Programmable logic controller and expansion module interface

Abstract

The present invention relates to an interface for programmable logic controllers and expansion modules, and comprises a main module and a plurality of extension modules, the present invention is characterized in that a four-line standard SPI interface wire and two digital logic lines are used: a control line of the bus is interrupted, while the bus for forming the interface of the control line is connected in order; the double-way communication of the main module and all expansion modules are in token-control. In the process of the system initialization, the present invention can automatically complete the address distribution of every expansion module, and can finish the control and double-communication of data and information between the main module and a plurality of expansion modules, and can realize the input, output and functional expansion of a programmable logic controller. The present invention has the advantages that the present invention successfully realizes the communication interface function between the programmable logic controller and the expansion modules, completes the double-way of data and control characters, and has the automatic distribution function of addresses of the expansion modules; in addition, the present invention can effectively solve the conflicts during communication, and can improve the communication efficiency and reliability between the programmable controller as well as the expansion modules.

Description

technical field [0001] The invention belongs to the field of electronic technology, and relates to the interface between a programmable logic controller and a plurality of expansion modules applied in the application field of industrial control. Background technique [0002] With the wide application of programmable logic controllers, a single programmable logic controller cannot meet the requirements in many occasions due to its limited functions. In the actual control process, it is usually necessary to expand the functions of a single controller, that is, by providing other performance Modules, such as input / output analog expansion modules, digital expansion modules, network connection modules, etc., to expand the performance of the system. The modular system can not only be applied to simple systems, but also can be applied to complex systems by expanding the corresponding functional modules. Therefore, the programmable function logic controller needs to provide addition...

AI Technical Summary

Problems solved by technology

This mode greatly reduces the communication efficiency between the main module and the expansion module

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