Fieldbus-transmitted control instructions for field devices

Abstract

Diagnostic module (DM) for the technical diagnosis of field devices (FG) of an automation system (AA), including: - To exchange control and / or regulation data between a local control unit (PLC) that has a fieldbus interface and is not configured with the cloud-based server (S); - At least one field device (FG); - A coupling module (GW) integrated into the field device (FG) with: o A web interface (WS-GW) for data communication with a cloud-based server (S) and for receiving an analysis message (ant) from the cloud-based server (S); ◯ A conversion module (UM) for generating a fieldbus message (fn) from the received analysis message (ant) and for sending the fieldbus message (fn) to the control unit (PLC); - A fieldbus (B) for internal communication between the devices of the automation system (AA) and for forwarding the generated fieldbus message (fn) to the control unit (PLC) for controlling the automation system (AA).

Description

[0001] The present invention relates to the technical diagnosis of field devices in an automation system, e.g. in a production plant with actuators and sensors, and relates in particular to a diagnostic module, a diagnostic system, a method and a computer program.

[0002] Field devices in various types of automation systems are subject to stringent requirements regarding quality, robustness, and availability. A failure or malfunction of a field device in a process can incur extremely high costs, especially if it results in a production stoppage. Therefore, significant technical effort is invested in field devices to substantially reduce the risk of malfunctions or to enable them to independently detect and report defects. Functions are integrated into the field device with multiple redundancies, and measurement results are continuously monitored and verified internally. The requirements for the reliability of the field device increase with its application (e.g., in nuclear power plants). Monitoring field devices must therefore ensure that the devices involved function flawlessly and that a failure is detected as early as possible, ideally before a malfunction occurs.

[0003] For this monitoring and analysis task, predictive maintenance methods are used, which analyze a large amount of monitoring data from the field devices. These methods are often based on predictive maintenance algorithms. These algorithms must process a large volume of data and require high computing power with corresponding additional technical resources (memory, etc.).

[0004] It is known in the prior art to outsource this computationally intensive analysis task to an external computing unit, particularly to the cloud, which is connected to the automation system via the internet or a web interface. EP 3 070 548 A2 provides an example of such a system. However, this document disadvantageously requires that the local controllers on the automation system be cloud-enabled or have cloud connectivity.

[0005] DE 10 2017 215 508 A1 discloses an automation system that is extended via an application interface.

[0006] However, if older systems need to be monitored that are equipped with controllers which do not yet have cloud connectivity, or do not yet have it fully, then the important monitoring task cannot be performed and applied. This poses a problem.

[0007] Based on this, the present invention addresses the technical problem of presenting an approach with which even "old" local control components, such as PLCs, which do not have cloud connectivity, can be monitored by a cloud-based server. The aim is to expand the monitoring capabilities and make the automation system more reliable overall.

[0008] This problem is solved by a diagnostic module for the technical diagnosis of field devices that can be operated in an automation system according to claim 1.

[0009] The diagnostic module is equipped with a local control unit (such as a PLC) that has a fieldbus interface, e.g., PROFINET. However, the control unit is not web-enabled or has an external interface to, for example, a cloud-based server (especially for receiving data such as control and / or diagnostic data). To enable such control units to be addressed by a cloud server, the automation system, and in particular the diagnostic module, includes a coupling module (e.g., an IoT gateway) for a number of field devices. The coupling module has a web interface (which can be implemented as a GUI or a web service, for example) for data communication with a cloud-based server and, in particular, for receiving an analysis message (representing a result of a predictive maintenance analysis algorithm) from the cloud-based server.The coupling module further includes a conversion module for generating a fieldbus message from the received analysis message. The coupling module can be configured to send the generated fieldbus message to the control unit, or it can instruct another transmission module to do so. A fieldbus serves for internal communication between the devices of the automation system and, in particular, for forwarding the generated fieldbus message to the control unit for monitored control of the automation system. In a preferred embodiment of the invention, at least one of the field devices can be equipped with such a coupling module and thus have an external interface to the cloud-based server.

[0010] The invention offers the technical advantage that even older controllers lacking web connectivity can be integrated into a server-based monitoring procedure. This increases reliability and improves control quality. This is preferably achieved by enabling field devices already used in the system to transmit diagnostic messages in the form of analysis messages from the cloud or server to the actuators / sensors and / or field devices connected to the system via standard fieldbus messages and related data exchange mechanisms. This allows for the initiation of further diagnostic and / or troubleshooting measures. The coupling module can be implemented on one of the field devices, but this is not mandatory.

[0011] According to the invention, the coupling module is integrated into the field device. This reduces component costs, increases reliability, and lowers the space requirement.

[0012] In a preferred embodiment of the invention, the control unit, the at least one field device, and the coupling module are connected via the fieldbus for data transmission. This is a bus system, preferably according to the standard IEC 61158 (Industrial communication networks - Fieldbuses) or according to another standard (e.g., Real-time Ethernet).

[0013] In another aspect, the invention relates to a diagnostic system for the technical diagnosis of field devices, as claimed. The diagnostic system is equipped with a diagnostic module as described above and additionally includes a cloud server that is connected to the diagnostic module via a web interface. The cloud server can be configured for various tasks, in particular for executing a predictive maintenance algorithm.

[0014] According to a preferred embodiment of the diagnostic system, the server has a web interface and includes a processor, wherein the processor is configured to execute a predictive maintenance algorithm that calculates an analysis message from monitoring data acquired on the field devices and transmitted to the server.

[0015] The solution to the problem has been described above with reference to the devices (diagnostic module, system). Features, advantages, or alternative embodiments mentioned in this context are also transferable to the other claimed items and vice versa. In other words, the method and the computer program can also be further developed with the features described and / or claimed in connection with the module or system. The corresponding functional features of the method are thereby implemented by corresponding physical modules, in particular hardware modules or microprocessor modules, of the system or product, and vice versa.

[0016] In another aspect, the invention relates to a method for diagnosing field devices according to claim 6.

[0017] The diagnostic procedure includes the following steps: - Sending monitoring data from the field devices (which participate in the diagnostic procedure and are connected to the fieldbus) to a coupling module that serves as a gateway and is integrated into the field device; - Initiating the transmission of monitoring data from the coupling module to a cloud-based server; - Preparing or triggering the execution of a predictive maintenance algorithm on the server based on the received monitoring data to generate an analysis message; - Receiving the generated analysis message on the coupling module; - Sending the analysis message from the coupling module to an implementation module; - Generation of a fieldbus message from the analysis message by the implementation module; - Sending the fieldbus message from the conversion module to a local control unit for modified control of the automation system based on the fieldbus message, whereby the local control unit (PLC) is not configured to exchange control and / or regulation data with the cloud-based server (S).

[0018] In a preferred embodiment of the method, process data is also acquired on the field device in addition to the monitoring data. The process data can be prepared for transmission to the server. The process data can be processed and / or temporarily stored on the server. When the analysis message is sent from the server to the coupling module, the process data can be appended to or integrated into the analysis message either directly (from the temporary storage in unprocessed form) or in processed form. "In processed form" here refers to further processing of the process data, which can be performed client-side (in modules in the field, e.g., for aggregating process data) and / or server-side and serves, among other things, to calculate a diagnostic message. The diagnostic message can, for example, include statistical analyses.Alternatively, a message package can be created from the process data together with the analysis message and transmitted to the coupling module. This has the advantage that the controller gains access to process data from field devices or other devices or components of the automation system, albeit indirectly via the server, even though the controller lacks web connectivity. In principle, the process data could also be sent directly to other field devices via the fieldbus – but then in unprocessed form. When process data is sent indirectly from field devices to other controllers and / or field devices by transmitting it to the server, which thus acts as an intermediary processing node, the process data can be processed. In other words, manipulated process data is appended to the analysis message, or a message package containing manipulated process data is generated.The manipulation can include, for example, a time-based evaluation, a comparison with reference values, or an indication of how the process data compares statistically (e.g., compared to an average). Preferably, the process data can only be transmitted to selected field devices, especially those that generate process data of the same type (e.g., process data from an end-position sensor is only transmitted to other end-position sensors and not, for example, to temperature sensors). Processing on the cloud server can also be used to generate additional input / output data (as manipulated process data), which is preferably transmitted to the controller (e.g., PLC) together with the normal process data.

[0019] In a further, preferred embodiment of the method, several field devices participate in the diagnostic procedure. The field device is thus one of a set of field devices. To uniquely assign the messages to be exchanged (monitoring data, analysis message) to the (correct) field device, an identification mechanism is required to authenticate the respective message or data. For this purpose, an identifier can be used that is linked to the respective data to be transmitted (e.g., monitoring data), so that the server can distinguish the monitoring data according to its origin and assign it to a specific field device. This allows the server to process the acquired monitoring data in a field-device-specific manner and to generate the analysis messages in a field-device-specific way as well.The analysis message can be linked to the identifier in a suitable manner (as described above) so that the coupling module receives the respective analysis message along with the identifier and can then transmit it specifically to the field device identified by the identifier. This is useful, for example, if a particular field device has been analyzed (through the analysis on the server) as faulty or likely to be faulty, and this message should be transmitted immediately and directly to the respective field device, for example, to issue a local warning. The analysis message can also be forwarded to the controller; however, this is not mandatory.

[0020] In a further preferred embodiment of the method, the analysis message is directly output upon receipt on the diagnostic module and, in particular, on the field device that has been identified via the identifier. This can preferably be done, for example, optically (e.g., using an LED) or in another form. This allows for an even faster and more direct response to the server-side analysis at the field device.

[0021] In a further preferred embodiment of the method, the predictive maintenance algorithm processes not only the monitoring data acquired by the field devices but also historical data and / or reference data (e.g., from other field devices) to generate the analysis message. This allows for a more comprehensive analysis and makes the analysis result, in the form of the analysis message, even more reliable.

[0022] In a further, preferred embodiment of the method, the predictive maintenance algorithm has preconfigured functionality and serves to calculate diagnostic data. A predictive maintenance algorithm can preferably be used for this purpose. One advantage is that the maintenance of the system can be managed via the cloud or a cloud-based server. In a first embodiment, the predictive maintenance algorithm can be configured as a switching cycle counter and determine (count) data locally in the field device, while its evaluation is not performed locally and preferably in the cloud. The field device counts the number of switching cycles of an output. These switching cycles can then be assigned to a specific cylinder in the system.The data collected by the field device is transmitted to the server in the cloud, where, based on additional application information, limit values ​​can be adaptively determined. If the algorithm in the cloud detects that maintenance is required, this is transmitted to the field device via an analysis message. The field device can then generate a diagnostic message for the controller / PLC. The algorithm can thus be executed in the cloud and has enhanced knowledge about the installed cylinder and the application. With this knowledge (in the form of data sets), calculations can be performed centrally in the cloud to determine, for example, whether a cylinder replacement is necessary based on the number of driving cycles. The need for replacement can then be sent from the cloud, via the intermediary node / device, to the non-cloud-enabled application (on the control unit).A second embodiment relates to monitoring the travel time of a cylinder. As described in the first embodiment, the corresponding (here, time) signals are acquired locally and transmitted to the cloud server. In the cloud, the relevant measured values ​​from the field device are evaluated. In a further development, not only the switching cycles but also the corresponding travel times of a cylinder can be acquired and sent to the cloud or server for evaluation. In other further developments, the server can detect deviations and changes over a longer period. This proves particularly advantageous when additional system data, such as temperature, vibration, operating times, etc., are acquired and taken into account. The predictive maintenance algorithm on the server can evaluate whether the system is in a normal state, whether it is due to wear and tear, or even whether the component has actually failed.In the event of a detected failure, it is advantageous to send a corresponding diagnostic message (e.g., as part of the analysis message) with localization information (regarding the defective component) directly to the controller or PLC.

[0023] A key characteristic of field-level diagnostics is that the application in the controller reacts directly to specific diagnostic events by immediately triggering processes on the machine or automation system (e.g., by stopping the machine). Therefore, it is particularly important to provide the analysis message along with a diagnostic message as quickly as possible on-site to increase process reliability.

[0024] In a preferred embodiment, the analysis message and / or fieldbus message is not transmitted cyclically from the server to the system, particularly to the coupling module, but only on an event-driven basis. During a preparation phase, it can be configured which events should trigger the transmission of the message. For example, it can be configured that the analysis message and / or fieldbus message should only be transmitted in the event of a diagnostic (or fault) condition. This allows the method to be used even with limited network resources (bandwidth), as fewer transmission resources are required.

[0025] In a further preferred embodiment of the method, the field device generates the fieldbus message from the analysis message, or in other words, the analysis message (from the server) is converted into a fieldbus message (for the controller). This conversion can include protocol conversion and / or format adaptation. The data can be transferred to and / or from the cloud (the cloud-based server), for example, using the MQTT protocol. In the field device, this message can be converted into a PROFINET-specific fieldbus message containing a diagnostic message.

[0026] Another solution involves a computer program with computer program code to carry out all the steps of the procedure described above, when the computer program is executed on a computer. It is also possible for the computer program to be stored on a computer-readable medium.

[0027] Another solution involves a computer program product containing computer program code to execute all the steps of the procedure described above, when the computer program is run on a computer. It is also possible for the computer program to be stored on a computer-readable medium. The computer program product can be, for example, a saved, executable file, possibly with additional components (such as libraries, drivers, etc.), or a computer with the computer program already installed.

[0028] The following section provides a more detailed explanation of the terminology used in this application.

[0029] A diagnostic module is an electronic module that can be distributed across multiple components and is equipped with technical diagnostic functionality, particularly comprehensive methods for predictive maintenance with automatic or semi-automatic instructions for corrective maintenance measures for field devices. Specifically, the diagnostic module, which is implemented locally on devices within the automation system, should be able to access centrally executed calculations. The diagnostic module is configured to perform the diagnostic procedure. The diagnostic module can be configured as a client of a central diagnostic service (running on the server).The calculations performed centrally on the server can be executed by maintenance software that evaluates the transmitted monitoring data and generates an analysis message containing instructions for implementing control and / or diagnostic measures if the maintenance software detects a potential failure of a field device or other components of the automation system at an early stage. Defective components that could soon lead to system shutdown are thus identified independently of regular maintenance schedules and can be replaced before actual damage occurs. Predictive maintenance refers to a maintenance process based on the evaluation of sensor, process, and machine data—referred to here as monitoring data—and uses this data to perform predictive inspections and analyses.Real-time processing of the underlying data enables predictions that form the basis for needs-based maintenance and, consequently, the reduction of downtime. This requires not only the interpretation of sensor data but also a combination of real-time analysis technology and specific databases (e.g., in-memory databases) to achieve sufficiently high access speeds. Predictive maintenance techniques determine the condition of operational equipment to predict when maintenance should be performed. This can lead to cost savings compared to routine or time-dependent preventive maintenance, as tasks are only performed when they are actually necessary. Within the scope of this invention, it is preferred that the analysis be performed in parallel with the operation of the system to avoid downtime.

[0030] According to the invention, monitoring data and / or process data are used to assess the current state of the field device. The monitoring data can be of different types and / or acquired using different methods, such as infrared, acoustics (partial discharge and ultrasound), corona detection, vibration analysis, sound level measurements, etc. The monitoring data is preferably acquired during operation of the field device. The monitoring data relates to the actual state of the system with its field devices and—unlike methods for "preventive maintenance"—not to the average or expected service life in order to predict when maintenance will be required. Alternatively, in addition to the monitoring data, further data can be acquired and / or further data can be calculated and derived from the acquired monitoring data. For example,Based on the collected monitoring data, further processing is initiated to gain new insights into process performance data. This is preferably calculated on the server, for example, in the form of generating collaborative process automation data. For instance, a fault in a higher-level component can be inferred if all or a sufficiently large number of lower-level components fail or exhibit insufficient performance.

[0031] The monitoring data is transmitted to the coupling module, which can be configured as a gateway. This can occur via a push or pull operation. The coupling module then forwards the monitoring data to the cloud-based server. It can also be configured when and / or after the occurrence of configurable events the data should be transmitted to the cloud. Likewise, the receipt (retrieval of the results of the predictive maintenance analysis) of the analysis message can be configured. For example, the diagnostic module can provide a variety of available standard monitoring data, which can be subscribed to by the cloud application, preferably using a publish / subscribe method. The data for transmission can be selected on the cloud server (preferably in a cloud dashboard). Alternatively, the following implementation is conceivable: Programmable or configurable preprocessing runs in the field device.Only aggregated data is then sent to the cloud or server. For example, the travel time of a cylinder can be determined based on the switching points of the cylinder switches. Preferably, only average, maximum, and / or minimum values ​​(AVG / MIN / MAX values) can be determined and sent to the cloud by the field device. This advantageously reduces the data transmission requirements, as only a smaller portion of the data volume needs to be transferred.

[0032] The coupling module functions as a gateway node and features a cloud-based interface (web interface) to the server. This web interface can be implemented, for example, as a web browser. It can be HTTP-based (HTTP - Hypertext Transfer Protocol) or can utilize other (especially stateless, connection-oriented, packet-switched) transport protocols of the TCP / IP reference model, such as FTP (File Transfer Protocol) (TCP - Transmission Control Protocol). The web interface is characterized by its continued activity even during cyclic operation, after the automation system has been commissioned, and its use for exchanging control and regulation data between the coupling module and the cloud-based server. Specifically, the coupling module is configured to transmit control, regulation, and / or diagnostic data (e.g.,...) even during cyclic operation of the system.The coupling module receives the analysis message (in the form of message packets) from a cloud-based server. It receives the analysis message from the server and processes it, or forwards it to the conversion module. The coupling module can also send monitoring and / or process data from the field devices to the server. Furthermore, the coupling module can provide additional functions, in particular aggregating monitoring and / or process data before transmitting it to the server. Specifically, the functionality of the coupling module can be implemented only on selected devices or nodes. For example, it may be intended that only selected field devices are equipped with the gateway functionality.

[0033] A field device is a technical piece of equipment in automation technology that is directly related to a production process, e.g., a CPX-AP. In automation technology, "field" refers to the area outside of control cabinets or control rooms. Field devices can therefore be both actuators (actuators, valves, etc.) and sensors (transmitters) in factory and process automation. Field devices are connected to a control and monitoring system, usually via a fieldbus. They can be equipped with sensors to acquire, generate, and / or aggregate monitoring data so that this data can be used and evaluated for central control, regulation, and further processing. The field device can also be equipped with a user interface, e.g., for visualizing and displaying the monitoring data and / or the analysis result in the form of an analysis message (e.g., a message).(Valve open / closed, pressure, flow rate, temperature) for personnel. The field devices are part of an automation system that may include other devices (e.g., industrial robots).

[0034] A control unit is an electronic module used to control and / or regulate a machine or automation system with a group of field devices and is programmed digitally. It can be, in particular, a programmable logic controller (PLC). In its simplest form, a control unit has inputs, outputs, an operating system (firmware), and an interface through which the user program can be loaded. The user program defines how the outputs are to be switched depending on the inputs. The operating system ensures that the user program always has access to the current state of the sensors. Based on this information, the user program can switch the outputs so that the machine or automation system functions as desired.The control unit is connected to the automation system and its field devices via sensors and actuators. Status indicators are also typically included. Unlike previous systems, the sensors are no longer connected directly to the control unit's inputs, but instead transmit at least some of their monitoring data to the coupling module, representing the state of the machine or field device. This data transmission is not necessarily limited to the coupling module; in most cases, it occurs in addition to the connection to the controller / PLC. Examples of sensors include pushbuttons, light barriers, incremental encoders, limit switches, temperature sensors, level sensors, and so on. The actuators are connected to the control unit's outputs and enable the control of the field devices within the system.Examples of actuators include contactors for switching on electric motors, electric valves for hydraulics or compressed air, and modules for drive controls (motion control, speed control with controlled acceleration or deceleration, stepper motor controls). According to the invention, and advantageously, the control unit itself does not need to have an external network interface for exchanging control data. In particular, the control unit can have only a fieldbus interface. Alternatively, the control unit can also be equipped with additional local (plant-internal) interfaces. This has the advantage that even older types of controllers, which are not yet "cloud-enabled" or equipped with a cloud interface, can be used for a cloud-based diagnostic procedure in order to exchange (especially receive) control data with a cloud-based server during plant operation.

[0035] According to the invention, two different types of interfaces for the automation system are provided: 1. An internal interface for communication between the devices (field devices, control unit, coupling module) within the automation system and 2. An external interface, referred to here as a cloud or web interface.

[0036] A fieldbus is used for the first, internal interface for communication within the automation system. Well-known fieldbus systems can be used, such as PROFIBUS, Interbus, AS-Interface (formerly: ASI), real-time Ethernet systems like PROFINET or EtherCAT, and wireless transmission systems.

[0037] The second, external interface is implemented on a component called a coupling module (also referred to as a gateway). The coupling module can be a separate IoT gateway. Alternatively, the coupling module can be implemented in a dedicated field device. In this case, the field device assumes an additional interface-forming function. The coupling module can be configured to preprocess the monitoring data before it is sent to the cloud. If data is aggregated, syntactically analyzed, compressed, and / or encrypted beforehand, the amount of data that needs to be forwarded to the cloud is reduced to a minimum, which can significantly impact response times and network transmission costs. Furthermore, encryption makes the system more secure. The second, external interface is preferably not implemented on the ECU.

[0038] The conversion module has the functionality to generate a fieldbus message based on the received analysis message (which serves as input for the conversion module). The functionality of the conversion module can only be implemented on a selection of devices. The analysis message comprises server-side calculated diagnostic data. The conversion module can also be configured to send the generated fieldbus message directly to the control unit or to delegate this task to another instance. In a simple embodiment of the invention, the conversion module performs, in particular, a protocol conversion: The analysis message in the HTTP-based format is converted into a fieldbus message in the fieldbus format. In further embodiments, the conversion module performs additional processing steps to generate the fieldbus message containing diagnostic data.For example, a receiver specification can be defined here, i.e., a determination of which devices in the field should receive the fieldbus message. This allows the circle of receivers to be reduced, so that, for example, only those controllers that need to initiate diagnostic and / or fault correction measures receive the fieldbus message.

[0039] "Modified control" refers to the fact that the control system is modified in response to the analysis message and thus to the result of the predictive maintenance algorithm, which was executed on the server based on the monitoring data. This allows individual field devices to be switched off or controlled differently in a timely manner before they fail.

[0040] The analysis message is a data set containing control instructions that are to be implemented on the control unit for modified control. However, the analysis message cannot be directly read and applied on the control unit (since the control unit can only be addressed via the fieldbus), but must first be converted into a fieldbus message. The conversion module serves this purpose. Brief overview of the characters

[0041] The following detailed description of the figures discusses exemplary embodiments, which are not to be understood as limiting, along with their features and further advantages, based on the drawing. This drawing shows: Fig. 1 a non-inventive overview of the diagnostic system comprising a diagnostic module and a cloud-based server; Fig. 2 an embodiment of a field device according to the invention with an integrated conversion module; Fig. 3 a more detailed representation of a diagnostic module with additional components; Fig. 4. A more detailed representation of a server; Fig. 5 components of an automation system, connected via a fieldbus; and Fig. 6. An interaction diagram showing the exchange of messages between the respective components. Detailed description of exemplary implementations using the figures

[0042] The invention serves for the technical monitoring of field devices controlled by a control unit that does not have a web interface (or does not have a web interface). The monitoring is to be carried out using procedures and processes implemented on a cloud server. In particular, predictive maintenance methods are to be performed.

[0043] In Fig. Figure 1 shows a schematic representation of the diagnostic system. On the automation system AA side, it comprises the diagnostic module DM, and on the cloud side, a server S accessible via a web interface. The diagnostic module DM includes a set of field devices FG, such as actuators and sensors, controlled by at least one (local) controller, which can be a programmable logic controller (PLC) and is therefore designated with the reference symbol PLC. The diagnostic module also includes a coupling module, which acts as a gateway to the cloud and is therefore designated with the reference symbol GW. The coupling module is also referred to as gateway GW in the following. The gateway GW implements a web interface WS-GW, which serves to access the cloud-based server S. As shown in Fig. As shown schematically in Figure 1, the programmable logic controller (PLC) does not have internet connectivity, but is only connected to a bus B, which can be configured as PROFINET, for example. The internet connectivity (in Fig. (1, marked with a solid double line) is provided exclusively via the gateway GW. The gateway GW, the field devices FG, and the PLC communicate via a fieldbus B, as will be explained in more detail later in relation to Fig. 5 is described. Fig. Figure 1 shows that the fieldbus B – shown as a dashed line – is a different interface than the web-based interface between the gateway GW and the server S (which may be based on an HTTP or HTTP / S protocol, for example). Since these are different interfaces / protocols, the messages exchanged via them cannot be transmitted unchanged but must be "translated." The PLC controller does not have web connectivity but can nevertheless (indirectly) use web-based services for diagnosing the field devices FG with the architecture according to the invention.

[0044] In the Fig. In the non-inventive embodiment shown in Figure 1, a separate gateway GW is provided, which serves as an intermediary between the server S and the field device FG and / or the programmable logic controller PLC.

[0045] Fig. Figure 2 shows the embodiment according to the invention, in which the gateway GW is not provided as a separate component, but is integrated into one of the field devices FG. At least one of the field devices then has the gateway or coupling functionality (Internet connectivity). In this embodiment, the task of the gateway GW is delegated to at least one field device FG. The task can also be delegated to several field devices FG and thus distributed across them.

[0046] In Fig. Section 3 describes the diagnostic module DM with the gateway GW in more detail. The gateway GW is equipped with a web interface WS-GW for data communication with the cloud-based server S. In particular, an analysis message ant can be received from the cloud-based server S via this interface. The analysis message ant is the result of an analysis algorithm for predictive maintenance, which is executed on the server S. The result, in the form of the analysis message ant, is forwarded via the web interface WS-GW and from there to a conversion module UM. The conversion module UM is configured to transform the received analysis message ant into a fieldbus message fn. This typically requires a series of computational steps. In particular, a protocol conversion must be performed.

[0047] The fieldbus message fn is configured to be sent via the local fieldbus system B to a field device FG and from there to the programmable logic controller (PLC). In response to the received fieldbus message, the PLC can control the respective field devices FG in a modified manner. In an alternative embodiment of the invention, the fieldbus message fn can be sent by the conversion module UM not to the field device FG, but directly to the programmable logic controller (PLC). This is in Fig. 3 is shown with the dashed line.

[0048] Server S is, as in Fig. Figure 4 shows a schematic representation of the device, which is equipped with a web interface WS-S through which it receives and sends data and communicates with the gateway GW of the diagnostic module DM. Furthermore, it has a processor P as a computer-based processing unit (e.g., consisting of several processors) for executing predictive maintenance procedures. For this purpose, the processor P receives the monitoring data md aggregated from several field devices FG. Optionally, additional process data pd can also be received. From this data and possibly further metadata, the processor calculates an analysis result and provides it in the form of the analysis message ant, which, as described above, is used in conjunction with... Fig. The data described in section 3 is transmitted to the diagnostic module DM and its components. The monitoring data md and / or process data pd can be sent to the server cyclically (e.g., at configurable intervals). However, the analysis result, in the form of the analysis message ant, is preferably not sent cyclically (back) to components of the system AA, especially to the gateway GW, but rather event-based, particularly when the analysis or server-side evaluation indicates that a field device or its component requires maintenance. During a preparation phase, configurations can be made to determine the conditions and / or events after which the analysis message ant should be sent to the coupling module GW.

[0049] The programmable logic controller (PLC), the field devices (FG), and the gateway (GW) exchange data via the bus system. As in Fig. As shown in Figure 5, only the gateway (GW) is configured to communicate externally with the internet (www) via appropriate protocols (e.g., IP-based protocols) and thus with the server (S). The programmable logic controller (PLC) does not need any internet connectivity. The functionality of the gateway (GW) can also be implemented in at least one field device (FG).

[0050] Fig. Figure 6 is an interaction diagram for data exchange between the components involved: the programmable logic controller (PLC), a field device (FG) – representing a set of field devices (FG) to be monitored – the gateway (GW) and the server (S).

[0051] In a preliminary step S0, monitoring data (md) is acquired and aggregated on the field devices (FG). A storage device (not shown in the figures) may be provided for this purpose. The collected data is gathered from all field devices (FG) and transmitted as monitoring data (md) to the gateway (GW) in step S1. In step S2, the gateway (GW) sends the monitoring data (md) – optionally enriched with additional data (e.g., metadata, operational data, etc.) – to the server (S). Optionally, the gateway (GW) can be configured to process the monitoring data (md) before transmission, for example, by encrypting it. This enhances the security of the process. In one variant, the monitoring data (md) can also be compressed to reduce the resources required for data transmission to the server (S). After receiving the monitoring data (md), the server (S) can execute the predictive maintenance algorithm to generate the analysis message (ant).In one variant, the predictive maintenance algorithm can be configured to execute only after receiving a trigger signal. This trigger signal can be based on a time-based rule and / or event-based (e.g., after receiving data from a minimum number of monitoring-data-transmitting field devices). In step S4, the analysis message `ant` is transmitted to the gateway `GW`, which in turn forwards it to the conversion module `UM` in step S5. The conversion module `UM` calculates the fieldbus message `fn` from the analysis message `ant` and sends it to the programmable logic controller (PLC) in step S7. The PLC can then, in step S8, control the field devices in a modified manner by implementing the specifications of the predictive maintenance algorithm.

[0052] Finally, it should be noted that the description of the invention and the exemplary embodiments are not to be understood as limiting with regard to a specific physical realization of the invention. All features explained and shown in connection with individual embodiments of the invention can be provided in different combinations in the subject matter of the invention in order to simultaneously realize their advantageous effects.

[0053] The scope of protection of the present invention is defined by the following claims and is not limited by the features explained in the description or shown in the figures.

[0054] It is particularly obvious to a person skilled in the art that the invention can be applied not only to certain field devices, such as the CPX-AP, but also to field devices of other types. Furthermore, the components of the DM dialysis module can be distributed across several physical products.

Claims

[1] Diagnostic module (DM) for the technical diagnosis of field devices (FG) of an automation system (AA), comprising: - To exchange control and / or regulation data between a local control unit (PLC) that has a fieldbus interface and is not configured with the cloud-based server (S); - At least one field device (FG); - A coupling module (GW) integrated into the field device (FG) with: o A web interface (WS-GW) for data communication with a cloud-based server (S) and for receiving an analysis message (ant) from the cloud-based server (S); ◯ A conversion module (UM) for generating a fieldbus message (fn) from the received analysis message (ant) and for sending the fieldbus message (fn) to the control unit (PLC); - A fieldbus (B) for internal communication between the devices of the automation system (AA) and for forwarding the generated fieldbus message (fn) to the control unit (PLC) for controlling the automation system (AA). [2] Diagnostic module (DM) according to claim 1, wherein the local control unit (PLC) is not configured to receive control and / or regulation data during cyclic operation of the automation system (AA). [3] Diagnostic module (DM) according to one of the preceding claims, wherein the control unit (PLC), the at least one field device (FG) and the coupling module (GW) are in data communication via the fieldbus (B). [4] Diagnostic system for the technical diagnosis of field devices (FD) operated in an automation system (AS), comprising: - A diagnostic module (DM) according to claim 1; - A cloud-based server (S) that is connected to the diagnostic module (DM) via the web interface (WS-S). [5] Diagnostic system according to the preceding claim directed to the diagnostic system, wherein the server (S) comprises a web interface (WS-S) and a processor (P), the processor (P) being configured to execute a predictive maintenance algorithm which calculates an analysis message (ant) from monitoring data (md) acquired on the field devices (FG). [6] Method for diagnosing field devices (FD) for operation in an automation system (AS), comprising the following process steps: - Sending (S1) monitoring data (md) from the field devices (FG) to a coupling module (GW) integrated in a field device (FG); - Initiating (S2) a transmission of the monitoring data (md) from the coupling module (GW) to a cloud-based server (S); - Triggering (S3) the execution of a predictive maintenance algorithm on the server (S) based on the received monitoring data (md) to generate an analysis message (ant); - Receiving (S4) the generated analysis message (ant) on the coupling module (GW); - Sending (S5) the analysis message (ant) from the coupling module (GW) to a conversion module (UM); - Generation (S6) of a fieldbus message (fn) from the analysis message (ant) by the implementation module (UM); - Sending (S7) the fieldbus message (fn) to a local control unit (PLC) for controlling the automation system (AA) based on the fieldbus message (fn), whereby the local control unit (PLC) is not configured to exchange control and / or regulation data with the cloud-based server (S). [7] Method according to the preceding method claim, wherein process data (pd) are sent from the field device (FG) in addition to the monitoring data (md) and / or wherein the process data (pd) can be attached to the analysis message (ant) directly or in processed form after the analysis message (ant) has been generated on the server side. [8] A method according to any of the preceding method claims, wherein a field device (FG) from a set of field devices (FG) participates in the method and is uniquely identifiable via an identifier, the identifier being linked to the respective monitoring data (md) and / or process data (pd) so that the server (S) processes the monitoring data (md) in a field device-specific manner and also generates the analysis messages (ant) in a field device-specific manner, so that the analysis message (ant) is linked to the identifier, so that the coupling module (GW) receives the analysis messages (ant) together with the identifier and can then transmit them dedicatedly to the field device (FG) identified by means of the identifier. [9] Method according to the immediately preceding method claim, wherein the analysis message (ant) is directly and locally output, preferably in optical form, after being received on the diagnostic module (DM) and in particular on the field device (FG) assigned by means of the identifier. [10] Method according to any of the preceding method claims, wherein the predictive maintenance algorithm processes historical data and / or reference data in addition to the recorded monitoring data (md) to generate the analysis message (ant). [11] Method according to one of the preceding method claims, wherein the predictive maintenance algorithm serves to calculate a diagnostic message and in particular represents a need to replace a component of the field device (FG) or the field device (FG), wherein the need to replace can in particular be calculated from a number of switching cycles of a cylinder. [12] Method according to any of the preceding method claims 6 to 9, wherein the field device (FG) generates the fieldbus message (fn) from the analysis message (ant) by performing an automatic protocol conversion and / or a format change. [13] Computer program with computer program code for carrying out all process steps of a method according to any of the preceding method claims 6 to 9 and 12, when the computer program is executed on a computer.

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