A DCS dual-channel non-switching duplex modbus communication system and method

Abstract

The present invention belongs to the technical field of distributed control system DCS, and specifically relates to a DCS dual-channel non-switching duplex modbus communication system and method, including a DCS system and a third-party system communication structure, and the system hardware equipment includes two DCS platform non-redundant communication cards, two PLC platform Ethernet / IP communication cards, two Ethernet switches and PLC side master-slave racks; the present invention avoids accidents caused by complete communication interruption due to DCS side communication card failure, drive loss, switch failure and communication medium damage, and ensures the safe and stable operation of the factory production line. At the same time, due to the high reliability and strong fault tolerance of this communication method, the factory has promoted the dual-channel non-switching duplex communication method to the communication between other third-party systems and DCS, which greatly improves economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of distributed control systems (DCS), and in particular relates to a DCS dual-path non-switching same-duplex Modbus communication system and method. Background Art

[0002] At present, DCS systems in the industrial control field and third-party control systems mainly communicate in real time through communication cards that support the Modbus protocol, including non-redundant single-channel communication and redundant dual-channel communication.

[0003] The non-redundant single-channel communication mode uses a DCS non-redundant communication card to communicate with the third-party system communication card in a single link in real time. There is a common risk of complete interruption of communication due to card failure, drive loss, and communication medium damage.

[0004] The redundant communication method uses DCS redundant communication cards to achieve redundant communication with third-party systems. This type of redundant communication is not truly real-time redundant communication. It will only switch to the backup communication card when the main redundant communication fails, and there is a possibility of switching failure. At the same time, there have been many cases in the industrial control field where the overall drive of the redundant communication card was lost, resulting in a complete interruption of both communications at the same time, causing great economic and property losses. Summary of the invention

[0005] The purpose of the present invention is to address the above-mentioned drawbacks and propose a DCS dual-channel non-switching duplex Modbus communication system and method, which realizes the simultaneous reception and transmission of data through dual channels, and can effectively ensure the effectiveness of communication establishment and data transmission when a single or even multiple faults occur in the communication link.

[0006] The technical solution of the present invention is as follows:

[0007] A DCS dual-channel non-switching duplex modbus communication system, a DCS system and a third-party system communication structure, the system hardware equipment includes two DCS platform non-redundant communication cards, two PLC platform Ethernet / IP communication cards, two Ethernet switches and PLC side platform master and slave racks;

[0008] Use TCP / IP network communication protocol to connect the non-redundant communication card on the DCS side and the third-party system communication card on the same channel to the same Ethernet switch through network cables, and configure another communication channel redundantly to achieve two-channel one-to-one real-time communication in hardware;

[0009] A redundant PLC controller and a corresponding redundant conversion module are set up on the third-party system PLC controller side to ensure that the backup controller can be switched when the main PLC controller fails;

[0010] The two PLC platforms of the third-party system are connected through an Ethernet switch. At the same time, the two Ethernet switches are connected through a network cable for communication and interconnection, so that the master and slave PLC IP addresses can be automatically exchanged when the PLC performs master-slave conversion;

[0011] The two non-redundant communication cards of the DCS are set with the same destination IP address - the address of the main PLC communication card of the third-party system. Through the Ethernet switch, the main PLC communication card can simultaneously receive and send communication data from the two controllers on the DCS side.

[0012] A PLC communication card is connected one-to-one with a DCS non-redundant communication card, forming a two-way one-to-one communication mode, and then setting up two duplex data transmission channels, and the two channels receive and send data simultaneously.

[0013] The master-slave racks on the third-party system side are designed as a fully redundant structure to ensure that data signals are transmitted in two channels in real time within the third-party system.

[0014] In the third-party system, the redundant module is used to realize automatic exchange of IP addresses when the PLC controller switches from master to slave, and then the same destination IP address is configured for the DCS communication card.

[0015] The non-redundant communication card on the DCS side only sets a unique target IP address.

[0016] A DCS dual-channel non-switching duplex modbus communication system method, which writes driver configuration file codes for two DCS non-redundant communication cards respectively, configures independent and different IP addresses, and performs independent driver installation;

[0017] The corresponding redundant data type, that is, the same module has dual-channel input or output at the same time, realizing real-time duplex input / output of dual-channel data;

[0018] Taking the IP address of the third-party system as the target, according to the corresponding number of bits of the subnet mask, the network identifier of the communication segment of the third-party system-DCS is calculated, and then the communication IP addresses of the two non-redundant communication cards on the DCS side are designed, and finally the timely and accurate driver configuration file is compiled;

[0019] Use the corresponding redundant data types INR / BINR / BOUTR and open the validity of the redundant data module's dual-channel data reception / transmission to achieve real-time duplex input / output of dual-channel data; for real integer / digital output data types, also use redundant data modules to achieve dual-channel data output.

[0020] The two non-redundant communication cards are configured with independent drivers to ensure that when the communication driver of one of the non-redundant cards is lost, the other communication card can remain unaffected and maintain normal working status; at the same time, the redundant data type is used to replace the traditional repetitive data redundancy method, that is, one data module replaces two data modules, reducing the data communication volume between the two systems by 50%, thereby indirectly improving communication reliability.

[0021] The beneficial effects of the present invention are:

[0022] By using the technical solution of the present invention, accidents caused by complete interruption of communication due to communication card failure, driver loss, switch failure and communication medium damage on the DCS side are avoided, ensuring the safe and stable operation of the factory production line. At the same time, due to the high reliability and strong fault tolerance of this communication method, the factory has promoted the dual-channel non-switching duplex communication method to the communication between other third-party systems and DCS, which greatly improves economic benefits.

[0023] This invention innovatively proposes a special redundant working mode for industrial communication systems, which greatly improves the reliability of communications from third-party systems to DCS. It has great economic value and is significantly helpful in improving the level of safe and stable operation of large factories. The design and implementation of the communication mode also provides a good reference blueprint for improving the reliability of industrial Ethernet communication technology systems in the subsequent industrial control field. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the communication structure between the DCS system of the present invention and the third-party system;

[0025] Figure 2 It is a schematic diagram of the master-slave IP exchange of the PLC communication card of the present invention;

[0026] Figure 3 It is a schematic diagram of implementing the IIN / BIN / IOUT / BOUT redundant communication of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] like Figure 1 As shown, a DCS dual-channel non-switching duplex modbus communication system, a DCS system and a third-party system communication structure, the system hardware equipment includes two DCS platform non-redundant communication cards, two PLC platform Ethernet / IP communication cards, two Ethernet switches and PLC side master and slave racks.

[0029] By using the TCP / IP network communication protocol through the network cable, the non-redundant communication card on the DCS side and the communication card on the same channel of the third-party system are connected to the same Ethernet switch, and another communication channel is redundantly configured to realize two-way one-to-one real-time communication in hardware; a redundant PLC controller and a corresponding redundant conversion module are set on the PLC controller side of the third-party system to ensure that when the main PLC controller fails, it can switch to the backup controller; the two PLC platform Ethernet / IP communication cards of the third-party system are connected through the Ethernet switch, and the two Ethernet switches are connected through the network cable for communication interconnection, so that the master and slave PLC IP addresses can be automatically exchanged when the PLC performs master-slave conversion; the two non-redundant communication cards of the DCS set the same destination IP address - the address of the main PLC communication card of the third-party system, and the main PLC communication card is enabled to simultaneously receive and send communication data from the two controllers on the DCS side through the Ethernet switch.

[0030] A PLC communication card is connected one-to-one with a DCS non-redundant communication card, forming a two-way one-to-one communication mode, and then setting up two duplex data transmission channels, and the two channels receive and send data at the same time;

[0031] The master-slave racks on the third-party system side are designed as a fully redundant structure to ensure that data signals have two channels of data transmission in real time within the third-party system. When one channel fails, data transmission is not affected.

[0032] In the third-party system, the redundancy module is used to realize automatic exchange of IP addresses when the PLC controller switches from master to slave. Then, by configuring the same destination IP address for the DCS communication card, two communication cards can access the communication card of the main PLC at the same time.

[0033] When communicating with the redundant communication card of the third-party system, the non-redundant communication card on the DCS side only sets a unique target IP address, that is, the main PLC. There is no need to pay attention to the IP address of the standby PLC, abandoning the traditional design concept of setting two different target IP addresses for the main and standby communication cards.

[0034] The dual-channel one-to-one structure eliminates the risk of failure in the traditional redundant communication master-slave switch, and will not lose data due to the master-slave switch. At the same time, it eliminates the hidden danger of complete communication interruption due to single failure phenomena such as damage to the communication card and damage to the communication medium. Because the third-party system side is configured with the same IP address, communication confusion is not prone to occur. At the same time, it realizes the design concept that when one of the communication cards on the DCS side fails, there are still two channels of data communication in real time in the third-party system, which improves communication reliability.

[0035] A DCS dual-channel non-switching duplex modbus communication method

[0036] Write driver configuration file codes for the two DCS non-redundant communication cards respectively, configure independent IP addresses, and install independent drivers, so that the communication drivers of the two communication cards are completely independent, do not affect each other, and work at the same time;

[0037] The corresponding redundant data type, that is, the same module has dual-channel input or output at the same time, realizes the real-time duplex input / output of dual-channel data, realizes the redundant selection of data through software, and completes the communication implementation for real integer / digital data type.

[0038] The two non-redundant communication cards are configured with independent drivers to ensure that when the communication driver of one of the non-redundant cards is lost, the other communication card can remain unaffected and maintain normal working status; at the same time, the redundant data type is used to replace the traditional repetitive data redundancy method, that is, one data module replaces two data modules, reducing the data communication volume between the two systems by 50%, thereby indirectly improving communication reliability.

[0039] Taking the IP address of the third-party system as the target, the network identifier of the communication segment of the third-party system-DCS is calculated according to the corresponding number of bits of the subnet mask, and then the communication IP addresses of the two non-redundant communication cards on the DCS side are designed. Finally, the timely and accurate driver configuration file is written, and the communication mode of transmitting the same data simultaneously through two signal transmission channels is realized from the software perspective;

[0040] Use the corresponding redundant data types INR / BINR / BOUTR and open the validity of the redundant data module's dual-channel data reception / transmission to achieve real-time duplex input / output of dual-channel data; for real integer / digital output (IOUT / BOUT) data types, use redundant data modules to achieve dual-channel data output, and realize communication for real integer / digital input (IIN / BIN) data types.

Claims

1. A DCS dual-channel non-switching duplex modbus communication system, characterized by: Including the communication structure between the DCS system and the third-party system. The system hardware equipment includes two DCS platform non-redundant communication cards, two PLC platform Ethernet / IP communication cards, two Ethernet switches and PLC side platform master and slave racks; Use TCP / IP network communication protocol to connect the non-redundant communication card on the DCS side and the third-party system communication card on the same channel to the same Ethernet switch through network cables, and configure another communication channel redundantly to achieve two-channel one-to-one real-time communication in hardware; A redundant PLC controller and a corresponding redundant conversion module are set up on the third-party system PLC controller side to ensure that the backup controller can be switched when the main PLC controller fails; The two PLC platforms of the third-party system are connected through an Ethernet switch. At the same time, the two Ethernet switches are connected through a network cable for communication and interconnection, so that the master and slave PLC IP addresses can be automatically exchanged when the PLC performs master-slave conversion; The two non-redundant communication cards of the DCS are set with the same destination IP address - the address of the main PLC communication card of the third-party system. Through the Ethernet switch, the main PLC communication card can simultaneously receive and send communication data from the two controllers on the DCS side.

2. A DCS two-way non-switching duplex modbus communication system as claimed in claim 1, characterized in that: A PLC communication card is connected one-to-one with a DCS non-redundant communication card, forming a two-way one-to-one communication mode, and then setting up two duplex data transmission channels, and the two channels receive and send data simultaneously.

3. A DCS two-way non-switching duplex modbus communication system as claimed in claim 1, characterized in that: The master-slave racks on the third-party system side are designed as a fully redundant structure to ensure that data signals are transmitted in two channels in real time within the third-party system.

4. A DCS two-way non-switching duplex modbus communication system as claimed in claim 1, characterized in that: In the third-party system, the redundant module is used to realize automatic exchange of IP addresses when the PLC controller switches from master to slave, and then the same destination IP address is configured for the DCS communication card.

5. A DCS two-way non-switching duplex modbus communication system as claimed in claim 1, characterized in that: The non-redundant communication card on the DCS side only sets a unique target IP address.

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