Using the Lab Oscilloscopes to Save Data

Into the Computer (Blue Benches Only)

 

⋅               Turn on the computer and the HP 54645D Oscilloscope

⋅               On the Oscilloscope, get a picture of what you want to save. That is, make sure that the oscilloscope is showing everything you want to seen in MATLAB, plus it is usually helpful to get a little more. If you are careful, you can set the triggering so that what you get in the file will start at time zero. Try it or ask your TA's how.

⋅               Once you have the picture you want on the scope, start the HP Benchlink package on the computer. You do this by clicking on Start - Programs - Benchlink - HP Benchlink Scope (In times past you used to have to start the computer program before you turned on the 'scope. They appear to have fixed this now, but if you run into a problem with the computer freezing, start the program first, then turn on the 'scope, then have the program search for instruments.)

⋅               If you are asked to search for instruments, make sure the 'scope is on, and click search, then select the 'scope and press OK

⋅               Once you're going, Click on Waveform > New, which brings up a dialog window which tells you the program is about to read data points from the 'scope. You can select which sources to read, corresponding to A1 and A2 of the 'scope. You can also tell it how many points to read by clicking on Options. Make sure that this is set to 500 or 1000 (anything less is too choppy and anything more becomes prohibitive as far as disk space or for MATLAB to process.) Then click OK to get the figure.

⋅               At this point you can print, but it's better to use MATLAB where you can add titles, legends and labels, so you want to save the data as a file. To do this click on
Waveform > Save as Time, Amplitude and choose a place to save the file (your disk) and save it as a filename.csv file (if it's trying to save it as another name, it won't work).

⋅               At this point you can open it up with any text editor (like notepad) and edit the contents. The header to the file is junk, so it's profitable to open up the file and delete any words or white space before the columns of numbers start. Resave the file under a new name with the ending filename.txt

⋅               At this point your file will be ready to use in MATLAB, so refer to the MATLAB instructions on how to use this data.