Process control system using a process control strategy distributed among multiple control elements

Abstract

A process controller implements an overall, user-developed control strategy in a process control network that includes distributed controller and field devices, such as Fieldbus and non-Fieldbus devices. A user defines the control strategy by building a plurality of function blocks and control modules and downloading or installing user-specified portions of the control strategy into the Fieldbus devices and the non-Fieldbus devices. Thereafter, the Fieldbus devices automatically perform the downloaded portions of the overall strategy independently of other portions of the control strategy. For example in a process control system that includes distributed field devices, controllers and workstations, portions of the control strategy downloaded or installed into the field devices operate independently of and in parallel with the control operations of the controllers and the workstations, while other control operations manage the Fieldbus devices and implement other portions of the control strategy.

Description

[0001] This application is related to copending application by Nixon et al., entitled "Process Control System for Monitoring and Displaying Diagnostic Information of Multiple Distributed Devices", filed on even date herewith (attorney docket no. M-3926 US), which application is hereby incorporated by reference in its entirety, including any appendices and references thereto.[0002] This application is related to copending application by Nixon et al., entitled "Process Control System Including Automatic Sensing and Automatic Configuration of Devices", filed on even date herewith (attorney docket no. M-4029 US), which application is hereby incorporated by reference in its entirety, including any appendices and references thereto.[0003] This application is related to copending application by Nixon et al., entitled "A Process Control System User Interface Including Selection of Multiple Control Languages", filed on even date herewith (attorney docket no. M-4045 US), which application is ...

AI Technical Summary

Benefits of technology

[0025] The described process control system and operating method has many advantages. One advantage is that the system supplies a uniform, universal design environment for users of many various expertise, experience and training levels to customize a control process to the physical constraints of the process. A further advantage is that the described system uses control capabilities of various controllers and devices, supplementing these control capabilities when desired and distributing control functionality flexibly throughout the process control system as needed. Another advantage is that the process control system is easily based on a personal computer-based design which is easily implemented within substantially any size process and which is updated by users, without the aid of the control system designer, to perform new and different control functions. This flexibility is achieved by distributing control functions throughout the control system including all central, intermediate and peripheral levels.

Problems solved by technology

The monitoring software programs also signal an alarm when a problem occurs.

These high-level languages, although effective for process control programming, are not usually used or understood by process engineers, maintenance engineers, control engineers, operators and supervisors.

One problem associated with the use of graphical views for process control programming is that existing systems allow only the equipment manufacturer, not a user of this equipment, to create his own control functions, along with associated graphical views, or modify the predefined functions within the provided library.

Clearly, such procedure is very cumbersome, expensive, and time-consuming.

Another problem with existing process control systems is a usage of centralized control, typically employing a central controller in a network, executing a program code that is customized for specialized, user-defined control tasks.

As a result, the process control systems are typically constrained to a particular size and difficult to adapt over time to arising needs.

Similarly, conventional process control systems are inflexible in configuration, often requiring a complete software revision for the entire system when new devices are incorporated.

Furthermore, the conventional process control systems tend to be expensive and usually perform on the functions initially identified by a user or a system designer that are only altered or reprogrammed to perform new functions by an expert who is familiar with the entire control system configuration and programming.

A further problem with existing process control systems is that the physical implementation of different systems is highly variable, including control devices and field devices that have a wide range of "intelligence".

For example, some field devices, such as valves, motors and regulators, may have no computational or control capability.

Still other devices may have some computational strength, but not a sufficient amount to accomplish a desired control task.

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