In my previous blog post I finished by expressing my hope that I'd be able to automate the steps I manually described for loading arbitrary waveforms into the 33622A Waveform Generator using BenchVue's Test Flow application. After some investigation it looks like I will be able to do that, however, it will not be as easy as I was led to believe. Keysight advertises BenchVue as a platform that allows users to capture data from their instruments without using any programming. Well, in my case that does not seem to be entirely true. Although many instrument controls can be programmed with simple click and drop ease, not all functions are supported in the click and drop environment.
The screen shot below shows BenchVue with the Pro version of the Function Generator app running on the left side and the Test Flow application running on the right side. Look for controls, text boxes and buttons that are outlined in orange on the left hand side of the screen. Anything outlined in orange can be clicked, dragged, and dropped into the Test Flow application on the right. You can see that I have dropped a Set Channel 1:Waveform " command into the test flow. It is the blue box at the top of the sequence. The programmed parameter is set to Arb, because I want to load an arbitrary waveform from internal 33622A memory.. Notice that none of the Arb name controls on the left are outlined in orange. That means I can't drag them over to the test flow sequence on the right. That is disappointing. So, I can program selection of an Arb waveform in Test Flow, but I can't specify which Arb waveform I want to load. That means I'm limited to whatever Arb waveform is currently in the 33622A's volatile memory. Huh, that is annoying. (Side note to anyone from Keysight reading this: If I am missing something here, please let me know, otherwise, as a suggestion, could you please think about adding this functionality to the next release? Thanks in advance.)
So, one step into my first experience with Test Flow and I hit a brick wall. Not to be discouraged, I poked around looking for some other way to get my intended test sequence set up.
NOTE: At this point in writing this blog entry BenchVue informed me that a new version was available for download. I stopped to allow the update to proceed. It took 5 attempts to get the update to fully download and execute, however, on the 5th try and a day later, the update succeeded. My system has now been updated from release 3.6.1608.29 to release 3.71611.22.
Because I could not use drag and drop functionality to select a specific arbitrary waveform, I looked for another way to accomplish this task that is essential to my test objectives. I surmised I would have to insert some manual script statements or something similar. I found the "Show More Block" button below the BenchVue Test Flow title line intriguing and clicked on it. Well, clicking on that button revealed a whole goody packed treasure trove of blocks to explore. See the screen capture below.
Although it seems to me that the number of drag and drop options is quite restricted in the function generator application of Test Flow, there are plenty of useful blocks to work with under "More Blocks". Under Advanced, as shown in the screen capture above, there are blocks to add Standard Commands for Programmable Instruments (SCPI) manually, or with help of Command Expert. Full disclosure: I have never used SCPI but, I have wanted to for some time now, so I decided to explore Command Expert. Clicking and dragging Command Expert into the test flow sequence, then clicking on the icon to launch Command Expert, brings up the application shown below, after a rather too lengthy wait (BenchVue, in general , seems to be a rather sluggish application). After a few clicks to add libraries for each of my connected instruments, I quickly navigated through the available commands until I came upon a couple of compound commands that looked like they might do the trick: MMEMory:LOAD:DATA, and SOURce:Function:ARBitrary, as shown in the screen capture below.
To see if I was correct, I first configured the 33622A manually to output a sine wave, then clicked on Add Step & Execute. The command sequence worked! The MAX_Red_B.arb waveform was loaded into volatile memory. The SCPI error, shown in red above suggests to me that I had previously loaded the waveform, and that I may not need to repeat that step. More experimentation is in order.
I think I have explored BenchVue, the Pro applications for the function generator and DMM, Test Flow, and Command Expert enough to post a complete review in Road Test. I have also played with the Android and Apple BenchVue apps and will include details about those in my full review. The USB and Ethernet interfaces on my N9322C spectrum analyzer are still not working, so it will be a while longer before I can report on the Pro Spectrum Analyzer app. I'll continue to work with SCPI to build up the full test sequence I had planned to develop for this Road Test and report on progress in a future blog post.
Slainte!
