RTD Temperature Controller

[drcricket]

I am a newbie in c programming. I am using LTC2452 as my external ADC and Atmega16 as my Micro. The temperature values will then be displayed on a 2*16 LCD. I want to use SPI interface to program my temperature values from a voltage reading to a degrees reading. Need some help pls....

 

[sabouras]

i hope that will be helpful to your problem
**broken link removed**

 

[drcricket]

i hope that will be helpful to your problem
**broken link removed**

Hi,
Thanks for the helping me with the SPI interfacing. Do you know how to calculate the temperature values from the ADC output. Is there an equation to include in the main code??

 

[sabouras]

of course. There is a very help-full application note from microchip.
**broken link removed**
You could find all equation and consideration you need to be accurate in measurement.

 

[drcricket]

How would I include that equation in the maincode? Im confused with generating the temperature values using the equations..

 

[sabouras]

at the application note page page 2 exist the circuit that the microchip propose. In that circuit you are able to measure the voltage across the RTD sensor. As the application notes refers the equation for that is Vrtd=Vref*(ADC_Output)/(2^15 -1)=Vref*(ADC_OUTPUT)/32768. So you could see the variation of the voltage across the sensor.
From the manufacture of RTD you see that variation in which temperature be made. So you know the temperature.
The Vref you know it so it will be a constant. The ADC_output you could read it and the result will be matched with a table which contains temperature versus voltages or resistance changes.