Though I don't have time to get into this further at this point, hopefully the following observations can help folks who are considering purchasing these beautifully engineered instruments. As most already know, it really is important to try before you buy if at all possible. That’s the best way to make sure an instrument will be able to handle the tasks you need it to. Also, you need to learn everything possible about whatever machine you end up with. Test and verify every function you plan to use!! Even the RTB2000 locks up on occasion, and has some difficult to understand bugs that are still being worked through here.
After having used, primarily, a range of old Tek, Agilent and Rigol scopes prior to the release of the RTB2k, and having increased needs for additional MSO functions with decoding, the RTB seemed to be a potentially worthwhile addition to the stables. Primarily, RS232 decoding was needed here (at speeds at least up to 10 Mbps), but recently I2S, I2C and SPI functionality are becoming necessary as well. I can’t comment on I2S/I2C/SPI at this time, as I haven’t thoroughly tested these functions yet on the various scopes. A Rigol MSO5000 is also being evaluated and compared to the RTB2k, in the hopes that it will meet current and future decoding needs that the RTB2k can’t handle at this time.
So, after having had great success over the years with the Rigol DS2000 and DS1000Z series, thanks to a rich feature-set that has been critical to solving many development and troubleshooting issues, despite various rather minor bugs, I was really looking forward to getting the RTB2k's for the logic and decoding features, especially. At the time of the purchase, there wasn’t any way to “demo” a unit before buying, so it was understood that there was some risk involved – especially with such a new platform with limited details available.
Within minutes of firing one up though, I was quite surprised and disappointed to discover how limited the feature-set on the RTB was/is. I had slightly expected that R&S would absolutely pack the thing full of advanced features – especially in comparison to the “lowly” Rigols. At that time (launch edition period), there were only 4 math functions, and the wireless mouse functionality wasn’t there. Thankfully at least those two issues were fixed subsequently, so hat's off to R&S for that, and also for adding the Bode analysis functionality.
Somewhat sadly though, to this day, the DS2000 machines continue to get used over the RTB's because the faster decoding is necessary for so many of the projects here. (Yes, there are LA’s used too, but most of the time it’s necessary/desirable to see the actual signal.)
While the RTB2k is a great scope in so many ways, it turns out there are some surprising limitations for what is needed for the typical development projects done here -- especially for a scope in this price range. Though every scope has limitations and bugs, at the end of the very long development day, the necessary features to get the job done are the priority. Bugs, as long as there are workarounds, are just something you learn to deal with, and unless they cause lock-ups or crashes, aren’t understandable, or in some other way waste time, really aren't a big deal -- as long as you take the time to understand each bug and the workarounds. A much bigger issue is if a critical feature is completely missing though, or if it’s so buggy that it’s not usable.
The biggest RTB2k features that are truly outstanding for typical use scenarios here, are:
o The web interface (really well done, and the preferred way to “drive” the scope).
o Capability to use a mouse for direct control (however, there are some UI improvements that would be welcome, to more easily enable driving the scope entirely by mouse). One great advantage is no more achy arms from reaching out to the rack and twiddling knobs for hours on end, and also that the scope can be placed in more convenient locations. Since you don't have to physically touch the instrument -- it can be controlled remotely. And, a favorite here is the wireless Logitech M570, which now works very well, and allows the user to even stroll around while operating the instrument. Brilliant!
Side note: Personally, I still don’t like using touch screens on lab equipment for a variety of reasons, other than for entering lots of data, which isn’t too frequent with scopes in my experience. Using a mouse is so much more convenient, if the UI has been designed properly. And, when the scope can be placed close to the user, using knobs/buttons still works very well and can be pretty automatic, if the setup/layout is designed properly.
In the case of driving from the physical knob/button scope controls I personally find the Rigol MSO5000 intuitive and easy to use, and once you learn the menu structure (which doesn’t take long), it is an efficient and satisfying way to control the machine. Even the touch buttons on the screen are quite snappy on the Rigol – It’s just when you want to drag stuff around on the screen via touch that it gets really laggy. The RTB is laggy in this case, too – maybe not quite as much, though. The Rigol also works very nicely with the Logitech M570 wireless mouse.
Driving the RTB from the physical controls seems less intuitive than the Rigol to me, but then I’ve been using the Rigols for many years. It seems the RTB forces you to use the touch screen for some functions, rather than allowing full control via the buttons/knobs. This is disappointing. And not having separate vertical controls is also disappointing.
o Useful (but very basic) functionality and display in FFT mode that visually makes it easy to see what's going on.
o Decoding UI is really well done -- visually appealing and very functional.
o Decoding is quite smooth, reasonably feature-rich (with the limited available protocols), despite the significant speed limitations.
o Screen really is nice! (Both size and image quality.) Still, I don’t normally like using touch screens on lab equipment, except for typing in license codes or labels. Dragging around waveforms on a scope lacks precision and is quite laggy in this case (also true of the Rigol MSO5000)
o 10-bit resolution. Really not needed here for the vast majority of the time, but maybe it will be useful at some point. Certainly nice to have, but not a critical function.
The most significant issues:
o Significant (for purposes here) UART decode speed limitation. And, it is a hard limitation as I recall, with no workarounds. Beyond 3 Mbps, the decoding simply doesn't work. Even the ancient Rigol DS2000 series decodes at least up to 8 Mbps -- although it can be a bit painful, it gets the job done, and it is used for this quite a lot, to this day.
o Limited decoding types available. No I2S, FlexRay, 1553B, if you might need any of these (MSO5000 has these available, DS2000 does not, and the DS2000 lacks LIN). I2S, in addition to I2C and SPI, is becoming more important for projects here. And, only about 1.5 channels of decoding at one time...ouch! Even the DS2000 allows two fully independent TX/RX decoding channels.
o No Nth-edge trigger mode. This is something used a lot (on various Rigol scopes), and there is no runt trigger capability, though there is a search function for runt pulses, at least. Also, a rather limited range of trigger options, in general, as compared to the Rigol DS2000 series, and even the lovely little DS1000Z (which has paid for itself many many times over the years).
o No "Vertical Expansion" options, as in the Rigols. This allows vertical zoom to operate referenced to the center of the screen, which makes it quite easy to precisely zoom in all the way to a DC-offset waveform (for checking power rail noise, for example) without having to use AC coupling. This is used all the time here, and I haven't found a way to easily and precisely do this on the RTB2k's. It's been mentioned before, but I don't believe this is likely even on the radar for future RTB "upgrades" for some reason. Maybe I’m just missing something...
o Mechanically horrible probes. There is a lot of “stiction” that often prevents the probe “hooks” from properly grabbing a contact point, and it’s hard to rotate the probe clips on the probes easily. They’re the worst feeling probes I’ve ever used. Working with a limited budget here, this is quite disappointing, as buying a set of probes in addition to the relatively high cost of this scope, is quite painful. Especially when the probes offered by much cheaper brands have far better mechanical operation and feel.
o The Logic Probe cable is quite a crude design. Certainly doesn’t facilitate unplugging from the scope with any confidence that there is not undue stress being placed on the cable. For very little extra money, R&S could have designed a much better way to plug it into the scope.
Now, a Rigol MSO5000 is being evaluated, with very promising results so far, despite some minor bugs that remain, and the crude, by comparison, web interface, and slightly more limited mouse control.
Some apparent advantages of the MSO5000 (still testing, so these observations may or may not be true):
o More comprehensive trigger functionality, including Nth edge and runt.
o 4 complete decode channels, each of which are spec’ed to operate at up to 20 Mbps (not tested here yet).
o More decoding options, including i2s, which will be very useful if it works even reasonably well.
o Vertical Expansion functionality.
o Independent vertical channel controls. Scope can be fully driven with knobs/buttons, without having to touch the screen. Yay!! And, to me the shape of the knobs on the Rigol feel a bit better than the RTB, but that’s likely a rather silly distinction.
o Snappy UI (unless you’re dragging around waveforms via touchscreen or mouse). Now, not as “snappy” as a current Keysight, no doubt, but certainly not unpleasant at all. Running the FFT slows everything down, though, but this is also true for the RTB. Love the operation of the knobs/buttons, and the UI is quite intuitive once you get used the the “Rigol” way.
o Screen is plenty bright here – pretty close to the RTB.
o Two AWG’s (nice to have, I suppose, but not critical here).
o HDMI port. This is handy to have, despite and in addition to the Web UI, as it allows for another, larger, view of the scope screen.
o Great feeling probes, as with all Rigol probes I’ve ever used.
o Four FFTs available simultaneously. Not sure how usable this is ultimately, but at least it’s there...
Some early observations of things I don’t like about the MSO5000:
o FFT looks awful in comparison to the RTB unless you turn on “Color Grade”, and then it gets really slow, especially if you have all four FFTs running (which isn’t an option on the RTB). It even looks bad compared to the DS2000, so I hope this is something Rigol addresses in the near future.
o The decoding UI is rather crude looking compared to the RTB and lacks some of the clever UI design elements of the RTB.
o The web UI is extremely crude in comparison to the RTB, and really needs further work.
o The network settings are screwy and it’s hard to get static IP parameters locked in. Luckily, Wireshark monitoring doesn’t show the instrument “phoning home” yet, despite the bizarre network settings behavior. The online upgrade option has not been tested as this is a STUPID function for any networked lab instrument (security/privacy), and will never be used here. Micsig is trying this BS approach to firmware updates, too. UNACCEPTABLE!!
To wrap up – while I love much about the RTB series, it is pretty expensive for the functionality, as compared to the Rigols at least, and I’d guess as compared to Siglents and others, as well. To get faster/additional decoding options with R&S, you’d have to pay for at least the next tier up and that’s well over $10k, I would guess.
At this time it appears that even the low-end Rigols continue to offer critical functionality that the RTB lacks – which in this case keeps them in use here. And, they are similarly enjoyable to operate in my experience – as long as you don’t have a passion for touch screen operation. I also remain hopeful that the MSO5000 will fill in the rest of the functionality gaps.
So, none of this is intended to be comprehensive, and I’ve likely gotten things wrong. It is just a basic, non-detailed overview of some of the observations based on use cases here, that I hope may be helpful to others. I’m sure there are many folks who have requirements that are different, and for whom the RTB would be the perfect match. If money becomes much less of a factor in the future, I will certainly be looking at some of the more advanced R&S scopes because there is so much about the RTB that I really do like.
One thing that makes the R&S products really stand out from the Rigol offerings is that Rich is here on this forum, actively listening to, and helping, users all of the time. As for Rigol, hmm…..
Finally, and again – don’t forget to play before you pay if at all possible, and make sure to learn the critical quirks of whatever instrument you end up with, lest you be tripped up for resting on your laurels.