JP6233021B2 - Communication distribution device - Google Patents

Description

  The present invention relates to a communication distribution device, and is suitable for application to, for example, a switching hub.

  In recent years, EtherCAT (Ether for Control Automation Technology) (registered trademark), which is an Ethernet (registered trademark) -based fieldbus system, has attracted attention as a master-slave communication method.

  In Ethercat (registered trademark), each slave processes a communication frame that periodically flows on a network (hereinafter referred to as a fixed-period frame) on the fly. Specifically, when each slave receives a fixed-period frame, it reads / writes data from / to an area allocated to itself in the fixed-period frame and simultaneously forwards the communication frame to the next slave.

  Data transmission / reception processing in the slave is performed at high speed by an Ethercat (registered trademark) slave controller mounted in the slave. For this reason, the network performance of the slave does not depend on the microcomputer performance of the slave. Usually, the delay of a fixed-cycle frame in each slave is only about a few [ns], thereby ensuring high-speed data transmission and real-time performance.

  Such high speed and real-time performance of data transmission of Ethercat (registered trademark) is useful in factories and plants that require real-time control, and in recent years, real-time performance of communication systems to which Ethercat (registered trademark) is applied. Many various inventions for guaranteeing the above have been proposed (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2011-77751

  By the way, when using a master-slave type industrial communication protocol such as the Ethercat (registered trademark) as a communication method of the remote I / O system, a general-purpose Ethernet (registered trademark) switch is used to make the master redundant. The communication is distributed to a plurality of masters.

  In this case, in recent industrial communication protocols, Ethernet (registered trademark) is used for the physical layer and data link layer, but general-purpose Ethernet (registered trademark) switches are all of the industrial Ethernet (registered trademark) protocol. It does not correspond to.

  For example, in the Ethercat (registered trademark) protocol, when communication with the connected next-stage communication device (control device or slave) is interrupted, the communication frame transferred from the previous communication device is transmitted to the next-stage communication device. A loopback function that returns to the previous communication device without transferring to the device and a hot connect function that can add or delete slaves during system operation are specified. No such loopback function or hot connect function is installed.

  For this reason, for example, in a remote I / O system to which the Ethercat (registered trademark) system is applied as a communication system, when a general-purpose Ethernet (registered trademark) switch is used as a communication distribution device that distributes communication to a plurality of masters, If communication between the Ethernet (registered trademark) switch and the next-stage communication device connected to the Ethernet (registered trademark) switch is interrupted, the Ethernet (registered trademark) switch is assigned to the next-stage communication device. The periodic frame cannot be transferred, and the periodic frame disappears between the Ethernet (registered trademark) switch and the communication device at the next stage.

  As described above, when using a communication distribution device that does not support the communication method of the remote I / O system when attempting to make the master redundant, a problem may occur in communication, resulting in a decrease in reliability of the entire system. There is.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose a communication distribution device capable of improving the reliability of the entire system.

  In order to solve this problem, in the present invention, in a remote I / O system to which a master-slave industrial communication protocol is applied, at least two master devices and a network to which one or more slave devices are connected are provided. And a first transmission / reception unit that transmits and receives a communication frame to and from the corresponding master device, and the network is connected to the communication distribution device. A third transmission / reception unit that transmits / receives the communication frame to / from the slave device via the network, and is connected so as to be able to communicate with the third transmission / reception unit bidirectionally, the master device or the slave Slave controller that executes communication processing for communicating with an apparatus according to the industrial communication protocol Distributing the communication frame given to one of the corresponding first or second transmission / reception units from one of the master devices to the other second or first transmission / reception unit and the slave controller; The first and second transmission frames are distributed to the first and second transmission / reception units via the slave controller, respectively, from the connected slave device to the third transmission / reception unit. A branch connection unit for connecting the transmission / reception unit and the slave controller is provided.

  In such a communication distribution device, the communication frame transmitted from the master device is transmitted to the other master device and the slave device, respectively, and the communication frame transmitted from the slave device is transmitted to each master device. Thereby, redundancy of the master device can be achieved. In this case, since the slave controller supports the industrial communication protocol applied to the remote I / O system, there is no problem in communication between the master device and the slave device.

  ADVANTAGE OF THE INVENTION According to this invention, the communication distribution apparatus which can improve the reliability as the whole system is realizable.

It is a block diagram which shows the whole structure of the remote I / O system by this Embodiment. (A)-(E) is a conceptual diagram which shows the frame format of the fixed period frame in an Ethercat (trademark) protocol. It is a block diagram which shows the structure of the 1st and 2nd switching hub. It is a block diagram which shows the structure of the 1st-4th selector part. It is a state transition diagram with which it uses for description of the state of an output arbitration control part. It is a block diagram which shows schematic structure of the 1st and 2nd switching hub. It is a block diagram with which it uses for description of the flow of a fixed period frame in the 1st and 2nd switching hub. It is a block diagram with which it uses for description of the flow of a fixed period frame in the 1st and 2nd switching hub. It is a block diagram with which it uses for description of the flow of a fixed period frame in the 1st and 2nd switching hub.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Remote I / O System According to this Embodiment FIG. 1 shows a schematic configuration of a remote I / O system 1 for a gas turbine power plant. The remote I / O system 1 is a communication system to which an Ethercat (registered trademark) protocol is applied as a communication protocol, and includes two redundant control devices (hereinafter referred to as first and second control devices) installed in a control room. (Referred to as a second control device) 2A, 2B.

  1st and 2nd control apparatus 2A, 2B is a control apparatus which controls the whole gas turbine power generation plant, respectively, main CPU (Central Processing Unit) 10A, 10B, 1st master CPU11A, 11B, 2nd Master CPUs 12A and 12B.

  The main CPUs 10A and 10B are processors that control the operation of the entire first or second control device 2A or 2B, and the first master CPUs 11A and 11B and the second master connected via the internal buses 13A and 13B. Various types for controlling a gas turbine (not shown) installed at a remote site based on sensor outputs of various types of sensors at the remote site collected by the CPUs 12A and 12B and various programs stored in a memory (not shown). Execute control processing.

  The first master CPUs 11A and 11B and the second master CPUs 12A and 12B are processors that function as masters in the connected A-system or B-system networks 3A and 3B. The first master CPUs 11A and 11B are connected to an A-system network 3A having a ring-type network topology, and the second master CPUs 12A and 12B are connected to a B-system network 3B having a ring-type network topology. .

  The A-system network 3A includes first and second switching hubs 20A and 21A and first and fourth media converters 22A and 25A respectively disposed in a control room, and second and third switching nodes disposed at a remote site. Media converters 23A and 24A, an AI (Analog Input) slave 26A, an AO (Analog Output) slave 27A, a DI (Digital Input) slave 28A, and a DO (Digital Output) slave 29A.

  And between the first master CPU 11A of the first switching hub 20A and the first controller 2A, between the first master CPU 11B of the first switching hub 20A and the second controller 2B, and the second switching hub. Between the first master CPU 11A of 21A and the first control device 2A, and between the first master CPU 11B of the second switching hub 21A and the second control device 2B, Ethernet such as a 100BASE-TX cable (registration) Trademarks) are connected via category 5 or higher cables.

  Similarly, between the first switching hub 20A and the first media converter 22A, between the second media converter 23A and the AI slave 26A, between the AI slave 26A and the AO slave 27A, and between the AO slave 27A and the DI slave 28A. Also, between the DI slave 28A and the DO slave 29A, between the DO slave 29A and the third media converter 24A, and between the fourth media converter 25A and the second switching hub 21A, Ethernet (registered trademark) category 5 or more Connected via cable.

  On the other hand, the first media converter 22A and the second media converter 23A and the third media converter 24A and the fourth media converter 25A are connected via an optical cable 32 such as a 100BASE-FX cable, respectively. Thus, even when the remote site is located away from the control room, signal attenuation during communication between the control room and the remote site can be suppressed.

  Similarly to the A-system network 3A, the B-system network 3B includes the first and second switching hubs 20B and 21B and the first and fourth media converters 22B and 25B disposed in the control room, respectively, And the second and third media converters 23B and 24B, the AI slave 26B, the AO slave 27B, the DI slave 28B, and the DO slave 29B.

  Then, between the first switching hub 20B and the second master CPU 12A of the first control device 2A, between the first switching hub 20B and the second master CPU 12B of the second control device 2B, and the second switching hub. 21B and the second master CPU 12A of the first control device 2A, and between the second switching hub 21B and the second master CPU 12B of the second control device 2B are Ethernet category 5 or higher, respectively. The other slaves are connected to each other in the same way as the A-system network 3A.

  The first switching hubs 20A and 20B and the second switching hubs 21A and 21B are communication distribution devices on which Ethercat (registered trademark) slave controllers are mounted. Although not shown in FIG. 1, the first switching hubs 20A and 20B and the second switching hubs 21A and 21B are connected to a communication monitoring device such as a personal computer for monitoring communication. Each of the first to fourth media converters 22A to 25A and 22B to 25B is an optical transmission device on which an Ethercat (registered trademark) slave controller is mounted.

  The AI slaves 26A and 26B, the AO slaves 27A and 27B, the DI slaves 28A and 28B, and the DO slaves 29A and 29B are I / O slaves each equipped with an Ethercat (registered trademark) slave controller. In the following, the AI slave 26A, the AO slave 27A, the DI slave 28A, and the DO slave 29A are collectively referred to as an I / O slave 30A, and the AI slave 26B, the AO slave 27B, the DI slave 28B, and the DO slave 29B are appropriately referred to These are collectively referred to as I / O slave 30B.

  One or a plurality of AI slaves 26A, 26B are provided on the A-system and B-system networks 3A, 3B, respectively, corresponding to the analog sensors arranged at the remote site. The AI slaves 26A and 26B are configured to include an analog / digital converter (not shown), and digitally convert the sensor output of the corresponding analog sensor provided via the corresponding signal distributor 31, and thus obtained. The digitized sensor output (hereinafter referred to as sensor information) is transmitted from the first or second master CPU 11A, 11B, 12A, 12B of the first or second control device 2A, 2B as described later. Has a function of storing in an area allocated to itself in a fixed-period frame. Note that the “area allocated to itself in the fixed-cycle frame” here refers to an EtherCAT Datagram for the slave described later with reference to FIG. The same applies to the following.

  One or a plurality of AO slaves 27A and 27B are provided on the A-system and B-system networks 3A and 3B, respectively, corresponding to the analog devices to be controlled such as actuators arranged at the remote site. The AO slaves 27A and 27B are configured to include a digital / analog converter, and read out the control information stored in the area allocated to itself in the fixed-cycle frame as will be described later, and convert it into an analog signal. The analog control information is transmitted to the corresponding signal distributor 31. In this case, the signal distributor 31 calculates the average value of the analog control information given from the corresponding AO slaves 27A and 27B of the A-system and B-system networks 3A and 3B, and calculates the calculated result of the corresponding control target. Send to analog device. However, the signal distributor 31 has a larger or smaller value of analog control information given from the corresponding AO slaves 27A and 27B of the A-system and B-system networks 3A and 3B, or one of the predetermined networks. Only the analog control information given from the 3A and 3B AO slaves 27A and 27B may be transmitted to the corresponding analog device to be controlled.

  One or a plurality of DI slaves 28A and 28B are provided on the A-system and B-system networks 3A and 3B in correspondence with the respective digital sensors arranged at the remote site. The DI slaves 28A and 28B have a function of storing the sensor output (sensor information) of the corresponding digital sensor given through the corresponding signal distributor 31 in the area allocated to itself in the fixed period frame.

  One or a plurality of DO slaves 29A and 29B are provided on the A-system and B-system networks 3A and 3B, respectively, corresponding to the digital devices to be controlled arranged at the remote site. The DO slaves 29 </ b> A and 29 </ b> B have a function of reading out control information stored in an area assigned to itself in a fixed-cycle frame and sending it to the corresponding signal distributor 31 as described later. In this case, the signal distributor 31 calculates the average value of the control information given from the corresponding DO slaves 29A and 29B of the A-system and B-system networks 3A and 3B, and the calculated result is the corresponding digital object to be controlled. Send to device. However, the signal distributor 31 has a larger or smaller value of control information given from the corresponding DO slaves 29A and 29B of the A-system and B-system networks 3A and 3B, or one of the predetermined networks. Only the control information given from the 3A and 3B DO slaves 29A and 29B may be transmitted to the corresponding digital device to be controlled.

  In the remote I / O system 1 having such a configuration, a master-slave relationship between the first master CPU 11A of the first control device 2A and the first master CPU 11B of the second control device 2B in the A-system network 3A. The master-slave relationship between the second master CPU 12A of the first control device 2A and the second master CPU 12B of the second control device 2B in the B-system network 3B is controlled by the master-slave switching unit 4. . The master-slave switching unit 4 normally sets the first and second master CPUs 11A, 12A of the first control device 2A as the main system, and the first and second master CPUs 11B, 2B of the second control device 2B. 12B is set as a slave.

  The first master CPU 11A of the first control device 2A set as the main system normally communicates with all I / O slaves 30A existing on the A-system network 3A. ) A fixed-cycle frame defined by the standard is transmitted to the first switching hub 20A of the A-system network 3A at a fixed cycle (for example, 1 [ms] cycle). Further, the first switching hub 20A transfers the periodic frame transmitted from the first control device 2A to the first master CPU 11B of the second control device 2B and the first media converter 22A of the A-system network 3A. To do.

  The first media converter 22A converts the fixed-cycle frame transferred from the first switching hub 20A into an optical signal, and transmits the optical signal to the second media converter 23A via the optical cable 32. The second media converter 23A converts the optical signal transmitted from the first media converter 22A into an electrical signal, and transfers the fixed-period frame thus obtained to the AI slave 26A.

  When the AI slave 26A receives the fixed-cycle frame, the AI slave 26A acquires it after the previous fixed-cycle frame is transferred to the area allocated to itself in the fixed-cycle frame until the current fixed-cycle frame is received. Stored sensor information. Then, the AI slave 26A transfers the fixed-cycle frame storing the sensor information to the next-stage slave (AO slave 27A in FIG. 1).

  Further, when the AO slave 27A receives the fixed-cycle frame, the AO slave 27A reads the control information stored in the area allocated to itself within the fixed-cycle frame, converts the read control information into an analog signal, and corresponding signal distributor 31. And the periodic frame is transferred to the slave at the next stage (DI slave 28A in FIG. 1).

  When the DI slave 28A receives the fixed-cycle frame, the DI slave 28A acquires the period from the last transfer of the fixed-cycle frame to the area allocated to itself in the fixed-cycle frame until the reception of the current fixed-cycle frame. Stored sensor information. Then, the DI slave 28A transfers the fixed-cycle frame storing the sensor information to the next-stage slave (DO slave 29A in FIG. 1).

  Also, when the DO slave 29A receives the fixed cycle frame, the DO slave 29A reads the control information stored in the area allocated to itself in the received fixed cycle frame, and sends the read control information to the corresponding signal distributor 31. At the same time, the fixed-cycle frame is transferred to the slave at the next stage (the third media converter 24A in FIG. 1).

  The third media converter 24A converts the received periodic frame into an optical signal, and transmits the optical signal to the fourth media converter 25A in the control room via the optical cable 32. The fourth media converter 25A converts the optical signal transmitted from the third media converter 24A into an electrical signal, and transfers the fixed-period frame thus obtained to the second switching hub 21A.

  The second switching hub 21A sends the fixed-cycle frame transferred from the fourth media converter 25A to the first master CPU 11A of the first control device 2A and the first master CPU 11B of the second control device 2B. To do. Then, the first master CPU 11A of the first control device 2A that has received the fixed-cycle frame reads the sensor information stored in the fixed-cycle frame by the AI slave 26A and the DI slave 28A, and delivers the read sensor information to the main CPU 10A. .

  On the other hand, at this time, the second master CPU 12A of the first control device 2A also communicates with all the I / O slaves 30B existing on the B-system network 3B, like the first master CPU 11A. The periodic frame defined in the Cat (registered trademark) standard is periodically transmitted (with the same period as the period in which the first master CPU 11A transmits the periodic frame to the A-system network 3A). To the switching hub 20B. Further, the first switching hub 20B of the B-system network 3B transfers such a periodic frame to the second master CPU 12B of the second control device 2B and the first media converter 22B of the B-system network 3B.

  As a result, the periodic frames are sequentially transferred on the B-system network 3B in the same manner as the A-system network 3A described above, and the second frame of the first control device 2A is transmitted via the B-system second switching hub 21B. The master CPU 12A is returned to. Thus, the second master CPU 12A of the first control device 2A that has received this fixed-cycle frame reads the sensor information stored in the fixed-cycle frame by the AI slave 26B and the DI slave 28B on the B-system network 3B, The read sensor information is delivered to the main CPU 10A.

  The main CPU 10A has commands and parameters for controlling each control target at the remote site to a predetermined state based on the sensor information given from the first master CPU 11A and the sensor information given from the second master CPU 11A. And the like, and the generated control information is delivered to the first and second master CPUs 11A and 12A. Thus, each of the first and second master CPUs 11A and 12A generates a fixed-cycle frame in which each of these control information is stored in a corresponding area, and the generated fixed-cycle frame is transmitted to the A system or the B system at the next transmission timing. The data is transmitted to the first switching hubs 20A and 20B of the networks 3A and 3B.

  In this way, the first or second control device 2A, 2B controls each control target at the remote site to a predetermined state based on the sensor output of each analog sensor or each digital sensor arranged at the remote site. .

  On the other hand, in the second control device 2B set as the slave at this time, the periodic frame transmitted from the second switching hub 21A of the A-system network 3A to the first master CPU 11B, and the B-system network 3B Based on the fixed-cycle frame transmitted from the second switching hub 21B to the second master CPU 12B, processing similar to that of the first control device 2A described above is executed.

  However, the first master CPU 11B and the second master CPU 12B of the second control device 2B transmit to the first switching hubs 20A and 20B a fixed-cycle frame storing the above-described control information generated by such processing. Discard without. Therefore, in the remote I / O system 1, only the periodic frames output from the first and second master CPUs 11 </ b> A and 12 </ b> A of the first control device 2 </ b> A set as the main system are normally A system or B It is transmitted on the networks 3A and 3B.

  On the other hand, when a failure occurs in the first or second master CPU 11A, 12A of the first control device 2A set as the main system, the master-slave switching device 4 is the first or second in which the failure has occurred. First and second control devices so that the masters of the A-system or B-system networks 3A and 3B to which the master CPUs 11A and 12A are connected are the first or second master CPUs 11B and 12B of the second control device 2B. Switches the master / slave setting of 2A and 2B.

  Then, the first or second master CPU 11B, 12B of the second control device 2B switched to the main system thereafter uses the A or B system first switching hub to generate the fixed-cycle frame generated as described above. The first or second master CPU 11A, 12A of the first control device 2A, which has been transmitted to 20A, 20B and switched to the secondary system, transmits the generated periodic frame to the first switching hub. Discard without transmitting to 20A, 20B. As a result, when the master-slave relationship between the first or second master CPU 11A, 12A of the first control device 2A and the corresponding first or second master CPU 11B, 12B of the second control device 2B is switched. Only the fixed-cycle frames output from the first or second master CPU 11B, 12B of the second control device 2B switched to the main system are transmitted on the corresponding A-system or B-system networks 3A, 3B. Will be.

  Further, in this remote I / O system 1, a link down occurs in any of the slaves (first to fourth media converters 20A to 25A, 20B to 25B and I / O slaves 30A and 30B) due to a failure or cable disconnection. When communication with an adjacent slave becomes impossible, a loopback process for transferring the received fixed-cycle frame to the transmission source is performed in a normal slave connected to the slave in which the link down has occurred.

  Then, the first or second master CPU 11A, 11B, 12A, 12B of the first and second control devices 2A, 2B set to the main system performs all of the loops on the networks 3A, 3B. When the fixed-cycle frame returns without being transmitted to the slave, each of the networks 3A and 3B on the second switching hubs 21A and 21B in addition to the first switching hubs 20A and 20B is thereafter transmitted. Sends a periodic frame with the slave as the destination.

  As a result, fixed-cycle frames are transmitted from both ends of the ring-type networks 3A and 3B, respectively, and these fixed-cycle frames are looped back by the link-down slave or the normal slave connected to the disconnected cable. The data is transferred to the first master CPUs 11A and 12A or the second master CPUs 11B and 12B of the first and second control devices 2A and 2B via the original route.

  As described above, in this remote I / O system 1, even when a link down occurs in any of the slaves constituting the A-system and B-system networks 3A and 3B, it is defined in the Ethernet (registered trademark) standard. By using the loopback function, it is possible to ensure communication between the slaves other than the slave in which the link down has occurred and the first and second control devices 2A and 2B.

  2A to 2E show the frame formats of the fixed-cycle frames output from the first master CPUs 11A and 11B and the second master CPUs 12A and 12B of the first or second control devices 2A and 2B. Show.

  As shown in FIG. 2A, the periodic frame is composed of a 14-byte Ethernet (registered trademark) header field (Ethernet (registered trademark) Header) and a maximum 1500-byte Ethernet (registered trademark) data field (Ethernet (registered trademark)). (Trademark) Data) and a 4-byte FCS (Frame Check Sequence) field (FCS). The Ethernet (registered trademark) header field stores the destination of the fixed-cycle frame and the address of the transmission source, and the FCS field contains information for checking the error of the fixed-cycle frame such as a CRC (Cyclic Redundancy Check) code. Stored.

  As shown in FIG. 2B, the Ethernet (registered trademark) data field includes an 11-bit data length field (Length), a 1-bit reserve field (Reserve), and a 4-bit type field (Ty). , 44 to 1498 bytes of Ethercat Datagram field (1... N EtherCAT Datagrams). In the Ethercat datagram field, as shown in FIG. 2 (C), one or a plurality of Ethercat frames (hereinafter referred to as “Ethercat”) respectively associated with each slave to be transmitted of the fixed-cycle frame. The data length field stores the total data length of all the Ethercat datagrams stored in the Ethercat datagram field. In addition, a flag that is normally set to “0” is stored in the reserve field, and a code (“0x1” in the case of Ethercat) indicating the type of data stored in the Ethercat datagram field is stored in the type field. Is done.

  As shown in FIG. 2D, each Ethercat datagram field includes a 10-byte datagram header field (Datagram Header), a maximum 1486-byte data field (Data), and a 2-byte WKC (Working Counter). It consists of fields. In the data field, data transmitted to the corresponding slave by the master (the first master CPU 11A, 11B or the second master CPU 12A, 12B of the first or second control device 2A, 2B) (this embodiment) The above-mentioned control information) or the data that the slave should transmit to the master (the above-described sensor information in the present embodiment) is stored. Further, the WKC field stores a count value corresponding to the number of processes normally processed by the Ethercat datagram.

  Further, as shown in FIG. 2E, the datagram header field includes an 8-bit command field (Cmd), an 8-bit index field (Idx), a 32-bit address field (Address), and an 11-bit address field. Data type field (Len), 3-bit reserved field (R), 1-bit cyclic presence / absence bit field (C), 1-bit continuation presence / absence bit field (M), and 16-bit Ethercat interrupt request register Field (IRQ).

  The command field stores a code indicating the command type of the Ethercat command issued by the master to the corresponding slave, and the index field contains data to be transmitted from the master to the slave or information to be transmitted from the slave to the master. An index number representing the order of the data in the case of being divided and stored in a plurality of fixed-cycle frames is stored. The address field stores the address of the corresponding slave, and the data type field stores the data type of the datagram following the datagram header.

  Further, a flag indicating whether or not the fixed-cycle frame is already circulating through the corresponding slave is stored in the cycle presence / absence bit field. This flag is set to “0” when the fixed-cycle frame does not circulate through the corresponding slave, and when the fixed-cycle frame is already circulated through the corresponding slave, It is updated to “1”.

  The continuation presence / absence bit field stores a flag indicating whether or not the datagram is the last datagram stored in the Ethercat datagram field (FIG. 2B) of the fixed-cycle frame. This flag is set to “0” if the EtherCat datagram is the last EtherCat datagram stored in the EtherCat datagram field of the periodic frame, and is not the last EtherCat datagram. Is set to “1”. Further, the Ethercat interrupt request register field is used as a register for storing an interrupt request.

(2) Configuration of First and Second Switching Hubs FIG. 3 shows a specific configuration of the first switching hubs 20A and 20B and the second switching hubs 21A and 21B according to the present embodiment. As apparent from FIG. 3, the first switching hubs 20A and 20B and the second switching hubs 21A and 21B include the first to fourth PHYs 40A to 40B, the Ethercat (registered trademark) slave controller 41, The first and second PHYs 40A and 40B and the EtherCAT (registered trademark) slave controller 41 are connected to each other.

  The first to fourth PHYs 40A to 40D have a fixed period between the first and second control devices 2A and 2B and between the first media converters 22A and 22B or the fourth media converters 25A and 25B. It is a transmitting / receiving device that transmits and receives frames. In the case of the first switching hubs 20A and 20B, the first PHY 40A is the first controller 2A, the second PHY 40B is the second controller 2B, the third PHY 40C is the first media converter 22A, 22B, the second PHY 40D is connected to a communication monitoring device, and in the case of the second switching hubs 21A and 21B, the first PHY 40A is the first control device 2A, the second PHY 40B is the second control device 2B, and the third The PHY 40C is connected to the fourth media converters 25A and 25B, and the fourth PHY 40D is connected to a communication monitor device.

  The first to fourth PHYs 40A to 40D are each provided with a link signal output terminal, and the link signal output terminals of the first and second PHYs 40A and 40B are respectively the first or second of the AND circuit 43. The signal output terminal of the AND circuit 43 is connected to the first link signal input terminal of the Ethercat (registered trademark) slave controller 41 while being connected to the signal input terminal. The link signal output terminal of the third PHY 40C is connected to the second link signal input terminal of the Ethercat (registered trademark) slave controller 41.

  When the first and second PHYs 40A and 40B have a link with the connection destination first or second control device 2A or 2B (the connection destination first or second control device 2A, 2B), a link signal having a logic “1” level is transmitted to the AND circuit 43 via the link signal output terminal, while the connection with the connected first or second control device 2A, 2B is performed. When the link is disconnected (communication with the first or second control device 2A or 2B to be connected becomes impossible), the signal level of the link signal is switched to the logic “0” level.

  Further, the third PHY 40C has a link with the first media converters 22A and 22B or the fourth media converters 25A and 25B as connection destinations (the first media converters 22A and 22B as connection destinations). Or the fourth media converter 25A, 25B), a link signal having a logic “1” level is transmitted to the Ethercat (registered trademark) slave controller 41 via the link signal output terminal, while the connection destination The first media converter 22A, 22B or the fourth media converter 25A, 25B is disconnected (cannot communicate with the connected first media converter 22A, 22B or the fourth media converter 25A, 25B) In this case, the signal level of the link signal is switched to the logic “0” level.

  The Ethercat (registered trademark) slave controller 41 is a slave controller compliant with the Ethercat (registered trademark) standard as described above, and includes the first or second control device 2A, 2B and the slave (first media converter). 22A, 22B or the fourth media converter 25A, 25B) for performing communication according to the Ethercat (registered trademark) protocol. The Ethercat (registered trademark) slave controller 41 is equipped with various functions such as a loopback function defined by the Ethernet (registered trademark) standard.

  For example, the Ethercat (registered trademark) slave controller 41 is configured when the signal level of the link signal supplied from the AND circuit 43 to the first link signal input terminal becomes the logic “0” level (that is, the first control). In the case where at least one of the link between the device 2A and the first PHY 40A and the link between the second control device 2B and the second PHY 40B is disconnected), after that, the constant input through the third PHY 40C is performed. A loopback process is performed in which the periodic frame is turned back and sent back to the first media converter 22A, 22B or the fourth media converter 25A, 25B.

  Further, the Ethercat (registered trademark) slave controller 41 is configured such that the signal level of the link signal given from the third PHY 40C to the second link signal input terminal becomes a logic “0” level (that is, the third PHY 40C). And the first media converters 22A and 22B or the fourth media converters 25A and 25B are disconnected), then a fixed-cycle frame that is input via the first or second PHYs 40A and 40B. Is looped back and sent back to the first or second control device 2A, 2B as the transmission source.

  The branch connection unit 42 converts the fixed-cycle frame given from the first or second control device 2A, 2B to the first or second PHY 40A, 40B with the other second or first PHY 40B, 40A and the Ethercat ( Registered to the slave controller 41, and the fixed-cycle frame given to the third PHY 40C from the connected slave (first media converter 22A22B or fourth media converter 25A, 25B) is an Ethercat (registered trademark). ) MII (Media Independent) for connecting between the first and second PHYs 40A and 40B and the Ethercat (registered trademark) slave controller 41 so as to be distributed to the first and second PHYs 40A and 40B via the slave controller 41, respectively. Interface). The branch connection unit 42 includes first to fourth selector units 44A to 44D.

  In the first selector unit 44A, the first signal input terminal is connected to the signal output terminal of the first PHY 40A, and the second signal input terminal is connected to the signal output terminal of the second PHY 40B. . The signal output terminal of the first selector unit 44A is connected to the import-side reception port of the Ethercat (registered trademark) slave controller 41.

  The second selector unit 44B has a first signal input terminal connected to the import-side transmission port of the Ethercat (registered trademark) slave controller 41, and a second signal input terminal connected to the first selector unit. The signal output terminal of the second PHY 40B is connected together with the second signal input terminal of 44A. The signal output terminal of the second selector unit 44B is connected to the signal input terminal of the first PHY 40A.

  The third selector unit 44C has a first signal input terminal connected to a signal output terminal of the first PHY 40A together with a first signal input terminal of the first selector unit 44A, and a second signal input terminal Along with the first signal input terminal of the second selector unit 44B, it is connected to the transmission port on the import side of the Ethercat (registered trademark) slave controller 41. The signal output terminal of the third selector unit 44C is connected to the signal input terminal of the second PHY 40B.

  The fourth selector section 44D has a first signal input terminal connected to the signal output terminal of the first selector section 44A, and a second signal input terminal connected to the first signal of the second selector section 44B. Together with the input terminal and the second signal input terminal of the third selector section 44C, it is connected to the transmission port on the import side of the Ethercat (registered trademark) slave controller 41. The signal output terminal of the fourth selector unit 44D is connected to the signal input terminal of the fourth PHY 40D.

  The output port side of the Ethercat (registered trademark) slave controller 41 is connected to the signal output terminal of the third PHY 40C via the MII interface, and the signal output terminal is connected to the signal input terminal of the third PHY 40C. As a result, the Ethercat (registered trademark) slave controller 41 and the third PHY 40C can communicate bidirectionally.

FIG. 4 shows a specific configuration of the first to fourth selector units 44A to 44D. As is apparent from FIG. 4, first to fourth selector unit 44A~44D the first buffer memory 50A which is provided corresponding to the first signal input terminal 44IP _1, the first data management 51A, first read control unit 52A, second buffer memory 50B provided corresponding to _second signal input terminal 44IP2, _second data management unit 51B, and second read control unit 52B And a selector circuit 53 and an output arbitration control unit 54.

The first buffer memory 50A is a memory for temporarily storing (buffering) a fixed-cycle frame given to the _first signal input terminal 44IP1, for example, FIFO (First-In, First-Out). Consists of memory.

  The first data management unit 51A includes a counter function that counts the number of fixed-cycle frames stored in the first buffer memory 50A and the number of data (number of words) for each fixed-cycle frame. The first data management unit 51A, among the fixed-cycle frames stored in the first buffer memory 50A, the fixed-cycle frame with the oldest time stored in the first buffer memory 50A (hereinafter referred to as the highest frame). The first read control unit 52A is notified (disclosed) of the number of frames (referred to as an old fixed period frame).

  The first read control unit 52A is a memory controller that controls reading of a fixed-cycle frame stored in the first buffer memory 50A. When the fixed cycle frame is stored in the first buffer memory 50A, the first read control unit 52A requests the output arbitration control unit 54 to grant an output right that is a read permission of the fixed cycle frame. When the output right is given from the output arbitration control unit 54, the first read control unit 52A controls the first buffer memory 50A to output the oldest fixed cycle frame. Further, when the output of one fixed-cycle frame from the first buffer memory 50A is completed, the first read control unit 52A transmits a frame output completion notification to the output arbitration control unit 54.

On the other hand, the second buffer memory 50B is a memory for buffering a fixed-cycle frame given to the _second signal input terminal 44IP2, and is composed of, for example, a FIFO memory, like the first buffer memory 50A. Is done.

  The second data management unit 51B includes a counter function that counts the number of fixed-cycle frames stored in the second buffer memory 50B and the number of data of the fixed-cycle frames. The second data management unit 51B notifies (discloses) to the second read control unit 52B the number of frames of the oldest fixed cycle frame among the fixed cycle frames stored in the second buffer memory 50B.

  The second read control unit 52B is a memory controller that controls reading of the fixed-cycle frame stored in the second buffer memory 50B. When the fixed cycle frame is stored in the second buffer memory 50B, the second read control unit 52B requests the output arbitration control unit 54 to grant the right to output the fixed cycle frame. Then, when the output right is given from the output arbitration control unit 54, the second read control unit 52B controls the second buffer memory 50B to output the oldest fixed cycle frame. Further, when the output of the oldest fixed period frame from the second buffer memory 50B is completed, the second read control unit 52B transmits a frame output completion notification to the output arbitration control unit 54.

  In the selector circuit 53, the first signal input terminal is connected to the first buffer memory 50A, the second signal input terminal is connected to the second buffer memory 50B, and the signal output terminal is the first mounting destination. To signal output terminals 44OP of the fourth selector sections 44A to 44D. The selector circuit 53 selects one first or second signal input end designated by the output arbitration control unit 54 from the first and second signal input ends, and inputs the first or second signal input. A fixed-cycle frame given to the end is selectively output.

  The output arbitration control unit 54 prevents the first and second periodic frames stored in the first buffer memory 50A and the second periodic memory stored in the second buffer memory 50B from being output simultaneously. The buffer memory 50A has a function of controlling the readout timing of the fixed-cycle frames respectively stored in 50B, and the above-mentioned output right is granted in response to a request from the first or second read control unit 52A, 52B. The first or second read control unit 52A, 52B is given. The output arbitration control unit 54, when an output right grant request is given from both the first and second read control units 52A and 52B, the first or second read control unit 52A and 52B that has requested earlier. Grant output rights to. Also, when the output arbitration control unit 54 grants the output right to the first read control unit 52A, the output arbitration control unit 54 controls the selector circuit 53 to output a fixed-cycle frame that is input to the first signal input terminal. When an output right is given to the second read control unit 52B, a fixed-cycle frame input to the second signal input terminal is output.

In the first to fourth selector sections 44A to 44D having such a configuration, the frame data of the fixed-cycle frame given to the first or second signal input terminal 44IP ₁ or 44IP ₂ is the first or second frame data. the first or second buffer memory 50A connected to the signal input end 44IP _1, 44IP _2, is stored in 50B.

At this time, the first or second data management unit 51A or 51B connected to the first or second signal input terminal 44IP ₁ or 44IP ₂ has the frame data of the fixed period frame stored in the first or second buffer memory. A counter that counts the number of fixed-cycle frames stored in the first or second buffer memory 50A or 50B at the timing when writing to 50A or 50B is started (hereinafter referred to as a fixed-cycle frame counter). The counter value is incremented (counted up by “1”) and the number of data in the fixed-cycle frame is associated with the fixed-cycle frame (hereinafter referred to as a data number counter). Count by. When the first or second data management unit 51A or 51B completes the writing of the fixed-cycle frame to the first or second buffer memory 50A or 50B, the first or second data management unit 51A or 51B ends the count process and the next fixed-cycle frame. Wait for input.

  The first and second data management units 51A and 51B then associate with the oldest fixed cycle frame among the fixed cycle frames stored in the corresponding first or second buffer memory 50A or 50B. The count value of the data number counter is notified (disclosed) to the corresponding first or second read control unit 52A, 52B.

  When the count value of the data counter of the oldest fixed period frame notified from the corresponding first or second data management unit 51A or 51B is not “0”, the first and second read control units 52A and 52B The output arbitration control unit 54 is requested to grant the output right.

  When an output right grant request is given from the first or second read control unit 52A, 52B, the output arbitration control unit 54 grants an output right to the other second or first read control unit 52B, 52A. If not, the output right is granted to the first or second read control unit 52A, 52B that has requested the grant of the output right. In addition, the output arbitration control unit 54 controls the selector circuit 53 so as to select the signal output terminal corresponding to the first or second read control unit 52A, 52B to which the output right is given at that time.

  Then, the first or second read control unit 52A, 52B to which the output right is given from the output arbitration control unit 54 controls the corresponding first or second buffer memory 50A, 50B, so that the oldest fixed period Start frame data output. As a result, the data of the oldest fixed period frame is continuously output in units of words from the corresponding first or second buffer memory 50A, 50B, and this data is transmitted through the selector circuit 53 and the signal output terminal 44OP. 1 to the fourth selectors 44A to 44D.

  At this time, each time the first or second read control unit 52A or 52B outputs the data of the oldest fixed period frame from the corresponding first or second buffer memory 50A or 50B by one word, A read notification is transmitted to the first or second data management unit 51A or 51B. Each time the first or second data management unit 51A or 51B receives a read notification from the corresponding first or second read control unit 52A or 52B, the data number counter associated with the oldest fixed period frame is used. Is decremented (counts down by “1”).

  Then, the first or second read control unit 52A, 52B is read from the corresponding first or second buffer memory 50A, 50B, which is notified from the first or second data management unit 51A, 51B before long. When the count value of the data number counter of the oldest fixed period frame becomes “0”, reading of data from the first or second buffer memory 50A, 50B is stopped, and the frame for the output arbitration control unit 54 is stopped. Send output completion notification.

  In addition, when the count value of the data number counter associated with the oldest fixed period frame becomes “0”, the first or second data management unit 51A or 51B thereafter performs the corresponding first or second data management unit 51A or 51B. When other fixed cycle frames are stored in the buffer memories 50A and 50B, the first or second read control unit 52A or 52B corresponding to the count value of the data number counter associated with the fixed cycle frame is stored. When the fixed-cycle frame is not stored in the first or second buffer memory 50A, 50B, the first or second read control corresponding to “0” as it is as the count value of the frame number counter. Continue to notify the units 52A and 52B.

As described above, the first to fourth selector sections 44A to 44D buffer the fixed-cycle frames given to the first and second signal input terminals 44IP ₁ and 44IP ₂ as necessary. However, the signals are sequentially output from the signal output terminals 44OP of the first to fourth selector sections 44A to 44D.

  The state transition of the output arbitration control unit 54 in the first to fourth selector units 44A to 44D is shown in FIG. As shown in FIG. 5, the output arbitration control unit 54 has first to fifth states ST1 to ST5.

  The first state ST1 is a state where no output right is given to any of the first and second read control units 52A and 52B. Further, the second state ST2 is a state in which a frame output completion notification is not received from the first read control unit 52A after the output right is given to the first read control unit 52A. ST3 is a state in which a frame output completion notification is not received from the second read control unit 52B after the output right is given to the second read control unit 52B. Further, the fourth state ST4 is a state where the output right is granted to the first read control unit 52A and the grant of the output right to the second read control unit 52B is suspended, and the fifth state ST5 is In this state, the output right is given to the second read control unit 52B, and the grant of the output right to the first read control unit 52A is suspended.

  When the output arbitration control unit 54 is in the first state ST1 and receives an output right grant request from the first read control unit 52A, the output arbitration control unit 54 outputs the output right to the first read control unit 52A. Is assigned to the second state ST2, and when an output right grant request is given from the second read control unit 52B, the output right is given to the second read control unit 52B. To transit to the third state ST3. When the output arbitration control unit 54 receives the frame output completion notification from the first or second read control unit 52A or 52B to which the output right is granted in the second or third state ST2 or ST3, Return to state 1 ST1.

  On the other hand, the output arbitration control unit 54 is different from the first or second read control unit 52A, 52B to which the output right is given in the second or third state ST2, ST3. When an output right grant request is given from one read control unit 52B, 52A, the state transits to the fourth or fifth state ST4, ST5. Then, in the case of the fourth or fifth state ST4 or ST5, the output arbitration control unit 54 sends a frame output completion notification from the first or second read control unit 52A or 52B to which the output right has been given in advance. When received, the output right held at that time is given to the second or first read control unit 52B, 52A, thereby making a transition to the third or second state ST3, ST2.

  After that, the output arbitration control unit 54 sequentially switches the state in the same manner as described above based on the output right grant request or the frame output completion notification from the first or second read control unit 52A, 52B. In response to a request from the first or second read control unit 52A, 52B, an output right is given to the first or second read control unit 52A, 52B.

(3) Data Flow of Fixed Period Frames in First and Second Switching Hubs Next, a flow of data of fixed period frames in the first switching hubs 20A and 20B and the second switching hubs 21A and 21B is shown in FIG. Description will be made with reference to FIG. 7 to 9, “ESC” represents an Ethercat (registered trademark) slave controller 41, and “S1” to “S4” represent the first switching hub 20A and the second switching hub 21A, respectively. 21B shows first to fourth selector sections 44A to 44D.

  First, when the first control device 2A is set as the main system, the fixed-cycle frame output from the first control device 2A passes through the first PHY 40A of the first switching hubs 20A and 20B. The first selector unit 44A and the third selector unit 44C are given to the first buffer memory 50A of the first selector unit 44A and the first buffer memory 50A of the third selector unit 44C temporarily. (SP1 and SP2 in FIG. 7). The fixed-cycle frame stored in the first buffer memory 50A of the third selector unit 44C is then read from the first buffer memory 50A and given to the second PHY 40B. It is transmitted to the second control device 2B via the PHY 40B (SP3, SP4 in FIG. 7).

  The fixed-cycle frame stored in the first buffer memory 50A of the first selector unit 44A is then read out from the first buffer memory 50A and the Ethercat (registered trademark) slave controller 41 and the fourth To the selector unit 44D (SP6, SP7 in FIG. 7).

  Then, the fixed period frame given to the Ethercat (registered trademark) slave controller 41 is not subjected to any processing in the Ethercat (registered trademark) slave controller 41 (that is, the Ethercat (registered trademark)). ) It is given to the third PHY 40C (through the slave controller 41), and the next slave (via the third PHY 40C, the first media converters 22A, 22B in the case of the first switching hubs 20A, 20B) In the case of the second switching hub 21A, 21B, it is transmitted to the fourth media converter 25A, 25B) (SP8, SP9 in FIG. 7).

  The fixed-cycle frame given to the fourth selector unit 44D is temporarily stored in the first buffer memory 50A of the fourth selector unit 44D and then read out from the first buffer memory 50A. 4 is transmitted to the communication monitoring device 60 via the fourth PHY 40D (SP10 and SP11 in FIG. 7).

  On the other hand, when the second control device 2B is set as the main system, the fixed-cycle frame output from the second control device 2B passes through the second PHY 40B of the first switching hubs 20A and 20B. It is given to the first selector unit 44A and the second selector unit 44B, and temporarily sent to the second buffer memory 50B of the first selector unit 44A and the second buffer memory 50B of the second selector unit 44B. (SP20, SP21 in FIG. 8).

  The fixed-cycle frame stored in the second buffer memory 50B of the second selector unit 44B is then read from the second buffer memory 50B and given to the first PHY 40A. It is transmitted to the first control device 2A via the PHY 40A (SP22, SP23 in FIG. 8).

  The fixed-cycle frame stored in the second buffer memory 50B of the first selector unit 44A is thereafter read out from the second buffer memory 50B, and the Ethercat (registered trademark) slave controller 41 and the fourth To the selector unit 44D (SP25, SP26 in FIG. 8).

  Then, the fixed-cycle frame given to the Ethercat (registered trademark) slave controller 41 is subsequently transferred to the next-stage slave through the Ethercat (registered trademark) slave controller 41 and the third PHY 40C in the same manner as described above. It is transmitted (SP27, SP28 in FIG. 8). Similarly to the above, the fixed-cycle frame given to the fourth selector unit 44D is temporarily stored in the first buffer memory 50A of the fourth selector unit 44D and then from the first buffer memory 50A. It is read out, given to the fourth PHY 40D, and transmitted to the communication monitor device 60 via the fourth PHY 40D (SP29, SP30 in FIG. 8).

  On the other hand, the first from the slave (first media converters 22A and 22B in the case of the first switching hubs 20A and 20B, and fourth media converters 25A and 25B in the case of the second switching hubs 21A and 21B). The periodic frame transmitted to the switching hub 20A, 20B or the second switching hub 21A, 21B is transmitted to the receiving port on the outport side of the Ethercat (registered trademark) slave controller 41 via the third PHY 40C. (SP40, SP41 in FIG. 9).

  Thereafter, the fixed period frame is given to the second to fourth selector units 44B to 44D without any processing in the Ethercat (registered trademark) slave controller 41, and the second selector unit 44B. The data is temporarily stored in the first buffer memory 50A, the second buffer memory 50B of the third selector unit 44C, and the second buffer memory 50B of the fourth selector unit 44D (SP42 to SP44 in FIG. 9). .

  The fixed-cycle frame stored in the first buffer memory 50A of the second selector unit 44B is then read from the first buffer memory 50A and given to the first PHY 40A. It is transmitted to the first control device 2A via the PHY 40A (SP45, SP46 in FIG. 9).

  The fixed-cycle frame stored in the second buffer memory 50B of the third selector unit 44C is then read from the second buffer memory 50B and given to the second PHY 40B. It is transmitted to the second control device 2B via the PHY 40B (SP47, SP48 in FIG. 9).

  Further, the fixed-cycle frame stored in the second buffer memory 50B of the fourth selector unit 44D is then read from the second buffer memory 50B and given to the fourth PHY 40D. It is transmitted to the communication monitoring device 60 via the PHY 40D (SP49, SP50 in FIG. 9).

  As described above, in the first switching hubs 20A and 20B and the second switching hubs 21A and 21B according to the present embodiment, the fixed-cycle frame input via any of the first to fourth PHYs 40A to 40D is The first switching hubs 20A, 20B or the second switching hubs 21A, 21B are distributed inside the first switching hubs 20A, 21B and all other first to fourth PHYs 40A to 40D, respectively. It can be transmitted to devices (first control device 2A, second control device 2B, slave, or communication monitoring device 60) connected to the second switching hubs 21A, 21B.

(4) Effects of the present embodiment As described above, in the remote I / O system 1 of the present embodiment, the first switching hubs 20A and 20B and the second switching hubs 21A and 21B have Ethercat (registered trademark). The slave controller 41 is mounted, and the first or second PHY 20A from the first or second control device 2A, 2B is provided inside the first switching hub 20A, 20B and the second switching hub 21A, 21B. The periodic frame given to 20B is distributed to the other second or first PHY 20B, 20A and the Ethercat (registered trademark) slave controller 41, and the first media converter 22A, 22B or the fourth media converter 25A. , 25B to the third PHY 40C, the periodic frame Between the first and second PHYs 40A and 40B and the Ethercat (registered trademark) slave controller 41 so that they can be distributed to the first and second PHYs 40A and 40B via the slave (registered trademark) slave controller 41, respectively. Are connected by the branch connection unit 42, and therefore the functions such as the loopback function and the hot connect function defined in the Ethercat (registered trademark) standard are provided in the first switching hub 20A, 20B and the second switching hub 20A, 20B. The switching hubs 21A and 21B can be provided.

  Therefore, for example, between the first switching hub 20A, 20B or the second switching hub 21A, 21B and the first or second control device 2A, 2B, or the first switching hub 20A, 20B or the second switching. Even when the link between the hub 21A, 21B and the first media converter 22A, 22B or the fourth media converter 25A, 25B is disconnected, the corresponding first switching hub 20A, 20B or second switching is performed. Since the loopback process is executed in the hubs 21A and 21B, it is possible to prevent the occurrence of problems such as the disappearance of the fixed-cycle frame at the link disconnection point.

  Thus, according to the first switching hubs 20A and 20B and the second switching hubs 21A and 21B of the present embodiment, a highly reliable remote I / O system 1 can be realized.

(5) Other Embodiments In the above-described embodiment, a case has been described in which two control devices (first and second control devices 2A and 2B) as master devices are provided by redundancy. However, the present invention is not limited to this, and for example, three or more control devices may be provided. In this case, the first switching hubs 20A and 20B and the second switching hubs 21A and 21B are provided with PHYs (hereinafter referred to as master side PHYs) corresponding to the respective control devices. A fixed-cycle frame given to one of the PHYs is distributed to all the other master-side PHYs and the Ethercat (registered trademark) slave controller, and given from the slave via the third PHY. May be constructed so that can be distributed to all the master-side PHYs.

  In the above-described embodiment, the case where the Ethercat (registered trademark) protocol is applied as the communication protocol of the remote I / O system 1 has been described. However, the present invention is not limited to this, and various other types can be used. The industrial protocol can be widely applied. In this case, a slave controller corresponding to the industrial communication protocol applied to the remote I / O system 1 may be mounted on the first switching hub 20A, 20B and the second switching hub 21A, 21B.

  Further, in the above-described embodiment, the present invention is applied to the first to fourth media converters 22A to 25A and 22B to 25B, the AI slaves 26A and 26B, the AO slaves 27A and 27B, the DI slaves 28A and 28B, and the DO slave. Although the case where 29A and 29B are applied to the remote I / O system 1 which is a slave device has been described, the present invention is not limited to this, and the slave device is widely applied to other remote I / O systems. be able to.

  Further, in the above-described embodiment, in the first switching hub 20A, 20B and the second switching hub 21A, 21B, between the first control device 2A corresponding to the first PHY 40A and the first PHY 40A. The AND circuit 43 is applied as a monitoring unit that monitors whether or not the link between the second PHY 40B and the link between the second control device 2B corresponding to the second PHY 40B is secured. Although the case has been described, the present invention is not limited to this, and various other devices can be applied as the monitoring unit.

  The present invention relates to various communication distribution devices for connecting at least two master devices and a network to which one or more slave devices are connected in a remote I / O system to which a master-slave industrial communication protocol is applied. Can be widely applied to.

DESCRIPTION OF SYMBOLS 1 ... Remote I / O system, 2A, 2B ... Control apparatus, 3A, 3B ... Network, 4 ... Master-slave switcher, 10A, 10B ... Main CPU, 11A, 11B, 12A, 12B ... Master CPU , 20A, 20B, 21A, 21B ... Switching hub, 22A-25A, 22B-25B ... Media converter, 26A, 26B ... AI slave, 27A, 27B ... AO slave, 28A, 28B ... DI slave, 29A , 29B... DO slave, 30A, 30B... I / O slave, 31... Signal distributor, 40A to 40D... PHY, 41 ... Ethercat (registered trademark) slave controller, 42. 43... AND circuit, 44A to 44D... Selector section, 50A and 50B... Buffer memory, 51A and 5 B ...... data management unit, 52A, 52B ...... read control unit, 53 ...... selector circuit, 54 ...... output arbitration control unit, equipment 60 ...... communication monitor.

Claims (7)

In a remote I / O system to which a master-slave industrial communication protocol is applied, a communication distribution device that connects at least two master devices and a network to which one or more slave devices are connected,
First and second transmission / reception units that are provided corresponding to the respective master devices and transmit / receive communication frames to / from the corresponding master devices;
A third transmission / reception unit connected to the network and transmitting / receiving the communication frame to / from the slave device via the network;
A slave controller connected so as to be capable of bidirectional communication with the third transmission / reception unit, and performing communication processing for performing communication according to the industrial communication protocol with the master device or the slave device;
Distributing the communication frame given to one of the corresponding first or second transmission / reception units from any one of the master devices to the other second or first transmission / reception unit and the slave controller, and connecting Each of the first and second transmission / reception units distributes the communication frame given from the slave device to the third transmission / reception unit to the first and second transmission / reception units via the slave controller. And a branch connection unit for connecting the slave controller to the slave controller. The industrial communication protocol is an Ethercat (registered trademark) protocol,
The communication distribution device according to claim 1, wherein the slave controller is a slave controller that conforms to the Ethercat (registered trademark) standard. The branch connection is
Including at least first to third selector units;
The first selector unit includes:
The first signal input terminal is connected to the signal output terminal of the first transmission / reception unit, the second signal input terminal is connected to the signal input terminal of the second transmission / reception unit, and the signal output terminal is Connected to the receiving port on the import side of the slave controller,
The second selector unit includes:
The first signal input terminal is connected to the import-side transmission port of the slave controller, and the second signal input terminal together with the second signal input terminal of the first selector unit is the second transmission / reception And a signal output terminal is connected to a signal input terminal of the first transmission / reception unit,
The third selector unit includes:
The first signal input terminal is connected to the signal output terminal of the first transmitting / receiving unit together with the first signal input terminal of the first selector unit, and the second signal input terminal is connected to the second selector. The first signal input terminal of the unit is connected to the transmission port on the import side of the slave controller, and the signal output terminal is connected to the signal input terminal of the third transmission / reception unit. Item 4. The communication distribution device according to Item 1. The first to third selector units are
A first buffer memory connected to the first signal input terminal and temporarily storing a communication frame given to the first signal input terminal;
A second buffer memory connected to the second signal input terminal and temporarily storing a communication frame given to the first signal input terminal;
The communication frames stored in the first buffer memory and the communication frames stored in the second buffer memory are stored in the first and second buffer memories so as not to be output simultaneously. The communication distribution device according to claim 3, further comprising: an output arbitration control unit that controls a reading timing of the communication frame. A fourth transmission / reception unit connected to a communication monitoring device for monitoring communication;
The branch connection unit includes a fourth selector unit,
The fourth selector unit includes:
A first signal input terminal is connected to the signal output terminal of the first selector unit, and a second signal input terminal is connected to the first signal input terminal and the third signal terminal of the second selector unit. The second signal input terminal of the selector unit is connected to the transmission port on the import side of the slave controller, and the signal output terminal is connected to the signal input terminal of the fourth transmission / reception unit. Item 4. The communication distribution device according to Item 3. A link between the first transmission / reception unit and the master device corresponding to the first transmission / reception unit and a link between the second transmission / reception unit and the master device corresponding to the second transmission / reception unit are respectively secured. A monitoring unit that monitors whether or not
The monitoring unit
Either the link between the master devices corresponding to the first transmission / reception unit and the first transmission / reception unit, or the link between the master devices corresponding to the second transmission / reception unit and the second transmission / reception unit If one is disconnected, notify the slave controller of the disconnection,
The slave controller is
When the disconnection is notified from the monitoring unit, the communication frame given from the slave device to the third transmission / reception unit via the network is sent back to the slave device as a transmission source. The communication distribution device according to claim 1. The third transmission / reception unit includes:
When the link with the slave device connected via the network is disconnected, the slave controller is notified of the disconnection,
The slave controller is
When the disconnection is notified from the third transmission / reception unit, the communication frame given from the master device to the first or second transmission / reception unit is sent back to the transmission source master device. The communication distribution device according to claim 1.

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