Which lathe (err... Scope) Rigol

[PekkaNF]

Hi my name is Pekka and I am an electrical engineer

I know that questions like which is best/whatever for first lathe/scope questions are plentifull and hard to answer, but it took me four lathes to learn something on them, and I'm on my third scope and sill know nothing.....


I actullay never done any real electrical design or work, went to work on paper machine insdustry, which had some demand for electrical engineers.

I did a whole lot of study and hobby stuff on electronics lab in the university and spent time with quality instruments, most of them were Tektronix and such.

Hobbyist had no money to buy such stuff. I had 10MHz British made "transitor" scope and later 20MHz Philips tube scope, until I bought Rigol DS1052E 2CH 50 MHz scope.

To my opinion DS1052E is the firts passable scope I owned, but it has some quirks and features that are not exactly show stoppers, but still rather annoying.

1: Lack of 50 ohm input. In priciple no problem: just use 50 ohm. trough termination, but in reallity question is more complex.
True 50 ohm scope inputs seem to be better enginered and have less noise. Often, also sensitivity is better.

Why such a fixation on 50 ohm? I like to build my own probes. 50 Ohm transmission line is the only way to go on hobby planet. It is true, that it's not often really requred under 100-200MHz...and it is limited to low voltage levels - you don't want check thermal capacity of the internal 50 termination.


2: relating to #1, adjustable probe attenuation would be nice. My current scope has pretty much all standard ones, but it's missing 1:20 and no probe DC voltage calbration. Or least I cant't find it.


3: Ergometrics is not the best for me. I learned analog scopes, Gain was always over CH BNC and time scale on extreme right. Don't swap brake and gas on my car!  I'm still reaching wron dials. Also the main menu dial ridiculously small and feel is "cheap". I can use the user interface, but "flow" is not natural...press CH1, press button at the side of the screen...reach menu dial, jog menu, press dial, press dial another time...

Also display is rather small, sometimes I'm squinting numbers and thinkking is that comma or dust...I actually checed my tail once nearly two hours, before I figured I had interpreted one value 10x wrong and it was not probe attenuation.

4: Amplifier sensitivity...could be better. I keep on bumpping on low limit all the time. 8 bit DAC and noise does not improve readability.

5: bit more BW would be nice. All low price scopes seem to have max 1 Gs/s, so 100/200MHz nominal max. sine BW is in cards.

Here used scopes are not that common and good used ones (even alanog ones) have unrealistc prices.

My plan "B" is bring older TEK from USA following year, when I'll visit my friends.

But now I have grown into digital scopes and they have benefits.

I have been eyeballing two new options:

A) Rigol DS1054Z 50 MHz 4CH
https://www.batronix.com/shop/oscilloscopes/Rigol-DS1054Z.html

Price is right, dispaly is bigger and it has two channels more (alhough each channel will lower sampling speed and memory).

Ergometrics appears better on youtube videos and it has finer range on probe attennuation settings. But on paper, it is not much of an upgrade.


B) Rigol DS2102E 100MHz 2CH
https://www.batronix.com/shop/oscilloscopes/Rigol-DS2102E.html

Price is larger, but it has 50 ohm input and least on paper better input sensitivity....but it does not look like I would be getting whole lot more scope....if I read specks carefully.

I have this: DS1052E
Analog digital converter (A/D)    8 bits, make sampling on both channels synchronously.
Sensitivity range (V/div)    2 mV/Div to 10 V/Div.
Displacement range    ±10 Div. (2 mV - 10 V)
Time base    5 ns/Div. to 50 s/Div. (Steps 1 - 2 - 5)


A) Rigol DS1054Z 50 MHz 4CH
Analog digital converter (A/D)    8 Bit
Sensitivity range (V/div)    1mV/div bis 10 V/div
Offset range    1mV/div bis 10 V/div
Time base    5 ns/div bis 50 s/div


B Rigol DS2102E 100MHz 2CH
Analog digital converter (A/D) 12 Bit at ≥ 5 µs/div, 8 Bit at ≤ 2 µs/div
Sensitivity range (V/div)    500 µV/div to 5 V/div
Offset range    500 µV/div to 10 V/div
same DS indicates this cope as 8 bit, where does those extra bits come from?


However Data Sheet/Vertical Scale
When the input impedance is 50 Ω: 500 μV/div to 1 V/div
When the input impedance is 1 MΩ: 500 μV/div to 10 V/div
Note[3]: 500 μV/div is a magnification of 1 mV/div. When calculating the DC Gain Accuracy, the full scale should be considered as 8 mV (calculated based on 1 mV/div).

So, I'm not getting as much more sensitivy that I might understand from casual reading..

My question is that how much more usefull is 4ch vs. higher BW

200MHz 4CH and 50 ohm option on termination will drive price up.

I did consider entry level "Brand" scopes, but looks like inthe end I'm getting Rigol with less options and higher price, only difference being name on the enclosure.

Pekka

[eskoilola]

First You have to think what You will be measuring. Is it separate events or something that is repetitive (cyclic) or both. This determines whether You need a memory scope or just an ordinary real-time scope.

The memory scopes are nice but since those have to store their data somehow those have a ADC which comes with it's implications. One just cannot see beyond their BW. In an analog scope it is possible to see "hairs" and stuff even when the BW was long gone. Further more the display is not a CRT but merely a computer display so one actually cannot bypass the ADC even if one wants to do so.

I have two scopes. One is a dinosaur (Tektronix ... something) and the other is a HP memory scope with 8 channels and what not. It is on the edge of being a logic analyzer. It is very nice device on measuring separate events like seeing what is there really on the MODBUS.

Another thing You should be aware of is the BW. In my case 100MHz for the dinosaur is enough. It has 4 identical channels and all sorts of triggering options between those. Usually I find myself using the first channel. I am pretty sure I have never used all four at the same time. The triggering on a Tektronix dinosaur can lock beyond the 100MHz ... I have succesfully locked on 270MHz but that was a tad fiddly to do.

I think the minimum requirement for sensitivity is 1mV/division. Never needed less than that.

I think the IMPEDANCE of the inputs in all of my devices is 50 ohms. This does NOT mean that there is a 50 ohm resistor somewhere. Indeed, if I would measure the resistance on my straight probe it would probably be somewhere in the vicinity of one megaohm. The noise level in my old dinosaur is low enough to not to be seen when there are no probes connected. When the probe is there some noise can be seen as the probe is picking up all the interference in the air. If that would be a "true" 50 ohm resistive probe then that interference would not be seen.

[PK]

I agree, scopes now come in flavors and it really does come down to what sort of work you are doing.
I

• f it's RF then bandwidth and sample rates are king.
  If it's anything with fast micro controllers, then mixed signal and deep capture buffers are getting cheaper by the day.
  For motor control then you want 4 channels.
  If you are working on industrial equipment then a CatIII isolated handheld is a very handy thing.

etc.
As a hobbyist, price is always a constraint.

We are going through this process now at work and have decided that our principle consideration is faith.
What we care most about is that, when we put a probe on a signal, that what we see is actually what is there. We need that confidence above all else. (then we need Mixed Signal with protocol decodes, a big screen and deep buffer).

This is where the kiethley's and tektronix's of the world come into their own.
OK, so tek scope might be, say, 25% better than the equivalent salig, or Rigol and cost 400% more.... but it's 25% better.....
I've seen some great measurements taken with cheaper scopes and there is no doubt they are excellent value for money. But my 100MHz tek 2014 samples at 2Gs/s and has been rock solid for a decade.

I guess it's the same as "Chinese import vs old iron" in lathes....

Anyhow. Just my 2c worth.

[PekkaNF]

Thank you

Very informational answers.

And I see that even though my OP was way too long....it was far from complete.

I really need two scopes: planning to buy good, used analog scope for the reasons you both gave (and nostagia - nothing beats good dials and logical lay out that feels familiar). But the right, used (TEK) is going to take some time to find.

Therefore I'm looking a new scope and that has to be digital. I don't feel that I have need for metrosexual scopes (I believe those are called mixed signal scopes, but can't be sure, they do look scopes).

PK, you are right on all those points....

Mains isolation / CATIII that is more of an exception that rule for my current needs. I actually managed to limp along one case by using active current probe (isolated) and I think that HV differentila probe might go long way cost efective. Might be bit marginal for most of the SMPSU's but I don't work with them, more often 50-400Hz mains.

Closest to my motor controls needs are feedback sensors and such....some cases three channels would be nice.

So, I want to buy half decent general use entry level digial scope (new) that has aceptable basic functionality.

I'm trying to get my head around this question:
A) 4 CH, but less BW
B) 2 CH and 50 ohm input, but 2x BW (+300€)

Normally I would go for bigger BW, but sampling rate looks the same on 300 - 1000€ price range, real difference being amount of channels, screen size and bundled serial decoders.



Esko, does you TEK has then TIA input?
https://www.tek.com/sites/default/files/2018-03/FAQ_Passive-probe_Image4.jpg


Some stuff I don't understand well:
https://de.tek.com/support/faqs/why-isnt-tpp1000-%28tektronix-passive-probe-1ghz%29-compatible-my-scope

[eskoilola]

Esko, does you TEK has then TIA input?

To be honest, I am not sure. My previous scope had nuvistrons and this is the next generation right after that period. As I said, a dino ...
My assumption is that there are j-fets buffering the input and thus the static resistance is really big.

And please, do not ask the type, cannot remember and cannot simply walk to my shop since it is over 1000km away "am Momentan".

I know for sure that the inputs can be put into 300V at the most sensitive setting without any damage. I have accidentally measured the anode voltage of some old tube radios with it. It is so easy to forget that the IF coils are directly connected to the anode circuit ...

[eskoilola]

I know this will not help You in Your selection.
There has been memory oscilloscopes before the ADC+Memory era. I have seen at least two different approaches and even owned one.
The one I owned was a german Blauschreiber BLS-218. This has some sort of metallic powder that attaches on places where ray has passed. I don't know how that exactly worked but it was a funny device with autorange and 1 MHz bandwidth. 100% vacuum tubes naturally.
Other type has the CRT image stay glowing green until erased with a suitable antipulse. I think Tektronix has made these.

The Blauschreiber is nowdays a real rarity - there are only two samples in existence that the german museum of information is aware of. Mine would have made the third but I actually scrapped it. I am not that nostalgic - it had a great mains transformer for a 500W linear amplifier and a lot of knobs and switches not to talk about the mercuri wetted relays...

Edit: I found a website where this scope is presented here.

In case You german is not treated with rustoleum (mine is so it is not rusty) the page states about the screen that there is a potassium chloride layer on top of a mica plate. When touched by the ray it will turn dark. Erasure is done by heating. I really liked the paper like appearence on that scope.

[PekkaNF]

Jesh, those are nice relicts, but not rally what I am looking for.

I got some time ago an flyer into my email about keysight economy scopes...I was excited first, but remember seeing economy TEK or R&S scope disassembled next Rigol, showing identical innards. I'm not big fan of Badge engineering.

Keysight boasts big time:
http://www.farnell.com/datasheets/2189548.pdf

How much of that can be trusted on these "cheaper" ones:
http://uk.farnell.com/keysight-technologies/dsox1102a-100mhz-upgrade/digital-storage-osc-100mhz-2-ch/dp/2690194

I never buy options separately. I either get options for free (Rigol has offer now) or pay token fee while ordering, but I really don't like trinket trading. Therefore I'm comparing base-price models.

Like that works out much more expensive and whole lot more limited than equvalent Rigol. How much more I get something tanglible and not just badge?

About same price range TEK spesification is identical to RIGOL:
http://www.farnell.com/datasheets/2239345.pdf

Am I missing something? Do I just upgrade a little with cheapest Rigol that will do now and put balance to "used TEK account when I see one"

Pekka

[eskoilola]

Some things that caught my eye on this Keysight thing:

Operating temperature 0 - 50 degrees celcius
This means that some if not all of the components are of consumer grade. This also means that there are some components (probably the display) which will have a short life-span as it is operating at a relatively high temperature already at 21 degrees celcius.

The document does not contain word protection
Building a working protection into a measuring device is not cheap. This probably has one but I would never connect that into anything above 100 volts. Actually I could find out that the maximum input voltage is given at 200V peak-to-peak. Certainlyt not a hobbyist scope - I would turn this into a boat anchor the first day....

Seems like if I buy a new scope today that thing has a life expectancy about 5 years. I would buy a cheap chinese with just enough features and throw it away if/when it start bugging.

Edit: PDF in here.

Edit: for example a Siglent SDS1202X-E

[PekkaNF]

I was actually thinking of that SDS1202X-E Siglent, it appears to be a lot of scope for the money...unfortunately I heard (and read to find out if rumors are true) that SW is substantially more flaky that Rigol.

So I will not go below Rigol and very tempted to buy one of most popular scopes, but I'm considering spending more money for a brand name scope it performs better.

I tried to google if the Rigol DS2102E 50 ohm input is proper analog circuit and not just switched attenuator and could not find definite answer. After all: I was willing to sacrifice 2 extra channels for 50 ohm input, bit more BW and pay some more.

I tried to check Keysight DSOX1102A + 100MHZ UPGRADE. It's even more money and missing the 50 ohm input. Ends up being very close to 1000€ with taxes and therefore it's pretty much out of the "race".

Pekka

[Bluechip]

Pekka

Possibly is true, happened to me. D
Don't know whether the OS went south or the h/ware did but my Siglent SDS1102CML packed up on me after 8 months. Ch1 steadfastly refused to trigger but Ch2 was OK.
Refunded by Amazon without argument 

As Rigol UK were having an offer on ( all the add ons free and a discount  thrown in as well  )  just before last Xmas so I dived in.

Now have a DS2072A which is a lot better ...  so far ...

Dave

[PekkaNF]

Thank you Dave,

Looks like Rigol has now everywhere same price and same offer for all SW extras for free. Very good thing.

I am very tempted to go for Rigol DS2102E 100MHz 2CH
https://www.batronix.com/shop/oscilloscopes/Rigol-DS2102E.html

Based on all the information I have it offers clear improvement on my current scope.

Can you measure your scope input noise? I'm interested noise figure un terminated and terminated with blank cap or 50 Ω terminator. I'm particularry interested about 50 Ω input noise.

I checked my scope (DS1052E) one input at the time input BNC open and then blanked with 50 ohm terminator. Noise figure was pretty good, constant and low. My scope does not go down from 2 mv/div and there noise looks pretty good.

Pekka

[Bluechip]

Hi Pekka

I'll have a go at it later on for you.

Not sure what you think the S/W options are included. Click the 'Accessories' tab, you will see the bundle I got chucked in for free on  mine at the top.

Serial decode, 56Mpts etc. etc.

You need to check 

Mine:  Click accessories tab 

 www.batronix.com/shop/oscilloscopes/Rigol-DS2072A.html

Dave

[PekkaNF]

Biskit....

Couple times of the year Rigol offers Option Bundle for free. Now I don't see on this model on this shop. Pretty sure it is on sale somewhere.

Did some more Spesification and Review trawling and looks like entry scope market is such, that Keithley/Tektronix really don't want to sell for people that buy with their own money and pay real price. Pretty sure they are competive for institutions and big companies...Just checked Tektronix TBS1000B Series, 2 Channel, 100 MHz, 2 GSPS
http://fi.farnell.com/tektronix/tbs1102b/oscilloscope-2ch-100mhz-2gsps/dp/2383218

Display Memory Depth:    2.5 kpts - you have to be kidding!

In principle I like simple no-nonsense scope that does basic thing well and does only that, but honestly: it should have least semidecent analog front end, least 50 ohm option and 3 Ch (usefull at encoder stuff and serial signals) or 2+1 Ch configuration with advanced triggering to convince me to reach for wallet. But I understand really big corporatios have to slap on those products 50% overhead and therefore very little in the budget is allocated on basic engineering of basic units.

I understand that for students to many options might be intimidating, but "home/basic" button would do that. I liked single button "store" function to pen drive, but then I read that it is not as straightforwars as seen on TV.

Pekka

[eskoilola]

Pekka,

Those prices are horrific.

Like someone - probably mr. Gotteswinter - said, the chinese Lathes should be considered as building kits of lathes. To achieve durability, stability etc, one has to do some extra job.

Maybe a scope cannot be compared with this but for example if the sensitivity and noise levels are not adequate, then just build a Textronix grade preamplifier with all possible terminations and there You go.

For me the Siglent SDS1202X-E would be quite tempting as it has all the needed base structure and enough BW to cope with most of the carbage one can present to it.

This review is quite unpolarized but unfortunately in Deutsche Sprache. Basically he tells that he had already got one and that had some software faults, they replaced that and this one "seems to be quite OK". At leas he has a decent reference - A Rohdeschwartz scope .... Those devices used to be really reliable and did not leave much to wish for - except for lower prize. I have a basic signal generator (9kHz - 2GHz) made by this company and that device is really something. If You can find a device made by them - those are usually quite good.

[PekkaNF]

Thank you.

Went through that video twice. Second time with English automatic translation, that part of the time helped me a lot to understand what was going on (my German is rusty, studied it few years).

That video was interesting, but most of the time I had no idea what was the input signal and what response was supposed to be.

Like the 200 MHz, but not sure how does it handles the basic stuff, somehow it feels bit like a Acer of the PC:s

Bit late to get decent old stuff here. Eflop and Balmer killed the Nokia and their lab stuff has trickled out. To buy R&S stuff at list prices is not my option.

At this price range big time brand name are out of game and second choices seem to fare good enough.

Some more specification reading and you tube reviews to watch.

Pekka

*typos

[PekkaNF]

Esko,

I agree about the amplifiers, probes and such, they are really vital for measurement and least as important than as the "scope". My previous "reference" probe for 50 MHz scope is 350MHz new 1:10 probe and I compare other probes to that. That still might just do for the new scope.

Luckily I have a friend that practically lootted bunch of high quality test equipment from one lab and works in one small calibration comppany. I take bunch of my stuff with me and he goes trough them and tells mee what are absolutely awfull and which is passable to certain limint.

He found one 50 ohm terminator that had a non SMD terminating resistor inside it and it had absolutely horific frequency behavior from few MHz up. It was bought from Reichelt.
https://www.reichelt.com/de/en/Test-probes-and-BNC-adapters/BNC-50-2W/3/index.html?ACTION=3&LA=3&ARTICLE=5648&GROUPID=7230

Pekka

[PekkaNF]

Dave,

Pretty much decised to fo for Rigol DS2102E...costs the same every country and seems to have offer for free triggering option and serial encoders everywhere.

For me it's the mother of compromises, I don't feel too happy about it, but it looks like would do mst of stuff I need to do and get me started on thoset that it won't give clear cut answer. Then I take myself and my problem around 30 km south and visti my firned that has monster scopes, spectrum analyzer and some esoteric EMC measurement gear I have no idea to get me trough.

I did like some features on Keithley and some brand scopes, but all up price gets that high that I could allready buy a used professional scope.....the next stop.

I sent enquiry to one local comppany, will call them and most likely to buy the scope on Monday.

Now, I basically have only two questions on my mind.....

1: Anybody have idea on Rigol DS2000 series scope input noise levels? What I have read, they should not be that bad and input stage should be reasonably well shielded.

2: What is the real practical difference with Rigol DS2102 A and E versions? I see from the spec that A-version offers 2 GS/s to one channel (and 1GS/s per channel when both channles are used and E version offers 1GS/s to each channel.

Also A-model seems to go for higher nominal frequencies, but at additional price.

I know that I have tnedency to go trough much of the information to make a educated descission. Hope I'm not making everybody grazy. Just last week I got bitched up once being too thorough on solving one problem, but also got compliments of solving it when everybody else had given up.....I really don't understand people.

Pekka

[PekkaNF]

I asked questions from two comppanies. One answered promptly my questions and I just ordered the scope from there.

The scope is Rigol DS2102E. Rigol has now deal for free SW options, and I felt that it probably will come handly some time.

Pekka

[PekkaNF]

Got it yesterday. powered it up and tried to find my way around it. Feels familiar right away. I like that it has separate controls for both channels. "Auto" funktion is a little different.

Screen is really significanlty bigger and more clear. Unfortunately they have used up the bigger resolution and text is not bigger, maybe it's bit more clear. hope there is an option for slightly bigger text. Hate to make mistake with a speck of dust and decimal indicator.

Boot takes longer, but then scope is pretty responsive. Most functions are fast.

Most SW has a "Trial" status, but I got woucher with the scope. Have to see how to upgrade serial decode etc. it all should be included.

Haven't really tested it, but it seems reasonably good.

[PekkaNF]

Just upgraded succesfully freebie licences.

Licence key is printed "Software licence certificate" pretty much followed the YouTube video, and now all options are with "official version - never expires" status

That video is really good, then instructions on manual and specially on the licence paper feel really iffy.

This site generated the licence file:
http://licenseen.rigol.com/CustomerService/ProductRight_EN

I downloaded the .lic-file onto root of old USB-memory stick root, ejected it from the laptop and put it into scope front connector. Pop-up screen came up right away and soft button press was all that was needed to change all utility statusses from "trial" to "official".

Great.

Pekka