A Fancy GPIB PSU Front End - Page 1
Forum section: electronics / projects

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: July 12, 2015, 03:04:36 am
content: Doing a little project as a GPIB / VXI PSU Front End. I have a really nice Fluke PM2813 psu, triple outputs but on the back and a tiny 16 characer 1 line LCD screen. Not really meany to be used as a bench psu as such, but these things are awesome and cheap on ebay.So, I have started a little project to make a fancy GUI thats useable that acts as a front end, either over GPIB via USB or GPIB via Ethernet.The plan is to use a raspberry pi in a project box (easy to get full screen graphics out of the thing, and its cheap) with an LCD, I got a nice 7" lcd coming from ebay that does 1024x600. Right now I have it talking over VXI (using ICS gpib to ethernet box) to the PSU and its working nicely and expose the banana connectors + sense to the project box.The software is written that it takes a driver, which basically maps SetVoltage(number) to a gpib command, so PSU that takes SCPI commands can get a driver written up probably fairly easy. The current PM2800 series driver will report number of channels, max voltage per channel and max power per channel, and it knows the PM281x are power curved and PM283x are fixed. Should work with all PM2800 series psu from 1/2/3 channels automatically.I need to work up a keypad for the thing and stick it all in a project box. I've a bit more of a writeup over on one of my blog,http://kråketær.comI've attached what it looks like currently (its not fancy fancy, its just workable right now). It can record data, so I can plot voltage/power etc in fancy graphs.Right now its showing (top 3 lines) actualy voltage/current/power, the next two lines are the set voltage/current and the last line is the overvoltage limit, under that you have some basic info (CC or CV, OCP/OVP, channel on or off, etc)

author: biot
author_rank: Regular Contributor
timestamp: July 24, 2015, 07:23:12 am
content: Hi,I'm a great fan of the PM2800 series myself -- I also have a PM2813, and I love that thing. The worst thing about it is indeed the LCD. I read your blog posts as well.Would you consider using libsigrok to connect to the hardware instead? I wrote a driver (scpi-pps) that supports a ton of programmable power supplies, including the entire PM2800 series. Some advantages:- Much wider support for hardware, and very easy to add new hardware. For example,this commitadds support for the Agilent N5767A.- That driver abstracts out these power supplies into the general sigrok driver model, so you don't have to deal with this "first select channel 1, then enable channel 1" nonsense. It's just a single function call to enable a channel.- You'd get some contributions out of it, since I wouldn't mind a better UI for power supplies either :-)

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: July 24, 2015, 12:16:12 pm
content: I might take a look, I noticed sigrok support PM2800. I pull sigrok git about once a weekI already have it working with vxi over ethernet, waiting to get a NI gpib-usb-hs dongle to do the usb interface but should be super easy.I should poke the libsigrok and see how it does its interface and if it makes vxi/lxi, usb or gpib over pci transparent or not.

author: biot
author_rank: Regular Contributor
timestamp: July 24, 2015, 12:36:08 pm
content: Yup, it does. There's an internal SCPI API that drivers can use, and that abstracts out the actual transport. The driver can specify one, but it does autodiscovery on e.g. USBTMC. Check src/scpi in the libsigrok repo, and how scpi-pps uses it.But that's driver-internal; a libsigrok client just deals with a generic sigrok power supply. That means it would also support non-SCPI devices, and there are quite a few of those.

author: BloodyCactus
author_rank: Frequent Contributor
timestamp: August 11, 2015, 04:06:54 pm
content: just because when it rains it pours, Ive now picked up a PM2811 30V/10A/60W single channel and a PM2812 dual channel 60V/5A/60W, 60V/10A/120W (this one has the jacks underneath it). both shipped for under $100 combined, which is a pretty nice sweet deal. The more I use these the more I really like them.Now that I have three of these fluke branded psu's, Im leaning less to putting jacks on the front of the project box and hooking it to just one PSU, and more to just have the display/keypad, so I can then hook it up to more than one psu (the ics gpib over ethernet lets me hook up to 15 devices together), and just breakout jacks on the front of each psu but control from a central box. Im leaning this way because its how I'm testing it, running the software on my main pc.not entirely sure I want to shift the goal posts yet tho, lol!