CN104796415B - A kind of conversion method between multi-protocols and TCP procotols in RS485 buses - Google Patents

Abstract

The invention relates to a conversion method between multi-protocol and TCP network protocol on the RS485 bus. The downlink communication of this method adopts the RS485 bus to connect with the microprocessor through the RS485 interface, and the uplink communication adopts the microprocessor to access the Internet through the Ethernet interface, and the microprocessor is also connected with NandFlash, SDRAM and SD card, and the hardware for protocol conversion is constructed. platform, and generate a system configuration file in the system through the Ethernet interface, then construct a communication slave station device information table according to the configuration file, and finally use the communication slave station device information table to regularly poll each slave station device on the RS485 bus , and analyze the received protocol data packets, and pack the parsed data into TCP/IP data packets in a certain XML format (in text form) for remote transmission, so as to realize DL/T645‑1997, CJ/T188‑2004 And the conversion between GB/T19582-2008 communication protocol and TCP network protocol. The invention is mainly applied in building energy consumption data collectors.

Description

A conversion method between multi-protocol and TCP network protocol on RS485 bus

technical field

This article involves a conversion method between multi-protocol and TCP network protocol on the RS485 bus, which belongs to the field

field of bus control technology.

Background technique

The field bus is the underlying communication network used in the production and manufacturing field. It realizes the bidirectional serial node digital communication between computerized on-site measurement and control instruments or equipment, and has the characteristics of real-time and high stability. Since the International Electrotechnical Commission (IEC) announced and passed the IEC61158 fieldbus standard in 2000, there are now more than ten fieldbus standards.

Ethernet is a local area network commonly used in the commercial field, combined with the TCP/IP protocol to form the Internet

It has become the de facto standard in network applications, which also makes the fieldbus control system communicate with the national information network through Ethernet

Integration to realize the integration of national monitoring has become the general trend.

DL/T 645-1997 "Communication Protocol for Multi-function Electric Energy Meters" is the tariff rate for the unification and standardization of multi-functional electric energy meters in my country

A power industry standard developed for the physical connection and protocol for data exchange between devices and data terminal equipment.

CJ/T 188-2004 "Technical Conditions for Data Transmission of Household Metering Instruments" is formulated by my country for household metering instruments.

An industry standard, including the basic principles, interface forms and physical

Performance, data link, data identification and data security and data expression format requirements.

The Modbus protocol was originally developed by Modicon and has become the world's most popular general-purpose protocol in the industrial field.

One of the industry standard protocols. In 2008, my country promulgated the national standard GB/T 19582-2008 "Industrial Automation Network Specification Based on Modbus Protocol", and it will be implemented from 2008-09-01.

Currently DL/T 645-1997, CJ/T 188-2004 and GB/T 19582-2008 communication protocols generally adopt the standard

The RS485 communication interface is used as the physical layer transmission mode, the communication baud rate is 1200BPS-115200BPS, and the master-slave half-duplex mode.

According to the "Notice of the State Council on Printing and Distributing the Comprehensive Work Plan for Energy Conservation and Emission Reduction", gradually establish a nationwide network

The energy consumption monitoring platform of office buildings of state organs and large public buildings, the energy consumption of key buildings in key cities across the country (electricity, water,

Gas, heat) for real-time monitoring, which requires the use of energy consumption data collectors to collect data on energy consumption metering devices,

Then upload the collected energy consumption data to the data center (or data transfer station) through the TCP network, and the metering device generally

Adopt DL/T 645-1997, CJ/T 188-2004 and GB/T 19582-2008 communication protocols, at the same time, the energy consumption data collector

A physical interface (RS485 interface) conforming to the industry standard is used between the metering device, which involves the conversion between the above three protocols on the RS485 bus and the TCP network protocol. Therefore, the present invention proposes a protocol on the RS485 bus. The conversion method between multi-protocol and TCP network protocol.

Contents of the invention

The purpose of the invention is to propose a conversion between multi-protocol and TCP network protocol on the RS485 bus

The method realizes the conversion between DL/T645-1997, CJ/T188-2004 and GB/T19582-2008 communication protocols and TCP network protocols. This protocol conversion model mainly adopts the master station model based on the protocol.

In order to achieve the above object, the design of the present invention is as follows:

Generate system configuration files

In a fieldbus-based master-slave communication system, a communication master device is connected via a fieldbus

There are multiple communication slave devices. In the entire master-slave communication system, only the communication master device has the ability to actively initiate communication. The communication slave device receives information from the communication master device and exchanges information with the communication master device. . However, if the communication master device needs to realize the communication with the communication slave device, the communication master device needs to know the address, communication protocol and other information of the communication slave device. Configuration, let the communication master device know the relevant information of the communication slave device connected to the bus, which is convenient for the communication master device to manage the whole system.

Build communication slave device information table

Since the communication between the communication master device and the communication slave device is controlled by the processor software, if the communication master device wants to communicate with the communication slave device, it first needs to read the configuration information of the system through the program to obtain the communication slave device. The address, communication protocol and other relevant information of the station equipment can be initiated before communication.

If the communication master device needs to read the system configuration information every time it initiates communication with the communication slave device, the efficiency of the system will be very low. In order to improve the operating efficiency of the system, according to the read system configuration information, establish A communication slave station device information table, the information table is a structure array, each node of the array records the information of a communication slave station device, the information includes the communication slave station device number, communication slave station device address, communication slave station The protocol type used by the station device, the bus connected to the communication slave device, etc.

Initialize RS485 interface and TCP network

Since the communication on the RS485 bus requires the communication master station equipment and the communication slave station equipment to receive and send data at the same rate, and the communication on the TCP network needs to know the IP address and other information of the destination host, so on the communication master station equipment, it is necessary to pass The read system configuration information initializes the RS485 interface and the TCP network.

Periodic polling of each communication slave device on the RS485 bus and protocol conversion

The communication master station equipment regularly polls each communication slave station device according to the communication slave station device information table, the communication slave station device responds according to the data packet sent by the communication master station device, and the communication master station device receives the response data from the communication slave station device Then, the communication master station equipment analyzes the protocol data according to the information table of the communication slave equipment, and packs the analyzed data into TCP/IP data packets in a certain XML format (in text form) for remote transmission, so as to realize the communication on the RS485 bus Protocol conversion between multi-protocol and TCP network protocol.

According to above-mentioned inventive concept, the present invention adopts following technical scheme:

A conversion method between multi-protocol and TCP network protocol on the RS485 bus, characterized in that: the downlink communication of the method adopts the RS485 bus to connect with the microprocessor through the RS485 interface, and the uplink communication adopts the microprocessor to access through the Ethernet interface Internet, microprocessor is also connected with NandFlash, SDRAM and SD card, has built the hardware platform of protocol conversion, and adopts the communication slave station equipment information table that the present invention provides to regularly poll each slave station equipment on the RS485 bus, and to The received protocol data packets are analyzed, and the analyzed data are packaged into TCP/IP data packets in a certain XML format (in text form) for remote transmission, so as to realize the conversion between the multi-protocol on the RS485 bus and the TCP network protocol.

The specific steps of the above-mentioned protocol conversion are as follows:

(1) Microprocessor initialization;

(2) Operating system initialization;

(3) Generate system configuration files through the Ethernet interface;

(4) Construct a communication slave station device information table according to the configuration file in step (3);

(5) Initialize the RS485 interface and TCP network respectively according to the configuration file in step (3);

(6) According to the communication slave device information table in step (4), periodically poll each slave station device on the RS485 bus through the RS485 bus, and analyze the received protocol data, and finally convert the parsed data into a certain XML format (in text form) packaged into TCP/IP data packets for remote transmission, so as to realize the conversion between the multi-protocol on the RS485 bus and the TCP network protocol.

The specific method of generating the system configuration file in the step (3): write the device number, device address, protocol type and other information of each communication slave device connected to the communication master device into the system through the form of embedded Web In an XML file in , a system configuration file is generated.

The communication slave station device information table in the step (4) is a linked list (or array) of structure type, and each node of the linked list (or array) records the relevant information of a communication slave station device, which includes communication The RS485 port to which the slave device is connected, the type of the communication slave device, the protocol used by the communication slave device, and the device number of the communication slave device.

The specific method of conversion between the multi-protocol on the RS485 bus and the TCP network protocol in the step (6) is:

1) Set the timer according to the system configuration file;

2) After the timing time is up, the communication master device polls each communication slave device in turn according to the relevant information of the communication slave device connected to the RS485 bus recorded in the communication slave device information table;

3) Receive the protocol data of the communication slave device, and analyze the protocol data according to the device information in the information table;

4) Pack the parsed data into a TCP/IP packet in a certain XML format (in text form)

Perform remote transmission to realize the conversion between multi-protocol and TCP network protocol on the RS485 bus.

The above-mentioned system configuration file includes the device number, device address, protocol type and the IP address of the data remote transmission host of the Ethernet interface on the communication slave station device on the RS485 bus; the communication slave station device information table is based on the system configuration file The generated information in the communication slave station device information table corresponds to the communication slave station devices connected to the RS485 bus.

According to the above-mentioned protocol conversion method, data of multiple protocols are allowed to be transmitted on the same RS485 bus: DL/T645-1997, CJ/T188-2004 and GB/T19582-2008 communication protocols.

In the above-mentioned protocol conversion method, through the communication slave station equipment information table, the communication master station device can perform unified management on each communication slave station device; the communication master station device can determine the device number that sends the protocol data according to the address of the protocol data , and then by consulting the communication slave station equipment information table, the protocol type used by the protocol data can be obtained.

Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant advantages:

The invention builds a hardware platform for converting DL/T645-1997, CJ/T188-2004, GB/T19582-2008 and TCP network protocol on the RS485 bus, builds a communication slave station equipment information table according to the system configuration file, and then Use the communication slave station device information table to periodically poll each slave station device on the RS485 bus, and analyze the received protocol data packet, and finally pack the parsed data into a TCP/ IP data packets are transmitted remotely to realize the conversion between DL/T645-1997, CJ/T188-2004 and GB/T19582-2008 communication protocols and TCP network protocols.

Description of drawings

Fig. 1 is a hardware block diagram of an embodiment of the present invention.

Fig. 2 is a main program block diagram of the embodiment of the present invention.

Fig. 3 is a communication slave station device information table according to the embodiment of the present invention.

Fig. 4 is a program block diagram of protocol conversion in the embodiment of the present invention.

Detailed ways

Preferred embodiments of the present invention are described in detail as follows in conjunction with accompanying drawings:

Embodiment one:

Referring to Fig. 1, the conversion method between the multi-protocol on the RS485 bus and the TCP network protocol downlink communication adopts

The RS485 bus is connected to the microprocessor through the RS485 interface, and the upstream communication uses the microprocessor to connect to the Internet through the Ethernet interface. The following communication slave station equipment information table realizes the conversion between DL/T645-1997, CJ/T188-2004 and GB/T19582-2008 communication protocols and TCP network protocols: Generate system configuration files in the system through the Ethernet interface , and then construct a communication slave station device information table according to the configuration file, and finally use the communication slave station device information table to regularly poll each slave station device on the RS485 bus, and analyze the received protocol data packet, and get The data is packaged into TCP/IP packets in a certain XML format (in text form) for remote transmission.

Embodiment two:

This embodiment is basically the same as Embodiment 1, and the special features are as follows:

Described system configuration file comprises the equipment serial number of the communication slave station equipment on the RS485 bus line, equipment address,

Protocol type and the IP address of the data far-transmission host computer of Ethernet interface; The described communication slave station device information table is generated according to the system configuration file, and the information in the communication slave station device information table is connected with the communication slave station connected on the RS485 bus One-to-one correspondence between devices. On the same RS485 bus, it is allowed to transmit data of multiple protocols: DL/T645-1997, CJ/T188-2004 and GB/T19582-2008 communication protocols. The communication slave station equipment information table, through this table, the communication master station equipment can carry out unified management to each communication slave station equipment; The communication master station equipment can judge the equipment number that sends the protocol data according to the address of the protocol data, and then The protocol type used by the protocol data can be obtained by consulting the communication slave station device information table.

Embodiment three:

Referring to Fig. 2, the conversion method between the multi-protocol and the TCP network protocol on the RS485 bus concrete operation steps:

1. Microprocessor initialization;

2. Operating system initialization;

3. Generate system configuration files through the Ethernet interface;

In order to let the communication master device set know the address of the communication slave device, the communication protocol and the TCP network

When transferring information such as the IP address of the destination host, it is necessary to configure the entire system through the communication master station equipment. Here, the system configuration information (communication slave station device number, communication slave station device address, protocol type used by the communication slave station device, bus connected to the communication slave station device, and TCP communication purpose host IP, etc.) into an XML file. Among them, the format of the XML file is:

<?xml version="1.0" encoding="utf-8" ?>

<config>

<common>

<gateway_id>08</gateway_id>

<socket port=”5000”>59.79.2.35</socket>

</common>

<RS485_0>

<meter id="0001" type="10" protocol="1">01020304050607</meter>

<meter id="0002" type="30" protocol="2">01020304050608</meter>

</RS485_0>

<RS485_1>

<meter id="0003" type="40" protocol="3">01020304050609</meter>

</RS485_1>

</config>

Among them, "59.79.2.35" represents the IP address of the data center (or data transfer station), id represents the communication slave device number, type represents the communication slave device type, protocol represents the communication protocol used by the communication slave device, "01020304050607 "Represents the address of the communication slave device.

4. Build communication slave device information table

Since the communication between the communication master device and the communication slave device is realized by the control of the processor software, the communication

In order for the master device to communicate with the communication slave device, it first needs to read the configuration information of the system through the program to obtain the communication slave device.

Station device address, communication protocol and other related information, and then, according to the read system configuration information, establish a communication slave station

Device information table, which is a structure array: struct meter Dev[SIZE] (SIZE is the number of communication slave devices actually connected to the RS485 bus), each node of the array records a communication slave station The information of the device, the information includes the communication slave device number, the communication slave device address, the protocol type used by the communication slave device, the bus connected to the communication slave device, etc., see Figure 3. Among them, the structure is:

struct meter {

char num[5];//Slave device number

char port;//RS485 bus connected to the slave device

char protocol;//The protocol type used by the slave device

char metertype;//Slave station device type

unsigned char addr[7];//slave device address

};

Among them, protocol is the protocol type used by the slave device:

0x01: DL/T645-1997 protocol

0x02: CJ/T188-2004 protocol

0x03: GB/T19582-2008 protocol

5. Initialize the RS485 interface and TCP network respectively according to the read system configuration information;

6. Periodically poll each communication slave station equipment

The communication master station device queries the communication slave station device information table, determines the communication protocol and address and other related information used by each communication slave station device, and then regularly polls each communication slave station device, and each communication slave station device sends out the information according to the communication master station device. The request data packet responds, and the communication master device receives the response data packet from the communication slave device. The specific communication process is shown in Figure 4.

7. Protocol Conversion

According to the communication protocol used by the communication slave device, the communication master station device analyzes the protocol data packet of the communication slave station device, and extracts information such as power consumption, water consumption or heating and cooling capacity from the data packet, and then the communication master station device will Information such as slave station device address, energy consumption type and power consumption (or water consumption, heating and cooling capacity) is packaged into TCP/IP data packets in a certain XML format (in text form) for remote transmission, so as to realize communication on the RS485 bus Conversion between multi-protocol (DL/T645-1997 protocol, CJ/T188-2004 protocol and GB/T19582-2008 protocol) and TCP network protocol. For the XML format, please refer to the "Technical Guidelines for Transmission of Sub-item Energy Consumption Data Transmission of the Energy Consumption Monitoring System of State Organs' Office Buildings and Large Public Buildings". The specific XML format is:

<?xml version="1.0" encoding="utf-8" ?>

<root>

<!-- General part -->

<!--

building_id: building number

gateway_id: master device number

type: the type of remote data packet

-->

<common>

<building_id>XXXXXX</building_id>

<gateway_id>XXX</gateway_id>

<type>report</type>

</common>

<!-- Data remote transmission -->

<!--

There are 5 types of elements

sequence element: the serial number of the data sent by the collector to the server

parser element: whether the data sent to the server has been parsed by the collector

time element: data collection time

meter element: the device number of the slave device, with an id attribute

function element: the specific function of each slave device, with the following three attributes,

id attribute: the function number of the slave station device (for use by the multi-function electric energy meter)

coding attribute: energy consumption data classification/sub-item coding

error attribute: the error status code of this function, 0 means no error

-->

<data operation="reply">

<sequence>XXXXXXXX</sequence>

<parser>yes/no</parser>

<time>YYYYMMDDHHMMSS</time>

<meter id="1">

<function id="1" coding="XXX" error="XXX">Data 1</function>

</meter>

<meter id="2">

<function id="1" coding="XXX" error="XXX">Data 1</function>

</meter>

</data>

</root>

Claims (6)

1. the conversion method between multi-protocols and TCP procotols in a kind of RS485 buses, it is characterised in that：Downlink communication It is connect with microprocessor by RS485 interfaces using RS485 buses, uplink communication is connect using microprocessor by Ethernet interface Enter internet, microprocessor is also associated with NandFlash, SDRAM and SD card, has built the hardware platform of protocol conversion, tool Body implementation steps are as follows：

(1) microprocesser initialization；

(2) operating system initialization；

(3) system configuration file is generated by Ethernet interface；

(4) a communication slave station equipment information table is built according to the configuration file of step (3)；

(5) RS485 interfaces and TCP networks are initialized according to the configuration file of step (3) respectively；

(6) each slave station in RS485 bus timing poll RS485 buses is passed through from facility information table according to the communication of step (4) Equipment, and the protocol data of reception is parsed, the data for finally obtaining parsing are with certain XML format --- with text Form is packaged into TCP/IP data packets and carries out teletransmission, to realize between the multi-protocols in RS485 buses and TCP procotols Conversion；

1) according to system configuration file, timer is set；

2) after timing arrives, communication main station equipment is connected according in the RS485 buses recorded in communication slave station equipment information table The relevant information of slave station equipment is communicated, successively each communication slave station equipment of poll；

3) protocol data for receiving communication slave station equipment, according to the facility information analysis protocol data in information table.

2. the conversion method between multi-protocols and TCP procotols in RS485 buses as described in claim 1, feature It is：The specific method of generation system configuration file in the step (3)：It will be connected to by the form of embedded Web logical The information such as device numbering, device address, the protocol type of each communication slave station equipment of letter master device are written to one in system In a XML file, to generate a system configuration file.

3. the conversion method between multi-protocols and TCP procotols in RS485 buses as described in claim 1, feature It is：Communication slave station equipment information table in the step (4) is the chained list or array of a structure type, the chained list or number The relevant information of one communication slave station equipment of each nodes records of group, these information include that communication slave station equipment is connected The ports RS485, communication slave station equipment type, the used agreement of communication slave station equipment and communication slave station equipment device number.

4. the conversion method between multi-protocols and TCP procotols in RS485 buses as described in claim 1, feature It is：Device numbering of the system configuration file comprising the communication slave station equipment in RS485 buses, device address, agreement The IP address of the data remote host of type and Ethernet interface；The communication slave station equipment information table is matched according to system File generated is set, it is a pair of to communicate the communication slave station equipment one connected in information and RS485 buses in slave station equipment information table It answers.

5. the conversion method between multi-protocols and TCP procotols in RS485 buses as described in claim 1, feature It is：Allow the data for transmitting various protocols in the same RS485 buses：DL/T645-1997, CJ/T188-2004 and GB/ T19582-2008 communication protocols.

6. the conversion method between multi-protocols and TCP procotols in RS485 buses as described in claim 1, feature It is：The communication slave station equipment information table, by the table, communication main station equipment can carry out each communication slave station equipment unification Management；Communication main station equipment can determine whether out the device numbering of transmission protocol data according to the address of protocol data, then pass through access Slave station equipment information table is communicated, protocol type used in protocol data is can get.