A multi-tasking strategy combining controls with diagnostics for a control system with duplex processors

Our experiences of implementing a fault tolerant control system is reported. To enhance the reliability, a method for implementing software for the control system with dual structure in processor module is proposed and implemented. By using the multitasking function the overall software for a processor module can be divided into five tasks which includes controls and diagnostics. To achieve the control objective and fault diagnostics effectively the tasks are performed in the dual processor modules, independently. An experimental result shows that the backup processor module can be successfully substituted for the primary processor module when the latter happens to fail, while data relating the failure informations are exchanged continuously via shared memories.<>