HOT PLUG DEVICE FOR PLC backboard

Abstract

The present invention relates to a hot plug device for a serial backboard, which enables a backboard bus to communicate even if an expansion module fails during communication between a backboard master unit and a backboard slave unit by using a backboard design technique. The hot plug device of the PLC backboard comprises a CPU module used for transmitting an operation command; the at least one expansion module is used for receiving and processing the operation command; the backboard bus is connected to the bus and used for communication between the CPU module and the expansion module; and atleast one backboard module connected to the backboard bus and implemented in a detachable manner that is physically separable from the plurality of extension modules, respectively.

Description

technical field [0001] The present invention relates to a PLC (Programmable Logic Controller, Programmable Logic Controller) backplane (Backplane), in particular, to a hot swap device for an Ethernet-based serial (serial) backplane. Background technique [0002] Backplane technology is a basic technology used to efficiently connect multiple modules to a bus system. [0003] The backplane of a traditional PLC system is used as a data bus to share the data of multiple modules. Even now, the performance of the backplane still determines the overall performance of the system and is an important technology to ensure reliability in data exchange. [0004] figure 1 is a block diagram showing a conventional backplane-based PLC system. [0005] Such as figure 1 As shown, the PLC system based on the backplane includes: a CPU module 10, a backplane master unit 12 is arranged inside the MPU11; a plurality of expansion modules 20a, 20b, 20c, and a backplane slave unit 22 is arranged i...

AI Technical Summary

Problems solved by technology

[0010] At this time, if any one of the plurality of expansion modules connected via the serial backplane bus 30 (for example, the second expansion module 20b) is removed or an internal problem occurs, there is a possibility that communication cannot be performed.

[0011] As mentioned above, if the second expansion module 20b fails to communicate, the first expansion module 20a accepts the command of the backplane main unit 12 and processes it, and then passes through the serial backplane bus 30 to the next second expansion module 20b. The command of the backplane main unit 12 is transmitted, but the second expansion module 20b will not accept the command of the backplane main unit 12

[0012] At the same time, even if the third expansion module 20c in the next stage of the second expansion module 20b can communicate without any problem, it cannot receive commands from the backplane main unit 12 from the second expansion module 20b, resulting in failure to operate normally.

[0013] As mentioned above, if any of the expansion modules connected to the serial backplane bus 30 composed of one bus fails to communicate, the serial backplane bus 30 cannot communicate, so that the communication through the backplane will occur. The problem that the entire PLC system connected to the bus 30 cannot communicate

This problem has a great impact on the reliability of the PLC system

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