WEBVTT NOTE This file was exported by MacCaption version 7.0.13 to comply with the WebVTT specification dated March 27, 2017. 00:00:04.438 --> 00:00:07.641 align:center line:-1 position:50% size:40% We'll pick up where we left off during the last demonstration 00:00:07.641 --> 00:00:12.446 align:center line:-1 position:50% size:39% and do some further analysis on this CANbus signal. 00:00:12.446 --> 00:00:17.718 align:center line:-1 position:50% size:49% Looking at these particular bits here, this is a frame called "Brake torque," 00:00:17.718 --> 00:00:19.386 align:center line:-1 position:50% size:43% that's the name of the message. 00:00:19.386 --> 00:00:27.194 align:center line:-1 position:50% size:61% Notice at the end of the frame, there's a pulse that goes to a lower or a more dominant level. 00:00:27.194 --> 00:00:31.265 align:center line:-1 position:50% size:41% This is because after the node that generates brake torque, 00:00:31.265 --> 00:00:37.337 align:center line:-1 position:50% size:64% all other nodes will pull on the acknowledgement bit if it sees a valid frame, 00:00:37.337 --> 00:00:41.508 align:center line:-1 position:50% size:43% It pulls more current and takes it to a lower low level. 00:00:41.508 --> 00:00:46.480 align:center line:-1 position:50% size:49% It makes it easy to see if each frame is acknowledged. 00:00:46.480 --> 00:00:48.982 align:center line:-1 position:50% size:60% Look over here at the beginning of the frame. 00:00:48.982 --> 00:00:51.485 align:center line:-1 position:50% size:43% Something similar is happening. 00:00:51.485 --> 00:00:54.988 align:center line:-1 position:50% size:50% Let's zoom in on that a little bit closer, 00:00:54.988 --> 00:01:02.362 align:center line:-1 position:50% size:59% and you'll see, again, it appears to be randomly jumping to a more dominant level. 00:01:02.362 --> 00:01:05.232 align:center line:-1 position:50% size:40% This is evidence of arbitration. 00:01:05.232 --> 00:01:12.205 align:center line:-1 position:50% size:64% Multiple nodes are beginning to transmit frames at nearly the same time, 00:01:12.205 --> 00:01:15.809 align:center line:-1 position:50% size:53% and they have different levels of priority. 00:01:15.809 --> 00:01:18.979 align:center line:-1 position:50% size:63% Let's do some analysis on this particular frame. 00:01:18.979 --> 00:01:26.253 align:center line:-1 position:50% size:61% First of all, let's use Segmented Memory and just see how often does this frame occur. 00:01:26.253 --> 00:01:30.190 align:center line:-1 position:50% size:42% I'll go into the acquisition menu. 00:01:30.190 --> 00:01:32.459 align:center line:-1 position:50% size:45% Let's select "Segmented Memory," 00:01:32.459 --> 00:01:38.899 align:center line:-1 position:50% size:62% and let's capture 100 consecutive occurrences of this particular frame. 00:01:44.237 --> 00:01:48.809 align:center line:-1 position:50% size:44% There, you can see in the Lister, every acquisition that it captured 00:01:48.809 --> 00:01:52.980 align:center line:-1 position:50% size:53% was the message called "Brake torque." 00:01:52.980 --> 00:01:58.652 align:center line:-1 position:50% size:60% Over here, on the Segmented table, we can see how often this frame is occurring 00:01:58.652 --> 00:02:01.121 align:center line:-1 position:50% size:40% which is called the cycle time. 00:02:01.121 --> 00:02:05.959 align:center line:-1 position:50% size:57% We can see that it's occurring every 20 ns. 00:02:05.959 --> 00:02:14.434 align:center line:-1 position:50% size:56% In this case, we captured 100 consecutive occurrences for approximately 2 seconds. 00:02:14.434 --> 00:02:18.372 align:center line:-1 position:50% size:63% Let's turn off Segmented Memory, press "Run," 00:02:18.372 --> 00:02:24.144 align:center line:-1 position:50% size:46% and now, let's set up the scope to trigger not only on brake torque 00:02:24.144 --> 00:02:28.815 align:center line:-1 position:50% size:42% but trigger on brake torque only when arbitration occurs. 00:02:28.815 --> 00:02:38.258 align:center line:-1 position:50% size:48% For that, we can use "Zone Trigger." 00:02:38.258 --> 00:02:47.300 align:center line:-1 position:50% size:40% Now, it's only acquiring frames when arbitration occurs. 00:02:47.300 --> 00:02:55.675 align:center line:-1 position:50% size:61% Let's go back to Segmented Memory and let's capture 100 consecutive occurrences of this 00:02:55.675 --> 00:02:58.412 align:center line:-1 position:50% size:50% and see how often arbitration occurs. 00:03:02.482 --> 00:03:10.657 align:center line:-1 position:50% size:63% Here, we can see the first two segments, they were 20 ms apart, which is the cycle time. 00:03:10.657 --> 00:03:18.065 align:center line:-1 position:50% size:45% The second one was 80 ms later, then 20 ms, 80 ms, and so on. 00:03:18.065 --> 00:03:20.434 align:center line:-1 position:50% size:43% There's a repeating pattern here, 00:03:20.434 --> 00:03:25.005 align:center line:-1 position:50% size:56% and that's because I'm using an arbitrary waveform generator 00:03:25.005 --> 00:03:28.075 align:center line:-1 position:50% size:58% to produce this waveform, and it's repeating. 00:03:28.075 --> 00:03:33.380 align:center line:-1 position:50% size:41% In reality, if you're monitoring live traffic from an automobile, 00:03:33.380 --> 00:03:37.451 align:center line:-1 position:50% size:44% it's going to be relatively random. 00:03:37.451 --> 00:03:44.291 align:center line:-1 position:50% size:64% Let's now go back, turn off Segmented Memory, turn off Zone Trigger. 00:03:46.660 --> 00:03:51.398 align:center line:-1 position:50% size:47% Remember, when we capture multiple frames here consecutively, 00:03:51.398 --> 00:03:55.035 align:center line:-1 position:50% size:33% we can see occasionally the red hopping in here. 00:03:55.035 --> 00:03:59.272 align:center line:-1 position:50% size:59% These are errors that the scope is capturing. 00:03:59.272 --> 00:04:03.410 align:center line:-1 position:50% size:48% Let's uniquely trigger now on errors. 00:04:03.410 --> 00:04:10.217 align:center line:-1 position:50% size:38% I'll go into the Trigger menu, select "Trigger on all errors." 00:04:16.289 --> 00:04:20.694 align:center line:-1 position:50% size:54% Let's scale it to about 30 μs per division. 00:04:20.694 --> 00:04:23.663 align:center line:-1 position:50% size:45% Now, it's capturing multiple errors. 00:04:23.663 --> 00:04:32.806 align:center line:-1 position:50% size:70% Let's go into the Segmented Memory menu and let's capture 100 consecutive occurrences of errors. 00:04:34.174 --> 00:04:37.844 align:center line:-1 position:50% size:66% Here, you can see how often errors are occurring. 00:04:37.844 --> 00:04:41.715 align:center line:-1 position:50% size:47% Over here in the Lister you can see the different type of errors. 00:04:41.715 --> 00:04:48.121 align:center line:-1 position:50% size:54% This particular frame has a stuff-bit error. 00:04:48.121 --> 00:04:54.794 align:center line:-1 position:50% size:51% This particular frame has a CRC error and an acknowledge error. 00:04:54.794 --> 00:05:00.333 align:center line:-1 position:50% size:61% We could further filter down on specific errors, so let's do that. 00:05:00.333 --> 00:05:03.036 align:center line:-1 position:50% size:45% Let's turn off Segmented Memory. 00:05:03.036 --> 00:05:08.675 align:center line:-1 position:50% size:58% Go back into the Trigger menu, and then rather than triggering on all errors, 00:05:08.675 --> 00:05:13.380 align:center line:-1 position:50% size:58% let's trigger uniquely only on stuff-bit errors. 00:05:15.649 --> 00:05:18.952 align:center line:-1 position:50% size:47% Let me rescale the time base here. 00:05:26.293 --> 00:05:32.032 align:center line:-1 position:50% size:53% We'll go back into the acquisition menu, select "Segmented," 00:05:32.032 --> 00:05:41.474 align:center line:-1 position:50% size:62% and let's capture 100 consecutive occurrences of frames that have stuff-bit errors. 00:05:47.514 --> 00:05:53.753 align:center line:-1 position:50% size:42% Here, we can see stuff-bit errors are occurring every 100 ms. 00:05:53.753 --> 00:06:00.393 align:center line:-1 position:50% size:59% Again, we have a repeating pattern because it's from the arbitrary waveform generator. 00:06:00.393 --> 00:06:09.069 align:center line:-1 position:50% size:61% Stuff-bit errors occur only in a particular frame called transG or something like that. 00:06:10.337 --> 00:06:16.810 align:center line:-1 position:50% size:63% Here, you've been able to see how you can use Zone Trigger to uniquely trigger on arbitration 00:06:16.810 --> 00:06:23.383 align:center line:-1 position:50% size:56% as well as Segmented Memory to capture multiple occurrences of particular events 00:06:23.383 --> 00:06:25.752 align:center line:-1 position:50% size:29% over a long timespan.