How to get gain adjust from multiple strain gauges

[ClaireJ]

Hello

We are using multiple strain gauges and using "DAQmx Perform Shunt Calibration (strain).vi" to perform shunt calibrations. We would like to output the gain adjust factor used by the "DAQmx Perform Shunt Calibration (strain).vi" for each gauge. We have had success using a property node (see attached images 1 and 2); however, when we try to use the same method to attain the gain adjust factor from other strain gauges (image 3), the readouts are always 0 (visible in image 2).

If anybody could provide insight regarding how to obtain the gain adjust for multiple gauges it would be very much appreciated.

Cheers

Bart Scicchitano

(using his supervisors account with her permission)

[ClaireJ]

Sorry. I seem to have attached the wrong files by mistake. The images I refer to in the original post are attached below. That is;

Image 1 - Use of property node to obtain gain factor from single strain gauge

Image 2 - Front panel output of property node from first strain gauge, and second strain gauge in series

Image 3 - Use of property node to obtain gain factor from two strain gauges in series

Cheers

Bart

[dstrandb · Accepted solution]

Hi Bart, 

You may be getting 0 because there are multiple channels within the same task, so the property node doesn't know which one to read. You can set the active channel using the Active Channel property node. Place a DAQmx Channel Property Node and select ActiveChan from the drop down list. Give this a try, and see if you can read multiple gain factors. 

[ClaireJ]

Hi David

Thank you for your response. It seems to be working now. One thing I found with this solution is that the ActiveChans block has to be at the top of the property node. I have attached an image of what I'm talking about.

Cheers

Bart

[dstrandb]

Hi Bart,

I'm glad to hear it's working. As you've discovered with property nodes, they are executed from top to bottom, so that's why the Active Chan property has to be set at the top of the property node.