NI SCXI 1314

[Aquaphire]

Hello all,

I'm not sure that anyone here can help since this is a Labview forum...

I have here 3 "boxes" for data aquisition. NI SCXI 1000, NI SCXI 1520 and NI SCXI 1314. The 1314 connects to the 1520 which connects to the 1000 which itself connects directly to the computer.

I have attempted to connect a strain Gauge to the SCXI 1314, but during data aquisition using measure and automation, there is absolutely no variation when its stimulated. I've tried taking a voltmeter to try to measure the excitation voltage to no avail...

Anyone have any suggestions for troubleshooting or..anything else...

thanks!

[mikeporter]

Can you read it through MAX?

Mike...

[Sean_C.]

Hello,

Try setting up a DAQmx Strain Task in Measurement and Automation Explorer (MAX). Right-click on Data Neighborhood and select Create New... In the new window, highlight DAQmx Task and select Next. Then follow the task configuration wizard through a few steps to set up your strain channel. Make sure you select the correct values for Excititation Source and Voltage, Bridge Configuration, and Gauge Resistance. Once complete, you can press the Test button at the top of the screen to test your new strain channel.

If you still cannot read any variation in strain, try using a different channel on the SCXI-1314. If that doesn't work, try a new strain gauge, then a new SCXI-1314, and then a new SCXI-1520, if available.

By the way... What version of NI-DAQ are you using? Are you using NI-DAQmx or Traditional NI-DAQ? With which programming language will you be building your application? What type of DAQ device do you have connected to you SCXI system?

Let me know your results.

Regards,
Sean C.

[Aquaphire]

Hey sean, sorry for the super slow answer. I had thought that the post was closed and didnt bother re-checking.

I set up the DAQmx strain task in MAX> I think i selected everything correctly.

Range: 10000, -10000 (micro)E

Gauge resistance:348.88 Ohms

Gauge factor: 2.11

Lead resistance: 348 (<-- not sure)

I tried various channels and 2 different strain gauges and both have the same value of about: -3600 to -3700 (micro) E

Using NIDAQ 6.9, MAX  ... actually im not sure what is what... and which is useful for labview. The only thing I used so far is NIDAQ.

The hardware devices that are connected to the computer were all named above (SCXI models)

thanks.

Hello,

Try setting up a DAQmx Strain Task in Measurement and Automation Explorer (MAX). Right-click on Data Neighborhood and select Create New... In the new window, highlight DAQmx Task and select Next. Then follow the task configuration wizard through a few steps to set up your strain channel. Make sure you select the correct values for Excititation Source and Voltage, Bridge Configuration, and Gauge Resistance. Once complete, you can press the Test button at the top of the screen to test your new strain channel.

If you still cannot read any variation in strain, try using a different channel on the SCXI-1314. If that doesn't work, try a new strain gauge, then a new SCXI-1314, and then a new SCXI-1520, if available.

By the way... What version of NI-DAQ are you using? Are you using NI-DAQmx or Traditional NI-DAQ? With which programming language will you be building your application? What type of DAQ device do you have connected to you SCXI system?

Let me know your results.

Regards,
Sean C.

[Aquaphire]

Can no one help me,...... ! 😞 lol. I hate this strain gauge thing.

[Sean_C.]

Hello Aquaphire,

Try setting the Lead Resistance to 0.  It is unlikely that the leads (a.k.a. wires) have as much resistance as the actual strain gauge.

Regards,
Sean C.

[Aquaphire]

now, the reading is -1700 (mico)E

--> Is that good or bad?

thanks

[Sean_C.]

Hello,

Are you able to see any variation of the signal when you apply strain to your strain gauge?  If so, then I would run a null calibration on your strain gauge to get rid of the -1700 microstrain offset.  What are you setting the excitation voltage to?  Verify that you are getting that voltage from the P+ and P- teminals.

If you still cannot see any variation on the signal try using a different DAQ device to control your SCXI system.

You might also want to check all cables and modules for bent pins.  Please let me know your results.

Regards,

Sean C.

[Aquaphire]

Hello sean, I actually managed to figure things out.

The hardware installation was not well made and conclusively the readings were incorect.

Now I manage to do everything pretty much  normally, but somehow the "null" function doesnt seem to work. It works until I try to see the graph using MAX.... then it resets itself to 1400 or somethign equivalent.

thanks,

[Sean_C.]

"Now I manage to do everything pretty much  normally, but somehow the "null" function doesnt seem to work. It works until I try to see the graph using MAX.... then it resets itself to 1400 or somethign equivalent."

Which "null" function are you referring to?  The VI in LabVIEW or the utility in MAX?  Try running the null offset in MAX and see if it works correctly.

Regards,

Sean C.