Programmable logic controller and expansion module interface

Abstract

An interface between a programmable logic controller and an expansion module, comprising a main module and a plurality of expansion modules, characterized in that: a four-wire standard SPI interface line and two digital logic lines are used: an interrupt bus control line and a sequential connection control line It forms an interface bus, and the two-way communication between the main module and all expansion modules is controlled by token type; in the process of system initialization, the address allocation of each expansion module is automatically completed, and the two-way communication of control and data information between the main module and the multi-expansion modules is completed. Programmable controller input and output and function expansion. The beneficial effects of the invention are as follows: the communication interface function between the programmable logic controller and the expansion module is successfully realized, the bidirectional communication between data and control characters is completed, the address of the expansion module is automatically allocated, and the conflict problem in the communication is also effectively solved. , which improves the communication efficiency and reliability between the programmable controller and the expansion module.

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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