Competitive rs-485 bus multi-master communication system and its working method

Abstract

The invention relates to a competitive RS-485 bus multi-master communication system and its working method, which relates to a communication system. At present, the RS-485 bus takes a long time for node data transmission, and it can only detect bus conflicts and cannot actively avoid them. Once a conflict occurs, it needs to re-compete. The present invention includes a plurality of nodes and an interface chip, and is characterized in that: the nodes are provided with an OR gate circuit, a dual-way D-type rising edge trigger, an OR gate circuit, and the output end of the OR gate circuit and the node receiving signal end are connected to the interface chip, A first resistor is set between the positive output terminal of the interface chip and the positive pole of the power supply, and a second resistor is set between the negative output terminal of the interface chip and the ground terminal. This technical solution adopts the hardware conflict detection method, and the bit is the unit. Once a conflict occurs, the failed party will automatically exit, and the party that obtains the control right can continue to send data to ensure that the data is sent correctly this time.

Description

technical field [0001] The present invention relates to a communication system. Background technique [0002] Such as figure 1 As shown, in the traditional RS-485 bus, there is always a unique master node, and other nodes are all slave nodes. Its working process is as figure 2 As shown, the communication is always initiated by the master node. After receiving the command, the slave node obtains the control right of the bus, and then sends information to the bus. After sending, the bus control is returned to the master node. Slave nodes can only send data when inquired by the master node, so emergency data such as alarms cannot be transmitted; slave nodes cannot communicate with each other, and can only be transferred through the master node, which affects the speed. In order to improve node data transmission, a competition mechanism of bus monitoring bus is introduced, and its workflow is as follows image 3 As shown, the bus monitoring bus competition mechanism relies...

AI Technical Summary

Problems solved by technology

It needs to add a software module for node competition in the CPU. Due to the need for software processing and judgment time, the node data transmission time is long, and it can only detect bus conflicts and cannot actively avoid them. Once conflicts occur, communication fails and competition needs to be re-competed

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