| 摘要 |
PURPOSE:To attain data transmission without using an address by reproducing a polling signal for transmission after transmitting a data signal with a higher frequency than that of the polling signal, then transferring the transmission right to the next station. CONSTITUTION:The polling signal transmitted from a primary station 1 is detected by a secondary station 2a. Then high frequency signals different in value of continuing time are transmitted in the form of data signals in response to ON/OFF of a switch 4a of own station. Then the polling signal is reproduced and transmitted. Only data signals are transmitted through an HPF at the next secondary station 2b. The station 2b has the same action as the station 2a after it detects a polling signal. If a certain station has a fault, no data is transmitted from the faulty station and its subsequent stations. Thus the station 1 can know the faulty station. In such a way, the control is possible without setting any address to the secondary station. |
