| 摘要 |
PURPOSE:To attain an efficient diagnosis by diagnosing the input/output interface circuit of a control device even in the state of not correcting an input/ output device to the control device. CONSTITUTION:When diagnosing a control device 1, an input/output device 2 is disconnected from an input/output interface 3, a diagnosis control output A of a flip flop 15 for controlling the diagnosis is turned into '1' and the output permitting state of loop drivers 16 and 17 is obtained. The output of a driver 11 is looped to the input of a receiver 13 and the output of a driver 12 is looped to the input of a receiver 14, the output information to the drivers 11 and 12 and the input information from the receivers 13 and 14 of a control circuit 10 of the input information and the output information are comparatively checked and thus, the drivers 11 and 12 and the receivers 13 and 14 of the input/output interface circuit can be diagnosed. Since the input/output interface circuit of the control device 1 in the state of not connecting the input/output device 2 like this, the efficient diagnosis can be attained. |
