Method and system for increasing number of RS485 bus hitching devices

Abstract

The invention relates to a method and system for increasing the number of RS485 bus hitched devices, and the method comprises the steps: adding an SYNC synchronization signal line on an RS485 bus, and enabling the devices to be connected with the SYNC synchronization signal line when the devices are hitched on the RS485 bus; and enabling the devices to judge whether devices on the current RS485 bus are in a normal working state or not through an SYNC synchronous signal line, if not, enabling the devices to enter the working state, and otherwise, enabling the devices to enter dormancy again. According to the invention, an SYNC synchronous signal line is combined with a dormancy mechanism, so that the RS485 bus only has one device processing working state at the same moment, the peak power consumption of the system is reduced, and the number of devices capable of being hung on the RS485 bus is greatly increased.

Description

technical field [0001] The invention relates to the technical field of communications, in particular to a method and system for increasing the number of devices connected to an RS485 bus. Background technique [0002] RS485 bus is a low-cost and easy-to-use bus, which adopts half-duplex working mode, supports multi-point data communication, and is widely used in various measurement and control fields. The RS485 bus can theoretically mount up to 400 devices, but it is usually limited by factors such as the driving capability of the RS485 level conversion chip, the impedance matching of the bus, and the power supply capacity of the system. The actual number of devices that can be connected to the bus is often much smaller to the theoretical value. Especially when the power consumption of the device is high and the power supply is centralized, multiple devices work at the same time, the current of the bus is high, and the line loss is large, causing the power supply voltage of...

AI Technical Summary

Problems solved by technology

However, due to the differences in the components of each device, the delay time cannot be consistent. After using the above method, there may still be more than 2 devices working at a certain time after the system has been running for a long time.

Therefore, too many devices cannot be connected to the current RS485 bus

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