The Design Of Distributed Heterogeneous TMR Safety Control Unit

Distributed heterogeneous TMR (Triple Modular Redundancy) safety control unit, which is based on traditional TMR safety computer, has the character of high security and high reliability. Compared with the traditional security computer, we can set the various safety control units scattered around the field devices and real-time monitor system status by the host computer without affecting the work of the unit. Besides this, the using of POE power supply wiring can greatly simplify the system.In this paper, first, we describe the safety control unit to explain the background of its emergence and existence. Then we analyze the characteristics of various safety computer architectures. Their reliability and safety of the theoretical calculations is also done to prove that the TMR architecture has the highest safety and reliability. Then we have the overall design based on TMR architecture; finish the design of hardware and software, including initialization module, synchronization module, safety communications protocol module and unit data exchange module. At the same time, we complete the host computer software design to achieve the target of real-time monitoring of the TMR unit. Finally, we have a test with distributed heterogeneous TMR safety control unit.