Pico Scope Review
Picoscope Software Installation in Virtualbox on Mac Os X
Since I don’t have a plain PC available I needed virtualization software to run PicoScope on my Mac.
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Although native Mac OS X software is preferred, it’s not currently available.
A Linux version is available although it is not fully supported by picotech. We hope to see a Mac version soon.
It is currently only available in virtual machines, such as Parallels Desktop, Oracles VirtualBox or VMware Fusion.
For this test Oracles VirtualBox was used.
I decided to download the latest version of picoscope instead of the CD and install it on my Windows 7 virtual machine.
PicoScope started properly, but it couldn’t locate the connected device at first.
Further investigations of the windows device manager showed that the driver was installed, but it could not be started.
VirtualBox standard USB ports only support USB 1.1. It is possible to enable 2.0, but this can only be done after installing an extension pack.
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See https://forums.virtualbox.org/viewtopic.php?f=24&t=36752 for more information.
PicoScope works perfectly after these modifications, as you can see in the photo below.
Injector Voltage And Amperage:
Injector voltage and amperage is a common measurement performed with a scope. On a port fuel injection vehicle, the technician can monitor the amperage and actually see the pintle “bump” in the waveform as amperage builds. Amperage ramp and amount will indicate excessive resistance and short circuits. The tech will monitor the voltage and can inspect the pintle closely by watching the “bump”, which is the spike in voltage.
That’s all true with port injection, but these images show a gasoline direction injection (GDI) injector. The patterns are different, because GDI injectors are initially charged with a higher voltage (60+ volts), then held open with a PWM 12 volts. The pattern looks quite a bit different from a port fuel injection injector. The tech can still monitor for proper amperage and adequate voltage. All scopes were able to handle injector voltage and amperage. The Pico 4425 (figure 3) and the Autel (figure 4) can handle the voltage without any scope modifications and did an excellent job. Pico 2204a and Hantek have relatively small input voltage capacities (figure 5 and 6). These scopes are limited to 20-volt max input, so the injector voltage would possibly fry the scopes if precautions weren’t taken. The probes of the Pico 2204a or Hantek test leads come with a 10-x setting. Using this 10x setting will reduce the voltage going to the scope by 10 times, so the 60-70 volts will get knocked down to 6-7 volts, which makes the scope safe to use with the higher voltage injectors.
Conclusion: The Pico 4425 and Autel make it easy to check injector voltage and amperage without requiring any special precautions when using the scope. The Pico 2204a and Hantek require the use of the 10x setting on the probe or the use of an attenuator to reduce the voltage to the scope since they have low input voltage capacity.
Both Primary and Secondary Ignition:
Those of you that are old, like me, will likely have experience with ignition scopes. They were the monsters that lived along the wall in a shop. The digital storage oscilloscope came on the market as computers and hardware became more advanced in the 1990’s. Now that digital storage oscilloscopes have become more common, technicians still use them to measure ignition primary and secondaries while diagnosing cars. My test car had coils with transistors in them. They had power inputs, ground and signal circuits. A 5-volt square wave is all that’s needed to tell the coil what to do and when. The only measurement I was able to make on this vehicle were coil amperage, secondary voltage.
The Autel kit come with a secondary ignition clip that is placed on the spark plug wire and the Autel and Pico have a custom probe already installed in their software. Pico 2204a does not have this probe, however you can download Pico Automotive scope software to “export” the automotive probes from Pico Auto. The probes will then be “imported” into Pico 6. Although the Hantek can’t set custom probes for you, it is possible to see the pattern and do manual conversions if necessary.
Conclusion: The Pico 4425 (figure 7) and the Autel (figure 8) worked great at checking secondary voltage and primary current. The probes were custom made and required very little configuration. Pico 2204a figure 9 requires the probe to be imported. However, it will work fine as long as you set your time base at 200ms/500ms/1s for each division. The limitation of this scope is that it can only capture at a high rate in these settings. This scope works well, however you will need to take a picture of your pattern and zoom in to see the details. Hey, what do you want for a 130-dollar scope? The Hantek (figure 10) worked well for displaying the secondary ignition ign pattern, but without the custom probe feature, you would have to manually figure out the voltage. However, it worked well when used with primary amp.
Optional Usb Scopes
Going through the options for digital scopes, there seemed to be a few price brackets:
It seemed like a good compromise. I didn’t want to spend too much on it in the event that I wasn’t using it enough. On the other hand, I would probably not immediately be able to buy the I really need to have a better scope soona feeling. PicoTech was my choice after reading reviews and digging through forums.
What Oscilloscope is Best for You?
Update: Added comparison to a professional OBD tool scope facility – Scope C
An oscilloscope is an essential workshop tool. There are many scopes on the market, so how do you choose the best for your application?
The answer is found in the scope’s specifications – that boring list of figures lurking at the back of the scope’s datasheet! Many consumers make buying decisions solely based on the price. Your ability to diagnose problems will be compromised and the return on your investment will be diminished, if an inferior scope is purchased.
Scoppy Pico Uf2 File
You can find all the software needed to run the Pico on a UF2 File, available for download at the Scoppy Website.
Once you have the file on your computer, you’ll need to do the following:
This will create another drive on your computer.
Take the Scoppy UF2 file that you downloaded and copy or drag it into this new drive. Once the file copy has finished, the drive will disappear.
Take a look at your Pico. Installing Scoppy software is successful if the onboard LED flashes at a constant rate.
Installation and Software
For a PC-connected oscilloscope, the software is where most of the action happens, and the hardware is basically just a low-noise, high impedance A/D converter with extremely high sampling rate. PicoScope does triggering based on digitized data, so even that part of the functionality is covered in software.
Setup was very straightforward, just install the PicoScope software and plug the device in. PicoScope was compatible with 64-bit Windows 7, unlike many other devices. PicoScope works in demo mode without the scope. This is a great way to learn the program and get familiar with it. PicoScope was my last oscilloscope. It took me about five minutes to use it. This was fifteen years ago. I found the software intuitive enough that I didn’t need any help.
The picture above shows a measurement of 12 MHz crystal oscillator use in my USB tutorial. Note that this is beyond the specified 10 MHz bandwith, but the wave still renders beautifully. When I put markers to 10 wavelengths it measures 834 ns between the markers, which translates to 11.99 MHz. Not bad! Note that a 1 pixel mistake when placing the markers is larger than the 0,08 % error in this measurement. 🙂
Fft Spectrum Analyzer
The spectrum view plots amplitude against frequency, revealing details that would otherwise be hidden in an oscilloscope view. This view is great for detecting noise, distortion or crosstalk in signals.
Multiple spectrum views can be displayed alongside multiple oscilloscope views. A comprehensive set of automatic frequency-domain measurements can be added to the display, including THD, THD+N, SNR, SINAD and IMD. You can apply a mask limit test to any spectrum. The AWG can also be used together for swept-scalar network analysis.
With PicoScope 2000B models FFTs of up to 1 million points can be computed in milliseconds giving superb frequency resolution. The noise floor can be reduced by increasing the FFT’s number, which can reveal otherwise undiscovered signals.
You can create sine, square and triangle waveforms with the function generator. The AWG lets you import waveforms from files and edit them with the integrated graphical AWG editor.
As well as level, offset and frequency controls, advanced options allow you to sweep over a range of frequencies. Combined with the advanced spectrum mode, with options including peak hold, averaging and linear/log axes, this creates a powerful tool for testing amplifier and filter responses.
Effect On Bandwidth
Analogue to Digital Converters (ADCs) are used by an oscilloscope to convert signals to numbers. ADCs 8 bits are much cheaper and more efficient than ADCs 12 bit. Scope B’s bandwidth is 70MHz, while Scope A and PicoScope 4425A have bandwidths of 20MHz. This analysis was performed using relatively high-speed automotive scopes. We believe that 20MHz is adaquate for most automotive diagnostics. There are scopes available that can display very fast signals, but they have lower bandwidths.
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Scope C also highlights this problem. Scope C has only 100kHz bandwidth, while PicoScope is 200x faster.
OBD tools and system analyzers can be used in conjunction with an oscilloscope. An oscilloscope is not meant to replace them. OBD diagnostic tools and analysers are useful and essential and should be used for early warning of faults, and to reset fault codes and run diagnostics.
In this application note, we have taken some important specifications of the PicoScope 4425A and compared them with two competing 4-channel scopes, Scope A and Scope B, highlighting differences. We hope that this will help you in evaluating any competing scopes to find the one that is best for you.
Topic 3-3: Segmented Buffer
Depending on the settings you have chosen, PicoScope may store more than one waveform in its waveform buffer. When you click the Start button or change a capture setting, PicoScope clears the buffer and then adds a new waveform to it each time the scope device captures data. This continues until the buffer is full or you click the Stop button. You can limit the number of waveforms in the buffer to a number between 1 and 10,000 using the General preferences page. Using this option you can set the scope to trigger on a event, and then it wil record a number of wavelengths. You now can search for abnormalities in the saved buffers.