RoadTest: PicoScope 6424E Oscilloscope + Accessories
Author: michaelkellett
Creation date:
Evaluation Type: Test Equipment
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: I compared the 6424E with the Rhode and Schwarz RTA4004 and the Keysight MSOX3024T during the course of blogging about the different aspects of the instrument.
What were the biggest problems encountered?: I found the software's treatment of analogue DC offsets applied to the input channels to be rather confusing and very different to standard scope practice.
Detailed Review:
The Picoscope 6424E, like all of Pico's scopes has no screen or front panel controls but is designed to be operated by software running on a PC to which the scope is connected by USB. The 6424E supports and prefers a USB3 Super Speed connection and this is required for maximum performance. As I found out by accident, it works pretty well for most day to day scoping with a USB 2 connection.
The 6424E offers 8, 10 or 12 bit resolution and 500MHz bandwidth on 4 channels and is fitted with a huge amount of memory (4Gbytes). Up to 2 x 8 channel digital pods can be plugged in to make the 6424E into a 4 + 16 mixed signal scope.
Memory and sampling are shared between channels and digital pods so you can only achieve the maximum 5Gs/s rate on two analogue channels at 8 bits resolution, all on (4 analogue and 16 digital) drops you down to 1.25G/s. The interactions are complex - consult the data sheet for details !
The PC software is an important part of the Pico offering and they are busy working on version 7 which I understand will be a big revision and change for version 6 which is current and the version I've tested. I don't have and inside knowledge of version 7 but I'm assuming Pico will stick with their usual practice and offer it as a free upgrade to all Picoscope owners.
I've made an attempt to position the 6424E in the marketplace in the table below. Please don't rely on anything in this table - I don't have the resources to be totally sure that there are no mistakes and it relies on what published information I could find.
I have not compared the 6424E with other USB type scopes, because they are very thin on the ground - Keysight do a version of the MSOX3xxx. It is significant that, in many respects, the 6424E holds its own against much more expensive competition.
The review scope was supplied with Pico's Probe Positioning System and 2 Digital Pods.
The real meat of this Road test is to be found in the following blogs.
Picoscope 6424E RoadTest – Historical perspective.
Picoscope 6424E RoadTest - Probe Positioning System
Picoscope 6424E RoadTest – First Impressions
Picoscope 6424E RoadTest - Testing a power supply
Picoscope 6424E RoadTest - Testing a Transformer
Picoscope 6424E Road Test - SPI Testing with MSO Pods
Picoscope 6424E Road Test - I2C Serial Decoding
Picoscope 6424E Road Test - More decoding and some other stuff
There are several features that did not get a mention in the blogs but are worthy of at least some comment.
The 6424E has a built in signal generator capable of operation up to 50MHz. It can do sweeps but only with linear frequency steps. Pico promote and support a useful third party FOSS Windows application
https://www.picotech.com/library/picoapp/frequency-response-analyzer-with-bode-plots
Currently it does not support the 6000 series scopes - this is an issue that Pico should address with some urgency, all the competition offers some kind of Bode plotting utility and the built in signal generator is of limited use without more software support.
The 6424E offers a persistence mode which is designed to help visualize jitter and anomalies in repetitive signals. I did not explore this in detail.
This is a feature that I can see being very useful in production testing but isn't much called for in the kind of development work that I do. So I shall resort to posting a link to Pico's own discussion of it, in case no one else gives it a good outing !
https://www.picotech.com/library/oscilloscopes/mask-limit-testing
Spectrum mode offers a frequency domain view of the signal. It works a good deal better than the simple FFT modes available on nearly all digital scopes. You can easily measure distortion and signal to noise ratios, within the limits of the scope. (As far as I am aware no scopes have low distortion front ends so are not able to measure good quality audio levels of distortion.) I'm not going to go into a lot of detail on Spectrum Mode, partly because it's a PicoScope 6 software feature, so available on all Picoscopes, and also because I didn't happen to have anything very interesting to look at.
The 6424E internal distortion is about 0.1% or -60dB.
Spectrum mode view of ultra low distortion 2kHz signal (actual 2nd harmonic of oscillator is better than -100dB)
Oscillator disconnected to show 6424E residual noise
Pico offer quite comprehensive support for writing software to access the 6424E, this includes instrument drivers for LabView and MATLAB ans well as a full SDK with support and examples for C++, Python, Linux and Windows.
I'm planning to have a go with the Python when I get time - but that won't be in this Road Test - although I'll blog about it anyway.
I'm not a great fan of assigning numerical scores but it's a Road Test thing, so I have to comply.
In the scoring I do take the cost into account.
So for me, 10 is perfection, no improvement possible - I've never seen a scope that rated 10
Average is 5.
Performed to Expectations, a few things lacking that could easily be improved, but in many ways very good - 8
Specifications Sufficient to Design with, I include documentation in this, pretty good - 7
Demo Software of good quality, I count the Picoscope software in this - it crashed 3 times on Windows 7 (not recommended) and never on Windows 10, many really good features - 8
Product was easy to use, I had to ask about a couple of things and Google quite a bit - it could be made easier - 7
Support materials available, in the end I found material on almost everything I needed but it could have been easier to find and - 7
Price to performance ratio was good - very good - 9
To try and put this into perspective, even at the special offer price (half the list price) my RTA4004 would have scored lower.
The PicosScope 6424E generally behaved very well. The Windows based GUI interface is streets ahead of any built in screen type scope that I have ever used. Far more features are bundled into the package than are offered by the competition (except possibly the higher end LeCroys but you would need to fork out a fortune for add on software).
The Probe Positioning system is very useful.
The supplied scope probes and digital Pods are nicely made and worked well (in the case of the x10 scope probes extremely well considering the price).
Overall value for money is very good.
The 6424E is not quite up with the established scope makers in terms of the analogue channel hardware and the capability of the DC offset system (both in hardware and software ) is its weakest point.
You'll need to read the blogs for details:
I've found that the 6424E has become the scope of first resort in my lab and if I had to choose just one scope to keep and get rid of all the others then it's the 6424E that would stay.
Many thanks to E14 and Pico Technologies for providing and supporting the Road Test programme.
MK
