Crio- 9004 FPGA

[vinayak1011]

I want to generate a square pulse of 25KHz in using my cRIO-9004 controller and cRIO-9104 chassis. How can I do that?

[The_Fearless_Hyena]

You'll need a digital output module like the NI 9401.

If you have the necessary hardware, are you able to set it up in the LabVIEW project? Have you programmed FPGA before? What specifically do you need help with?

[vinayak1011]

I am working with cRIO-9004 controller, cRIO-9104 chasis, and AI module cRIO-9215, AO module cRIO-9265.

I have to design a controller for boost converter. and generate a square pulse for MOSFET. my boost converter is designed for sampling freq of 25KHz.

So I need a way to design a square wave of 25KHz at the output. 

[The_Fearless_Hyena]

Hi Vinayak,

Are you planning on using the AO module to generate the square wave? That's not ideal because the 9265 only has an update rate of 100 kS/s, so you won't have any adjustment capability on frequency or duty cycle. Hopefully your MOSFET will just work with whatever you generate, because if not, you won't have a lot of options.

Have you looked in the example finder for example projects for the 9265? I'm not at my computer to check right now, but I'd bet that there is an example that will do most of what you need.

If you still need further help, please provide more details. What specifically do you need help with? You didn't really answer my questions from my last post. Are you able to set up your hardware in the LV project? Have you used LV FPGA before?

[vinayak1011]

I am actually new to LABVIEW FPGA, as well as new to LABVIEW.

But last 1 month I was just learning LabVIEW programming, and could get the simulaton results for the closed loop control of boost converter.

Now from last week I am working with LabVIEW FPGA, and i have come to know that it is much different than working with LabVIEW alone as the hardware comes into picture.

[vinayak1011]

How can I know, what frequency is suitable with my cRIO-9265 AO module?

[The_Fearless_Hyena]

To figure out the frequencies you can create, you should look at the specifications for the module. It has a max update rate of 100 kS/s. Because it takes two points to define a square wave, the fastest square wave you could generate with this module would be 50 kHz, but that won't allow for any adjustment of frequency or duty cycle.

Also, you'd have to look at the analog characteristics of the output. Specifically, what is its rise time, analog bandwidth, and settling time? A lot of signal generators will have smoothing filters to smooth out discontinuities (which is exactly what a square wave is: just a series of discontinuities) so the output may look more like a triangle wave than a square wave at high frequencies.

If you could be more specific about what you need, we could give more specific advice.

[vinayak1011]

My application is control of Boost Converter. I have to generate a square pulse of 25KHz of varying duty cycle which will facilate the control of the Boost converter model which I have made in hardware.

Can I generate this using the modules available?

So how can generate this using my cRIO-9004 controller, cRIO-9104 chasis, and cRIO-9265 AO module?

And what is the maximum frequency of square wave I can generate with varying duty cycle?