| 摘要 |
PURPOSE:To provide the input port/output port diagnostic device being inexpensive and consisting of a simple constitution, for deciding whether an input port or an output port is normal or abnormal. CONSTITUTION:To each output termianl P1-PN of an output extension I/O port 202 connected to a CPU 200, drivers DV1-DVN are connected, respectively. To each driver DV1-DVN, loads L1-LN and diodes D1-DN are connected in parallel, and also, each diode D1-DN is connected to one input part Pb of the CPU 200. The diodes D1-DN are connected so that the cathode, and the anode become the driver side, and the CPU 200 side, respectively. Also, to the anode of each diode D1-DN, a pull-up resistance R0 is connected. Moreover, the loads L1-LN are connected to the drivers DV1-DVN through diodes D11-D1N, respectively. The diodes D11-D1N are connected so that the anode, and the cathode become the load side, and the driver side, respectively. |
