Field device for checking the quality of a network connection

Description

[0001] The invention relates to a field device for automation technology with a function for checking the quality of a network connection.

[0002] Field devices are already known from the state of the art and are used in industrial plants. They are widely employed in process automation as well as in manufacturing automation. In principle, field devices are defined as all devices that are used close to the process and that provide or process process-relevant information. Thus, field devices are used to acquire and / or influence process variables. Measuring instruments or sensors are used to acquire process variables. These are used, for example, for measuring pressure and temperature, conductivity, flow rate, pH, level, etc., and acquire the corresponding process variables such as pressure, temperature, conductivity, pH value, level, and flow rate. Actuators are used to influence process variables.These include, for example, pumps or valves that can influence the flow of a liquid in a pipe or the fill level in a container. In addition to the aforementioned measuring devices and actuators, field devices also include remote I / Os, radio adapters, and generally any devices located at the field level.

[0003] A large number of such field devices are produced and distributed by the Endress+Hauser Group.

[0004] In modern industrial plants, field devices are typically connected to higher-level units via communication networks such as fieldbuses (Profibus®, Foundation® Fieldbus, HART®, etc.). These higher-level units are usually control systems or automation 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 commissioning of the field devices. The measured values ​​acquired by the field devices, especially sensors, are transmitted via the respective bus system to one (or possibly several) higher-level unit(s). Data transmission from the higher-level unit to the field devices via the bus system is also necessary, particularly for configuring and parameterizing field devices and controlling actuators.

[0005] Mobile operating devices are frequently used to operate field devices (e.g., to configure parameters or retrieve data). These are connected to a field device either via cable (e.g., a service interface) or wirelessly (e.g., via Bluetooth). Examples of operating devices include laptops, mobile devices such as smartphones or tablets, or central asset management stations.

[0006] Various solutions exist on the market for measuring individual parameters that allow conclusions to be drawn about the connection quality of network participants or the status of a network.

[0007] As a first example, let's consider network components from Cisco, which determine a so-called "Network Health Score." This is the percentage of correctly functioning ("healthy") devices on the network relative to the total number of devices. A health index is calculated for each device. If this index is between 8 and 10, a device is considered to be functioning correctly. This "Network Health Score" is recalculated every 5 minutes (see also: https: / / www.cisco.com / c / en / us / td / docs / cloud-systems-management / networkautomation-and-management / dna-center-assurance / 1-3 / b_cisco_dna_assurance_1_3_ug / b_cisco_dna_assurance_1_3_ug_chapter_0101.html#concept_f 5g_rpg_bfb).

[0008] As a second example, a switch from the company Indu-Sol can be mentioned, which enables leakage current monitoring (see https: / / www.indu-sol.com / fileadmin / user_upload / produkte / profinet / infrastrukturkomponenten / Switche / Indu-Sol_PROFINET_Switch_PROmeshP9.pdf for further information).

[0009] Typically, such solutions consider the network as a whole or infrastructure components (e.g., switches). However, from the perspective of a field device, no solutions are known that summarize connection quality in a simple way.

[0010] From EP 3 648 416 A1, an automation device with integrated network analysis is known. From US 9 009 542 B1, an asset health monitoring system is known that assigns a trust indicator to connected computer systems or network devices. From US 2018 / 091392 A1, a system is known that provides a graphical representation of network health information related to a customer account of a provider network.

[0011] The invention is based on the objective of presenting a field device that can automatically make statements about the connection quality with a communication network.

[0012] The problem is solved by a field device of automation technology according to claim 1.

[0013] The field device according to the invention allows for a simple assessment of the connection quality with the communication network in which it is integrated. For this purpose, the field device reads communication information that is recorded and stored by default, depending on the network type or protocol used. Interpreting this communication information, and in particular making a statement about it, sometimes requires in-depth protocol-specific knowledge. However, the field device according to the invention processes this communication information automatically. The result, i.e., the communication status, is easy for service personnel and plant operators to understand, so that no protocol-specific knowledge is required.

[0014] In the context of the field device according to the invention, the communication stack is understood as a conceptual architecture of communication protocols. Visually, the individual protocols are arranged one above the other as consecutively numbered layers of a stack. Each layer uses the layer below it in the protocol stack to fulfill its specific task. During operation, information is automatically collected in this communication stack, depending on the protocol, and stored in a data memory associated with the communication stack.

[0015] A PHY is a term from computer and communications engineering that refers to a special integrated circuit or functional group within a circuit responsible for encoding and decoding data between a purely digital system and a modulated analog system. PHY stands for "physical interface." The term can be found, for example, on the circuit diagrams of Ethernet cards. Fully integrated Ethernet controller chips have a built-in "PHYceiver."

[0016] The network participants include, for example, other field devices, but also control units (e.g. PLCs), infrastructure components (switches, gateways) or industrial PCs.

[0017] Examples of field device types have already been listed in the introductory part of the description.

[0018] According to an advantageous embodiment of the field device according to the invention, it is configured to make the communication status available to one or more of the network participants via a communication interface. The field device can transmit the communication status (depending on the type / protocol of the communication network) independently (either directly to at least one of the communication participants or via broadcast), or upon request from one of the network participants. It can also be provided that the field device has a further communication interface and uses this to transmit the communication status via another communication network, e.g., via a wireless network (Bluetooth, WiFi, etc.).

[0019] According to an advantageous embodiment of the field device according to the invention, the field device has a display unit, wherein the field device is configured to output the communication status via the display unit – alternatively to or additionally to the embodiment described above. The display unit is, for example, a display. However, the term "display unit" can be interpreted broadly, so that a web server for outputting the communication status or a communication interface for retrieving the communication status by operating units can also be understood as a display unit.

[0020] According to an advantageous embodiment of the field device according to the invention, the communication network is an Ethernet-based network, in particular Modbus TCP, PROFINET, EtherNet / IP or OPC UA. It goes without saying that other network types / protocols that provide for the acquisition and generation of communication information as standard features can also be used.

[0021] According to an advantageous embodiment of the field device according to the invention, the communication information includes the following: A status indicating whether a communication connection is established via at least one communication interface, or, if available, via multiple communication interfaces; a number of bytes received from the communication interface; a number of byte reception errors; a number of bytes transmitted from the communication interface.Sent bytes; A number of byte transmission errors; A number of active TCP connections; A number of received TCP frames; A number of TCP frame reception errors; A number of transmitted TCP frame packets; A number of TCP frame transmission errors; A number of available UDP ports; A number of received UDP frame packets; A number of UDP frame packet reception errors; A number of transmitted UDP frame packets; A number of UDP frame packet transmission errors; An Application Relation (AR) status; Information regarding the approximate network load of incoming data or packets; Information regarding the approximate network load of outgoing data or packets.

[0022] This communication information can be divided into protocol-specific communication information and port diagnostic information. Protocol-specific communication information (e.g., TCP- or UDP-related information; network load in the case of PROFINET) is not available for all protocol types, but only for certain protocols. Port diagnostic information is generally available for all protocol types and includes general information about sent / received bytes, the signal level, the signal-to-noise ratio, and is collected, for example, by the PHY.

[0023] This communication information is available as numerical values ​​and may be normalized (e.g., converted into percentages) so that it can be easily processed by the algorithm.

[0024] The invention is explained in more detail with reference to the following figure. It shows Fig. 1: an embodiment of the field device according to the invention, which is integrated into a communication network.

[0025] In Fig. 1 The image shows a field device FG. This device is used, for example, to measure the flow velocity of a fluid medium in a pipeline. However, it could be any other type of field device, as exemplified in the introductory part of the description.

[0026] The field device FG is integrated into a communication network via two connection lines, L1 and L2. These lines form a ring topology. The subsequently calculated communication state KO allows, for example, the determination of whether the ring topology has been broken or whether the network system is functioning correctly.

[0027] Connecting the field device FG to the network requires connecting it to just one of the two lines, L1 or L2. Alternatively, the field device can be configured to be connected to only one of these lines. In this example, it uses the PROFINET protocol. Lines L1 and L2 are connected to the communication interface of the field device FG. Depending on the network type, the field device FG is supplied with the necessary electrical power either via lines L1 and L2 or via a separate power supply (SV).

[0028] Other network participants besides the field device are a higher-level unit (TU), in this case a PLC, which queries measured values ​​from the field device (FG), and a switch (SW), which, as an infrastructure component, connects further segments of the communication network that are not shown.

[0029] During operation, the communication interface of the field device FG continuously collects communication information, which allows for an assessment of the field device FG's connection performance within the communication network. For this purpose, a communication stack and a PHY are assigned to the communication interface, which perform these tasks. At regular intervals, or upon user initiative or query from one of the network participants NT, the operating electronics of the field device FG access the communication stack and the PHY to read the communication information stored there. An algorithm is assigned to the operating electronics that processes the read communication information and calculates a communication state KO.

[0030] The communication state (KO) is calculated using an algorithm. This algorithm applies a mathematical formula to process the individual communication information. There are several ways to do this: 1) The average is calculated across all communication information. All communication information has the same weighting factor. 2) A weighted formula is used, in which individual communication information receives specific weighting factors. For example, UDP-specific communication information receives high weighting factors because it concerns cyclical telegrams and is therefore important to ensure a correctly functioning process.

[0031] In addition to or as an alternative to 1) or 2), threshold values ​​can be defined for individual communication information. If these values ​​are exceeded or fallen below, depending on the type, the worst possible status is selected, regardless of the values ​​of the other communication information. An example is the communication information "Status of whether a communication connection is established via the communication interface or not." If no communication information is established, the worst possible status is selected by default.

[0032] 3.) The algorithm is based on an AI model, such as a deep learning model or a neural network, which is trained beforehand using training data to recognize the three states Z1, Z2, Z3 and can sometimes detect subtle nuances in the communication information in order to identify the correct state Z1, Z2, Z3. The algorithm can include a feedback function: If, for example, the worst possible state Z3 is calculated, but the connection works perfectly, this can be communicated to the algorithm as feedback. The algorithm learns from these experiences and improves over time.

[0033] The calculated communication state KO is stored as a numerical value. Depending on the magnitude of the communication state KO, it is classified into one of three states: Z1, Z2, or Z3. The threshold values ​​at which each state is reached are stored by default in the field device FG but can be edited by a user. State Z1 is the best possible case and means "Communication OK - Good." State Z2 means "Communication impaired - Maintenance required." State Z3 is the worst possible state and means "Communication disrupted - Maintenance demanded."

[0034] The communication status AI, or the respective status Z1, Z2, Z3, can be read via the display unit AE of the field device FG. For example, a special menu entry is available through which the communication status can be selected and read. It may also be possible to make the communication status KO available to the network participants ÜE, SW via a communication interface, or to make it available to other devices, such as operator panels using the "SmartBlue" app developed by the applicant, via another communication interface, e.g., a radio interface.

[0035] The communication state (KO) is calculated using an algorithm. This algorithm applies a mathematical formula to process the individual communication information. There are several ways to do this: 1) The average is calculated across all communication information. All communication information has the same weighting factor. 2) A weighted formula is used, in which individual communication information receives specific weighting factors. For example, UDP-specific communication information receives high weighting factors because it concerns cyclical telegrams and is therefore important to ensure a correctly functioning process.

[0036] In addition to or as an alternative to 1) or 2), threshold values ​​can be defined for individual communication information. If these values ​​are exceeded or fallen below, depending on the type, the worst possible status is selected, regardless of the values ​​of the other communication information. An example is the communication information "Status of whether a communication connection is established via the communication interface or not." If no communication information is established, the worst possible status is selected by default.

[0037] 3.) The algorithm is based on an AI model, such as a deep learning model or a neural network, which is trained beforehand using training data to recognize the three states Z1, Z2, Z3 and can sometimes detect subtle nuances in the communication information in order to identify the correct state Z1, Z2, Z3. The algorithm can include a feedback function: If, for example, the worst possible state Z3 is calculated, but the connection works perfectly, this can be communicated to the algorithm as feedback. The algorithm learns from these experiences and improves over time.

[0038] The calculated communication state KO is stored as a numerical value. Depending on the magnitude of the communication state KO, it is classified into one of three states: Z1, Z2, or Z3. The threshold values ​​at which each state is reached are stored by default in the field device FG but can be edited by a user. State Z1 is the best possible case and means "Communication OK - Good." State Z2 means "Communication impaired - Maintenance required." State Z3 is the worst possible state and means "Communication disrupted - Maintenance demanded."

[0039] The communication status AI, or the respective status Z1, Z2, Z3, can be read via the display unit AE of the field device FG. For example, a special menu entry is available through which the communication status can be selected and read. It may also be possible to make the communication status KO available to the network participants ÜE, SW via a communication interface, or to make it available to other devices, such as operator panels using the "SmartBlue" app developed by the applicant, via another communication interface, e.g., a radio interface. Reference symbol list

[0040] AE Display unit EI External influence FG Field device KO Communication state L1, L2 Connection lines SV Power supply SWS Switch, network participant ÜE Superior unit, network participant Z1, Z2, Z3 States

Claims

1. Field device (FD) of automation technology having a function for checking the quality of a network connection, wherein the field device (FD) comprises operating electronics and at least one communication interface for connection to a communication network with one or more network participants (SW, UE) and for establishing a communication connection, wherein a communication stack and a PHY are assigned to the communication interface, wherein the communication stack and the PHY are designed to continuously collect and store a plurality of communication information relating to the communication connection, wherein the operating electronics are designed to read the communication information from the communication stack and from the PHY and to calculate the communication information by means of an algorithm, and, based on the calculation result, to classify a communication state (CS), wherein the communication information comprises port diagnostic information, said port diagnostic information including general information relating to transmitted and received bytes, signal level, and signal-to-noise ratio, wherein the communication information is present as numerical values, wherein the communication state (CS) is present as a numerical value and, depending on the magnitude of the communication state (CS), is classified into one of three states (S1, S2, S3), and wherein threshold values defining when a respective state (S1, S2, S3) is reached are stored in the field device (FD).

2. Field device (FD) according to claim 1, wherein the field device (FD) is designed to provide the communication state (CS) via the communication interface to one or more of the network participants (SW, UE).

3. Field device (FD) according to claim 1 or 2, wherein the field device (FD) comprises a display unit (DU) and wherein the field device (FD) is designed to output the communication state (CS) via the display unit (DU).

4. Field device (FD) according to at least one of the preceding claims, wherein the communication network is an Ethernet-based network, in particular Modbus TCP, PROFINET, or EtherNet / IP.

5. Field device (FD) according to at least one of the preceding claims, wherein the communication information comprises the following: • a status indicating whether a communication connection is established via the communication interface or not; • a status indicating whether a ring connection is established; • a number of bytes received by the communication interface; • a number of byte reception errors; • a number of bytes transmitted or sent by the communication interface; • a number of byte transmission errors; • a number of active TCP connections; • a number of received TCP frames; • a number of TCP frame reception errors; • a number of transmitted TCP frames; • a number of TCP frame transmission errors; • a number of available UDP ports; • a number of received UDP frames; • a number of UDP frame reception errors; • a number of transmitted UDP frames; • a number of UDP frame transmission errors; • an application relation status; • information regarding the approximate network load of incoming data or packets; and / or • information regarding the approximate network load of outgoing data or packets.