Best Hardware for temperature measurement using thermocouple

[jay3112]

Hey everyone,

I am working on a project where I have to measure the surface temperature using T- type thermocouple and store the data of 4 hours. So, my application is of data acquisition. The voltage range and the temperature range of the thermocouple I am using is as follows: 

Temperature range:  -270 to 400 °C

Voltage range:  -6.258 to 20.872 mV

My organization has a number of NI Hardware and I am not sure which one is best suitable for my application. The list of hardware is as follows:

1. NI USRP-2935 1.2GHz to 6GHz dual RF Reciever SDR
2. NI myRIO-1900 (Includes WIFI and MSP connector)
3. NI myRIO starter and mechatronics kit
4. NI myRIO Embedded kit
5. cRIO -9063, 4 slot Integrated 667 MHz Dual-core controller and Artix-7 FGPA
6. NI 9205, 32 channel +/- 10V , 250 kZ/s, input module
7. NI 9401, 8 channel, 100 ns, TTL Digital I/O Module

In my knowledge, NI 9205 and NI 9401 are compatible with my DAQ application. But I am not sure which one to use. Please help! 

[LennartM]

Not sure what is in the My rio kits. But with the NI 9205 and NI 9401 you won't be able to measure it correctly. I would recommend a dedicated thermocouple readout unit. Like for instance the 9213.

To accurately measure the temperature you also have to know the temperature of the cold junction (the point where thermocouple wires are connected to the readout). With a standard voltage readout (like the NI 9205) you don't have this functionality.

An alternative to the very expensive 9213 is to use a converter chip, like this one: https://www.adafruit.com/product/1778. And connect it to the 9205 card. Provided that you use a type K thermocouple.

[croohcifer]

"Best" is subjective.  Out of your listed options, none will work unless you provide some external CJC as mentioned above and know how to program for your cRIO (assuming you actually can use the cRIO for your application and don't need to buy a new chassis).  If you want a cheap option that doesn't require a chassis, the NI TC-01 is a single-channel USB adapter for thermocouples.  If you want more channels, the NI 9210 module will get you four channels for a cheaper per-channel cost than the TC-01, but it will require a cDAQ or cRIO chassis.  If you need your own chassis (i.e., this temp logging isn't just an expansion on whatever you're using your listed cRIO for) and you're just doing some simple temp logging, I'd recommend the cDAQ.  A one slot model that could hold the four-channel NI 9210 costs ~$300.  There are various options, and you'd best be served by calling your local NI rep to help talk through the options if you have other questions.  Good luck!