Holdoff does not work Siglent SDS814X HD - Page 1
Forum section: electronics / beginners

author: eTobey
author_rank: Super Contributor
timestamp: March 29, 2024, 10:47:16 am
content: Hi,i can not achieve a stable trigger with the holdoff time. I followed the manual, but it still wont work.What do i wrong? The trigger is jumping all over the place.Edit:A restart did not help.Interestingly, after trying to achieve the same with pulse trigger mode. The edge trigger worked afterwards.Edit 2:Found out, that, while moving the trigger level, the holdoff works!

author: ebastler
author_rank: Super Contributor
timestamp: March 29, 2024, 01:50:57 pm
content: Hmm -- this is baffling. Trigger Holdoff does indeed not work for me either, reproducibly, under pretty simple conditions. Please see the attached screenshot.Test signal has 100 µs bursts of a 100 kHz sine-wave, at 1 ms intervals, coming from an SDG2042. I have set the holdoff time to 200 µs -- longer than the burst duration, shorter than the interval, which should get stable edge triggering at the first edge of each burst. Shown in the screenshot with 1 second persistence time to make some of the false triggers visible.The scope does seem to respect the holdoff time as it should: When I measure the waveform update rate via Trigger-Out and an external counter, it drops as I increase the holdoff time. At very long holdoff times (say 200 ms), the frame rate drops to where you would expect it to be (5 Hz). But I can't get stable triggering. What am I overlooking?!

author: eTobey
author_rank: Super Contributor
timestamp: March 29, 2024, 02:12:20 pm
content: Are we both doing something wrong?Have you loaded my setupfile?I would not think, that a A$ 880 scope would have such an issue.

author: ebastler
author_rank: Super Contributor
timestamp: March 29, 2024, 05:27:57 pm
content: I did not use your setup; started from the Default settings to get a clean start.My setup.xml is attached.Edit: Replaced the setup.xml with a revised version. I had played with the settings in the meantime, so the stored settings included Auto triggering. Set back to Normal now, for consistency with the screenshots above. Auto vs. Normal does not make a difference in trigger stability here.

author: rf-loop
author_rank: Super Contributor
timestamp: March 31, 2024, 08:57:18 am
content: Quote from: ebastler on March 29, 2024, 05:27:57 pmI can confirm this bug.SDS824X HD, FW 1.1.3.3Started from factory defaults,100kHz sine, 600mVpp, 10 cycle bursts, 1ms burst period. Scope set after default: t/div 200us/div (and Ch1 100mV/div) Trigger (Rising Edge) Holdoff time 200usResult: Trigger holdoff fails.Same with several different signals and setups - fails.Simultaneously made all same tests with SDS3104X HD and all works just perfectly rock solid.Now only started stopwatch for measure time how long it takes before it is fixed (Siglent know it).

author: 2N3055
author_rank: Super Contributor
timestamp: March 31, 2024, 11:13:29 am
content: Quote from: rf-loop on March 31, 2024, 08:57:18 amI confirm too. Also confirm it is 800 specific.

author: BillyO
author_rank: Super Contributor
timestamp: April 01, 2024, 12:14:48 am
content: Does Siglent monitor this sub-forum?It maybe a good idea to start a thread or add this to a thread over on the TE sub-forum.

author: eTobey
author_rank: Super Contributor
timestamp: April 01, 2024, 05:21:46 am
content: Quote from: BillyO on April 01, 2024, 12:14:48 amI already did, but the fanboys didnt like that.

author: BillyO
author_rank: Super Contributor
timestamp: April 01, 2024, 01:39:36 pm
content: Quote from: eTobey on April 01, 2024, 05:21:46 amWell you have agreement from a couple of the more respected folks in the TE section. I'll send a PM to tautech to let him know about this thread.

author: ebastler
author_rank: Super Contributor
timestamp: April 01, 2024, 01:54:21 pm
content: There's already a link back to this thread from the main SDS800X HD bug/feature thread. So I think we are in good shape, and I trust that tautech has seen this too. He should be aware of this glitch since he is quite fond of using and recommending trigger holdoff!

author: 2N3055
author_rank: Super Contributor
timestamp: April 01, 2024, 02:43:30 pm
content: Quote from: ebastler on April 01, 2024, 01:54:21 pmIt was reported to Siglent allready..