handheld scopes - Page 1
Forum section: electronics / general

author: DazA1
author_rank: Contributor
timestamp: April 26, 2015, 10:40:26 am
content: Any chance of a video on handheld oscilloscopes for people doing on site testing?The fluke 190 series looks like the leader in this market and their "connect and view" feature seems useful (see video)https://youtu.be/UXhssDSmTS4I own a siglent SHS806 non isolated inputs 2 CH at 60MHz at the opposite end of the flukes price range. It has its flaws and little niggles but until i can justify the price of fluke it will do me fine.It would be interesting to see what Dave would make of it especially the safety of the isolated version.

author: TheNewLab
author_rank: Frequent Contributor
timestamp: April 29, 2015, 09:42:47 am
content: I like the idea of this.Hey, how about DazA1 doing a video how actual use of a handheld scope in the field!!

author: DazA1
author_rank: Contributor
timestamp: April 29, 2015, 09:17:50 pm
content: I was using it on a site last week looking at the output of a 3 phase motor inverter drive, i could have recorded that but it would also include some of the annoying short comings it has. (i was looking into reflected waves on the 400v pwm signal, found 1Kv pulses on the rising edges)Siglent seem very interested at first with my concerns and with the evidence i send them but it always seems to go quiet. I do receive regular emails from the sales department though.It would be really good if Dave could put it through its paces perhaps against the fluke to see how good it really is.Has anyone watched the video i linked to? Any opinions of Flukes "connect and view"?

author: jlmoon
author_rank: Unknown
timestamp: April 29, 2015, 09:29:42 pm
content: Quote from: DazA1 on April 29, 2015, 09:17:50 pm400V pwm inverter drive signals? Hope you had a HV diff probe for those test.

author: DazA1
author_rank: Contributor
timestamp: April 30, 2015, 07:21:48 pm
content: Not this time, i used a HV oscilloscope probe with 500:1 attenuation. Obviously the scope is battery powered and has no connection to earth and the BNC connectors are insulated.My next purchase will be an isolated scope but i cant justify that expense at the moment.

author: R_G_B_
author_rank: Frequent Contributor
timestamp: May 27, 2015, 08:50:12 pm
content: hysteresis triggering allows you to select a fresh hold to trigger on instead of just edge triggering if i'm corrected. The THS720p, THM565, fluke 125 and some others all do this if you're trying to trigger on complex pwm motor drive waveforms.R_G_B_

author: R_G_B_
author_rank: Frequent Contributor
timestamp: May 27, 2015, 09:00:39 pm
content: R_G_B_

author: DazA1
author_rank: Contributor
timestamp: May 30, 2015, 08:25:55 pm
content: The shaft voltage video was intersting but it would have been nice to see how much current was flowing as well. Thanks for posting the videos.My scope (Siglent SHS806) only has standard triggers Edge, Pulse, Video, Slope & Alternative. After watching Dave's video on Hold Off triggering i gave that a try, but no luck.Inverter PWM signals are difficult to view so i end up just stopping the scope and use the cursors.If anyone is intersted about voltage reflections on inverter motor drives then read this ABB technical paper.https://library.e.abb.com/public/fec1a7b62d273351c12571b60056a0fd/voltstress.pdf

author: Howardlong
author_rank: Super Contributor
timestamp: May 31, 2015, 07:50:16 am
content: Quote from: DazA1 on April 26, 2015, 10:40:26 amThe Owon HDS3102m-n does auto set dynamically too if you want it to, possibly other models do too. It works reasonably well, and works on both channels. You can also tell it whether to only auto set just the vertical (with trigger level) or just the horizontal (or both). Regarding the auto trigger level, even many old Tek CROs had auto level, but it doesn't seem to have found its way into many DSOs. It just looks for and sets the 50% input level.Being brought up on CROs, I don't use the dynamic auto features (except auto trigger level when available). I also hardly ever use the auto set button, other than for probe calibration. There's something about physically making the settings myself that actually makes interpreting the display easier somehow.