| 摘要 |
PURPOSE:To constitute a 2-wire/4-wire converter only with electronic circuits and to insulate the 2-wire and 4-wire electrically, by using a 2-wire/4-wire conversion circuit consisting of electronic circuits and an optical insulation amplifier. CONSTITUTION:A signal from two-wire lines 17, 17' is applied to a 2-wire/4- wire conversion circuit 37 consisting of operational amplifiers 30, 32 and the 4-wire side output signal is applied to an optical insulation amplifying circuit 37. An input signal from a 4-wire lines 19, 19' is applied to an optical insulation amplifying circuit 38, and the output is applied to a 4-wire side input terminal of the 2-wire/4-wire conversion circuit. The monitor current flowing to the two- wire line is picked up at a monitor current absorbing circuit 21 and applied as the power supply for the operational amplifier circuits 30, 32 of the 2-wire/4- wire conversion circuit 29 and operational amplifier circuits 39, 42 of the circuits 37, 38. |
