Method for intercontroller communications in a safety instrumented system or a process control system

Abstract

A system provided by the present invention provides a I / O card, which is used to connect two process controllers of a same communication line. The communication line is separated from a main communication line for connecting the two process controllers to a workstation. The process controllers can access the I / O card with the mode being similar to that accessing the I / O card of field devices. After this manner, the physical hardware as well as software structure is used for communication between controllers without alteration. The communication between controllers can be programmed as generalI / O communication.

Description

[0001] This patent is a continuation-in-part of U.S. Application Serial No. 10 / 352,396, filed January 28, 2003, the entire disclosure of which is hereby incorporated by reference this patent. technical field

[0002] The present invention relates generally to process control systems for process plants that use input / output (I / O) devices to provide inter-controller communications. Background technique

[0003] Process control systems—such as those used in chemical, petroleum, or other processes—typically include one or more process controllers communicating with at least one Host or operator workstation and communication link with one or more field devices. The field devices may be valves, valve positioners, switches, and transmitters (such as temperature sensors, pressure sensors, and flow rate sensors) that perform functions in the process equipment, such as opening or closing valves and measuring process parameters. Process controllers receive signals from process measur...

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