Re: [Qscada-developers] Hi all

[wireless <wir...@ta...>]

Jovan Kostovski wrote:
> Hi,
> 
> On 3/19/07, Reza Azizi <azi...@gm...> wrote:
>> OK
>>  as you know there is some limitation on showing real time value on web.
>> because of HTTP limitation. HTTP is a one way protocol.
>> by using ajax we can have more chance to show user, new data.
>> but by making network and web server busy.
> 
> Yes, that's true, the server will be busy. That will depend on the
> number of clients and assuming that the beside the web server for
> serving the ajax hmi, the whole qscada system will work on the same
> machine it can be a problem.
> When I proposed the ajax hmi, I was guided by "no refresh" web page
> not thinking much of the things that are going on behind the scenes.
> Thanks for reminding us about that.
> 
>> for web system i recommend tomcat webserver with JSP for presentation
>> and Servlet for business logic.
>> tomcat work well with mysql and linux.
> 
> I've read some articles on JSP and Java Servlets, but I've never
> worked with them.
> If we can reduce the network load and do some custom graphic drawing
> (for gui components in the hmi representing the parts of the plant),
> why not.
> 
> Can you give us, your vision of a web based hmi?

Yes, Please be more specific. Are you saying to use Java et. al.
for a general purpose HMI? Details of your idea would be
welcome.


> 
>> you say that you are in architectural design phase.
>> it means that your analyze and requirement gathering must be complete.
>> is it true?
> 

The situation is more fluid than than. We all have jobs and
commitments. We decided to create DRAFT documents, base on Paolo's
early work and some discussion among the initial (4) members.


Once the documents are release (currently Jovan is the Lead)
Then we can discuss the architecture and refine the documents.

We just wanted to get some documents together, so we could
begin discussing organization of the work and then as the work
progressed, refine the documents.


We had hoped to get some code working and build some simple control
systems to put up on the net, as a way of attracting attention
and more coders.  We are flexible, but, at the end of the day
decisions have to be made in order for Jovan ( Lead) to focus the work
product.


> Well, basicly we have this two documents listed below and
> the discussions made here on the list.
> 
> http://qscada.sourceforge.net/docs/vd_ps_02_draft.pdf
> http://chombium.awardspace.com/files/qscada/prop01.pdf
> 
> I wanted to put all the things together in one document that
> will describe the whole architecture. At the time this things
> happened we were four: me, Paolo, James and Ian. There
> are also some "want to learn" (sorry for this title ;) ) people
> on the list, that were asking some questions on SCADA systems
> and protocols.
> 
> Since the group is growing I think we shoud hear our new members,
> so, everybody, don't be shy tell us what you think, share with us
> your vision of this project.
> Tell us what do you expect from it and what do you want this project
> to be able to do for you.

OK, I agree with this, but pulling the existing documents together,
parsing and culling ideas, into a single DRAFT would help us focus
on revising the architectural document for another round of
discussion, before we begin coding. So, again, I find myself in
agreement with Jovan.



> 
> BR, Jovan

James

> 
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