LabVIEW 8.6 and OpenChoice Play Together ?

[dickyoung]

We have a Tek TDS2014 scope in the lab, and want to be able to capture traces from it, for inclusion into Excel spreadsheets and Word documents. The amount of “fiddling” with the Instrument Drivers and with the Explorer which I have done thus far have led me to believe that the best I can do with the straight SubVIs is to read out a file containing the waveform points in 8-bit 2’s Compliment notation, which I then have to scale before it means anything. On the other hand, I have noticed that Tek has a program called Openchoice which purports to allow the user to capture DSO displays for simple export into Excel or Word. Fair enough, I thought, so I downloaded the program. But before installing it, I began reading with great concern how many folks were having conflicts because Openchoice is expecting the TekVISA to be the main one, not the NI VISA which LabVIEW installs. I have already written a batch of VIs which have greatly aided in our automated data collection here in the lab, and I certainly don’t want to jeopardize their proper operation. Who could give me the “straight scoop” on the canonically correct way to make LabVIEW (8.6) and Tek’s Openchoice coexist on the same PC ?

[Dennis_Knutson]

I don't know anything about OpenChoice but the driver for the scope (assuming tktds1k2k) does everything except the save to Excel format. Don't understand why you think you have to scale the results from the scope read. You're also not reading a file. You are reading directly from the scope. There is a shipping example that you should look at. The one I have is called TKTDS1K2K Example and to save the data, you just have to wire an Export Waveforms to Spreadsheet File function to the Scaled Graph output.

[dickyoung]

Ahh...the error in my thinking was that all the output blocks would be included in the TKTDS1K2K library itself: Thanks for pointing out the Waveform to File block, this was the first time I'd had a chance to use it. (I am still coming up to speed, though I suppose you guessed that.)

I have indeed now tried pasting that block into the Example and running (see attached), but I get the following error:

"Scan From String (arg 1) in TKTDS1K2K Scale Waveform Array.vi->TKTDS1K2K Example_PlusExportToSpread.vi"

I have not altered what was inside the Scale Waveform Array block, so I'm not sure what it's unhappy with.

[dickyoung]

OK, I have had the chance to single-step through the Example VI, and everything seems to be going pretty well until, inside the Scale Waveform Array VI, the flow hits the 2nd block from the top, which apparently is supposed to do something with an input string which was pattern-matched to "WFMP;XZE". It is at that point that the Error gets generated, and apparently it keeps any sensible data from being fed to where it can be output. I have enclosed the output file, which obviously contains no meaningful data.

[dickyoung]

OK, I ended up finding my own solution for what was happening. By stepping through the Example VI from the TKTDS1K2K library, and noting what values are on the wires at each step, it became obvious that the Waveform Preamble which came out of the Tek2014 was using the LONGER VERSION of the commands, such as ":WFMPRE:XZERO", but the Scale Waveform Array SubVI contains pattern matches for the ABBREVIATED versions of those commands, such as “:WFMP:XZE” Of course, it now makes perfect sense that the Pattern Match fails, and nothing but zeros comes out due to the error. I made a customized version of the Scale Waveform Array block, which looks for the longer parameter renderings, and now the trace captures correctly and displays on the front panel of the Example VI. I can also hook up the block which runs the output to a file and have verified I can pull it into Excel, though I have to generate my own Time Axis.