SparkFun Forums

[iceblu3710]

I have been working on a few projects and trying to post as little questions on forums as possible (its to easy to ask for help nowdays) I wanted to figure things out by hand untill I understood it.

One of my projects was just for the fun of it making a remote screen for a chinese digital caliper. I know the data structure (two 24bit serial strings sent a few times a second) but I had to look this information up as my Tectronix 2225 50MHz 2ch analog scope only shows the odd blip on data and its not in the same place each time and when I speed up the time scale all the reads are fuzzy with lines doubling back on themselves. Reading a buffered 20MHz clock looks beautiful but real world data is unreadable. (Scopes pretty old, its had a good life)

So I saw these two bad boys today:

Tektronix 3001 GPX Logic Analyzer:
Pic 1 / Pic 2
HP 54201D Digitizing Oscilloscope:
Pic 1 / Pic 2

Both seem to be in working condition and would be great fun to learn, that logic analyzer itself is quite the piece of hardware. The HP has three 8bit probes but Im not entirely sure it can be used as a standard logic analyzer. But it would be a very good analog scope with a persistent digital front end.

Do you thing this hardware would be worth picking up? In the end I could either get them or say:

Rigol 1052E 50 MHz and the usb logic probe on sparkfuns tools page. The older equipment is much more capable and cheaper than just the Rigol but I want to know if you more experienced guys would pick them up.

Thanks!

[mac]

I renew recently my measure setup (from an old Metrix 530 2x20Mhz scope).

I used to more-than-decent tools at work (Mixed DSO/Logic agilent 5Ga/s, dedicated big logic analysers).

I discard quickly rigol scope, very attractive from the sampling point of view, but the puny screen won't do it for me (agilent has 1025x768 screen, and it's quite hard to switch to 320x220).
Instead I choose an Hantek DSO5200. Not quite the same thing because PC scope are always less handy than full scope. But it's something I could live with at home, certainly not at work.
It was cheaper than direct import rigol, with quite ok features (9bit resolution, 200MSa/s). It comes also with SDK which allows a linux port (no tested), and also automatic measure system. Btw these scopes do not work on USB1.1, at all.

I also have a zerolplus logic analyser, quite impressive for its price. 100MHz sampling, decent memory and protocol decoding plugins (two are free). Protocol decoding is a must-have, as it really make the logic analyser faster to use. [A pity there is no SDK to add specific decoding (AFAIK)] Edit: in fact there is one. Need to have a look at it.

Both are tied to a dedicated old laptop running XP (I mainly use linux at home). So in the end it's quite the same footprint as a normal scope.

About old measure equipements, I went this way back in the 80's. It allows you to have quite good equipement from a fraction of their original price. Be sure to have at least full documentation, and that all parts are working ok.
A must have is a recent calibration/test passed (at least a few years overdue). and do not forget that parts (dedicated probes) are almost impossible to find, so make sure it's complete. For a home use, they should run for years given that these were often made for 24/7 use.

For the chinese caliper, you should look at Shumatech project, as it went recently opensource and it's already cheap and working (I got a DRO-350 for my mill).

[abb51]

mac - that Hantek gear looks OK. How's your experience with it? Software usability, reliability, accuracy etc. Does it live up to its specs re. bandwidth?
(5200 has 80MHz analogue bandwidth and 250MS/s as far as I can tell)
(you can reply in my thread viewtopic.php?t=18548 or via PM if you don't want to spam this thread)


iceblu3710 - if it's in good working order and cheap, I'd go for it. Be sure to check calibration as mentioned. The digital probes with the HP unit may well serve as a 'good enough' logic analyser, saving you even more cash.

[iceblu3710]

I think im gonna try and pick op the HP as I found its manual and the 54201D has these specs:

300MHZ Repetitive Bandwidth
Dual 200 Megasamples/second Digitizers
50MHZ Single Shot Bandwidth
Pre-Trigger Display <---- Handy for the state triggers
A whole lot of maths and compare ability I don't yet understand
24 channels of state triggering
Missing/Extra Bit Triggering Modes <---- No idea what that is

But as a replacement for my aged Textronix 2225 50MHz scope this will be at LEAST as accurate and gives me a persistent display which I really need and solves my need for a logic analyzer (though the HP setup is quite complex but its 3 x 8bits)

It includes all the cables for the logic triggering accesories and thats it but I found the manual and I have 1x & 10x 100MHz probes that should work fine for now.

Anybody care to comment on that Tektronix 3001 GPX Logic Analyzer?? Its a 32bit input spect at some serious speeds. The breakout cable for it is not included but I might be able to pick it up for under a hundred. Could be a fun thing to piece back together and sell to someone who can actually use it.

[mac]

Quite decent specs, I had bad experience of HP at engineering school as we had 1Gh/s equivalent sampling which where in fact ~50MSa/s.

Beware that scope will never compete with logic analyser, unless they have HUGE memory. But digital input like on the HP could be convenient also to add more digital channels (this is how I mainly use the LA function of the agilent).
It's also the same with 1GSa/s scope who have small memory (like rigol), it makes the high samples less attractive.

abb51> I did not have time for testing it in depth (I just got an pcmcia usb2 card last week). I will try to do a short review and test against an agilent at work.

Ps: the only fun thing about some HP scope is the hidden tetris: http://www.eeggs.com/items/28801.html Quite handy in boring school lessons...

[iceblu3710]

Well I bought the scope, cost me a whole $100 but I gotta drive to Washington state in a few weeks to pick it up.

Anyone interested in me uploading a bunch of pics and stuff? If not thanks for the help guys!