| 摘要 |
<p>Method to provide control redundancy for a process plant control system comprising: providing a control input 305 to a first and second instance of control software sub-system (part of a control application), which process the control input substantially in parallel; and providing either an output of the first or second instance to a process plant field device. The instances can be executed via different control devices, such as control components 310-312, or on the same control device. Control devices can be process plant controllers, processors, central processing units, processor cores, wherein each device is an active controller for one control application. Selection of devices to execute the instances is based on their processing loads and changes over time. The first instance is a master 320 and determines which output 315 is provided to the field device. The input can be provided to a third instance, and the output to be provided to the field device determined by implementing master arbitration schemes, like voting and round robin selection algorithms, on the collected or exchanged outputs from the three instances. In this way a component that has failed can be identified as its output differs from the outputs of the other components.</p> |
