DE102015107478A1 - Sensor network and procedures for its operation - Google Patents

Abstract

The object of the invention is to reduce the manual configuration effort of a sensor network. This object is achieved in that the sensor (1) is able to send messages according to a publisher-subscriber model in the network (2), wherein it the corresponding topic data ("Topic") of an RFID reader (3) via receives an internal RFID transponder (13) and receives the measured values via a measuring device (14) and adds as content.

Description

The invention is based on a device for operating a sensor network according to the preamble of independent claim 1.

The invention is further based on a method for operating a sensor network according to the preamble of independent claim 8.

Such sensor networks are needed to communicate measurement data.

State of the art

Sensor networks are known to the person skilled in the art and are currently being described, for example, in the Wikipedia article "Sensor Network". http://de.wikipedia.org/wiki/Sensornetz A sensor network (wireless sensor network) is a computer network of sensor nodes, tiny ("speckled") to relatively large ("shoebox") radio-communicating computers operating either in an infrastructure-based (base station) or in-frame work together with a self-organizing ad-hoc network to query their environment using sensors and relay the information.

The publication DE 10 2006 018 174 A1 describes a measured value acquisition device for detecting physical quantities of a technical process in a process plant, for converting the physical variable into an adequate electrical variable and outputting it to a communication medium. For the flexible detection of a plurality of measurement signals with the least possible installation effort, it is proposed to physically separate the functional group for measured value acquisition and the function group for measured value processing and connect them logically via a wireless communication link to connect the functional group for measured value processing via a conductor loop to a higher-level device. in which the power supply and the transmission of the measurement information via the same pair of wires, and to arrange the function group for data acquisition directly at the measuring point and locally to provide energy.

The publication US20120057581A1 discloses a system and method for operating a sensor node, particularly in an RFID (Radio Frequency Identification Device) environment and associated gateway system.

A disadvantage of the prior art is that the configuration of a sensor network usually takes place via one or more configuration protocols, via a web interface and / or via a change of a program code, and is therefore associated with considerable manual effort.

task

The object of the invention is to reduce this configuration effort.

The object is achieved in a first aspect with a device of the type mentioned by the features of the characterizing part of independent claim 1.

In a second aspect, the object is achieved by a method of the type mentioned by the features of the characterizing part of independent claim 8.

Advantageous embodiments of the invention are specified in the subclaims.

The invention serves the distribution of information, e.g. certain metrics to control over the network.

An advantage of the invention is that the required manual configuration effort is at least significantly reduced.

An additional advantage is that a software update for the microprocessors e.g. multiple sensors can be performed with little manual effort, since the said microprocessors their respective e.g. Site-specific and / or function-specific theme data can be loaded again from the particular writable data memory of the RFID transponder chip after such an update.

Another advantage is that the sensor can be de-energized during its configuration.

For example, current sensors supplied via a so-called "Energy Harvester", i. ie electrical energy from a mechanical change / movement / vibration, etc., complete, e.g. To be potted with a plastic, since they get along without a connector.

In particular, such a sensor can also be configured in the stationary state and thereby manage without wired interfaces.

It is particularly advantageous that the sensor can automatically identify itself in the network and, at least on the Application level, no assignment in the form of an IP address and / or a location over the network must be made.

Configuration information can thus be easily obtained from a mobile terminal, e.g. a tablet or a smart phone, which in this case, e.g. with an additional device, the function of an RFID reader takes over, are transmitted to the sensor.

In a preferred embodiment, an information transmission between the sensor and the network can take place without contact and in particular also during a movement of the sensor.

It is particularly advantageous if the network is constructed according to a so-called "publisher-subscriber model" and in particular according to the MQTT ("Message Queue Telemetry Transport") standard, because such a network is a topic-specific processing of the respective information, ie For example, a topic-specific control and / or selection of specific messages allows. Thus, a so-called "publisher", which is designed for example as a current sensor and can represent a client in the network, publish news about a so-called "message broker" under a certain topic. This message broker can be a dedicated device. However, it can also be a device that already fulfills another function in the network, for example a further such a sensor, which therefore also assumes that of such a message broker in addition to its actual function. It can also be, for example, a server. The message broker allows the sensor to publish messages according to the publisher-subscriber model under a specific topic. The topic for the messages to be sent by him can be interrogated by means of his microprocessor, in particular from the writeable memory of his RFID transponder, the RFID transponder containing the data containing this topic beforehand from an RFID reader, in particular from a stationary RFID reader, had received. The topic can already be present in the RFID reader in a publisher-subscriber-network-compatible format, ie as a so-called "topic", and can also be transmitted in this format to the RFID transponder. A so-called "subscriber", for example a network PC, beacon or other current sensor, or any other client who has subscribed to this topic or topic, thus receives the message formed on that topic and can retrieve its content, e.g. evaluate a corresponding measurement or any other content.

A network participant can simultaneously fulfill both the function of a publisher and that of a subscriber in the network.

In a preferred embodiment, the message broker may be formed by the server. The sensors are preferably publishers. This is particularly advantageous because messages relevant to the message broker can thus be transmitted between the sensors and other clients of the network independently of their addressing and the physical structure of the network, without requiring a central configuration. In particular, at least one of the sensors may be a publisher. This is particularly advantageous because the sensor can thus publish measured values determined by it.

In a preferred embodiment, the sensor is a current sensor. However, the described situation also applies to other, in particular electrically operated, sensors, for example for temperature, pressure, brightness, humidity, smoke or any other type of sensors. For example, the current sensor is used to measure the current passing through a particular bus bar and still serving a particular purpose. In the area of this busbar, for example, a permanently installed RFID reader can be located. In a preferred embodiment, however, a mobile RFID reader can be used which, for example, by a user, in each case in the area of the respective sensor is brought. The RFID reader may already have data that includes the location and / or function of the current sensor / busbar, or they may be entered by the user into the RFID reader at short notice. This data, which is advantageously topic data, is transmitted by the RFID reader to the RFID transponder of the current sensor. This data is then stored in the writable memory of the RFID chip of the RFID transponder. Therefore, it is sufficient to boot the current sensor only now. The microprocessor of the current sensor now requests the said data from the RFID chip of the RFID transponder. These data are then transmitted from the RFID transponder to the microprocessor. Thus, the microprocessor of the current sensor receives the information about the location and / or the function of the relevant busbar / the current sensor. He can use this information as a so-called "topic", i. as a topic for messages in a publisher-subscriber format, especially the MQTT format.

For cost reasons, it is particularly advantageous to use a mobile RFID reader, and to provide him successively several current sensors with such theme data.

With such topic data, the microprocessor is able to create messages with a corresponding topic according to a program stored in its memory: As content of these messages, the current sensor can continue to use the currently measured values for the current intensity, eg in the form of a measure.

In order to be able to send such a message over the network, the sensor requires its own IP ("Internet Protocol") address.

For this purpose, in a preferred embodiment, the current sensor may have a so-called "IPV6 address", which, as is known to the person skilled in the art, can be regarded globally as unique by its size.

In another embodiment, it may receive an IP address from a DHCP (Dynamic Configuration Host Protocol) server which is intended to allocate such IP addresses and to transmit them to clients, in this case to the sensor. Such an IP address may be, for example, a so-called "IPV4" address whose address space is significantly lower than that of the IPV6 address.

The current sensor then uses its IP address to request a message broker to the network. A message broker, or any other network participant, that stores the IP of a message broker, i. a broker IP address, transmits this information, i. this broker IP address to the current sensor. If several such response messages arrive, the current sensor can select one of them according to a predetermined criterion, e.g. he can use the broker IP address of the first incoming message.

By means of this broker IP address, the current sensor can now publish its messages via the corresponding message broker. The message can then be stored in the message broker and each subscriber who has subscribed to the corresponding topic, delivered and / or queried by him.

Furthermore, it is advantageous if further network subscribers, e.g. Further power or other sensors, signal lights, network PCs or sensors are provided as so-called "Subscriber" and also each have a microprocessor and a data memory in which a software program is stored, which is suitable, in particular via the microprocessor, a message receive from the network, because the network participants in this way, the relevant messages for them, in particular according to a particular topic / topic select. In this case, the data memory of the respective subscriber can be part of the associated microprocessor.

In a preferred embodiment, the message broker knows the topics of the subscribers as well as their IP addresses in a lower layer of the network. Thus, only those subscribers receive a particular message over the network if their topic matches their subscription. This has the advantage of avoiding unwanted network traffic. Depending on the extent of the network, i. In particular, the number of clients, in particular the subscriber, while the traffic is advantageously significantly reduced. Conversely, much larger networks are possible with the same data throughput. Nevertheless, the network is built up in a higher layer according to the "publisher-subscriber model" because it behaves accordingly in programming and use. In particular, in the OSI (Open Systems Interconnection) model, a network layer, e.g. Ethernet or WLAN or similar, build the mentioned IP layer as a network layer. A TCP layer can be used as the transport layer on top of this IP layer, which is then used by the publisher subscriber model as an application. In particular, the publisher subscriber model may be constructed according to the MQTT protocol.

embodiment

An embodiment of the invention is illustrated in the drawings and will be explained in more detail below. Show it:

1 a schematic representation of a sensor network;

2 a flow chart for network construction and information transfer.

The figures contain partially simplified, schematic representations. In part, identical reference numerals are used for the same but possibly not identical elements. Different views of the same elements could be scaled differently.

The 1 shows a sensor network comprising three current sensors 1 . 1 . 1 , which are the same structure, but for clarity, only a current sensor 1 is shown explicitly with its components, namely with a microprocessor 11 that with a network interface 12 and an RFID transponder 13 and a current measuring device 14 , for example via a common data bus and / or via separate data lines in bidirectional data exchange.

The representation of a current sensor is exemplary. It could just as well be other, especially electrically operated, sensors, for example, for temperature, pressure, brightness, humidity, smoke or any other type of sensors in combination with each other.

Furthermore, the sensor network comprises a network 2 over which the sensors 1 . 1 . 1 with each other as well as with a server 4 and two message brokers 5 . 5 ' are connected. Furthermore, in the present illustration, each current sensor is at the location 1 . 1 . 1 one RFID reader each 3 . 3 ' . 3'' provided, which is able to topic data to the respective RFID transponder 13 , ... of the corresponding current sensor 1 . 1 . 1 to send.

In another embodiment, a not shown in the drawing, mobile RFID reader ("Handheld Reader") instead of the illustrated stationary RFID reader 3 . 3 ' . 3'' be used by successively brought to the places where the fixed RFID reader shown in the drawing 3 . 3 ' . 3'' so as to keep the topic data to their respective RFID transponder 13 , ... transferred to.

The 2 shows a flowchart of an associated method.

The RFID reader 3 can store topic data in its data memory, which can, for example, affect the function and the location of the respective current measurement. However, these data can also be entered at short notice, in particular in the mobile RFID reader. Such a mobile RFID reader may be a smartphone or a tablet with a corresponding additional device.

These topic data are in method step A to the RFID transponder 13 of the current sensor 1 transfer.

Only now does the sensor have to 1 be booted in step B.

Then the microprocessor can 11 of the current sensor 1 in method step C, this topic data from the data memory of the RFID chip of the RFID transponder 13 Interrogate.

This is also particularly advantageous because, for example, in an update of the microprocessor 11 the data are held in the RFID transponder and are transmitted to the microprocessor again after the update. This greatly simplifies such an update process because all the current sensors 1 . 1 . 1 In a single operation, you can learn the same update together and then your individual data from the respective RFID transponder 13 , ... request.

In a first embodiment, the current sensor 1 have a given IPV6 address. This IPV6 address has such a large address space that it can be considered unique globally. In this case, the method step D is skipped.

In a second embodiment, which also includes method step D, the IP address may in particular also be an IPV4 address having a much smaller address space. In particular, this IPV4 address can be supplied to the current sensor by a DHCP server not shown in the drawing 1 assigned and over the network 2 be transferred to him.

By means of its thus obtained sensor IP address, the current sensor 1 now a request for a message broker 5 . 5 ' to the network 2 put. Any other network participant, ie another current sensor, 1 . 1 , the server 4 , the message broker 5 . 5 ' who knows an IP address of a message broker can answer this question and the current sensor in process step 4 send a broker IP address.

In the further course, the current sensor determines with its current measuring device 14 in method step G measured data. The microprocessor queries these measurement data, for example, from the current measuring device and forms in the method step H a message which has a topic and a content and preferably corresponds to a publisher-subscriber model, in particular the MQTT protocol. The content of the message includes at least part of the measurement data. The topic of the message includes at least part of the topic data.

In method step I, the message is from the sensor 1 to the message broker 5 transfer.

Each subscriber who subscribes to the topic of this message, for example, "Current at the power rail 23 in plant 3" gets the message from the message broker and can evaluate their content.

LIST OF REFERENCE NUMBERS

1, 1', 1''

 current sensor

11

 microprocessor

12

 Network Interface

13

 RFID transponder

14

 Current measurement device

2

 network

3

 RFID Reader

4

 server

5, 5'

 Message Broker

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006018174 A1 [0005]
• US 20120057581 A1 [0006]

Cited non-patent literature

• http://en.wikipedia.org/wiki/Sensornetz [0004]

Claims (10)

Sensor network comprising at least one RFID reader ( 3 ) for holding and sending topic data, as well as a network ( 2 ) with a server ( 4 ) and at least one sensor ( 1 ) as a client, comprising: - a measuring device ( 14 ) for acquiring measurement data; - an RFID transponder ( 13 ) for receiving the topic data from the RFID reader ( 3 ), wherein the RFID transponder ( 13 ) has an RFID chip with a writable data memory for storing the theme data; - one with the measuring device ( 14 ) and the RFID transponder ( 13 ) in bidirectional data exchange microprocessor ( 11 ) for requesting and storing the measurement data and the topic data and further for forming at least one message; and - one with the microprocessor ( 11 ) via a data line connected network interface ( 12 ) to send the message to the network ( 2 ). The sensor network of claim 1, wherein the message has a topic comprising at least a portion of the topic data and content comprising at least a portion of the measurement data.  Sensor network according to one of the preceding claims, wherein the message corresponds to a so-called "Publisher-Subscriber" model, in particular the so-called "MQTT" (Message Queue Telemetry Transport) format. A sensor network according to any one of the preceding claims, wherein at least one of the sensors represents a publisher, and wherein the network comprises at least one further client representing a subscriber. Sensor network according to claim 1, wherein the network comprises at least one message broker ( 5 ) having. Sensor network according to claim 5, wherein the message broker is used by the server ( 4 ) is formed. Sensor network according to one of claims 1 to 5, wherein the message broker by one of the sensors ( 1 . 1 . 1 ) is formed. Method for operating a sensor network according to one of the preceding claims, characterized by the following steps: A.) transmission of the topic data from the RFID reader ( 3 ) to the RFID transponder ( 13 ); B.) Boot the sensor ( 1 ); C.) Querying the topic data from the RFID transponder ( 13 ) and storing this topic data by the microprocessor ( 11 ); E.) Sending a request for a broker IP address by the sensor ( 1 ) via its network interface ( 12 ) to the network ( 2 ); F.) Respond to the request by a network participant by transmitting a broker IP address to the sensor ( 1 ); G.) Acquisition of measurement data by the measuring device ( 14 ) and transmit these measurement data to the microprocessor ( 11 ); H.) forming at least one message comprising a topic and a content, the topic including at least a portion of the topic data, and the content including at least a portion of the measurement data; I.) Sending the message from the sensor ( 1 ) via its network interface ( 12 ) using the broker IP address to the message broker ( 5 ). Method according to claim 8, wherein the method additionally comprises the following step: D.) Assigning and transmitting a sensor IP address, for example an IPV4 address, to the sensor ( 1 ). Method according to claim 8, characterized in that the sensor IP address is an IPV6 address.

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