Fast Scroll through 5 second capture? - Page 1
Forum section: electronics / testgear

author: rcbuck
author_rank: Frequent Contributor
timestamp: September 03, 2020, 11:38:13 pm
content: I have my new SDS2202X-E scope and have been playing with it. Everything works fine and it is really impressive for the money spent.I have a question that maybe someone can help me with. I have my AWG set to generate a 60 kHz sine wave. I set the scope up for 500 ms per horizontal division. This will give me 7 seconds of capture in Single mode. I press the Single button and I see Arm go active. Shortly after that I see Trig'd go active and 7 seconds later the Run/Stop button turns red and the captured data is on the screen.I then change the scope to 10 usec per horizontal division so I can see a nice clean 60 kHz sine wave on the screen.About 2 seconds after I saw Trig'd go active, I toggled the sine wave on my AWG by 180 degrees.What is the fastest way to scroll back through the displayed sine wave to find the sine wave reversal event at around the 2 second point? Scrolling with the horizontal division set to 10 usec will take a loooong time.If I press the Horizontal button to expand the wave form in the lower half of the screen, scrolling still follows the slow 10 usec setting.I played with the Runt trigger mode to try to get the scope to trigger on the phase change but was unsuccessful with that operation.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2020, 01:13:19 am
content: Using the Navigate buttons for a manual search.However the Search feature should find it too with an Interval setting and an appropriate trigger level.

author: Electro Fan
author_rank: Super Contributor
timestamp: September 04, 2020, 02:45:32 am
content: a video demo of X-E and also X plus showing search and navigate and maybe the runt trigger would be interesting

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2020, 02:49:33 am
content: Quote from: Electro Fan on September 04, 2020, 02:45:32 amSearch is quite straight forward to use if you apply the matter between ears to it.Little play with it here:https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1370717/#msg1370717

author: rcbuck
author_rank: Frequent Contributor
timestamp: September 04, 2020, 03:44:43 am
content: The Navigate function seems to work at same speed as Horizontal position knob.In the link photo 5 show a THRESHOLDS display. I don't see that on my scope. It appears in the link that the scope is in the RUN mode.I have a 5 second capture that I want to find a single phase reversal that is somewhere in that 5 second capture,The matter between my ears doesn't seem to be working very well.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2020, 04:00:01 am
content: Quote from: rcbuck on September 04, 2020, 03:44:43 amThought you can double tap it for faster speeds or press and hold......been a while since I played with it.QuoteIIRC you are right, it was in RUN. Thresholds only apply to some Search parameters, not all.QuoteWill have a play later with a long capture to solve your problem. Search should do it but you need use the right parameter and trigger level and maybe send settings to the Trigger.Once set up properly it works like a charm.Or as a last resort save the capture as a CSV and work on it with a PC.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2020, 07:48:33 am
content: Had a good fiddle for you rcbuck as it's not as easy as one would first imagine primarily because where a 180ophase change will appear on the sine wave is unpredictable.To prove this we must first catch it and at best we have a 50/50 chance based mainly on trigger level settings which seemed best high or low rather than middle.I Single Shot caught the phase change a couple of times in a few tries with a Dropout 'Over Time' trigger which seemed the most reliable however it may have been dumb luck.Anyways, now with a capture albeit in the middle of the display we can then use Search settings that return just this one event.A selection of screenshots attached with various menus and settings visible that should give you some ideas what to try next.

author: Andreas
author_rank: Super Contributor
timestamp: September 04, 2020, 05:17:03 pm
content: Quote from: rcbuck on September 03, 2020, 11:38:13 pmcan you use a math function with a low pass filter e.g. 10-20kHz?There should be a short amplitude change at the point with the phase reversal.with best regardsAndreas

author: rcbuck
author_rank: Frequent Contributor
timestamp: September 04, 2020, 05:32:08 pm
content: tautech, I had some luck. Not sure exactly how it works but the scope triggers when the phase change occurs. Screenshot attached.I am using a SDG2042X AWG and it appears to trigger at zero crossing each time. I am building a custom piece of hardware to generate the sine wave that will perform a 180 degree phase change every 2 seconds. With that hardware maybe I can come up with settings to capture 7 seconds of data and see 2 or 3 phase changes.Thanks for your help.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2020, 05:40:26 pm
content: Cool, getting there.A little disturbing thing you may have noticed and you can see it on my screenshots is now the Search flag is mostly obscured when in falls on the 0s trigger point, the blue pointer. You can just notice the tip of the white Search flag if you look hard enough. Might drop Siglent a note to try and improve the visibility of Search flags for occasions such as these.BTW, just noticed you have AC coupling set for channel and trigger. Use DC coupling unless expressly needing AC.

author: rcbuck
author_rank: Frequent Contributor
timestamp: September 04, 2020, 05:46:22 pm
content: Better screenshot attached. This is after change to DC coupling.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2020, 05:50:11 pm
content: Quote from: rcbuck on September 04, 2020, 05:46:22 pmTrigger too !Now you just need to adjust Search settings to flag just 1 event.