| 摘要 |
PURPOSE:To attain freely the transmission/reception of a data between a transmitter such as of a differential pressure transmitter and of an electromagnetic flowmeter and a communication equipment by transmitting/reception an analog signal and a digital signal and also transmitting a digital signal including the own identification code from a transmitter. CONSTITUTION:Plural transmitters Tx1-Txn control a current value I supplied from power supply sections PS1-PSn to two-wire transmission lines La1, Lb1- Lan, Lbn to form an analog signal. A terminal voltage of a resistor RLn inserted in series with the transmission lines drives a display device DP via an A/D converter to receive and display an analog signal represented by the current value I. On the other hand, a communication equipment CE connected selectively in bridge to the transmission lines changes the current value I into pulse form, transmits the value to a transmitter Txn as a digital signal, the transmitter Txn changes the current value I in response to the receiving and transmits it to the communication equipment CE as a digital signal including the own identification code, and the signal is received. |
