M
M Griffin
In reply to William Sturm: I've been using SVG in the web browser for HMI, and it seems to work quite nicely. If you are interested in how I did it, I have documented it (including SVG snippets) on my project web site: "http://mblogic.sourceforge.net/mbtools/hmiserver/hmiserverintro-en.html"
That shows examples of how I did push buttons, pilot lights, gauges, strip charts, etc. The nice thing about using SVG is that you aren't limited to whatever "controls" someone provided you. You can make your own custom shapes and animate them the same way. For example, I've used the same technique to animate a tank as I've used to animate a column gauge. Someone sent me a screen shot where they adapted it for a variety of different tanks and hoppers in a dairy (and they were a lot more artistic than my efforts).
> XML is kind of fat, but it very common and open, so it is really best at this point (IMHO). <
JSON is also pretty common for AJAX communications, and it's a lot easier to use and a lot less wordy. It also maps pretty closely to native data structures in Javascript and other languages such as Python, so it doesn't take much effort to parse. Web browsers are starting to support it directly, and there are libraries available for most common languages (it's part of the standard library for some languages).
> I don't think people will used hosted applications for mission critical systems, not yet anyways. <
I was thinking that the vendors might find it attractive for the development software because they would have lots of options for billing you in dozens of different ways. Even if all the technical problems were solved though, I'm pretty sure that I don't like the idea that the vendor could turn off the tap whenever they felt like it.
That's a completely different thing from a web based HMI though. A web based HMI doesn't tie you to a vendor like a hosted app does.
That shows examples of how I did push buttons, pilot lights, gauges, strip charts, etc. The nice thing about using SVG is that you aren't limited to whatever "controls" someone provided you. You can make your own custom shapes and animate them the same way. For example, I've used the same technique to animate a tank as I've used to animate a column gauge. Someone sent me a screen shot where they adapted it for a variety of different tanks and hoppers in a dairy (and they were a lot more artistic than my efforts).
> XML is kind of fat, but it very common and open, so it is really best at this point (IMHO). <
JSON is also pretty common for AJAX communications, and it's a lot easier to use and a lot less wordy. It also maps pretty closely to native data structures in Javascript and other languages such as Python, so it doesn't take much effort to parse. Web browsers are starting to support it directly, and there are libraries available for most common languages (it's part of the standard library for some languages).
> I don't think people will used hosted applications for mission critical systems, not yet anyways. <
I was thinking that the vendors might find it attractive for the development software because they would have lots of options for billing you in dozens of different ways. Even if all the technical problems were solved though, I'm pretty sure that I don't like the idea that the vendor could turn off the tap whenever they felt like it.
That's a completely different thing from a web based HMI though. A web based HMI doesn't tie you to a vendor like a hosted app does.