Data acquisition system and method for RS485 bus

Abstract

The embodiment of the invention discloses a data acquisition system and method for a RS485 bus. The data acquisition system comprises a host, a first transceiver, a second transceiver and a pluralityof slaves, wherein the host comprises at least one serial port; both the first transceiver and the second transceiver are connected with one serial port; the plurality of slaves are connected in series between the first transceiver and the second transceiver; a communication link formed by the plurality of slaves in the direction from the first transceiver to the second transceiver is preset as amain link; a communication link formed in a direction from the second transceiver to the first transceiver is preset as a standby link; the host is used for acquiring data from each slave through themain link; and when the main link fails, the communication link is switched to the standby link to acquire data of the slaves in the direction from the second transceiver to the first transceiver tilla failure point. The invention also provides a data acquisition method for the RS485 bus. The communication reliability and failure detection accuracy of the RS485 BUS are improved.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a data acquisition system and method of an RS485 bus. Background technique [0002] Currently. In the industrial field, RS485 bus is used for communication, which solves the communication between one master and multiple slaves, and realizes the network communication of multiple devices with few communication lines, but it is limited to the topology characteristics of RS485 bus, and the connection of RS485 bus standard The topology is a hand-in-hand daisy-chain topology. In this case, as long as one of the nodes on the bus is disconnected, the slaves behind the node can no longer communicate with the master. [0003] In order to reduce the risk of circuit breakage, topological structures such as star topology and tree topology are mostly used to avoid them. However, these methods achieve communication stability at the cost of adding a large number of bus connection lines an...

AI Technical Summary

Problems solved by technology

In the industrial field, RS485 bus is used for communication, which solves the communication between one master and multiple slaves, and realizes the network communication of multiple devices with few communication lines, but it is limited to the topological characteristics of RS485 bus and the standard connection of RS485 bus The topology is a hand-in-hand daisy-chain topology. In this case, as long as one of the nodes on the bus is disconnected, the slaves behind the node can no longer communicate with the master.

[0003] In order to reduce the risk of circuit breakage, topological structures such as star topology and tree topology are mostly used to avoid them. However, these methods achieve communication stability at the cost of increasing a large number of bus connection lines and reducing the load capacity of bus slaves, which cannot be guaranteed. Minimum number of communication lines

In addition, due to the use of dual serial port resources on the host side to perform transceiver switching to achieve the purpose of enhancing the reliability of the communication link, it needs to occupy the host dual serial port resources to achieve this, which is not high in resource utilization and cost performance, and in the RS485 bus. The data acquisition system needs to make very complex logical judgments, resulting in a decrease in the efficiency of data acquisition in the communication link

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