ramp voltage generation

[basimss]

Hi all,

Can I create a ramp AO voltage using NI USB 7856R? Or do I have to integrate it with some labview program for ramp? If then how can I do it?

[Bob_Schor]

I'm pretty sure you have to (programmatically) tell it what you want it to do.  I think NI is actively working on a version of their hardware that will predict the waveform the user wants (such as a ramp, with parameters), but I expect that's a few years away.  Until then, you probably have to send it the ramp waveform you wish to output.

Bob Schor

[basimss]

Hi bob,

Thanks for your reply. I am attaching a picture of inbuilt analog output program for NI usb 7856r can you tell me how to make it ramp? How do I integrate it?

[GerdW]

Hi basimass,

create the ramp data in your host VI.

Then send the AO data from your host to your FPGA target.

There are a lot of functions in the Signal processing functions palette, I guess one of the will fit your needs…

[basimss]

Hi

I put ramp equation to the connector fpga and I got a signal like ramp. Now I want to slowly rise the ramp, I mean 10v/s. I put a timer but its not working. Any suggestion? Attaching image of what I have done.

[Terry_ALE]

If you are comfortable with it, I suggest you generate the waveform in the FPGA.

Can you provide parameters of the ramp?  Levels, ramp time, number of steps, does it need to repeat?

[GerdW]

Hi basimss,

Think DATAFLOW!

Your wait function is pretty useless regarding those for loops. When you want to slow down those loops you need to place the wait inside the loops...

[basimss]

Hi,

Actually what I want to create is s ramp which rises 1v/s ,using fpga Ni usb 7856R ,which can be observed using oscilloscope and when I click stop it should show a constant value.

[GerdW]

Hi basim,

some simple pseudocode:

// t1 = loop iteration time in seconds
rampspeed := 1   // 1 V/s
ao := 0
step := rampspeed * t1
REPEAT
  ao := ao + step
  wait(t1)
UNTIL "stop button"

Looks really simple to me.

(In your image you don't even place the timing in the right place…)

[basimss]

Hi

It will be helpful if you give me some labview programs( block diagram) that could work since I am new to this.