Electrobud,
For the thermocouple measurement to be accurate, the two leads of the thermocouple and the cold-junction measurement must all be at the same temperature. Generally, the PCB is designed so that all three are close together, so the temperature…
Dany,
Just to make sure that you have this the ADS1118EVM is built like a thermocouple measurement application and you can find the user's guide here:
There is also a short cookbook circuit here:
Additionally you can find an application note…
Shreenidhi,
The ADS1118 should work fine for a thermocouple measurement. There's a lot of information about using this device for a thermocouple measurement. The ADS1118EVM has a thermocouple connection to make temperature measurements. The customer…
I would like to translate this question.
I'm using ADS1118EVM. Sometimes I will observe temperature jump from 27.2℃ to 0 as shown below. But the actual temperature should remain constant. Why?
And what does dynamic, static mean?
Bob,
I have the ADS1118EVM.
Good point about the power. The ADS1118EVM is being powered by 5V coming from the NI USB-8451. DOUT has a 5K pull up to that 5V source also which is why it has a 5V swing. On the other hand, the NI USB-8451 is programmed…
Nipun,
I think either of your solutions will work.
For the first, the Recommend Operating Conditions (page 6 of the datasheet) does say that the input voltage for either analog input should stay between GND and VDD. However, with 20mV outside the range…
Gaurav, I'm not sure I understand your question. What do want to accomplish with asymmetric biasing? The combination of R1 and R2 can change the common-mode voltage of the ADC inpu, but won't affect the differential voltage measurement. Normally, we…
Jose,
Using the resistors for biasing doesn't mean that you can't use an anti-aliasing filter on the front end. You can still use one like this:
The ADS1118EVM uses the same type of front end.
As for your other comments, generally, I've worked…
Melissa, You can use an instrumentation amplifier to measure a thermocouple. I did find an old post that discusses biasing the thermocouple and putting it into gain: e2e.ti.com/.../223435 The amplifier is set to a gain of 1001, but you may need to change…
Timothy,
I see an error, but its a bit different than you expect. The thermocouple voltage reads 0xD5, which translates to 213d and a reading for 1.664mV. Using the conversion table, this would be 41.3°C only if your cold-junction were at 0°C.…
