The PicoScope 2204A is a really cheap oscilloscope, but can it be used for automotive applications in place of the more expensive PicoScope 4425?
PicoScopes for automotive use are in general really expensive. When we talk about PicoScope Automotive, a price comes in our minds around three to four figures with a dollar sign in front - $$$$. In this article, we are going to look at one of the cheapest oscilloscopes that PicoScope make and ask, how suitable is it for automotive use?
The PicoScope Automotive oscilloscope is an impressive bit of kit. You get the nice box with all the different accessories inside, there are four channels, amp clamps and all the probes to go with it. The PicoScope Automotive software has some nice little features there to help you with automotive specific issues; like being able to access reference waveforms and custom probes ready set up plus the Automotive Diagnostic software. Those who are looking to buy the PicoScope Automotive kit will know that it can go well into the thousands of dollars, and that is not affordable for all. However, PicoScope do have a range of entry-level scope and they are very affordable; the 2000 series. At the bottom of this range is the PicoScope 2204A. You can get this scope plus some automotive grade probes for under $200. There are a few versions of it, but will it be enough to perform routine automotive diagnostic tests?
The PicoScope 2204A is a 2 channel 10MHz oscilloscope. There is also an Arbitrary Waveform Genertor (AWG) output which can generate a variety of customized signals; not available on the PicoScope Automotive scope!
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Open up the box of the PicoScope 2204A and inside you get:
What you want to do is get yourself some of the Hantek Automotive probes and they are really quite cheap. You can fit your back probes and alligator clips on them quite easily. You can also piggyback them onto each other. If you are using two probes and you want to take one reference point as earth, you can just connect them together.
Head over to picotech.com and install the PicoScope 6 software. Connect the oscilloscope up and the drivers are automatically installed, and you are ready to go. Once connected, the first thing to do with the oscilloscope is to check the battery voltage. You should get a flat line at 12 volts if everything is working ok.
We performed a number of typical tests on a 2012 BMW 320d. We tested a digital airmass meter, a fuel pressure sensor in a ‘draw’ mode and ulitmately, CAN Bus! We used the Hantek HT30A Automotive leads with a 4mm/banana Back Probe and Alligator Clip.
Starting with an air mass meter reading, we are looking for a frequency modulated signal. Be incredibly careful when using these types of back probes. Don't push the probe too far in or it will damage the connector. When you look at the air mass frequency modulated signal in Auto mode, it flickers between 5 and 10 volts.
Manually select a 5 volt scale to make sure you get a constant pattern on the screen and set the trigger already set, you see the little yellow dot in the middle. It's really quite stable and looks exactly the same as what you see on the Pico Automotive scope.
Now we take a measurement of the high-pressure fuel sensor on the fuel rail and this measurement is going to be much slower than the air mass meter.
We will change the time setting to 2s/div to take a measurement over a period of seconds whilst we rev up the engine and watch the signal change. Again it's really the same as what you would see on the PicoScope Automotive set up.
Now we test the CAN Bus network signal. We take a reading of the powertrain CAN from the engine control module. Now setup channel A and channel B; you can use channel A for CAN Low and channel B for CAN High. Get the ground connectors piggybacked onto each other to share a ground.
Turn on channel B to get the two patterns displayed. In Auto mode it flickers ‘over range’ a bit, so you can put the voltage up a to 10 volts to stop that from happening. Reduce the time scale so that you get a better picture of what you should be seeing for a CAN signal, 50us/div is good. We can also set the trigger to the start of the message which is slightly higher than the rest of the signal. Here you can see the data package that was captured.
We can use the amplitude cursors to measure the voltage; all you have to do is drag the blue box down for channel A and drag the red box down for channel B and you get a little measurement box open up in the center of the screen at the top. This shows the voltage at the given points on the waveform.
You can do the same for the time cursors from the sides of the screen. The little white boxes start off in the bottom left-hand corner, and when they are slid across the screen, the time measurement is also displayed in the box. Pull another ruler across to measure the difference.
The PicoScope 2204A is a great tool for the money and will help you diagnose most issues. It would be good to have 4 channels to give more flexibility. The 2204A will also struggle to capture large amounts of data that can be zoomed in to after; but for measuring real time signals, it’s perfect! The scope is also compatible with the same accessories available on the Automotive kit:
Come and check out the channel to see the PicoScope 2204A in action where I use it to diagnose multiple issues!