Automotive oscilloscope recommendations?

[JOEPRO]

I repair my own cars and currently have Canbus issues on a w220 Mercedes.

I have always meant to get an oscilloscope for being able to "view" the readings and ideally to generate feedback.

Budget of around £100 say or more depending on functions etc.

I see the likes of this on ebay which does look veey good for the price and has an inbuilt battery:

Pardon our interruption...

 

[Nomad]

Bookmarked as it's something I've been considering for a long time, will watch and see what is suggested

A thought, last time I looked there were plenty of cheap options that would connect to a laptop or USB - maybe an easy way to get the chart onto a much better display than a cheapo handheld screen

 

[JOEPRO]

I guess for can bus testing I really need a 2 channel one. This one comes up with 4.9 out of 5 star reviews and includes signal generation function



This video is succinct and shows its functions including when in 2 channel mode - looks good to me

 

[Ubique]

Picoscope 2000 series, more than capable of scoping all variants of CAN & LIN, will also decode to some extent.

https://www.picotech.com/oscilloscope/2000/picoscope-2000-overview.

That Chinesium is probably OK for an indication, I'd trust a car salesman over it for a measurement though.

 

[JOEPRO]

A thought, last time I looked there were plenty of cheap options that would connect to a laptop or USB - maybe an easy way to get the chart onto a much better display than a cheapo handheld screen

for automotive use I would rather have an all in one device with its own battery and screen. No need to have another laptop and charger etc going to use it.

 

[voipio]

The 200kHz bandwidth of the scope in the first posting is too low to be able to see some of the events relevant to CANBUS.

 

[JOEPRO]

Picoscope 2000 series, more than capable of scoping all variants of CAN & LIN, will also decode to some extent.

https://www.picotech.com/oscilloscope/2000/picoscope-2000-overview.

That Chinesium is probably OK for an indication, I'd trust a car salesman over it for a measurement though.

Your linky is not working for me. Says outdated link

I presume you mean this type of thing yeah?

Pardon our interruption...

Would require a laptop but I could live with that for a good reliable device which that looks like to be fair.

 

[Ubique]

Odd, I've just copied & pasted it... but yep, 2204A is the one I've been using for the last six years - don't bother getting the probes, you won't use them. all you need is a BNC to 4mm adapter lead (or two) and remember that the ground is tied between the two inputs, CAN high is above 0V, CAN low is below 0V - they must mirror each other. MS-CAN will operate with one leg down, HS-CAN needs both legs operating to work at all.
Carefully check the 'knee' of the waveform, any rounding indicates corrosion in the wiring - in the case of Mercs. check the CAN concentrator blocks for corrosion and a decent ground connection on slot 1

 

[Ubique]

Forgot to mention, the software is 'free' and updated regularly, mine runs happily on an old Panasonic CF-52, it's worth downloading the software first and running in 'demo' mode to see if you get on with it before splashing cash on the hardware. It works great for me and I can't see the need for the 'automotive' version - as long as you know what signals to expect, if you need some hand-holding, then the automotive version makes sense, but at a cost.

 

[Keithmac]

I bought a Snapon Verus Pro D10 for its 4 channel Scope.

Great bit of kit.

 

[sako243]

@JOEPRO Do you want a sillyscope or actually do you want a CANBUS diagnostics tool? The silly scope unless it's got some nifty features and triggering will make actually reading canbus measurements difficult at best. It's useful to diagnose signal quality etc., but if what you're interested in is reading messages you might be better off with a CANBUS transceiver. Microchip do a USB based one for example which has a piece of software to display all messages etc.

 

[premmington]

I use/own a couple of Picoscopes - I have never in all this time ever needed more than two channels for anything.

 

[Turbo]

Don't know anything about scopes but I would really recommend getting a laptop for workshop use. I have one with diagbox psa diagnostic software on it, will be loading the workshop manual for my van on it and will likely be installing the vag diagnostic software on it for our VW Golf.

An old tough book is ideal but it needs to still have a good battery. A 14" screen is a good size, not too big.

I would imagine that you have a lot of merc manuals to install, very handy having them all in one place ready to use.

 

[Ubique]

@JOEPRO Do you want a sillyscope or actually do you want a CANBUS diagnostics tool? The silly scope unless it's got some nifty features and triggering will make actually reading canbus measurements difficult at best. It's useful to diagnose signal quality etc., but if what you're interested in is reading messages you might be better off with a CANBUS transceiver. Microchip do a USB based one for example which has a piece of software to display all messages etc.

Analysing the data stream is really only useful if a module isn't transmitting, and even then, there's other signs without a dedicated bit of kit - such as no response from diagnostics. In the case of malformed frames on CAN, a data analyser won't be any help as they're simply discarded by any node receiving them, so won't show as a datastream. Most CAN issues are wiring / termination related and a 'scope is the best way of finding the area of defect as they are data-agnostic. The only other (rare) reason for a CAN to be brought to it's knees is a module going postal and flooding the CAN with malformed or genuine packets, a data analyser could be useful, but wouldn't tell the whole story like a 'scope would.
I do have a cheap analyser, rarely use it though - it's a WOYO PL007 (Chinesium, obviously....)

 

[JOEPRO]

Don't know anything about scopes but I would really recommend getting a laptop for workshop use. I have one with diagbox psa diagnostic software on it, will be loading the workshop manual for my van on it and will likely be installing the vag diagnostic software on it for our VW Golf.

An old tough book is ideal but it needs to still have a good battery. A 14" screen is a good size, not too big.

I would imagine that you have a lot of merc manuals to install, very handy having them all in one place ready to use.

Thanks and yes I have several laptops for the garage including a tough book with full Mercedes star on it. So I could use any of those with a scope.

 

[Ubique]

I'd also recommend getting the Pico backprobe pins - they're the best ones I've found. Confusingly only on the Pico Automotive site https://www.picoauto.com/products/accessories-clips-and-adaptors/red-flexible-back-pinning-probe

 

[sako243]

Analysing the data stream is really only useful if a module isn't transmitting, and even then, there's other signs without a dedicated bit of kit - such as no response from diagnostics. In the case of malformed frames on CAN, a data analyser won't be any help as they're simply discarded by any node receiving them, so won't show as a datastream. Most CAN issues are wiring / termination related and a 'scope is the best way of finding the area of defect as they are data-agnostic. The only other (rare) reason for a CAN to be brought to it's knees is a module going postal and flooding the CAN with malformed or genuine packets, a data analyser could be useful, but wouldn't tell the whole story like a 'scope would.
I do have a cheap analyser, rarely use it though - it's a WOYO PL007 (Chinesium, obviously....)

That is fair enough, I was just trying to clarify what @JOEPRO was wanting to do. Most of the stuff I've done with automotive can has been more on the reverse-engineering / integration side so an analyser has been far more useful. I have a 4 analogue-channel 100MHz bandwidth scope with 16 additional digital channels for day to day stuff which is used for what you describe. Out of budget (by an order of magnitude at least) though.

 

[Red'n'Black]

That is fair enough, I was just trying to clarify what @JOEPRO was wanting to do. Most of the stuff I've done with automotive can has been more on the reverse-engineering / integration side so an analyser has been far more useful. I have a 4 analogue-channel 100MHz bandwidth scope with 16 additional digital channels for day to day stuff which is used for what you describe. Out of budget (by an order of magnitude at least) though.

The other thing to bear in mind with the higher-end scopes - Tek, Keysight etc - is that the decoding and analysing features are a $$$$ software upgrade, one for each protocol CAN, USB, Ethernet etc. The makers are relying on the fact that at this price point, it's usually somebody else's money.

The cheaper ones, Rigol and I think Pico, often throw this stuff in for free.

 

[JOEPRO]

Yes I suppose in terms of my Mercedes and having the Star software means a scope is not strictly necessary.

I have had can fault finding success in the past by finding the connector strips (normally several of them in different locations) and unplug one by one and see what changes.

If modules which were offline then come back online search for that it was you unplugged. Then repeat test and bingo. That is what is bringing the can bus down so hone in one that item.

With Star or other diagnostic tools if the can bus is down then it won't tell you much as it cannot then communicate with one or more networks in the car.

So I may just stay with this approach.

My thoughts on a scope were wider than this too and perhaps I should have clarified that.

So for example, if a wheel speed sensor is throwing codes you could test it with a scope to see is it generating a signal. And further, compare that signal to another wheel. Then check the readings for decay or other faults at the ECU end of the cables. Or generate a signal and send it up the line and watch the ECU live data if it picks it up and then you know its the speed sensor at fault.

I have a redneck solution to this at present. Which is a spare known working S class hub with sensor that I use to manually "inject" signal and watch the live data. A scope would be a better way but then I may not have the time to fully explore it and get used to it like the likes of Eric O can!

 

[My Old Landy]

I have a Picoscope 3404D which I just dragged out to see if it still works.
It does then I looked up the current price, over £900!!!
I suspect there are cheaper variants