I should have watched the video before replying! Sorry about that. I think it answered all my questions. A few more comments below.
Michael Hudson-Doyle <michael.hud...@linaro.org> writes: > Zach Pfeffer <zach.pfef...@linaro.org> writes: > >> Just wanted to share this with everyone. >> >> I've attached the "output" folder that the NI instrument creates for >> each test session. In the results file you'll see a text doc called >> results.txt that lists the comma delimited parameters that get >> measured followed by the measurements themselves: >> >> Current Cycle Average,Current Cycle RMS,Current Mean (DC),Current >> Negative Peak,Current Peak to Peak,Current Positive Peak,Current >> RMS,Volt Cycle Average,Volt Cycle RMS,Volt Mean (DC),Volt Negative >> Peak,Volt Peak to Peak,Volt Positive Peak,Volt RMS >> >> See: >> >> https://docs.google.com/a/linaro.org/file/d/0B3pUtxWjZbP9bFhqNGZfYzNSMWs/edit > > That actually looks fairly similar to what you get out of streamline > with the energy probe. Not too surprising I guess. Except that each line summarises a measurement, whereas with the energy probe each line summarises a sample period (i.e. 1ms). >> Included in each record is a Record Number that indexes into the >> "report directory." Each directory is marked with an index and under >> that directory is the graph associated with the data for example: >> >> https://docs.google.com/a/linaro.org/file/d/0B3pUtxWjZbP9VnVQS3M4WWx1OVk/edit >> >> In addition, controlling the instrument is super easy. You connect to >> the box over TCP/IP the you can send 5 single character commands in >> any order: 1,0,s,e,r >> >> 1 turns the power on >> 0 turns it off >> s starts a measurement >> e ends a measurement >> r records >> >> r is destructive, so if you send an r it erase the previous data >> record. The data record does survive instrument restarts (as opposed >> to having an implicit r at the start of the measurement. > > I'm not sure I entirely understand. What's the difference between "r" > and "s", aside from the fact that r erases previous data? I think 'r' should be a mnemonic for 'reset' not 'record' :-) > Is there any reason to power the device down between tests in the usual > course of things? I see here that 1/0 controls power to the device under test, not the NI hardware. I was a bit confused. I assume the VI isn't particularly connection-oriented? I mean that if you connect, send 1, disconnect, connect again and send r, the effect is the same as just connecting and sending 1 then r? We'll need to teach lava how to power control a NI-attached board then -- but that looks really easy, so I'm not at all worried about this. Is there any latency between the VI receiving the 's' byte and starting measurement? >> At any point the existing data set can simply be uploaded. > > This is just putting things into my language rather than yours I guess, > but is it correct to stay that your VI puts the output in a known > location, so other processes on the box can access it? > > I'm imagining something like the following course of events during a > test run (please forgive a certain amount of hand-waving): > > * The LAVA host sends '1' if necessary to the VI and then 'r' > * for each test case: > * The target sends 's' to the VI > * The target runs the test case > * The target send 'e' to the VI > * The LAVA host grabs the results from the VI and matches the power data > against the test results > * The host (maybe?) sends '0' to the VI. > * The results are uploaded to the dashboard and displayed in some useful > way I had this mostly right I think, apart from the stuff about 1/0, and, because of what readings.txt actually records, the "match the power data against the test results" is going to be really easy. >> One minor point. This instrument produces a lot of data, instead of >> moving all this data around, the instrument can be configured to do >> all the measurement, making the analyzed data set easier to understand >> and faster to upload. > > Yeah, I think that we'd like to just upload something like the > readings.txt file for now? Or possibly something even more derived than > that to start with... just the average power draw over a period would be > a good start! And now I see that "just the average power draw over a period" is actually what readings.txt contains :-) >> Comments and questions welcome. >> >> See it in action at: >> https://plus.google.com/u/0/104422661029399872488/posts/NU4pZ36L13U >> Cheers, mwh _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
