| 摘要 |
PURPOSE:To attain freely the transmission/reception in terms of data to and from a transmitter such as differential pressure transmitter and electromagnetic flowmeter by changing a current value supplied from a power supply section into an analog signal and superimposing a digital signal on the analog signal to perform transmission/reception. CONSTITUTION:A transmitter Tx controls the current value I supplied from the power supply section PS to two-wire transmission lines L1, L2 into the analog signal, a terminal voltage across a resistor RL inserted in series with the transmission lines drives a display device DP via an A/D converter ADC to receive and display the analog signal value represented by the current value I. On the other hand, a communication equipment CE changes the current value I flowing through the resistor RL into the form of pulse, the value is received by a digital signal at the transmitter Tx, the transmitter Tx changes the current value I in response to the reception and the change is received by the communication equipment CE as a digital signal. |
