DEVICE FOR TRACING SPECIFIED DATA FOR UPDATING SECONDARY DATA BASE

摘要

PURPOSE: To enable backup without delay in the case of fault at a 1st-order process controller by providing a device for tracking changes in the prescribed data of a 1st-order data base for the following update of a 2nd-order data base. CONSTITUTION: Between a 1st-order controller 30 and a 2nd-order controller 32, tracking devices 33 and 43 are provided for collecting the prescribed data in data under transfer to a 1st-order memory 32 simultaneously with the transfer to the 1st-order memory 32 and transferring these data to a backup process controller 40 later in order to update a data base for backup. Namely, since only the changed information is caught by the tracking devices 33 and 43 and the 2nd-order data base is updated, the update process can be more frequently executed in real time. Thus, when any fault information occurs, the time required for the 2nd-order controller 40 to succeed the function of the defective 1st-order controller 30 can be shortened to a minimum.