Linking device in a process control system that allows the formation of a control loop having function blocks in a controller and in field devices

Abstract

A system and method for interfacing a plurality of field devices which are communicatively coupled on a communication network via a standard communication protocol with a process control system uses a linking device to seamlessly integrate communications between the field devices and a controller within the process control system. The system and method uses the linking device to emulate the communication characteristics of the field devices to link information in field devices with information in a controller of the control system, thereby allowing control loops to include combinations of function blocks from both the field devices and the controller. The linking device uses a link active schedule to monitor substantially all communications on the communication network connecting the field devices and selectively processes and analyzes the monitored communications. The information processed by the linking device, which may include function block information, is automatically routed from a field device to the controller or from the controller to a field device. Other information, such as field device identification information and/or communications diagnostic information, may be collected by the linking device and sent to a user.