI) on programming LabVIEW for RT and FPGA?

Have you studied the example projects coming with RT and FPGA modules?

They all show the approach as suggested by crossrulz: send data from FPGA to RT, then send data from RT to your PC using network connection.

[crossrulz]

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@ZohaibRamzane wrote:

Why i need TCP/IP connection to pass data to my PC for logging and display? Why DMA FIFO communication from FPGA to RT is not sufficient?

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A cRIO is a stand-alone device that does a specific task.  Generally speaking, a cRIO does not have a GUI (yes, the 904x series have the capability to use HMIs).  So you should use a Windows PC for your GUI that interfaces with the cRIO.  And since space on a cRIO is often limited, logging is typically done on the PC as well.

So additional resources:

Understanding Communication Options Between the Windows HMI, RT Processor, and FPGA

LabVIEW for CompactRIO Developer's Guide

[ZohaibRamzane]

Hi crossrulz,

I am trying to display my module values on waveform chart. For this i have used FIFO Write in fpga target. Now i am writing code for reading the fifo values in RT main. I dont know how to create FIFO Read for reading the fifo fpga target so that i can display them on chart.

Code pictures are attached.

Kindly help. 

[GerdW]

Hi Zohaib,

did you go through those Training resource to actually learn about LabVIEW/RT and LabVIEW/FPGA?

Did you examine the example projects coming with LabVIEW?

You need to select a FPGA build/VI/bitfile at the FPGAOpenReference function. I guess that is explained in the training resources…

[ZohaibRamzane]

I have added the OPEN reference fpga vi but i am not able to add FIFO Read to read values provided by fifo write in fpga vi.

Kindly have a look at code.

Thank you.

[crossrulz]

In the RT target, there should be an FPGA palette.  In there should be a Method node, or maybe even a FIFO Read node (it's been a little while since I was heavy in cRIO).

[ZohaibRamzane]

I am reading voltage across pt100. At roon temperature about 8 'C , it value is 109mV. I am using 9201 module whose ADC resolution is 12 bit.The waveform i am getting in labview is not stable.  My question is, is it due to low resolution of my module? If it is,which resolution will be good for measuring +-10V including low voltage as +-50mV. 

Measuring waveform is attached.