Why not use standard lab scopes?

A scope, meter, etc. that is ground or earth-referenced means the scope always makes its measurement with respect to that potential. A scope that is floating will make a measurement between between the 2 potentials that its leads are applied to. What is considered ground on the latter scenario is not always at the same potential as the earth-grounded one on the former. I hope that makes sense.

Any scope that is connected to a wall outlet- particularly ones that have the 3rd prong ground on their power plug- are candidates for being ground-referenced. Most, if not all, bench scopes that are powered in this fashion are indeed ground-referenced, as it is an important safety precaution for them to have.

Any scope that is running solely off batteries is, by its very nature, taking floating measurements and is not ground-referenced. That said, any battery powered scope that a user decides to plug into a wall outlet to charge its batteries can potentially TURN INTO a ground-referenced one. It is for this reason that it is always best let a scope run solely off its batteries when using it- at least in the automotive arena- since you want to see values between the 2 potentials present, not in comparison to earth ground. Another reason to let a scope run off its batteries is because the act of charging in itself has been known to introduce interference on some scopes (and not just the cheap ones) and thus distort readings.

When using ground-referenced scopes, one thing to always keep in mind is that the ground on your (garden variety, passive) probe/test lead is always directly bonded to earth. This means wherever you decide to hook that ground up to in a circuit will have earth potential applied to it as well. If you don't connect it to a point that is at or near that potential, bad things can happen, especially if enough energy is present. Imaging sticking a wire between the ground and hot terminals in a wall outlet and you see what I mean.

There are ways to turn a ground-referenced scope into one that takes floating measurements, which can help remove some of the problems inherent with them. Perhaps the most dangerous way is to simply break the ground prong off the plug and run the scope like that. Safer ways to do it include adding an isolated transformer between the the mains and the scope, using a differential probe instead of the passive probes, or taking 2 separate readings with the scope then using the math function to display a compensated value/wave form.

To make matters more complicated, some scopes (more expensive ones, usually) have what's called isolated grounds in regards to their BNC inputs. This means the ground on each channel's BNC is isolated from the next and they aren't just simply daisy-chained together. If you took an ohm meter and checked for continuity between each channel's BNC ground, on a scope that had isolated grounds, you wouldn't hear any beeping.

Though I'm not 100% sure, I believe having a scope with isolated inputs/grounds becomes important when during multi-channel analysis where the signal going in each BNC does not share the same ground. Though I'm far from an expert, I don't think it's really of the utmost importance to have a scope that includes that feature for automotive. More advanced diagnostics might make that a different story, however.

I haven't used either of the scopes you mentioned, but I know Pico does well because of its ease of use, especially in the area of software. You certainly pay for that feature, however. There are other USB scopes out there that do a commendable job for much less money but they usually require some extra knowledge on the user side of things. I'm reminded of my physics teacher who used, to me, what looked little more than a basic calculator to solve these crazy-ass equations the rest of us needed our high powered Ti-83's to do. He got the same answers we did, but did need to do a little more finagling to get there. I think the same is true for (most) lower-end scopes offered these days. If you're interested in learning and doing a little more of the legwork- especially if you aren't doing this stuff for a living- I don't think having a Pico is a necessity.
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@KSAT22 ,,, This is the point where I'm at. I am not a professional, that requires a PICO Scope. I have nothing against them,, I can't justify spending almost 2,000 for a 4 channel scope that only comes with test leads,, still need amp clamps , pickups , etc. I know your paying for the software and support,, but for someone like me,, in this new covid world we live in now,, can't be done..

I was close in buying their 2 channel bnc plus basic Pico model,,, but 2 channel scopes seem to be fading out for automotive use,,,evennthough on Pico's website that their 2 channel scope is delayed all the way into the late spring, their must be some demand for them.

My concept was using their advanced software PICO Automotive 7 software ,to overlay function. I know it is not as simple and requires more work to get what your looking for. so for example if you needed to have a crank case sensor waveform with the 2 cam shaft sensors,, do it in 2 steps "crank case sensor & cam sensor 1" than reading of the " crankcase sensor and the cam sensor 2" than over lay them in their software. Anyones' take on that concept,, can that be done on their new software? Kind of a 4 channel scope in a 2 channel concept.This is for personal use, so it is not a everyday needed item, at least to not need a 4 ch scope.

I will say ,, "my opinion,, with their new BNC Plus connection,, I wonder how that's going to hold up,, regarding dust, oil, grease debris, etc getting on those copper connections over time,, Wish they still made the older model,, simple design.

I am attaching 2 videos I found on you tube from a creator name Mechanic Mindset. He really helps a person like and others me who understands that a scope is required on todays vehicles,, but in a more affordable fashion.. Even if you follow the 2 attached videos,,,the scope is $300,, so if you do blow it up while learning the scope procedures,,, I won't have a breakdown.

I respect everybodys 'opinion on here,, so if anyone has the time , please watch the 3 video links I attached , and give me your thoughts. I'm aware that the other cheaper Pico Scopes are not able to be used on Pico's automotive software,, but as the impression from all the reading I do on this site

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>>>> " A SCOPE IS BETTER THAN NO SCOPE"...lol

Regarding the Autel,,,,, between watching the videos , reviews,, I noticed that the software is very erratic. I downloaded it from their site months ago,,, and even when you select the voltage for a particular channel,, it doesn't seem to take the first time, or it multiplies the voltage by double on the left side of their software interface,, on the pico software it obviously does not do that when I downloaded theirs as well..

I really like the Mic-Sig ATO1104...for a beginner,,, reviews are 50 / 50 across the board on that, but overall it seems somewhat decent. Posting that review as well. With some good test leads from AES Wave,, for someone who just needs a waveform ,,, is where I might be headed,, plus I don't need a laptop setup, which is hindering., especially for me I do all of my work outside in harsh weather environments.

This post is not against Pico in any regards,, it is more about the budget in these new times we all live in.

Anyone that has any input on other brands of the more reachable scope like Hantek, Mic-Sig, or the cheaper non automotive scopes,, please feel free to comment ,, good or bad......

If I remember correctly , the cheaper scopes like the non automotive Pico have a voltage input limit of 20 volts,, so I guess a attenuator would be used quite often to protect it.

Thanks for reading this long post.

Tried posting links,, seems not to take on here...sorry

If interested go to youtube: Awesome channels to watch on this siubject for low budget scopes that get the job done for non professional mechanics.

Channel ! - Mechanic Mindest

Channel 2- Atom's Workshop

look forward on anyones' comments


Don

the autel scope software is way behind the pico software. i tried out the autel, and if you can swing the pico i think you would be way ahead. you would never have to or wish you had, if you go pico. the software is that much better.. have you thought about something like a snap on vantage pro or other snap on platform? the built in information is what pushed me to buy a vantage pro. knowing how to connect for a test and what to expect is very useful, and having the meter settings set for you really help when starting out.

@ CHRIS85;;;;

It's funny you mentioned that about the snap on platform. Before Covid , I bought the new Bosch ADS625 scan tool at a discounted price, basing it on what was suppose to be the up and coming Diagnostic tool,, Happy I have it,, but ,it lacks many features. Bosch is way behind from what other brands have to offer, recently, Even the cheaper ThinkDiag units have the topography like the witech2 at Chrysler / Jeep/ Ram/etc. Bosch has great customer service,, reliable product.. but they need to update their interface on their software end. When I bought mine,, at the time,, Bosch was going to have a optional 2 or 4 channel add on unit ,,for the ADS series,,, it never happened.

Wished I waited and had saved up for a snap on back thenr at least a unit with a built in 4 channel scope. I was on ebay looking at exactly what you pointed out, but used,. they seem to hold their value,,, $$$,,,lol

I am a big fan of Scanner Danner's videos , I watch him with his scan tools,, very capable,,, gets the job done. having a scan tool with everything in one including a scope and a multimeter, is very nice.

The best I can swing with Pico is their automotive 2 channel unit. Time will tell,,,,, a lot of stuff is on back order due to chip shortages.

Thanks for your input on the Autel Scope,, not surprised by your findings. When I just downloaded their software with out buying their unit,, I noticed the software interface is very outdated and has many bugs in it.

Don

Regardless of the number of channels, a USB scope will probably give you the best bang for your buck, compared to stand-alone units whether from Snap-on/Micsig/etc. If you paired a decent 4 channel USB with a cheap Android device of your choice and added the paid version of HScope, there wouldn't be much you couldn't do compared to the big players. As far as performance goes- such as bandwidth, sampling rate and buffer size- you'd be way ahead of the game. Consider also, HScope software is updated/improved often and has a large support base, forum, etc.

Input voltage limitations with USBs aren't the end of the world, as long as you know what the expected voltage should be where you're probing. Attenuators are dirt cheap (Hantek ones, anyway) and most software apps will do the voltage conversion for you as long as you tell it what you're using. Input voltages that may go over the scope's spec (within reason, at least) don't usually mean it will make the thing smoke, as many have over-voltage protection starting at some magnitude higher. A cheap "Loto" brand scope I've been looking at, for example, has a paltry input limit of 5V, but it has overvoltage protection at some 60V. While that probably doesn't mean you can hook it up to line voltage directly, it does give you some leeway. Upping the budget just a few bucks on a USB usually gains you higher input values. For about $50 more than the Loto, the Owon VDS1022I is rated to handle up to 400V.

All that said, working in harsh environments obviously presents some problems with USB setup. I guess you could add an enclosure to the USB box and pair it with a rugged tablet or something, but that increases cost. Also, if you really wanted the scope to be in 1 single unit, you certainly would have to get creative. On that topic, I wouldn't be all that surprised if the Micsig actually is more or less a just a realization of that concept: a USB scope + Android tablet enclosed in 1 unit packaged with their own scope software. Not much different than what I hear Launch does, really.

When I posted the question I assumed all scopes could be run from a battery but I was clearly wrong. I believe there is a Rhode&Schwarz one that does and maybe a keysight. The R&S is definitely too expensive for comfort though. I got a hantek scope meter last year but have not yet had any need for the scope function on it.

Most Owon bench top lab scopes such as the SDS series have a battery pack option but although very capable scopes they are older designs that tend to eat battery charge and batteries tend to loose charge capacity over time the battery packs aren't cheap either although there is now a cheaper work around using standard cells


For a USB scope linked to a PC as already mentioned the OWON VDS1022i is a really great scope for very little money with decent software on both Windows and Linux