Deterministic protocol conversion method for multi-protocol industrial equipment

Abstract

The invention discloses a deterministic protocol conversion method for multi-protocol industrial equipment, and relates to the technical field of Internet of Things, and the method comprises the following steps: S1, initializing hardware; s2, the multi-protocol industrial equipment is sequentially connected to a protocol access module through different physical connectors; s3, transmitting a conversion operation to a protocol conversion configuration module; s4, according to the conversion parameters and the conversion rules in the conversion operation, in combination with constraint conditions in a deterministic protocol conversion algorithm, solving the optimization target by using a Satisfiability Model Theory solver to obtain a scheduling scheme; and S5, according to the scheduling scheme, the protocol conversion scheduler carries the data of the shared memory block according to the conversion operation, and sends the data to the corresponding protocol access module to execute protocol conversion. According to the invention, the interoperability of equipment is improved, the flexibility and expansibility of the conversion system are improved, the cost and time of system implementation and maintenance are reduced, and the stability and predictability of the system can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of Internet of Things, and in particular to a deterministic protocol conversion method for multi-protocol and multi-industrial protocol equipment. Background Art

[0002] In the Industrial Internet of Things (IIoT), devices usually come from different suppliers and use multiple communication protocols, such as industrial wired network protocols including CAN, EtherCAT, PROFINET, etc. and industrial wireless network international standards including LoRa, ZigBee and WIA-PA. These protocols have their own characteristics and cannot communicate directly with each other, resulting in limited interoperability between devices. Traditional protocol conversion methods usually rely on middleware or gateway devices to achieve basic protocol access and conversion, but often face problems such as low transmission efficiency and difficulty in meeting real-time and deterministic requirements. Especially in industrial automation and control systems, these situations may cause serious system failures or performance degradation.

[0003] With the widespread application of IIoT, in order to cope with the industrial field environment composed of multiple network protocols and meet the strict requirements of the industrial field for deterministic communication, a protocol conversion solution that can ensure low latency and high reliability in complex networks is urgently needed. This solution not only needs to efficiently process data conversion between protocols, but also must be able to complete data transmission within a strict time window to avoid system failures caused by delays or errors. Therefore, designing an efficient and reliable deterministic protocol conversion method to achieve deterministic communication between devices with different protocols has become one of the keys to support the development of IIoT.

[0004] After searching the existing literature, it was found that the Chinese patent application number is 202210050225.2, and its name is a method and device for deterministic conversion of industrial heterogeneous network protocols. It discloses: after receiving the information flow at the input port, they are timestamped and assigned corresponding control words. Subsequently, priorities are assigned within the device according to the quality of service of the information flow, and a gating list is designed according to the constraints to control the output of information flows of different priorities, and finally the output information flow is converted into the corresponding protocol and transmitted to the target network. Although this patent has designed the determinism of protocol conversion, it requires the design of a protocol stack for each protocol, which is highly complex and has low transmission efficiency.

[0005] Other patents related to protocol conversion: Chinese patent application number is 201410019937, entitled: Multi-protocol conversion device based on wireless ZigBee, CAN bus and MODBUS / TCP and its implementation method, which discloses: the microprocessor serves as the control center of the device, and completes the data conversion between the three protocols of wireless ZigBee network, CAN bus and MODBUS / TCP Ethernet by opening an address conversion mapping table, thereby realizing a wireless / wired heterogeneous control network and completing the parsing and distribution of information between different protocols; Chinese patent application number is 200810201577, entitled: A conversion method between multi-protocol buses, which discloses: the microprocessor receives DeviceNet, Profibus and Modbus / TCP protocol data and saves them in the microprocessor, and performs protocol conversion according to the data periodicity.

[0006] The Chinese patent application number is 200810201578.8, and its name is: Multi-protocol gateway for industrial wireless network access to industrial Ethernet and field bus and protocol conversion method, which discloses: protocol conversion between industrial wireless network access to MODBUS / TCP industrial Ethernet and PROFIBUS-DP field bus based on IEEE802.15.4a is realized by microprocessor control; the Chinese patent application number is 201610201994, and its name is: Industrial control automation network communication protocol converter and communication protocol conversion method, and its specific approach is: using a microprocessor to realize protocol conversion between free protocol and Modbus RTU protocol and TCP / IP protocol. However, the above patents all perform protocol conversion on three fixed wired / wireless protocols, have poor scalability, and do not have a flexible online configuration method; the Chinese patent application number is 202110535853, and its name is Industrial Heterogeneous Network High-Speed ​​Protocol Conversion Device and Parallel Processing Unit. Its specific approach is: use wireless modules and network cards to respectively send and receive industrial wireless network data, industrial wired network data, and IPv6 backbone network data, and after entering the protocol conversion unit, perform parallel processing and conversion on the data, and the protocol conversion device can be managed and controlled through the SDN management interface unit.

[0007] The above patents realize the access and high-speed conversion of multiple industrial wireless / wired protocols, but do not guarantee the determinism of the protocol conversion process. In summary, it is necessary to design a deterministic protocol conversion method with strong versatility, scalability and flexibility.

[0008] Therefore, those skilled in the art are committed to developing a deterministic protocol conversion method for multi-industrial protocol devices. Summary of the invention

[0009] In view of the above-mentioned defects of the prior art, the technical problems to be solved by the present invention are: the industrial protocol conversion process is uncertain; the protocol conversion process is not modeled, and most of them are fixed conversions after one-to-one or many-to-one access, which lacks flexibility and scalability.

[0010] To achieve the above object, the present invention provides a deterministic protocol conversion method for multi-industrial protocol equipment, characterized in that the method comprises the following steps:

[0011] Step S1: Initialize the hardware including the driver, shared memory block, protocol access module, protocol conversion configuration module, and protocol conversion scheduler, and adjust the required modules to a ready state;

[0012] The protocol access module is used to connect devices of various industrial protocols, and store the received data of multi-protocol devices in the shared memory block;

[0013] The protocol conversion configuration module is used to configure and maintain conversion parameters and conversion rules of various protocol devices;

[0014] The protocol conversion scheduler schedules the data in the shared memory block according to a conversion operation including conversion parameters and conversion rules, and communicates with the multi-protocol device through the protocol access module;

[0015] Step S2: Different protocol devices are sequentially connected to the protocol access module through different physical connectors;

[0016] Step S3: the conversion operation is sent to the protocol conversion configuration module;

[0017] Step S4: according to the conversion parameters and conversion rules in the conversion operation, combined with the constraints in the deterministic protocol conversion algorithm, the Satisfiability Model Theory solver is used to solve the optimization target to obtain a scheduling solution;

[0018] Step S5: According to the scheduling scheme, the protocol conversion scheduler moves the data of the shared memory block according to the conversion operation and sends it to the corresponding protocol access module to perform protocol conversion;

[0019] Furthermore, the various industrial protocol devices in step S2 are connected to the protocol access module through their respective physical connectors and then transferred to the shared memory block using a bus;

[0020] Further, the protocol conversion configuration module in step S3 can be configured via SPI or TCP / IP communication protocol;

[0021] Furthermore, the set of the conversion operations in step S3 is {ψ1, ψ2, …, ψ n} means that there are n∈N * The conversion operation is described by a tuple, namely: The formulas represent the read sub-operation frame, the write sub-operation frame, the conversion data amount, the conversion operation cycle, the conversion operation deadline and the allowed conversion jitter in sequence;

[0022] Furthermore, the constraint conditions of step S4 include non-conflict constraint, sequence constraint, delay constraint and jitter constraint;

[0023] Non-conflicting constraints are defined as:

[0024]

[0025] in, Indicates the start time of data frame transmission, op and γ indicate the options of sub-operation, which can be r or w, that is, read sub-operation or write sub-operation.

[0026] Order constraint definition:

[0027]

[0028] Latency constraints:

[0029] T n ≤D n ,(3)

[0030]

[0031] Where k represents a conversion cycle, that is, the value starts at the beginning of (k-1) and ends when the data frame transmission is completed. n,k,w Indicates the time consumption of writing sub-operation, t n,k,r and t n,k,w Related to transmission delay, expressed as follows:

[0032]

[0033] Where c is the link speed, l r , l w , l n Indicates the data size of the read command, read header, write header, write response, and conversion data.

[0034] Jitter constraint definition:

[0035]

[0036] in, is the conversion jitter.

[0037] Furthermore, the scheduling solution formula of step S4 is:

[0038] Further, the Satisfiability Model Theory solver of step S4 is a Z3 solver; further, the scheduling scheme is a table containing the start time of each data frame, that is,

[0039] Further, each data frame performs the conversion operation sequentially according to time;

[0040] Furthermore, each data frame is transmitted in its own time slot.

[0041] The universal protocol conversion model proposed in the present invention is applicable to the data streams of various connected industrial protocol devices. This universality improves the interoperability of the devices, enhances the flexibility and scalability of the conversion system, reduces the complexity of integrating new devices, and reduces the cost and time of system implementation and maintenance. On this basis, a deterministic protocol conversion mechanism is also proposed. By solving the scheduling scheme, it ensures that each conversion operation is completed within the scheduled time. This feature is particularly critical for the real-time requirements in industrial environments, especially in scenarios with high reliability, low latency and high efficiency requirements. It can effectively improve the stability and predictability of the system, meet the performance requirements in large-scale industrial applications, and provide technical support for the future development of industrial intelligence. It has broad market demand and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a process framework of a deterministic protocol conversion method for multi-industrial protocol equipment according to the present invention;

[0043] Figure 2 A deterministic protocol conversion framework diagram of an embodiment of the present invention;

[0044] Figure 3 is a flow chart of deterministic protocol conversion according to an embodiment of the present invention;

[0045] Figure 4 Schematic diagram of a conversion scheduling scheme according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0047] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0048] The present invention aims to improve the problems of insufficient flexibility and determinism of existing industrial protocol conversion methods, and provides a deterministic protocol conversion method for multi-industrial protocol equipment.

[0049] like Figure 1-4 As shown in , the method is located in the protocol conversion scheduler, wherein the protocol access module is used to connect devices of various industrial protocols, such as EtherCAT, Profinet, ZigBee, LoRa, etc., and corresponds to various protocol devices one by one;

[0050] The shared memory block is used to store data of various protocol devices, which are stored in the form of input / output data blocks;

[0051] The protocol access module receives data from various protocol devices and stores it in a shared memory block;

[0052] The protocol conversion configuration module is used to configure and maintain the conversion parameters and conversion rules of various protocol devices;

[0053] The protocol conversion scheduler schedules the input / output data in the shared memory block according to the conversion parameters and conversion rules, and communicates with the multi-protocol devices through the protocol access module to ensure the real-time and deterministic nature of the conversion operation.

[0054] The following uses the conversion between multiple protocols as an example to illustrate the deterministic protocol conversion method, wherein the conversion parameters and conversion rules included in the conversion operation are shown in Table 1:

[0055] Table 1 Conversion operation table

[0056]

[0057] like Figure 3 As shown, the method comprises the following steps:

[0058] Step S1: Initialize first, including related hardware such as driver, memory, protocol access module, protocol conversion configuration module and protocol conversion scheduler. Adjust all modules to be used to the ready state.

[0059] Preferably, the RS485 bus can be used to connect the protocol access module and set the correct baud rate, here taking 0.5Mbps as an example.

[0060] Furthermore, the protocol conversion configuration module can be configured through communication protocols such as SPI, TCP / IP, etc.

[0061] Step S2: Wait for the multi-protocol devices to connect to the protocol access module in turn. If the connection is completed, enter step S3; otherwise, wait for all protocol devices to connect successfully. During the waiting process, if a timeout occurs, the judgment will jump out, the error information will be reported and the program will end.

[0062] Furthermore, different protocol devices are connected to each other through different physical connectors and protocol access modules and then transferred to the shared memory block through a bus.

[0063] Step S3: Wait for the conversion operation to be sent to the protocol conversion configuration module. If the data of the conversion operation is successfully received, the data will be sent to the protocol conversion scheduler for scheduling, and then enter S4; otherwise, it will continue to wait for the correct data to arrive.

[0064] For the protocol conversion process, {ψ1,ψ2,…,ψ n} represents a set of transformation operations, with a total of n∈N * Conversion operation. Consider each conversion operation as a cyclic process, which consists of two sub-operations: read sub-operation and write sub-operation, which represent reading source protocol data and writing target protocol data respectively.

[0065] Use a tuple to describe it, namely: It represents the read sub-operation frame, the write sub-operation frame, the conversion data amount, the conversion operation cycle, the conversion operation deadline and the allowed conversion jitter in sequence.

[0066] Assume that in the industrial field there is ν∈N * Multi-protocol industrial equipment access, in the above tuple, represents the process of conversion operation n reading source protocol device src∈ν ​​for the kth time, and r represents the read sub-operation. Similarly, represents the process of writing the conversion operation n to the target protocol device, dst∈ν, for the kth time, and w represents the writing sub-operation. Here, a protocol device can be either a source protocol device or a target protocol device. k∈N * Indicates the order of conversion operations. The conversion operation cycle is represented by Tn, which is set by the user or actual scenario requirements, and the conversion operation deadline is represented by Dn. Generally speaking, the values ​​of Tn and Dn are equal.

[0067] The conversion operation takes Table 1 as an example, srcPro represents the source protocol name, dstPro represents the target protocol name. If there are multiple devices with the same protocol, the protocol names need to be distinguished; srcAdd represents the source protocol address, dstAdd represents the target protocol address, and they represent the starting address of the data to be converted; byteSize represents the length of the data to be converted; convPeriod represents the conversion period, in ms; convDdl represents the conversion deadline, in ms; convJitter represents the tolerable conversion jitter, in μs.

[0068] Step S4: The protocol conversion scheduler schedules the conversion operation. Based on the conversion parameters and conversion rules in the conversion operation, combined with the constraints in the deterministic protocol conversion algorithm, the Satisfiability Model Theory (SMT) solver is used to solve the optimization target to obtain a scheduling solution. If a scheduling solution is obtained, enter S5; otherwise return to S3.

[0069] Furthermore, the connected industrial protocol data is scheduled on a TDMA-based transmission line, constraints are established according to set parameters, and an optimization problem is solved in a protocol conversion scheduler to obtain a scheduling solution.

[0070] The constraints in the deterministic protocol conversion method include conflict-free constraints, order constraints, delay constraints and jitter constraints.

[0071] 1) Collision-free constraint: ensures that only one data frame is transmitted through the physical cable based on TDMA at a time.

[0072]

[0073] in, Indicates the start time of data frame transmission, op and γ indicate the options of sub-operation, which can be r or w, that is, read sub-operation or write sub-operation.

[0074] 2) Order constraint: defines that the conversion operation must obtain the source protocol data before converting it to the target protocol data.

[0075] Therefore, the following conversion sequence constraints are constructed so that during conversion, the read sub-operation is completed before the write sub-operation.

[0076]

[0077] 3) Delay constraint: It stipulates that the conversion time between protocols, that is, the time from the start of conversion to the output of target protocol data must be less than the conversion deadline in the conversion rule.

[0078] T n ≤D n, (3)

[0079]

[0080] Where k represents a conversion cycle, that is, the value starts at the beginning of (k-1) and ends when the data frame transmission is completed. n,k,w Indicates the time consumption of writing sub-operation, t n,k,r and t n,k,w Related to transmission delay, expressed as follows:

[0081] The computational delay and propagation delay here are very small and can be ignored.

[0082]

[0083] Where c is the link speed, l r , l w , l n Indicates the data size of the read command, read header, write header, write response, and conversion data.

[0084] 4) Jitter Constraints: Define the transition jitter (8) and construct the transition jitter constraints in (9) to ensure Must be in J n within the range.

[0085]

[0086] in, is the conversion jitter.

[0087] Finally, the optimization goal (10) is established, which aims to provide guaranteed jitter for all conversion operations and solve the scheduling scheme of the conversion operations.

[0088]

[0089] Preferably, the SMT solver may be a Z3 solver or other solvers.

[0090] Step S5: Start protocol conversion. According to the scheduling plan and the conversion rules in the conversion operation, the data of the shared memory block is moved and sent to the corresponding protocol access module through the bus, for example, RS485, so as to form conflict-free data transmission and ensure the certainty of protocol conversion. During the protocol conversion, if a new conversion operation arrives, the protocol conversion process is reconfigured and returns to S3; otherwise, the current protocol conversion continues.

[0091] Furthermore, the scheduling scheme is a table containing the start time of each data frame, i.e. Each data frame will be transformed sequentially according to time.

[0092] like Figure 4 As shown, a schematic diagram of the protocol conversion scheduling scheme of a specific embodiment of the present invention is shown, in which the horizontal axis represents time. In this schematic diagram, time slots are used as units, the upper right diagonal line represents a read sub-operation, and the lower right diagonal line represents a write sub-operation. It can be observed that each data frame is transmitted in its own time slot, which avoids conflicts and ensures the determinism of the conversion operation.

[0093] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A deterministic protocol conversion method for multi-protocol industrial equipment, characterized in that: The above method comprises the following steps: Step S1: Initialize hardware; Step S2: the multi-protocol industrial device is sequentially connected to the protocol access module through different physical connectors; Step S3: Send the conversion operation to the protocol conversion configuration module; Step S4: according to the conversion parameters and conversion rules in the conversion operation, combined with the constraints in the deterministic protocol conversion algorithm, the Satisfiability Model Theory solver is used to solve the optimization target to obtain a scheduling solution; Step S5: According to the scheduling scheme, the protocol conversion scheduler moves the data of the shared memory block according to the conversion operation and sends it to the corresponding protocol access module to perform protocol conversion; The hardware includes a driver, a shared memory block, a protocol access module, a protocol conversion configuration module, and a protocol conversion scheduler; The protocol access module is used to connect devices of various industrial protocols, and store the received data of multi-protocol industrial devices in the shared memory block; The protocol conversion configuration module is used to receive the conversion operation, configure and maintain the conversion parameters and conversion rules in the conversion operation; The protocol conversion scheduler schedules the data in the shared memory block according to the conversion operation, and communicates with the multi-protocol industrial device through the protocol access module.

2. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 1, characterized in that: The various industrial protocol devices in step S2 are connected to the protocol access module via respective physical connectors and then transferred to the shared memory block via a bus.

3. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 2, characterized in that: The protocol conversion configuration module in step S3 can be configured via SPI or TCP / IP communication protocol.

4. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 1, characterized in that: The set of transformation operations in step S3 is {ψ1, ψ2, …, ψ n } means that there are n∈N * The conversion operation is described by a tuple, namely: It represents the read sub-operation frame, the write sub-operation frame, the conversion data amount, the conversion operation cycle, the conversion operation deadline and the allowed conversion jitter in sequence.

5. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 4, characterized in that: The constraint conditions of step S4 include non-conflict constraint, sequence constraint, delay constraint and jitter constraint; Non-conflicting constraints are defined as: in, and Indicates the start time of data frame transmission, op and γ indicate the options of sub-operation, which can be r or w, that is, read sub-operation or write sub-operation. Order constraint definition: Latency constraints: T n ≤D n , (3) Where k represents a conversion cycle, that is, the value starts at the beginning of (k-1) and ends when the data frame transmission is completed. n,k,w Indicates the time consumption of writing sub-operation, t n,k,r and t n,k,w Related to transmission delay, expressed as follows: Where c is the link speed, l r , l w , l n Indicates the data size of the read command, read header, write header, write response, and conversion data. Jitter constraint definition: in, is the conversion jitter.

6. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 5, characterized in that: The scheduling solution formula of step S4 is: st(1)-(9).

7. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 6, characterized in that: The Satisfiability Model Theory solver in step S4 is a Z3 solver.

8. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 7, characterized in that: The scheduling scheme is a table containing the start time of each data frame, i.e.

9. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 8, characterized in that: The conversion operation is performed sequentially on each data frame according to time.

10. The deterministic protocol conversion method for multi-protocol industrial equipment according to claim 9, characterized in that: Each of the data frames is transmitted in its own time slot.

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