回應： Averaging pmt signal and strange signal shift problem with recording

[thh25]

Hello

I'm a researcher at UCL and am quite new to Labview. I have a PMT and i've successfully created a program to read/show and write the data. From the signal I need the average pk to pk value and the average mean value. Is there any way I tell labview to average the signal out then display it and then write it to the file?

Also, I came across a weird problem. I have split the output signal of the PMT to an oscilloscope and the daq card. When I press record in labview I see a shift in the signal seen on the oscilloscope and labview records that shift. Why is this happening? I'm guessing the circuits of the daq and pmt are not completely isolated so how could I solve this problem?

Any help is really appreciated because I'm quite clueless about what to do next

Thank You

thh

[Andy.G]

Hello THH,

You could use the probability and statistics pallet found in the functions menu under mathematics, this will contain a mean value function which you could feed your data into. As for writing the data to a file I have attached a simple VI I'm am about to post as a community example that can help you understand how to format text files.

As for the problems you are having with the signal shifting, this could be due to a few reasons. The first is an impedance mis-match between the scope and DAQ card, you can check our website for the specifications of your card. The Second reason could be a ground loop issue, you could solve this using an opto-isolator circuit.

Hope this helps

Kind Regards

[Suraj_Singh]

Hello THH, 

I am trying to control the PMT using LabVIEW, and I am not that proficient in LabVIEW. 

Would you be able to share your LabVIEW code with me? 

after that based on requirement I can rewrite the code as well. 

Thank you 

THH