User Interface of Major Oscilliscope Brands?

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?"

Comments

Please...

[Anonymous Coward]

Not another scopes trial!

I'm not trying to troll, I swear

[jeffmeden]

Are you really going to come to slashdot with a question including

"I have no idea what modern features are must haves and which brand's user interface is the most intuitive."

The clear answer to your dilemma is that the task should have fallen on someone else. Who is going to be using these things? If it's you, maybe you are best to stick with legacy HP scopes until you figure out what it is that you want.

Re:I'm not trying to troll, I swear

[Anonymous Coward]

Brand is definitely not important, but if you don't need the modern features or don't know what they are then why are you upgrading the scope at all?

I've used scopes from all manufacturers and by far the most important consideration is what is currently being used. You don't sound like you are the one who will be using the scope so ask the guy who will.

There is nothing more frustrating than having a department full of Tektronix scopes and people who have used those for the last 3 years only to have to battle with an Agilent simply because the buttons are in a different place.

Re:I'm not trying to troll, I swear

[Austerity Empowers]

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.

Advice

[albeit unknown]

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:Evaluation units?

[tlhIngan]

I thought the major companies offer a way to evaluate them before committing to buying one. I am pretty sure Tek has such a program. I would look into that first.

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:Agilent was HP

[jasonmantey]

From my experience in a calibration lab for two different major electronics companies in the past few years, I can wholeheartedly say that Agilent products are generally the best of said brands. (Needing recalibration less often, better interfaces (IMO), less glitches in software, better build / support, etc.). That said, they are often the more expensive brand. At an academic research lab, this factor may take the most consideration depending on your funding sources and reliability. FWIW, we viewed most of the Tektronix equipment as junk and would opt to use the Agilent equipment when available (but, "junk" is a relative term).

Re:Software?

[Anonymous Coward]

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. 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. I saw some in their demo trailer this week, and the screens were nice and fast, unlike older handheld scopes and scope/meters.

Missing criterion

[earlymon]

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.