Strain VI - Logging data

[Andy S]

Hi all,

Just 2 really quick questions. I am using the example VI for strain (the first one which includes calibration) and I want to log the data it reads until the VI is stopped. I am assuming I need to use the "write to file" function but I'm not too sure where to wire it to. Also I need to factor all the final strain readings by 2, where and how would be the best to do that?

Thanks again,

Andy 

[jyang72211]

Attach the vi of what you have so far.

Yik

[david.bolt]

Dear Andy

Please find attached a VI that I think will solve your problem. This logs data until the stop is pressed and factors the results by 2. I have used a case structure, so that data is only written when it is above 1.You can delete this and always write any data (including 0, or adjust this to maybe 0.0001,to aviod logging no data as you wish). I hope this helps

Message Edited by david.bolt on 03-03-2010 06:07 AM

[Andy S]

Thanks David,

Unfortunately I don't have access to the internet at the computer I am taking my readings with and I don't have the software installed anywhere else so I wont be able to get a look at it until tomorrow. The VI I am planning to use will be based on, if not identical to, the example titled "Cont Acq Strain Samples (with Calibration) - NI 9237", would I be able to add your VI into that to log the data?

Apologies for all the questions, It's the first time I've had a look at the software and need my VI ready for the start of next week for testing!

Many Thanks,

Andy 

[Andy S]

Hi again,

I've attached the VI that I plan to use but with all the shunt calibration and offset null I cant seem to work out where to connect the "write to measurement file" to the rest of my VI!

If anyone can fix it up for me that would be great!

Thanks,

Andy

[david.bolt]

Dear Andy

Thanks for posting your VI but this really is not the best way to do this at all. The strain data control I used in my VI was just for an example. The coding you have is not synchronised for logging the data as that part of your VI is in a seperate while loop. Add the 'Write to Measurement File' to the chart data coming out of the DAQmx read. Please find attached what I mean. Have you considered doing some LabVIEW training?

Message Edited by david.bolt on 03-08-2010 08:50 AM

[Andy S]

Thanks David,

I thought it was something to do with it being in a separate loop, maybe that's why I couldn't get it to work! I'l get a look at your VI tomorrow and hopefully that'l do the trick! The reason I haven't undertaking any training is because this is only for a university project which comes to an end very soon! But some training in the future might be an idea!

Thanks,

Andy