FUNCTION BLOCK APPARATUS FOR VIEWING DATA IN A PROCESS CONTROL SYSTEM

摘要

The present invention is directed to a method of and a device for monitoring, from a central location, the current operating conditions (such as values of process parameters) in a process control network having distributed control functions. In one embodiment, the method and. device of the present invention use schedules periodic communications to send signals containing, for example, measured values of process parameters developed by field devices to a centralized viewing device. The viewing device receives the signals and stores at least one value of the process parameters, and maybe more values if necessary to monitor and control the process. To retrieve the stored process parameters for viewing, the viewing device processes messages from humain interface devices requesting the stored values of one or more of the stored parameters and then transmits response messages containing the stored values. The humain interface device may be the same device as the viewing device, or may be a separate device that communicates with the viewing device using either the same or a different communication protocol as that used by the field devices to communicate with the viewing device. Additionally, the request and response messages may be sent between the devices using unscheduled queued communications.