LabView FPGA - Ramp Signal Generation

[sfk009]

Hi, 

I am using a USB-7845R and LabView FPGA to create a ramp signal that upon receiving a threshold voltage value from AI 0 it steps via a user-defined voltage value until the end voltage is reached at which point resets to the starting voltage value. I am running into some knowledge limitation in terms of how to complete this correctly. Additionally, I am getting errors suggesting these lines are not compatible with my current FPGA target? Any suggestions would be greatly appreciated. 

[Bob_Schor]

You need to learn basic LabVIEW. 

• Structures like While, For, Event, etc. have an edge on the left side where data comes into the Structure (on a "wire") and an edge on the right side where data goes out of the Structure (also on a wire).  For the most part, data goes in on something called a "Tunnel" (which has several types, depending if it is changed as data flows across the Structure boundary) or via a Shift Register, where what goes in on the right-hand (output) edge appears (if the structure "loops") as an input from the left-hand (input) edge.
• For example, consider a For Loop with 10 wired to "N", the number of loops to run.  Put a Shift Register on the left edge, wire numeric 0 (from the outside of the For loop) into the Shift Register, and inside the For loop, connect the two Shift Registers together, putting an "Increment" on the wire so what comes out is one more than what goes in.  Wire an Indicator on the right (output) side of the For loop to the Shift register, and run the code.  What do you expect to see on the Indicator? 

Now look at (and fix) your code.

Bob Schor

[sfk009]

Hi Bob, 

Thank you very much for your reply. I will certainly work on learning LabView. In the meantime I have adjusted the diagram as shown below. I believe I am still not getting the correct/intended behavior. The goal is as analog input receives some voltage above the threshold, the function should step up by the "step size" and after reaching some final voltage value reset to its initial value. Could you advise on next steps? I assume I will need some aspect that when the threshold is reached, a reset will occur.

Thanks again for your help. 

[sfk009]

Hi Bob, 

I forgot to attach the files. 

[GerdW]

Hi sfk,

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@sfk009 wrote:

I believe I am still not getting the correct/intended behavior. The goal is as analog input receives some voltage above the threshold, the function should step up by the "step size" and after reaching some final voltage value reset to its initial value. Could you advise on next steps? I assume I will need some aspect that when the threshold is reached, a reset will occur.

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• When you want to change to AO voltage "continuously" then you should place the IO node inside the loop: THINK DATAFLOW!
• You just need to check for your "final voltage value" condition and act upon the result of that check… (Hint: comparison and case structure)