Multi-node current loop full-duplex communication circuit

Abstract

The invention discloses a multi-node current loop full-duplex communication circuit which comprises first, second and third communication terminals and an intermediate node circuit. The second and third communication terminals are in circuit loop communication with the first communication terminal simultaneously via the intermediate node circuit. The intermediate node circuit comprises a power supply circuit, a sending circuit and a reception circuit, and the power supply circuit receives power provided by the second and third communication terminals, and provides working power for the sending and reception circuits according to a power control signal provided by the third communication terminal. When the first communication terminal sends data, the reception circuit receives current signals from the first communication terminal, converts the current signals, and sends the converted current signals to the second and third communication terminals. When the first communication terminal receives data, the sending circuit converts data, sent by the second and third communication terminals, into current signals, and the current signals are sent to the first communication terminals. The communication circuit is suitable for three-terminal four-wire-system current loop full-duplex communication, and can solve the technical problems that a present circuit tends to be interfered and signals are influenced by voltage drop of the transmission line.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a multi-node four-wire 4-20mA current loop full-duplex communication circuit. Background technique [0002] At present, the commonly used multi-node communication methods usually use voltage signals for transmission, but when long-distance transmission is performed, the transmitted voltage signals are susceptible to noise interference, and the distributed resistance of the transmission line will cause a voltage drop on the voltage signal, and even affect the reception of the receiving end. A technical flaw in the correct judgment of the signal. In order to overcome the above technical problems, multi-node communication can also use current signals for transmission. Different from the voltage signal transmission method, the 4~20mA current loop communication method uses the current signal as the signal representation, that is, 20mA represents the full scale of the sign...

AI Technical Summary

Problems solved by technology

[0005] In view of this, the purpose of the present invention is to provide a multi-node current loop full-duplex communication circuit, which can realize the four-wire 4-20mA current loop full-duplex communication between three communication terminals, and solve the problem that the existing circuit is vulnerable to external Interference, technical issues where signals are affected by transmission line voltage drop

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