JPH04172502A - Internetwork communication method in programmable controller - Google Patents

Abstract

PURPOSE:To make it possible to quickly deal with a relay error when it occurs by returning an address indicating a place where the relay error occurs, a cause of the relay error, and a flag representing the relay error to a sender's node. CONSTITUTION:When a CPU 22a of communication unit 22 receives a command, in order to specify a sender's node the CPU 22a retrieves a routine table stored in work RAM 22e. Further, when a relay destination is already set, data is sent to the set relay destination, and if there is a transmission error, the relay destination sends back an error response. That is, CPU 22a of this relay PC (programmable controller) that is the relay error generating node sets the network address of a network to which the communication unit 22 is connected, the node address of the unit 22, a relay error flag indicating that this flag is the relay error, and a terminating code in which a code number of the cause of relay error is written, and sends a constituted frame back to the sender's node.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inter-network communication system in a programmable controller (hereinafter referred to as a PC) that relays data communication between networks to which a plurality of nodes are connected.

(Prior art) Conventionally, P
There is a method in which the CPU of the main body of C or a node (communication unit) searches for a routing chip stored in an internal memory and performs communication based on the routing chip.

In this network communication system, when a relay error occurs in a PC node (communication unit) that relays between networks, the frame (data) being transferred is discarded at the node where the relay error occurs.

Note that a routing table is an address that indicates the communication route from the node of your own PC to the final target PC node of another network, such as the address of the network that passes in between (hereinafter referred to as network address), The address of a PC node (hereinafter referred to as a node address) that relays between PCs is set.

(Problem to be Solved by the Present Invention) However, in the conventional inter-network communication system as described above, when a relay error occurs, the frame being transferred at the node where the relay error occurred is discarded. There is a problem in that the source node cannot immediately detect the location where the relay error has occurred and the cause of the relay error, and cannot promptly respond to the occurrence of the relay error.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a PC network communication method that can quickly detect the location of a relay error and the cause of the relay error when a relay error occurs. purpose.

(Means for Solving the Problems) In order to solve the problems described above, the present invention provides an inter-network communication system in a programmable controller that relays data communication between networks to which a plurality of nodes are connected, in which relay errors occur. In some cases, the present invention is characterized in that an error response replying means is provided for returning an address indicating the location where the relay error has occurred, the cause of the relay error occurrence, and a flag indicating the relay error as a response to the transmission source node.

In the above configuration, when a relay error occurs, the error response reply means returns an address indicating the location where the relay error has occurred, the cause of the relay error occurrence, and a flag indicating the relay error to the source node as a response.

Therefore, the source node can immediately detect the location where a relay error occurs and the cause of the error.

(Embodiment) Hereinafter, an embodiment of the inter-network communication method in a PC according to the present invention will be described based on the drawings.

FIG. 1 is a block diagram illustrating an inter-network communication method in a PC that relays between networks (hereinafter referred to as a relay PC). Network X is connected to communication units 22 and 23, respectively.

Y is connected and relays between networks. The relay PC 2 can increase or decrease the number of networks to be relayed by increasing or decreasing the number of communication units, but in this embodiment, it is assumed that the relay PC 2 relays between two networks.

In addition, in the same figure, PCI and 3 are also respectively PC main body 11
．． A communication unit 12.32 is connected to the communication unit 1.2.31. 32 is network X, Y
is connected to.

The PC main body 21 and the communication unit of each PCI, 2.3, are configured and connected as shown in FIG. do.

First, the PC body 21 includes a CPU 21a and a system ROM.
21b, a work memory 21c, a user program memory 21d, an attendance memory (I10 memory) 21e, a clock generation circuit 21f, and an interface (1/F) 21g connected to the communication unit 22.

The system ROM 21b includes the CPU 21a.
However, the routine table set in advance by the user using a block programming tool or the like is first stored in the ROM area of the work memory 21c for backup, and then the routine routine table written in -1- is read out and written to the RAM area. The system program programmed into the system is stored.

The communication unit 22 also has a CP that controls the inside of the unit.
U22a, system ROM22b, buffer memory 22c, communication controller 22d, work RAM2
2e, a driver/receiver 22f that is connected to the network X to transmit and receive data, and an interface (1/F) 22g that is connected to the PC main body 21.

In this embodiment, the CPU 22a of the communication unit 22 reads out the routing cheese from the work memory 21C of the PC body 21 and stores the work RA in the own communication unit 22 in the system ROM 22b of the communication unit 22.
Write (storage) routine code to M22e
It has a built-in system program that is block-coded like this.

The system ROM 22b also contains the communication unit 2.
2's CPU 22a uses the work RAM during data communication relay.
22e and determines whether or not there is a routing chip, as will be described later.
Multi-step judgment is performed such as determining the destination of the network address, node address, and machine number (machine number), and when the destination node can be identified, data is sent to that destination node. A system program is also stored that is programmed to send an error response, that is, a frame to be described later, as an error response to the source node when it is determined that the error is a pull error.

However, in this embodiment, the system program is programmed so that the above-mentioned error response occurs only when a command response is requested, and in the case of no response/response, the node is discarded even if there is a relay error.

In addition, the frame that is multiplied by one move when responding to the error mentioned above is the third frame.
It is configured as shown in the figure, and this frame is used for relay errors (
A flag indicating that the error is due to a routine error (routine error flag), an exit code indicating the cause of the error, the network address of the node where the relay error occurred, and the node address are set. There are codes that indicate the cause of the error, such as not being able to send, a problem with the PC itself, or a routine failure (remember that the number of relays is too many).

In this embodiment, the routing team consists of a local network table and a relay table.

As shown in Fig. 5, the own network table contains the number of configured networks, the number of times the communication unit has passed through the gateway, the own network address of the network connected to the communication unit, and the address space that is the connection position of the communication unit within the PC. 01 number (machine number) is set for each communication unit. However, units that can transmit and receive via communication units installed in the same Pct- without being directly connected to a communication line have a network address, a node address, only a machine number (machine number), and are connected to their own network. Not set in the table.

In addition, the relay table is a table for determining the transmission route of the communication unit of the own PC, and is used to find the relay node address within the own network, and is set when the final network to be the destination is other than the own network.
As shown in the figure, the number n of set networks, the final network address, the network address of the relay network, and the node address of the relay network are set for each set network.

Next, the operation of the inter-network communication method in the PC of this embodiment configured as described above will be explained based on the flowchart of the routing multiple determination process shown in FIG.

First, connect the network I/W as shown in Figure 1.
, Y, in order to send a command to the communication unit 12 of PCI of network X or the communication unit 32 of PC3 of Neno I/Work Y, the command is sent to the communication unit 22 of middle mPC2.

When the CPU 22a of the communication unit 22 receives the command, it searches the routine code stored in the work RAM 22e of its own communication unit 22 in order to specify the destination node (destination node), and executes a routine as shown in FIG. Start the process of determining the group.

That is, first, the CPU 22a of the communication unit 22 determines the presence or absence of a routing chip (ST100).

Next, the CPU 22a performs a routing check (S
T100 "Yes"), it is determined whether the network address is addressed to the own network address (ST200).

If it is addressed to the own network address, then it is determined whether the node address is addressed to the own node or not (5T3).
00), if it is addressed to the own node (ST300 “Yes”),
Furthermore, it is necessary to determine whether or not the machine number is the own machine light.
T400), if the own machine lights up (ST400 'Ye
s”), processed within its own node (ST500),
Let it end.

By the way, when determining whether or not the destination is addressed to the own network address (ST200), if it is not addressed to the own network address (ST200 "NO"), next check whether or not the corresponding relay destination is set in the routing number, that is, the network Determine whether the address and node address are set (5T210), and if the corresponding relay destination is set (ST210 "Yes"), send to that relay destination (5T220), and the transmission ends normally. It is determined whether or not (ST230), and if the transmission is normal (ST2
30 “Yes”), but if there is no corresponding relay destination (ST210 “NO”) or if the transmission is abnormal (ST210 “NO”)
T230 "No"), an error response is made due to an error in the middle 9p (ST600).

In other words, the CPU 22a in the communication unit 22 of this relay PC 2, which is the node where the relay error occurred, inputs the network address of the network to which the own communication unit 22 is connected, the node address of the own communication unit 22, and the relay error occurred in this frame. A relay error flag (routine error flag) indicating that there is a relay error flag and an end code containing the code number of the cause of the error are set, and a frame configured as shown in Figure 3 is sent to the source node as an error response. Reply.

Also, in the destination determination of the above node address (ST
300) If it is not addressed to the own node, that is, if it is addressed to another node (ST300 "NO"), an error response is sent as described above (ST600).

Also, at the time of determining the upper symbol machine number (ST400),
If it is not the own machine light, that is, it is addressed to another machine (ST40
0 “No”), please send it to the other device that is the relay destination 5
T220), and then the determination process of 5T220 or less is performed as shown in "-2".

Furthermore, in the determination of whether or not there is a routing number (ST100), if there is no routing number (ST100 "No"), it is determined whether the destination network address is 0 or not (5T110). If is 0 (STIIO “Yes”), then it is determined whether the node address is addressed to the own node or not. 5T3
00), and thereafter performs the determination process below 5T300 as described in -1-, while if the destination network address is not O (STIIO "No"), an error response is returned as described above (ST 600).

Therefore, in this embodiment, when a relay error occurs, the node where the relay error occurred sends a frame containing the network address and node address indicating the location where the relay error occurred, and an end code indicating the cause of the relay error as an error response. Since the reply is sent to the source node, the source node can recognize which network node the relay error occurred in, and can also refer to the termination code and a table that has been associated with that termination code in advance. This allows you to recognize the cause of the error.

Therefore, it is possible to obtain a network I-to-network communication system in a PC that can quickly deal with the occurrence of a relay error.

In this embodiment, if no relay error occurs and the transmission from the communication unit 22 to the communication unit 23 is completed normally, the communication unit 23 searches for the routing chip within its own communication unit 23. , the communication unit 22 performs the same determination process, and if there is no relay error here, the command can finally be sent to the communication unit 32 of the PCB which is the destination node (destination node). If this occurs, the communication unit 23
Similar to the communication unit 22, the communication unit 23 returns a frame set with the network address of its own communication unit 23, a node address, and an end code indicating the cause of the relay error to the communication unit 12, which is the source node, as an error response.

In addition, the patterns in which a command relay error occurs in a communication unit (node) are when receiving a command from a node of another PC as shown in Figure 7 (a), and when receiving a command from a node of another PC as shown in Figure 8 (a). There are three patterns when the own PC receives commands from other nodes, and when the own node sends commands to other nodes of the own PC or to nodes of other PCs as shown in FIG. 9(a). I can think of it.

In such cases, Fig. 7 (b) and Fig. 8 (
b), the determination is made as shown in FIG. 9(b), and the final processing is performed as shown in FIG. 10.

(Effects of the Invention) As explained above, in the present invention, when a relay error occurs,
The address indicating the location where the relay error occurred, the cause of the relay error occurrence, and a flag indicating the relay error are sent as a response to the source node, so the source node can immediately detect the location where the relay error occurred and the cause of the error. Therefore, it is possible to quickly deal with the occurrence of a relay error.

[Brief explanation of the drawing]

Fig. 1 is a block diagram illustrating the inter-network communication method in a PC that relays between networks, Fig. 2 is a block diagram showing the configuration and connection status of the PC main body and communication unit in the PC, and Fig. 3 4 is an explanatory diagram showing the frame structure of an error response, FIG. 4 is a flowchart showing the routine procedure for determining the number of routines in the communication system between real and work systems of this embodiment, and FIG. Table memory showing the structure of the table, Fig. 6 is inside! Table memory showing the structure of the table, Fig. 7 (
(a) is a block diagram showing a case where a notebook receives a command from a node of another PC; (b) is an explanatory diagram showing routine multiple determination processing in the case of (a);
FIG. 8(a) is a block diagram showing a case where a node receives a command from another node of its own PC, and FIG. 8(b) is an explanatory diagram showing the routing multiple determination process in the case of FIG. 8(a). , Figure 9(a) is a block diagram showing the case where a command is sent from the own node to the music node of the own PC or to a node of another PC, and Figure Cb) is a routine block diagram for the case of Figure 9(a). - An explanatory diagram showing pull determination processing,
Figure 10 is Figure 7(b), Figure 8(b), Figure 9(b)
FIG. 2 is an explanatory diagram showing the final processing in FIG. 1,, 2. 3... PC (programmable controller) 1.2.22, 23.32... communication unit
(Node) X, Y...Network patent applicant Omron Co., Ltd. Agent Patent attorney Kazu

Claims (1)

[Scope of Claims] 1. In an inter-network communication system in a programmable controller that relays data communication between networks to which a plurality of nodes are connected, when a relay error occurs, an address indicating the location where the relay error occurred and the occurrence of the relay error. An inter-network communication method in a programmable controller, characterized in that an error response return means is provided for returning a cause and a flag indicating a relay error to a source node as a response.