DAQ Setup for taking measurements from K type thermocouple, Pressure transducer, flow meter and control multiple Thermoelectrics

[dk179]

Hi all,

I am a newbie in DAQ and I have only used NI myDAQ before. Due to my inexperience, I am facing troubles selecting the correct modules that fit my needs. I am looking for a DAQ system that would be able to take measurements from multiple thermocouple, pressure transducer and flow meter and also be able to control multiple thermoelectrics. I have requested assitance from the NI staff but I am still not completely sure which modules to get. Can someone tell me what modules I need? I will try to clarify any questions.

Thermocouple 

http://www.omega.com/temperature/pdf/tc-npt.pdf

Flow meter (Input: 24Vdc   Output: 4-20mA)

http://www.bronkhorstusa.com/en/products/gas_flow_meters_and_controllers/elflow_select/

Pressure transducer (Honeywell Model TJE)

- around the same input and output of flow meter

Thermoelectrics (Probably this one, not sure yet) 30A, 270W, 15.2V

http://www.customthermoelectric.com/tecs/pdf/12711-5P31-30CZ_spec_sht_20150213.pdf

I am not sure if the DAQ can power the thermoelectrics and all the other components.

I really need some guidance and help for this. Greatly appreciate it if someone could enlighten me. Thanks a lot.

Dennis

[dk179]

Forgot to mention that I would need to control Normally closed/Normally open valve with LabVIEW as well. So I would also need to connect the valves to the DAQ. 

Solenoid high pressure valves

http://clarkcooper.com/hpv/EH50.html

Thanks for the help.

Dennis

[Henrik_Volkers]

Is the thermocouple the sensor to control the TECs?

If yes, why thermocouple? ... the range is restricted by the TECs and just in case you want to use a multiplexed multi IO  card you have to deal with µV and V (assuming a 250 Ohm resistor to read the current) that can lead to ghost signals (channel crosstalk) on multiplexed cards. 

What specs do you need (not: would like to have) for temperature control?  Again, it is possible with TCs but  usually less challenging with PT100(0) or NTCs ...

How fast do you need the control?

TECs prefer a clean DC...  but you can run them with a PWM DIO,  we used lambda power supplies with a serial bus control in the past...

I would look into the RIOs ....

(just in case you need some more IO just plug in the module needed in a (spare) free slot)

[dk179]

Hi there,

Thanks for taking the time to reply. Yes some of the thermocouples are ued to control the TECs, but not all of them. Other thermocouple are used to measure temperature for different part of the system. I only need to control temperature in the range of 0 - 40 degrees Celcius so I think TC would be sufficient. Increasing and decreasing temperature at 2 degrees C/min is my goal. My project is a little bit more complex so it is a little difficult to explain. But basically what I want to do is to increase/decrease temperature of my test gas that is circulating in my closed loop test bench at a rate of 2C/min (This is only one part of my system). Reason for choosing TECs over traditional heat exchanger is due to the space constraint that I have. 

Regarding the PWM DIO and RIO that you mentioned, I actually have no idea what they are. I will do more research on that. The NI technician recommended me their compactDAQ so I have only looked at those at the moment and I was confused by all the different modules. Sorry for my inexperience. As I said, I am really new to this stuff so please be patient with me. 🙂

Thank you so much for the help. 

[Cooking_Up_Code]

Hi dk179,

If you are looking to set up a new DAQ system using National Instruments products, I recommend you use our system advisors. You can select which kind of chassis you'd like (cRIO, cDAQ, PXI, etc.) and select modules based on your requirements for the different sensor types. For example, under the cDAQ advisor, you can select Temperature and see all the different modules used for measureing Thermocouples and RTDs. This is probably the best place to start so you can narrow down exactly what kind of modules would best suit your system. Here is the link to the advisors.

https://www.ni.com/advisor/

If you have any more questions about creating a system or would like to talk on the phone to an engineer here, feel free to call in at 1-866-275-6964 for support. You can talk to our applications and sales engineers to help figure out the best set up for your applications. Have a great day.

Paul C

Applications Engineer

National Instruments

[dk179]

Thanks for the advice. I am currently seeking assitance from one of the staff, but I just want to get more opinions from different sources while I am waiting for the staff to reply.

Thanks,

Dennis