WO2015159320A1

WO2015159320A1 - Protocol conversion apparatus and industrial network system

Info

Publication number: WO2015159320A1
Application number: PCT/JP2014/002152
Authority: WO
Inventors: 暁楠時
Original assignee: 三菱電機株式会社
Priority date: 2014-04-16
Filing date: 2014-04-16
Publication date: 2015-10-22
Also published as: TW201541914A

Abstract

A protocol conversion apparatus (100) comprises: a protocol conversion unit (3) that converts a frame, which includes either a request received via a first interface (A103) or a direct request that is a request to be processed on a priority basis, to a frame suitable for a second network (B104) and that also converts a frame, which is of a response received via a second interface and responsive to the request or to the direct request, to a frame suitable for a first network (A103); and an output control unit (4) that selects, in accordance with whether or not the response is received from the second network (B104) and whether or not the direct request is received from the first network (A103), a frame to be outputted to the second interface (2) and that also selects, in accordance with whether or not a direct request is received from the second network (B104), a frame to be outputted to the first interface (1). Therefore, even in a case of causing networks having different protocols to perform relaying, the protocol conversion apparatus can process, on a priority basis, preferred data that require synchronism.

Description

Protocol converter and industrial network system

This invention relates to a protocol converter.

In a field called an industrial network, there are a connection type and a connectionless type as a communication method between a master and a slave. A connection type communication method performs communication with a 1: 1 relationship between a request and a response after opening a connection. Among the connection-type communications, there are a normal type in which requests and responses between a master and a slave are alternated, and a pipeline type in which a plurality of requests are sent continuously and a plurality of responses are received at once (see Patent Document 1). .

Further, not only industrial networks, but also protocol conversion devices for relaying different network protocols generally exist (see Patent Document 2).

JP 2004-88382 A JP 2001-7839 A

There are various types of networks in the field called industrial networks, and there are networks that can handle both the connection type and connectionless type described above, and the connection type as well as the normal type and pipeline type. Some networks can only handle the normal type of connection. When relaying between a network that supports all types and a network that supports only the connection-type normal type by protocol conversion, it is necessary to match only the normal type when relaying.

When performing such relaying, normal protocol conversion devices convert frames and packets using the first-in first-out method, so it is not possible to handle industrial networks that require strong synchronization with priority data. There was a problem.

The present invention has been made in view of such a situation, and realizes a protocol converter capable of preferentially processing priority data requiring synchronization even when relaying networks having different protocols. With the goal.

In order to solve the above-described problems and achieve the object, the present invention provides a first protocol that alternately performs a request and a response to the request, and a second protocol that sends a plurality of requests without waiting for a response to the request. The first interface connected to the first network corresponding to both of the above and the second interface connected to the second network corresponding to only the first protocol and transmitted and received the frame. A frame including a direct request which is a request received at the first interface or a request to be preferentially processed is converted into a frame suitable for the second network, and the request or direct request received at the second interface is converted. A protocol converter for converting the response frame into a frame suitable for the first network; A frame to be output to the second interface is selected according to whether or not a response is received from the second network and whether or not there is a direct request from the first network. And an output control unit that selects a frame to be output to one interface.

Since the apparatus according to the present invention has the above-described configuration, even if a network having a different protocol is relayed, there is an effect that priority data requiring synchronization can be preferentially processed.

FIG. 3 shows a gateway device 100 in the equipment network in the first embodiment. The figure which showed the request and response about the normal type of connection type communication, a pipeline type, and connectionless communication in time series. FIG. 4 is a diagram illustrating a sequence example in which the PLC 101 and the slave 102 in the first embodiment communicate via the protocol conversion device 100. The figure which shows the example of the sequence which the protocol converter 100 performs when the network A103 in Embodiment 1 performs the priority communication by a pipeline type communication and a direct request | requirement. The flowchart of operation | movement of the protocol converter 100 which operate | moves in the sequence of FIG. 1 is a configuration diagram of a protocol conversion device 100 according to Embodiment 1. FIG. The figure which shows the difference of the request | requirement frame in Embodiment 1 and Embodiment 2. FIG. The figure which shows the example of the sequence which the protocol converter 100 performs at the time of putting together several instruction | command from the network A103 in Embodiment 2 in one frame. The figure which shows the example of the sequence which the protocol converter 100 performs at the time of putting together several instruction | command from the network A103 in Embodiment 3 in one flame | frame. 10 is a flowchart of the operation of the protocol conversion apparatus 100 that operates in the sequence of FIG.

Hereinafter, embodiments of a protocol conversion apparatus and a protocol conversion method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing an example of an industrial network system having a protocol conversion apparatus according to the first embodiment.
The configuration will be described.

The network 103 between the PLC 101 and the protocol conversion apparatus 100 is a network (hereinafter referred to as a network A) that can handle all of the connection type, connectionless type, connection type, normal type, and pipeline type. In this embodiment, at least the connection type will be described. On the other hand, the network 104 between the protocol conversion apparatus 100 and the device 102 is a network that supports only a connection-type normal type (hereinafter referred to as network B).

In FIG. 1, a PLC (Programmable Logic Controller) 101 is connected to a device 102 via a protocol converter 100.
The PLC 101 issues a command to the device 102 and outputs information on the command to the network A103. The PLC 101 also receives response information output from the device 102 to the network A 103 via the network B 104 and the protocol converter 100.

The protocol conversion apparatus 100 receives the command information for the device 102 from the PLC 101 output to the network A 103, converts it, and outputs it to the network B 104 to which the device 102 is connected. Further, the protocol conversion apparatus 100 receives the response information for the PLC 101 from the device 102 output to the network B 104, converts it, and outputs it to the network A 103 to which the PLC 101 is connected.
The device 102 is connected to the network B 104, receives command information from the PLC 101, and outputs response information for the PLC 101.

Although FIG. 1 shows one PLC 101 and one protocol conversion device 100 connected to the network A, a plurality of PLCs may be provided. Further, although one protocol conversion device 100 and one device are connected to the network B, one protocol conversion device 100 is connected to one network B, but a plurality of devices 102 may be connected. .

FIG. 2 is a diagram showing, in time series, requests and responses for the normal type, pipeline type, and connectionless communication of the connection type communication described above.
The left side of FIG. 2 is a normal type of connection-type communication, in which requests of a master (corresponding to the PLC 101 in this embodiment) and responses of slaves (corresponding to the device 102 in this embodiment) are alternately performed.
The center of FIG. 2 shows a pipeline type of connection type communication. Regardless of whether there is a response from the master or from the slave, requests are transmitted at regular intervals, and the slave responds in the order received.
The right side of FIG. 2 shows connectionless communication, in which only transmission from the master to the slave is performed.

FIG. 3 is a diagram illustrating a sequence example in which the PLC 101 and the slave 102 communicate with each other via the protocol conversion apparatus 100 according to the first embodiment.
As described above, the network A103 between the PLC 101 and the protocol conversion apparatus 100 can cope with all types shown in FIG. 2, but the network B104 between the protocol conversion apparatus 100 and the slave 102 is connected to FIG. Only the normal type of connection-type communication on the left side of can be supported. Therefore, in the case of a normal protocol conversion device, frames and packets are converted by the first-in first-out method, so the network A 103 side also needs to be adapted to the normal type of connection-type communication. Also in this embodiment, When the network A 103 side is adapted to the normal type of connection type communication, the sequence shown in FIG. 3 is obtained.

Next, processing performed by the protocol conversion apparatus 100 for various communication types of the network A103 will be described.
FIG. 4 is a diagram illustrating an example of a sequence performed by the protocol conversion apparatus 100 when the network A 103 according to the first embodiment performs priority communication based on pipeline-type communication and a direct request.

In FIG. 4, first, the PLC 101 outputs a connection request to the device 102. The protocol conversion apparatus 100 received via the network A 103 converts the connection request into a protocol compatible with the network B 104 and transfers the connection request to the device 102. The device 102 outputs a connection request response to the PLC 101. The protocol conversion apparatus 100 converts the received connection request response into a protocol compatible with the network A103, and then sends a connection request response to the PLC 101 connected to the network A103. Perform response forwarding.

After the connection between the PLC 101 and the device 102 is established, the PLC 101 transmits the requests CI1 to CI3 (CI is an abbreviation of a control instruction, and a number is a control instruction number) to the device 102 in a connection type communication pipeline type. To do. Thereafter, it is assumed that the PLC 101 immediately transmits a direct request to the device 102 that needs priority control.

The protocol conversion apparatus 100 converts the received request CI1 so as to conform to the network B104, and then transfers it to the device 102.
Upon receiving the request CI1 response from the device 102, the protocol conversion apparatus 100 converts it so as to conform to the network A103, transfers it to the PLC 101, and converts the received request CI2 so as to conform to the network B104. Forward to.

The protocol conversion apparatus 100 receives the request CI3 and the direct request from the PLC 101 during the processing of the response of the request CI2 received from the device.
In that case, the protocol conversion apparatus 100 converts the direct request so as to conform to the network B 104 and then transfers the request to the device 102. Then, the protocol conversion apparatus 100 converts the response of the request CI2 received from the device so as to conform to the network A103, and then transfers it to the PLC101.

Next, the protocol conversion apparatus 100 converts the response of the direct request received from the device 102 so as to be compatible with the network A103, and after transferring the response to the PLC 101, converts the received request CI3 so as to be compatible with the network B104. After that, the data is transferred to the device 102. When the response of the request CI3 is received, the protocol conversion device 100 converts the request CI3 so as to conform to the network A103, and then transfers it to the PLC101.

Finally, upon receiving a connection end request from the PLC 101, the protocol conversion apparatus 100 converts the request to conform to the network B 104 and then transfers it to the device 102. Then, when receiving a response to the connection end request, the protocol conversion device 100 converts it to conform to the network A103 and then transfers it to the PLC 101, and the connection is ended.

Next, a flowchart of the operation of the protocol conversion apparatus 100 when the sequence of FIG. 4 is performed will be described.
FIG. 5 is a flowchart of the operation of the protocol conversion apparatus 100 operating in the sequence of FIG.

First, it is confirmed in step S501 that a connection (CONNECTION) has been established. If not established, it is processed as an error in step S514. If it has been established, the process proceeds to step S502 or step S508.
In step S502, a request from the PLC 101 is received. In FIG. 4, the requests CI1 to CI3 and the reception of the direct request are applicable.

In step S503, for each request, the protocol is converted so that the network A103 can be adapted to the network B104.
When converting the network to a different type, a conversion method for converting the header and actual data in the frame so that it can be interpreted on the network after passing through the protocol conversion device 100, There is an encapsulation method in which data in accordance with a network protocol is generated and the protocol conversion apparatus 100 converts only the frame header. In this embodiment, either is possible, but the conversion method will be described.

In step S504, the protocol conversion apparatus 100 determines whether a response is received from the device 102 via the network B 104. If NO, the operation of step S504 is repeated. This corresponds to the case where the response of the request CI2 is not received when the request CI3 in FIG. 4 is received. This is because the network B 104 is a normal connection type, and unless a response is received, the request cannot be transferred to the network B 104 side.

In step S504, after receiving the response (when the request CI2 response was received when the request CI3 in FIG. 4 was received), in step S505, the protocol conversion apparatus 100 determines whether or not the request has been received directly. Confirm. If a direct request has been received, in step S507, the protocol conversion apparatus 100 first transfers the direct request to the device 102 via the network B 104, and returns to step S504. Referring to FIG. 4, the protocol conversion apparatus 100 receives the request CI 3 and the direct request, receives the response of the request CI 2, and transfers the direct request to the device 102.

In step S505, if the protocol conversion apparatus 100 has not received a direct request, the request other than the direct request is transferred in step S506. In FIG. 4, the request CI 2 is transferred to the device 102 after receiving the request CI 2 from the PLC 101.

Next, in step S513, it is confirmed whether or not the connection (CONNECTION) is completed. If NO, the protocol conversion apparatus 100 continues the process. If YES, the process will end.

Next, the case of step S508 will be described. In step S508, the protocol conversion apparatus 100 receives a response to the request or direct request from the device 102. In step S509, the protocol conversion apparatus 100 converts the protocol so that the network B104 can be adapted to the network A103.

Next, when there is a response to the direct request in the response subjected to protocol conversion in step S510, the response to the direct request is transferred to the PLC 101 connected to the network A103 in step S511. If there is no response to the direct request in the response converted in step S510, the request response is transferred.

Finally, the configuration of the protocol conversion apparatus 100 will be described.
FIG. 6 is a configuration diagram of the protocol conversion apparatus 100 according to the first embodiment.
The first interface 1 receives a request from the PLC 101 connected via the network A 103 and transfers a response. In FIG. 5, this corresponds to S501, S511, and S512.
The second interface 2 in FIG. 6 transfers a request to the device 102 connected via the network B 104 and receives a response to the request from the device 102. In FIG. 5, this corresponds to S506, S507, and S508.

The protocol conversion unit 3 in FIG. 6 converts the request received from the first interface so as to conform to the network B 104 and outputs it to the output control unit 4. Further, the protocol conversion unit 3 converts the request received from the second interface so as to conform to the network A 103 and outputs the request to the output control unit 4. In FIG. 5, this corresponds to S503 and S509.
The output control unit 4 in FIG. 6 selects a frame to be output according to the presence / absence of reception of a response and the presence / absence of a direct request for a frame after protocol conversion suitable for the network B 104, and outputs the selected frame to the second interface. In FIG. 5, this corresponds to S504 and S505.
Further, the output control unit 4 in FIG. 6 selects a frame for outputting a frame after protocol conversion suitable for the network A 103 according to the presence / absence of a direct response request, and then outputs the frame to the second interface. FIG. 5 corresponds to S510.

Therefore, the protocol conversion apparatus 100 is connected to the first network A103 corresponding to both a protocol that alternately performs a request and a response to the request and a protocol that sequentially sends a plurality of requests without waiting for a response to the request. The first interface 1 that transmits and receives frames, the second interface 2 that is connected to the second network B104 that supports only the protocol that alternately performs requests and responses to requests, and that transmits and receives frames, and the first interface A frame including a direct request which is a request received in A103 or a request to be preferentially processed is converted into a frame suitable for the second network B104, and a frame received in response to the request or direct request received by the second interface is converted. For the first network A103 The protocol conversion unit 3 that converts the frame into a combined frame and the reception of a response from the second network B 104 and the direct request from the first network A 103 for the frame converted to be compatible with the second network B 104 A frame to be output to the second interface 2 is selected according to the presence / absence, and the first frame is selected according to the presence / absence of a direct request from the second network B 104 for the frame converted to be compatible with the first network A103. Since the output control unit 4 for selecting a frame to be output to the interface 1 is provided, priority data requiring synchronization can be preferentially processed even when a network having a different protocol is relayed.

Embodiment 2. FIG.
In the second embodiment, a case will be described in which all the configurations and operations of the first embodiment are provided and a plurality of requests are communicated in one frame in the network A103.

FIG. 7 is a diagram showing a difference between request frames in the first embodiment and the second embodiment. In the case of the first embodiment, as described on the upper side of FIG. 7, the description has been made on the assumption that only one control instruction (CI1) request is described for one frame and transmitted from the PLC 101. In the second embodiment, as shown in the lower part of FIG. 7, a case will be described in which requests for a plurality of control instructions (CI1 to CI4) are transmitted from the PLC 101 for one frame.

As shown in the lower part of FIG. 7, when a plurality of requests for control instructions (CI1 to CI4) are collected for one frame, the network A103 transmits and receives a plurality of commands in one frame. In the network B104, on the other hand, as in the first embodiment, one command is sent to the device as one request, and the response can be performed. is necessary.

Although the configuration itself of the protocol conversion apparatus 100 in the second embodiment is not changed from that in FIG. 6 of the first embodiment, the processing contents in the protocol conversion unit 3 and the output processing unit 4 are particularly different. Similarly, the flowchart showing the operation of the protocol conversion apparatus 100 is not different from that in FIG. 5 of the first embodiment, but there are different parts due to changes in the processing contents in the protocol conversion unit 3 and the output processing unit 4 and are different. Only the part will be described below.

With respect to the protocol conversion unit 3 in FIG. 6, in the present embodiment, the reception of the request in step S <b> 502 in FIG. 5 includes a plurality of instruction information in one frame, and therefore, step 503 corresponding to the operation of the protocol conversion unit 3. First, it is necessary to convert one frame received from the network A103 into a plurality of commands that are decomposed one by one and adapted to the network B104. Steps S504 to S507 are the same as those in the first embodiment.

Similarly, with respect to the protocol conversion unit 3 in FIG. 6, in this embodiment, for protocol conversion of responses to requests other than direct request responses in step S509 in FIG. In step 509 corresponding to the operation of the protocol conversion unit 3, a plurality of responses received from the network B 104 are bundled and converted into one frame so as to be compatible with the network A 103 and output to the control instruction unit 4. There is a need to.

In the present embodiment, the control instruction unit 4 in FIG. 6 is compared with a single response and a direct response in step S510 in FIG. 5 corresponding to the operation in the first embodiment. The mode is different in that it is performed by comparing one frame obtained by bundling a plurality of responses with a direct response. The rest is the same as in the first embodiment.

Next, a communication sequence of the protocol conversion apparatus 100 in this embodiment will be described. FIG. 8 is a diagram illustrating an example of a sequence performed by the protocol conversion apparatus 100 when a plurality of commands are collected into one frame from the network A 103 according to the second embodiment.

In FIG. 8, the connection (CONNECTION) establishment and connection termination steps shown in the first embodiment are the same as those in the first embodiment, and are therefore omitted.
After the connection between the PLC 101 and the device 102 is established, the PLC 101 aggregates the requests CI1 to CI3 (CI is an abbreviation for a control instruction, and a number is a control instruction number) into one frame as shown in the lower part of FIG. It transmits to the device 102 in the state. Thereafter, it is assumed that the PLC 101 immediately transmits a direct request to the device 102 that needs priority control.

The protocol conversion apparatus 100 extracts the received requests CI1 to CI3 one by one from the frame, converts them so as to be compatible with the network B104, and then transfers them from the request C1 to the device 102.
When receiving the response of the request CI 1 from the device 102, the protocol conversion apparatus 100 next transfers the request CI 2 to the device 102.

The protocol conversion apparatus 100 receives a request directly from the PLC 101 when waiting for a response to the request CI2 received from the device.
In this case, the protocol conversion apparatus 100 converts the direct request so as to conform to the network B 104, and then transfers the direct request to the device 102 before the request CI3. Then, the protocol conversion apparatus 100 converts the response of the direct request received from the device so as to conform to the network A103, and then transfers the request CI3 that has been converted so as to conform to the network B104 to the device B102. Forward to.

When the request CI 3 received from the device is received, the protocol conversion apparatus 100 converts all the responses of the requests CI 1 to 3 received from the device so as to conform to the network A 103, stores them in one frame, and transfers them to the PLC 101.

Therefore, the protocol conversion apparatus 100 includes the first network A103 that supports both a protocol that alternately performs a request and a response to the request, and a protocol that transmits a plurality of requests as one frame without waiting for the request and the response to the request. A first interface 1 that transmits and receives a frame, and a second interface 2 that transmits and receives a frame, and is connected to a second network B 104 that supports only a protocol that alternately performs a request and a response to the request. One frame corresponding to one request conforming to the second network B104 for the frame including the direct request that is the request to be preferentially processed received by the first interface A103 and the frame in which a plurality of requests are bundled As well as directly received by the second interface. A response to the request is converted into a frame suitable for the first network A103, and a single response frame corresponding to one request is converted into a single frame in which a plurality of responses suitable for the first network A103 are bundled. The protocol conversion unit 3 and the frame converted so as to be compatible with the second network B104 are subjected to the first response according to whether a response is received from the second network B104 and whether there is a direct request from the first network A103. 2 to select the frame to be output to the interface 2 of the second network, and to the first interface 1 according to the presence / absence of a direct response from the second network B104 to the frame converted to be compatible with the first network A103. Since the output control unit 4 that selects the frame to be output is provided, Even in the case of relaying a network with that protocol, the priority data to be synchronized of the request can be processed preferentially.

Embodiment 3 FIG.
In the third embodiment, a case will be described in which all the configurations of the second embodiment are provided and there is priority processing in the response to a plurality of requests bundled in one frame in the network A103.

FIG. 9 is a diagram illustrating an example of a sequence performed by the protocol conversion apparatus 100 when a plurality of commands are collected into one frame from the network A 103 according to the third embodiment. *

In FIG. 9, the connection (CONNECTION) establishment and connection termination steps shown in the first embodiment are the same as those in the first embodiment, and are therefore omitted.
After the connection between the PLC 101 and the device 102 is established, the PLC 101 aggregates the requests CI1 to CI3 (CI is an abbreviation for a control instruction, and a number is a control instruction number) into one frame as shown in the lower part of FIG. It transmits to the device 102 in the state. Thereafter, it is assumed that the PLC 101 immediately transmits a direct request to the device 102 that needs priority control.
In the second embodiment, the responses of all the requests CI1 to CI3 are bundled into one frame, but in this embodiment, the request CI1 is defined as a priority request, and all the requests CI1 to CI3 Even so, a case will be described in which the response of the request CI1 has priority and needs to be responded immediately in another frame.

The protocol conversion apparatus 100 extracts the received requests CI1 to CI3 one by one from the frame and converts them so as to conform to the network B104, and then transfers the request C1 defined as a priority request to the device 102.
Upon receiving the request CI1 response from the device 102, the protocol conversion apparatus 100 converts the request CI1 so as to be compatible with the network A103, and then transfers it to the PLC 101 and transfers the request CI2 to the device 102.

When the request CI 3 received from the device is received, the protocol conversion apparatus 100 converts the responses of the requests CI 2 to 3 received from the device so as to conform to the network A 103, stores them in one frame, and transfers them to the PLC 101.

Next, the configuration and operation will be described. Although the configuration itself of the protocol conversion apparatus 100 in the third embodiment is not changed from that in FIG. 6 of the first embodiment, the processing contents in the protocol conversion unit 3 and the output processing unit 4 are particularly different as in the second embodiment. .
The operation of the protocol conversion apparatus 100 will be described.
FIG. 10 is a flowchart of the operation of the protocol conversion apparatus 100 that operates in the sequence of FIG.

The numbers in the flowchart in FIG. 9 are the same as those in FIG. Of the step numbers in FIG. 9, the details of the parts changed from FIG. 5 are based on the second embodiment. With respect to FIG. 10, a portion having a change compared to FIG.
In step S901, there are three types of responses to requests: responses to direct requests, requests for priority processing requests, and responses to normal requests. Either of them needs to be converted into a protocol compatible with the network A103. The protocol conversion unit 3 of the protocol conversion apparatus 100 in FIG. 6 stores the response to the direct request and the priority processing request individually in a frame and outputs the response to the output control unit 4. In response to a response to an ordinary request, a plurality of responses are stored in one frame and then output to the output control unit 4.

If there is no direct request response in step S510 of FIG. 10, it is checked in step S902 whether there is a response to the priority processing request. If there is a response, the priority request response is sent via the network A103 to the PLC 101 in step S903. If not, in step S904, a response to a plurality of requests in one frame is transferred to the PLC 101 via the network A103. The output control unit 4 processes steps S510, S511, and S902 to 904.

In the present embodiment, since the request for preferential processing is stored in the first CI 1 among the frames CI 1 to 3 in which a plurality of requests are bundled, the protocol conversion apparatus 100 transfers the request. In this case, there is no difference from the second embodiment. However, when the request for preferential processing is stored in CI2 or 3 among the frames CI1 to CI3 in which a plurality of requests are bundled, steps S902 to S904 in FIG. CI2 or CI3 can be preferentially transferred to the device 102 side by incorporating the same processing on the NO side of step S505 in FIG.

Therefore, the protocol conversion apparatus 100 is
It is connected to the first network A 103 corresponding to both a protocol that alternately performs a request and a response to the request and a protocol that sends a plurality of requests as one frame without waiting for a request and a response to the request, and transmits and receives frames. The first interface 1 is connected to the second network B 104 that supports only the protocol that alternately performs the request and the response to the request, and is received by the second interface 2 that transmits and receives frames and the first interface A 103. One corresponding to the second network B 104 for a frame including a direct request which is a request to be preferentially processed and a frame including a plurality of requests including a priority request to be preferentially processed. Direct request received on the second interface or One frame in which a response to the priority request is converted into a frame suitable for each first network A103 and a plurality of responses suitable for the first network A103 are bundled with respect to one response frame corresponding to one request. Depending on whether or not a response is received from the second network B 104 and whether or not there is a direct request from the first network A 103 with respect to the protocol conversion unit 3 that converts to the second network B 104 The second interface 2 selects a frame to be output to the second interface 2 and determines whether or not there is a direct request response and a priority request response to the frame converted to be compatible with the first network A103. In response, select a frame to be output to the first interface 1 Since an output control unit 4, even in the case of relaying a network with different protocol, the priority data to be synchronized of the request can be processed preferentially.

The output control unit 4 also outputs a frame to be output to the second interface 2 according to whether a response is received from the second network B 104, whether there is a direct request from the first network A 103, and whether there is a priority request. By selecting, it is possible to preferentially process priority data that requires more synchronization even when relaying networks having different protocols.

DESCRIPTION OF SYMBOLS 1 1st interface 2 2nd interface 3 Protocol conversion part 4 Output control part 100 Protocol conversion apparatus 101 PLC
102 device 103 network A
104 Network B

Claims

Connected to a first network corresponding to both a first protocol that alternately performs a request and a response to the request and a second protocol that sends a plurality of requests without waiting for a response to the request, A first interface for transmitting and receiving;
A second interface connected to a second network supporting only the first protocol and transmitting and receiving a frame;
A frame including a request received at the first interface or a direct request that is a request to be preferentially processed is converted into a frame suitable for the second network, and the request received at the second interface or A protocol converter for converting the frame of the response of the direct request into a frame suitable for the first network;
A frame to be output to the second interface is selected according to whether or not a response from the second network is received and whether or not the direct request is received from the first network. An output control unit that selects a frame to be output to the first interface according to the presence or absence of a response to the request;
A protocol conversion apparatus comprising:
The first interface transmits and receives in one frame to the plurality of requests and responses to the plurality of requests in the first network,
The protocol conversion unit converts a plurality of requests included in the one frame into one frame corresponding to one request adapted to the second network, and for a response to the plurality of requests, 2. The protocol conversion apparatus according to claim 1, wherein the protocol conversion apparatus converts the frame into one frame corresponding to the plurality of requests adapted to the first network.
The first interface receives, in one frame, the plurality of requests including the priority request to be preferentially processed in the first network, and one response to the priority request to be preferentially processed. Transmit in a frame, and transmit in a single frame for a plurality of responses other than the priority request,
The protocol conversion unit converts a response to the priority request into a single frame corresponding to the request for the priority request adapted to the first network, and a response to the plurality of requests other than the priority request. 3. The protocol conversion device according to claim 2, wherein the protocol conversion device converts the frame into one frame corresponding to the plurality of requests adapted to the first network.
The output control unit outputs a frame to be output to the second interface 2 according to whether a response is received from the second network, whether there is the direct request from the first network, and whether there is a priority request. The protocol conversion device according to claim 3, wherein the protocol conversion device is selected.
5. The gateway device according to claim 1, a PLC that is connected to the first network, transmits the request and receives a response to the request, is connected to the second network, and An industrial network system comprising: a device that receives the request adapted to two networks and transmits a response to the request.