[0012] In order to make the objectives, technical solutions and advantages of the present invention clearer, each embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can appreciate that, in the various embodiments of the present invention, many technical details are set forth in order for the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be realized.
[0013] The first embodiment of the present invention relates to a POWERLINK master, such as figure 1 As shown, the POWERLINK master station refers to a POWERLINK master station based on a real-time operating system, and the above-mentioned real-time operating system is obtained by applying a Xenomai real-time kernel patch to a non-real-time operating system Linux. Among them, the POWERLINK master station based on the real-time operating system with the Xenomai real-time kernel patch includes: a bottom layer module, an event queue module, and a top layer module. The bottom layer module specifically includes a network card driver module and a shared memory module, and the top layer module specifically includes a user module. figure 1 101, 102, 103, and 104 are the real-time driver interfaces of the above modules, respectively. In the process of applying the Xenomai real-time kernel patch to the non-real-time operating system Linux on which the POWERLINK master station is based, the driver interfaces of the above modules are replaced with real-time drivers provided by the RTDM Real Time Driver Module of the Xenomai real-time operating system. interface.
[0014] Specifically, the POWERLINK master station also includes a semaphore, a shared resource, and a switching mechanism between the semaphore and the shared resource in the communication process. The semaphore is used to indicate the number of shared resources, and the parameters of the semaphore can be specified by a flag bit. Indicates that, if the flag bit of the semaphore is set to 1, it means that there is only one semaphore in the POWERLINK master station, and the number of semaphores and shared resources in the POWERLINK master station satisfies a one-to-one correspondence. That is, if the flag bit of the semaphore is set to 3, it means that there are three shared resources available for access in the POWERLINK master station. In the industrial control industry, the flag bit of the semaphore is usually set to 1. Therefore, in the switching mechanism between the semaphore and the shared resource, the POWERLINK master station controls the shared resource according to the semaphore and is only allowed to be accessed by the same thread at the same time. In this way, access to the same shared resource by different threads can be avoided.
[0015] Specifically, the POWERLINK master station starts the Xenomai kernel thread, and the Xenomai kernel thread runs on the kernel layer of the POWERLINK master station based on the real-time operating system. Since the POWERLINK master station is based on the non-real-time operating system Linux, in order to achieve the purpose of real-time communication between the POWERLINK master station and the slave stations, the embodiment of the present invention proposes to add the Xenomai real-time kernel to the non-real-time operating system Linux on which the POWERLINK master station is based. The patch, which includes replacing the kernel threads of the non-real-time operating system Linux on which the POWERLINK master is based, is replaced by the kernel threads of Xenomai, that is, the POWERLINK master runs the kernel threads of Xenomai, which is conducive to improving the relationship between the POWERLINK master and the slave real-time communication between stations.
[0016] Specifically, the POWERLINK master station also includes the user layer and the kernel layer, and the POWERLINK master station runs on the user layer and the kernel layer of the real-time operating system patched with the Xenomai real-time kernel. Among them, the user layer is used to access the information of the protocol stack in the kernel layer, and the information of the protocol stack includes the operation information of the POWERLINK bus, the event queue, and the statistical information of the number of data packets sent and received. Through the user layer, the information of the protocol stack can be easily accessed on the POWERLINK master station kernel, which ensures the real-time nature of information transmission.
[0017] Specifically, the non-real-time operating system on which the POWERLINK master station is based is the Linux operating system. That is, the POWERLINK terminal is based on the Linux operating system. Since the Linux operating system is a non-real-time operating system, the embodiment of the present invention proposes to add the Xenomai real-time kernel patch to the Linux operating system on which the POWERLINK master station is based, so as to make the POWERLINK terminal and the slave station Real-time communication can be achieved between them, reducing the cost of real-time communication.
[0018] Specifically, the POWERLINK master station further includes a data link layer state machine, wherein the data link layer state machine is located on the field programmable gate array FPGA board. The more time-consuming data link layer state machine is implemented on the FPGA (programmable gate array) board, which can further improve the real-time performance and response speed of information transmission.
[0019] For example, first, patch the Linux operating system on which the POWERLINK master station is based with the Xenomai real-time kernel patch; then, modify and replace the Linux API functions used in the source code of the POWERLINK master station with the Xenomai API; finally, modify the source code of the POWERLINK master station. Compile, debug, run. Through the above operations, the POWERLINK master station based on the non-real-time Linux operating system can run under the Linux and Xenomai real-time systems.
[0020] The following is an example of replacing the non-real-time Linux operating system API used in the source code of the POWERLINK master station with the real-time Xenomai API:
[0021] Table 1: Correspondence table between Linux API and Xenomai API
[0022]
[0023]
[0024]
[0025] When the POWERLINK master station is working, the POWERLINK master station system includes two kernel threads, namely the first kernel thread and the second kernel thread. For example, when the POWERLINK master station accesses the slave station, it sends some data packets, and the slave station will feed back the relevant information of these data packets to the master station, and then the first kernel thread in the POWERLINK master station will process the relevant information of these data packets. Parse, and judge whether there is an event to be executed according to the parsed information. If the judgment result is that there is an event to be executed, at this time, the second kernel thread is started to allow it to further process the to-be-processed event.
[0026] After completing the real-time information transmission between the POWERLINK master station and the slave station, it is necessary to close the two kernel threads first, and then exit the POWERLINK master station.
[0027] It is worth mentioning that each module involved in this embodiment is a logical module. In practical applications, a logical unit may be a physical unit, a part of a physical unit, or multiple physical units. A composite implementation of the unit. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in this embodiment.
[0028] In the embodiment of the present invention, the Xenomai real-time kernel patch is applied to the non-real-time operating system Linux, and at the same time, the driver interface of the bottom-level module, the driver interface of the event queue module, and the driver of the top-level user module on the POWERLINK master station based on the non-real-time operating system Linux The interfaces are all replaced with real-time driver interfaces, wherein the real-time driver interfaces are provided by the real-time driver module of the Xenomai real-time operating system. Compared with the prior art, the embodiment of the present invention can realize the real-time communication between the POWERLINK master station and the slave station, and reduce the cost of the real-time communication.
[0029] A second embodiment of the present invention relates to a method for creating a POWERLINK master. like figure 2 shown, including:
[0030] Step 201: Replace the kernel threads of the POWERLINK master station based on the non-real-time operating system Linux with Xenomai kernel threads. Among them, the Xenomai kernel thread runs in the kernel layer of the operating system of the POWERLINK master station. Specifically, the Xenomai kernel thread is initialized, and at the same time, the relevant functions required for running the kernel thread are called, and the Xenomai kernel thread is run in the kernel layer of the Linux operating system.
[0031] Step 202: Replace the driver interface of the bottom layer module, the driver interface of the event queue module, and the driver interface of the top-level user module in the POWERLINK master station code based on the non-real-time operating system Linux with real-time driver interfaces. Specifically, when applying the Xenomai real-time kernel patch for the non-real-time operating system Linux based on the POWERLINK master station, the driver interface of the underlying module and the driver interface of the event queue module in the code of the POWERLINK master station based on the non-real-time operating system Linux The driver interfaces of the top-level user modules are all replaced with real-time driver interfaces, wherein the above-mentioned real-time driver interfaces are provided by the real-time driver module of the Xenomai real-time operating system; the underlying modules include: a network card driver module and a shared memory module. Specifically, call the functions related to the real-time driver interface of the Xenomai real-time operating system, and use these related functions to replace the original functions of the driver interface of each module in the POWERLINK master station. The new related functions after the replacement are run in the station, thus completing the replacement of the original driver interface of each module of the POWERLINK master station to the real-time driver interface.
[0032] The step division of the above method is only for the purpose of describing clearly, and can be combined into one step or split into some steps during implementation, and decomposed into multiple steps, as long as they contain the same logical relationship, they are all within the protection scope of this patent; Adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process is within the protection scope of this patent.
[0033] It is not difficult to find that this embodiment is a method example corresponding to the first embodiment, and this embodiment can be implemented in cooperation with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and are not repeated here in order to reduce repetition. Correspondingly, the related technical details mentioned in this embodiment can also be applied to the first embodiment.
[0034] Those skilled in the art can understand that all or part of the steps in the method of the above embodiments can be completed by instructing the relevant hardware through a program. The program is stored in a storage medium and includes several instructions to make a device (which may be a single-chip microcomputer) , chip, etc.) or a processor (processor) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, removable hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes.
[0035] Those of ordinary skill in the art can understand that the above-mentioned embodiments are specific examples for realizing the present invention, and in practical applications, various changes in form and details can be made without departing from the spirit and the spirit of the present invention. scope.
