For example, an application in the process industry might need to monitor the status of several fluid tanks in real time. Each of these tanks might have a device connected to a PLC that measures the level of the tank and inflow and outflow rates. The G2 application developer might model each tank by using a tank object, which is connected to different sensor objects that represent the level, inflow, and outflow, all of which are G2 variables. A PLC bridge can update these variables in real time with data from the PLC. A G2 developer might specify rules that are invoked when the application receives new data points, for example, to trigger an alarm, take corrective action, validate data points, or detect failed sensors.
Applications in the discrete manufacturing industry might be concerned with production counts or statistical measurements such as weight or thickness, which the application uses for statistical process control.
To use any of these bridges, you use general techniques for interfacing with device bridges, as well as specific techniques for your particular bridge.
Each device interface provides a generic bridge knowledge base and examples. Application developers can merge the interface into an existing G2 application. The generic bridge knowledge base provides object definitions for data points and an API to control the bridge.