Overview of Networked Applications

 PcVue's network capability allows two or more stations to be connected together using a network supporting either TCP/IP or NetBios. When stations are connected in this way, the real time properties (value, status etc.) of identically named variables in the stations can be shared.

The most usual reasons for using networked configurations are:

• Operation. An installation requires several operating stations.
• Application size. The application is simply too large or requires too much processing power to be accommodated on one PC.
• Redundancy. PcVue supports types of multi-station configurations (known as associations) to provide redundancy, that may be used in situations where high availability is essential for ensuring continuous operation.

Stations exchange information by maintaining connections over the network. The station that initiates the connection is known as the client. The station that responds is known as the server. In practice, it is possible for a station to be both client and server, communicating with one or more other stations.

The flow of data between client and server stations is bidirectional. That is to say, a change in the value of a variable in one station will always be reflected by its equivalent variables in all other stations. For example, the server may have a variable with Equipment source linked to a process controller. The variable has been given control attributes, so that a User may change its value and send it to the process controller. The equivalent variable in the client also has the control attribute set. When a User changes the value at the client, the change will be reflected at the server and the value sent to the process controller.

The network architecture is configured from the Networking folder of the Application Explorer. Using the Application Explorer you:

• Define the stations of which the project comprises.
• Define the network connection (known as nodes) for each station.
• Define server associations for redundant application.
• Create the client and server lists used to control the behavior of a number of aspects of PcVue's so that the same project can be used on all stations in a multi-station application.

More information about deployment on a Remote Desktop Session Host (RDS) can be found in the top-level book Deployment.