Method and system for establishing a communication link between an operating unit and a field device from automation engineering

Abstract

The invention comprises a method for establishing a communication link between an operating unit (BE) and a field device (FG) from automation engineering, wherein a framework application (RA) and a Bluetooth server (BS) are executed on the operating unit (BE), comprising: - connecting the operating unit (BE) to a Bluetooth gateway (BG) via a radio link (FV) by means of the Bluetooth server (BS) based on a Bluetooth protocol, wherein the Bluetooth gateway (BG) is connected to the field device (FG) via a communication network (KN); - establishing and executing a tunnel functionality between the framework application (RA) and the Bluetooth gateway (BG); - sending information about the field device (FG) from the Bluetooth gateway (BG) to the framework application (RA) via the radio link (FV), wherein the information contains identification information of the field device (FG) and information about a communication protocol used by the communication network (KN); and - instantiating a device driver (GT) for the field device (FG) and a communication driver (KT) based on the information about the field device (FG), wherein the device driver (GT) together with the communication driver (KT) creates commands and / or queries to the field device (FG) in a format which complies with the communication protocol. The invention also relates to a system designed to carry out the method according to the invention.

Description

[0001] Method and system for establishing a communication connection between an operating unit and a field device in automation technology

[0002] The invention relates to a method for establishing a communication connection between an operating unit and a field device in automation technology. Furthermore, the invention relates to a system configured to implement the method according to the invention.

[0003] Field devices used in industrial plants are already known from the state of the art. Field devices are widely used in process automation technology as well as in manufacturing automation technology. Field devices essentially refer to all devices used close to the process and that provide or process-relevant information. Field devices are used to record and / or influence process variables. Measuring devices or sensors are used to record process variables. These are used, for example, for pressure and temperature measurement, conductivity measurement, flow measurement, pH measurement, level measurement, etc. and record the corresponding process variables such as pressure, temperature, conductivity, pH value, level, flow, etc. Actuators are used to influence process variables.These include, for example, pumps or valves that can influence the flow of a fluid in a pipe or the fill level in a container. In addition to the previously mentioned measuring devices and actuators, field devices also include remote I / Os, wireless adapters, and generally devices located at the field level.

[0004] A large number of such field devices are produced and distributed by the Endress+Hauser Group.

[0005] In modern industrial plants, field devices are usually connected to higher-level units via communication networks such as fieldbuses (Profibus®, Foundation® Fieldbus, HART®, etc.). These higher-level units are usually control systems (DCS) or control units, such as a PLC (programmable logic controller). The higher-level units are used, among other things, for process control, process visualization, process monitoring and for commissioning the field devices. The measured values ​​recorded by the field devices, particularly sensors, are transmitted via the respective bus system to one (or possibly several) higher-level units. In addition, data transmission from the higher-level unit to the field devices via the bus system is also required, particularly for the configuration and parameterization of field devices and for controlling actuators.The integration of field devices into object-based configuration or management systems is achieved through device descriptions, which ensure that the higher-level units can recognize and interpret the data provided by the field devices. The device descriptions are provided for each field device type or for each field device type in different applications by the respective device manufacturer. In order for the field devices to be integrated into different fieldbus systems, it is also important to note that different device descriptions must be created for the different fieldbus systems. For example, there are HART, Fieldbus Foundation, and Profibus device descriptions.

[0006] In order to create a uniform description for field devices, the Fieldbus Foundation (FF), the HART Communication Foundation (HCF) and the Profibus User Organization (PNG) have created a uniform electronic device description (EDD); this is defined in the IEC 61804-2 standard.

[0007] For comprehensive operation of field devices, special device descriptions, known as DTMs (Device Type Managers), have recently become available. These devices comply with the FDT (Field Device Tool) specifications. The FDT specification, considered the industry standard, was developed by the PNO (Profibus User Organization) in collaboration with the ZVEI (German Electrical and Electronic Manufacturers' Association). The latest FDT specifications are available from the ZVEI, the PNO, or the FDT Group.

[0008] Many field device manufacturers already supply the corresponding DTMs with their field devices. The DTMs contain all device-specific data, functions, and operating rules, such as the device structure, available communication options, and the graphical user interface (GUI) for a specific field device or field device family.

[0009] The DTMs require a frame application, in this case the FDT frame, as their runtime environment. The frame application and the corresponding DTMs allow very convenient access to field devices, e.g., to device parameters, measured values, diagnostic information, status information, etc., as well as the calling of special functions available to individual DTMs. The frame application and DTMs together form a subcomponent-based management or configuration system for field devices. To ensure that DTMs from different manufacturers function correctly in the frame application, the interfaces to the frame application and to the other DTMs must be clearly defined. This interface definition is represented by the abbreviation FDT. FDT technology standardizes the communication interface between field devices and the higher-level unit.What's special about this technology is that it works independently of the communication protocol used and the respective software environment of both the field device and the higher-level system. FDT enables any field device to be addressed via any higher-level system using any communication protocol. A well-known FDT framework, for example, is "FieldCare," distributed by the Endress+Hauser Group.

[0010] A communication driver (CommDTM) is integrated into the frame application like the device drivers. It ensures that the operating commands or requests generated by a device driver to a field device are converted into the corresponding communication protocol of the fieldbus network.

[0011] Mobile control units can also be used to operate field devices that have implemented an FDT framework application. For example, there are control units that are connected to the fieldbus network. However, it is also possible to operate the control unit via a second data channel (the first data channel being the fieldbus network). For example, the control unit is connected to the field device via a wired access point via a special service interface on the field device. The field devices marketed by the applicant, for example, use the proprietary CDI ("Common Data Interface") standard for this purpose.

[0012] The control unit can also communicate with the field devices via a wireless communication connection, particularly based on a Bluetooth standard. The applicant produces and sells devices known as Bluetooth gateways that allow the control units to be connected to the field devices. The field device is connected to a Bluetooth gateway via a wired connection, particularly using the HART or CDI communication standards.

[0013] However, wireless configuration of field devices can only be performed over TCP / IP using standard FDT / DTM technology, provided a communication DTM is available. Currently, there is no communication driver that can communicate with Bluetooth gateways using encrypted Bluetooth communication.

[0014] This makes it impossible to configure field devices connected to the Bluetooth gateway via HART or CDI using an operating unit with an FDT frame application. Based on this problem, the invention aims to enable the operation of a field device using FDT technology over a Bluetooth connection.

[0015] The object is achieved by a method according to claim 1 and by a system according to claim 8.

[0016] With regard to the method, it is provided that the method serves to establish a communication connection between an operating unit and a field device of automation technology, wherein a frame application and a Bluetooth server are executed on the operating unit, wherein the method comprises the following method steps: connecting the operating unit to a Bluetooth gateway via a radio connection by means of the Bluetooth server based on a Bluetooth protocol, wherein the Bluetooth gateway is connected to the field device via a communication network;

[0017] Establish and execute a tunnel functionality between the framework application and the Bluetooth gateway;

[0018] Sending information about the field device from the Bluetooth gateway to the framework application via the radio connection, wherein the information includes identification information of the field device and information about a communication protocol used by the communication network; and instantiating a device driver for the field device and a communication driver based on the information about the field device, wherein the device driver, together with the communication driver, creates commands and / or queries to the field device in a format compliant with the communication protocol.

[0019] According to the invention, the framework application, which is particularly designed according to the FTD / DT standard, opens a tunnel functionality with the underlying field device after connecting to the Bluetooth gateway. Based on information that the Bluetooth gateway maintains about the field device or queries it, the framework application obtains knowledge of the type of field device and the communication protocol of the communication connection established between the Bluetooth gateway and the field device. This knowledge is used by the framework application to instantiate a communication driver matching the communication protocol of the communication connection established between the Bluetooth gateway and the field device, and a device driver matching the field device.The control unit communicates with the underlying Bluetooth gateway via the communication driver using tunnel functionality. This communication path is completely transparent to the user. To communicate with Bluetooth devices, the framework application uses a Bluetooth server, an existing software component. Bluetooth devices can be configured via this Bluetooth server.

[0020] The advantage of the method according to the invention is that neither the existing communication drivers nor the existing device drivers for the field devices need to be modified. The method according to the invention requires only minor changes to the framework application to enable the use of the tunnel functionality as soon as a Bluetooth gateway with corresponding field devices connected to this Bluetooth gateway is available. From the user's perspective, there is no difference compared to previous communication drivers and device drivers. The communication driver communicates with the Bluetooth gateway, since the new tunnel functionality tunnels telegrams within the Bluetooth telegrams in accordance with the communication protocol of the communication connection established between the Bluetooth gateway and the field device.

[0021] The method according to the invention advantageously utilizes FDT / DTM technology. Accordingly, the framework application is an FDT framework application. The device driver is a DTM (Device Type Manager). The communication driver is a CommDTM.

[0022] Field devices mentioned in connection with the invention have already been listed as examples in the introductory part of the description.

[0023] According to one embodiment of the method, the tunnel functionality comprises: i. embedding the commands and / or queries in first Bluetooth telegrams by means of the Bluetooth server; ii. transmitting the first Bluetooth telegrams from the Bluetooth server to the Bluetooth gateway via the radio connection; iii. extracting the commands and / or queries from the first Bluetooth telegrams by means of the Bluetooth gateway; and iv. transmitting the extracted commands and / or queries from the Bluetooth gateway to the field device via the communication network.

[0024] The Bluetooth server is thus extended by a new communication protocol, the

[0025] Tunnel functionality, which allows telegrams to be tunneled through the existing Bluetooth communication in compliance with the communication protocol of the established communication connection between the Bluetooth gateway and the field device. "Tunneling" means that the telegrams are embedded in Bluetooth telegrams without changing the structure or layout of the telegrams, for example, with regard to the preambles and / or the payload portion. After extracting the telegrams from the Bluetooth telegram, the telegram remains unchanged. This allows the existing framework application and modern device and communication drivers to be used to configure field devices connected to the Bluetooth gateway.

[0026] A further embodiment of the method provides the following method steps: Creating responses to the commands and / or queries in accordance with the communication protocol by the field device, wherein the tunnel functionality further comprises: v. Embedding the responses in second Bluetooth telegrams using the Bluetooth gateway; vi. Transmitting the second Bluetooth telegrams from the Bluetooth gateway to the Bluetooth server via the radio connection; vii. Extracting the responses from the second Bluetooth telegrams using the Bluetooth server; and viii. Transmitting the extracted responses from the Bluetooth server to the device driver.

[0027] The procedural steps regarding the response correspond to those of the command or request path, whereby the Bluetooth server of the frame application and the Bluetooth gateway exchange the functionalities (embedding and extracting) accordingly.

[0028] According to an advantageous embodiment, the method provides that the information about the field device includes a network address of the field device in the communication network. The network address is negotiated between the Bluetooth gateway and the field device according to the communication protocol used. The framework application communicates this network address to the communication driver, which addresses the telegrams to this network address. This is advantageous because the communication driver must, by default, search the entire range of possible network addresses, which is now no longer necessary. Experience shows that this step can otherwise take up to approximately ten minutes on average. In a further development of the method, the Bluetooth server searches for reachable Bluetooth gateways before the connecting step.If accessible Bluetooth gateways are found, the field devices connected to the respective Bluetooth gateways are listed in the framework application. The operator then selects one of the field devices listed in the list. This initiates the method according to the invention, beginning with the step of connecting the Bluetooth server to the corresponding Bluetooth gateway to which the selected field device is connected.

[0029] With regard to the system, it is intended that this system is designed to carry out the method and comprises the following components:

[0030] An operating unit, wherein a frame application and a Bluetooth server are executed on the operating unit;

[0031] A Bluetooth gateway;

[0032] A field device, where the Bluetooth gateway is connected to the field device via a communication network.

[0033] The control unit is, in particular, a control unit within the meaning of the “Field Xperts” marketed by the applicant or a mobile device, for example a tablet or a smartphone.

[0034] The Bluetooth gateway is a component which has two communication interfaces, wherein one of the communication interfaces sends and receives Bluetooth telegrams and wherein the other of the two communication interfaces receives and sends telegrams in accordance with the communication protocol of the communication connection established between the Bluetooth gateway and the field device.The Bluetooth gateway further includes an electronic unit for creating Bluetooth telegrams and telegrams compliant with the communication protocol of the communication connection established between the Bluetooth gateway and the field device, embedding telegrams received from the field device compliant with the communication protocol of the communication connection established between the Bluetooth gateway and the field device into Bluetooth telegrams, and extracting telegrams compliant with the communication protocol of the communication connection established between the Bluetooth gateway and the field device from Bluetooth telegrams received from the Bluetooth server.

[0035] According to an advantageous embodiment of the system, the communication protocol used for communication between the Bluetooth gateway and the field device is a HART protocol or a proprietary communication protocol. In particular, the proprietary protocol is the CDI protocol, which is used by the applicant's field devices.

[0036] A further advantageous embodiment of the system provides that the Bluetooth protocol is a Bluetooth LE protocol.

[0037] The invention is explained in more detail with reference to the following figure. It shows

[0038] Fig. 1 : an embodiment of the method according to the invention.

[0039] The method according to the invention allows the establishment of a communication connection between a field device (FG) and a control unit (BE) via a Bluetooth communication connection. A framework application (RA), in particular an FDT framework application, is executed on the control unit (BE), which is in particular a mobile device in the form of a tablet or smartphone.

[0040] The field device FG is connected to a Bluetooth gateway BG via a communication network KN. The communication network KN is configured according to the HART protocol or a proprietary protocol, in particular the CDI ("Common Data Interface") protocol used by the applicant's field devices. The Bluetooth gateway BS acts as the master, and the field device FG acts as the slave.

[0041] The process begins by starting the RA framework application on the BE control unit. At the same time, a Bluetooth server (BS) is started. The Bluetooth server (BS) creates, sends, and receives Bluetooth telegrams via a communication interface (KS) on the BE control unit. The Bluetooth server (BS) can be part of the RA framework application or run as a separate component on the BE control unit.

[0042] The Bluetooth server (BS) initiates a search for nearby Bluetooth-enabled devices. If compatible Bluetooth gateways (BG) are found, the framework application (RA) provides a device list with all Bluetooth gateways (BG) found within Bluetooth range.

[0043] If a Bluetooth gateway GB is present and a field device FG is connected to it, the device list displays the data of the connected field device FG, in particular the device tag, the field device type, and / or the field device symbol. The user selects the field device FG from the device list in the frame application RA, whereupon the Bluetooth server BS begins to connect to the Bluetooth gateway BG according to the Bluetooth protocol. After establishing a radio connection FV, the Bluetooth server BS checks whether the Bluetooth gateway BG connected via Bluetooth supports establishing a tunnel function and whether the field device FG is actually connected.

[0044] If this is the case, the Bluetooth server (BS) then opens the tunnel functionality together with the Bluetooth gateway. Information about the connected field devices is sent from the Bluetooth gateway (BG) to the framework application (RA).

[0045] The framework application RA then instantiates a device driver GT matching the field device FG and a communication driver KT matching the protocol of the communication network KN based on the information. The device driver GT is specifically a DTM and encapsulates all field device-specific functionalities and commands. It enables the creation of commands or requests matching the type of field device FG and the processing of the responses from the field device FG. The communication driver KT is specifically a CommDTM and enables the conversion of the commands or requests into telegrams compliant with the protocol of the communication network KN.

[0046] The established tunnel functionality is described below:

[0047] The user begins by configuring the underlying field device FG using the device driver GT. For example, they select a parameter value of the field device FG that they want to change. The device driver GT creates an operating command for the field device FG, and the communication driver creates a corresponding telegram in the format of the communication network KN protocol, which contains the operating command. The operating command is transferred from the device driver GT to the communication driver KT via an internal FDT interface IS of the frame application RA. The communication driver KT transfers the created telegram to a special interface, a virtual COM port. The communication driver KT is designed to transfer the telegram to an actual COM port, which then transmits the telegram via the actual communication network KN.In the method according to the invention, the virtual COM port simulates an actual COM port, which forwards the telegram to the Bluetooth server. This way, the system consisting of the device driver GT and communication driver KT does not need to be modified.

[0048] The Bluetooth server embeds the telegram passed by the communication driver KT into a first Bluetooth telegram and transmits this first Bluetooth telegram to the Bluetooth gateway BG via the established radio connection FV. The Bluetooth gateway BG extracts the telegram containing the operating command from the first Bluetooth telegram and transmits this telegram, now in the correct protocol, over the communication network to the field device FG.

[0049] The field device FG processes the operating command, sets the new parameter value and creates a response telegram containing a confirmation message.

[0050] The field device FG sends the response telegram, which has the format of the communication network protocol KN, to the Bluetooth gateway via the communication network. The Bluetooth gateway BG embeds the response telegram in a second Bluetooth telegram and transmits it to the Bluetooth server BS via the radio connection FV.

[0051] The Bluetooth server extracts the response telegram from the second Bluetooth telegram and transmits the response telegram to the communication driver via the virtual COM port (COM). The communication driver extracts the confirmation message from the response telegram and transmits the confirmation message to the device driver (GT) via the internal FDT interface (IS).

[0052] The device driver GT processes the confirmation message and causes the confirmation message to be communicated to the user via the frame application RA, in particular visually.

[0053] List of reference symbols

[0054] BE Control unit BG Bluetooth gateway BS Bluetooth server COM Virtual COM port FG Field device FV Radio connection GT Device driver IS Internal interface KN Communication network KS Communication interface KT Communication driver RA Frame application

Claims

Patent claims 1 . Method for establishing a communication connection between an operating unit (BE) and a field device (FG) of automation technology, wherein a frame application (RA) and a Bluetooth server (BS) are executed on the operating unit (BE), comprising: Connecting the control unit (BE) to a Bluetooth gateway (BG) via a radio connection (FV) by means of the Bluetooth server (BS) based on a Bluetooth protocol, wherein the Bluetooth gateway (BG) is connected to the field device (FG) via a communication network (KN); Establish and execute a tunnel functionality between the framework application (RA) and the Bluetooth gateway (BG); Sending information about the field device (FG) from the Bluetooth gateway (BG) to the frame application (RA) via the radio connection (FV), wherein the information contains identification information of the field device (FG) and information about a communication protocol used by the communication network (KN); and Instantiating a device driver (GT) for the field device (FG) and a communication driver (KT) based on the information about the field device (FG), wherein the device driver (GT) together with the communication driver (KT) creates commands and / or queries to the field device (FG) in a format compliant with the communication protocol.

2. The method according to claim 1, wherein the tunnel functionality comprises: i. embedding the commands and / or queries in first Bluetooth telegrams by means of the Bluetooth server (BS); ii. transmitting the first Bluetooth telegrams from the Bluetooth server (BS) to the Bluetooth gateway (BG) via the radio connection (FV); iii. extracting the commands and / or queries from the first Bluetooth telegrams by means of the Bluetooth gateway (BG); and iv. transmitting the extracted commands and / or queries from the Bluetooth gateway (BG) to the field device (FG) via the communication network (KN).

3. The method of claim 2, further comprising: Creating responses to the commands and / or queries in accordance with the communication protocol by the field device (FG), wherein the tunnel functionality further comprises: v. Embedding the responses in second Bluetooth telegrams by means of the Bluetooth gateway (BG); vi. Transmitting the second Bluetooth telegrams from the Bluetooth gateway (BG) to the Bluetooth server (BS) via the radio link (FV); vii. Extracting the responses from the second Bluetooth telegrams by means of the Bluetooth server (BS); and viii. Transmitting the extracted responses from the Bluetooth server (BS) to the device driver (GT).

4. Method according to one of the preceding claims, wherein the information about the field device (FG) comprises a network address of the field device (FG) in the communication network (KN).

5. Method according to one of the preceding claims, wherein the Bluetooth server (BS) searches for reachable Bluetooth gateways (BG) before the connecting step.

6. The method according to claim 5, wherein, if reachable Bluetooth gateways are found, the field devices (FG) connected to the respective Bluetooth gateways (BG) are maintained in a list in the frame application (RA).

7. The method according to claim 6, wherein one of the field devices (FG) listed in the list is selected and the method is then started beginning with the step of connecting the Bluetooth server (BS) to the corresponding Bluetooth gateway (BG) to which the selected field device (FG) is connected.

8. System designed to carry out the method according to one of claims 1 to 7, comprising: An operating unit (BE), wherein a frame application (RA) and a Bluetooth server (BS) are implemented on the operating unit (BE); A Bluetooth gateway (BG); A field device (FG), where the Bluetooth gateway (BG) is connected to the field device (FG) via a communication network (CN).

9. The system of claim 8, wherein the communication protocol is a HART protocol or a proprietary communication protocol.

10. The system of claim 8 or 9, wherein the Bluetooth protocol is a Bluetooth LE protocol. 5

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