Connecting Thermistor and Transducer to NI9219 or NI9221

[bricekim88]

Hello,

I am very new to DAQ system and I am having few problems with what appears to be a simple setup from parts in my lab

It seems like that the previous student bought parts and was able to successfully record the data, however with change in lab environment and lab setting I have to start building a new DAQ system and a new Labview project to record temeprature and pressure.

These are the parts previous students bought

[3-wire thermistor (OL-703) from Omega

http://www.omega.com/pptst/OL-703.html] 

[Pressure transducer,PX906

http://www.omega.com/pptst/PX906.html] 

[K-type thermocouples] 

[NI9219, and NI9221 decked to cDAQ-9174 which is plugged into computer]

For the pressure transducer, it requires 10Vdc so I wired it to external voltage source and connected +S and -S to the NI9219 Positive and negative input signal port. but when I tried to test the transducer, as shown in the attached picture, it is giving me erros. I adjusted values and selected Vex source to external (since I am supplying voltage from outer source for the tranducer I am thinking this was the correct value) and Vex Value to 10 (since it requires 10Vdc). I was also wondering if my signal range is inputted correctly (30mV/V * 10V = 3000).

For the thermistor, it is at the moment connected to thermistor meter and when I contacted omega, I was told that I could use it's analog output to connect to DAQ analog input. the analog out from thermistor meter has ports for Volt and RTN (which I am not sure where to connect on NI9219). I was also thinking of directly connecting thermistor to NI9219. The thermistor I have is 3-wired with +S, -S and +R. or shoud I just use K-type thermocouple I have (Is it even possible?). I need help on pluging it to NI9219.

Any suggestion, reading material or basic help are much appreciated. I am very new to this and don't have anyone to help me or walk through this besides this forum and NI support team. I've spent many hours for past few days trying to setup this simple system and am struggle big time.

Thank you in advance.

[TamMou]

Hi Bricekim,

Regarding the temperature recordings, you can use the K-type thermocouple and connect it to the NI 9219 terminals 1 (T+) and 2 (T-).

For the pressure transducer, the NI 9219 does not accept external power supply (Vex Source) for the pressure transducer but only the internal one at 2.5 V and the NI 9221 cannot be used with full-bridge. One solution could be to use another card, i.e. NI 9237, which allows internal excitation of 10V as required by your pressure transducer.

http://sine.ni.com/nips/cds/view/p/lang/en/nid/209891

Besides your signal range should be set as 0 - 30 mV (not 0-3k) since you get 30 mV at 10 Vdc power supply according to the pressure transducer specifications.

[bricekim88]

Thank you very much for the reply,

I was wondering what the unit for "Signal Input Range" is.

is it in mV or V?

[TamMou]

The unit for the signal input range is in V. But you can type 30m (for 30mV or 0.03 V) in the box.