DEVICE CONSISTING OF A PLURALITY OF UNITS AND ABNORMALITY DETECTING METHOD AND INITIALIZING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To normally return the control of each unit even if a communication error occurs and perform a proper abnormality detection conformed to the characteristic of the unit by changing the criterion of judgment according to the kind of an extended unit when a main body unit judges the normality or abnormality of the extended unit from the communication with the extended unit. SOLUTION: The CPU 117 of a main body 101 transmits a command to each unit 106, 103, and receives the status from each unit 106, 103. The received status is checked for parity error or the like to judge the error. The error counter corresponding to the unit having no error is cleared to 0, and an increment is added to the error counter corresponding to the unit having the error. Whether the error counter exceeds a predetermined prescribed value or not every unit is checked. When the error counter exceeding the prescribed frequency is present, the state of the device is set to a communication abnormal state.