I have been handed a rather interesting project as part of a module. The thrust of the project is to post realtime produced cartons from a machine using its plc and then to transfer this data to a web site for remote viewing.

I know that this is the kind of job scada was designed to do but I was wondering if there are other simplier alternatives; no frills so to speak.

I would be obliged if someone could point me in the direction of an online tutorial or other literature to quench my thirst for knowledge.

Thanking you in advance.
-Barry Cahill

 

Have you chosen the PLC yet? If not Siemens has a Ethernet module that they call the CP343-1IT for the S7-300 line and a CP443-1IT for the S7-400 line. This module is web server with already built web pages with built in applets that allow you to display the data in HTML.

http://www.sea.siemens.com/autogen/docs/net/ie/lit/CPs_for_S7.pdf starting on page 9

http://www.sea.siemens.com/autogen/docs/net/ie/lit/Internet Technology.pdf white paper

http://www.sea.siemens.com/autogen/docs/net/ie/lit/Ethernet from IKPI 2000.pdf catalog

Ron Powers

 

Sounds like an application where a PC is a better fit for the module. You're going to need one anyway and the integration would be much easier. If you can find some reliable software.

cww

 

Dear Barry,

Modicon plc's do that automatically.
They have built in webservers that can display
live data from the PLC's.

If you want to just display data then that is the way to go. If you need to have that data being stored then you can use any PLC vendor and
get a SCADA package.

 

opto22 PLC can solve your needs. We are using the same PLC and we are able to see the data in Internet.

 

SIXNET offers several I/O controllers and RTUs that can have a built-in web server. You can use one of these units as an interface to another PLC or you can use them to directly control/monitor your process. For more information:

http://www.sixnetio.com/html_files/ipm_web/ipm_web.htm

 

> The thrust of the project is to post realtime produced cartons from a
> machine using its plc and then to transfer this data to a web site for > remote viewing.

In principle, you have a system in which data flow looks like:

data generation -> data collection -> html generation -> webserver -> web browser

The data generation takes place in the PLC, and the web browser is an element that you should assume is a given, and outside the scope of your implementation task.

There are a number of ways to build such a system.

A. In one approach, each of the remaining 3 steps could be implemented as one or more processes:

1. data collection implemented as a PLC comm module running on a PC, placing collected data into a database.

2. html generation implemented as CGI scripts that generate HTML pages from the database

3. use any readily available web server that supports CGI

B. In another approach, a single process could implement multiple steps:

data collection implemented as a PLC comm module running on a PC that dumps collected data into static HTML pages for the web server to serve (no CGI scripts needed)

or

the CGI programs incorporate the PLC communications; when invoked, they collect the necessary data directly from the PLC and present it in HTML format (no separate data collection process or intermediate database)

or

you incorporate the data collection/formatting directly into the web server, either by implementing a web server plug-in that implements the necessary data collection/formatting, or by building a custom web server that knows how to talk to the PLC and processes custom tags in your web pages.

C. At the extreme end of integrated functionality, you can use a PLC that includes an embedded web server, and which can be outfitted with custom web pages that are dynamically populated with PLC data when requested.

There are advantages and disadvantages to each and every one of these approaches, which can only be evaluated in the context of your project requirements and constraints.

Good Luck,

Greg Goodman
Chiron Consulting