How can I do a start ramp?

[pablosan]

Hello,

I'm trying to do a start ramp in a FPGA Target and i don't know how to do it.

It is for speed motor control.

Somebady can help me?

[GerdW]

Hi pablo,

for a ramp you usually have a start value, end value and a given time. You increment your start value with a certain time delay until you reached your end value…

You will need to do the very same on your FPGA!

[aputman]

There is a "Ramp Pattern" VI that will output an array of values based on your start, end and either # of samples or delta change. 

[crossrulz]

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@aputman wrote:

There is a "Ramp Pattern" VI that will output an array of values based on your start, end and either # of samples or delta change. 

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Read more carefully.  We are in the FPGA realm.  That function does not exist there.

[aputman]

My bad.  I am not familiar with FPGA.  

[pablosan]

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crossrulz escribió:

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@aputman wrote:

There is a "Ramp Pattern" VI that will output an array of values based on your start, end and either # of samples or delta change. 

---

Read more carefully.  We are in the FPGA realm.  That function does not exist there.

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That's my problem. In the FPGA realm i don't know how to do it.

[GerdW]

Hi Pablosan,

dy = (endvalue - startvalue)*dt/t
y = startvalue
while y < endvalue
   output(y)
   y := y + dy
   wait(dt)
wend

Looks pretty simple to generate a ramp…

[pablosan]

but how can i do with block diagram? i don't understand how to do the timer!

[GerdW]

Hi pablosan,

what's the problem with using a wait function? Even the FPGA knows how to wait for a certain amount of time…

[pablosan]

I do this, but i don't know how to change de shift register in double to FTP.