DSO  - digital scope  - buying Guide ??? - Page 1
Forum section: electronics / beginners

author: pilor001
author_rank: Contributor
timestamp: January 20, 2018, 01:18:20 pm
content: LOOKING FOR advices and experiences.....I wonder out of these which is the golden path...So not too "cheap" - low quality , but not too expensive (will not use ot for LAB or high precision works)I ve seen some brands like... - that have lower end scopes....HANTEKSIGLENTRIGOLVOLTCRAFT (Conrad branded a Hantek ??)Wolud be nice to find one that has a SIGNAL generator ambedded into the scope.One of the candidates ::::Hantek DSO4072C --sofrware limited to 70Mhz has a signal GEN , 2 CH , 1Gs/s - cheapest !!OrSiglent SDS1202X-E - has no GEN , 200Mhz , 2CH (more expensive)ORVOLTCRAFT (conrad selling) DSO-1084F - 80Mhz limited , 4ch , has a GEN - more expensive (looks like a HANTEK so copied)ORRIGOL DS1054Z -50Mhz 4CH , NO GEN.

author: lem_ix
author_rank: Regular Contributor
timestamp: January 20, 2018, 01:44:09 pm
content: Personally I'd take the Rigol for the 4 channels, Siglent being second choice and a bit better if you only need 2 channels. I wouldn't touch the Hantek stuff and Voltcraft is just a rebadge of some Hantek in this case. As for the generator a standalone is usually better, the scope ones are limited. Try to get a used one maybe?

author: BravoV
author_rank: Super Contributor
timestamp: January 20, 2018, 01:49:53 pm
content: Quote from: pilor001 on January 20, 2018, 01:18:20 pmState the budget limit, then all the talk and discussion will become more meaningful.

author: pilor001
author_rank: Contributor
timestamp: January 20, 2018, 01:55:22 pm
content: Well 2CH are "enough"....Will not use the scope too often , based on the past...on the other hand, having as many "toys" in the scope as possible... woluld be nice.Will not do high freq. stuff nor high precision work - so this is not a big thing. But a decent quality and support would be fine.BUDGET ::: 500 EUR

author: David Hess
author_rank: Super Contributor
timestamp: January 20, 2018, 10:38:31 pm
content: Quote from: pilor001 on January 20, 2018, 01:18:20 pmThis is an overrated feature unless the signal generator works in conjunction with the oscilloscope as a network analyser.

author: pilor001
author_rank: Contributor
timestamp: January 21, 2018, 05:57:20 pm
content: Basically now i wan to "tune" a DC servo motor and its controller and need some response analisys...So the motor's and controller's (close loop tuning) response (current monitoring) to the input (sq. wave is the best for it)

author: David Hess
author_rank: Super Contributor
timestamp: January 21, 2018, 08:42:12 pm
content: Quote from: pilor001 on January 21, 2018, 05:57:20 pmThat is just a lower frequency version of doing transient response analysis on a voltage regulator or other feedback system. A DSO will be ideal for this because of the relatively low frequencies involved but an analog oscilloscope could also be used.The signal source can be any square wave. I just use one of my ancient analog function generators because they allow easy adjustment but the built in function generator available on some DSOs can do it also. I would not pay a premium for this though.I have not used them so I do not know exactly how suitable they are but there are a couple of inexpensive USB based DSOs which support network analysis that might be ideal for this. They use their waveform generator in combination with the oscilloscope to generate bode plots. The Syscomp Design CircuitGear Mini CGM-101 linked below is only about $110.https://cleverscope.com/http://www.syscompdesign.com/Instruments_ep_42.html

author: pilor001
author_rank: Contributor
timestamp: January 21, 2018, 08:58:31 pm
content: My understaning is that....I have to have some kind a plotted diagram about the response to see whats up.So i want to see the rise / fall , and overshooting , oscillation dampening etc.... compared to the input (so dealys and so can be observed)

author: David Hess
author_rank: Super Contributor
timestamp: January 21, 2018, 09:28:09 pm
content: Quote from: pilor001 on January 21, 2018, 08:58:31 pmThat is the basic transient response test and is where I usually start. With some work, the overshoot and dampening can be used to figure out what is going on but I usually just adjust the frequency compensation for critical dampening and then reverse engineer what is going on with the unknown elements like the load.The two products I linked above can do that but can also automatically generate low frequency phase and amplitude plots versus frequency. Another way to do this involves a step response and FFT but I do not know of any inexpensive DSOs which support this even though it is trivial.

author: pilor001
author_rank: Contributor
timestamp: January 21, 2018, 10:10:31 pm
content: I donno why but our Servo'D machine (US made) had a newer controller (Also US made - AMC)... and there is no enough settings avialable.some Pots there.. well Input gain (from the logic contorller) for the REF signal ... yep analogue + - 10 V commands. 1 Pot for the LOOP gain (tacho - veloc gain), and a balance and a CURR limit.So now either they can (wan to) help to find a sollution (overshooting and making som swings) or ihave to rev. eng. the panel to find some D element changing spots.

author: rhb
author_rank: Super Contributor
timestamp: January 22, 2018, 03:42:52 am
content: You should look at this:https://www.eevblog.com/forum/blog/eevblog-1044-siglent's-$499-sds1104x-e-4ch-oscilloscope-teardown/msg1406548/#msg1406548Obviously no assurance that another one will be that good. I strongly suggest getting one of Leo's pulse generators to evaluate whatever you decide to buy. Just remember that you need to use a 50 ohm thru termination. A tee and 50 ohm terminator is what I used.

author: paulca
author_rank: Super Contributor
timestamp: January 22, 2018, 08:26:16 am
content: On a similar vein does anyone know of any of the mini-scopes which are functional and cheap? I mean a little handheld low bandwidth scope that either runs off a battery or DC jack and includes a screen?I've seen some dodgy looking ones and I've seen some expensive ones, but wondered if anyone can recommend one?My main scope effectively needs me to go and get the laptop from the bedroom and faff around setting it up, wasting bench space etc. So I tend to avoid probing things I probably should check quickly. I figured a handheld mini-scope would tell me a lot of things and if anything strikes me as odd I can investigate with the USB DSO.

author: CharlieEcho
author_rank: Regular Contributor
timestamp: January 22, 2018, 12:45:13 pm
content: How cheap?I periodically haunt eBay for used handheld TekScopes in good condition but I haven't made snagging one a priority, the working ones are still a bit too pricey even w/o probes & accessories, within range of the 2ch Micsig tablet. The 720A is 100 MHz & 2 channels. The display is kinda crude though, more like 90s graphing calculator than the current picoscope LCDs, so I guess it depends on the intended use (for me, appliance and automotive stuff, they're reasonably rugged and integrate a meter).If you're talking about the sub 100MHz stuff from generic vendors, I haven't a clue what's decent (if anything).Regarding affordable bench scopes generally, I've been agonizing over this lately and am probably going to go with the updated Siglent.

author: paulca
author_rank: Super Contributor
timestamp: January 22, 2018, 02:12:28 pm
content: I mean really cheap, 5, 10, 20Mhz.I bought one of these:https://hobbyking.com/en_us/dso112a-coral-mini-handheld-digital-oscilloscope.html?___store=en_usThough not from HobbyKing. £65.It's really for checking basic things like mosfet gate signal, button bounce, noise, changing voltages, logic signal levels. Nothing that really requires high bandwidth or high precision.Something to be in the of the bench toolkit that doesn't require I plug the laptop and USB DSO scope in. If I need to investigate something the mini-scope can't do I can of course go to the USB DSO which has a measly 20Mhz.

author: Terry01
author_rank: Frequent Contributor
timestamp: January 22, 2018, 02:14:02 pm
content: Check out the Mooshimeter Paul. I don't have 1 but I have seen them recommended on another forum I go on called Electronics Point. One of the guys has one and says they are great for exactly what your needing.