A distributed control system without a master controller based on Ethernet communication

Abstract

The present invention discloses a distributed control system without a master controller based on Ethernet communication, comprising sub-devices and intelligent distributed controllers, wherein the sub-devices are electrically connected to the intelligent distributed controllers, and Ethernet communication is adopted between the intelligent distributed controllers; the present invention discloses a distributed control system without a master controller based on Ethernet communication, because there is no master controller in the system, and each distributed controller has an independent logic control function; even if the controller of a certain sub-device fails, a large number of other devices in the system can still continue to operate normally, thereby improving the reliability of continuous operation of the system; all distributed controllers are connected by Ethernet, and system deployment and structural expansion can be easily completed; operators only need to reset the scale of the system, and do not need to modify the original software engineering, and the overall investment cost of the system can also be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic product production, and in particular relates to a distributed control system without a main controller based on Ethernet communication. Background Art

[0002] In the field of plastic pellet raw material processing, the drying system is the most important and complex equipment system. Raw material drying involves the joint use of multiple equipment, such as drying air generating equipment, raw material drying barrels and conveying equipment. Each equipment involved in the drying process contains multiple sensors and control components, which requires a control system to coordinate the control of multiple equipment to ensure the drying effect of all materials in the drying system. The control part of the system usually adopts two forms: centralized control or distributed control.

[0003] Centralized control consists of a master controller and input and output expansion modules. All input and output signals are centrally connected to the control system through transmission media such as cables. This is also the most common and traditional system integration method.

[0004] All components of the control system are in the same electric control cabinet. The input signals of all sensors on site and the output signals to the control actuators need to be connected to the control system, and a large number of cables and other signal connection media need to be laid;

[0005] If the system needs to be expanded, additional input and output modules must be added to the control system, and additional cables must be laid on site. Each system change requires customization;

[0006] Distributed control consists of a master controller and remote control nodes. The master controller and all remote control nodes are connected by communication. Input and output signals no longer need to be centrally connected to one place, but can be connected to the nearest remote control node according to the system structure. The master controller indirectly collects input signals and controls output signals through remote control nodes. Now more and more equipment manufacturers in the industry use this system integration method;

[0007] When the system needs to add a remote control node, the communication bus needs to be connected to the previous node. The deployment location of the node and the laying path of the communication bus need to be considered on site, which increases the difficulty of expansion.

[0008] If the communication medium between two nodes is interrupted, all remote control nodes after the interruption will lose contact with the main controller, and the devices managed by these nodes will be out of control, thus affecting the overall operation of the system.

[0009] It should be noted that the above contents belong to the technical knowledge of the inventor and do not necessarily constitute prior art. Summary of the invention

[0010] In order to solve the above problems, the purpose of the present invention is to provide a distributed control system without a master controller based on Ethernet communication, which solves the scalability and continuous operation stability of a plastic particle drying system.

[0011] To achieve the above objectives, the present invention proposes a distributed control system without a master controller based on Ethernet communication, characterized in that it includes sub-devices and intelligent distributed controllers, the sub-devices are electrically connected to the intelligent distributed controllers, and Ethernet communication is adopted between the intelligent distributed controllers.

[0012] In one example, the intelligent distributed controller is provided with an Ethernet interface.

[0013] In one example, each of the intelligent distributed controllers is installed with a logic control program, and each of the intelligent distributed controllers transmits control signals via Ethernet.

[0014] In one example, the intelligent distributed controller defines its own functional identity and its sequence number in the system based on its own IP address. If one of the sub-devices fails and cannot establish communication with other intelligent distributed controllers, the other intelligent distributed controllers can skip communicating with the failed intelligent distributed controller, and the system can maintain continuous operation.

[0015] In one example, the communication data between the intelligent distributed controllers includes common data and sub-device data. The common data includes the number of system sub-devices, dew point control setting values, operating time setting values, etc., which are set when the system is deployed and can also be modified secondary; the sub-device data is updated by each logic controller to update the corresponding data segment. According to the number of the sub-devices, the communication data includes multiple sub-device data segments.

[0016] In one example, the sub-equipment includes a drying wind generator module, a drying barrel, a conveying fan module, etc. for plastic particle drying related devices.

[0017] The distributed control system without a master controller based on Ethernet communication proposed by the present invention can bring the following beneficial effects:

[0018] 1. Because there is no main controller in the system and each distributed controller has independent logic control functions, the risk of the entire system being paralyzed due to the failure of the main controller can be distributed to each independent device. Even if the controller of a sub-device fails, it will only affect the sub-device, and a large number of other devices in the system can continue to operate normally, thereby improving the reliability of the system's continuous operation.

[0019] 2. All distributed controllers are connected by Ethernet, and with the current network connection technology, system deployment and structural expansion can be easily completed.

[0020] 3. Because the system control programs are scattered in each intelligent distributed controller, when the system needs to be expanded, it is only necessary to connect the new sub-device to the original system through the network; the operator only needs to reset the scale of the system without modifying the original software engineering; system deployment and structural expansion can also be easily completed from the software level.

[0021] 4. With the development of the control system industry, the cost of intelligent distributed controllers and traditional distributed control nodes is not much different; and by eliminating the main controller, the overall investment cost of the system can also be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0024] Figure 2 It is a schematic diagram of the communication structure of the intelligent distributed controller of the present invention;

[0025] Figure 3 It is a structural schematic diagram of a communication sub-device failure of an intelligent distributed controller of the present invention;

[0026] Figure 4 It is a schematic diagram of the communication data structure of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of traditional centralized control;

[0028] Figure 6 This is a schematic diagram of the structure of traditional distributed control. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in an exemplary manner in conjunction with the accompanying drawings.

[0030] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, the first feature "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one scheme", "some schemes", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the scheme or example are included in at least one scheme or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same scheme or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more schemes or examples in a suitable manner.

[0034] like Figure 1 to Figure 4As shown, an embodiment of the present invention proposes a distributed control system without a master controller based on Ethernet communication, which includes a sub-device 1 and an intelligent distributed controller 2. The sub-device 1 is electrically connected to the intelligent distributed controller 2. The intelligent distributed controllers 2 use Ethernet communication. The intelligent distributed controllers 2 are provided with Ethernet interfaces. The intelligent distributed controllers 2 are all installed with logic control programs. Each intelligent distributed controller 2 transmits control signals through Ethernet. The intelligent distributed controller 2 defines its own functional identity and the sequence number in the system according to its own IP address. If a sub-device 1 fails and cannot establish communication with other intelligent distributed controllers 2, the other intelligent distributed controllers 2 can skip communicating with the failed intelligent distributed controller 2, and the system can maintain continuous operation. The communication data between the intelligent distributed controllers 2 includes public data and sub-device data. The public data includes the number of system sub-devices, dew point control setting values, operating time setting values, etc., which are set when the system is deployed and can also be modified twice; the sub-device 1 data is updated by each logic controller to the corresponding data segment. According to the number of sub-devices 1, the communication data contains multiple sub-device 1 data segments. The sub-device 1 includes a drying wind generator module, a drying barrel, a conveying fan module, etc. for plastic particle drying related devices.

[0035] Working principle: Each intelligent distributed controller receives communication data from the previous intelligent distributed controller, understands the operation status and operation requirements of the entire system based on public data and sub-device data of other intelligent distributed controllers, adjusts the operation of the device in real time, and then updates the real-time data of the device to the corresponding sub-device data segment according to the operation status of the device, and then sends the data to the next intelligent distributed controller; when a sub-device fails, its previous intelligent distributed controller will lose the communication connection with it. When the current intelligent distributed controller finds that there is no response to the communication with the next intelligent distributed controller, it can directly skip the next intelligent distributed controller according to its own serial number and the definition of the number of system sub-devices, and establish a communication connection with the next intelligent distributed controller.

[0036] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0037] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A distributed control system without a master controller based on Ethernet communication, characterized in that: It includes a sub-device and an intelligent distributed controller, the sub-device is electrically connected to the intelligent distributed controller, the intelligent distributed controllers communicate with each other using Ethernet, the intelligent distributed controllers are all installed with a logic control program, and each of the intelligent distributed controllers transmits control signals via Ethernet. Each of the intelligent distributed controllers receives communication data from the previous intelligent distributed controller, understands the operation status and operation requirements of the entire system based on the public data and the sub-device data of other intelligent distributed controllers, updates the real-time data to the corresponding sub-device data segment according to the operation status of the device, and then sends the data to the next intelligent distributed controller; The intelligent distributed controller defines its own functional identity and the sequence number in the system according to its own IP address. If a certain sub-device fails and cannot establish communication with other intelligent distributed controllers, the faulty intelligent distributed controller is skipped and a communication connection is directly established with the next intelligent distributed controller to maintain the continuous operation of the system. When a certain sub-device fails, its previous intelligent distributed controller loses the communication connection with it. When the previous intelligent distributed controller finds that there is no response to the communication with the next intelligent distributed controller, it can directly skip the next intelligent distributed controller according to its own sequence number and the definition of the number of sub-devices in the system, and establish a communication connection with the next intelligent distributed controller; The sub-devices include a dry air generator module, a drying barrel, and a conveying fan module. The communication data between the intelligent distributed controllers include common data and sub-device data. The common data includes the number of system sub-devices, dew point control setting values, and operating time setting values. The settings are completed when the system is deployed and can also be modified secondary; the sub-device data is updated by each logic controller to update the corresponding data segment. According to the number of the sub-devices, the communication data contains multiple sub-device data segments.

2. A distributed control system without a master controller based on Ethernet communication according to claim 1, characterized in that: The intelligent distributed controller is provided with an Ethernet interface.

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