Data communication device applied in control system

Abstract

The invention relates to the technical field of communication and discloses a data communication device applied in a control system. The device comprises multiple stages of series data reading and writing modules. One data reading and writing module outputs a control signal used for controlling the data transmission direction to the next stage of data reading and writing module; when the control signal is a first level, the data reading and writing module synchronously sends a clock output signal and a data output signal to the next stage of data reading and writing module; when the control signal is a second level, the data reading and writing module sends a clock output signal to the next stage of data reading and writing module, the next stage of data reading and writing module feeds back a clock input signal and a data input signal to the data reading and writing module according to the clock output signal, and the frequency of the clock input signal and the frequency of the clockoutput signal are the same. Therefore, the phase difference between the clock signals and the data signals between the modules in the data transmission process is eliminated, the distance and speed ofdata transmission are increased, and the effect of high-speed data synchronous transmission is achieved.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a data communication device applied in a control system. Background technique [0002] PLC (Programmable Logic Controller, Programmable Logic Controller) control system generally adopts a modular system structure, that is, the daisy chain structure of "PLC + module". The PLC host supports the connection of expansion modules through the backplane bus. The backplane bus is The high-speed data path between the PLC host and the expansion module supports the data communication between the host and the expansion module. [0003] The traditional backplane bus interface uses a synchronous communication interface, but when the speed of this interface is increased to a certain value, misalignment will occur. There are two main reasons for this problem. One is the PLC and the module, the module and the The wiring length between the modules is long, and the wire itself has a transmiss...

AI Technical Summary

Problems solved by technology

[0004] The embodiment of the present invention provides a data communication device applied in the control system, aiming to solve the problems in the prior art that the phase difference between the data and the clock is relatively large during communication, and the indicators such as communication distance and communication rate are difficult to improve

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