INPUT CIRCUIT FOR SENSOR

PROBLEM TO BE SOLVED: To provide an input circuit for sensor which responds to a current output type sensor and on open collector type sensor, without change of the circuit configuration. SOLUTION: When the input circuit 1 for a sensor is connected to the open collector type sensor S1, a specific point A becomes H level higher than a reference electric potential in a state of the sensor S1 being OFF, and the specific point becomes L level lower than the reference electric potential in a state of the sensor S1 being ON. When the input circuit for a sensor is connected to a current output type sensor, the specific point becomes H level, when the current output from the sensor is large, and becomes L level, when small. Even in cases connected to either of the sensors, a comparator 4 compares the electric potential of the specific point A with the reference electric potential and will output the first level signal, when the electric potential of the specific point A is higher than the reference electric potential, and the second level signal is output, when the electric potential of the specific point A is lower than the reference electric potential. COPYRIGHT: (C)2005,JPO&NCIPI