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A terminal resistance automatic matching system and method for PLC expansion bus

A technology for expanding the bus and terminal resistors, which is applied in the general control system, control/regulation system, electrical program control, etc., to achieve the effect of fast, accurate and automatic matching

Active Publication Date: 2018-07-03
深圳市合信自动化技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the prior art, in a system in which PLCs and expansion modules are cascaded, it is necessary to manually determine which expansion module is the last expansion module, and manually connect the terminal resistor set at the expansion module.

Method used

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  • A terminal resistance automatic matching system and method for PLC expansion bus
  • A terminal resistance automatic matching system and method for PLC expansion bus
  • A terminal resistance automatic matching system and method for PLC expansion bus

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Experimental program
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Embodiment Construction

[0031] Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0032] Such as figure 1 As shown in FIG. 1 , it shows a schematic structural diagram of an embodiment of a terminal resistance automatic matching system of a PLC expansion bus provided by the present invention. In this embodiment, the terminal resistance automatic matching system of the PLC expansion bus includes PLC1 and a plurality of expansion modules 2, and the expansion bus is used for cascade connection between PLC1 and the plurality of expansion modules 2; wherein, in one embodiment, the The expansion bus adopts the MLVDS bus, which belongs to the half-duplex communication of the bus topology. The expansion buses mentioned in the following are all described as the MLVDS expansion bus. It can be understood that in other embodiments, other type of bus. The expansion modules 2 are cascaded. Each expansion module is an independent entity and has n...

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PUM

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Abstract

The invention discloses a terminal resistor automatic matching system of PLC expansion buses. The system comprises a PLC and a plurality of expansion modules. The PLC and the plurality of expansion modules are cascaded through the expansion buses to form a bus topological structure, wherein each expansion module is provided with a frontward bus interface and a backward bus interface, the backward bus interface is provided with a normally-closed switch, and the normally-closed switch is in parallel connection with a normally-closed switch and connects a terminal resistor to the expansion bus; and when a cable is inserted in the backward bus interface, the cable is abutted against the normally-closed switch to enable the normally-closed switch to be open. The invention discloses a corresponding method. By adopting the technical scheme provided by the invention, the terminal resistors can be automatically and rapidly matched.

Description

technical field [0001] The present invention relates to the field of programmable logic controller (Programmable Logic Controller, PLC), in particular to a terminal resistance automatic matching system and method of PLC expansion bus. Background technique [0002] In the prior art, PLC is to expand I / O (Input / Output, input or output) points or functions. Generally, various I / O modules or functional modules need to be connected through an expansion bus to form a PLC control system. The expansion bus communicates with I / O modules or function modules. [0003] Existing PLCs and expansion modules use expansion buses such as serial peripheral interface (serial peripheral interface, SPI) or controller area network bus (Controller Area Network, CAN) for connection and communication. In specific applications, in PLC Before communicating with the expansion module, it is necessary to complete the matching process of the terminal resistor. Among them, the terminal resistance is the r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G05B19/05
CPCG05B19/052G05B2219/1109
Inventor 王精
Owner 深圳市合信自动化技术有限公司