Vote logic block including running and maintenance overlay in remote control system

Abstract

A voter function block, which can be integrated into a function block diagram programming environment in a process plant control or safety system, implements voter logic in conjunction with providing operational and maintenance overrides which may be set to override individual inputs to the voter function block as well as to override the output of the voter function block. The voter function block, which is easy to create, use, test, debug and document, includes one or input limit detection units which detect if a particular redundant input has reached a specified limit indicating a condition within the process plant, an override unit that may be set by a user to override the consideration of that input in the voting function, a voting logic entity that determines if a trip condition exists based on the values of the valid or non-inhibited inputs, and an inhibit block that may used to override the output of the voter logic block during, for example, a startup or other operational condition. The voter function block may be integrated into a process control or safety system by being communicatively connected to other function blocks, such as to analog or digital input function blocks, analog or digital output function blocks, control function blocks, cause and effect function blocks which implement cause and effect logic, etc. within the process control or safety programming environment.

Description

technical field [0001] The present invention relates generally to process control and safety systems for use in process plants, and more particularly to systems including voting logic with operation and maintenance override functionality. Background technique [0002] Process control systems, like those used in chemical, petroleum, or other processes, typically include one or more process controllers communicatively coupled to at least one host computer or The digital combination is bus or line communicatively coupled to one or more field devices. These field devices can be, for example, valves, valve positioners, switches and transmitters (eg, temperature, pressure, and flow rate sensors) that perform functions within the process device, such as opening or closing valves, and measuring process variables. Process controllers receive signals from field devices representing process measurements and / or other information about the field devices, use this information to implemen...

AI Technical Summary

Problems solved by technology

[0005] While in the past, configuration or safety engineers sometimes manually programmed voting logic into safety system controllers using different programming languages, unfortunately this programming step was tedious, time-consuming and error-prone, which could be serious , because a failure of the safety system to function properly can result in serious injury or death to plant personnel, as well as damage to potentially tens of thousands of dollars worth of equipment and materials in the plant

Images