Please recommend oscilloscope for robotics research - Page 1
Forum section: electronics / testgear

author: eeguy
author_rank: Regular Contributor
timestamp: August 02, 2016, 11:21:43 pm
content: Hello, I am considering to purchase an oscilloscope for robotics research at graduate school level. Having the ability to record the data during the experiments is nice. Good to have four channels. Any good recommendation appreciated. Thanks.

author: ebclr
author_rank: Super Contributor
timestamp: August 02, 2016, 11:37:11 pm
content: Case you have a deep pockethttp://www.keysight.com/en/pdx-x201842-pn-DSOX3014A/oscilloscope-100-mhz-4-channels?cc=US&lc=engCase nothttps://www.adafruit.com/product/2145

author: tautech
author_rank: Super Contributor
timestamp: August 03, 2016, 12:17:31 am
content: Quote from: eeguy on August 02, 2016, 11:21:43 pmWelcome to the forum.Yep, 4 channels are nice IF you need any HV capability for all 4, seldom you will in my experience.A 2 channel MSO is then a viable option and offers more total channel #'s too.In this case I would suggest a SDS1000X+ series with the MSO/LA option.http://www.siglentamerica.com/pdxx.aspx?id=4688&T=2&tid=1Or it's big brother, the SDS2000X series, these are available in 2 or 4 channels and MSO/LA option.http://www.siglentamerica.com/pdxx.aspx?id=1488&T=2&tid=1

author: Hydrawerk
author_rank: Super Contributor
timestamp: August 03, 2016, 12:19:51 am
content: Consider some from Keysight DSOX2000A series. But only you decide what you really need. Yes, this scope was introduced in 2011.

author: PartialDischarge
author_rank: Super Contributor
timestamp: August 03, 2016, 02:22:40 am
content: definitively dont get an usb scope. Cost and spec wise, either get a rigol or a siglent which are 'expandable' in memory and will give you more features than you needThe forum has lots on threads about first buy scopes like these.

author: Hydrawerk
author_rank: Super Contributor
timestamp: August 03, 2016, 02:30:45 am
content: Quote from: blueskull on August 03, 2016, 01:29:00 amThen you must consider GW Instek GDS-2000E.http://www.gwinstek.com/en-US/products/Oscilloscopes/Digital_Storage_Oscilloscopes/GDS-2000E

author: rstofer
author_rank: Super Contributor
timestamp: August 03, 2016, 02:31:55 am
content: There are a number of threads here about the Rigol DS1054Z 4 channel scope (and you do want 4 channels). I sure like mine.

author: nctnico
author_rank: Super Contributor
timestamp: August 03, 2016, 02:41:30 am
content: I'd go for a 4 channel scope and a simple (USB) logic analyser for hunting digital problems. I have an MSO on my bench but so far I have not used it. 4 channels gets me around and for real digital problems I pull out my logic analyser.

author: rstofer
author_rank: Super Contributor
timestamp: August 03, 2016, 04:56:19 am
content: Dave has done a few videos of the DS1054Z Here is he summary:You can search YouTube for the others.

author: lem_ix
author_rank: Regular Contributor
timestamp: August 03, 2016, 08:56:26 am
content: 4 channels is always nice and decoding, preferably with canbus. I'd go with the instek 2000e(good value) but anything along those lines would do. Personally pretty happy with my R&S/Hameg hmo.

author: eeguy
author_rank: Regular Contributor
timestamp: August 03, 2016, 03:46:18 pm
content: Thanks.I watched the video about the DS1054Z. The guy mentioned that the vertical scale of all four channels have to be the same. I guess it would be better if they could be set independently.A potential use of the scope is to measure and record the power consumption of the motors during the experiments. For this application, should I use an oscilloscope or some other equipment?

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 03, 2016, 03:52:27 pm
content: You can set the vertical scale individually for each channel, but you have to use the same knob for it.So that means that you have to select the active channel first, before you use the knob.

author: eeguy
author_rank: Regular Contributor
timestamp: August 03, 2016, 09:11:21 pm
content: Quote from: pascal_sweden on August 03, 2016, 03:52:27 pmThanks. Can this scope change the vertical and horizontal scales of each channel automatically?

author: tautech
author_rank: Super Contributor
timestamp: August 03, 2016, 09:17:45 pm
content: Quote from: eeguy on August 03, 2016, 09:11:21 pmAll DSO's have "AutoSet", a button that configures the scope based on the signal input. Primarily it's used by scope newbies as it often resets a scope to what IT thinks is best, not the user.Auto Set is the only auto change of vertical and horizontal settings.It can sometimes be useful however most experienced users prefer to "drive" their scopes.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 03, 2016, 10:40:42 pm
content: Quote from: tautech on August 03, 2016, 09:17:45 pmOn the risk of sounding a lot like Wuerstchenhund now. I made quite odd experiences with my LC9300 series, which also deploys advanced triggers via AutoSet sometimes if it feels the need.But yes, that would also be a recommendation for an LC9300 or one of the successors with DPO-like capabilities. I _really_ like their automatic analytics, which determine all kinds of parameters on the go. Plus, they are quite cheap on Ebay...and if you get the hard drive option, you get unlimited storage.(Be aware that most of the FDD drives are toast, however)

author: saturation
author_rank: Super Contributor
timestamp: August 04, 2016, 12:10:29 am
content: You can use a wattmeter but the scope will allow you to view instantaneous values. This is most helpful in determining which actions consume more power.E.g.Place VDC across the motor on say CH1, a small value dropping resistor in series with its power line or a sensitive [ and expensive] DC current probe set on CH2. For dropping resistors you can convert CH2 to current if you can apply math function to the output, say CH2= CH2/R, were R is a constant in ohms to read output as amperes. You can then set CH3 = CH1x CH2 for instantaneous watts.For total power integrate CH3 say set CH4= INTG(CH3).Quote from: eeguy on August 03, 2016, 03:46:18 pm

author: eeguy
author_rank: Regular Contributor
timestamp: August 04, 2016, 01:14:10 am
content: Quote from: saturation on August 04, 2016, 12:10:29 amThat is great! What suggestion do you have in the following two cases:1. Measure and record the power consumption of the entire robot which consists of more than one motor.2. Measure and record the power consumption of several motors of the robot at the same time.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 04, 2016, 01:41:01 am
content: Hi,To the OP you might want something that can do I2C and SPI decoding. You probably have I2C and SPI devices on the robot.Regards,Jay_Diddy_B

author: saturation
author_rank: Super Contributor
timestamp: August 04, 2016, 02:33:19 pm
content: To measure the power consumption in toto, put a DC wattmeter in the V+ of the robot battery. This will give total power consumption. You can buy wattmeters anywhere, there are often sold in the RC hobby market; logging, non-logging, low power, very lower power, miniature etc.,To measure power of each limb you put a wattmeter on V+ of the limbs.Note, your choice of devices matter, DSO are only accurate to about 1-3% and DMM are far better but they do not show instantaneous power well. Also if you are using very low power, DC wattmeters, DSO and DMM have limits. Low low power power applications require low-load wattmeters that use hall effect transducers, which raise the cost of the device.Be careful on your choice of DSO, e.g. the eevblog 'popular' Rigol 1054Z has reported bugs in its voltage readouts, and so far it may have others yet unreported. Any measurement bugs will give calculation errors even if the calculation algorithm is correct, and the waveforms appear be fine. So, buyer beware.Enjoy.Quote from: eeguy on August 04, 2016, 01:14:10 am

author: rstofer
author_rank: Super Contributor
timestamp: August 04, 2016, 03:24:48 pm
content: As stated, yes, the vertical V/div can be individually set. You briefly push the channel button to select the channel and then turn the knob. The scale will be shown at the bottom of the screen.No, you can't set the time/div individually. Why would you want to? Normally, we use multi-channel scopes to view the relationship between signals and that implies the same time base.You do power measurement by installing a shunt resistor on the + lead of the power source (battery, I assume) and then using a high side sense amplifier IC to measure the voltage drop. This results in an analog output voltage proportional to current. Another op amp will be used to scale the voltage (could use resistors) and the two signals will be sent to a uC ADC inputs where the numbers will be crunched. Pretty easy!http://www.linear.com/products/Current_Sense_AmplifiersIndustrial shunt resistors are set to drop 50 mV at full scale, whatever it is. 1A, 100A, 1000A, they all drop 50 mV at full scale.Decoding: So, the basic DS1054Z doesn't include decoding or the optional 100 MHz bandwidth and you have to dance with hacking the scope to get them (actually, they come with the scope with a time limit). This process is well understood. For the first time yesterday, I went live with decoding SPI with a 1 MHz clock rate. I am working with a chip that needs a LOT of SPI signalinghttp://www.mouser.com/ProductDetail/WIZnet/W5500I think the scope will earn its keep before this project is over. There are limitations to the decoding because the scope only decodes what it displays, it doesn't look through the buffer. That's ok, once I get the basic transfer functions written, the rest is just details and they can be debugged in the uC using my favorite tool: printf();

author: Assafl
author_rank: Frequent Contributor
timestamp: August 05, 2016, 08:41:19 am
content: Not a scope - but has two channels logging DMM (at 8k sample rate) is the Mooshimeter.As far as the story goes it was developed by engineers working on real robots (the dangerous full sized ones) so they designed it to be inexpensive, high A/D resolution, can be tie-wrap tied to a robot arm, has two channels and can be read remotely via Bluetooth.The software and firmware still have some issues, but the developer is working hard to resolve most of them. It is becoming a rather useful device for remote monitoring and logging...https://moosh.im/

author: eeguy
author_rank: Regular Contributor
timestamp: August 30, 2016, 12:14:28 pm
content: I am concerned about some of the issues mentioned in the video:Have those issues been fixed?

author: Fungus
author_rank: Super Contributor
timestamp: August 30, 2016, 01:39:50 pm
content: Quote from: eeguy on August 30, 2016, 12:14:28 pmUmmm.... some of those aren't even 'issues'. It's mostly just a Rigol-bash by somebody who didn't bother to learn to use his 'scope.eg. The thing about "channel buttons not working"That's totally by design. The first press is to set the active channelifit's not already active (which you can see by ahugemarker on screen). He says "button didn't work" but yes it did - you can see the marker change at the bottom of the screen. Thesecondpress will then turn the channel off. This is common to many (all?) oscilloscopes which don't have a separate set of controls for each channel, not just Rigol. He needs to either learn to use his 'scope or pay for the separate controls.The fan? Yes, some forum members have replaced the fan for a quieter one.The vertical movement? Yes, it looks bad if you savagely yank the knob around in a Rigol-bashing video. In real life:a) There's a little marker at the side of the screen which adjustsfasterthan the trace. Use it.b) You'll quickly get the 'feel' of the knob and learn to do it.It's not ideal, some forum members have replaced the rotary encoder knob with a fatter one (this helps a lot). Some have even replaced the encoder with a clicky one. It doesn't make it unusable.Could it be improved? Yes. Who knows what goodies the next firmware will bring?If you're hopelessly ham-fisted or just want something a bit more 'refined' you can go for a different brand but you'll lose outbadlyin terms of technical specs (bandwidth, channels, memory size, serial decoders, etc).The next real step up from a hacked DS1054Z in terms of spec.andniceness will cost you $1200+. Your call.

author: rstofer
author_rank: Super Contributor
timestamp: August 30, 2016, 02:22:25 pm
content: Quote from: eeguy on August 30, 2016, 12:14:28 pmEverything he mentioned, with the possible exception of the scope probes, is exactly correct. These human interface issues are exactly the kind of things that should lead you to buying something else. There are many other choices that are much better behaved. Perhaps one of the GW Instek models - they are known to be perfect.Oh, wait! I bought the DS1054Z and the first thing I did was hack the unit to get 100 MHz bandwidth and keep the decoders. Next, I replaced the rotary selector switch with one having a detent mechanism. I have the replacement fan but I haven't found the noise to be compelling enough to open the unit up again. Yes, the UI is slow under some conditions; conditions I just don't run across very often. Or, if I do, I just deal and move on.Channel selection works exactly the way it is described in the video. And it is the ONLY way it can work if the scope doesn't have separate controls for each channel (some do). Before you can adjust a channel, you have to select the channel. Seems pretty right to me!Trace colors: Yellow, cyan, purple and blue. Yes, the purple and blue are 'similar'. But it's a whole lot better than using red for which a high percentage of the adult male population have a vision defect. Red is a horrible color to use.Are you going to get a multi-thousand dollar scope for $400? Probably not! But if those issues are a concern, you would be better off buying a higher dollar scope. Clearly, the GW Instek will be much better - it kind of makes you wonder why the video author bought the Rigol.

author: Assafl
author_rank: Frequent Contributor
timestamp: September 01, 2016, 07:14:21 am
content: Quote from: rstofer on August 30, 2016, 02:22:25 pmThe reason he seems to use it (all the time) is that with a single channel enabled (at 1GHz sample rate) he uses the DS1054Z to measure 400MHz signals with it. Attenuated quite a bit by the input filtering for sure - but still.He also seemed to admit in later posts he was annoyed and ranted... But he uses the scope.A funny aspect of these types of rants and criticisms is that they result in selection/observation type biases. I never had any issues with the selection knob until I read all those who couldn't click straight. Guess what - suddenly it became a problem.... There is a psychological aspect to oscilloscopes especially on the low end where users can't afford shrinks.

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: September 01, 2016, 04:22:01 pm
content: I'll (of course) second the Keysight scopes. Especially the 3000 X-Series or the 4000 X-Series if you have the budget for it.Of interest to you might be data logging with the BenchVue software, the power analysis applications, and/or the remote interface capabilities that allow you to control the scope from a PC or mobile phone. We also have educational pricing available for universities.

author: eeguy
author_rank: Regular Contributor
timestamp: September 02, 2016, 05:56:02 pm
content: Which scope would be the next step up from the DS1054Z? How Tektronix scopes compared with the Rigols?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 02, 2016, 06:35:31 pm
content: Quote from: eeguy on September 02, 2016, 05:56:02 pmWell, Tek just came out with the new TPBS2000 which is its latest entry-level scope - at least feature-wise (price-wise, not so much). There's a thread with more details around in this forum.As to Tek in general, all I can say is if someone thinks the UI of the Rigol DS1054z in that video is laggy then he hasn't seen a Tek yet. I've a MSO3000 (at least until Monday after which it goes to a colleague), and even with the latest firmware the UI is pretty slow if the scope isn't doing anything special. If it is, then the UI pretty much locks up. Also, the whole UI is pretty cumbersome to use, it's no joy. And that is a scope that sells for around $10k. Tek had great analog scopes but its DSOs were never great but mediocre at best and in many cases just god-awful.For a very cheap entry-level scope I'd consider the GW-Instek GDS-1000B and GDS-200E, simply because they seem to be a lot more mature than the Rigols. If you can afford to spend a bit more, the Keysight DSOX2k Series or the R&S HMO1202 make good choices. Above that there's the DSOX3000T, but unless you need one of the less common serial decode standards it supports then the LeCroy WaveSurfer 3000 offers a lot more for a lot less money.Quote from: blueskull on September 02, 2016, 06:06:37 pmYou'll find that in terms of functionality you usually get more from LeCroy than from Keysight (some features you only get from LeCroy, and for others the equivalents often lack functionality). Same is true re. performance, aside from the low-end and the lower mid-range where KS really offers excessive waveform update rates, but further up the ladder it shows that LeCroy has the stronger architecture compared to other scopes which are mostly based around proprietary ASICs.On the other side, LeCroy's entry-level (WaveAce, WaveJet, all rebadges) isn't even worth considering.QuoteI can only concur. I really tried to like that MDO3000 but it's pathetic slowness, the stupid UI and the overall disappointing performance means I can't see it gone fast enough. It's no joke, it really sucks all the joy out of the work. I almost feel sorry for its new owner (but then, he I warned him but he still wanted it).

author: eeguy
author_rank: Regular Contributor
timestamp: September 07, 2016, 01:18:36 am
content: The Keysight DSOX2k Series seem to be a few years old. How come they don't have new products in this series?Looks like the DSOX2k Series have 1Mpts as max memory depth and 2GSa/s as the max sample rate. One of the uses is to measure and record the power consumption and current of the motors or the robot. Will such specifications be sufficient? The GW INSTEK GDS-2104A and 2204A have display memory depth of 2Mpts and cheaper than the Keysight. However, Keysight seems to be a better brand. Not sure if 2Mpts is overkill. Why suggestion? Also, shall I go for 100MHz or 200MHz model?

author: Faith
author_rank: Unknown
timestamp: September 07, 2016, 02:33:32 am
content: Don't forget that with the Keysight 2000A the 1Mpts of memory is an option. See:MSOX2000-010: Memory upgrade - 1 M for 2000 X-series.If that's the route you're going to take however I would recommend buying it from Keysight's Premium Used store on eBay.From over there the top-of-the-line MSOX2024A (200MHz 4+8 Channel) costs less than the MSOX2002A (70MHz 2+8 Channel) would if you were to buy it "new."The MSOX2024A which I borrow on occasion was purchased from there and it really is indistinguishable from a used unit. It's thoroughly refurbished and comes with new calibration and new five-year warranty.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 07, 2016, 05:11:15 am
content: Quote from: eeguy on September 07, 2016, 01:18:36 amBecause it still sells well enough. Don't forget that, as big brands are concerned, the low end segment pretty much belongs to Keysight (as seen above Tek isn't worth considering, LeCroy's low end sucks, and Hameg/R&S low end stuff isn't as widely known and similar expensive as Keysight).QuoteCan't say but the low sample memory (which halves in certain situations) means the sample rate (and thus the usable frequency) will drop quickly on longer timebases.QuoteThe GW Instek GDS-2000A is pretty old, and has long been replaced by the GW Instek GDS-2000E which comes with 10Mpts memory. There are various users here and according to their reports it's a very nice scope, and unlike Siglent/Rigol it's also very mature.[quote[However, Keysight seems to be a better brand. Sure, but that is of little help if your measurements become limited by the tiny sample memory. And it's not that GW Instek is a nobody in the T&M market (they have been around for a very long time).Personally I'd go for a GDS-2000E over the Keysight DSOX2000A any day.QuoteThat depends on your requirements (keep in mind that 100MHz BW means 100MHz sine, not 100MHz non-sine like square or pulses).But should you go with the GDS-2000E then the 200MHz variant will still be cheaper than the 100Mhz DSOX2k.

author: JPortici
author_rank: Super Contributor
timestamp: September 07, 2016, 05:42:15 am
content: Quote from: Wuerstchenhund on September 02, 2016, 06:35:31 pmyou might have been referring to the TBS2000i actually use a TPS2014 daily at work (the battery powered, 4 isolated channel scopes) a 1054z at home and the UI on the tek is a lot smoother on that the rigol. That has become pretty annoying that if i only neet to look and make estimates i just use a tek7704AQuotesecondedQuotei have the same dilemma (iwaaaaaaanta lecroy -ehr, siglent rebadge?- but it's more probable i'll need the exotic serial decoding)

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 07, 2016, 09:42:45 am
content: Quote from: JPortici on September 07, 2016, 05:42:15 amNo, I was referring to the MDO3k/4k, DPO/MOD2k/3/4k/5k/7k/70k, and TDS5k/7k. Which not only are horribly slow scopes per se (weak architecture), they all share that the UI locks up when the scope is doing something processor-intensive. Which is silly, really (and not something I've seen on a Rigol).I haven't seen a TBS2000 in the wild but what can be seen from the videos it seems to have retained typical Tek annoyances.QuoteThat might well be but then the DS1054z is really the bottom of the barrel regarding scopes (it's only good because of i's very low price), plus the TBS2000 is a very simple scope which can't do anything complex anyways.QuoteWell, Tek certainly had a good hand for analog scopes.QuoteThe WS3k is not a rebadge. The hardware is a co-development of LeCroy and Siglent (which also acts as the manufacturer), and the software has been developed by LeCroy (Siglent can't touch it). Siglent is also allowed to sell the scope under its own name as SDS3000 in China but not outside.QuoteFair enough, but you pretty much have to pay for it through the nose.And considering the DSOX3kT's tiny 4Mpts memory (plus that in many cases it actually halves) I'd consider using some USB device (i.e. a Salae) for decoding exotic standards because it will capture much longer sequences than the DSOX3kT (where you also can't just manually drop the same rate to increase the acquisition time). If a USB device could be a viable way for you then get a WS3k + the Salae and still quite a lot of money.

author: Fungus
author_rank: Super Contributor
timestamp: September 07, 2016, 10:57:11 am
content: Quote from: eeguy on September 07, 2016, 01:18:36 am...something that an oscilloscope is totally unsuitable for.For that you need something like a multimeter with PC connection and some PC software to calculate the numbers. Probably two or three of them in fact.Even better: Get a power supply with logging ability and power your robot from that. It will tell you the overall consumption directly.You're in here worrying about 'bandwidth' and stuff but I get the feeling you're asking about screwdrivers when you really need a saw.

author: JPortici
author_rank: Super Contributor
timestamp: September 07, 2016, 11:05:14 am
content: Quote from: Wuerstchenhund on September 07, 2016, 09:42:45 amyes but earlier you wrote "Tek just came out with the new TPS2000"i was referring to this with the beginning of the postthe TBS is the new one, a small mistake that could arise confusionit would actually be nice if tek or possibly someone else made a new 4 chan isolated scope (with a decent amount of memory this time)but let's not derail the topic, the reason why and why not have already been discussed in the "what's missing on the market" topicyou are right on the lecroy!

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 07, 2016, 11:44:47 am
content: Quote from: JPortici on September 07, 2016, 11:05:14 amOh, yes, that should say "TBS2000" (a typo which has now been corrected).QuoteYes, it does, obviouslyQuoteAgree, most portable scopes are pretty dire in terms of memory (even that expensive R&S ScopeRider comes with 500kpts max, but on the upside it can do 2Mpts data logging and 12Mpts history, plus it's a 10bit scope). There's the Keysight U1620A with 2Mpts but that is 2ch only. Oh well...QuoteAgree.

author: eeguy
author_rank: Regular Contributor
timestamp: September 07, 2016, 12:39:44 pm
content: I am not sure if the Keysight DSOX2k Series can be connected to a computer via USB so that I can store the data real-time. If there is such a built-in function, do I still need to worry about the 1Mpts of memory limitation?

author: nfmax
author_rank: Super Contributor
timestamp: September 07, 2016, 12:45:57 pm
content: Yes, the X2000 series can be connected by USB to a PC. The connection library is a free download from Keysight, and I believe the free version of Benchvue lets you download and save data (if not, it's pretty easy to write a short Python program to do so). You are still restricted to the maximum of 1 MPts/channel (in single-shot mode), but these scopes do support segmented memory (option) which lets you partition the 1MPts between multiple trigger events. You cannot stream data in real-time over the USB connection - USB can't support the data rate, even if the scope firmware allowed it.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 07, 2016, 01:54:56 pm
content: Quote from: eeguy on September 07, 2016, 12:39:44 pmYes, it can connect to a computer, either via USB2 (built-in) or Ethernet (unlike with other scopes an optional feature on the DSOX2kA and DSOX3kA scopes, and not exactly a cheap one either). Neither allows the streaming of sampling data in real-time.

author: eeguy
author_rank: Regular Contributor
timestamp: September 08, 2016, 02:55:55 am
content: I guess if the scope can send the data to the PC via usb for later data analysis, that might be find. In this case, what memory size do you recommend?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 08, 2016, 05:04:50 am
content: Quote from: eeguy on September 08, 2016, 02:55:55 amThat very much depends on what you want to do, really. If you want to stream data to a PC then a PicoScope might be the better option.It looks like you don't really know what you need. "Robotic research' is such a wide field that goes from what essentially are tiny remote-controlled vehicles to highly complex autonomous systems that can move even in rugged terrain, so without you giving further details what exactly it is you want to do it's hard to recommend something appropriate.As others said, if you want to measure power draw of a motor then a scope isn't the right tool. If you however work on control systems then depending on the complexity of your robot you might want a decent mid-range scope with large memory and tools that help you find and isolate glitches.Post-processing acquisition data on a PC is usually done for stuff like signal analysis but in robotics signals usually aren't complex so I'm not sure why you would want to push them to a PC.It also helps to narrow down a budget for the scope but be warned that depending on what you want to do that may or may not be enough. In the latter case you should also consider 2nd hand (used) instruments.

author: rstofer
author_rank: Super Contributor
timestamp: September 08, 2016, 06:31:44 am
content: The Keysight DSO2014A (100 MHz, 4 Channels) starts at $2400 and the options can run another $1200 so you wind up with a scope costing $3600 by the time it is useful. Right around 9 times the cost of the Rigol DS1054Z.The MSO2014A (100 MHz 4 Channels plus 8 Digital) is nearly $3200 plus options - or about 11 times the 1054Z by the time it does serial decoding. But the 1054Z doesn't have the MSO option. I can buy a logic analyzer if I really need one!I can do an awful lot of robotics stuff (or anything else) with the 1054Z. Now, true, my projects have never done the DARPA Challenge of autonomously crossing the desert but I would be willing to bet that the 1054Z can handle absolutely everything involved. And at 11% of the cost of the DSO2014A I wouldn't mind if it got full of sand!A little realism can be helpful. What are the real requirements? What is the budget? Is this a funded project or is it just for a hobby? Yes, if somebody else was paying, I might be willing to spend 11x as much of their money. If it's my money, well, I will get by with something I can actually afford.If you need blazing bandwidth, maybe a high bandwidth DSO simply costs too much and maybe storage isn't the only way to get the measurement. For a couple of hundred dollars, you can get a used Tek 485 which is a fairly trivial analog scope with 350 MHz bandwidth. Considering the lack of advanced features, the 485 probably wouldn't be the go-to scope but it's nice to have the bandwidth should it ever be necessary.I can see where the Keysight DSO2000X series can be considered 'entry level' when high end scopes are up in the $150k range. But in my world, I just couldn't justify spending that much money for a scope. This electronics thing is just one of several hobbies.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 09:44:22 am
content: Quote from: rstofer on September 08, 2016, 06:31:44 amMe too.And if it's data-logging you want then an oscilloscope seems like the wrong tool for the job. There's plenty of gadgets that will log voltage/current over time with a lot less effort than an oscilloscope. Plus you won't be tying up your most useful tool doing mundane tasks.

author: JPortici
author_rank: Super Contributor
timestamp: September 08, 2016, 10:53:10 am
content: Quote from: rstofer on September 08, 2016, 06:31:44 amTo you, and that's fine. Maybe not for the OP.I'd never use the 1054z for a day job.. infact i don't. The day i needed 4 chan SPI i brought my 1054 (I don't have 4 chan scopes with decoding at the workplace, no need) but it was so frustrating to use at the pace i have at work that i put it away about 10 minutes later and decoded by hand the data from a tek tps. it was faster that way.At home, for my hobby projects where i don't get paid to finish them in a reasonable amount of time, is okay. Almost fine.

author: rstofer
author_rank: Super Contributor
timestamp: September 08, 2016, 02:38:21 pm
content: Quote from: JPortici on September 08, 2016, 10:53:10 amAccording to the OP, this was for an educational institution - graduate school. Maybe they do have funding for something more refined. OTOH, it could wind up being a designated sacrificial instrument.All of my comments should be taken in the context of a hobby; I have never spent more than about a month practicing electronic engineering. My career revolved around electrical engineering - power, lighting, project management, that kind of stuff. Boring but financially beneficial.As to measuring power for various motors, there is no sense in using a scope. It's the wrong tool for data logging. In fact, I would probably cobble together a high side current sense amplifier to measure current and another op amp to measure voltage and just use a uC with ADC capability. If a uC wasn't fast enough, I could just use an FPGA with the problem being where to store the data at the rate I would be collecting it.

author: Fungus
author_rank: Super Contributor
timestamp: September 08, 2016, 02:58:02 pm
content: Quote from: rstofer on September 08, 2016, 02:38:21 pmA motor is a big inductor. The current can't possibly change at high frequencies.

author: rstofer
author_rank: Super Contributor
timestamp: September 08, 2016, 05:02:07 pm
content: Quote from: Fungus on September 08, 2016, 02:58:02 pmThat's exactly right! I was thinking that even 1000 samples/sec would be more than adequate but I'm not on the cutting edge of whatever is going on. Certainly anything in the GS/s is overkill!Or, oversample the data at, say, 10 kHz and take some kind of average before storing the results.

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: September 08, 2016, 08:05:20 pm
content: Quote from: eeguy on August 04, 2016, 01:14:10 amMaybe consider national instruments hardware and software package over a scope for your app.

author: eeguy
author_rank: Regular Contributor
timestamp: September 08, 2016, 09:53:05 pm
content: I want to do sensory motor integration and motor control at home. Besides, I need a scope to test some circuits. As for the reason for data logging, I want to publish the data in academic reports. So, being able to store the data to a computer would be desirable. I guess I should not spend more than 3K. Of course, if paying a bit more makes a big different, I would consider it.

author: nctnico
author_rank: Super Contributor
timestamp: September 08, 2016, 10:01:51 pm
content: What exactly do you expect to get from logging? If you say reports then I assume graphs based on multiple measurements or screendumps. I usually produce graphs in reports the old fashioned way: take a sheet of paper, divide in columns, write down the measurement results and type everything into Excel. Ofcourse you can automate this but you have to weigh the amount of effort versus time saved first.

author: rstofer
author_rank: Super Contributor
timestamp: September 08, 2016, 10:21:51 pm
content: I would design the measurement capability into the individual drivers. The high side current sense amplifier and some kind of voltage measurement would be easy to add. In fact, I can see an I2C bus running around to the various drivers and interrogating ADCs. Maybe I would route a 'trigger' around such that all measurements are taken at the same time. In fact, I would just put a small uC on each driver which would already have a suitable ADC.Suppose I did put extra hardware, including an uC at each driver. I could do something really neat by adding RS485 and having a multi-master network. Doing this would allow me to interact with the uCs with some kind of RS485 driver on any PC USB bus.Having the data readily available opens up the opportunity for logging and reporting.I'm not sure how this thing would go because I have no idea about what is being built. I could see WiFi as a communication strategy, all I would need is a TCP connection to grab the data.A scope would be a necessary tool for some part of the project but not for data logging.

author: saturation
author_rank: Super Contributor
timestamp: September 08, 2016, 10:37:10 pm
content: You can get data logging power meters from the same sources I mentioned. Also most Agilent DMM's can log as well as send log data via bluetooth, even its low cost ones. The GWInstek 1054B has a logging app included.The real question you need ask is is how much time of log data will you collect, what accuracy do you need, digits, is it data points or waveforms? If unlimited or undefined you'll need it logged to a PC, which has buku memory via its hard drive for data or full waveforms. Many stand alone loggers have limited local memory, is that long enough for your purpose?E.g. the 1054B has a logger for ~ 100 hours [ i.e., 4 continuous days] of waveforms, not just data points.In the USA, not as popular as the Rigol, it available discounted from Tequipment, just ask for a price lower than listed.Quote from: eeguy on September 08, 2016, 09:53:05 pm

author: JPortici
author_rank: Super Contributor
timestamp: September 09, 2016, 06:35:13 am
content: Quote from: rstofer on September 08, 2016, 10:21:51 pmi would do this as well. you need it anyway if you don't want to bother with current probes and/or lots of wires hanging around, which also get quiclky very impractical. how then they send the data to the computer or other unit is up to you

author: Fungus
author_rank: Super Contributor
timestamp: September 09, 2016, 08:33:34 am
content: Quote from: rstofer on September 08, 2016, 10:21:51 pmMe too. Not all motors will have equal consumption (it depends on load) so looking at them in groups won't be very useful.Each motor should probably have a small microcontroller attached to it for position control. You can add in power measurement as well.Network them all together and you have full monitoring. No need for an oscilloscope.The oscilloscope will be used for debugging the communications network, a DS1054Z is perfectly capable of that.

author: rstofer
author_rank: Super Contributor
timestamp: September 09, 2016, 06:40:00 pm
content: Of all the ways to communicate between a PC and the world, a USB HID device is about the easiest to implement. Among many other boards, the Teensy boards can do this nicely:https://www.pjrc.com/teensy/rawhid.htmlhttps://www.pjrc.com/store/teensy32.htmlI'll leave reading through the 1100 page manual to others but it appears that the chip has 16 bit ADCs:https://www.pjrc.com/teensy/K20P64M72SF1RM.pdfI used a much older Teensy and the HID interface to tie physical knobs and dials to Microsoft Flight Simulator so coding for HID must have been pretty easy.It would be worth verifying which versions of Teensy support the RAW HID code.

author: eeguy
author_rank: Regular Contributor
timestamp: September 11, 2016, 02:01:18 am
content: For general purpose testing of electronic circuits, sensors, motor controllers and motors, would you recommend the DSOX2012A (100MHz, 1Mpts, 2GSa/s), 2022A (200MHz, 1Mpts, 2GSa/s) or the 3012T (100MHz, 4Mpts, 5GSa/s)? Not sure if it is worth to spend that much money on the 3012T.How is the quality of Rigol and GW Instek scopes? Tektronix was very famous many years ago but it seems that their scopes are not popular anymore. What is wrong with Tektronix scopes?

author: TheSteve
author_rank: Unknown
timestamp: September 11, 2016, 02:26:22 am
content: If you're going to up your budget how about a used DSOX3014A from ebay etc?

author: nctnico
author_rank: Super Contributor
timestamp: September 11, 2016, 09:34:53 am
content: Quote from: eeguy on September 11, 2016, 02:01:18 amThe build quality of Rigol and GW Instek is just fine.Tektronix used to make great scopes but their current offerings (not just their scopes!) are very poor value for money and it seems they are only selling to universities and schools nowadays. I wouldn't be surprised if Tektronix' T&M division gets bought by another T&M manufacturer because the brand name still has value.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 11, 2016, 10:54:44 am
content: Quote from: eeguy on September 11, 2016, 02:01:18 amThat is difficult to say without knowing what exactly you will be working on. For very basic tasks the DSOX2k is fine, but it comes with very small memory and comes with some limitations (IIRC serial decode only works on analog channels) that make it less suitable for more complex tasks. It's not a bad scope per se but these days I'd rather get a GW Instek GDS-2000E which has more memory.And as said before the DSOX3kT is very expensive for a scope with just 4Mpts of memory. The much better alternative is the LeCroy WaveSurfer 3000 but I guess you have reasons for not considering it.QuoteGW Instek has been around for a long time, like Hameg (now owned by R&S) they pretty much foxus on entry-level instruments. The build quality has always been good from what I know. Support had been a bit spotty but that was probably 10 years ago, and since then they have made lots of improvements and now are very responsive.Rigol, well, I think the build quality is good. What would concern me more is that they are apparently unable to properly design their hardware (search for 'Project Yaigol'). Also, pretty much all their products come to market in a bug-infested state, and it can take a while until the worst ones get fixed (and some are probably never fixed, like ETS on the DSO6000). Rigol is cheap, the scopes are widespread amongst hobbyists, and they can be hacked.QuoteAs I already said above, Tek was famous when analog scopes were still a thing, and Tek has made the best analog scopes that were ever made, sometimes using some very sophisticated technology for back then. But Tektronix never really made the mental jump to digital, they would have gladly continued to make analog scopes if the market and their customer hadn't forced them to make digital ones. Unfortunately that is visible in most of their DSOs, which are average at best and in many cases a pain to use. There's very litte innovation in Tek scopes aside from the price, for which you get slow hardware with an awful UI that was designed by someone who must have hated humans. New scope models often aren't new scope models but simply a re-hash of their older scopes. Support has also taken a steep decline.The equivalent to Tektronix for digital scopes is LeCroy, which are the ones who really push DSO technology forward and who do a lot of stuff you can't get anywhere else, not even from Keysight.

author: Fungus
author_rank: Super Contributor
timestamp: September 11, 2016, 02:23:31 pm
content: Quote from: Wuerstchenhund on September 11, 2016, 10:54:44 amSummary: Rigol copied/pasted a less-than-ideal design for the main oscillator. It worked well enough that there was no effect on any measurements in the lab... except in one extreme case which took the world a few months to find after launch.Rigol responded with a firmware patch and the effect vanished. You could replace the 'broken' oscillator with a perfect one and there would beliterally no difference at all. Not on screen, not in any measurements.Do GW-Instek, etc., have similar internal "faults"? We'll probably never know because they don't sell enough units to have armies of people pulling them apart and reverse engineering them.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 11, 2016, 05:09:26 pm
content: Quote from: Fungus on September 11, 2016, 02:23:31 pmI don't know if that has any effect on any measurements, but copying a design they obviously don't understand it is a very stupid error to make and doesn't exactly instill confidence in Rigol's overall design competence.On the other side most Rigol gear is reasonably cheap which might compensate for that. But people should make their own mind up as to how much weight they put into the individual properties and issues.QuoteI seriously doubt that GW Instek has made similar mistakes in their design (considering that they make test gear for over 40 years now), and the big brands certainly even less so.

author: Fungus
author_rank: Super Contributor
timestamp: September 11, 2016, 05:13:53 pm
content: Quote from: Wuerstchenhund on September 11, 2016, 05:09:26 pmYou're the one telling people to read the "Yaigol" thread where all this is investigated. Haven't you read it yourself?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 11, 2016, 05:54:44 pm
content: Quote from: Fungus on September 11, 2016, 05:13:53 pmI'm telling people to read that so that they have all the facts so they can make a better informed decision.Since I don't own any Rigol gear any longer I haven't read all of it.

author: nctnico
author_rank: Super Contributor
timestamp: September 11, 2016, 06:20:25 pm
content: Quote from: blueskull on September 11, 2016, 06:14:57 pmWho said this forum is about DIY only? Lots of professionals here who need test equipment to make a living. I'd love to see more reviews of equipment made by other manufacturers than Keysight, Rigol or Siglent because there are many hidden gems to be found which have much better value for money (new or used) or have features lacking on other equipment.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 11, 2016, 07:23:01 pm
content: Quote from: blueskull on September 11, 2016, 06:14:57 pmWhy?QuoteI doubt LeCroy would pay me anywhere near my standard rate.QuoteSorry but that it nonsense. There are lots of professionals here as well, probably because there aren't many international EE forums of a similar size. And for a large part its the professionals that give advice and support to the hobbyists in this forum.QuoteThe reason LeCroy isn't common amongst hobbyists is that for years they pretty much only served the mmid-range and high-end market, which has pretty much their place all along. LeCroy was and still makes the most advanced scopes on the market. You find them in lots of cutting edge areas where any other scope doesn't cut it. Simple as that. On the down-side, they never really cared much about the entry-level (and still only sell rebadges from Iwatsu and Siglent there), so it's no surprise that the average hobbyist doesn't know them. But then, many hobbyists don't even know that there are other companies than HPAK and Tektronix making scopes, so that isn't really saying much.On the other hand, many professional EEs and scientists know LeCroy scopes, and there's also a sizeable amount of individuals who got one of the older scopes and pretty much got hooked.So I'm not sure what you wat to say. If you suggest that Rigol and Keysight shall be the only brands ever mentioned in this forum then I doubt that this will work. If you want a Keysight-only forum then Keysight already has one.In Germany there's a saying:"Fresst Scheisse, Millionen Fliegen koennen nicht irren"("Eat shit, millions of flies can't be wrong!"). It should tell you that just because everyone follows the mainstream that this is actually the best solution. Sometimes it pays off to consider alternatives.

author: Fungus
author_rank: Super Contributor
timestamp: September 11, 2016, 07:42:39 pm
content: Quote from: Wuerstchenhund on September 11, 2016, 07:23:01 pmIt exists in English as well.The point is that the endless Rigol bashing (and pointing people to the "Yaigol" thread is 100% bashing - you know perfectly well that the clock problem doesn't have any measurable effect) is totally out of perspective.The Rigol DS1054Z has its flawsbut:a) It only costs $400andb) You have to pay $1200+ to really get anything better.Yes, there's a couple of 'scopes around the $800 mark that can do certain things better but you'll lose out badly on bandwidth or number of channels or something else. If you have a very specific need you might be better off with one of those but for an all-round 'scope that beats the (hacked) DS1054Z you need to pay $1200+. Even then it will only beat it on a few features, to really thrash the DS1054Z in all departments with a non-Rigol scope you might need to pay $2000+.$800-$1000 difference buys an awful lot of other kit if you're spending your own money on test gear. It seems childish to point people to the "Yaigol" thread just because you feel the Rigol is imperfect.

author: MotoDog
author_rank: Contributor
timestamp: September 11, 2016, 08:05:10 pm
content: I have quite a few scopes. 2 HP, one with LA. Some older Teks. Along with HP Function and RF Generators.And a Rigol Spectrum Analyser.I just bought a Rigol scope ( the 4 Channel 50 MHz Z Model) on eBay 6 mo ago. Still have 30 hours of free Options running.I love it. Yes, the controls will cause you extra bump or settings, and it does not remember setting when you turn it off.Tiny Scope, lots of Options and Channels!Gee, I paid about $360 for it, not used but a few hours. You can find ways to open options on the internet.My biggest complaint, is seeing the screen. There really are more measurement options than I would want. Start putting themon the screen and for my old eyes (71), I WISH it had a BIGGER Screen. Please Rigol make the same thing with a 12-14" display for us old guys!. Bigger Text on the screen, and a little bigger traces?Did I mention, you get 4 Probes with it TOO! It is running as 100 Mhz now!I have had and still have one PC Oscilloscope. I like the hardware and the Price, but the Software was not very good on them.The Chinese ones for 60$ work good, but I hated the operating software and complete lack of triggering options.I will never buy another.The Rigol is actually TOO Small. Takes no room on my workbench, I keep 2 probes on it at all times hung up on a cup hook tokeep away from the soldering iron stand!You also can find DISCOUNTS for students! Check Saileg or others?Mike

author: bitseeker
author_rank: Super Contributor
timestamp: September 11, 2016, 11:17:11 pm
content: Quote from: MotoDog on September 11, 2016, 08:05:10 pmPerhaps give a large Fresnel lens a try. It won't be spectacular, but it'll be larger.QuoteAnd if you're not a student, Saelig and TEquipment have EEVBlog discounts. Search the forum for the appropriate threads.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 12, 2016, 05:19:41 am
content: Quote from: Fungus on September 11, 2016, 07:42:39 pmAgain, I did not say that the design flaw has any impact on measurements (and no, I don't know that, since again I don't have any Rigol gear any more and I never had a scope, but I do assume it's not a problem in most situations since apparently Rigol has plastered it over through a firmware update). Still, like it or not the design flaw does exists, and I see no reason why people shouldn't be aware of it so they can make their own decision.I assume you'd prefer that this was kept under the rug, never to be mentioned again?QuoteOnce again, you're barking up the wrong tree here, as I fully agree that the DS1054z is a great bargain at its price. That isn't the question.QuoteThat is certainly true. However, not everywhere is the lowest possible price the most important factor, and while the DS1054z is good for a lot of basic measurements it's still a very basic scope (like pretty much all Rigols up to the DS6000), and there are many tasks where that isn't enough. The question is if what the OP wants to do can be achieved with a cheap Rigol, but so far I don't think we have enough details to say for sure. Robotics is a huge field and not just limited to motors, actuators and power controllers so until here everything is more or less guesswork.QuoteThat isn't a slight imperfection, it's a pretty big mess-up from a design perspective. Now you might not care how your test gear works but many professionals do. And then it doesn't really matter that the problem has been plastered over by firmware or that the scope is cheap, if they can't even design an oscillator properly then I really have zero trust in that instrument. I accept that for many hobbyists that isn't an issue, but as I said people should make up their own mind and for that they need all information, not just the positives.The real question is why you're so keen to suppress the existence of the Yaigol thread?

author: tautech
author_rank: Super Contributor
timestamp: September 12, 2016, 05:56:23 am
content: Quote from: Wuerstchenhund on September 12, 2016, 05:19:41 amBecause there's so much more in there that some don't want to get out.https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/msg890964/#msg890964From the attached PDF:In DS2000 oscilloscope not only the PLL power regulator oscillates,all 1117 type LDO voltage regulatorsoscillatein factory scopes.Quote from: Wuerstchenhund on September 11, 2016, 05:54:44 pmYou should.The crux of it all is in Bud's first few posts and particularly the attachments.Bud's work will never be dismissed IMHO as he and MarkL initially bought the PLL issue to this forums attention, Dave then did a vid on this F***úp and pressure was then bought on Rigol to place a bandaid over the problem.History that can't be overlooked as much as some might want you too.

author: JPortici
author_rank: Super Contributor
timestamp: September 12, 2016, 06:36:40 am
content: Quote from: MotoDog on September 11, 2016, 08:05:10 pmTrue, at the end of the day 400 for a set of okay probes is a good bargain, i like 'em(really)

author: Karel
author_rank: Super Contributor
timestamp: September 12, 2016, 06:39:20 am
content: Quote from: tautech on September 12, 2016, 05:56:23 amLike this for example?Don't buy anything from Siglent if you are not sure you don't want to sell it on Ebay later...https://www.eevblog.com/forum/testgear/siglent-they-filed-a-'wrongful-trademark-claim'/

author: tautech
author_rank: Super Contributor
timestamp: September 12, 2016, 07:22:16 am
content: Quote from: Karel on September 12, 2016, 06:39:20 amI knew casting a sprat would catch a mackerel.Have we seen any Rigol HW revisions that might indicate all these design issues might have been addressed ?Have we seen any representation from Rigol in Dave's lab explaining they have?Have we seen Rigol involved in open discussion giving reasons for their design errors and steps taken to ensure they won't be repeated ?The Siglent issue you raise Karel has been fully and openly addressed on this forum all the way to the CEO of Siglent and it is surely a pity that Rigol are not also so open so that their matters can be put to past history too.

author: eeguy
author_rank: Regular Contributor
timestamp: September 12, 2016, 01:08:39 pm
content: Thank you for the comments. Most likely I go for either GW Instek or Keysight. Are they quiet? I cannot stand noisy equipment. Can they also be hacked with software enabled freely and easily to get more functions and higher specs without the company knowing? In the case of GDS, some scopes have an 'A' ending while others have an 'E' ending. For example, 2204A vs. 2204E. 2204E seems to have 10M/ch of recording length while the 2204A only seem to have 2M/ch. 2204E is also less expensive. I asked GW Instek via chat but no reply even chat is online.The 2104A has a rise time of 3.5ns while the 2204A, 2204E and 2304A has a rise time of 1.17ns. In general, is 3.5ns fast enough?For GDS, I consider 2102A, 2104A, 2204A and 2204E. Cannot find GDS-2000E on their website. Which is the latest and greatest? I need external trigger function (e.g. press a button and different devices start working) and usb storage of data for plotting in EXCEL or Matlab. Experiments last about 10-30 seconds, no more than a minute or two.

author: Fungus
author_rank: Super Contributor
timestamp: September 12, 2016, 01:30:14 pm
content: Quote from: eeguy on September 12, 2016, 01:08:39 pmNo.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 12, 2016, 02:45:02 pm
content: Quote from: eeguy on September 12, 2016, 01:08:39 pmSimple. 'A' was the previous generation, the current one is the 'E'.QuoteFrankly, I get the very strong impression that you have actually no idea what you want or what you need. What's more frightening is that it looks you don't even seem to know what exactly you want to do (motors and actuators actually make only for a small part of robotics). Which simply makes it impossible to give you a proper recommendation.Considering all that, maybe the best option for you is really to get a Rigol DS1054z and use that until you know the basics and understand better what you want to do and what you need.

author: Fungus
author_rank: Super Contributor
timestamp: September 12, 2016, 03:35:36 pm
content: Quote from: eeguy on September 12, 2016, 01:08:39 pmFast enough for what?Basically that rise time is just the 'scope's bandwidth written another way.3.5ns is 100MHz.Quote from: eeguy on September 12, 2016, 01:08:39 pmAnd that's 200MHz.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2016, 03:45:45 pm
content: Quote from: Wuerstchenhund on September 12, 2016, 02:45:02 pmExactly! The rise times mentioned above are simply indicative of the scope bandwidth. Faster rise time, more bandwidth hence the difference in model numbers.One advantage to the DS1054Z is that, even used, it will always be worth $300 or so (based on $400 new). So use it until it becomes a hindrance (if it ever does) and then either sell it to get funds for a more expensive model or designate it as a sacrificial scope for noobs.Yes, better scopes are a treat! More bandwidth is always the right answer and more memory depth, triggering options, decoding options, channels and any other feature I overlooked are always better. They may not be necessary but they're cool to talk about.The hacked DS1054Z is a decent 100 MHz scope. But a 100 MHz square wave is going to look terribly sinusoidal. If you want to actually display a 100 MHz square wave, you probably need at least a 500 MHz scope (give or take). So, the 1054 is going to be able to display a 20 MHz square wave pretty well and that's probably good enough. Most of the processors we use run a lot faster but their IO pins don't toggle at anywhere near the clock rate.In my corner of the sandbox, four channels is more important than increased bandwidth. If I run out of bandwidth, I'll upgrade. In the meantime, I haven't found anything I can't do with the DS1054Z. But it's early days...

author: eeguy
author_rank: Regular Contributor
timestamp: September 12, 2016, 03:50:36 pm
content: Quote from: Wuerstchenhund on September 12, 2016, 02:45:02 pmThanks. So, E is more recent and cheaper?I always got access to the expensive scopes at well funded research labs. I only used them. I did not have to know the detailed specifications of the scopes. Now I have to buy my own using my own money.I just checked the specs of a scope I used many years ago. It had 4 channels, 200MS/s sampling rate at 2 channels and 100Ms/s at 4 channels, equivalent sampling 20Gs/s, sensitivity 1mV/div to 5V/div, 5ns/div to 50 s/div, sweep time of 120k word (2 channels), 56k word (4 channels). 2M word max recording length, 150MHz.

author: eeguy
author_rank: Regular Contributor
timestamp: September 12, 2016, 04:17:28 pm
content: Quote from: blueskull on September 12, 2016, 04:03:22 pmI plan to make robots and some electronic circuits. A scope is needed during the testing and diagnostic stages. I just try to get a general purpose, future proof scope. I don't think I will need more than 200MHz. I am more concerned about sampling rate and recording length. I guess one good thing about the Agilent scopes is that they can be upgraded as needed.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2016, 04:34:30 pm
content: Bandwith (in Hz) = 0.35 / RiseTime (in seconds) so if the Rise Time is 3.5 ns, we have 0.35 / 0.0000000035 or 100,000,000 Hz. A 100 MHz scope should have a rise time of 3.5 ns. Give or take...I just measured the rise time of an Arduino Uno PWM signal as 4.0 ns. Some part of that is my scope (3.5 ns) and some of it is my crappy probe (just a garden variety 100 MHz probe, not Rigol probes) so, even after getting the magic rise time measurement on my scope, I have no idea where the Arduino rise time really comes out. I'm actually surprised it is that fast!I should buy one decent 500 MHz probe to eliminate probe effects from the measurements.OR, I could be a little more practical and ask the question: "Does 4 billionths of a second make any difference to my application?". Not likely!

author: Fungus
author_rank: Super Contributor
timestamp: September 12, 2016, 04:36:55 pm
content: Quote from: eeguy on September 12, 2016, 01:08:39 pmQuieter than a DS1054Z, yes.Quote from: eeguy on September 12, 2016, 01:08:39 pmI wouldn't go for 2 channels so that means the cheapest option is the 2104A at $1450 (give or take).You probably need serial decoding for real robotics work. The Instek "logic analyser" option costs $550 (give or take).That means you're looking at about $2000 for something to do a job that could be done perfectly well with a DS1054Z.$1600 for a quieter fan? That's up to you.I know some forum members who fitted a much quieter fan to their DS1054Z for <$20.(Yes, I know a GDS2104A will do more than a Rigol DS1054Z, I'm referring to the feature set you're probably going to use in 'robotics').

author: Fungus
author_rank: Super Contributor
timestamp: September 12, 2016, 04:40:53 pm
content: Quote from: rstofer on September 12, 2016, 04:34:30 pmIf it's more than your scope's rise time then most of it will be from the signal. It's when you're seeing exactly the scope's rise time that you realize you need more bandwidth.Quote from: rstofer on September 12, 2016, 04:34:30 pmNormal probes are usually good for a lot more then 100Mhz. 300MHz(ish) is where the bad stuff starts to happen. There have been a few threads on this.

author: nctnico
author_rank: Super Contributor
timestamp: September 12, 2016, 04:48:35 pm
content: At least the GDS-2000E series has input filtering. I think this is going to be very helpfull for an upcoming project to see what signals are hidden in a PWM and AM modulated signal.

author: saturation
author_rank: Super Contributor
timestamp: September 12, 2016, 05:04:49 pm
content: Most any reputable >= 100 MHz scope will meet your needs, its a question of bang for buck and the right bandwidth.For example the 50 MHz Rigol 1054Z or Instek 1054B will do real time sampling of 1Gs/s 1CH, 500Ms/s 2 CH 250Ms/s at 3 or 4 CH. Equivalent sampling is no longer specified in newer DSOs as it worked only on truly repetitive signals. Vertical sensitivity is the same or better and the old measure of 'word' for record length is replaced by megapoints "Mpts".Both low cost DSO offer more record length memory than mentioned below, and for the Rigol more bandwidth and memory with a successful hack.Quote from: eeguy on September 12, 2016, 03:50:36 pm

author: Fungus
author_rank: Super Contributor
timestamp: September 12, 2016, 05:22:54 pm
content: Quote from: saturation on September 12, 2016, 05:04:49 pmFTFY.

author: tautech
author_rank: Super Contributor
timestamp: September 12, 2016, 08:00:59 pm
content: Quote from: eeguy on September 12, 2016, 01:08:39 pmWell you're going to have to trust somebody's word or really do your homework.Most modern scopes have a fan and the more functionality that's inbuilt requires more computation and therefore more cooling. Period.One thing you might want to consider is the size of any fan, larger ones tend to run at lower RPM's and therefore produce less noise.QuoteGood luck with that.In the years that I've sold scopes there have been so many advances in entry level DSO's but at the end of the day you have to work out whatfeaturesare of most importance to you.There's an ongoing battle to add more features to capture market share so who's to say what feature/s might be included in models 6 months out that you won't wish to have too.Your budget will have an influence on longevity for other than mid and high range equipment most have been built to a price and that includes design, component and build quality and feature set.

author: nctnico
author_rank: Super Contributor
timestamp: September 12, 2016, 08:07:03 pm
content: Quote from: eeguy on September 12, 2016, 04:17:28 pmForget about that. How long do you drive around in the same car? Now let me tell you test equipment depreciates even faster than a car.

author: rstofer
author_rank: Super Contributor
timestamp: September 12, 2016, 10:13:12 pm
content: Quote from: blueskull on September 12, 2016, 04:03:22 pmI got involved with recommending a used Tektronix on another thread a couple of weeks ago. What a mistake! The buyer got burned with a scope that doesn't function properly. I felt really bad about promoting the idea.I got lucky buying a Tek 485 on eBay but I'm going to stop recommending that idea. Unless they are prepared to write off the cost immediately, I now suggest they avoid used scopes.So, yesterday I had to troubleshoot the drivers on my CNC mill out in the garage. Which scope did I take? The Tek 485, not the Rigol DS1054Z. The Tek will stand on the floor, I don't need to know any more than the fact that the direction signal changes and the step signal pulses. Just show me a wiggly line, I don't need details.Sometimes old school is entirely adequate. Preferred, even!

author: rstofer
author_rank: Super Contributor
timestamp: September 13, 2016, 12:38:21 am
content: Quote from: blueskull on September 12, 2016, 10:45:08 pmTrue enough but almost any of the used analog scopes will be a good deal older. A decent DSO might be a good buy on the used market but I haven't priced them. At some point I want a warranty and then I turn around and void the warranty by replacing one of the switches. Duh...That's another nice thing about the DS1054Z: If it doesn't work out, I'm not out a lot of money. So far, I'm liking the scope. It does so much more than my Tek 485 (except bandwidth).

author: Faith
author_rank: Unknown
timestamp: September 13, 2016, 03:57:47 am
content: Quote from: nctnico on September 12, 2016, 08:07:03 pmYep the speed of the depreciation can be quite funny at times.Just saw a brand new and unopened Keysight MSOX3104T which was manufactured just three months ago sell on eBay for around five grand when the list price is about three times that amount.Makes it really difficult to justify buying new.

author: Faith
author_rank: Unknown
timestamp: September 13, 2016, 04:13:50 am
content: Quote from: blueskull on September 13, 2016, 04:04:44 amWow! How'd you manage that if I may ask? The options in particular is what interests me the most, since I usually find it harder to find fully licensed units.

author: Faith
author_rank: Unknown
timestamp: September 13, 2016, 04:25:32 am
content: Quote from: blueskull on September 13, 2016, 04:18:12 amAhh should have guessed. Pretty much every time I see a MSOX3104T on sale it was also acquired from Scope Month.That must have been quite an exciting drive :pCongrats!~

author: Fungus
author_rank: Super Contributor
timestamp: September 15, 2016, 09:17:32 am
content: Quote from: eeguy on August 30, 2016, 12:14:28 pmYes - latest firmware has sorted that.

author: eeguy
author_rank: Regular Contributor
timestamp: October 04, 2016, 02:01:23 pm
content: As far as I recall, somebody in the forum mentioned that for Keysight oscilloscopes, the seller might be able to enable more functions for free since they are all software based. Am I correct? What about the GDS-2204E? If they can only enable a few functions, what functions would be good to get?

author: nctnico
author_rank: Super Contributor
timestamp: October 04, 2016, 02:10:31 pm
content: There are no software options on the GDS2000E series so no upgrade hacks possible. Also I strongly doubt any Keysight reseller will enable options 'for free' unless there is a promotion going on. Remember the Keysight video where they put one of their scopes on a BBQ? Well they are going to use that same BBQ for any reseller who dares to sell their equipment hacked

author: rstofer
author_rank: Super Contributor
timestamp: October 04, 2016, 05:04:05 pm
content: Quote from: eeguy on October 04, 2016, 02:01:23 pmApparently, decoding is a standard feature for the GDS-2204E. I couldn't find anything that indicates that decoding is an extra-cost item.Unless there is a promotion, like the current MSO for DSO pricing, I wouldn't expect Keysight to do much of anything for the buyer of one oscilloscope. Buy a hundred or perhaps even as few as a dozen and they might talk. One scope? Not much chance...http://www.keysight.com/main/facet.jspx?cid=x2015004&pageMode=SO&cc=US&lc=eng&cmpid=20801

author: eeguy
author_rank: Regular Contributor
timestamp: October 04, 2016, 06:41:14 pm
content: Quote from: rstofer on October 04, 2016, 05:04:05 pmYes they mentioned about the MSO for DSO price but I am going to use a Logic Analyzer, I would probably buy an usb one. Do they often have promotion one after the other? If MSO is not important to me, perhaps I wait and see if they have a 200MHz or 300MHz for 100MHz price or 4 channels for 2 channels price?