Siglent SDS804/814X HD or Rigol HDO914S for Mechatronics student

[eTobey]

All your problems are self made.

Then why did my problems make it onto the bug list? With some of my self made problems, i still made a greater contribution in count of issues, than all of you together (at times). You seriously have some issues of denying facts.

Fanboys...

[KungFuJosh]

All your problems are self made.

Then why did my problems make it onto the bug list? With some of my self made problems, i still made a greater contribution in count of issues, than all of you together (at times). You seriously have some issues of denying facts.

Fanboys...

You're rude and delusional. You didn't discover anything that hadn't already been discovered.

[2N3055]

All your problems are self made.

Then why did my problems make it onto the bug list? With some of my self made problems, i still made a greater contribution in count of issues, than all of you together (at times). You seriously have some issues of denying facts.

Fanboys...

It is very ironic that all the time you have signatures under your posts that directly apply to how people feel after having any kind of contact with you:

"Sometimes, after talking with a person, you want to pet a dog, wave at a monkey, and take off your hat to an elephant." (Maxim Gorki)

Like I said all your problems are self made.  I was not talking about bugs. But understanding the difference would mean reading without aggressive paranoid stance that everybody out there is out to get you. And general attitude that you are smarter and better than absolutely everybody else.

My advice to you would be to sell SDS800xHD. It is not a good scope for you. It will never be what you "expect it to be" because scope you would like to have either does not exist or you cannot afford it. And with platform getting increasingly bug free with every FW update, you will be denied the pleasure to create drama and throwing tantrums demanding "damn thing needs to fixed right away, because king is not happpy!".
Thinking about it, you should go back and buy DHO800 again. Just few days ago they discovered another bug that bricks the scope completely in newest FW that was published. Imagine "oh the glory!!" how fabulous would have been that it was YOU that discovered that!!
Oh how many diatribes and rude expletives you could have had then!

Compared to that, SDS800xHD is boring. It simply works, and minor thing here and there is not enough material for an episode of reality show.  Really, not a scope for you.

Hope you don't get this in a wrong way. Have a nice day.

[ebastler]

You're rude and delusional. You didn't discover anything that hadn't already been discovered.

That is clearly incorrect. I don't get it why we cannot find a common denominator here?

Yes, many of eTobey's findings were (and are) not described in sufficient detail; sometimes others had to help and pin down the boundary conditions for a bug. Yes, I also think there were too many, too early, too loud cries of "bug alert!!!". But yes, several annoying bugs were identified by eTobey, were pinned down, and the majority of them were fixed by Siglent in the meantime.

[KungFuJosh]

That is clearly incorrect. I don't get it why we cannot find a common denominator here?

Perhaps you're right. You've paid a lot more attention to those threads. What I saw was generally unpleasant. 🤷

[Jack359]

Hello, I just wanted to update you that I found locally mildly used Rigol DHO804 for a bit more than half the price of what it would have cost me Siglent SDS804X HD, so I leaped and bought it. It has firmware 00.01.02 and from what I read perhaps is better to use it as it is and update it only if I have issues.
I just noticed that in my dorm the power sockets are a bit weird (not Schuko) and if connect the scope it is not grounded. 
I watched the recommended here video about how not to blow up my oscilloscope

In it is mentioned that not grounding the oscilloscope is actually workaround if I want to measure grounded circuits but it is not recommended. Didn't get why..
I read that DHO804 is made to run of power bank as well, so I guess it is safe to use it not grounded ?

[Antonio90]

There might be a ground cable in the power sockets, not connected, left there by the installer. You could buy a grounded socket and get someone who knows what he's doing to install it for you.

My lab's room had also non-grounded power sockets and I just swapped them all with the breaker off. Without proper grounding, the chassis, the ground in the probe compensation connector, the BNC connectors and the ground clip of your probes can become live and kill you.

Some knowledgeable people float their 'scopes, but even experienced engineers have been killed by doing that. Call an electrician, run an extender cord from another room or whatever (not ideal), but ground your oscilloscope.

[Jack359]

There might be a ground cable in the power sockets, not connected, left there by the installer. You could buy a grounded socket and get someone who knows what he's doing to install it for you.

My lab's room had also non-grounded power sockets and I just swapped them all with the breaker off. Without proper grounding, the chassis, the ground in the probe compensation connector, the BNC connectors and the ground clip of your probes can become live and kill you.

Some knowledgeable people float their 'scopes, but even experienced engineers have been killed by doing that. Call an electrician, run an extender cord from another room or whatever (not ideal), but ground your oscilloscope.

Thanks. Some of the power sockets have ground hole and wire but they are a bit different than the plug and ground connection is not possible. I will try to find socket convertor or will just replace one of the sockets.

[Antonio90]

There might be a ground cable in the power sockets, not connected, left there by the installer. You could buy a grounded socket and get someone who knows what he's doing to install it for you.

My lab's room had also non-grounded power sockets and I just swapped them all with the breaker off. Without proper grounding, the chassis, the ground in the probe compensation connector, the BNC connectors and the ground clip of your probes can become live and kill you.

Some knowledgeable people float their 'scopes, but even experienced engineers have been killed by doing that. Call an electrician, run an extender cord from another room or whatever (not ideal), but ground your oscilloscope.

Thanks. Some of the power sockets have ground hole and wire but they are a bit different than the plug and ground connection is not possible. I will try to find socket convertor or will just replace one of the sockets.

If you can make a reliable ground connection, the DHO has a ground female plug in the back. That might get you by while you set everything up, but check the connection is solid and low impedance.

[2N3055]

Hello, I just wanted to update you that I found locally mildly used Rigol DHO804 for a bit more than half the price of what it would have cost me Siglent SDS804X HD, so I leaped and bought it. It has firmware 00.01.02 and from what I read perhaps is better to use it as it is and update it only if I have issues.
I just noticed that in my dorm the power sockets are a bit weird (not Schuko) and if connect the scope it is not grounded. 
I watched the recommended here video about how not to blow up my oscilloscope
In it is mentioned that not grounding the oscilloscope is actually workaround if I want to measure grounded circuits but it is not recommended. Didn't get why..
I read that DHO804 is made to run of power bank as well, so I guess it is safe to use it not grounded ?

Congratulations on a good money deal. Just make sure to not update to latest version of FW before Rigol publishes officially fixed one, not to brick a scope. Hope it will be OK for your use.

[Antonio90]

In it is mentioned that not grounding the oscilloscope is actually workaround if I want to measure grounded circuits but it is not recommended. Didn't get why..
I read that DHO804 is made to run of power bank as well, so I guess it is safe to use it not grounded ?

As per why it is not recommended, as the video explains, if you probe a mains ground-referenced circuit, the probe ground has to be connected to the circuit ground. If you clip your probe on, say, 220V, it will be shorted to ground with very low impedance. That will blow either the circuit, the probe, the oscilloscope or all of them.

On the other hand, if you do that with a floating oscilloscope, the grounding on the probe, the bnc inputs, chassis, etc, will all be at 220V potential with respect to ground, and you might very well be the path of least resistance to earth ground.

Floating the scope allows you to make a differential measurement (only one, all the BNC grounds are at the same potential), as opposed to single-ended with respect to earth ground. I don't think it is worth it, but to each its own. If you find yourself needing that often, look for a differential probe, either used or Micsig.

[Jack359]

On the other hand, if you do that with a floating oscilloscope, the grounding on the probe, the bnc inputs, chassis, etc, will all be at 220V potential with respect to ground, and you might very well be the path of least resistance to earth ground.

I'm wondering if the power adapter of the DHO804 has a fuse and can prevent short to the ground when used as floating scope ?

[Antonio90]

On the other hand, if you do that with a floating oscilloscope, the grounding on the probe, the bnc inputs, chassis, etc, will all be at 220V potential with respect to ground, and you might very well be the path of least resistance to earth ground.

I'm wondering if the power adapter of the DHO804 has a fuse and can prevent short to the ground when used as floating scope ?

Hello, no, ground connections are not fused. The fuse could silently fail, or break due to mechanical shock, manufacturing defect or whatever, and you would be left with floating device without knowing it.
EDIT: also, when floating, the problem is not shorting to ground, but dangerous voltages on the probes, connectors and outer case. The danger in that case isn't so much for the scope as it is for you touching the oscilloscope or the probes.

[Jack359]

Hello, no, ground connections are not fused. The fuse could silently fail, or break due to mechanical shock, manufacturing defect or whatever, and you would be left with floating device without knowing it.
EDIT: also, when floating, the problem is not shorting to ground, but dangerous voltages on the probes, connectors and outer case. The danger in that case isn't so much for the scope as it is for you touching the oscilloscope or the probes.

Doesn't it make any difference that the oscilloscope is  powered by USB-C and AC/DC power adapter rated to max 20V/3A which is connected to the power socket? Is it still as potentially deadly when floating?
I will not use it to measure my mains or circuits with 220V in them.

[Antonio90]

The dangerous voltages come from outside the oscilloscope, DSOs which connect directly to mains have a similar PSU on the inside.
If you only work with low voltages and isolated circuits, maybe, but really, just ground your oscilloscope.
You will have time later on to float it perfectly knowing that you should not do it in most cases.

[Jack359]

The dangerous voltages come from outside the oscilloscope, DSOs which connect directly to mains have a similar PSU on the inside.
If you only work with low voltages and isolated circuits, maybe, but really, just ground your oscilloscope.
You will have time later on to float it perfectly knowing that you should not do it in most cases.

  Last question - if I buy suitable powerbank then as far as I understand operating this scope won't be much different than tablet scope like this one https://www.micsig.com/product5/?
I know that it has less memory and miss some other not important things for me.
As I read the micsig also uses common ground and doesn't have isolated channels. 

[tautech]

Is it still as potentially deadly when floating?

You said in the OP:

I'm starting my Bachelor in Mechatronics so I would like to have a nice private oscilloscope.

At this point your knowledge is much lacking.

The industry now severely frowns on floating scopes and Differential probes have especially been developed to remove the need to engage in this dangerous practise.

Okay so you brought your first scope, but think of that like buying a car with a tow hitch, it will get you where you need to go but additional expenditure is required to make full use of it.

The world of Differential and Current probes awaits you.

[Antonio90]

Micsig has a grounding plug too, which should be connected for general purpose bench use. It can be floated easily and can be battery operated. There are also quite a few handhelds which are naturally floating, but also designed to work like that.

However, I can't really tell you it is fine to float your bench scope. It's a liability and an accident waiting to happen for a beginner. You'll probably have better judgement than me on this regard when you complete your degree, but right now, I really advise you to ground your new scope.

[Fungus]

In it is mentioned that not grounding the oscilloscope is actually workaround if I want to measure grounded circuits but it is not recommended. Didn't get why..

Because there's exposed metal on the 'scope (eg. BNC connectors) that are directly connected to the probe. Connect your the probe to a live wire? Those BNC connectors are now live.

The 'scope will be OK with that, the danger is to you if you touch them.

Grounding the 'scope avoids that. There's no way the BNC connectors can kill you if they're grounded. You can still kill yourself in other ways but the BNCs are safe to touch.

Micsig has a grounding plug too, which should be connected for general purpose bench use.

Or... just don't poke at mains electricity with it.

There's no need.

[Antonio90]

In it is mentioned that not grounding the oscilloscope is actually workaround if I want to measure grounded circuits but it is not recommended. Didn't get why..

Because there's exposed metal on the 'scope (eg. BNC connectors) that are directly connected to the probe. Connect your the probe to a live wire? Those BNC connectors are now live.

The 'scope will be OK with that, the danger is to you if you touch them.

Grounding the 'scope avoids that. There's no way the BNC connectors can kill you if they're grounded. You can still kill yourself in other ways but the BNCs are safe to touch.

Micsig has a grounding plug too, which should be connected for general purpose bench use.

Or... just don't poke at mains electricity with it.

There's no need.

Sure, there won't be dangerous voltages on the scope if you don't probe dangerous voltages. I'm just not so sure it is prudent to asume a newbie will never probe any dangerous voltage, even if that's not the intended initial use.
I talk from experience. Even though the plan is to stick with op-amps, a few transistors, a motor from time to time and small radio stuff, you will inevitably find something for "parts or repair" for free or too good of a price to let it pass, and start trying to repair it. Often without an isolation transformer. Maybe not, and old Tek and HP stuff is not available, expensive, or plainly uninteresting for the OP.
I stick with what I said, until he has his own criteria and doesn't need to ask.

But yeah, a 5V arduino board with 12V relays and a few sensors is not deadly, grounded scope or not.

[Fungus]

... start trying to repair it. Often without an isolation transformer.

Isolation transformers can be dangerous, too. They garantee your house circuit breakers will never trip. 

The thing newbies don't get is that grounding isn't done for the 'scope, it's done for the user.

The 'scope doesn't care if it's grounded or not.

[ptluis]

... start trying to repair it. Often without an isolation transformer.

Isolation transformers can be dangerous, too. They garantee your house circuit breakers will never trip. 

Specially when the internal insulation fails and the primary and secondary windings touch or there's a leak from primary into the chassis of the device 

[Jack359]

Yes, it became clear to me. Thanks.

If I ground the scope and poke high voltage stuff with it, I can destroy the scope.
If I don't ground it, I can kill myself cause then the BNC connectors and perhaps the case become live. There are electrically insulating gloves but they are not comfortable or very cheap.
The only safe way to do it is with differential probes and grounded scope.

[Fungus]

If I ground the scope and poke high voltage stuff with it, I can destroy the scope.

Hopefully only melt the probe wire.