CN112527720A - Data communication method applied to rack-mounted plant station terminal - Google Patents

Abstract

The invention discloses a data communication method applied to a rack-mounted plant station terminal, which comprises the following steps: 1) the mainboard application opens the virtual equipment nodes of each channel of each daughter board; 2) writing data into a virtual node through system call by an application, packaging the data with a device address and a channel number into a bus frame by a driver, and inserting the bus frame into a data queue for queuing; 3) the kernel main process checks the queue, if the queue is empty, the queue waits, and if the queue is not empty, the step 4 is carried out; 4) writing the current head node of the queue into an RS485 serial port and broadcasting to each daughter board; 5) the daughter board matched with the broadcast frame identifies and receives the frame; 6) the daughter board sends the multiframe back to the mainboard; 7) after receiving the reply frame, the main board analyzes the data contained in the reply frame into FIFO, and then the step 3 is skipped. The invention creates virtual equipment nodes of each channel of each daughter board in a system layer, realizes bus protocol analysis and communication, enables applications to be concentrated in processing service data, and also saves system resources and performance.

Description

Data communication method applied to rack-mounted plant station terminal

Technical Field

The invention relates to the technical field of computer bus communication, in particular to a data communication method applied to a rack-mounted station terminal.

Background

The station terminal is a terminal device applied to a power plant and a transformer substation, can realize the collection and storage of electric energy meter information and the detection of the operation condition of the electric energy meter, and manages and forwards the collected information. The rack type station terminal is a plug-in board type station terminal which can be installed in a standard screen cabinet of a power plant and a transformer substation, and can flexibly configure various types of acquisition modules and communication modules according to requirements.

For communication of a rack-mounted station terminal, in the prior art, bus protocol analysis is usually realized at an application layer, so that resources are consumed by the application to distinguish physically connected sub-devices, and the application cannot be dedicated to service data processing; moreover, analyzing the bus protocol at the application layer requires that the bottom layer transmits all the data received on the bus to the application layer, which includes the bus protocol unrelated to the service data, and performing a large amount of data memory copy at the application layer inevitably wastes system resources and performance.

Disclosure of Invention

Aiming at the defects and shortcomings of the prior art, the invention provides a data communication method applied to a rack-mounted station terminal, virtual equipment nodes of each channel of each daughter board equipment are established on a system layer, the process of distinguishing physical connection is omitted for mainboard application, the virtual nodes can be directly read and written like reading and writing common serial ports, and the bus protocol analysis and communication are realized.

The purpose of the invention can be realized by the following technical scheme:

a data communication method applied to a rack-mounted plant station terminal comprises the following steps:

step 1: the mainboard application opens the virtual equipment node/dev/ttyVESxx _ x of each channel of each daughter board equipment;

wherein xx is the daughter board address and x is the channel number;

step 2: the mainboard application writes service data into the virtual equipment nodes through write system call, and the kernel layer driver encapsulates the data with equipment node addresses and channel numbers into bus frames and inserts the bus frames into a data queue BusFrameQueue to serve as nodes to queue;

and step 3: checking the queue by the kernel main process BusThread, waiting if the queue is empty, and entering the step 4 if the queue is not empty;

and 4, step 4: writing the current first node of the queue into an RS485 serial port and broadcasting the frame to each daughter board;

and 5: identifying and receiving the broadcast frame by the daughter board matched with the equipment node address and the channel number contained in the broadcast frame;

step 6: the daughter board sends back the multiframe to the mainboard;

and 7: and after the main board receives the reply frame, analyzing the data contained in the reply frame into the FIFO corresponding to the daughter board equipment, and skipping to the step 3.

Further, each virtual device node/dev/ttyvesxxx _ x in the step 1 is created and stored in the system layer.

The invention has the beneficial technical effects that: virtual device nodes of each channel of each daughter board device are created in a system layer, a process of distinguishing physical connection is omitted for mainboard application, the virtual nodes can be directly read and written like reading and writing a common serial port, and bus protocol analysis and communication are achieved, so that application design is simplified, application can be concentrated in processing of service data, memory copy is reduced, and system resources and performance are saved.

Drawings

FIG. 1 is a general flow diagram of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

Examples are given.

As shown in fig. 1, a data communication method applied to a rack-mounted station terminal includes the following steps:

step 1: the mainboard application opens the virtual equipment node/dev/ttyVESxx _ x of each channel of each daughter board equipment; wherein each virtual device node/dev/ttyVESxx _ x is created and stored in a system layer;

wherein xx is the daughter board address and x is the channel number;

step 2: the mainboard application writes service data into the virtual equipment nodes through write system call, and the kernel layer driver encapsulates the data with equipment node addresses and channel numbers into bus frames and inserts the bus frames into a data queue BusFrameQueue to serve as nodes to queue;

the bus protocol designed in the embodiment is as follows:

/*

*Busframeprotocol

*

lead (8bit)0xfe frame preamble

Head (8bit)0xaa frame header

Direction (1 bit)? reply is the data direction of request, 0 is the main board request, 1 is the sub board reply

Reserved (3bit) reservation for extension

Index (4bit) frame sequence number, retry unchanged frame number, retry unchanged

Channel (4bit) channlindex Channel number

Card (4bit) Card address, mainboard 0

Length (8bit) datalength data segment Length

Data (

Check SumL (8bit) CRC-16(Modbus) LowCRC check low byte

Check sum h (8bit) CRC-16(Modbus) HighCRC check byte

Tail (8bit)0x16 frame Tail

*/

And step 3: checking the queue by the kernel main process BusThread, waiting if the queue is empty, and entering the step 4 if the queue is not empty;

and 4, step 4: writing the current first node of the queue into an RS485 serial port and broadcasting the frame to each daughter board;

and 5: identifying and receiving the broadcast frame by the daughter board matched with the equipment node address and the channel number contained in the broadcast frame;

step 6: the daughter board sends back the multiframe to the mainboard;

and 7: and after the main board receives the reply frame, the data contained in the reply frame is analyzed in the FIFO corresponding to the daughter board equipment, and the step 3 is skipped.

The above-mentioned embodiments are illustrative of the specific embodiments of the present invention, and are not restrictive, and those skilled in the relevant art can make various changes and modifications to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention, so that all equivalent technical solutions should be included in the scope of the present invention.

Claims (2)

1. A data communication method applied to a rack-mounted plant station terminal is characterized by comprising the following steps:

step 1: the mainboard application opens the virtual equipment node/dev/ttyVESxx _ x of each channel of each daughter board equipment;

wherein xx is the daughter board address and x is the channel number;

step 2: the mainboard application writes service data into the virtual equipment nodes through write system call, and the kernel layer driver encapsulates the data with equipment node addresses and channel numbers into Bus frames and inserts the Bus Frame Queue of data Queue as nodes for queuing;

and step 3: checking the queue by the Bus Thread of the kernel main process, waiting if the queue is empty, and entering the step 4 if the queue is not empty;

and 4, step 4: writing the current first node of the queue into an RS485 serial port and broadcasting the frame to each daughter board;

and 5: identifying and receiving the broadcast frame by the daughter board matched with the equipment node address and the channel number contained in the broadcast frame;

step 6: the daughter board sends back the multiframe to the mainboard;

and 7: and after the main board receives the reply frame, analyzing the data contained in the reply frame into the FIFO corresponding to the daughter board equipment, and skipping to the step 3.

2. The data communication method applied to the rack-mounted plant station terminal as claimed in claim 1, wherein each virtual device node/dev/ttyVESxx _ x in the step 1 is created and stored in a system layer.

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