TH22044A - Three-wire low-power transmitter - Google Patents

Abstract

The invention is a three-wire machine that communicates bi-directional AC signals to and exposes one external device. And will send a DC signal to the second external device The transmitter has a power terminal and a common terminal which is connected to the power and The corresponding common pole of the external power supply.The transmitter includes a detector circuit that is powered by Power and common terminals for providing the machine output. Detectable identification of process parameters (PV) By the detector circuit The communication circuit is energized. From the power terminal and the common terminal and includes the memory storage For transmitter and PV status Communication circuit will receive Detector output knows and will provide a DC signal and AC signal to the signal terminal which is connected to the two external devices, and it will also receive the AC signal from the external device. The first place also, the DC signal shows the detected PV. Throughout the frequency band, which includes the DC and the AC signal is displayed. Digitally to detectable PV and data The transmitter selected by the AC signal received into the media circuit. The substance has an impedance according to the AC characteristic between the signal terminals and the Common polarity on the AC frequency band for receiving and transmitting AC signals to it. To and from the first external device, so that the receiving signal is not cut off and therefore the received signal can be received.The communication circuit has impedance according to the DC characteristic. Between the power and common terminals on a frequency band, including DC And as is typical, it extends roughly to 20 Hz, the characteristic impedance is lower than that of the impedance. Of the second external device, which receives the DC signal significantly, so the accuracy of the DC signal is not compromised. To be in danger In one application, the functions of the first and second external devices can be Get together Will integrate the microcomputer into the communication circuit which will store data News Picture Council The microcomputer will also send and receive. News of the transmitter status as well Width input circuit Of pulses, which encode the DC signal. Will include modems in the media circuit FSK coding substance, detector output Waveforming circuits may also be incorporated, which Will receive and organize the FSK encoded signal that is inserted Affiliated with Communication Standard

Claims (1)

1. Three-wire type transmitter for two-way signal communication. AC to and from devices external to the transmitter and the transmission of the DV signal to it is made up of power and combined terminals that can be connected to power and terminal. Coinciding with Of a power supply outside the transmitter, a sensing device that receives power from the power and common terminals For providing knowledge output showing process parameters (PV) detected by sensing devices, and energized communication devices. From the power terminal and the terminal Including tag: