QUOTE (italo2008 @ Oct 20 2009, 05:29 AM)

Hi
I need to create an application for windows platform wich allows users supervising a process, in wich there are two or more PLCs. Now, I'm looking for informations about software that I can use in order to create this application (ZenOn, Movicon, ecc.). In the manuals that I found on the Internet, I see that these softwares allow to use ( for example) 2 communication drivers at the same time: but what does it means exactly? does it means that the application will communicate with no more than 2 PLCs?
What kind of hardware do I need in order to establish a communication between PLCs and the PC in wich the application will run? Do I need a particular module on each PLC?
The driver is the software that handles the communication between the HMI software and the PLC. Almost every PLC brand uses a different communication protocol, and many of them use several different ones. The driver software interface has been standardized. The standard is called "OPC". So this allows an HMI to interface to any driver as long as it uses the OPC standard.
The hardware side depends on which communication network standard you choose to use. With most PLC's for maximum flexibility it is usually best to put in communication cards in the PLC that allow it to interface to Ethernet and use standard PC hardware (Ethernet ports), rather than using specialized PC hardware and trying to support the special networks that PLC's offer.