| 摘要 |
PURPOSE:To allow an input device itself to sample the switching of an external input signal source and to reduce the power consumption and heat generation of an input read stage by providing a digital signal generating circuit with a power feed switch circuit and a timing generating circuit, etc. CONSTITUTION:The power feed switch circuit 11 is interposed between an external common terminal COM connected to the power source 9 of a programmable controller and input terminals B of digital signal generating circuits 101- 116. Further, a latch circuit 12 is provided on the output side of the circuits 101-116 to store output signals. Those circuits 11 and 12 are controlled by a timing signal from the timing signal generating circuit 13 which inputs a clock signal from an oscillation circuit 14. Then, the input device itself samples the switching of the external input signal source to store the output signals of the circuits 101-106 in the circuit 12, reducing the power consumption and heat generation of the input read stage. |
