Pmod ad5 chaning sample rate

[Jrlin]

Hello,

I have two questions

1) I wanted to change my Pmod AD5 sample rate from default ~6 samples/Sec to 4.8Ks/S.

I know you have to use the AD7193.SetRegisterValue(    ,      ,     ,      )

But having trouble understanding manual.

2) My input signal range is from 0 to 5v but the Pmod max range setting is +-2.5V.

Can I shift my voltage setting range so I can input a 0to 5v signal?

 

Thanks for your help

 

[Alex]

Hi, here are some inputs.

1) Sorry, where did you find the input voltage is only 2.5V. By looking at the AD7193 spec, it is should 4V at max http://www.analog.com/media/en/technical-documentation/data-sheets/AD7193.pdf. I didn't see any this of info in the Pmod spec (https://www.digilentinc.com/Pmods/Digilent-Pmod_ Interface_Specification.pdf) either. It looks like the reference voltage is 2.5V only. 

2) Have you taken a look at https://wiki.analog.com/resources/tools-software/uc-drivers/microchip/ad7193.#software_project_setup2

[JColvin]

Hi,

Alex is right, the Pmod can only get up to a range of +/- 4V in bipolar mode because the programmable gain array (pg 32 of the datasheet) has an overhead of 1.25V. The reference voltage (Avdd) can be supplied through REFIN2+ and REFIN2- pins on the J2 header of the PmodAD5.

As for changing your sample rate, you would need to change the Mode Register to adjust the "filter output data rate select bits" from the default of 96 to 1 to get a much faster output data rate. With the inherent settling time associated with the on-board chip, I'm not sure you will be able to get as high of a output rate as you want, but I can't confirm or deny this. 

Either way, it sounds like you're using the Analog Devices library for this chip, so you would need to contact them to find out how to best utilize it.

Let me know if you have any more questions.

Thanks,
JColvin