Oscilloscope Buying questions

[JPortici]

And my doesn't, which is why i'm considering that mine have problems.
Actually i think i always say 'my' or 'mine' and never talked about all the 1054 in existence

[rstofer]

There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?

MSO or DSO?  Which model?

That is a very cool feature.  I don't know that I need it but it is very interesting.  I know my little FPGA Logic Analyzer won't do anything like that.  I can have don't cares in a parallel word but not in a serial stream.  Nice!

[Fungus]

I wonder if i indeed have a faulty scope. I'll make further tests and eventually contact rigol

The thing to realize is that triggering isn't a software function. It's perfectly possible that an oscilloscope has a defective trigger.

[wraper]

There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?

MSO or DSO?  Which model?

That is a very cool feature.  I don't know that I need it but it is very interesting.  I know my little FPGA Logic Analyzer won't do anything like that.  I can have don't cares in a parallel word but not in a serial stream.  Nice!

There is no MSO model yet, bet seems will be in the future because there is a place for logic analyzer add-on board inside the scope.

[rstofer]

There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?

MSO or DSO?  Which model?

That is a very cool feature.  I don't know that I need it but it is very interesting.  I know my little FPGA Logic Analyzer won't do anything like that.  I can have don't cares in a parallel word but not in a serial stream.  Nice!

There is no MSO model yet, bet seems will be in the future because there is a place for logic analyzer add-on board inside the scope.

Which model should I research?  Is the cost in the same order of magnitude as the DS1054Z?

[JPortici]

I wonder if i indeed have a faulty scope. I'll make further tests and eventually contact rigol

The thing to realize is that triggering isn't a software function. It's perfectly possible that an oscilloscope has a defective trigger.

I have no idea about rigol but i think that (almost) any other mode than edge triggering might need a software side to analyze the data
but iight be wrong of course

[wraper]

Which model should I research?  Is the cost in the same order of magnitude as the DS1054Z?

Direct competitor with not hacked DS1054Z is GDS-1054B. It is overall much better scope but there are no decoding options to unlock, not hacked DS1054Z has no decoding either. http://www.tequipment.net/rigol/gw-instek-gds-1054b-vs-rigol-ds1054z/
Or you can go to more expensive GDS-2000E series, decoding already included out of the box, no need to hack.  http://www.tequipment.net/instek/oscilloscopes/series_gds-2000e-series/

[rstofer]

No, I was asking about the specific model that allowed long strings of "don't cares" in a serial decode.  I wasn't looking for a substitute to the DS1054Z.  It would be nice if the decode was free but I'm more interested in how much it costs to get the feature.  I doubt that I'll even NEED the feature but it would be worth knowing about.  Once I get the model number, I'll hunt down the User Manual.

[nctnico]

No, I was asking about the specific model that allowed long strings of "don't cares" in a serial decode.  I wasn't looking for a substitute to the DS1054Z.  It would be nice if the decode was free but I'm more interested in how much it costs to get the feature.  I doubt that I'll even NEED the feature but it would be worth knowing about.  Once I get the model number, I'll hunt down the User Manual.

That is the GDS2000E series:
http://www.gwinstek.com/en-global/products/Oscilloscopes/Digital_Storage_Oscilloscopes/GDS-2000E

[rstofer]

So, something like the GDS-2104E to get 100 MHz and 4 channels - $1200.
That's a little over the top for me and my little hobby.  Actually, the DS1054Z was a stretch since I already had a Tektronix 485.

Still, if that decoding feature is truly necessary in the commercial arena, $1200 isn't a lot of money.  Pretty nice!

Page 163 of the User Manual describes the 10 byte trigger setup.  It's also a neat feature to be able to trigger on the end of a message (CR, LF, etc), the start bit or even parity error although, in my limited experience, parity errors don't happen.  But I don't use long lines either.

For my purposes, I don't see any need to debug UART communications.  I can just jam the stream into a terminal.  But SPI and especially I2C decoding is much more problematic.  Any scope that will decode these streams will be a blessing.

For I2C, it is possible to use a couple of logic gates to find the START condition and use the output to trigger the scope.  Like this:
http://www.i2cchip.com/monitoring_i2c_bus.html  This isn't a complete solution but it's a start.

SPI is triggered off of SEL' so no problems there.

[wraper]

So, something like the GDS-2104E to get 100 MHz and 4 channels - $1200.
That's a little over the top for me and my little hobby.  Actually, the DS1054Z was a stretch since I already had a Tektronix 485.

Still, if that decoding feature is truly necessary in the commercial arena, $1200 isn't a lot of money.  Pretty nice!

Check 200 MHz GDS-2204E, it's actually cheaper than 100 MHz model because have bigger discount for some weird reason. Actually 100 MHz is more expensive than $1200, so likely you seen the price for 200 MHz model but read the model wrong.

[rstofer]

I could have gotten distracted on the price.  The first price I saw was $1700 (more or less) and when I saw $1200, I changed my reply.  You're right, it is odd that the 200 MHz version would cost less.  In fact, there would be no reason for a distributor to stock the 100 MHz version.  Unless the 200 MHz version lost a feature...

[Fungus]

For my purposes, I don't see any need to debug UART communications.  I can just jam the stream into a terminal.  But SPI and especially I2C decoding is much more problematic.  Any scope that will decode these streams will be a blessing.

If you're serious about serial decoding then a dedicated logic analyzer will always be better/cheaper than a general purpose oscilloscope.

Even if the 'scope has good decoding software the RAM will be limited, the screen will be cramped, and oscilloscope knobs and buttons are really the wrong user interface. A PC based logic analyser can record data for minutes at a time and a mouse/keyboard interface works much better.

Saleae devices are popular: https://www.saleae.com/

[nctnico]

I disagree. The reason you want to look at serial data is usually because you (have to) expect a problem with the signal at the electrical level as well. Just hooking up a logic analyser will get you banging your head against the wall sooner or later because it doesn't show the problems in the analogue domain. Besides that a good scope allows to save the decoded data to a CSV file so you can go through it with Excel (or similar) on a PC.

[Howardlong]

Have to say I'm with nctnico on this one, I hardly ever use a PC based logic analyser nowadays, although I did use them extensively back when I didn't have a scope with decoding capability.

Indeed, saving to CSV is one of the few reasons to ise a PC based LA, but that's not something I often find I need to do. My work tends to be in interactive debugging sessions rather than having any need to save a serial stream for later perusal.

PC based LAs don't often have the more complex triggering capabilities of a scope, and those such as the Saleae depend more on post processing. Also the sample rates of lower end LAs aren't enough for today's high speed serial busses.

Different strokes I guess, I know many prefer PC based LAs to scopes for this stuff.

[Fungus]

Have to say I'm with nctnico on this one, I hardly ever use a PC based logic analyser nowadays, although I did use them extensively back when I didn't have a scope with decoding capability.

Fair enough.

Just one more reason to prefer a DS1054Z over a GW-Instek if you're on a tight budget.

(free decoders!)

[rstofer]

I have never needed to debug a serial stream.  I may display a trace on an analog scope just to check the logic levels and maybe look at the SPI chip select, clock idle condition and maybe one data byte but that's about it.  ETA: It just works out that way.  Others will have varying experiences.

For microcontrollers, the best debug tool is 'printf()' (or equal).  Seriously!  The first thing I do with bare iron uC projects is get the UART running.  Then I add in some conversion functions from K&R (The C Programming Language) and I'm ready to go.  This is a great time to implement the first interrupt routine - just to see...

OTOH, for FPGA projects, I want to trace states.  Since I use one-hot encoding, this often involves ginning up new debug signals and routing them out to the board along with the clock.  This is fine on the older boards with 40 or 50 pin headers, not so good for PMO connectors. Several years ago it was suggested that I build a logic analyzer internal to my project and this is probably a great idea.  It is so good that I am using the Xilinx ILA IP.  I don't have much experience yet but it appears to be a very slick solution and, apparently, I can have multiple instances.  This allows me to watch the interaction from the CPU and over at the peripheral.  I predict this gadget will get more use than the rest of my equipment combined!

Sure, I want my scope to decode buses.  But for a very long time, like up until a couple of weeks ago, I didn't have that capability and my projects still got built.

[PartialDischarge]

Example of Rigol design and build "quality". RP-3300A probe at the BNC connector side.  Central conductor living by it's own in the hole and shorting to the metal. Already repaired both of those I received with DS-2072 by bending the wire. But they failed again, guess will need to fill the hole with silicone to prevent them shorting again. Also you can see quality construction with 2 resistors soldered on top of each other, one of them upside down. Hook attachments never worked properly too. When you press it, it's very scratchy, often gets stuck and the gook on the end is no good too, very hard to attach to the measuring point. Piece of crap in one word.

Just got my DS2072a today, and had a look at the probe, its been fixed. It also has a "TUVRheinland" sticker attached (which  I believe is some kind of german quality board?? ) although don't know why...

[Fungus]

Just got my DS2072a today, and had a look at the probe, its been fixed. It also has a "TUVRheinland" sticker attached (which  I believe is some kind of german quality board?? ) although don't know why...

Don't let the Pesky Facts get in the way of a good rant.

[wraper]

Just got my DS2072a today, and had a look at the probe, its been fixed. It also has a "TUVRheinland" sticker attached (which  I believe is some kind of german quality board?? ) although don't know why...

Don't let the Pesky Facts get in the way of a good rant.

Good for them that they fixed this. Though this still does not change the fact that Rigol made that kind of ridiculous crap on some point of time. Also it's only one of the "features" of these probes that pisses me off. Others are: attachable hooks are half-working crap because get stuck in pressed position (had read a lot of complaints about that). Hard to attach and does not hold well on the lead attached because of the shape of the hook itself. Rubber channel identification rings detach from the place multiple times a day. Probes are unnecessarily bulky at the BNC connector side, therefore hard to attach to the scope and obstruct attaching a second probe or accessing the scale knobs on the cramped DS2000 front panel (No such problem with GW Instek probes attached to the Rigol scope, LOL). And that's just because of rectangular plastic enclosure, probe is much smaller inside and has round shield. Why not put round enclosure  ? Probes are rubbery-bendy, therefore hard to precisely poke onto some tiny pads where it is easy to short something.

[PartialDischarge]

Recenty I got a Keysight probe (350Mhz). Has the same "box" as the rigol or even bigger. The tip came bent, no worries its a keysight so it must be fine that way. Besides its the cheapest looking thing I've ever seen, the rigols has a soft plastic and looks great .

I guess the discussion will continue for ever, but if so many "electronics-hobbyist-who-write-on-forums" had Keysights and Teks instead of Rigols you'd see LOTS of complaints about their quality and software bugs online.

[wraper]

Recenty I got a Keysight probe (350Mhz). Has the same "box" as the rigol or even bigger.

Do you have rigol probe to compare side by side? Because Rigol apparently is much bigger than Keysight probe. Especially that huge BNC connector with plastic molded on top of metal. EDIT, after examining photos of keysight probe, that box actually seems maybe a little bit bigger than my instek probe on the photo. Nothing like that Rigol box.

the rigols has a soft plastic and looks great .

That "soft" (i think probably rubber) is a piece of shit. It's not good at all when the probe bends in your hand. And it's too small too. Very uncomfortable to hold.

[Fungus]

Don't let the Pesky Facts get in the way of a good rant.

Good for them that they fixed this. Though this still does not change the fact that Rigol made that kind of ridiculous crap on some point of time.

You're missing the point, which is: Rigol aren't the only company making sub-standard stuff. Two weeks ago everybody here was worshipping "Keysight" and saying their stuff was incredible quality and sales support was anazing.

Now the forum is full of threads proving that wrong - Keysight 'scopes dying all over the place and Keysight support asking people for 90% of the price of a new 'scope to fix theirs.

Nobody's saying Rigol's perfect, but neither is anybody else.

(And at least Rigol stuff is cheap - you're not paying $2000 for the problems).

[wraper]

Don't let the Pesky Facts get in the way of a good rant.

Good for them that they fixed this. Though this still does not change the fact that Rigol made that kind of ridiculous crap on some point of time.

You're missing the point, which is: Rigol aren't the only company making sub-standard stuff. Two weeks ago everybody here was worshipping "Keysight" and saying their stuff was incredible quality and sales support was anazing.

Now the forum is full of threads proving that wrong - Keysight 'scopes dying all over the place and Keysight support asking people for 90% of the price of a new 'scope to fix theirs.

Nobody's saying Rigol's perfect, but neither is anybody else.

(And at least Rigol stuff is cheap - you're not paying $2000 for the problems).

Good luck getting that keysight scope for less than $5000 if you are located in Brazil. As of Rigol, even during the first weeks of warranty period I had very piss poor service from them. And this is in EU. In Brazil you already should be thankful that support exists as such.

Keysight support asking people for 90% of the price of a new 'scope to fix theirs.

In Brazil pricing, most likely it was below 40% of the new scope price.

[Fungus]

Good luck getting that keysight scope for less than $5000 if you are located in Brazil. As of Rigol, even during the first weeks of warranty period I had very piss poor service from them. And this is in EU. In Brazil you already should be thankful that support exists as such.

You think Spain is any better? 

(well, ok, at least we're European so I can order my stuff from Germany)