| 摘要 |
PROBLEM TO BE SOLVED: To automatically detect which of a first sensor and a second sensor is connected, and to automatically perform setting corresponding to the connection mode of the sensor at a rear stage side on the basis of the detection result in a signal input device.SOLUTION: In the connection state of a first sensor A to first and second sensor connection terminals T1 and T2, first circuit state transition means 11a causes a circuit state to transit in accordance with a current difference between off-state currents flowing to the first sensor A in a non-operational state and on-state currents flowing to the first sensor A in an operational state. In the connection state of a second sensor B to second and third sensor connection terminals T2 and T3, second circuit state transition means 11b causes the circuit state to transit in accordance with a current difference between off-state currents flowing to the second sensor B in the non-operational state and on-state currents flowing to the second sensor B in the operational state. The first and second circuit state transition means 11 and 12 are configured such that all the combinations of outputs in two output terminals O1 and O2 in the total four transition states are made different from each other. |
