Communication method based on backboard bus control system

Abstract

The invention relates to a communication method based on a backplane bus control system. The communication method comprises the following steps: setting the initial states of positioning signals of all 485 slave positioning output ports as invalid states; after address allocation is started, a positioning output port of the 485 host is set to be in an effective state; traversing all N slaves, enabling all the slaves to be in a running waiting state, and setting the positioning output port to be in an effective state; the positioning output port of the Nth 485 slave is set to be in an effective state and is connected to the positioning input port of the 485 host for triggering; the 485 host broadcasts a command, and all slaves enter a working state; starting from the first 485 slave, sequentially enabling the serial ports of the next 485 slave, and enabling all the slaves to enter a working state; and the 485 host is communicated with the 485 slave. Compared with the prior art, the slave computer can be addressed through transmission enabling. And the slave computer is automatically subjected to control addressing without hardware configuration and external host control addressing, so that the 485 network addressing stability is high, and the process is simple and reliable.

Description

technical field [0001] The invention relates to the technical field of industrial automatic control, and a backplane bus point-to-point serial communication control system is adopted for one master and multiple slaves based on a transmission stage. Background technique [0002] With the improvement of the level of industrial economic informatization, serial bus has been widely used. Since the common 485 bus adopts the master-slave communication method, each slave node is completely free from other nodes. If two or more nodes send data to the bus at the same time, bus competition will occur, resulting in communication data errors and failure to send. Existing slaves generally need to set the RS-485 slave address through external software or hardware coding switches before accessing the 485 network, resulting in complicated and complicated on-site networking process for the 485 network. The existing communication protocol is complicated in framing, and the frame length is too...

AI Technical Summary

Problems solved by technology

Since the ordinary 485 bus adopts the master-slave communication mode, each slave node is not restricted by other nodes at all. If two or more nodes send data to the bus at the same time, bus competition will occur, resulting in communication data errors and sending failures.

Existing slaves generally need to set the RS-485 slave address through external software or hardware encoding switches before connecting to the 485 network, resulting in a complicated 485 network on-site networking process

The existing communication protocol has complex framing, and the frame length is too long, which affects the communication speed and cannot fully utilize the transmission speed of the 485 bus

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