Multiple Information Displays

[funfrok]

Hello, Do you know any product that displays screens sent to it through ethernet. It can be an lcd display or a box that you connect to an lcd display/monitor. What i want to do is generate images (or text blocks) in pc software and send screen data to displays through ethernet. I can do it with multiple display adapters and monitors connected to these adapters. But it isn't a flexible solution. Thanks

[paulengr]

I've been looking for the same thing. Don't forget the inexpensive part. I've found three possible approaches. I'm not 100% satisfied with really any of them. To me, the ultimate setup would be a stripped down PC that only runs a web browser accessing a captive web page with minimal extra bells and whistles with VGA or composite video output and that's just about it. First off, multiple display graphics cards from Matrox and not terribly expensive. And if you don't mind using composite video, you can run the cabling a long, long ways. So you can easily have a "multi-headed monster" some place in a room running perhaps 5-10 displays very easily. Other than running all those graphics displays, the PC doesn't really do much, so it works out fairly well. I have successfully taken this approach already. Second, you can get various incarnations of stuff from "ezautomation". This can amount to anything from an HMI to a banner display. And if you look around at the HMI's, some of them are not too badly priced anymore. Just use a PLC to generate the data and feed it through the on board software. In this case I'm not talking about software based HMI's but the hardware ones such as the ones offered by Maple Systems. Third, you can try to buy relatively inexpensive low end PC's. For instance, look around for ones based on ITX motherboards. These are very slow, etc., etc., but they have enough horsepower to for instance load up Linux and boot Firefox off a flash card. That's more than enough horsepower to do whatever you want. Just set the thing up to lock onto a web server and you can pretty creatively do anything you want. Look around the internet for "HTML slideshow" type things for instance. The ultimate in this regard in my mind would be the gumstix processors (google that one too). These are perfect for the application but at least last time I looked, they still don't have decent video output available. As to the monitors...I lean towards "TV's", even the LCD ones without on board tuners. You don't really need the tuner in most cases anyways. The price is significantly less than a comparably priced monitor in most cases. If you want to buy outright PC-style monitors that are already prepackaged, StealthPC seems to be a pretty good source for me. The way that what you are describing is done "commercially" as in with hotels is to distribute the video feed via coaxial cable (75 ohm systems mostly) and to amplify/split the signal as needed. The hardware is much more primitive but it works well if you want to distribute say a dozen or more video images that are all identical to several monitors at once. If you want to take this onto Ethernet, the costs escalate quite a bit. Look around for KVM switches. Several of those manufacturers offer KVM (Keyboard/video/mouse) extenders/splitters that work on CAT 5. Very few offer it that converts to Ethernet (they just use CAT 5 as opposed to coaxial cable out of convenience and cost), since it's pretty much hardware-based technology (no TCP/IP stack). Generally speaking, it seems like you can pay for the cheapest PC's you can get your hands on (ITX motherboard based, Walmart E-Machines, etc.) for less money than what it costs for Ethernet-based KVM equipment. Another approach is "thin clients". Depending on the implementation, many of these are little more than graphics terminals. You could for instance have each one connect via RDP to a Linux server (no reason to pay for Windows-based system) and run whatever software you want remotely via RDP or X terminal software. This is a very flexible approach and can stay easily under $500 per "monitor". You can in some cases replace the OS with an OS of your own choosing as well if you want (Neoware runs Linux so this is fairly easy to do). In fact, the Neoware models (and probably others) have full blown web browsers on board so it should be fairly simple to skip the "remote desktop" server entirely and have a web-only based approach. If you want to do some really cheap and dirty stuff, my plant is riddled with one particular setup. Many of our QC labs have cameras mounted over a table where the lab worksheet/notebook sits, with corresponding video monitors at the operator stations. When the lab techs write down the results from the tests, the operators see it on their video monitors. It's just using cheap surveillance video equipment but it works very well for the purpose. Edited January 29, 2008 by paulengr

[funfrok]

First, thank you very much for such extensive reply Tiny pc's attached to displays, that can display web pages would be the ultimate solution. Problem is i don't have any experience in the field and according to my research online, thin clients aren't very cheap. A tiny pc running linux,firefox with minimum configuration would do the job i think. If i can hook touchpanel lcd to them, it would be super The thing is,20 pc's around production line would worry the maintenance guys i think :)

[paulengr]

Remember...we're talking about the Cyrix processors here (VIA Eden series). No fans. No hard drives. No moving parts. Temperature limits are extended (up to about 150 F). The storage device is a compact flash card or an internal memory. An example is the Neoware E90 running Linux. Although Neoware has been acquired by HP in the last few months (and their web site makeover really, really sucks), list price is $270. Out of the box, this unit runs Firefox (in Kiosk mode) and includes the Java 1.5 engine. It is on the slow side to start up (meaning starting up Java, not the thin client itself) but once running, everything's fine. As to programming web sites...this is fairly simple. Any good book on HTML programming should explain it fairly well. If you want something more advanced, get something on Javascript (such as something published by O'Reilly) and I highly recommend you go to the Dojo Toolkit and download and read their tutorial. It is very, very good and the toolkit itself is top notch. Taking this approach, you can probably just about go a long way towards minimal server support. In this environment, you'd develop a static web page using your choice of "web page development" things. I recommend NVu if you want a pretty good and totally free one. Then you need to instrument it out with the usual scripting using Javascript. Javascript is a bit different from the typical HMI development environment because you develop the web page view almost completely separately from the code instead of embedding the code inside each object for the most part. I believe you can already "Save as HTML" from say Powerpoint. Then it's just a matter of either swiping one of the "slide show" scripts online, using the slide show tutorial from Dojo, or rolling your own. If you want to get into the server side, it really helps to get a good book on Java and JSP pages. You don't need to know Java to use JSP but it really helps. Alternatively you could go the "Ruby on Rails" route which pretty seamlessly lets you develop a working web site without a lot of coding because the Rails system already has a lot of structure embedded in it. If you prefer a more "IDE" (Visual Studio) type of environment, I highly recommend Netbeans. This tends to look much more like traditional IDE programming. The competitor to Netbeans, Eclipse, is also very popular and enjoys some better features in some areas but has a steeper learning curve and suffers from "library mania"...you can only get a truly good system going by downloading and installing dozens of libraries. And the only way to know which ones you truly need and don't, you need to download hundreds and evaluate them all. I prefer the simpler almost all-inclusive approach of Netbeans. Keep in mind here that I'm not really a strong Java fan. But I'm comfortable hacking Javascript and on the server side, Java just makes it so easy.

[scootabug]

Here's my 2 cents (without having read the entire thread, so i may be reiterating someone else's comments)... My first thought is to have thin clients connect to a server via Term Services/RDP (not necessarily THE same server that the HMI runs on...you'll see why in a second). On the HMI 'server' (all or any), I'd write a dirty little dot net app that will take screen dumps with a specific filename in a network shared folder for all of said programs. Following suit, I'd make the clients read the files. Potential issues though are refresh times, cost of thin clients, cost of server with enough seats, having the ability to write the program to dump the screenshots (i reckon you could find a free program to do it). If the programs are all operating on the one system, you probably have to switch between programs to do the screenshots. Might help someone at some stage all the same. Edit: A good free thinclient available called Thinstation would do the shot. It's a basic linux distro, easily customisable, Google for it. Edited April 11, 2008 by imaginemotocondo

[Mike Dyble]

Having read the thread this application is similar to one I was discussing earlier. I got approval yesterday to buy the bits to set up a Red Lion DSP (which has built in web server) and one screen initilaly. If the one screen is success ful then more will be added, together with more DSP's. This is mainly for our plant utilities, we have a DCS system for the main process, but this is already in the process of under going an upgrade, and we cannot therefore hook the Utilities into that now, although we may do so later. So I will be buying a thin client, running linux and probably Firefox, maybe the Neoware offerings suggested in this an my thread. Unfortunately in 'rip off' Britian price is nearer 300 pounds, i.e. 600 dollars, but in terms of UK prices this still competive. So hopefully stuff will ordered Monday, with a view to getting it up and running over the next week or two, as the display is needed urgently owing to some other changes. I will let the forum know how I get on. edit: Just got a quote for 235 pounds for a Neoware E90 Linux thin client still 450 dollars ish, but there we go. HP in the UK were most unhelpfull, dont think they are upto speed with Neoware yet Edited April 11, 2008 by Mike Dyble

[BITS N BYTES]

Would this work? http://www.bb-elec.com/product_family.asp?FamilyId=403

[OkiePC]

We are looking at those to replace our thin clients which have been some trouble to maintain without occasional lock-ups... The Digi Connectport is super fast at rebooting and testing went great as far as improving response times of our RSVewSE clients...but...they don't have a driver for our particular brand of touchscreen and have been unable to create one for us. Our HMI operators gotta have the touchscreen...the keyboard + mouse is not practical for us, but they put up with it for a few days of testing. We only have three of those touchscreens and are considering updating them to one that is already supported by the Digi device. Edited April 14, 2008 by OkiePC

[paulengr]

Maybe I'm missing something here but how is this going to help? Now you will need to have one of these attached to a thin client? It's just a variation on the theme. Except that RDP sucks down the graphics stream while VNC does screen scraping. Plus, since everyone shares the same console with a VNC-type setup (as opposed to RDP which creates separate screens for each user), does this mean you plan on having several thin clients and/or PC's? The best solution I've come up with if thin clients don't work out (and you can't implement everything in a web server) is to go with the "UNO" PC's that B&B is retailing (distributor is Advantech, not sure who the actual manufacturer is). These are about $1000 a piece for a "thin client" like box except with plenty of memory, Windows XP embedded, and boots totally off flash drives. It has no fans or hard drives and has an "industrial" temperature spec.

[OkiePC]

No thin client with the connectport, just multiple sessions on the server, one for each device. It is simply a stripped down version of VNC in a black box that can handle keyboard, mouse (some touchscreens) and a monitor. Ours has USB ports, and I think there are units with PS2 kb and mouse ports. All it needs is power, and an ethernet connection to the server. My experience is limited, my counterpart here has done all the experimenting, and knows the ins and outs much better than I do. I am not sure how much of a burden that would place on a server with 20 of them running at once. I suppose that Digi could tell the OP how much machine he would need to handle 20 display units. I guess it is like a license free "thinner" client, but functionally similar. It is very much like the OP description: "A tiny pc running linux,firefox with minimum configuration" http://www.digi.com/products/zeroclients/c...portdisplay.jsp Paul Edited April 17, 2008 by OkiePC

[paulengr]

How do you have multiple sessions? What's the software side of things? As far as I know, VNC just shows the console. What you've described so far is a thin client with VNC instead of RDP, ICA, or X for the protocol.

[Nathan]

I have a colleague who's created really incredible "industrial marquees" in this fashion with FactoryPMI (you could use any HMI with this technique, but FPMI offers a few specific supporting features that work well here). His approach uses cheap PCs or thin clients to drive the display. If you're using large, high resolution displays (LCD TVs are the best, followed by plasma or projectors) you really want to use a DVI/HDMI input. There are Ethernet based (non-TCP/IP) extension devices, but it's still pretty knarly and expensive at that resolution. Your screens will probably look pretty basic since they're designed to be viewed from afar. You still want to develop them at the native resolution of the display. A cool thing about doing it with FactoryPMI is that you get unlimited client licenses and that the "install-less" Java platform makes it really easy for a basic thin client or cheap PC to run. You just need to figure another $300 or so and a network connection on top of each display. You would then use a table in a centralized database that stores the screen or pre-defined rotation for each computer (marquee). This allows you to centrally control what each monitor displays without messing with remote control software. As a different approach, at work we use NTI brand devices that have video switches that work over Ethernet over Cat 5/6 (again not TCP/IP). It's pretty slick, but expensive and you only get the relatively low resolution DB-15/VGA. There are input and output VGA boxes, both plug into an RJ45 jack. Each computer that you want as an input goes into an input box, each monitor, plasma, LCD, projector goes into an output box. A digital switch allows you to simultaneously map whichever outputs to any input. I think our units support approximately 10 inputs 10 outputs. Here's a $3600 unit that supports 8 inputs and 8 outputs. That unit has all the outputs builtin. The one we use has little Cat 5 extension boxes - I think they're nearly $500 apiece. We do such things with VTCs, Powerpoint slides in multiple languages, and video where the conference may be in different rooms. For your application I would recommend the former approach (centrally controlled individual HMIs driving the displays rather than dealing with video extensions). Edited April 19, 2008 by Nathan