KR102047134B1 - Wireless field bus system using vision light communication and data transmission method thereof - Google Patents

Abstract

Disclosed are a wireless field bus system using visible light communication and a data transmission method through the same. The disclosed wireless field bus system includes a master device; At least one slave device; And a plurality of end devices whose operation is controlled according to data transmitted from the master device via the slave device, wherein the slave device includes data for controlling the operation of the end device from the master device. Receives a frame, extracts data for controlling the operation of the end device, and transmits a visible light signal corresponding to the extracted data, wherein the terminating device receives the visible light signal and corresponds to the received visible light signal Acquire data, and the operation is controlled according to the acquired data.

Description

Wireless fieldbus system using visible light communication and data transmission method using the same {{WIRELESS FIELD BUS SYSTEM USING VISION LIGHT COMMUNICATION AND DATA TRANSMISSION METHOD THEREOF}

The present invention relates to a wireless field bus system, and more particularly, to a wireless field bus system using visible light communication and a data communication method through the same.

Field Bus is a technology for controlling a large number of end devices in an industrial environment. A control device such as a programmable logic controller (PLC) or a distributed control system (DCS) controls numerous field devices and data from the field devices. Perform the function of collecting it. Here, PLC, DCS is called a master (Master), generally implemented as an industrial PC, field equipment is called a slave (Slave).

The slave is usually connected to end devices such as sensors, actuators, valves, and motors that are commonly used in industrial fields, and performs various operations according to control commands received from the master. . 1 schematically shows the overall structure of a field bus.

The conventional wired field bus system provides high reliability and real time, but has a disadvantage in that the cost incurred during maintenance due to initial construction, wire shortage, hardware damage, and the like is very large. In addition, since all devices configuring the master and the slave are connected by wired cables, there are disadvantages in that the space is limited and the configuration of the device controller is complicated.

Since the problem of the wired field bus environment is a factor that makes the system difficult to operate, various studies have been conducted to integrate RF communication into the field bus system. However, since a wireless field bus system using RF communication currently uses a frequency of the 2.4 Ghz band, there is a problem in that it is not free from the effects of frequency interference and multipath signals.

The present invention provides a wireless field bus system for controlling each slave node and each device connected thereto using a visible light wireless communication method in an industrial field bus system, and a data communication method through the same.

According to an embodiment of the present invention, a field bus system includes: a master device; At least one slave device; And a plurality of end devices whose operation is controlled according to data transmitted from the master device via the slave device, wherein the slave device includes data for controlling the operation of the end device from the master device. Receives a frame, extracts data for controlling the operation of the end device, and transmits a visible light signal corresponding to the extracted data, wherein the terminating device receives the visible light signal and corresponds to the received visible light signal There is provided a wireless field bus system using visible light communication, wherein data is acquired and operation is controlled according to the obtained data.

The data frame may be periodically transmitted from the master device to the at least one slave device, sequentially transmitted in one direction to the at least one slave device starting from the master device, and then received again by the master device.

The data frame includes a data field in which data to be transmitted to each of the at least one slave device is recorded, and a type field in which a utilization type of data to be recorded in the data field is recorded. Is classified into one of a read type, a write type, and a read and write type to define an operation that needs to be performed for each slave device, and the slave device reads the read in the type field. When a read type is recorded, a first operation of extracting data related to itself from among the data recorded in the data field and transmitting a corresponding visible light signal to the end device is performed, and writing the data into the type field. Write) type, when the master device of the memory in the slave device is stored at a predetermined memory address Extracts data and writes the data to a data recording area allocated to the data field, and if the read and write type is recorded in the type field, the first operation; The operation and the second operation may be performed.

The data frame further includes a detection count field for detecting an operation error for each slave device, wherein the detection count field includes a case in which the data frame is normally received by the slave device and the data frame. The counting value may be increased and recorded based on at least one of the cases in which the slave device is normally operated according to the recorded data.

The slave device may include: a slave module configured to extract and store data for operation control of the end device from the data frame transmitted from the master device; A visible light transmission module which receives data for operation control of the end device from the slave module and modulates the received data into a data signal for visible light communication; And it may include a light source for emitting visible light corresponding to the data signal modulated by the visible light transmission module.

The master device searches for each slave device existing in the wireless field bus system through topology identification, generates the data frame to be delivered to each found slave device, and periodically checks the state of the slave module. If the data for controlling the end device operation is not normally stored in the slave device, the topology may be reconsidered.

According to another embodiment of the present invention, there is also provided a data transmission method in a field bus system including a master device, at least one slave device, and a plurality of end devices, wherein the slave device is connected to the plurality of end devices from the master device. Receiving a data frame including data for operation control of an end device associated with the device; The slave device extracting and storing data associated with the slave device as data for controlling the operation of the associated end device among the received data frames; And modulating a data signal corresponding to the stored data for use in visible light communication, and transmitting the visible light signal corresponding to the modulated data signal to the end device. A data transmission method in a bus system is provided.

According to an embodiment of the present invention, it is possible to provide a wireless field bus system for controlling each slave node and each device connected thereto using a visible light wireless communication method in an industrial field bus system, and a data communication method through the same.

According to the embodiment of the present invention, by using the visible light wireless communication method in the field bus system, it is possible to implement a wireless field bus system that is free from the influence of interference and can control various end devices without space restrictions.

1 schematically shows the overall structure of a field bus;
2 is a conceptual diagram of a wireless field bus system using visible light communication according to an embodiment of the present invention.
3 illustrates the structure of a superframe as a data frame transmitted for system control in a wireless field bus system using visible light communication;
4 is a block diagram of an overall functional structure of a wireless field bus using visible light communication according to an embodiment of the present invention.
5 is a data transmission flowchart in a wireless field bus system using visible light communication according to an embodiment of the present invention.

The present invention may be variously modified and have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing the present invention, when it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, numerals (eg, first, second, etc.) used in the description process of the present specification are merely identification symbols for distinguishing one component from another component.

In addition, in the present specification, when one component is referred to as "connected" or "connected" with another component, the one component may be directly connected or directly connected to the other component, but in particular It is to be understood that, unless there is an opposite substrate, it may be connected or connected via another component in the middle.

2 is a conceptual diagram of a wireless field bus system using visible light communication according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a wireless field bus system using visible light communication includes a master device 100 and at least one slave device 200 (in this example, a total of N slave devices 200-1, 200-2,... 200). -N) and at least one end device 300 associated with each slave device (in this example, a total of N end devices 300-1, 300-2, ... 300- associated with one slave device). N)).

The master device 100 may also be referred to as a system controller, and may be configured as, for example, a general purpose PC or an industrial PC. In addition, data communication is performed between the slave device 200 and the terminal device 300 connected thereto by a wireless method using visible light communication. In addition, data communication may be performed between the master device 100, the slave device 200, and each slave device by various wireless communication methods (for example, short-range wireless communication methods) as well as a wired method such as a wired cable. . 2, it is assumed that data communication is performed between the master device 100, the slave device 200, and each slave device by a wired method.

According to the exemplary embodiment of the present invention, the master device 100 may allow the LED (Light Emitting Diode) included in each slave device 200 to output a visible light signal for controlling the operation of the termination device 300. By controlling the operation, the operation of the terminal device that has received the visible light signal can be controlled. In this case, the control of the LED operation may be achieved by a superframe transmitted by the master device 100 to each slave device 200.

Here, the super frame refers to a command to be used to control the operation of the LED included in each slave device 200 in order to control the operation of the terminal device 300 by the master device 100. In order to refer to a data frame in which control data including control data are recorded, the term is separately named in the present invention. Therefore, the command data frame transmitted from the master device (or node) to the slave device (or node) with the aim of controlling the end device through the visible light communication method should be interpreted as the superframe of the present invention regardless of the term. .

In FIG. 2, an LED is used on the slave device 200 side and a PD (photo diode) is used on the end device 300 side for the visible light communication. However, the present invention is not limited thereto. That is, as long as the device can emit visible light, various light sources may be used in addition to the LED, and various light detection devices (ie, light receiving devices or devices) may be used. In addition, in performing visible light communication, a controllable light control (variable) element may be capable of controlling light on / off, optical intensity control, optical wavelength control through temperature control, and the like.

Hereinafter, specific functions and operations of the wireless field bus system according to the conceptual diagram illustrated in FIG. 2 and description of each component will be described later with reference to FIGS. 4 and 5. However, prior to describing FIGS. 4 and 5, each slave device from the master device 100 with reference to FIG. 3 in order to provide a clear understanding of a wireless field bus system using visible light communication according to an embodiment of the present invention. The superframe transmitted to 200 will be described.

3 is a diagram illustrating a structure of a superframe as a data frame transmitted for system control in a wireless field bus system using visible light communication. That is, the superframe for transmitting the LED 230 included in the slave device 200 is transmitted from the master device 100 to each slave device 200 according to an embodiment of the present invention as shown in FIG. It may have the same data frame structure.

Referring to FIG. 3, the superframe includes a destination address field, a source address field, a type field, a data field, and an error check field (FCS field) for error checking of the entire superframe. Include. However, the present invention is not limited thereto, and may include more attribute fields, and elements other than “Data” included in the data field and transmitted for each slave device may be partially omitted or variously modified. .

This superframe is transmitted from the master device 100 and received by the first slave device (referenced 200-1 assuming the case of FIG. 2), which is then the last slave device (200-N in FIG. 2). After being sequentially transmitted in one direction, it can be finally delivered back to the master device 100. Such a superframe may be periodically transmitted from the master device 100. However, it may be implemented as a bidirectional transmission method.

If it is assumed that the one-way circular transfer case as described above, the master device 100 can record the address of both the source address field and the destination address field. The address of each slave device 200 to which the superframe is to be transmitted may be recorded in a header in a data field. Therefore, as many addresses as the number of slave devices can be recorded in the header field.

Referring to FIG. 3, a data field includes a header and as many datagrams as the number of slave devices, and each datagram field should be received by each slave device 200. Data or data including data to be received from each slave device 200. Here, the data to be received by each slave device 200 may be data related to the LED operation control of each slave device, and the data to be received from each slave device 200 is a response received from the end device 300. Or it may be data relating to the state of the end device 300.

In addition, each datagram field may include a detection count field which is a node error check function field regarding whether each slave device 200 correctly received the corresponding data. For example, if each slave device 200 properly receives a superframe (in some cases, it may be determined whether or not normal operation is performed according to the corresponding data in the received superframe), a counting value in the detection count field Can be changed accordingly. For example, if the type field of the superframe is read or write, the counting value may be +1, and if it is read and write, the counting value may be +2. . Of course, other methods may be used. Therefore, according to the detection count field, it is possible to confirm whether each slave device is normally operated.

In addition, a data type for each slave device 200 may be recorded in the type field. Therefore, type information as many as the number of slave devices may be recorded in the type field. In this case, the data type may be classified into a read type, a write type, a read and write type.

In the read type, the slave device 200 extracts the information recorded in the “Data” and transmits the information to the end device 300 in the form of a visible light signal.

In the case of the write type, the specific data received from the end device 300 is recorded in “Data”. For example, assuming that specific data received from the end device 300 is stored in the memory of the slave device 200, the “Data” includes data desired by the master device 100 in the memory of the slave device 200. The stored memory address can be recorded initially. Accordingly, the slave device 200 may extract data recorded in the memory address transferred from the master device 100 and then record the extracted data in the “Data”. In this manner, the superframe in which recording is completed is transferred to the next slave device, and finally, the master device 100 is transferred.

In the case of the read and write type, “Data” may record i) data related to a command to be transmitted to the end device 300 and ii) memory address related to data to be read from the memory of the slave device 200. Accordingly, the slave device 300 extracts the information recorded in the “Data” in connection with the read operation and transmits the information to the end device 300 in the form of a visible light signal, and reads the data from the corresponding memory address in connection with the write operation. After writing to “Data”, it is transferred to the next slave device.

4 is a block diagram of an overall functional structure of a wireless field bus using visible light communication according to an embodiment of the present invention, and FIG. 5 is a flowchart of data transmission in a wireless field bus system using visible light communication according to an embodiment of the present invention. to be. 4 and 5, which will be described below, assume a case of a master device, and any one slave device and an end device which are operated and controlled in connection with the master device.

Hereinafter, a wireless field bus system according to an embodiment of the present invention will be described with reference to the block diagram of FIG. 4 centering on the data transmission flowchart of FIG. 5.

The master device 100 searches for each slave device 200 existing in the system by identifying the topology (S110 of FIG. 5). In addition, the master device 100 generates a superframe including control data related to a command for controlling the operation of the LED 230 included in each slave device 200 for visible light communication. 200).

Accordingly, the slave module 210 in the slave device 200 checks the datagram including the data about its node in the superframe (S120 of FIG. 5), and checks the data included in the datagram. It stores in memory (S125 of FIG. 5). When the storage is completed, the superframe is transferred to the slave device of the next node (S127 of FIG. 5).

Then, the slave module 210 transmits the data stored in the memory to the visible light transmitting module 220 according to the In / Out path set between itself and the visible light transmitting module 220 (S130 of FIG. 5). At this time, after the slave module 210 transmits the data signal to the visible light transmitting module 220 and checks whether the transmission is successful, if the visible light transmitting module 220 does not receive the data signal, the data is transmitted. The transmission is made again (S140 in FIG. 5).

Also, in this process, if the response from the visible light transmitting module 220 with respect to the corresponding data signal is not within a certain threshold, it is regarded as an error of the visible light transmitting module 220, and its status information is periodically received. The datagram may be recorded and transmitted to the master device 100 (S145, S152, S154, and S156 of FIG. 5).

In the normal response state, the visible light transmitting module 220 modulates the received data into a signal for visible light communication (S150 of FIG. 5), and the LED 230 transmits an optical signal according to the modulated signal (FIG. 5). S160].

The optical signal transmitted in this way is received by the PD 310 of the terminal device 300 (S170 in Fig. 5). The visible light receiving module 320 amplifies the data signal transmitted from the PD 310 and demodulates the amplified signal to extract original data (S180 and S185 of FIG. 5). At this time, the extracted original data is transmitted to the control equipment 330 to control the function operation (S190, S195 of Fig. 5).

Although the above has been described with reference to embodiments of the present invention, those skilled in the art may variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. And can be changed easily.

100: master unit
200: slave device
300: termination device
210: slave module
220: visible light transmission module
230: LED (Light Emitting Diode)
310: PD (Photo Diode)
320: visible light receiving module
330: Control Equipment

Claims (9)

In a field bus system,
Master device;
At least one slave device; And
It includes a plurality of end devices whose operation is controlled in accordance with the data transmitted from the master device via the slave device,
The master device transmits a superframe for controlling the operation of the LED so that the LED (Light Emitting Diode) included in each slave device can output a visible light signal to control the operation of the end device,
The superframe is periodically transmitted from the master device to the at least one slave device, sequentially transmitted in one direction to the at least one slave device starting from the master device, and then received again by the master device.
Each slave device receives the superframe and transmits a visible light signal to an end device to be controlled by using its address and data for controlling LED operation recorded in a data field included in the superframe,
The terminal device receiving the visible light signal acquires data corresponding to the received visible light signal, and the operation is controlled according to the acquired data. delete The method of claim 1,
The superframe includes a data field in which data to be transmitted to each of the at least one slave device is recorded, and a type field in which a utilization type of data to be recorded in the data field is recorded.
The type field is classified into one of a read type, a write type, and a read and write type to define an operation that needs to be performed for each slave device.
The slave device,
When the read type is recorded in the type field, a first operation of extracting data related to itself from the data recorded in the data field and transmitting a corresponding visible light signal to the end device,
When the write type is recorded in the type field, the master device extracts data stored in a predetermined memory address among the memories in the slave device, and stores the data stored in the data recording area allocated with respect to itself among the data fields. Perform a second operation of recording,
And the first and second operations are performed when the read and write types are recorded in the type field. The method of claim 3,
The superframe further includes a detection count field for detecting an operation error for each slave device.
The detection count field may increase and record a counting value based on at least one of when the superframe is normally received by the slave device and when the slave device is normally operated according to data recorded in the superframe. Wireless field bus system using visible light communication. The method of claim 1,
The slave device,
A slave module for extracting and storing data for operation control of the end device from the superframe transmitted from the master device;
A visible light transmission module which receives data for operation control of the end device from the slave module and modulates the received data into a data signal for visible light communication; And
And a light source for emitting visible light corresponding to the data signal modulated by the visible light transmitting module. The method of claim 5,
The master device searches for each slave device existing in the wireless field bus system through topology identification, generates the superframe to be delivered to each found slave device, and periodically checks the state of the slave module. And reconfirm the topology when data for controlling the end device operation is not normally stored in the slave device. A data transmission method in a field bus system comprising a master device, at least one slave device and a plurality of end devices.
The master device transmits a superframe for controlling LED operation so that a light emitting diode (LED) included in each slave device can output a visible light signal for controlling the operation of the end device. Periodically transmitted from the master device to the at least one slave device, sequentially transmitted unidirectionally to the at least one slave device from the master device, and then received back to the master device;
Receiving, by the slave device, the superframe, and transmitting a visible light signal to an end device to be controlled by using its address and data for controlling LED operation recorded in a data field included in the superframe; ;
The terminal device receives the visible light signal, the terminal device receiving the received visible light signal, the data corresponding to the received visible light signal, the operation is controlled according to the obtained data A data transmission method in a wireless field bus system using visible light communication. The method of claim 7, wherein
The superframe includes a data field in which data to be transmitted to each of the at least one slave device is recorded, and a type field in which a utilization type of data to be recorded in the data field is recorded. Is classified into any one of a read type, a write type, and a read and write type to define an operation that needs to be performed for each slave device.
The slave device,
When the read type is recorded in the type field, a first operation of extracting data related to itself from the data recorded in the data field and transmitting a corresponding visible light signal to the end device,
When the write type is recorded in the type field, the master device extracts data stored in a predetermined memory address among the memories in the slave device, and stores the data stored in the data recording area allocated with respect to itself among the data fields. Perform a second operation of recording,
When the read and write (Read & Write) type is recorded in the type field, the first operation and the second operation, characterized in that for performing a data transmission method in a wireless field bus system using visible light communication. The method of claim 7, wherein
Searching, by the master device, each slave device existing in the field bus system through topology determination;
And generating, by the master device, the superframe and transmitting the generated superframe to any one slave device of the found slave devices.

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