Pico Automotive has partnered with Garage Wire to answer your PicoScope questions in a new and exclusive GW Views series of question and answer features.
GW readers have the opportunity to get their PicoScope questions answered by Pico Automotive by leaving their questions in the comments below this article or by emailing them to [email protected].
In the first Q&A of the series, Pico Automotive discusses PicoScope options for independent garages.
Question: Which model scope are mechanical shops using and how many channels is recommended?
The PicoScope Automotive range only has two options the 4225 and the 4425 (two and four-channel respectively).
Both devices are identical in specification so there is no compromise on performance, the only difference is the number of channels.
The question “how many channels do I need?” is very common among new scope users and, initially, two channels is certainly sufficient for a beginner.
However, as your scope knowledge increases, the limitations of having only two channels become apparent.
We often measure voltage and current together to confirm circuit/component integrity.
This will of course use two channels on the scope.
Now, imagine that we want to correlate these signals with yet another input in order to identify a sequence (referred to as a synchronisation signal or “sync” for short).
Below is a typical example where three channels give the ability to identify cylinders during a relative compression test.The blue trace, channel A, measures battery voltage during prolonged engine cranking.
The red trace, channel B, captures the ignition trigger event (IGT) from the ignition coil pack on cylinder one.
The green trace, channel C, monitors the current flow through the starter motor – this is directly proportional to the load applied by each cylinder’s compression stroke.
If we zoom, we can use the ignition event (channel B) to synchronise the subsequent compression events, identifying each and every cylinder.
As we can see, the peak current flow into the starter motor during each compression event is uniform, even and repeated across all cylinders.
Here we have, in a non-intrusive way, confirmed that our engine performs as expected during cranking and that our ignition timing for cylinder one is valid at top dead centre (TDC).
Remember we still have a spare channel on our four-channel scope, which in this scenario could be used to monitor the crankshaft sensor for an additional reference.
In a nut shell: while two channels are sufficient, four is desirable and much more practical as your scope knowledge and diagnostic demands increase.
It is worth mentioning that PicoScopes do not have a shelf life.
Automotive PicoScopes sold over 15 years ago are still in use in workshops today, using the current software that is free to download on the Pico website.
Thanks to the continued efforts from the developers on Pico’s software team, the free software updates include new features that were not available 15 years ago.
Technological advancements and existing customer requests keep feeding the drive to evolve further.
As a direct result, a PicoScope purchased today remains future-proof while a PicoScope purchased yesteryear is a better scope today than when originally purchased.
I am not sure how many products, automotive, industrial or domestic, that can pride themselves with such a statement.
You can find more information about the Automotive PicoScope by following the ‘more details’ link below.
GW readers are invited to leave their PicoScope questions in the comments below this article or to send them via email to [email protected].