REDUNDANT ANALOG OUTPUT DEVICE

摘要

PROBLEM TO BE SOLVED: To make it possible to quickly and surely detect the abnormality of a current signal and to improve reliability by allowing a normal station to execute self-diagnosis by a signal extracted through an external output extracting resistor and allowing a stand-by station to execute self-diagnosis by a signal extracted through a self-consumption extracting resistor. SOLUTION: Each of microprocessors 20A, 20B has a self-diagnosis function for an external output and a self-diagnosis function for self-consumption in addition to an output data setting function and a master/slave side switching function. An analog output board 30A on the master side executes self-diagnosis for an external-output based upon the value of a signal extracted through a current/voltage converting resistor 22A and an analog output board 30B on the slave side executes self-diagnosis for self-consumption based upon the value of a signal extracted through a current/voltage converting resistor 22B. Consequently the abnormality of a current signal to an object process 14 due to a fault generated in each of two redundant analog output cards 30A, 30B can be quickly and surely detected.