EVAL-AD7124-8SDZ calibration

Hi Van Toan Iot ,

You may refer to this thread: (+) AD7124 calibration steps - Q&A - Precision ADCs - EngineerZone (analog.com).

If you have further questions, don't hesitate to ask/reply to this thread. 

Thanks and regards,

Rod

Thank you for responding.
I tried but no success. The reason is probably because CJC is not working properly. Gain of CJC channel = 1 so the app does not allow calibration. When I took the sample, CJC always returned -242 degrees Celsius. That's absurd

I believe that inside the red circle I have circled is a CJC sensor. Is that true?

Do I only need to perform either Internal calibration or system calibration, or do I have to perform both?

Hi Van Toan Iot ,

Apologies for missing the thread. 

Yes, what you encircled is a CJC sensor.

Can you please confirm if you are following the same setup as below? The figure below shows how to correctly setup the AD7124 for thermocouple applications. 

You may find this demo tutorial from your AD7124 EVAL+ app.

From the AD7124 EVAL+, click on Help>Demo Tutorials>Thermocouple to view the thermocouple demo tutorial which may help to correctly setup thermocouple on the ADC. The demo tutorial also provides configurations settings for the AD7124 when using it in thermocouple applications. 

Let us know if the readings are still off, even after setting up the thermocouple based on the demo tutorial. 

Thanks and regards,

Rod

Hello RAdante ,

I actually did as you instructed. In demo mode I chose thermocouple.

Looks like my CJC has a problem.

Hello RAdante 

Another problem is that the filter can only filter out 50hz noise when fADC<=50hz. Is there any way to solve this problem?

I enabled only the channel 0, In the Filter_0 I setting the FS_0 = 192 (100hz).

Hi Van Toan Iot ,

Can you confirm if you have the resistors and connectors set up on the terminal blocks of your EVB the same as shown in the thermocouple configuration I provided? This includes connecting a wire from AIN1 to AIN4, connecting AIN5 to REFIN+, connecting a 5.11kOhm resistor acros REFIN+ and REFIN-, and a 250Ohm resistor across REFIN- and AGND. Can you also confirm if the the links/jumpers are connected/disconnected according to the thermocouple configuration demo? 

May we know what filter are you using? Have you tried configuring the device using the Sinc4 50 Hz and 60 Hz Rejection?