User Interface of Major Oscilliscope Brands? 281
teddaw152 writes "I've been tasked with ordering an oscilloscope and a logic analyzer for use in a university physics lab, and have found several models that will likely suit our technical needs from the major manufacturers (Agilent, Tektronix, and LeCroy). However, I personally have only used legacy HP scopes, and thus I have no idea what modern features are must haves and which brand's user interface is the most intuitive. Is there anyone out there that has used modern Tektronix/Agilent/LeCroy scopes side by side and can comment on their thoughts from the purely subjective side?"
Comment removed (Score:3, Informative)
Agilent was HP (Score:2, Informative)
Damn, but they're getting good... (Score:4, Informative)
I saw a LeCroy we have -- about $10K -- that was freaking amazing. Plugs into a network, has USB, can store waveforms, zoom, virtually unlimited capture, freaking AUTOMATICALLY figured out which serial standard was being used to generate the waveform (the first -- and perhaps only -- time that "autoconfigure" really did the job), etc. They're good. Unless Agilent and Tektronix have come a looong way, LeCroy is going to be the one to beat.
$.02
Tektronix seems to be the best in general (Score:4, Informative)
Advice (Score:5, Informative)
A few points of advice.
Agilent lets you connect a scope to the logic analyzer and display both waveforms on the same screen.
I did extensive evaluation on the UIs of Tek, Agilent, and Lecroy when I bought. All were approximately comparable. All had things that were great and some that sucked. You should be able to get a demo from sales and possibly keep it for a month.
Do you really need / want a logic analyzer? Unless you're doing FPGAs or pure-digital boards with lots of parallel buses, get a Mixed Signal Oscilloscope instead. They'll decode RS-232, SPI, I2C, and so on and display it on-screen. My high-end scope and logic analyzer lack these features and I am kicking myself. I mostly do microcontroller work and an MSO would have been far more usable. I'm not sure if I have ever even used the logic analyzer.
Re:Damn, but they're getting good... (Score:3, Informative)
Coworker junked his LeCroy for the new Tek DPO4000's. The LeCroy was okay, but the UI was a bit weird and it broke a lot. The only advantage he said it has was you could plug in a keyboard and mouse and put labels on the screen easier.
On request, Tek added the ability to label traces with the later DPO4000 software, although you have to do it with the on-device wheel.
LeCroy (Score:2, Informative)
It runs Windows 2000 and takes a cup of coffee to boot up but runs nicely.
We tried Agilent scopes (we were able to try-before-buy) and found them easier to use, more compact, less bloat that the LeCroy.
I think its hard to go wrong with modern oscilloscopes.
Re:Evaluation units? (Score:5, Informative)
I second this - if you really don't know what to buy, then do the following:
Find your local Agilent (HP), Tek and LeCroy sales reps and give them a call with your needs, and let them recommend you which line of 'scopes will fit your needs best (do you need mixed signal, digital decode, etc). Then go to their websites and research those scopes to narrow down the models to 1 or 2 at most. (They all make tons of scope models, and each has their own ton of options that can be bought with them. The sales guy will help you narrow down that list.)
Call up the reps again and ask for a loaner to try them out - they'll normally give you a week or two to play with them. Play with all the scopes and try to do what the people in the lab do. At the end, find out what features you like, which were redundant, and phone the reps again asking to see if a different model may suit your needs better after having used them.
Lather, rinse, repeat.
If you're going to be buying many of them, mention it to the sales rep, and also the fact you're buying for university - they'll be more accommodating in loaning you units. One thing they would appreciate is feedback on the units - if something really sucks, they want to know about it
Once you've got a list of several scopes that will suit your needs, it's discussion time about prices and discounts.
But do take advantage of the fact that the sales reps will often loan you equipment.
Re:Damn, but they're getting good... (Score:4, Informative)
LeCroy is all right (stuck with them through grad. school), but don't ever try to get the circuits from them in case you have to fix something with it yourself. Your best bet in that case is to find an electronics expert in the area who is willing to share his diagrams with you. LeCroy has been *really* closed-source about releasing their plans.
My big problem with LeCroy scopes recently is that their knobs seem to gum up (har-har) a lot, and nothing is more frustrating than trying to adjust a DC-offset, only to have the entire trace disappear off the screen because of some dirt in their goddamned sealed knobs. Even getting to the things is an afternoon-long job.
In terms of dedicated digital scopes, I've also a lot of experience with Agilent (HP) and Tektronix. I'd personally give instek a miss (too much aliasing, not enough capabilities, though the newer ones might be better than the 806C). One of my colleagues, who is knowledgeable about these things, uses nothing but Tektronix, and I have to admit that the ones I've seen lately are awfully nice.
For cheaper USB-based scopes, TiePies are all right. ECON-series digitizers are all right, too, though maybe not exactly what you're looking for.
Re:What do you need? (Score:3, Informative)
It probably depends on how you look at your use of the scope. If you define your need as "look at the signal" then it probably hasn't changed much. But if you define your need as, say "determine if the rise and fall time of these signals are in spec, and check the channel to channel skew", then you'll find that you can do a lot more with a modern scope.
Both boxes and PC plug-in scopes offer processing capabilities to do that sort of analysis. That's probably what you wanted anyway; you're just used to having to do that extra work yourself.
Re:Hey, this question is interesting! (Score:5, Informative)
User interface is largely irrelevant. As long as the controls you need are there, you can work it out.
More important is whether the scope has the capacity to display waveforms in the frequency range matching the circuitry you're going to test. It's no good choosing a favorite brand of old 20MHz dual-trace when you want to measure a 2GHz computer circuit, although it may be perfect for most audio or RF engineering (that's where a scope really shines). And check the probes, too -- make sure the ones you're looking at work for the scope and the circuit. You'll need a bit of theory to choose the right ones, so study up.
Re:Software? (Score:5, Informative)
I would like to add a few ideas to the above. I work at a facility that actually uses these things.
We have some TDS5104B's. They're great scopes, don't get me wrong, but the Windows interface might throw you. I won't go through all the downsides of a Windows OS on a scope, because they're pretty much the downsides of the Windows OS on anything, but the upsides are:
* You can run things like Labview and Matlab right on the scope, and there are libraries that let you talk to the scope itself and control it;
* You can remotely operate the scope via standard VNC programs; and
* You can run programs on the scope that you would otherwise need another computer to do.
As an example, I've been able to download new firmware code to a board via an Altera Stand-Alone Programmer program and a USBBlaster, and watch the result on the scope from my office down the hall from the lab. Another engineer rigged the scope, an Ethernet-equipped function generator, and Matlab on the scope to make a homebrew Bode plotter.
That all said, the TDS5000 series is old and not likely to be sold by Tek too much longer. The model we have, the 5104, is no longer available. There are other models.
The DPO4000 series is comparable to the TDS5000s, except they're half as big, don't run Windows, and can decode serial (e.g. SPI, I2C, or UART) data for you (and let you trigger on those serial patterns with an add-on chip). For our next scopes, we're looking at the MSO4000 series, which are DPO4000s with 16 logic inputs as well, so you can see everything on both the analog and digital sides of an ADC, for example.
The DSA8200 is insanely expensive ($150k or so once you buy the probes) and probably not something you want to let students near. If you aren't designing things like 3.125 Gb/s data links (e.g. SATA or XAUI), these are a waste of money.
The thing is... 90% of the time, we don't need anything that fancy. Which is why we got about half our engineers Tektronix TPS2024s [tek.com]. They're small, simple, portable (battery or wall powered) digital scopes, 200 MHz, with 4 isolated channels. Isolated channels are great in that you can use them to look at differential signals without needing a special differential probe or needing to rig two channels together and use the math channel to take the difference (which you can't trigger on). They also have CompactFlash slots which can be used to grab waveform and setting data and copy it to your computer as CSV files. I have mine set to save everything to CF when I press the PRINT button.
For even smaller work, Agilent has some neat two-channel handheld scopes, their U1600A series [agilent.com]. I saw some in their demo trailer this week, and the screens were nice and fast, unlike older handheld scopes and scope/meters.
Re:Damn, but they're getting good... (Score:4, Informative)
Missing criterion (Score:5, Informative)
Everyone expressing an opinion based on experience is dead right, teddaw152 - I've used all three and can say I see no BS.
But you're missing a most important criterion - how easy will it be to offload your data, because I don't care what you think your requirement is or will be, you're going to need this badly - or the next user will.
For any given model of features/performance/price tickling your fancy, insist to see the full configuration used to offload data to a PC.
I'm dead serious, full configuration. Do not ever accept rep claims of way-easy-all-our-customers-do-it, do not accept quick looks at user manuals showing code slices that make it all so obvious.
Do not accept that USB, GPIB, or Ethernet obviously imply that you can do this.
Do require code that:
1. Is in a language that your site will support long term
2. Allows for external configuration of the scope
3. Allows for external software trigger of recording
4. Allows for data acquisition by a PC
5. Allows for usable data, post acquisition
PLEASE USE THIS DEFINITION ONLY FOR THE WORDS "Allows for" IN THE ABOVE:
1. Full source code in your selected language
2. Full clarity of hardware interface required - price, performance and gotchas
3. You get a peer review of this
For "usable data" this damn well means that the data feed of (usually) start-time, stop-time, delta-time and Y values or X-Y pairs can not only be read in, they can be easily read in, easily put into another format, and easily absorbed by other post-processing software.
And for god's sake, make sure that status register and SRQ handling - in software - is clearly explained, and that you get routines for SRQ handling, and THE RULES FOR WHEN TO USE SRQs or NOT (typical GPIB issue).
I disclose that I have inside info on the brands you consider so I can only give these hints on approaching the problem. I cannot be trusted to be objective - due to associations - on saying which brands/models excel on this.
But I can be trusted to tell you this - your rep for any given brand will shuck and jive a *little* (and that really is an OK thing, it's a people skill), and he/she will give you assurances out the yin-yang (that's their job) - but they fucking-a well know what you're asking and will give you the straight dope if you are friendly while being persistent.
Please believe me, if you overlook this criterion now, you're almost guaranteed to screw the next guys after you - I don't believe you'd want that if you had a choice.
Cheers, best luck.
Re:I'm not trying to troll, I swear (Score:5, Informative)
Re:Hey, this question is interesting! (Score:5, Informative)
What is your budget?
Basic osciliscopes can be picked up secondhand pretty cheap either off ebay or at places like HAM meetups as more and more people are upgrading to a digital storage oscilliscope (DSO). I'm not sure if anyone makes them new anymore.
Most scopes are dual trace. I would avoid single trace scopes because you can't compare imput and output with them. Four trace and above scopes tend to be expensive (i've never actually seen a three trace in person or for sale, I think I may have seen one in a marketing pic once but it may have been a four channel with one of the channels turned off).
Check the max freqency, if all you plan to do is play with audio frequency and lower circuits any scope is fine but if you want to do microcontroller work then you need something faster.
If you plan to do any digital/microcontroller work I would strongly reccomend a DSO. There are some cheap chineese DSOs on the market now that are only a few hundred dollars. The max frequency on them isn't great but it's just about high enough for working with pics and similar.
PC based scopes are another option, i've never liked the things myself though.
Re:Agilent was HP (Score:1, Informative)
For network analysers, VSAs and the like, I'd go with Agilent every time. For a DSO, Tektronix had the edge, although Agilent's new little 5000 series scope has put them right back in the game.
Re:Evaluation units? (Score:2, Informative)
Re:I'm not trying to troll, I swear (Score:5, Informative)
Let's all lighten up. O-scopes are expensive, and used for so many things that it's impossible for us to say use Brand X Model Y. The question IS really specious and ill conceived at that. That said, I cringe at the thought of buying one for a department in a university or even a researchy corporate job, there are just too many different use cases and needs.
Plus, the UI is the part I care about the least. In fact Lecroy in the >1GHz range are my favorite scopes, but the UI is terrible.
What we should offer is a framework of asking better questions about this product. There are more options than a car, and the price is usually higher
1) What bandwidth range are you looking for? (Note: this is directly correlated with PRICE, so you do not buy more than you need) Do talk to your sales rep, and tell him what kind of signals you're measuring (say USB, SATA, ethernet...whatever). Do not simply assume the nyquist rate for your fundamental, and get that fast of a scope. Even if it worked the way you think it works, you will hurt yourself. Your rep will be happy to explain the architecture of your scope input, and help you find the right frequency.
2) What kind of probes are important to you/what is your application? Scopes are accessorized, heavily. There are various types of active/passive/differential/current/etc. probes out there, some brands are better than others for a given application. Some diff probes require solder on tips, these can be very, very expensive (but also very handy, depending on what you're doing).
3) Are you going to be doing compliance measurements/mask measurements/protocol analysis etc? Will you need to add new masks later? Have your rep demo these key features, ask about upgrades, support and expandability. Get him to take a measurement on your devices, make him show you how well it works. Often they don't work as well as you need.
4) Your corporate/university IT nazi's. All the fancy wizards and auto-testing tools are no good if you are going to be forbidden to have a scope on your corporate network, particularly if those rules are targeted at Windows based tools. Almost all scopes are Win95/98/2k based. Think about the infrastructure you will need to be compliant.
5) Expandability: for some kinds of measurements you will want to interface your o-scope with some equipment. One other poster here talked about linking to a logic analyzer. Many will interact with matlab/labview/etc. Some need licenses...investigate
6) UI's can be important, depending on your audience. If I were buying a scope to be used by my lab techs, I would choose one that I could script and wizard through, flashing pictures of what to measure and automatically logging data to the appropriate spot. For me, if it's worth using it's worth learning to use, UI doesn't matter to me.
Price is an output of these functions. The more you want, the more it costs. Start with what you NEED at a minimum. Use your sales reps, they are engineers, they are knowledgeable. Use your brain and ask dumb questions, and play one vendor's answers against another to figure out what's going on.
You can also consider leasing equipment, a good way to figure out what works or what doesn't.
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Re:USB 'scope FTW (Score:2, Informative)
Get one without Windows (Score:4, Informative)
I use oscilloscopes almost daily in my job as an EE, and I've found that I very much prefer the scopes that don't use Windows in any shape or form to the ones that do. If a scope requires a mouse, it's really a portable computer with an integrated DAC subsystem. You have to wait for it to boot up and shut down, and you have to have the flat space necessary to drive the mouse (or use a trackball). They are also generally less responsive to input and take longer to change modes than an embedded-system style scope.
My current desk unit is a Tektronix MSO 4054, which is ideal for what I do. Everything is adjusted using good old-fashioned knobs and buttons on the front panel. I also use several higher-end Teks that run Windows and various Agilent scopes, both from the 54600-series and the Infinium series.
It's true that the Windows-based scopes can often run other software and do more detailed analysis of data. However, I prefer to use the scope to acquire data, store it on a USB drive and then do that analysis at my desk later using my main computer.
In our corporate environment, having oscilloscopes on the network is frowned upon by our IT.
My dislike for oscilloscopes that run Windows is shared by most of my EE and technician colleagues. Non-EE types (physicists, MEs) seem to like the Windows interface because they use the scopes less often and they feel more at home with a PC-like interface.
In another vein, I despise touch screens. This is simply my personal preference, as I realize that many people like the way they link the data on screen to actions. I just hate fingerprints, and the tactile feedback provided by real buttons and knobs is far superior in my mind.
Re:Hey, this question is interesting! (Score:3, Informative)
If you have a fairly good laptop, with, regrettably, Windows then the USB oscilloscope modules are quite good. There the main cost is the D/A converter and the higher the bandwidth, the more it will cost. I have a fairly basic two channel 50MHz model which seems ok for my own use.
Real oscilloscopes are wonderful things but they cost a lot and take a lot of space. I love the old Teks/HPs (now Agilents) and they are beautiful pieces of engineering but when buying s/h, it is better to check them out in person which means a good surplus dealer om your town.
Re:I'm not trying to troll, I swear (Score:3, Informative)
Absolutely. I spent a frightening amount of my time grad. school staring at a Tek TDS744A, and I knew my way round its interface much faster than the embedded processor could keep up with my commands. On the odd occasion that I've used a newer Tek ’scope, not only have I immediately known my way through the menus, it's also been able to keep up with me.
Agilent ’scopes have a reasonably well layed-out UI (though it's a bit of a culture shock), but LeCroy's ’scopes are just impenetrably different from Tek's.
Must be joke (Score:3, Informative)
Spent a minute trying to understand the above comment... it must be a joke. Straight diagonal lines would be a characteristic of a digital storage scope with serious Analog-to-Digital converter problems.
Although it wouldn't be used in a university physics lab, I suggest Slashdot readers download a free PC sound-card-oscilloscope program. They are basically *free* Digital Storage Scopes with a limited input frequency of 44KHz to 96KHz depending on the particular sound chip in the PC. Many of these programs include spectrum analysis and FFT features.
These are invaluable for audio and other low frequency work. It's necessary to scale the input to the sound card to about 1-2 volts peak-to-peak max, because these programs are working with the audio line-input signal. A couple of $0.40 op-amps work fine. I've used *free* sound card oscilloscopes to verify MIDI in/out streams from synthesizers, RS-232 signals, and the design/repair/calibration of hundreds of guitar stompbox circuits.