How to adjust the value of the digital potentiometer such that it outputs a desired value of voltage.

[Chaitanya]

Hi all, I have a digital potentiometer in a circuit which needs to be adjusted to control the voltage it receives. Its a 2 channel 256 position AD5207 dig pot. I need to adjust the wiper position of the dig pot(which we need to do using labview)such that it outputs a particular desired voltage value.For example, if the input to the pot is 200mV, then we need to adjust the pot such that it sends out a value of 50mV. How can we do that?? Please help. The DAQ iam using is PCI-MIO-16E-4. Thank you......Ausuri

[wha@atmel]

Hi

I think your task is very simple - had a look to AD5207-Datasheet.
Find attached some samples of SPI-Interface ( in this case using the Printerport - but no problem to switch to your MIO-card ).
With these ideas, how to handle a SPI-Interface you should be able to succeed.......

regards
wha

[Chaitanya]

Hi Mr.Wha,
Thank you for your help. But I am just a beginner in labview and data acquisition.I could not follow the order of the files that u attached and their purpose.Can u please brief me in what order should i follow the files(i found 4 files) and the overall purpose of the files.I mean, i want to know what actually u r doing with those vi's? This might seem very basic to you, but i am just learning labview stuff.Sorry for wasting your valuable time.
Thank you
Chaitanya Ausuri

[Ben]

Hi Chaitanya,

We never know who our audience is when we answer these questions. There has ben quite a few occations when I have insulted people because my answers was too basic.

The creattion dates on the files show that "project xx SPI.vi" has the latest mod date.

Open it and take a look at the diagram.

Put the VI in execution-highlighting mode (click the light bulb) and the run the VI and watch what happens.

There are pictures included in the diagram that illustates what is happening.

If you have specific questions after watching the VI run, ask away.

This is a wonderful example!

I would have charged big bucks for this example.

Good work Wha!

Ben

[wha@atmel]

....thank you for the flowers Ben,

I expect, that typical beginners should look into an example.vi in your described way - and learn how it works.
Meanwhile, because I was interested in these dig. pot. myself, I have cutted one of my old SPI's and reused in AD5207.vi - see attachment.
It should also work for AD8402 digital pot.
I have made it as simple as possible........

Regards
wha

[Chaitanya]

Hi Mr.wha,
Thank you very much. I am trying to understand the files u attached.I really appreciate your interest in attaching me some example files.I will back with any doubts(which I think I am sure to get!) regarding the files,if u dont mind!Thank you again.
Chaitanya