Sensor connect to SCXI 1314

[Jenson7]

Hi, 

I'm a new user and want to connect SRP PT 420 pressure transmitter (http://www.srpcontrol.com/v/vspfiles/files/SRP/PT420.pdf) into our SCXI 1314.  The sensor has two wires (red for positive and blue for negative) which I use to connect to S+ and S- in one of channels. However, when I checked it in Measure Explore, the data are not right (I built analog input for current 4-20ma). Did I connect them right? Did I miss some details?

Should I use external power for the sensor? 

Thanks so much if someone can help me. 

[Jorr-El]

Hi Jenson7,

What do you mean that the data points are not right? Are they close? Are they nowhere near what you're expecting? Are you putting in a known value (like from a calibrator?)

The SCXI 1314 is a terminal block for the SCXI 1520, which is a strain gauge or Wheatstone bridge-based sensor input device. Are you using an SCXI 1520 with the 1314?

Also, what kind of coupling are you configuring your module to use? Are you using AC coupling? If you can provide some more information as to your hardware configurations and setup, we will be able to offer more assistance. Thanks!

Jason O.

Applications Engineer

National Instruments

[Jenson7]

Thanks so much Jason!

We have all the equipment, SCXI 1314, SCXI 1520 and other related equipment. Actually we successfully connect for other seven pressure transducers (one quarter bridge sensor, red for power positive, black for power negative (to our power source) and white for s+ and green for s- for SCXI 1314). There is one channel left so I try to connect for the sensor (this sensor is different from those seven sensors) mentioned in this post (output 4-20mA with two wires, red for supply positive and blue line for supply negative said in datasheet for this sensor). This sensor is used successfully with our old DA and please see the attachment for the circuit. However, I want to synchronize this sensor with other seven. That's why I try to connect with our ni equipment. Please see figure 2 which shows our connection for SCXI 1314 which didn't work.

I know it doesn't work because we increase the pressure the current doesn't change at all.

Do we still use the same connection setup as Figure 1 for SCXI 1314? What's your suggestion?

Thanks!!!