F28335

Kamran Zeb

I am sensing 230 voltage with using the LV25-P sensor for ADC of F28335 board. I studied different papers, Like the one attached linked herewith, in which the multiply with 26. I am confused how?. Can somebody share the correct way of scaling/calibration in Matlab/Simulink. Hoping a positive reply.

v2.pdf

over 5 years ago

0 Ramesh Ramamoorthy over 5 years ago

TI__Mastermind 27240 points

You may be able to find the answer to it in Matlab tech forum, forwarding your query to Matlab.

0 Brian McKay over 5 years ago

Mastermind 9005 points

The output of the ADC block should be in the range of 0-4096 (12-bit), which is probably in a uint16 datatype. I don't know where this model comes from, but maybe the DC offset and gain is trying to scale this so the max value is 2^16 ~ 66536? That is just a guess.

For better help, you probably need to contact the author of the paper to get an explanation on why the Gain blocks (with 26) are needed). I don't think MathWorks or TI tech support can assist here, as we didn't author the paper.

Cheers,

-Brian

0 Kamran Zeb over 5 years ago in reply to Brian McKay

Prodigy 115 points

Dear Brian Mckay

Can you share with me the correct way of scaling/calibration ADC in Matlab/Simulink.

0 Brian McKay over 5 years ago in reply to Kamran Zeb

Mastermind 9005 points

Typically you do SW scaling exactly like the model shows: add/subtract an offset and multiply by a gain. I just don't know why the model in the image selects a gain of 26.

-b

0 Kamran Zeb over 5 years ago in reply to Brian McKay

Prodigy 115 points

Is there any example you can share with me?

0 Brian McKay over 5 years ago in reply to Kamran Zeb

Mastermind 9005 points

I am attach a simple Simulink example of SW scaling via zipfile. I built it in Release R2018a (since that is what I have). The format is identical to what is shown in the model.

-b

scaling_example_zip.7z