Help Choosing an Oscilloscope

[Autotecheng]

Hi,

I am trying to find a good entry-level oscilloscope to use with automotive applications. I was wondering if the Pico 2205 would be adequate for me.

specs:

http://www.picotech.com/picoscope2200-specifications.html

I want to scope transducers for shaft speeds and pressure changes, like camshaft position sensors, crankshaft, input / output transmission shaft and wheel speed and pressure like manifold vacuum or exhaust backpressure, and also DC motor amperage using low amp inductive probe. Maybe ignition secondary voltage using inductive pickup in the future.

I'd like to see things like inductive kick and coil "ringing" And check slower things like throttle position sensors.

In the future I might want a scope with four or more channels.

I would just appreciate any advice on whether the 2205 would be capable/incapable of sampling the aforementioned. I know their kits come with higher level scopes.

It will take me about four months to save the money for it.

Thanks for your help,
-Andrew

P.S.

For reference about the frequency and type of signals I am interested in please see

http://www.picoauto.com/waveforms/

 

[VEBill]

Many of those parameters (especially the pressures) would be measured with a gauge or a meter (on the appropriate sensor). Others (e.g. throttle position) can be read from the OBD-II port.

Plenty of cheap scopes on the market if you really need one.

 

[Skogsgurra]

PICO seems to have invaded the automotive market. Not so sure why - it is not very practical to use two items to get the result of one, like a dedicated scope.

And, if you really want an USB scope, there are lots of other USB scopes at a much better prices.

The Rigol scope is quite good. I have one and must say it is extremely good value for money.

Metrix/Chauvin-Arnoux also have a small LCD scope with very long battery life. Can't beat Rigol on the dollar side, though.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[danw2]

I, too, vote for the Rigol DS1102. It goes for about $400 USD.
Great scope for the money. Several very well done tutorials on YouTube (1052 is the same box, just less bandwidth).

 

[Autotecheng]

The rigol scope you linked to looks fantastic. I have to look into it more.

>Many of those parameters (especially the pressures) would be measured with a gauge or a meter (on >the appropriate sensor). Others (e.g. throttle position) can be read from the OBD-II port.

Yes there are many different gauges we can use, but gauges are limited in terms of their response time, their precision, and their ability to show how a state fluctuates over time, and they are not capable of creating permanent records either.

A regular fuel pressure test gauge for example can tell you the fuel pressure, and if you use one with a flow meter you can measure flow as well. And if you can cycle the fuel injectors one by one you can measure the pressure that each one drops, but-

If you were measuring the pressure of the fuel rail in real time with a transducer you would be able to see if the fuel delivery was balanced or not without regard to any mechanical or electrical problem. That's an interesting capability.

If you compare scantools, then there are some that have an injector balance test which works in relatively the same manner, but one problem with scan tools is compatibility. It is exceedingly difficult to be compatible with every PCM/ECM, and because auto manufacturers want to keep work in house they have anticompetitive motivation to make it more difficult to interface with. I work at a dealership and our tech support people have been troubleshooting our scanners for several weeks because the latest model vehicles are not compatible with anything other than the most up to date scanners and they are having technical problems updating.

That's the OEM! Good luck trying to diagnose one of our vehicles through the DLC with an aftermarket tool.

The other reason that I am interested in the use of oscilloscopes is that an engine control module or powertrain control module can only provide me interpreted information. If signals are faulty and cause misinterpretation then the scan tool cannot help me.

The most egregious example of this that I have yet seen was an ABS fault that was misdiagnosed repeatedly. The HCM was replaced something like THREE times before someone was able to correctly diagnose the problem (and they used a scope to do it). The problem was a wheel bearing with an integrated tone ring and speed sensor. Non-serviceable, inseparable and not inspectable. Wear particles from the bearing had damaged the tone ring and the speed sensor was producing a faulty signal that lead to intermittent problems with the ABS.

I think the old saying for software is "garbage in, gargbage out", so in some cases I might want to look at the input with a scope.

I am not saying that the traditional tools and resources have lost their place, but I would definitely say oscilloscopes can provide a valuable exclusive diagnostic service.

One other reason I would like to use one is for use in training students in the electronic instrumentation of engine/powertrain systems. Scopes are able to provide good visualizations of what is happening in real time.

Thank you all for you advice, I will look at the rigol scope more closely.
-Andrew

 

[catserveng]

In the heavy duty truck market I started using a scope pretty much right after we started selling electronic engines, as you pointed out lots of things the diagnostics don't tell you, especially sensor issues that are the result of bad connections, noise or power supply issues. I set our lead techs in our truck shop up with Fluke 98 Automotive scopemeters and also had the PV350 pressure modules and a thermocouple to millivolt covertor so they could feed in a temperature or pressure signal in one channel and compare to the on engine sensor signal.

The scope was especially helpful in finding odd problems with speed timing sensors, and later communincations problems. We found the more the tech got around it, the more uses he found for it and it really helped in troubleshooting difficult recurring problems.

The 98 scopemeter was a tough beast, took a ton of abuse, like falling off truck tires, getting dropped, etc. We found it easy for the techs to get started with. It seemd pricey at the time but survived in the environment and performed as expected.

My son is working on the heavy equipment side of the business, and now moving into a more diagnostic role, I just put together a kit for him using a Fluke 98 off ebay, a Fluke PV350 pressure module, and a Fluke 80 TK thermocouple module. So far it is meeting his needs and he is finding more uses for it regularly.

I know Fluke has had some issues with newer scopemeters lately, but the 98 always served me well, I also regularly use a 123 scopemeter for a lot of industrial engine applications. Maybe more money than you want to spend, but in the shop environment might be worth it.

Mike L.

 

[xj25]

We have a pico 3200 scope.

It works well, it is light, you can port it without problem and the software is quite complet including spectrum analyzer soft with a lot of options and operations, etc. (with the normal BW limitations of the scope)
You can define custom probe transformations to use special defined probes.
Export to JPG, excel table, text etc.
Delay triggers, single shot, AUTO.
Save on trigger.
Can do realtime postfiltering to remove unwanted noise or artifacts.
"Persistent" signal mode for checking phase delays etc.

As a thumb rule choose as a minumun BW x5 the maximun frequency that you need to capture (better x10).

Sole caution. Buy fixed probes x10 to avoid damaging the inputs. With a x1 probe you can easily have problems if uses voltages >30V (I did and know have only x10 or more probes).

Regards

 

[drhoo]

I have used a picoscope 4224 and liked it fairly well. It is great for capturing long records and exporting the data to analyze.
The gui would crash occasionally, mostly i think when the usb cable was moved while it was acquiring.

Also currently using a Rigol DS1052E and like it a lot. It works well and seems rugged enough.
For $335 on the Rigol website it cannot be beat.