| 摘要 |
PURPOSE:To attain the diagnosis of a process output device with loopback of a data to a process input device without connecting again a cable for return test, by switching the data given from a driver receiver circuit to the side of a return test connector from the sieeof a connector for an external device at the side of the process output device with no manual operation. CONSTITUTION:When the abnormality of data is recognized at an external device 7, the information on this abnormality is outputted to a data control circuit 113. The circuit 113 feeds a signal to a connector switch circuit 118. The circuit 118 switches a data line led from a driver receiver circuit 117 to the sid of a loopback, test connector 119 from the side of an external device connector 16 and at the same time sets the circuit 117 under an enable state. The output sent from a process output device 3 is supplied to a process input device 4. Then a CPU 1 diagnoses the input and output data by comparison. |
