An industrial field device and communication system supporting opc ua and time sensitive networking

Abstract

This application relates to industrial field devices and communication systems that support OPC UA and time-sensitive networking. The field devices include a programmable logic unit (PL) and a processing system unit (PS). The programmable logic unit (PL) and the processing system unit (PS) exchange data via an AXI bus. The processing system unit (PS) includes a user layer and a kernel layer. The user layer includes a data transmission program module, a network management program module, and a clock synchronization program module. The kernel layer includes a flow control module and a device driver module. The programmable logic unit (PL) includes a TSN network card logic module and a field device logic module. This application ensures the real-time and reliability of data transmission while enabling field devices to directly connect to a general-purpose network, helping to reduce wiring costs, improve network topology flexibility, and achieve plug-and-play for field devices.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of industrial internet, and particularly discloses an industrial field device supporting OPC UA and time-sensitive network and a communication system. BACKGROUND

[0002] The rise of IIoT and Industry 4.0 has completely changed the automation scene and put forward higher requirements for industrial communication. Industrial communication needs to meet the real-time and deterministic requirements of real-time control applications and the high-bandwidth requirements of industrial big data collection and analysis at the same time, and needs to be implemented in accordance with a unified and vendor-independent standard. In the field of industrial automation, there are various industrial Ethernet solutions, such as EtherCAT, Ethernet / IP, Profinet, etc. Despite having similar requirements and submarkets, these industrial Ethernet solutions are largely incompatible with each other, and some of them are incompatible with the classic Ethernet standard and cannot meet the requirements of modern manufacturing.

[0003] A next-generation industrial communication solution widely recognized by the industry at present is OPC UA over TSN. Time-sensitive network (TSN) is composed of a series of protocol families proposed by IEEE and is located at the data link layer of the open systems interconnection (OSI) model. TSN provides more reliable, low-latency and low-jitter data transmission services on the basis of traditional Ethernet and supports co-network transmission of IO and OT data. The open platform communication unified architecture (OPC UA) conforming to the IEC 62541 international standard is the only recommended solution for the implementation of the communication layer of the reference architecture model for industry 4.0 (RAMI4.0). OPC UA has been widely applied in the field of automation and provides a vendor-independent modeling method and can realize safe interoperability. Its Pub / Sub communication model can be well run on devices with limited resources. The combination of OPC UA and TSN can meet all the requirements of modern manufacturing for communication protocols and is expected to become a truly unified and single-standardized industrial communication method.

[0004] In recent years, many domestic and foreign universities, enterprises and related institutions have carried out researches on OPC UA and TSN, developed multiple switches supporting TSN technical standards, and tested controller-to-controller (C2C) data transmission based on OPC UA over TSN. However, current field devices mostly use several specific industrial Ethernet protocols to realize reliable transmission of production data. The scheme of integrating devices using incompatible protocols into the same network through an interface converter is costly and time-consuming, does not conform to the concept of "plug and play", and is difficult to realize unified controller-to-device (C2D) data transmission based on OPC UA and TSN. Therefore, it is necessary to design an industrial field device and communication system supporting OPC UA and time-sensitive network. SUMMARY

[0005] The embodiments of the present application aim to provide an industrial field device and communication system supporting OPC UA and time-sensitive network, and realize unified data transmission from sensor to cloud based on OPC UA TSN.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] In a first aspect, the embodiments of the present application provide an industrial field device supporting OPC UA and time-sensitive network, comprising a programmable logic unit PL and a processing system unit PS, the programmable logic unit PL and the processing system unit PS exchange data through an AXI bus, the processing system unit PS comprises a user layer and a kernel layer, the user layer includes a data transmission program module, a network management program module and a clock synchronization program module, the kernel layer includes a flow control module and a device driver module, the data transmission program module constructs a field device information model, processes OPC UA TSN messages, and exchanges data with external devices; the network management program module includes an LLDP server and a NETCONF server, the LLDP server announces device status and is used for automatic topology discovery, and the NETCONF server responds to queries of a centralized network configuration CNC and TSN-related configuration instructions; the clock synchronization program module is used for synchronizing between master and slave PTP hardware clocks and between PTP hardware clocks and system clocks; the flow control module maps traffic to different hardware queues and controls traffic out of queue according to rules; the device driver module provides an interface for upper-layer application programs to interact with PL hardware logic; the programmable logic unit PL is composed of a TSN network card logic module and a field device logic module, the TSN network card logic module includes a basic multi-queue network card logic, a PTP hardware clock and a TAS time-aware shaper; and the field device logic module manages corresponding field devices.

[0008] The data transmission program module uses the combination of OPC UA Pub / Sub and TSN to perform data transmission, realizes time-triggered many-to-many real-time communication, the Pub part of the data transmission program module publishes the state information of the field device to the external device, the Sub part receives the configuration / control information from the external device and makes corresponding response.

[0009] The network management program module uses the LLDP link layer discovery protocol to announce the device state, uses the NETCONF network management protocol to receive and respond to the query and configuration information from the centralized network configuration CNC, and models the data of the TSN card's gate list through the YANG data model.

[0010] The clock synchronization program module calculates the hardware clock deviation according to the IEEE 802.1AS standard, adjusts the local PTP hardware clock according to the calculation result, and synchronizes the system clock and the PTP hardware clock.

[0011] The flow control module uses the time-aware priority shaper TAPRIO queuing rule to realize the export scheduling of TSN flow, the TAPRIO queuing rule is configured through the flow control tool TC, and finally the configuration is mapped to the TSN card logic module.

[0012] The device driver module includes a network device driver and a character device driver interacting with the field device logic, provides an interface for the user layer application program to interact with the programmable logic unit PL card logic unit and the field device logic, and the constructed interface includes a network device interface, a PTP hardware clock interface and a field device interface.

[0013] In the second aspect, the embodiments of the present application provide an industrial field device communication system supporting OPC UA and time-sensitive network, including centralized user configuration CUC, centralized network configuration CNC, controller, TSN switch and field device as described above.

[0014] The centralized user configuration CUC collects flow requirements, which are summarized and then transmitted to the centralized network configuration CNC, the centralized network configuration CNC obtains the network topology, performs scheduling calculation, obtains the configuration information of each device, and according to the IEEE 802.1Qcc standard, the centralized network configuration CNC uses NETCONF and YANG model to distribute the configuration information to the TSN switch, controller and field device in the network.

[0015] Compared with the prior art, the application has the beneficial effects that: based on the ZYNQ SoC, an industrial field device and system supporting OPC UA and time-sensitive network are designed, the industrial field devices such as actuators and sensors are enabled to access the OPC UA TSN network, clock synchronization between devices and synchronization of software and hardware clocks in the device are realized through PTP, multi-to-multi data transmission between devices is realized through OPC UA Pub / Sub, TSN packets are marked through VLAN labels, and accurate sending of periodic time-sensitive packets is realized through hardware TAS export scheduling, and meanwhile, the device supports configuration of the TAS gating list based on NETCONF. In the scheme, the OPC UA TSN communication scheme independent of manufacturers and standardized is used, the real-time performance and reliability of data transmission are ensured, the field device can be directly connected to a general network, wiring cost is reduced, network topology flexibility is improved, and plug-and-play of the field device is realized. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0017] Figure 1 is a communication system schematic diagram of the embodiment of the present application;

[0018] Figure 2 is an industrial field device architecture diagram of the embodiment of the present application;

[0019] Figure 3 is a flow export scheduling schematic diagram of the embodiment of the present application;

[0020] Figure 4 is a NETCONF XML configuration information example of the embodiment of the present application;

[0021] Figure 5 is a TAPRIO Qdisc configuration example of the embodiment of the present application;

[0022] Figure 6 is a TSN network logical architecture diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described below in combination with the drawings in the embodiments of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0024] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0025] The terms "first", "second", and the like, do not denote any

[0026] As shown in Figure 1 An industrial field device communication system supporting OPC UA and time sensitive network, characterized by comprising a centralized user configuration CUC 1, a centralized network configuration CNC 2, a controller 3, a TSN switch 4 and a field device 5,

[0027] The centralized user configuration CUC 1 collects flow requirements, and after summarizing, delivers to the centralized network configuration CNC 2. The centralized network configuration CNC 2 obtains network topology, performs scheduling calculation, obtains configuration information of each device, and according to the IEEE 802.1Qcc standard, the centralized network configuration CNC 2 uses NETCONF and YANG model to deliver the configuration information to the TSN switch 4, the controller 3 and the field device 5 in the network. The controller 3 and the field device 5 can be flexibly accessed into the TSN network. The controller and the controller, and the controller and the field device realize reliable many-to-many communication based on OPC UA TSN.

[0028] As shown in Figure 2As shown, the embodiment of the present application provides an industrial field device supporting OPC UA and time sensitive network, comprising a programmable logic unit PL and a processing system unit PS, data is exchanged between the programmable logic unit PL and the processing system unit PS through an AXI bus, the processing system unit PS comprises a user layer and a kernel layer, the user layer comprises a data transmission program module, a network management program module and a clock synchronization program module, the kernel layer comprises a flow control module and a device driver module, the data transmission program module constructs a field device information model, processes OPC UA TSN messages, and exchanges data with external devices; the network management program module comprises an LLDP server and a NETCONF server, the LLDP server announces device status for automatic topology discovery, and the NETCONF server responds to queries of centralized network configuration CNC and TSN related configuration instructions; the clock synchronization program module is used to realize synchronization between master and slave PTP hardware clocks and between PTP hardware clocks and system clocks; the flow control module maps traffic to different hardware queues and controls traffic out of queue according to rules; the device driver module provides an interface for the upper layer application program to interact with the PL hardware logic; the programmable logic unit PL is composed of a TSN network card logic module and a field device logic module, the TSN network card logic module comprises a basic multi-queue network card logic, a PTP hardware clock and a TAS time-aware shaper; the field device logic module manages corresponding field devices.

[0029] The data transmission program module models OPC UA information according to the actual functions of the field device. Three sub-threads, data processing thread, pub thread and sub thread, are created. The data processing thread processes the received configuration / control information and updates the device status information; the pub thread directly constructs UADP messages, VLAN tags and MAC headers in the user layer through raw packet, and periodically sends messages through the nanosleep high-resolution sleep mechanism; the sub thread parses the received messages in the user layer through raw packet. TSN identification is constructed by filling VLAN ID and priority fields in the VLAN tag, and the VLAN priority takes values from 0 to 7, corresponding to eight different priority traffics. For the work of TAPTIO Qdisc, it is necessary to determine the categories of different traffics. The above data transmission program uses the socket option SO_PRIORITY to set the socket buffer (skb) priority, and the effective priority of skb has 16, which are 0-15. TAPTIO maps messages to different traffic categories according to the skb priority.

[0030] After the periodic time sensitive messages leave the application program, a set of software and hardware combined exit scheduling mechanism is used to ensure that the sending interval jitter of the messages does not exceed 1 microsecond, and a configurable sending time offset is realized, such asFigure 3 The NETCONF client in the CNC connects the NETCONF server of the field device, and issues port configuration information according to the result of the scheduling calculation. The NETCONF server parses the received configuration information, and if the configuration information is verified, the TC tool is called to configure the TAPRIO Qdisc according to the received configuration information. TAPRIO maps the packet to multiple traffic classes according to the configuration content, and allocates a sending queue for each traffic class. As shown in Figure 3 In the figure, the packet with priority 0, 1 and 2 is mapped to the No. 2 traffic class and enters the No. 2 exit queue, and the packet with priority 3 is mapped to the No. 1 traffic class and enters the No. 1 queue. The packet leaves the PS and enters the corresponding PL hardware queue, and TAPRIO configures the gate list of the TSN network card, and controls the opening and closing of the hardware queue gate according to the time slice. In the gate opening state, the packet is allowed to leave the queue and leave the network port through the transmission selection.

[0031] Currently, TAPRIO does not have a NETCONF API, and the NETCONF server completes the TAPRIO Qdisc configuration by converting the received configuration information into a TC instruction. Figure 4 The XML configuration request received by the NETCONF server is an example, and the NETCONF request creates three TAS time slots in the gate list by calling the sched:set-gate-states operation. After the NETCONF server verifies that the configuration information is correct, the TC tool is called to configure the TAPRIO Qdisc, and the configuration instruction and the configured gate list are as shown in Figure 5 According to the skb priority, the network packet is divided into four traffic classes and is allocated to four sending queues. The TAS gate list of the sending queue is created, and the gate period is 250us. The first time slot is 100us long, allowing queue 1 to be opened; the second time slot is 100us long, allowing queue 2 and queue 2 to be opened; and the third time slot is 50us long, allowing queue 3 to be opened.

[0032] In addition to the basic multi-queue network card function, the TSN network card logic module also implements the PTP function according to the IEEE 802.1AS standard, and implements the TAS function according to the IEEE 802.1Qbv standard, and the architecture is as shown in Figure 6 The network card internally maintains a PTP hardware clock, which obtains the current time through the PTP clock when the packet leaves or enters the Ethernet MAC, which is used for the upper clock synchronization program calculation. The sending scheduler module includes the TAS exit scheduling function, which obtains the current time from the PTP clock and decides the opening and closing of the queue according to the gate list.

[0033] The industrial field device supporting OPC UA and time sensitive network constructed by the application can realize nanosecond clock synchronization, and the sending interval jitter of periodic time sensitive message is not more than 1 microsecond.

[0034] The above merely provides an example of the application, and is not intended to limit the protection scope of the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. An industrial field device supporting OPC UA and time-sensitive networking, characterized in that: It includes a programmable logic unit PL and a processing system unit PS. The programmable logic unit PL and the processing system unit PS exchange data via an AXI bus. The processing system unit PS includes a user layer and a kernel layer. The user layer includes a data transmission program module, a network management program module, and a clock synchronization program module. The kernel layer includes a flow control module and a device driver module. The data transmission program module builds a field device information model, processes OPC UA TSN messages, and exchanges data with external devices. The network management program module includes an LLDP server and a NETCONF server. The LLDP server notifies the device status for automatic topology discovery, and the NETCONF server responds to queries from the centralized network configuration CNC and TSN-related configuration instructions. The clock synchronization program module is used to achieve synchronization between the master and slave PTP hardware clocks and between the PTP hardware clock and the system clock; The traffic control module maps traffic to different hardware queues and controls traffic dequeueing according to rules; the device driver module provides an interface for upper-layer applications to interact with the PL hardware logic; the programmable logic unit PL consists of a TSN network card logic module and a field device logic module. The TSN network card logic module contains basic multi-queue network card logic, PTP hardware clock, and TAS time-aware shaper; the field device logic module manages the corresponding field devices.

2. The industrial field device supporting OPC UA and time-sensitive networking according to claim 1, characterized in that: The data transmission program module uses a combination of OPC UA Pub / Sub and TSN for data transmission, realizing time-triggered many-to-many real-time communication. The Pub part of the data transmission program module publishes the status information of the field device to the external device, and the Sub part receives the configuration / control information from the external device and makes corresponding responses.

3. The industrial field device supporting OPC UA and time-sensitive networking according to claim 1, characterized in that: The network management program module uses the LLDP link layer discovery protocol to announce the device status, uses the NETCONF network management protocol to receive and respond to queries and configuration information from the centralized network configuration CNC, and uses the YANG data model to model the gate control list of the TSN network card.

4. The industrial field device supporting OPC UA and time-sensitive networking according to claim 1, characterized in that: The clock synchronization program module calculates the hardware clock deviation according to the IEEE 802.1AS standard, adjusts the local PTP hardware clock according to the calculation result, and simultaneously adjusts the system clock to synchronize with the PTP hardware clock.

5. The industrial field device supporting OPC UA and time-sensitive networking according to claim 1, characterized in that: The traffic control module uses the time-aware priority shaper TAPRIO queuing discipline to implement the egress scheduling of TSN traffic. The TAPRIO queuing discipline is configured through the traffic control tool TC, and the configuration is finally mapped to the TSN network card logic module.

6. The industrial field device supporting OPC UA and time-sensitive networking according to claim 1, characterized in that: The device driver module includes a network device driver and a character device driver that interacts with the field device logic, providing an interface for user-layer applications to interact with the programmable logic unit PL network card logic unit and the field device logic. The constructed interface includes a network device interface, a PTP hardware clock interface and a field device interface.

7. An industrial field device communication system supporting OPC UA and time-sensitive networking, characterized in that: The invention comprises a centralized user configuration CUC (1), a centralized network configuration CNC (2), a controller (3), a TSN switch (4) and a field device (5) as claimed in any one of claims 1 to 6, The centralized user configuration CUC (1) collects flow requirements, summarizes them and passes them to the centralized network configuration CNC (2). The centralized network configuration CNC (2) obtains the network topology, performs scheduling calculations, and obtains configuration information of each device. According to the IEEE802.1Qcc standard, the centralized network configuration CNC (2) uses NETCONF and YANG models to send the configuration information to the TSN switch (4), controller (3) and field device (5) in the network.

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