The safe mechanism and restoring function from abnormality of softwares in the DCS controller system have been studied

and a corresponding algorithm based on the overall situation scanning controller being put forward.When the said controller is in operation under abnormal situation

the said algorithm can timely detect out the abnormality of controller

and restore the controller

at the same time

the abnormal controller can be switched over onto the standby controller

so as to ensure the DCS to be in a safe and stable operation status from beginning to end.The said algorithm can periodically scan and analyse the task of said system

timely despose the abnormality occurred in the process of operation.The said algorithm has been used to FCS165 fieldbus

the longterm test and application in thermal power plants show that the said algorithm boasts higher reliability and safety.