KEITHLEY 228/228A - Page 1
Forum section: electronics / testgear

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 16, 2018, 10:00:07 pm
content: This thread will be my repository for my Keithley 228 and Keithley 228A source meter. The first section of this thread is going to look at reproducing the PCB for the input section. Photos "A - S" are of the PCB that is being used to recreate the board. I have started the project in EasyEda and it is "public" so anyone can view, copy, and get them made on their own. The current version, V1, was done in hast and I half-assed it by not designing in the original screw-terminals (thank you bitseeker for parts links and calling it to my attention). I will finish the board shortly and post the link here along with the screw terminals parts links.If I missed anything in the pics below, please let me know and I will fix it. If you have one of these units and my PCB is different than yours, please share pics as well.In the next section of the thread, I will post complete tear down pics and compare the 228 and the 228A side-by-side.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 16, 2018, 10:03:18 pm
content: K-S (forgot about J)

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 17, 2018, 05:54:20 pm
content: The screw terminals for the PCB are here:https://www.mouser.com/ProductDetail/534-1201.(thanks again to bitseeker).I checked the datasheet and used my (cheap) caliper to verify the dimensions:https://www.mouser.com/ds/2/215/201-741482.pdfI ordered 80 terminals to built the 10 PCBs.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 17, 2018, 06:44:46 pm
content: The EasyEda project is here:https://easyeda.com/the18650movement/K228_INPUT. I think I have everything correct. Be sure to check the "attachments" tab for pics and info as well. Because EasyEda automatically generates the solder mask layer, I did not add it to the project. You can click the "Photo View" (camera icon) at the top of the page, you can see a rendering of the finished product. The gerber files are attached in the .zip. Thanks again to Peter for all the help.

author: bitseeker
author_rank: Super Contributor
timestamp: March 17, 2018, 07:15:12 pm
content: Thanks for consolidating everything into the thread. Looking good! It'll be interesting to see if there are any differences between your 228A and mine. I still have to get some new configuration RAM batteries for mine.Quote from: Inverted18650 on March 17, 2018, 06:44:46 pmHow do they know where the card edge area is in order not to solder mask it (and apply the gold fingers)? Do you have to add a rectangle to define it?

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 17, 2018, 09:27:19 pm
content: I used 'pads' for the all the fingers instead of the 'solid area' feature. The 'pads' tool leaves the copper exposed. At checkout, I selected "gold fingers without chamfer." Even though it looked good in the gerber viewer, I probably should go back and add a documents layer to identify the card edge and all the nets that will get the gold layer just to be safe. I will do that now and post Gerber_V3 in a moment.edit:Glad you asked, because I never edited the 'V1' documents layer, which may have caused them confusion...many thanks! I added the notes on the documents layer and in the remarks section of the order form I wrote: "The document layer contains detailed information about the GOLD FINGERS and the CARD EDGE of this PCB." This is my first card edge board so we will see how it turns out and if I need to make corrections, no worries, they get them to me super fast. Total is $2 for 10 boards and that's with the gold fingers added. V3 attached.

author: bitseeker
author_rank: Super Contributor
timestamp: March 17, 2018, 09:45:44 pm
content: I see. This is my first experience with EasyEDA, so I wasn't sure what's the right way to go about it.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 17, 2018, 10:05:40 pm
content: They provide a nice little Gerber Viewer tool as well. Just drag and drop the .ziphttps://gerber-viewer.easyeda.com/I attached pics from the viewer.

author: bitseeker
author_rank: Super Contributor
timestamp: March 17, 2018, 10:18:54 pm
content: Oh, cool. Well, it looks good to me. If anyone else sees anything that needs fixing, speak now.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 18, 2018, 04:54:48 pm
content: I made a few more changes:1.) I was using the "track tool" for the traces from the card edge to the screw post terminals and it gave them the rounded, oblong look, which I didn't like. I went back and used the "solid area tool" and laid the two large tracks coming from the 'OUT +' & 'OUT - ' pads on the bottom of the board. It gave it a cleaner, squared up look.2.) I also changed 'IMON -' & 'IMON + ' to better match the angles of the traces on the OEM board. (may not matter but I did it anyway).3.) The fingers for the card edge are 6.5mm long, not 7.0mm.After I made these changes, I sent it over to the board house. I will shoot some footage when the PCBs arrive. Gerber V4 & pic Bottom_V2 attached.

author: bitseeker
author_rank: Super Contributor
timestamp: March 19, 2018, 03:03:47 am
content: Thanks for the updates. I wasn't a fan of the wide, rounded traces either, but I didn't want to nitpick since it was purely aesthetic. This version does look a lot better. A very nice replica it is.Now that it's off to manufacturing, there are some things about the original board layout that puzzled me.Why does the original have somewhat rounded ends on the main output traces near the sense screw terminals? At first I was thinking it might be for additional creepage distance between output and sense. However, on the back side, the output and sense traces are even closer together.I also found it odd that the sense and monitor terminals have additional traces joining the pads around the slots instead of simply using larger center pads to join them them all together, like on the output terminals.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: March 23, 2018, 01:33:59 pm
content: Peter, those are great questions, but someone smarter than me will have to answer them. I was wondering the same thing. Where are the PCB layout wizards?update: the screw terminals arrived and are a perfect match (thank you Sir!) BUT there was an issue with the PCB. The factory replied stating that I cannot have get JUST gold fingers on the PCB. I must choose the 'ENIG' option at checkout and have the entire board gold plated ( even though they allow you to use the default HASL and select gold fingers for free). I wasted a week trying to sort out the issue with their customer support.I know this is my fault for not already knowing the difference between the two processing options but I was a bit upset that it took a week to sort out. Don't let this happen to you. I have asked the factory to cancel my original order and sent over another request with the correct ENIG processing. The entire board will be gold plated and it will cost $2 per board ($20 plus shipping) instead of $2 for all 10. No worries, happy days.

author: bitseeker
author_rank: Super Contributor
timestamp: March 23, 2018, 06:38:03 pm
content: Quote from: Inverted18650 on March 23, 2018, 01:33:59 pmOh, it was a general question, in case someone knew. Perhaps "PCB" in the thread title would provide the requisite click bait (so to speak), but that would restrict the topic breadth you originally intended.QuoteSo, what was it about the board that triggered the requirement to go ENIG? Was it the large output traces (i.e., not your typical fingers)?QuoteThat's not so bad. I'm not sure if you can still get the boards from Tek/Keithley, but it'd probably cost quite a bit more even after adding in the screw terminals, shipping, etc.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: April 02, 2018, 06:16:02 pm
content: Brief update due to time constraints:The PCBS arrived today. I quickly checked the design to ensure the boards were the same size, shape, and the screw holes were correct. I have two sets. One set is the 'HASL- with Lead' and the other is 'ENIG-RoHS, with Gold Plating'. Screw post terminals fit well.Here are a few pictures. Much more detail plus assembly & test coming soon.

author: bitseeker
author_rank: Super Contributor
timestamp: April 02, 2018, 06:31:37 pm
content: Looking good!

author: LapTop006
author_rank: Unknown
timestamp: August 23, 2018, 04:58:26 am
content: Quote from: Inverted18650 on March 16, 2018, 10:00:07 pmIt's a shame I didn't notice this when it was posted, I picked up a 228 last year and also recreated an output board, I should upload my KiCad files somewhere. They're nice units, although the UX is a bit of a pain.

author: bitseeker
author_rank: Super Contributor
timestamp: August 23, 2018, 05:31:11 am
content: KiCAD files can be imported into a project on EasyEDA, where we did the board discussed in this thread.https://docs.easyeda.com/en/Import/Import-KiCAD/index.htmlOtherwise, you can put them on GitHub or similar.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: November 08, 2018, 05:03:58 pm
content: I would need three of those boards... anybody has some that were build but never used maybe?

author: bitseeker
author_rank: Super Contributor
timestamp: November 08, 2018, 11:56:17 pm
content: Ordinaryman, stand by. I will check later tonight. PM sent.

author: LapTop006
author_rank: Unknown
timestamp: November 09, 2018, 07:22:53 am
content: If bitseeker doesn't, I have spares of mine, but easier is likely share gerbers and get your own boards made, it's probably cheaper than shipping from Australia.

author: bitseeker
author_rank: Super Contributor
timestamp: November 09, 2018, 07:24:07 pm
content: No worries, LapTop006. I got Ordinaryman covered. Thanks for offering to help out. It's one of the many great things about the EEVblog forum/community.How do you connect wires to your board? Solder them directly to the pads?

author: LapTop006
author_rank: Unknown
timestamp: November 09, 2018, 07:46:52 pm
content: Quote from: bitseeker on November 09, 2018, 07:24:07 pmYep, straight onto the pads, they way I don't need to worry about the small clearance below the board.The mechanical holes were done so I can use cable ties for physical retention.

author: bitseeker
author_rank: Super Contributor
timestamp: November 09, 2018, 07:52:18 pm
content: Ah, I was about to ask about those holes, next.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: December 23, 2018, 12:27:28 am
content: Hello all, I am back on the forum and if anyone needs any of these units I have about 12 left. Some are the silver before I figured out how to use the gold finger outline in easyeda. I also have the screw posts, but not the small shorting links for the sense wires; i just cut and drilled so old sheet cooper for those. Reply or message me if you want any, just cover shipping.

author: cncjerry
author_rank: Unknown
timestamp: December 23, 2018, 02:09:27 am
content: Just found your thread. I have an actual input board though I doubt that helps now. It has a clamp on the back making it easier to pull out.I use my 228 for a lot of things, though mostly for charging batteries these days and you can program it to drain the battery then bring it back up at varying current rates.I'll take a couple of boards and will send you a PM.thanks!Jerry

author: Inverted18650
author_rank: Frequent Contributor
timestamp: December 23, 2018, 03:17:20 am
content: I love my 228. (sold the 228A). I also use it for battery diagnostics. I build custom 18650 battery banks and this unit has made my life so much easier. I had to sell the other unit but now am in the market to buy another 228. I found they are easy enought o repair and calibrate and once in spec, they are worth their weight in gold.

author: cncjerry
author_rank: Unknown
timestamp: December 23, 2018, 05:07:32 am
content: If you attach good voltage and current meters to it with GPIB you can monitor the charging current and voltage over GPIB. I use Visual Basic in Visual Studio 2017 Community Edition for all my GPIB code. Much easier to code than Labview. You could probably do peak detect as well but by your ID you look like a Lipo guy.Jerry

author: Inverted18650
author_rank: Frequent Contributor
timestamp: December 23, 2018, 05:33:38 am
content: I only had one GPIB connector and I sold with the 228A a while back. So I haven't had any data logging ( or done anything at all) in the last six months. I just watched "Joe Smith" on YouTube, "joeqsmith" on the forum; his video about the Owon B41T+ and got excited despite his effort to get the bluetooth working a year ago. I just asked the company for a quote on four of the units for my lab to re-investigate the data logging functions. I hope to run those with the 228 and my Fluke 8202 and see what results I can achieve. I built a custom Arduino-based, 50 cell, 18650 test gig that does most of my single cell data and use the Keithley for my pack builds to test my DIY BMS (which i haven't released yet, due to minor set backs).I would love to learn more about the software side of the 228 and if you have the time, maybe you can share the details and some sketchs with me.

author: bitseeker
author_rank: Super Contributor
timestamp: December 25, 2018, 10:42:06 pm
content: Quote from: Inverted18650 on December 23, 2018, 12:27:28 amWelcome back, Inverted.Quote from: Inverted18650 on December 23, 2018, 05:33:38 amWhat made you choose the 228 over the 228A for your lab?QuoteI look forward to seeing more about your experiments with the battery logging and testing.

author: Inverted18650
author_rank: Frequent Contributor
timestamp: December 26, 2018, 05:41:27 am
content: Quote from: cncjerry on December 23, 2018, 05:07:32 amJerry,I am going to take a look at Visual Basic and wonder if you could email me any "sketches" if thats what they are called, for the 228. I did learn and use Labview in conjunction with the K2000 DMM a few times, and while it was initially hard to program, once up and running, it worked well. I am not a "professional engineer,"as it were, I am medically ret mil, so I learn most of this on my own. I do have an entry level degree and still take some courses at the local Univ and online from time to time to enhance it, but I enjoy the "frustration" of doing it the hard way. I thought I would go on and try to get a masters degree but that's not likely now.