Patent ID: 7826935

Claim:
A processing unit comprising: a parameter receiving section which receives a floating-point control parameter generated in a floating-point processor from a detected parameter on the basis of a floating-point calculation, the floating-point control parameter indicating a first quantity of control for a controlled object; a parameter generating section which receives the detected parameter and generates a fixed-point control parameter indicating a second quantity of control for the controlled object from the detected parameter on the basis of a fixed-point calculation; a converting section which converts the floating-point control parameter of floating-point representation into a converted control parameter of fixed-point representation; a failure judging section which judges from comparison between the converted control parameter of fixed-point representation and the fixed-point control parameter whether or not a failure has occurred in the floating-point processor; a signal generating section which generates a control signal from the floating-point control parameter when the failure judging section judges that no failure has occurred in the floating-point processor; and a signal outputting section which outputs the control signal to an actuator such that the actuator is operated according to the control signal so as to give the first quantity of control to the controlled object, wherein the failure judging section has a conversion possibility checking block which judges whether or not the floating-point control parameter of floating-point representation can be expressed by fixed-point data of a predetermined fixed-point representation, and a converting block which performs the conversion when the conversion possibility checking block judges that the floating-point control parameter of floating-point representation can be expressed by fixed-point data.