WO2023117319A1

WO2023117319A1 - Method for reducing the amount of data transmitted between an automation field device and a cloud

Info

Publication number: WO2023117319A1
Application number: PCT/EP2022/083500
Authority: WO
Inventors: Peter WAZINSKI; Sushil Siddesh; Hermann Spohn
Original assignee: Endress+Hauser Process Solutions Ag
Priority date: 2021-12-22
Filing date: 2022-11-28
Publication date: 2023-06-29
Also published as: DE102021134324A1

Abstract

The invention relates to a method for reducing the amount of data transmitted between an automation field device (FG1, FG2, FG3) and a cloud (CL), the method comprising: - an aggregator component (AG) of the cloud (CL) creating a configuration file (KD), which configuration file (KD) contains a list of precisely those process variables (V1, V2,..., Vn) which respective cloud applications (CA1, CA2, CA3) of the cloud (CL) need for gathering or further processing; - transmitting the configuration file (KD) to the field device (FG1, FG2, FG3); - the field device (FG1, FG2, FG3) capturing current measurement data for all the process variables (V1, V2,..., Vn) contained in the list of the configuration file (KD); - the field device (FG1, FG2, FG3) collectively transmitting the captured measurement data to a distributor component (VK) of the cloud (CL); - the distributor component (VK) distributing the data to the respective cloud applications (CA1, CA2, CA3) which need the respective measurement data, or the distributor component (VK) providing the measurement data and the respective cloud applications (CA1, CA2, CA3) which need the respective measurement data retrieving the measurement data; and - repeating the steps of capturing the current measurement data and collectively transmitting the captured measurement data and distributing the measurement data at predefined time intervals.

Description

Method for reducing the amount of data transmitted between a field device in automation technology and a cloud

The invention relates to a method for reducing the amount of data transmitted between a field device used in automation technology and a cloud, with the field device acquiring measurement data for a large number of process variables, with the field device having a communication unit, with the field device being able to be connected to the cloud using the communication unit, with the cloud has an aggregator component and a distributor component, and a large number of cloud applications run on the cloud, which cloud applications each collect and/or further process the measurement data of the field device from at least one of the process variables.

Field devices that are used in industrial plants are already known from the prior art. Field devices are often used in process automation technology as well as in production automation technology. In principle, all devices that are used close to the process and that supply or process process-relevant information are referred to as field devices. Thus, 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 pressure, temperature, conductivity, pH value, level, flow rate, etc. Actuators are used to influence process variables. These are, 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 measuring devices and actuators mentioned above, field devices also include remote I/Os, radio adapters or devices in general that are arranged at the field level.

A large number of such field devices are produced and sold by the Endress+Hauser Group. In modern industrial plants, field devices are usually connected to higher-level units via communication networks such as fieldbuses (Profibus®, Foundation® Fieldbus, HART®, etc.). Normally, the higher-level units are 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 measurement data recorded by the field devices, in particular by sensors, are transmitted via the respective bus system to one (or optionally several) higher-level unit(s). In addition, data transmission from the higher-level unit via the bus system to the field devices is also necessary, in particular for configuring and parameterizing field devices and for controlling actuators.

In the course of Industry 4.0 or lloT (“Industrial Internet of Things”), the data generated by the field devices is often collected directly from the field using so-called data conversion units, which are referred to as “edge devices” or “cloud gateways”, for example and automatically transmitted to a central cloud-enabled database (also referred to simply as “cloud”) on which an application is located. This application, which offers, among other things, functions for the visualization and further processing of the data stored in the database, can be accessed by a user via the Internet.

Alternatively, the field devices transmit their data independently to the cloud. You need electrical energy for this, in addition to the electrical energy required for your measurement operation. The devices can be connected to the power grid for this purpose, for example if they are operated in a system. Alternatively, they can also be equipped with a battery without being connected to the mains, for example to transmit data from a hard-to-reach place - for example from a groundwater flow in a forest.

The battery power must be designed in such a way that it supplies the field device with electrical energy for several years, for example up to 10 years. Even a small one Daily power consumption adds up to a significant amount of energy over the years and can significantly reduce battery life.

Today, the cloud sequentially queries the measurement data of the required process variables from the field device for each individual cloud application. The field device responds separately to each of the requests. The amount of time and amount of data required for the transmission of the requests from the cloud and the respective responses from the field device is high.

Proceeding from this problem, the object of the invention is to reduce the amount of data transmitted between a cloud and a field device communicating with the cloud.

The object is achieved by a method for reducing the amount of data transmitted between a field device used in automation technology and a cloud, with the field device acquiring measurement data for a large number of process variables, with the field device having a communication unit, with the field device being able to be connected to the cloud using the communication unit , wherein the cloud has an aggregator component and a distributor component, and wherein a large number of cloud applications run on the cloud, which cloud applications each collect and/or further process the measurement data of the field device from at least one of the process variables, comprising:

- Creation of a configuration file by the aggregator component of the cloud, which configuration file contains a list of exactly those process variables which the respective cloud applications need for collecting or further processing;

- Transmission of the configuration file to the field device;

- Capture current metrics for all of the in the list of

process variables contained in the configuration file by the field device;

- Collective transmission of the recorded measurement data to the distributor component of the cloud by the field device;

- Distribution of the measurement data by the distribution component to the respective cloud applications that require the respective measurement data, or Provision of the measurement data by the distributor component and retrieval of the measurement data by the respective cloud applications that require the respective measurement data; and

- Repeating the steps of acquiring the current measurement data and the collective transmission of the acquired measurement data and the distribution of the data at predetermined time intervals.

The essence of the invention is that the field device independently transmits all measurement data required by the cloud applications in a single transmission step. As a result, the operating time during which the field device transmits data is reduced, with the result that the energy requirement of the field device is also correspondingly reduced.

In the case of field devices that are battery-operated and communicate with the cloud via a mobile radio modem or special network protocols such as LoRaWAN, the method according to the invention is particularly advantageous since the service life of the battery is increased in this way.

Examples of such field devices, which are mentioned in connection with the method according to the invention, have already been listed in the introductory part of the description. However, the method is also advantageous for mains-operated field devices that are installed in a system and communicate indirectly with the cloud via an edge device, since the amount of transmission between edge device and field device is reduced.

According to an advantageous development of the method according to the invention, it is provided that the field device also acquires or generates measurement data and/or status information for a large number of defined process variables, which are transmitted separately to the cloud at the predetermined time periods. These defined process variables are often stored (hardcoded) in the field device by default, for example typical process variables such as volume flow or the temperature of the process medium. It is intended to transmit this measurement data and/or status information to the cloud first, before the measurement data for all of the process variables contained in the list of the configuration file are transmitted to the cloud.

In an advantageous embodiment of the method according to the invention, it is provided that the communication unit is operated in an idle state by default, with the communication unit being used to transmit the measurement data or

Status information for the plurality of defined process variables and for the collected transmission of the acquired measurement data changes to an active mode, and the communication unit changes back to the idle mode after the transmission and the collected transmission. The field device is therefore designed in such a way that it continuously acquires the measurement data for the respective process variables, but only switches on its communication unit at specified time intervals or periodically. Alternatively, the measuring operation of the field device is also idle when the communication unit is not switched on.

The communication unit is switched on in one of the predetermined time periods or periodically. The measurement data and/or the status information of the defined process variables are then first transmitted on the basis of the configuration file. The measurement data for all of the process variables contained in the list of the configuration file are then transmitted. The communication unit then switches itself off again.

According to an advantageous embodiment of the method according to the invention, it is provided that the cloud transmits the configuration file for the first time as a response from the cloud to the transmission of the measurement data or status information for the large number of defined process variables to the field device. The measurement data or

Status information for the large number of defined process variables is thus used as a trigger signal for the cloud. The cloud thus knows that the communication unit is currently in switched-on mode and can therefore transmit the configuration file to the field device. An advantageous embodiment of the method according to the invention provides that the aggregator component transmits an updated configuration file to the field device in the event that measurement data from process variables not previously included in the list are required by the corresponding cloud applications, or if measurement data from one or more process variables contained in the list are no longer required by the corresponding cloud applications.

Advantageously, the updated configuration file is sent to the field device immediately after the transmission of the measurement data or status information for the large number of defined process variables or after the transmission of the measurement data for all of the process variables contained in the list of the configuration file, since the communication unit of the field device is at this point in time still in on mode. It can also be provided that a short "waiting time" is programmed into the field device, so that after the measurement data for all of the process variables contained in the list of the configuration file have been sent, the field device leaves the communication unit switched on for a predetermined period of time before it is switched off to to be able to receive any updated configuration file from the cloud.

The invention is explained in more detail with reference to the figure below. It shows

Fig. 1: a schematic overview of a structure in which context the method according to the invention is applied;

2 shows an example method for transmitting data from a field device to the cloud, as is known from the prior art;

3 shows a schematic sequence of the exemplary method known from the prior art;

4: an exemplary embodiment of the method according to the invention; and

5: a schematic sequence of the method according to the invention. 1 shows an example scenario in which the method according to the invention is applied. Three field devices FG1, FG2, FG3 are shown, which carry out different tasks.

Field device FG1 is a radar-based level gauge that measures the level of a medium in a tank. The field device has a battery and a communication unit for connection to a Cloud CL. The field device FG2 is an electromagnetic flow meter which is connected to a water pipe outdoors and which is connected to a communication unit which establishes a communication link with the Cloud CL. The field device FG3 is a Coriolis flow meter that is used in a process plant A. The field device FG3 is primarily connected to a fieldbus to which an edge device ED is connected. The field device FG3 is connected to the cloud CL via the edge device ED.

Each of the field devices FG1, FG2, FG3 thus takes on different tasks and is connected to the cloud CL in different ways. The field device types mentioned in FIG. 1, their number and their applications are to be regarded as purely exemplary. In principle, almost any number of field device types that are capable of transmitting data to the cloud CL can be used in the method according to the invention.

The Cloud CL is a database or server that can be accessed via the Internet. A large number of cloud applications CA1, CA2, CA3 are executed on the cloud CL. The cloud applications CA1, CA2, CA3 are used to visualize, further process and/or prepare data from the field devices FG1, FG2, FG3. Application examples for such cloud applications CA1, CA2, CA3 are, for example, asset management (cloud application CA1), device monitoring (cloud application CA2) and predictive maintenance (cloud application CA3).

In methods known today from the prior art, the data from the field devices FG1, FG2, FG3 reach the cloud CL as follows: 2 shows an overview of an example method in which the field device FG2 transmits data to the cloud. 3 shows the schematic sequence of the exemplary method.

A field device FG2 in the form of a flow meter typically contains more than 1000 variables that can be transmitted to the cloud CL. However, depending on the industry, application and customer, only some of these parameters need to be processed regularly in the Cloud CL. A small set of standard parameters (i.e. typical process variables such as volume flow and medium temperature) or predetermined variables is always periodically sent to the cloud. The configuration for these parameters can be hard-coded at production time so that the field device FG2 periodically sends these variables to the Cloud CL.

At a point in time before t1, the field device FG2 or its communication unit is in a sleep mode. At time t1, which marks the beginning of the periodically repeated time period, the field device FG2 or its communication unit is switched to an active mode.

In a method step S1, the field device FG2 transmits the current measurement data of the predetermined variables, and optionally further data such as status values, to the cloud CL, which the cloud receives at a point in time t2.

Provision is made on the cloud CL for each of the cloud applications CA1, CA2, CA3 to require current measurement data from further process variables V1, V2, . . . , Vn. Such other process variables V1, V2, ..., Vn, in particular scenario-specific parameters, z. B. non-user visible state variables for predictive maintenance applications must be manually configured in the cloud at uptime CL. The cloud sends on demand, i. H. at regular intervals, a request for these process variables V1, V2, ..., Vn to the field device FG. The device must process the variable list for each request and respond with the desired variable values.

In a method step S2, the cloud CL thus sends a request AF to the field device FG2 at a point in time t3. The request AF concerns the cloud application CA1 , which requires current measurement data of the process variables V1 and V2. The field device FG2 then determines the current measurement data of the process variables V1 and V2 at time t4, or reads the current measurement data of the process variables V1 and V2 from a memory. At time t5, the field device FG2 transmits the measurement data of the process variables V1 and V2 in a response AT to the cloud, which receives them at a time t6.

In a method step S4, the cloud CL then sends a request AF to the field device FG2 at a point in time t7. The query AF relates to the cloud application CA2, which requires current measurement data for the process variables V2 and V3. The field device FG2 then determines the current measurement data of the process variables V2 and V4 at time t8, or reads out the current measurement data of the process variables V2 and V3 from a memory. At time t9, the field device FG2 transmits the measurement data of the process variables V2 and V3 to the cloud, which receives them at a time t10.

This process can be repeated as desired depending on the number and requirements of the cloud applications FG1, FG2, FG3. For each request, the field device FG collects and determines the measurement data of the measurement variables mentioned in the query, regardless of whether they have already been collected in a previous request and transmitted to the cloud.

The field device FG or its communication unit remains in the active mode for the entire period t1 to t9 and only switches back to the sleep mode after all requests AF have been processed, until it is woken up again at the beginning of a new cycle. As a result, it has a high energy requirement.

The amount of data to be transmitted for each field device FG1, FG2, FG3, and thus their respective energy requirement, is reduced by means of the method according to the invention (see FIG. 3).

For this purpose, the cloud CL has an aggregator component AK. The aggregator component AK ascertains from each of the cloud applications CA1, CA2, CA3 those process variables which V1, V2, Vn require the corresponding cloud applications and writes them in a list. It is intended that multiple entries will be combined into one entry. In the present case, the list therefore contains the process variables V1, V2 and V3, since the cloud application CA1 requires the process variables V1, V2 and the cloud application CA2 requires the process variables V2, V3.

The list is packed in a configuration file KD. The aggregator component AK of the cloud CD transmits the configuration file KD to the field device FG2, which then stores it. The transmission of the configuration file KD advantageously takes place as a response from the cloud CL to the measurement data of the predetermined process variables transmitted by the field device FG, or its status information.

The field device FG2 now transmits data DT to the cloud CL for each cycle in a predetermined scheme (see FIG. 4):

At a point in time t1', the field device FG, or its configuration unit, changes from the sleep mode to the active mode and transmits the current measurement data of the predetermined process variables to the cloud CL in a method step t1'.

The field device FG2 then reads the configuration file KD and, according to the list contained in the configuration file, determines the current measurement data for the process variables V1, V2, V3 at time t2', or reads the current measurement data for the process variables V1, V2, V3 from the memory. The field device FG2 transmits this data DT to the cloud CL in method step S2'.

The field device FG2 then switches back to the sleep mode. The operating time of the field device FG2 or of its communication unit is drastically reduced compared to the known method described above. This increases the battery life. At time t3′ the measurement data of the predetermined process variables, or the status information, reach the cloud CL. At time t4′ the measurement data of the process variables V1, V2, V3 reach the cloud CL. A distributor component VK of the cloud CL analyzes the measurement data and forwards them to the respective cloud applications CA1, CA2, CA3 in accordance with the requirements. Alternatively, the distributor component provides the measurement data so that the respective cloud applications CA1, CA2, CA3 can collect the measurement data required, for example in the sense of an event-driven architecture using a publish-subscribe pattern.

Is an update of the configuration file KD provided, for example. If a new cloud application is available, if further process variables V1, V2, ..., Vn are of interest for one or more of the cloud applications CA1, CA2, CA3 or if one of the previously required process variables V1, V2, V3 are no longer required, the aggregator component AK creates an updated configuration file KD. Provision is made here for the updated configuration file KD to be transmitted to the field device FG when the cloud CL has received the measurement data for the process variables V1, V2, V3. In this case, the field device FG2 preferably waits until a point in time t5>t4 before it switches back to the sleep mode.

Reference List

1), 2), ... , 7) process steps (prior art)

1)'> 2)' Process steps

AF request from the cloud

AG Aggregator Component

ON plant

AT Response of the field device

CA1 , CA2, CA3 Cloud Applications

CL cloud

Data regularly transmitted to DT

ED Edge Device

FG1 , FG2, FG3 field devices

KD configuration file t1, t2, t9, times (prior art) t1', t4' times

V1 , V2, Vn process variables

VK distribution component

Claims

Claims Method for reducing the amount of data transmitted between a field device (FG1, FG2, FG3) of automation technology and a cloud (CL), the field device (FG1, FG2, FG3) acquiring measurement data for a large number of process variables (V1, V2, Vn), wherein the field device (FG1, FG2, FG3) has a communication unit, wherein the field device (FG1, FG2, FG3) can be connected to the cloud (CL) by means of the communication unit, the cloud (CL) having an aggregator component (AG) and a Has distributor component (VK), and wherein on the cloud (CL) a variety of cloud applications (CA1, CA2, CA3) run, which cloud applications (CA1, CA2, CA3) respectively the measurement data of the field device (FG1, FG2, FG3) collect and/or further process at least one of the process variables (V1, V2, ..., Vn), comprising:

- Creation of a configuration file (KD) by the aggregator component (AG) of the cloud (CL), which configuration file (KD) contains a list of precisely those process variables (V1, V2, ..., Vn) which the respective cloud applications (CA1 , CA2, CA3) for collecting or further processing;

- Transmission of the configuration file (KD) to the field device (FG1, FG2, FG3);

- Acquiring current measurement data for all of the process variables (V1, V2, ..., Vn) contained in the list of the configuration file (KD) by the field device (FG1, FG2, FG3);

- Collective transmission of the recorded measurement data to the distributor component (VK) of the cloud (CL) by the field device (FG1, FG2, FG3);

- Distribution of the measurement data by the distributor component (VK) to the respective cloud applications (CA1, CA2, CA3) that require the respective measurement data, or provision of the measurement data by the distributor component (VK) and collection of the measurement data by the respective cloud applications (CA1, CA2, CA3), which require the respective measurement data; and - Repeating the steps of acquiring the current measurement data and the collective transmission of the acquired measurement data and the distribution of the measurement data at predetermined time intervals.

2. The method according to claim 1, wherein the field device (FG1, FG2, FG3) additionally acquires or generates measurement data and/or status information for a large number of defined process variables, which are transmitted separately to the cloud (CL) at the predetermined time periods.

3. The method according to claim 2, wherein the communication unit is operated by default in an idle state, wherein the communication unit changes to an active mode for transmitting the measurement data or status information for the plurality of specified process variables and for the collective transmission of the measured data recorded, and wherein the communication unit goes back to sleep mode after submitting and collecting submitting.

4. The method according to claim 3, wherein the cloud (CL) the configuration file (KD) for the first time as a response from the cloud (CL) to the transmission of the measurement data or status information for the plurality of specified process variables to the field device (FG1, FG2, FG3) transmitted.

5. The method according to at least one of the preceding claims, wherein the aggregator component (AG) transmits an updated configuration file to the field device (FG1, FG2, FG3) in the event that measurement data from process variables not previously included in the list from the corresponding cloud applications (CA1, CA2, CA3) are required, or if measurement data from one or more process variables (V1, V2, ..., Vn) contained in the list are no longer required by the corresponding cloud applications (CA1, CA2, CA3). become.