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Help on Discrete Transfer Function Direct VI

Jahy,

 

Is there a reason you can't use the CD&Sim Transfer function in place of the FPGA code?

Steven Gloor
Staff Customer Engineer - CTA, CLD
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Message 11 of 18
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Steve,

 

I want to realize a transfer function in FPGA, to provide faster calculating speed than CD&Sim Transfer function in RT system.

 

Jahy.

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Message 12 of 18
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So what value are you expecting to see in the DiscreteTF-RT VI? It seems to me that it is behaving correctly.

Steven Gloor
Staff Customer Engineer - CTA, CLD
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Message 13 of 18
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Steve,

 

The expectation is that the output of Discrete Transfer Function Direct in FPGA and that of Integrator in RT are exactly the same. Both the results are shown on the front panel of RT as 'outputDiscrete' and 'outputContinuous'.

 

In my program, The 'Loop Timer' in FPGA could slow down the increase of the output, but I can't make its output the same as the integrator in RT. Do you get the same result with your machine?

 

Jahy

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Message 14 of 18
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The two functions are executing at different rates. If you add the Discrete Transfer Function Direct to the CD&Sim loop directly, you will ensure the functions are executing at the same rate. Doing this shows that there is a difference in the order of magnitude on the output (I see outputDiscrete = 10 x outputContinuous). 

 

See the attached code for what I did to get this result.

Steven Gloor
Staff Customer Engineer - CTA, CLD
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Message 15 of 18
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Here is a modified version of the VI where the responses match. 

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Message 16 of 18
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Steve,

 

Thank you for you help. Can you do me one more favor? I use LabVIEW 2010, and can't open the program with LabVIEW 2014. Can you tell me how you adjust the program in detail and make a picture of screen of the program?

 

Jahy.

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Message 17 of 18
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Here they are saved for 2010. I've also attached screenshots of Southern_Cross's modified version.

Steven Gloor
Staff Customer Engineer - CTA, CLD
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Message 18 of 18
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