Pressure Transducer calibration

[Ali123]

I have two pressure transducers from omegadyne. I was trying to calibrate the Transducers via linear equations. The problem is that when I put the second transducer line slope and y-intercept, the first one (line slope and y-intercept) changes automatically to the second setting. Transducers are attached to two different channels. I can not have two different equations for the two transducers. I appreciate it if someone has any solution to this.

Regards 

[Mike.F]

Hi,

Can you please be more specific with the problem description?

I can't understand which option changes automatically to the previous setting.

Regards,

Miguel Fonseca

Applications Engineer

National Instruments

[Ali123]

Sorry for being confusing. I actually have two pressure transducer hooked up to my DAQ. As a result I have to linear equations to convert the output of the transducers (mv) to psi.  When I want to calibrate the transducers and (by which I mean inserting the slope and the y intercept of the line) for the second transducer, the first one equation (slope and y-intercept) changes automatically to the second one equation. I can not put in two different equations for two transducers. Labview automatically updates the slope and intercept of the other transducer scaling equation.

Regards,

---

@Mike.F wrote:

Hi,

Can you please be more specific with the problem description?

I can't understand which option changes automatically to the previous setting.

Regards,

Miguel Fonseca

Applications Engineer

National Instruments

---

[chuggins1434]

Are your transducers are of the same scale? (0-1", or whatever)  If they are and you're having to use different slopes... well, then I'd suggest better pressure transducers!    (I use nothing but Setra transducers in my lab) 

If they are different scales then you can either take raw data from the inputs and calculate the proper results in your code, or you can setup custom scales in the DAQ Assistant for each type of transducer you're using. 

Good luck!

Chad

[Ali123]

Chad,

Thanks for your comment. I actually use Omegadyne transducers and both are of the same scale (0-100 mv) (0-1000psi). I did define the slope and y-intercept in the DAQ assistant properties for them. My problem is that I can not give it two different line equations for two transducers. Once I put in the line equation for one of them, the other one update itself automatically. I appreciate it if you have any comment.

Thanks,

Ali

[chuggins1434 · Accepted solution]

Ali,

When you're in the DAQ Assistant, under the configuration tab... in the Voltage Input Setup area there is a Custom Scaling pull down.  If you pull that down you can select Create New and this will allow you to setup a custom scale for each transducer if you wish.  Just assign the custom scale to the appropriate channel once you've created the custom scale.  

If you're using the same range transducers and they have differnt slopes... I'd send them back and buy some that are within a few percentage points of each other across the range.  No one should be selling you two trans ducers that have the same range that do not use the same slope... the intercept I can see needing some adjustment, but not the slope!  ...just my opinion.  I've sent plenty of equipment back that either didn't perform or wasn't linear in its response.  ...again, just my opinion.

Enjoy!

Chad

[Ali123]

Chad,

Thanks for your help. I created a new custom scale the way you mentioned and it works, I can put in two different equations for my transducers. I used to have only one profile. The slopes are literally very close to each other but still not the same. Anyway I do appreciate your help and advice.

Regards,

Ali