Keyboard dot matrix acquisition device and method based on PLC (Programmable Logic Controller)

Abstract

The invention discloses a keyboard dot matrix signal acquisition device based on PLC, which includes a keyboard and a programmable logic controller PLC, and each key signal output interface is respectively connected to at least two different input terminals on the programmable logic controller PLC , the corresponding relationship between each key signal output interface and the connection of the input terminal on the PLC is not the same. In the present invention, each key signal output interface of the keyboard dot matrix is ​​connected with two different input terminals on the programmable logic controller PLC respectively, and the PLC only needs a few input terminals, and multiple output ports of the keyboard dot matrix can be connected to each other. The interface is completely separated to realize the signal acquisition of the keyboard dot matrix. Since the PLC directly detects the input terminal, there is no need to set up an intermediate link of signal transmission such as a single-chip microcomputer, which can effectively avoid signal interference and loss caused by the communication between the single-chip microcomputer and PLC, improve the real-time performance of signal transmission, and effectively reduce costs.

Description

technical field [0001] The invention relates to the communication field, in particular to a PLC-based keyboard dot matrix signal acquisition device. Background technique [0002] The keyboard is the main man-machine dialogue device in electronic products such as computers, mobile phones, and POS machines. Now there are many touch-screen keyboards, which realize the random distribution of keys through programming, but the method of programming is easy to be used by hackers and other tools to steal user privacy. Therefore, in some cases involving high privacy, such as financial , safety, keyboards with physical keys have a wider range of applications. [0003] The logic circuit of the physical button keyboard provides a matrix arrangement of the buttons. Most of the existing matrix keyboard circuits use the I / O port of the single-chip microcomputer to scan the keyboard to control the button part of the keyboard. The existing 4×4 matrix keyboard circuit, such as figure 1 As ...

AI Technical Summary

Problems solved by technology

This method is easy to cause signal interference and loss. In addition, because the input signal scanning method is dot matrix cycle scanning, and then communicates with the PLC through the single-chip microcomputer, it will also be lacking in real-time performance.

Moreover, there are many lines on the actual equipment, the line length is long, and there are many interference sources, which are easy to cause interference to the signal

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