JP2022154103A - Communication device, communication system, and communication method - Google Patents

Abstract

To provide a communication device capable of performing communication with a low delay in a network constructed in wired and wireless manners.SOLUTION: A communication device 2, a component of a communication system 100, comprises a wired communication section 23 and a wireless communication section 24. The wired communication section 23 performs wired communication by operating as a slave unit for a wired master unit 1 operating as a communication device 2 of wired communication. The wireless communication section 24 performs wireless communication by operating as a communication device 2 for a wireless slave unit 3 operating as a slave unit of wireless communication. The wired master unit 1 and the wired communication section 23 are connected using a daisy chain method or a ring method. The wired communication is performed using a method in which when a frame transmitted by the wired master unit 1 passes through the wired communication section 23, data is input/output to/from the frame by the wired communication section 23. Communication between the wireless communication section 24 and the wireless slave unit 3 is short-range wireless communication, has a fixed cycle of data transmission/reception, and transmits/receives data in a previously assigned channel.SELECTED DRAWING: Figure 1

Description

The present invention mainly relates to a communication device that performs wireless communication and wired communication.

Patent Literature 1 discloses a communication system used for controlling industrial equipment installed in a factory or the like. This communication system communicates by a communication method such as EtherCAT (Ethernet or Control Automation Technology, a registered trademark), which is a wired network in which a plurality of devices are connected in a daisy chain method (a daisy chain method) or a ring method, or FL-net. conduct. EtherCAT communication has advantages of low delay and fixed period. One of the devices that make up the wired network also functions as a wireless communication base station. IEEE802.11a, b, g, and n are examples of standards for wireless communication between a base station and a child device.

JP 2019-29790 A

In wireless communication according to IEEE 802.11a, b, g, and n, for example, radio wave interference and wireless frame collision occur due to the spread of wireless communication over a wide area, and processing is performed to avoid such collision. Delays are likely to occur. Therefore, in the communication system described in Patent Document 1, the advantages of communication methods such as EtherCAT communication and FL-net cannot be fully utilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and a main object thereof is to provide a communication apparatus capable of performing communication with low delay in a wired and wireless network.

Means and Effects for Solving Problems

The problems to be solved by the present invention are as described above. Next, the means for solving the problems and the effects thereof will be described.

A first aspect of the present invention provides a communication device having the following configuration. A communication device constitutes a communication system. A communication system includes a wired parent device, a plurality of communication devices, and a plurality of wireless slave devices, and has a wired network in which the wired parent device and the plurality of communication devices are connected by a daisy chain method or a ring method. A communication device includes a wired communication unit and a wireless communication unit. The wired communication unit performs wired communication by operating as a child device with respect to the wired parent device. The wireless communication unit performs wireless communication by operating as a parent device with respect to the wireless slave device. Wired communication is performed in such a manner that when the frame transmitted by the wired parent device passes through the wired communication unit, the wired communication unit inputs and outputs data to the frame. The communication performed by the wireless communication unit and the wireless slave device is short-range wireless communication, in which the cycle of data transmission/reception is constant, and data is transmitted/received through a pre-assigned channel.

As a result, in wired communication, communication is performed using a common frame for devices connected by a daisy chain method or a ring method, resulting in low delay. Also in wireless communication, the period of data transmission/reception is constant, channels are allocated in advance, and short-range wireless communication is less likely to cause interference, resulting in low delay. As described above, low-delay communication becomes possible in a network in which wired and wireless are mixed.

In the communication device, it is preferable that the wireless communication unit collectively transmit data to a plurality of wireless slave units using a common channel.

As a result, data can be transmitted to a plurality of wireless slave units in a short period of time.

In the communication device, it is preferable that the wired communication unit inputs the data received by the wireless communication unit from the wireless slave device into the frame and transmits the frame to the wired master device.

As a result, the wired base unit can acquire data from the wireless slave unit with low delay.

According to the second aspect of the present invention, a communication system in which a plurality of said communication devices are connected to a wired parent device by wire, and each said communication device is capable of wireless communication with said one or more wireless slave devices. is provided. In the communication system, wireless communication between the wireless communication unit of the communication device and the one or more wireless slave units is performed independently of each other.

As a result, the wireless communication can be performed independently, so the waiting time for communication can be shortened, and as a result, the delay time can be reduced.

A third aspect of the present invention provides a communication system having the following configuration. That is, the communication system includes a wired master device, a plurality of communication devices, and a wireless slave device. The wired parent device operates as a wired communication parent device. The communication device operates as a child device of the wired parent device, performs wired communication with the wired parent device, and operates as a wireless communication parent device. The wireless slave device operates as a slave device of the communication device in wireless communication. The wired parent device and the plurality of communication devices are connected by wire using a daisy chain method or a ring method. Wired communication is performed in such a manner that when a frame transmitted by the wired parent device passes through the communication device, the communication device inputs and outputs data to the frame. The communication performed between the communication device and the wireless slave device is short-range wireless communication, in which the data transmission/reception cycle is constant and data is transmitted/received through a pre-assigned channel.

A fourth aspect of the present invention provides the following communication method. That is, the communication method includes a wired communication step and a wireless communication step. In the wired communication step, wired communication is performed between a wired parent device operating as a wired communication parent device and a plurality of communication devices operating as child devices of the wired parent device. In the wireless communication step, wireless communication is performed between a wireless slave device operating as a slave device for wireless communication and the communication device. The wired parent device and the plurality of communication devices are connected by wire using a daisy chain method or a ring method. Wired communication is performed in such a manner that when a frame transmitted by the wired parent device passes through the communication device, the communication device inputs and outputs data to the frame. The communication performed between the communication device and the wireless slave device is short-range wireless communication, in which the data transmission/reception cycle is constant and data is transmitted/received through a pre-assigned channel.

As a result, in wired communication, communication is performed using a common frame for devices connected by a daisy chain method or a ring method, resulting in low delay. In wireless communication as well, since the data transmission/reception cycle is constant and channels are allocated in advance, interference is less likely to occur, resulting in low delay. As described above, low-delay communication becomes possible in a network in which wired and wireless are mixed.

1 is a schematic diagram of a communication system according to one embodiment of the present invention; FIG. A table showing channels used in wireless communication, independent channel IDs, and shared channel IDs. FIG. 10 is a diagram showing processing in which a communication device communicates with one wireless slave device using an independent channel ID; FIG. 10 is a diagram showing processing in which a communication device communicates with a plurality of wireless slave devices using a shared channel ID; 4 is a flowchart showing processing performed when the communication device receives data from the wired parent device; 6 is a flowchart showing processing performed when the communication device transmits data to the wireless slave device;

Embodiments of the present invention will now be described with reference to the drawings. First, an outline of a communication system 100 will be described with reference to FIG.

A communication system 100 is provided in a facility such as a factory. Communication system 100 is used to manage and control industrial machine 4 . The industrial machine 4 is, for example, an industrial robot or a machine tool. A communication system 100 includes a wired master device 1 , a plurality of communication devices 2 , and a plurality of wireless slave devices 3 .

The wired master device 1 is a server or a personal computer, and transmits data regarding control or setting of the industrial machine 4 and receives data regarding the state of the industrial machine 4 .

The communication device 2 is a device capable of wired connection and wireless connection. The communication device 2 includes a processing device 21 , a storage device 22 , a wired communication section 23 and a wireless communication section 24 .

The processing device 21 is a CPU, SoC, or the like. The storage device 22 is a flash memory, HDD, SSD, or the like, and stores settings, programs, and the like used to control the communication device 2 . The processing device 21 controls the communication device 2 by reading a program stored in the storage device 22 into a RAM (not shown) and executing the program.

The wired communication unit 23 is a module for performing wired communication, and includes a connector, a signal converter, and the like. The wireless communication unit 24 is a module for wireless communication, and includes an antenna, an amplifier circuit, and the like.

The wireless slave device 3 is capable of wireless communication and is connected to the industrial machine 4 by wire. Thereby, the wireless slave device 3 functions as a repeater that wirelessly connects the industrial machine 4 to the communication system 100 . Specifically, for example, the wireless slave device 3 performs wired data input/output with the industrial machine 4 and wirelessly communicates the data with the communication system 100 . Note that the wireless slave device 3 may be incorporated in the housing of the industrial machine 4 .

A wired master device 1 and a plurality of communication devices 2 are connected by a wired network. Specifically, the wired master device 1 and the plurality of communication devices 2 are connected by a daisy chain method or a ring method. Also, the communication device 2 and the wireless slave device 3 are connected via a wireless network. Thus, the communication system 100 includes both wired and wireless networks.

Next, the communication system of the wired network will be explained. In this embodiment, the wired base unit 1 and the communication device 2 communicate with each other by EtherCAT (registered trademark). Specifically, the wired parent device 1 operates as a wired communication parent device (master device), and the communication device 2 operates as a wired communication child device (slave device). The wired base unit 1 and the plurality of communication devices 2 can support fixed-cycle and low-delay communication by adopting the communication method of the wired network.

In the communication system of this embodiment, the wired master device 1 transmits a frame 10 shown in FIG. A frame 10 transmitted by the wired master device 1 returns to the wired master device 1 via all the communication devices 2 forming the wired network. This frame 10 includes a header, a plurality of datagrams, an FCS for error detection, and the like. One datagram corresponds to one communication device 2 . Based on the information described in the datagram, the communication device 2 stores response data in the frame 10 and stores data described in the frame 10 (details will be described later).

In general wired LAN communication, there are a plurality of entities that perform transmission, and frames are sent to various destinations. As a result, a delay occurs and the delay time also varies. In this regard, in the communication system of the present embodiment, the transmission is performed only by the wired base unit 1, and the number of frame transmission paths is one, so delay is unlikely to occur. In this embodiment, EtherCAT is used as a wired network, but other communication methods for performing the same type of communication, such as Mechatrolink (registered trademark) or SERCOS (registered trademark), may be used.

Next, the communication method of the wireless network will be described with reference to FIGS. 2 to 4. FIG. In this embodiment, wireless communication is performed between the communication device 2 and the wireless slave device 3 using ANT communication. ANT communication is a representative example of short-range wireless communication.

ANT communication is a master-slave system, and all communication devices 2 operate as masters of ANT communication. In other words, in the example shown in FIG. 1, there are three wireless networks for ANT communication, each having the communication devices 2A, 2B and 2C as master devices. In ANT communication, channels and IDs are assigned in advance. Therefore, since processing for searching for an available channel during communication is not required, ANT communication is less likely to cause delays than methods that change channels according to communication conditions. In ANT communication, the range of wireless communication is short distance (for example, 5 m to 10 m), and communication between master and slave can be performed at a predetermined cycle (fixed cycle).

FIG. 2 shows the channels and IDs assigned to the communication device 2 and the wireless slave device 3 . As shown in FIG. 1, a communication device 2A communicates with wireless slave devices 3A and 3B. The wireless communication parent and child devices communicate using the same channel. Therefore, the channel of the communication device 2A and the channel of the wireless slave devices 3A and 3B are the same. Similarly, the communication device 2B communicates with the wireless slave devices 3C, 3D and 3E using the same channel.

In ANT communication, one-to-one communication using independent channel IDs is possible. When using an independent channel ID, after setting a predetermined independent channel ID in the communication device 2 and the wireless slave device 3, ANT communication is performed as shown in FIG. Specifically, after the communication device 2 and the wireless slave device 3 are paired, wireless communication is started. One time (one slot) communication is performed as a pair of transmission and reception. That is, the wireless slave device 3 transmits data to the communication device 2 after the communication device 2 serving as the parent device transmits data to the wireless slave device 3 . In addition, the communication cycle of one slot is also determined in advance.

ANT communication also allows one-to-many communication using a shared channel ID. When using a shared channel ID, after setting a predetermined shared channel ID in the communication device 2 and the plurality of wireless slave devices 3, ANT communication is performed as shown in FIG. Specifically, after pairing is performed between the communication device 2 and the plurality of wireless slave devices 3, wireless communication is started. In one communication, transmission and reception are performed as a pair. That is, after the communication device 2 transmits data to the plurality of wireless slave devices 3 by broadcasting, the wireless slave device 3 transmits data to the communication device 2 by broadcasting. A communication cycle is also predetermined.

Since the communication cycle is predetermined, it is possible to reduce variations in transmission time and shorten delay time. Further, if a channel is allocated in advance and wireless communication is performed at a predetermined cycle, other communication methods may be used without being limited to ANT communication.

Next, the flow of wired communication and wireless communication performed by the communication device 2 will be described with reference to FIGS. 5 and 6. FIG. First, with reference to FIG. 5, the processing performed when the communication device 2 receives the frame 10 from the wired master device 1 will be described.

When receiving wired communication data (frame 10) (S101), the communication device 2 determines whether or not the device address of the datagram matches its own address (S102). If the device address of the datagram matches its own address, the communication device 2 determines whether the datagram includes a write command (S103).

A datagram contains either a write command or a read command. The write command instructs the communication device 2 that received the frame 10 to write the data contained in the datagram to the wireless slave device 3 (resultingly, the industrial machine 4) that is the control destination. is a command. In this embodiment, when the datagram includes a write command, the communication device 2 stores the specified data in the wireless transmission buffer (S104). A wireless transmission buffer is an area for temporarily storing data for wireless transmission. Specifically, the wireless transmission buffer is implemented by the storage device 22 .

If the datagram does not contain a write command (in other words, if it contains a datagram read command), the communication device 2 determines whether data is stored in the wireless reception buffer (S105). The wireless reception buffer is an area for temporarily storing data wirelessly received from the industrial machine 4 via the wireless slave device 3 . Specifically, the wireless reception buffer is realized by the storage device 22 . When data is stored in the wireless reception buffer, the communication device 2 stores this data in the datagram of the frame 10 transmitted from the wired master device 1 (S106).

Next, with reference to FIG. 6, the process of performing wireless communication between the communication device 2 and the wireless slave device 3 will be described.

As described above, wireless communication between the communication device 2 and the wireless slave device 3 is performed at predetermined intervals. The communication device 2 determines whether or not the communication cycle has arrived (S201). When determining that the communication cycle has arrived, the communication device 2 determines whether data is stored in the wireless transmission buffer (S202).

When data is stored in the wireless transmission buffer, the communication device 2 transmits this data to the wireless slave device 3 (S203). On the other hand, if no data is stored in the wireless transmission buffer, the communication device 2 determines whether or not there is data received from the wireless slave device 3 (S204). If there is data received from the wireless slave device 3, the communication device 2 stores this data in the wireless reception buffer (S205).

By repeating each process shown in FIGS. 5 and 6, the communication device 2 transmits data received from the wired master device 1 to the industrial machine 4, and transmits data received from the industrial machine 4 to the wired master device 1. You can Moreover, as described above, the wired communication and the wireless communication of the present embodiment are low-delay and periodic. Therefore, it is possible to appropriately control the industrial machine 4 which is greatly affected by delays and the like.

As described above, the communication device 2 of this embodiment configures the communication system 100 . The communication system 100 includes a wired master device 1, a plurality of communication devices 2, and a plurality of wireless slave devices 3. The wired master device 1 and the plurality of communication devices 2 are connected by a daisy chain method or a ring method. have a network; The communication device 2 includes a wired communication section 23 and a wireless communication section 24 . The wired communication unit 23 operates as a child device with respect to the wired master device 1 and performs wired communication. The wireless communication unit 24 performs wireless communication with the wireless slave device 3 by operating as a master device. Wired communication is performed by a method in which the wired communication unit 23 inputs and outputs data to the frame 10 when the frame 10 transmitted by the wired master device 1 passes through the wired communication unit 23 . The communication between the wireless communication unit 24 and the wireless slave device 3 is short-range wireless communication, in which the data transmission/reception cycle is constant, and data is transmitted/received through a pre-assigned channel.

As a result, in wired communication, communication is performed using a common frame 10 for devices connected in a daisy chain system or a ring system, resulting in low delay. Also in wireless communication, the period of data transmission/reception is constant, channels are allocated in advance, and short-range wireless communication is less likely to cause interference, resulting in low delay. As described above, low-delay communication becomes possible in a network in which wired and wireless are mixed.

In the communication device 2 of this embodiment, the wireless communication unit 24 collectively transmits data to the plurality of wireless slave units 3 using a common channel.

As a result, data can be transmitted to a plurality of wireless slave units 3 in a short period of time.

In the communication device 2 of the present embodiment, the wired communication unit 23 inputs the data received by the wireless communication unit 24 from the wireless slave device 3 into the frame 10 and transmits the frame 10 to the wired master device 1 .

As a result, the wired master device 1 can acquire the data of the wireless slave device with low delay.

Although the preferred embodiment of the present invention has been described above, the above configuration can be modified as follows, for example.

In the above-described embodiment, the communication device 2 performs wireless communication with the wireless slave device 3. However, a plurality of communication devices 2 and a plurality of wireless slave devices 3 cooperate to perform wireless communication. A case of doing so will be described. For example, the wired master device 1 may want to manage and control a plurality of industrial machines 4 at the same timing as much as possible. Specifically, when industrial robots are used to efficiently manufacture multiple products at the same time, it is necessary for multiple industrial robots to perform the same action (for example, grabbing an object) at the same timing. . 1 and 2, the wireless slave devices 3A to 3E connected by wires to a plurality of industrial machines 4 need to communicate with the industrial machines 4 to which they are connected at the same timing as much as possible. In such a case, when wireless communication is performed between one communication device 2 and a plurality of wireless slave devices 3 (3A to 3E), the load on the communication device 2 increases and delays may occur. It may be difficult to manage and control a plurality of industrial machines 4 at the same timing as much as possible. Therefore, a plurality of communication devices 2 (for example, 2A and 2B), the communication device 2A communicates independently with the wireless slave devices 3A and 3B, and the communication device 2B independently communicates with the wireless slave devices 3C, 3D and 3E. can be lowered, and the delay time can be reduced.

As a result, the wireless communication can be performed independently, so the waiting time for communication can be shortened, and as a result, the delay time can be reduced.

Although the preferred embodiments of the present invention have been described above, the above configuration can be modified, for example, as follows.

The facility where the communication system 100 is installed is not limited to a factory, and may be an office, a store, or the like.

The flowcharts shown in the above embodiments are examples, and some of the processes may be omitted, the contents of some of the processes may be changed, or new processes may be added.

INDUSTRIAL APPLICABILITY The present invention can be applied to a wireless communication system that requires low delay in a mixed wired and wireless network. In particular, it is useful for wired networks (for example, EtherCAT) connected in a daisy chain system or a ring system.

REFERENCE SIGNS LIST 1 wired parent device 2 communication device 3 wireless slave device 21 processing device 22 storage device 23 wired communication unit 24 wireless communication unit 100 communication system

Claims (6)

A communication device for a communication system in a wired network comprising a wired parent device, a plurality of communication devices, and a plurality of wireless slave devices, wherein the wired parent device and the plurality of communication devices are connected by a daisy chain method or a ring method. and
a wired communication unit that operates as a child device and performs wired communication with respect to the wired parent device;
a wireless communication unit that operates as a parent device and performs wireless communication with the wireless slave device;
with
When the frame transmitted by the wired parent device passes through the wired communication unit, the wired communication unit inputs and outputs data to and from the frame.
A communication apparatus characterized in that the communication performed by the wireless communication unit and the wireless slave device is short-range wireless communication, the cycle of data transmission and reception is constant, and data is transmitted and received through a pre-assigned channel. . A communication device according to claim 1,
The communication device, wherein the wireless communication unit collectively transmits data to a plurality of wireless slave units using a common channel. The communication device according to claim 1 or 2,
The communication apparatus, wherein the wired communication unit inputs data received by the wireless communication unit from the wireless slave device into the frame and transmits the frame to the wired master device. A plurality of the communication devices according to any one of claims 1 to 3 are connected to a wired master device by wire, and each of the communication devices is capable of wireless communication with the one or more wireless slave devices. In a communication system,
A communication system, wherein wireless communication between the wireless communication unit of the communication device and the one or more wireless slave units is performed independently of each other. A wired parent device that operates as a wired communication parent device,
a plurality of communication devices that operate as child devices of the wired parent device, perform wired communication with the wired parent device, and operate as wireless communication parent devices;
a wireless slave device that operates as a slave device of the communication device in wireless communication;
with
the wired parent device and the plurality of communication devices are connected by wire using a daisy chain method or a ring method;
Wired communication is performed by a method in which the communication device inputs and outputs data to the frame when the frame transmitted by the wired parent device passes through the communication device,
A communication system according to claim 1, wherein the communication performed between the communication device and the wireless slave device is short-distance wireless communication, data is transmitted and received at a constant cycle, and data is transmitted and received through a pre-assigned channel. a wired communication step of performing wired communication between a wired parent device operating as a wired communication parent device and a plurality of communication devices operating as child devices of the wired parent device;
a wireless communication step of performing wireless communication between a wireless slave device operating as a wireless communication slave device and the communication device;
including
the wired parent device and the plurality of communication devices are connected by wire using a daisy chain method or a ring method;
Wired communication is performed in such a manner that when the frame transmitted by the wired parent device passes through the communication device, the communication device inputs and outputs data to the frame,
A communication method according to claim 1, wherein the communication performed between the communication device and the wireless slave device is short-range wireless communication, data is transmitted and received at a constant cycle, and data is transmitted and received through a pre-assigned channel.

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