Want to start playing with PicoScope

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fixingstill
Newbie
Posts: 2
Joined: Wed Feb 05, 2020 5:28 pm

Want to start playing with PicoScope

Post by fixingstill »

Want to start playing with PicoScope
Let say I want to do a relative compression test and inductive pickup of the ignition coil. Something like this:
https://www.youtube.com/watch?v=6H_lEGUcUFY

And I see the 2204A are available on ebay for $120 ish.
Any affordable current probe and inductive pickup for the coil?
Does 2204A support current software?
Or better to buy a current kit/product?
Again, I am new here and just trying to learn and spend minimum $ to start.

josegumby
OneWave
OneWave
Posts: 31
Joined: Sun Aug 27, 2017 3:46 am

Re: Want to start playing with PicoScope

Post by josegumby »

Hi,

The 2200 series scopes are NOT automotive scopes, and therefore will not work with the automotive software.

I originally purchased a 2405A a few years ago, not realizing this, and found out the hard way that it wasn't suitable for automotive. I eventually purchased an automotive scope, a 4425, and I am extremely happy with it.

Some key differences that make it not suitable for automotive:

1. The input voltage is very low compared to automotive, +-20V for the 2200, compared to +-200V for the (newer) automotive scopes. This is important when measuring fuel injectors, and possibly variable reluctance sensors (crank/cam shaft sensors, wheel speed sensors, etc). And also primary iginition, even with a 10:1 attenuator. You could get voltage spikes upward of 400V from primary ignition, which would be 40V with a 10:1 attenuator. Again, the 2200 is only rated for up to +-20 V.

2. The vertical resolution. The 2200 is an 8-bit scope, which translates to 256 vertical measurement levels for any chosen voltage range. The automotive scopes, on the other hand, are 12-bits, which means 4096 vertical measurement levels for any chosen voltage range. For an example, here are two fuel-pump current measurements, they are from different cars, but you can easily see the difference between the two scopes. Click on each one individually to see them full size to really see the difference. Now imagine trying to see a fuel-injector pintle-hump, or oscillations at the beginning of an ignition-coil current ramp without the automotive scope.
2400 series scope.png
4425.png

3. The 2200 and 2400 series scopes are small and have a hard outer shell. Anytime I tried to use it under the hood, it seemed no matter where I put it, it just wanted to bounce around, and try to slide off from engine vibration (I don't have a scope cart). The automotive scopes are a little bigger, heaver, and have a rubber coating all around them, which helps them stay put. They also have a fabric-loop at the back of them so that you can hang it from the end of the hood if you wanted to. If you do hang one from the top of the hood, however, if the car has hydraulic hood-lifts to keep it up, you might want to make sure the hood doesn't fall under it's own weight (and on top of your scope), but taking a cheap pair of locking needle-nose pliers, putting a couple inches of fuel-hose over each jaw, and clamping over the hydraulic lift to help that hood stay up. Experience....

4. The leads that come with the 2200 and 2400 scopes are very short. They are designed for T&M (testing and measurements) environment. The ground lead is only a couple inches from the measurement side of the lead. So finding a place for a good ground, can be challenging. Altough you can buy longer leads, the automotive leads are very well shielded to protect from all the electrical noise under the hood.

5. If I'm not mistaken, the automotive scopes have self-resetting fuses inside them, so they can take *some* "mistakes". The occasional temporary mistake of sending too much voltage into the scope. I wouldn't count on this as an excuse to avoid using common-sense though.

I'm sure there are many other advantages to an automotive scope, such as speed, built-in probes in the software, and automotive help-guides and pre-sets. I know that the automotive scope is quite a bit more expensive, but it is well worth it. It really is. If you look on ebay, you might find an older automotive scope to suit your needs. Which is going to be better than a non-automotive scope any day of the week (for your purposes). Stay away from the old parallel-port scopes. Some automotive scopes are just too old. Get a 4-channel scope if you can, if you decide you need to upgrade from a 2-channel to a 4-channel scope later, it's a tough pill to swallow. Do your research and make sure what you get is compatible with the automotive version of the Picoscope software.

Hope this helps.
Thanks,
Curt

josegumby
OneWave
OneWave
Posts: 31
Joined: Sun Aug 27, 2017 3:46 am

Re: Want to start playing with PicoScope

Post by josegumby »

Oh I almost forgot - without an automotive scope, you'd be missing out on access to the waveform database as well. :)

Here's another post with a reply from one of the Pico staff members with good information about the comparison between the automotive scope and non-automotive scopes.
https://www.picoauto.com/support/topic19501.html

fixingstill
Newbie
Posts: 2
Joined: Wed Feb 05, 2020 5:28 pm

Re: Want to start playing with PicoScope

Post by fixingstill »

Thank you very much for the info. I am onto a 4425 then.

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