Agilent Oscilloscope 54622D Logic Analyzer Cable - Page 1
Forum section: electronics / testgear

author: y2khris
author_rank: Contributor
timestamp: May 06, 2016, 04:51:13 pm
content: Hi guys,I've been watching Dave's youtube channel for a long time now and per his review of the 54622D, I've gone and picked one up. I am quite a beginner to the electronics world but I am very interested in learning as much as I can and can use a nudge in the right direction. The oscilloscope works great but I purchased it to be able to use it as a logic analyzer as well because I already have the Rigol DS1102E as a normal oscilloscope. After playing with the scope and using it a little bit, I discovered the logic analyzer portion had a ribbon cable port, much like the ones from our old IDE drives, and looked at the internet for leads and then I saw the $300 price tag and my heart stopped.I have some Arduino projects going on and I'd like to see what is going on with the I2C bus. I went and bought some male-female jumpers and hooked them up to the logic analyzer and to test it, I hooked it into my Arduino's I2C, in line with some of my sensors and the sensors stopped outputting info. I put a 100 ohm resistor between the two and I still had the same issue. I then turned on my Agilent 33120A on a 1KHz square wave and while it does read the square wave, it seems to be made out of hundreds of other, differently sized square waves inside of it. What can I do to make it look like a solid square wave? Is there a nominal voltage that I should be running?I've seen theseeBay auction: #http://www.ebay.com/itm/HP-Agilent-Logic-Analyzer-Cable-16510-61602/161855954291?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D36016%26meid%3D5245fb8b1a2f4426b01a0258c517a04b%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D221268342023and have been thinking of hacking it up but I don't know if it is the right approach. I would like to make this work and create descent logic analyzer test setup for the 54622D, but I don't have the experience to know where to go from here. I don't mind the work as long as I can make this work correctly and have a good setup that will last me a while.

author: Howardlong
author_rank: Super Contributor
timestamp: May 06, 2016, 05:35:33 pm
content: I don't think that's the right cable, I couldn't get your link to work, but based on the part number in he URL it's designed to interface with a board connector.54622D, super scope. Very good for beginners and more, super simple to use, super responsive UI. Boots in five seconds. I still have one, I can see why Dave raved over it. While it lacks serial decode, it does do serial triggering. It's so good, I bought a 54642D too which is basically the same scope but more bandwidth, and used both together for quite some time.When I get back to the lab all being well in a couple of hours I'll get the part number(s) for the LA probe: there are more than one. While you may be able to jury rig something with an IDE cable, there is some jiggery pokery in the cable itself including lossy/resistive coax to improve bandwidth very significantly, maybe two orders of magnitude compared to simple flyng leads, not to mention getting the voltage levels right.

author: y2khris
author_rank: Contributor
timestamp: May 06, 2016, 08:13:44 pm
content: Thanks for the reply. One thing I don't quite have that would be great would be the pinout of the logic analyzer port. If I had the pinout, at least I could begin to figure it out. Do you by chance know which pin controls the clock and/or if the entire upper row is ground?

author: Howardlong
author_rank: Super Contributor
timestamp: May 06, 2016, 08:41:10 pm
content: There is an Agilent pdf somewhere with it on together with a bunch of other logic probes. Apologies, my Friday night imbibement appears to have extended somewhat, so it might be tomorrow unless a less lubricated forum participant can facilitate in the meantime.

author: Someone
author_rank: Super Contributor
timestamp: May 06, 2016, 10:02:46 pm
content: There is an older document "Probing Solutions for Logic Analyzers" which has the pinout and termination requirements for the 40 pin probes.

author: Howardlong
author_rank: Super Contributor
timestamp: May 07, 2016, 06:03:15 am
content: The part numbers to look for are:54620-6160154620-6870154620-61801N2756-60001As far as I can tell, they all relate to the same functioning device, although the last one is a re-model that's shipped with new model MSOs like the 3000T.Make sure you getallthe probe and ground flying leads and grabber clips: on one I purchased on ebay the seller did not disclose that one of the flying leads was missing.The probes provide a 10:1 impedance jump, 100k at the probe and about 10k at the scope, so without the probe the inputs are 10x as sensitive. Maximum voltage a probe tips is +/-40V, or +/-4V at the scope inputs, but if you do jury rig something I would use a series 91k resistor in each probe lead rather than go direct to the IDE connector.

author: y2khris
author_rank: Contributor
timestamp: May 07, 2016, 09:40:21 pm
content: Thank you all for your insight. I will be looking over everything you guys have said and let you know how it goes!

author: Someone
author_rank: Super Contributor
timestamp: May 08, 2016, 01:28:25 am
content: Quote from: Howardlong on May 07, 2016, 06:03:15 amIts not a rigged solution, the actual design for direct attachment is detailed in the document "Probing Solutions for Logic Analyzers".

author: y2khris
author_rank: Contributor
timestamp: May 08, 2016, 03:31:07 am
content: Thank you so much. This is all pure gold! I will be collecting all the parts I need this week. Hopefully it turns into something useful.

author: Howardlong
author_rank: Super Contributor
timestamp: May 08, 2016, 05:09:40 am
content: Quote from: Someone on May 08, 2016, 01:28:25 amSome of that resistance is distributed within the leads in the real cable, that's why a simple lumped component soultion won't match the performance of the real cable.

author: y2khris
author_rank: Contributor
timestamp: June 09, 2016, 07:34:41 pm
content: So I finally had a chance to start working on this project and I ended up picking up an IDS-40 connector, 26 gauge wire and a bunch of 91K resistors. I soldered the wires directly to the connectors and I soldered the 91K resistors in line on the wires at staggered lengths so I don't have a "lumped component solution". I then put heat shrink over the resistor and its solder joints and now I am waiting for my grabbers to arrive. I also need to get a 40 pin cable to extend this one because the way that leads stick out of the side, I would have to force them into the logic analyzer and I'd rather just make it a little longer and keep my cable from getting broken solder joints.I'll put up another update when it is all done. Thank you all so much for all your help.

author: chihaxinh
author_rank: Regular Contributor
timestamp: August 17, 2016, 02:32:13 pm
content: Hi y2khrisI have problem like you, buy osc and seller missing LA cable !Do you have finish diy LA cable and It's working well ?