Signal conditioning and amplified circuit for high precision NTC sensors

Thread Starter

Omar Moroccii

Joined Feb 23, 2018
6
Hello all,
I am working on a project where I need to read reading from a 10Kohm NTC sensor.
The accuracy has to be 0.015 °C with a resolution of 0.001 °C.
The problem is that due to lack of time, I need a ready built device or circuit that will provide me with the direct input from NTC.
I currently have found the INA330 Chip from Texas insturement, and this product https://www.picotech.com/data-logger/pt-104/high-accuracy-temperature-daq for RTDs.

I was wondering if there are similar products out there.
 

GopherT

Joined Nov 23, 2012
7,983
Hello all,
I am working on a project where I need to read reading from a 10Kohm NTC sensor.
The accuracy has to be 0.015 °C with a resolution of 0.001 °C.
The problem is that due to lack of time, I need a ready built device or circuit that will provide me with the direct input from NTC.
I currently have found the INA330 Chip from Texas insturement, and this product https://www.picotech.com/data-logger/pt-104/high-accuracy-temperature-daq for RTDs.

I was wondering if there are similar products out there.
If you need that kind of precision, you will also need to keep the rest of the circuit in a temperature controlled box. PN junctions are quite sensitive to temp changes vs the numbers you give (diode will shift about 2mV/°C)
 

Thread Starter

Omar Moroccii

Joined Feb 23, 2018
6
If you need that kind of precision, you will also need to keep the rest of the circuit in a temperature controlled box. PN junctions are quite sensitive to temp changes vs the numbers you give (diode will shift about 2mV/°C)
I am building a thermal shielding around the test set-up to minimize the influence of the ambient temperature on the electricalcircuit
 

GopherT

Joined Nov 23, 2012
7,983
The sensors in the link have a specified accuracy of ±0.1°C; a far cry from 0.015°C :(.
Accuracy is easily corrected for with calibration.
The important part is repeatability and drift.

Depending on the application, measuring change is way more important that absolute temp.
 

OBW0549

Joined Mar 2, 2015
2,986
Guys, I think I didn't make my question clear.
My question is if there are commericially available ICs or devices which I can directly hook up to NTC without having to build the amplifying and conditioning PCB circuit myself.
An IC (like the INA330 you mentioned in your first post) isn't going to do you any good, as you'd have to build an appropriate circuit around it on a PC board. Nor have I been able to find any ready-made boards you could use.

An example is :https://www.picotech.com/data-logger/pt-104/high-accuracy-temperature-daq
Are there any other similar devices or IC?
The closest thing I could find to what you're looking for seems to be the Model 5831 from Omega Engineering. Note that the Picotech data logger is for platinum RTDs, not NTCs.
 

Reloadron

Joined Jan 15, 2015
4,514
Guys, I think I didn't make my question clear.
My question is if there are commericially available ICs or devices which I can directly hook up to NTC without having to build the amplifying and conditioning PCB circuit myself.

An example is :https://www.picotech.com/data-logger/pt-104/high-accuracy-temperature-daq
Are there any other similar devices or IC?
Yes, from any of a dozen or more manufacturers. Depends on how much you want to spend. Do you only want display or control W/ or W/O display? If you want control then which type control? Here is one example, an Omega DP 41 which depending on options can be interfaced to a PC.

The specifications you want, even with calibration are not likely. Some of the best uncertainties I have seen have been 0.01 degrees C with high end PRTs with charted calibration. Manufacturers like Instrulab.

Ron
 
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Thread Starter

Omar Moroccii

Joined Feb 23, 2018
6
Yes, from any of a dozen or more manufacturers. Depends on how much you want to spend. Do you only want display or control W/ or W/O display? If you want control then which type control? Here is one example, an Omega DP 41 which depending on options can be interfaced to a PC.

Ron
Price has a low weight compared to specifications, so I'm not focusing on price.
I am not sure what you mean by control ? as in change the sensing range etc?
The Omega DP 41 has an accuracy of 0,2C and resolution of 0.01, which is too low for my application
 
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