Recommend to a Friend
Nice job, some issues
4.0
In full disclosure, this is my first digital scope, but after playing with it for several days and putting it through several interesting paces, I understand far more about both the benefits and limitationsof these things in general. I went for the 2-channel 2202E because I can't remember the last time I wished for more than that, and the two channels are nicely backended by the two separate A/D converters for the full 1 Gs/s sampling without any time-splitting like in the 4-channel one. This is discussed in Dave's GDS-2000A teardown/analysis at his eevblog site; the A variant appears to be similar enough to the E series that it was a useful look at the general sign and build quality before even considering a purchase. TEquipment, the seller, was also very responsive to my naive first questions, both on the phone and sent via Amazon's email relay. TEquipment also undersold just about every other vendor on this unit. 200 MHz, two channels, and a pair of probes for less than four digits -- nice to find.
With these scopes, you *must* update the firmware as soon as possible after buying one. The stock sitting at TEquipment and probably every other seller is on firmware version 1.06, which is woefully back-rev. As of this review they're up to 1.24 which fixes quite a few problems with freezes, menu functionality, and features like data-bus decoding. To get the firmware, you'll probably want to bug the US-side guys at instekamerica.com, 909-399-3535, to provide it directly to you. GW Instek insists on this STUPID policy of making customers create yet another login and password to remember at their site to allow firmware downloads, and I have been aking STRONG noises about how they should dispense with all that nonsense and just put the .zip files on their site for unrestricted download. And they need to remember that .RAR is a far less standard file-packaging method, and just stick with tried-and-true .ZIP for *all* their distributions. If/when the support staff get enough direct requests for firmware from customers who REFUSE to "sign up" at their website, they might start to get the idea that the present method is idiotic.
The original firmware locked everything up solid several times before I upgraded, upon innocent enough menu and button actions. The 1.24 release seemed better but may still not fix all of these issues, asafter the upgrade I went through the various self-calibration routines and *those* froze everything up a couple of times until I set the entire mess back to factory defaults, and then made sure to do the calibrations as the *first* thing after power-up. That's just lame, they clearly still have quite a bit of work to do on stability. It is well worth doing the self-calibrations. As the unit came it had several strange DC offsets between different vertical settings, and
getting a fresh calibration from the "traceable" sources is well worth doing after something's been sitting in a warehouse for however long. If you don't have the requisite "length of coax cable" to run between the calibration-output and the channels, hook the two probes together in 1X mode and that seems good enough. The vertical calibration routines use simple DC levels, so frequency response and a little bit of inline resistance/capacitance in probes as opposed to coax doesn't matter.
One of the channel vertical position knobs was pushed too far in on its shaft, defeating the "push to zero" function. Fixed by removing the knob and pushing it back on more gently, but obviously worth checking all the "pushable" knobs for the effects of overzealous assembly workers. We're all hoping the various little encoders will withstand the test of time.
The supplied probes are very cheap-feeling and flakey in a couple of ways. Don't throw away your good ol' Tek or Agilent probes yet, these are *not* replacements for classic well-built ones. The ground rings
at the BNC connectors made unreliable connections when wiggled lightly,
although that problem may have "worked itself out" a little better with
use. The hook clip attachments are rather "microphonic", e.g. they send
big DC *pulses* into the input when tapped on the side. Keep that in
mind when working on anything that may have physical vibration going on.
The stated bandwidth of the 2202E is 200 MHz, e.g. safely one fifth
of the gigahertz sample rate, but there's a generous grey area above
that up to somewhere near the Nyquist frequency where the scope will
still track a signal. I was easily checking some UHF radio outputs
at 469 MHz, albeit with a bit of amplitude aliasing which was quite
understandable once I thought about what was going on.
The CANbus decode seems quite useful -- plugged it into the data bus
on a car and was seeing all kinds of happy packets, which can also
be displayed in tabular data form in an "event table". A long and
deep capture can collect hundreds of packets on an active bus, but
when one tries to save the event table to storage the scope insists
on having an external USB device instead of being able to use its
internal disk, and then only saves 35 or 40 packets out of a couple
of hundred I was seeing on the event-table screen. That's less
useful, as sometimes we *want* a long capture from such buses.
Overall I'm pretty happy with it so far, and I hope GW Instek will
become far more responsive on the firmware issue and get bug-fixes
out and freely available on a regular basis.
Hobbit on
May 11, 2016
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