| 摘要 |
PURPOSE:To enable the selection of a slave device with a simple constitution, by connecting a plurality of slave devices with a master controller is series subtracting a specified pulse width signal transmitted from the master controller with a reference pulse width signal of the slave devices at each slave device, and transmitting only the remainting pulse width signal to a succeedig slave device. CONSTITUTION:When a master controller 10 selects the m-th slave device 20m, the said master controller 10 transmits a pulse signal (a) having pulse width (mt) (where; (m) is number of slave devices and (t) is reference pulse width) on a common transmission line 3. On the other hand, the 1st slave device 20a receives a transmitted pulse signal (a) and controls the switching of an AND gate 25 with the reference pulse width (t) determined with a one shot multivibrator 22, then a pulse width signal c passing through this slave device 2a becomes (mt-t). Thus, no signal is generated at an output (h) of the slave device 2a. Thereafter, the pulse width signal is sequentially reduced by the width (t) and a signal of the pulse width (t) is incoming to a slave device (m). Thus, an output K of the AND gate 25 comes to ''0'' and an AND gate 26 is opened, allowing to obtain an output P as ''1'' and to select the slave device (m) only. |
