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US 7,813,820 B2Granted
Method to increase the safety integrity level of a control system
AssigneeABB AB
InventorsAudun Opem, Mats Gunnmarker, Kai Hansen
Life of this patent
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Abstract
Controller capable of executing non-safety-related control logic. A safety module is added to the controller in order to increase the safety-integrity level of a control system. The controller is able to execute safety-related control of real-world objects. Such a control system may exist at an offshore production platform or in a hazardous area of a chemical plant.
Claims18
A method to increase a safety integrity level of a single controller for control of real world objects, the method comprising:
- attaching to the single controller a safety-hardware unit wherein the safety-hardware unit communicates with a central processing unit of the single controller, wherein the safety-hardware unit is used only for safety-critical control,
- connecting a bus to the single controller and connecting an input/output unit to the bus,
- downloading safety-related configuration data and/or diagnostic information to the attached safety-hardware unit and downloading a control function software to the single controller,
- configuring the attached safety-hardware unit to execute logic, which depends on the downloaded safety-related configuration data and/or diagnostic information,
- actively or passively setting output values of the single controller to a safe state for online safety control,
- obtaining access to a plurality of input and output values of a real world object through the bus, and
- verifying a validity of bus communication with the attached safety hardware unit.
4 more elements
A single or 1-channel control system intended for safety-related control of real-world objects, comprising:
- a single main central processing unit handling main processes of a single controller, the single controller comprising a bus configured to obtain access to a plurality of input and output values of a real world object, the single controller further comprising a central processing unit, wherein the single controller is configured to download a control function software, and wherein the single controller is configured such that output values may be actively or passively set to a safe state for online safety control,
- a safety-hardware unit attached to said single controller, the safety-hardware unit comprising means to increase a safety-integrity level of the single controller and comprising means to set output values of the single controller in a safe state for online safety control, wherein the safety-hardware unit communicates with the central processing unit of the single controller, wherein the safety-hardware unit is used only for safety-critical control, herein the safety-hardware unit is configured to download safety-related configuration data and/or diagnostic information, wherein the safety-hardware unit is configured to execute logic that depends on the downloaded safety-related configuration data and/or diagnostic information, and wherein the safety-hardware unit is configured to verify a validity of bus communication, and
- an input/output unit connected to the bus of the single controller.
Dependencies are inferred from the claim text.