Oscilloscope kits – any recommendations?

[Robert Atkinson 2Participant @robertatkinson2]

Posted by Bazyle on 10/05/2020 12:10:47:

If not leading the thread off topic too far is there a low frequency spectrum analyser? I'm thinking in terms of analysing lathe vibrations so low frequency like audio range.

The Picoscope software has an FFT function built in so they also act as spectrum analysers. Their automotive software has specialised vibration analysis and balancing functionality and they sell accerometer kits for it. https://www.picoauto.com/products/noise-vibration-and-balancing/nvh-overview
Unfortunatly it only runs on the automotive versions of their 'scope adaptors. As these have 12 bit resolution (most 'scopes are 8 bit) it works quite well. I do have one of their automotive 'scopes and accelerometers but have never need to use it for vibration. If anyone near Cambridge wants to have a play after the lockdown I'm game.

Robert G8RPI.

[BazyleParticipant @bazyle]

Some interesting responses there, thanks. It seems there is always someone on here who has some experience in just about every topic one can come up with.

[Robin GrahamParticipant @robingraham42208]

Thanks for replies – too many to respond to individually, but all appreciated and I've followed up on suggestions..

I was asking about 'kits' (in the sense of DIY soldering etc) because I thought they were the only alternatives to 'proper' bench scopes. Much as I'd like a proper scope, I can't justify the cost for what I do.

From the discussion it seems that there is a middle ground – pico etc. But for the mo it seems that the KKmoon offering that Neil recommended will do what I want for not much money.

Duncan – many thanks for your kind offer. Your old pico may well be good enough for what I need to do. I'm typing on an ancient computer with a parallel port! All my ancient computers run Linux though – maybe that would be a problem. I'll PM you.

Les – thanks for your post giving data on the various protocols used by different manufacturers – it should be made a sticky.

Robin.

[Brian OldfordParticipant @brianoldford70365]

If you're not in a rush. **LINK**

Or if you want it quicker **LINK**

[metalfettlerParticipant @metalfettler]

Posted by Andrew Johnston on 10/05/2020 12:40:27:

Posted by Bazyle on 10/05/2020 12:10:47:

If not leading the thread off topic too far is there a low frequency spectrum analyser? I'm thinking in terms of analysing lathe vibrations so low frequency like audio range.

Don't know if one is available for the amateur, but they exist for the professional. They're called signal or waveform analysers. They're part spectrum analyser, part oscilloscope and part network analyser. Generally they will perform Fourier transforms, measure the response of a filter or amplifier and allow waveforms to be shown over time. The latter is often called a waterfall display. Successive scans in time are displayed offset in two dimensions so you get a 'waterfall' showing how the signal changes over time.

In the past I've used them for measuring filters with arbitrary pole/zero locations, for assessing the performance of active noise systems (*) and the performance of a 30Hz radio.

Andrew

(*) Being stuck 150ft up on an electro-precipitation stack at a cement works, at midnight, trying to work out why an active noise controller isn't working doesn't rate highly in my list of fun things to do.

[Clive FosterParticipant @clivefoster55965]

For pulse timing applications the more channels the better, within reason.

Chasing timing errors down with a two channel scope can be a miserable experience because you pretty much have to devote one channel to a reference so with several potential pulse string to pulse string error possibilities you are forever swopping around. Not ideal for the inexperienced.

8 channels are much nicer in my experience but then connections can be difficult. Once all hooked up youhave a clear view tho'. I often found 16 too many.

Bigger screen helps.

Ideal for pulse timing and similar would be a very limited box able to display pulse trains linked to a tablet for the display and control. At modern electronics prices a one job tool is viable. Needs to be buy, not build, with robust software and a manual.

Clive

[metalfettlerParticipant @metalfettler]

Dave, (SOD)

I have an Instrustar IS205A usb, datalogger and spectrum analyser which does a fair job on frequency analysis but no way can I get a printout. Current cost is about £65 from China via ebay.

Also have a Hantek 6022BE similar usb scope but not sure it does FFT; cost around £40. Best to search both on ebay for full specs.

Sorry I didn't get back to you on PM re. vibration lathe analysis but I just bought a Raspberry PI and I think I have fried my brain. What the learning curve is I daren't guess. Over the years I opted away from an electronics career to be a noise and vibration consultant – my workshop is testament to the deep allure of swarf and oil.

Basically for a manual lathe f(0) is mandrel rpm dictated by balance quality riding on background slush (noise) generated by lubicant swirl and sundry resonances plus motor speed and electrical noise. All other frequency peaks relate to gear meshes and bearing noise don't forget beat frequencies including relative speeds and rolling element speeds. Hewlett Packard used to do a handy booklet on this.

Hope this helps, Les

[SillyOldDufferModerator @sillyoldduffer]

Thanks Les, very interesting! I didn't know it was possible to buy a logic analyser for that kind of money. I'm going to order one!

I sympathise with your RaspberryPi shock – that little card has 50 years of software complexity in it! Hours of 'fun' ahead!

Your last paragraph opened up some interesting ideas as soon as I followed the clue. For example, motor vibration caused by 'soft foot' , which is when the motor doesn't sit evenly on it's mounting. Detected by putting a DTI on the motor and slackening eacjh bolt in turn; if the DTI registers more than 1 thou of movement the foot should be shimmed. I'd never have thought of that!

Cheers,

Dave

[Anonymous]

Posted by Clive Foster on 01/06/2020 18:29:30:

Ideal for pulse timing and similar would be a very limited box able to display pulse trains linked to a tablet for the display and control.

They're available and called logic analysers They concentrate on displaying time relationships between channels and are less concerned with voltage levels. They usually display a channel as 0 and 1 based on the levels of a selected logic family. Relatively cheap ones are available, although I can't remember the details. On the other hand fancy ones (32 channels and upwards with bandwidths into the GHz) can approach £100k. The better ones can morph a number of channels into one line with a binary or hex equivalent of the channels. When looking at address and data buses that's often more useful than displaying individual lines.

Andrew

[fastdaveParticipant @fastdave]

Go with the moderator mate, save yourself money and KMoon is incredibly clever – I have used several of their innovative devices – I have Hameg scope and all sorts of radio analysis equipment, but Kmoon takes value for money – I got one of these little scopes – way acurate enough by it's very nature, and a little signal generator (same people) – totally impressed – scope even comes with a probe!

Dave, Fife.

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