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Measuring thermocouple temperature using EVAL-ADuCM360

Question asked by khj@agramkow.com on Nov 4, 2013
Latest reply on Nov 5, 2013 by ABuda

Hi all

 

I am trying to measure a temperature using the EVAL-ADuCM360 evaluation board and a type T thermocouple connected to AIN2 ( + ) and AIN3 ( - ) using the example software "CN0221". My problem is that I get a wrong readout in the hyperterminal window, see picture below.

hyperterminal.png

I get an error on ADC1, which I have tracked to register 0x40030080, indicating a conversion error status bit because of either overrange or underrange.

 

As it can be seen, the RTD resistance is measured at 175 ohms, which clearly is wrong, as the RTD is a 100 ohm resistor, which I have measured to be at 110 ohm at room-temperature. I think that this large ohmic value could be the reason for this overrange error.

 

I have tried to upload the example software "RTD_Demo" to the board, which then measures the correct RTD value and RTD temperature.

 

My question is the:

Are there any known errors in the the example software, when calculating the RTD temperature? Or do I need to change somthing in the software, when using it in this way?

 

 

Thank you

 

Best regards:

Karsten H. Jørgensen

Denmark

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