JPH03280641A - Transmission control method - Google Patents

Abstract

PURPOSE:To avoid deterioration in the transmission efficiency and response delay by registering a function code before relay and a function code after relay in pairs for function codes set to each repeater and setting a function code to be relayed to only a required repeater. CONSTITUTION:A function code representing a content of a message is added to each message, and a function code before relay and a function code after relay corresponding to the function code before relay are registered to each of repeaters 1020, 1330 and 2133. When a message is inputted from a loop transmission line 1 connecting to, e.g. the repeater 1020, a function code after relay corresponding to a function code before relay is added to the inputted message when a function code coincident with the function code of the inputted message in the function code before relay registered in the repeater 1020, the function code after relay corresponding to the code is added to the inputted message and the result is sent to other loop transmission line 2. Thus, the message is sent through only a loop requiring the message and the delay in response is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission control method for a transmission system comprising a plurality of loop transmission lines, and particularly to a transmission control method suitable for an autonomous decentralized transmission system.

[Conventional technology]

For multi-loop transmission systems in which multiple loop transmission paths (hereinafter simply referred to as loops) are interconnected, all transmission control devices on the loops have the same configuration, and each transmission control device has the same configuration and receiver address. A transmission control method in which messages are transferred between loops according to the contents of data without the user's knowledge is disclosed in Japanese Patent Laid-Open Publication No. 166756/1983. In this method, two memories are provided in a relay device that connects the loops, and a function code indicating the content of the message is attached to each transferred message.

The contents to be received within each loop are registered in advance in each of the memories using the codes described above. When data is sent on a certain loop and input to a relay device, the relay device registers the function code of the sent data in the memory corresponding to the loop on the opposite side from where the data was sent. The data is relayed to the opposite loop only when it is present. Furthermore, each transmission control device on the loop examines the code of the data sent on the loop, and examines only the data that is captured by its own device. According to this conventional example, information to be passed between loops can be easily selected and specified depending on the situation, and there is no need to create a transmission control device exclusively for relaying.

In addition, the method disclosed in JP-A No. 61-245651 uses the same configuration as above, adds the source address and serial number necessary for transmission to the data to be transported, and A relay device stores a fixed number of source addresses and serial numbers of the latest data relayed through the relay device. Then, when data with a function code that requires relaying is sent to the relay device, only the data that does not have the stored source address and serial number is relayed to another loop,
This prevents data from continuing to circulate between multiple loops.

[Problem to be solved by the invention]

In the prior art disclosed in Japanese Unexamined Patent Publication No. 57-166756 mentioned above, the function code indicating the content received by the transmission control device in each loop is set in all relay devices. For this reason, a message passing between loops is transmitted not only to the loop that requires the message, but to all loops that make up the multi-loop. Furthermore, this method has a problem in that when a plurality of loops constitute a closed loop, a message that has been generated once may continue to circulate in the closed loop. , this latter problem can be avoided by the technique shown in Japanese Patent Application Laid-Open No. 61-245651, but because of the former problem, in other words, messages that pass between loops are transmitted to all loops. However, there is a risk that the amount of transmission on the loop will increase unnecessarily, exceeding the maximum amount of transmission on the loop, or that there will be a delay in responding to necessary messages. In addition, the function code in one message remains the same no matter which loop it is sent to, so when multiple existing loops are connected using this method, each loop has the same function code before connection. may be used, in which case the same function code would represent different contents, and they would exist on the same loop. This poses a problem in that the duplicate code cannot be used as a code representing the content of the data.

An object of the present invention is to have all transmission control devices on a loop have the same configuration, so that each transmission control device can transfer messages without knowing the multi-loop system structure or the address of the receiving side, and can transfer messages between loops. The object of the present invention is to provide a transmission control method that transmits the message only to the loop that requires it, and also allows the function code in the message transmitted within the loop to be transmitted without changing the existing loop system to which it is connected. An object of the present invention is to provide a transmission control method that prevents duplication even when the data is transferred.

[Means to solve the problem]

In order to achieve the above object, in the present invention, logical relay device numbers are registered in advance in relay devices between loops,
When registering a function code for the content of a message to be relayed, set the function code using the above relay device number only to the relay device that needs to relay the message with that function code, and also set the function code to each relay device. The code registers a pair of pre-relay function code when it enters the relay device and relay removal function code that is added to the relayed message, and when the relay device receives a message from one loop, the same code is registered. If there is a pre-relay function code in the loop registration area that is the same as the function code in the message, it is converted into a corresponding function code and the message is transmitted to the other loop.

[For production]

By identifying relay devices by their numbers, the function code to be relayed is set only to the necessary relay devices, which prevents messages from flowing between loops unnecessarily.
There is no reduction in transmission efficiency or response delay. Furthermore, since function codes can be converted for each relay, duplication of function codes can be avoided in any loop, and existing loops can be connected flexibly.

〔Example〕

An embodiment of the present invention will be described below. FIG. 2 shows an example of the overall configuration of a system implementing the present invention, in which three loops 1, 2.3 are connected to a transmission control device (netgork
communication processor;
(hereinafter referred to as NCP) via a processing device.

Specifically, loops 1 and 2 connect to the NCPs 21 and 33 and the processing device 21 via the NCP Io, 20 and the processing device 1020.
Loops 2 and 3 are connected through 33, and loops 1 and 3 are connected through NCPs 13 and 30 and a processing device 1330.

On each loop, NCPIO~13.20~23.30
.about.33 are connected to each other. NCPII~12.
22-23, 31-32, processing devices 1100-12
00.2200-2300 and 3100-3200 are connected, respectively. NCPIO and 20.21 and 33.
13 and 30 have a common processing unit 1020, 2] 33.1
330 are connected to each other (hereinafter these will be referred to as relay processing devices). NCP], O~13°20~23.3
0 to 33 all have the same configuration, and the structure does not differ depending on whether or not they are connected to a relay processing device. Each NCP is
It captures only the necessary messages from the messages flowing on the loop and sends them to the corresponding processing device. Also, messages sent from the processing device are sent onto the loop. Here, each NCP does not set a receiving address in the message so that it can receive the message without knowing the system configuration, which loop the receiving NCP belongs to, or what the address is.

FIG. 3 shows the format of messages transmitted by this system. (a) is a normal message format, and (b) is a message for function code registration. Among the fields in FIG. 3(a), FC is a function code, which corresponds to the content of the data. S
A is the address of the NCP that created and sent the message (source address), CC is the serial number necessary for transmission, and Dat
a is the information to be processed. Further, FC3 is error detection data, and F is a flag indicating the beginning and end of the message. Each NCP performs transmission control using fields F, FC, SΔ, and FC8, and is not concerned with Data. Each NC
By comparing the function code registered from the processing device connected to itself with the FC field of the message on the loop, P determines whether the processing device needs the message and makes it necessary. Retrieve messages only if When data is generated, each processing device sets the data content and function code in the Data field and FC field and sends it to the self-connected NCP. Each NC
P receives the message from the self-connected processing device as shown in Figure 3 (
It formats itself into the format shown in a) and sends it to the loop as the source. Furthermore, each NCP takes in the message that it sent as the sender and returns after going around the loop, and deletes it from the loop. If the message does not return within a certain period of time, this message will be retransmitted a certain number of times until it returns. Such NCP transmission control processing is completely the same for all NCPs.

On the other hand, among the fields in FIG. 3(b), FCr is
This is a registration function code for registering a pre-relay function code and a post-relay function code of a message to be relayed to a relay processing device. Further, LN in the Data field is the logical repeater number of the relay processing device to which the pre-relay message is to be relayed, PCI is the function code of the pre-relay message, and Fe2 is the function code of the post-relay message. Each NCP processes this function code registration message in the same way as a normal message.

Next, each relay processing device 1020.2133.1330.
and processing device 1100.1200.2200.2300
．． Transmission control processing in 3100 and 3200 will be explained. The configurations and processing flowcharts of all relay processing devices and processing devices are the same, and FIG. 4 is a block diagram showing the configurations of these processing devices. This is the relay processing device 102
0 is shown as an example, and is connected to NCPIo and 20, which are connected to loops 1 and 2, respectively, and performs transmission with each loop via interfaces 311 and 321.

Further, the processing arithmetic unit 310 performs transmission control processing, and controls the first reception buffer 313 and the second reception buffer 3.
23 is a buffer for storing received data corresponding to each loop, and the first FC registration area 314 and the second FC registration area 324 register the pre-relay function code and post-relay function code of the message that crosses the loop. The first transmission buffer 315 and second transmission buffer 325 are buffers for storing data to be sent to each loop, and the first reception data area 316 and second reception data area 326 are This is an area for storing data to be used by a relay processing device or a processing device. Further, the relay device number area 320 is an area in which the logical relay device number of the relay processing device is registered when the processing device is connected to two loops and is treated as a relay processing device that needs to relay messages. .

Therefore, in the relay processing device, a logical repeater number of zero or more is registered in the repeater number area 320, and in other processing devices, a value of zero is registered in the repeater number area 320.

FIG. 5 shows the contents of the first FC registration area 314, which is composed of a pre-relay function code registration area 3141 and a post-relay function code registration area 3142, and the pre-relay function code FC1i and the post-relay function code FC2i are on a one-to-one basis. Compatible.

FIG. 1 is a flowchart showing an embodiment of processing, which is a feature of the present invention, in a relay processing device and a processing device.
When a message is received from the NCP of one loop, the contents are first transferred to the corresponding reception buffer 313 or 323.
(step 351).

Next, the function code in the message is identified and it is determined whether it is a registration message or a normal message (step 352). If the message is for function code registration, the logical repeater number LN in the message is compared with the repeater number in the repeater number registration area 320, and if they are the same, the own processing device registers the message as a function code for relaying. If it is determined that it is necessary, the next process is performed, but if it is different, the process is ended without doing anything (step 359). Note that if it is not a relay processing device, the relay device number in the relay device number area 320 will not be registered and the value will be zero, so the determination here will always be different and nothing will be done. The function code is registered in the FC registration area 314 opposite to the received loop.
Store the pre-relay function code PCI and post-relay function code FC2 in the message (Step 360), register the post-relay function code FC2 in the NCP of the received loop (Step 361), and register the post-relay function code FC2 in the NCP of the received loop. NCP
(Step 362)
,finish. Furthermore, in the case of a normal message, the contents of the reception buffer are stored in the reception data area corresponding to the received loop as data for use in the own processing device (step 353). Furthermore, check whether the repeater number is registered in the repeater number registration area 3320 (
Step 354), if there is registration, check whether there is the same function code in the function code in the received message and the pre-relay function code area of the FC registration area 314 or 324 corresponding to the received loop (step 355), If there is a function code, it is determined that the message needs to be relayed and is treated as a message that crosses between loops. Step 3
If no repeater number is registered in step 54, or if no identical function code is found in step 355, it is determined that the relay processing device is not a relay processing device, or that the message does not need to be relayed, and nothing is done. If there are identical function codes in step 355, the function code PCI in the received message is converted to the post-relay function code FC2 corresponding to the pre-relay function code in the FC registration area (step 356), and the message is received. The message is stored in the sending buffer 315 or 352 opposite to the loop (step 357), and the message is sent to the NCP in the opposite loop to the receiving loop (step 358), and the process ends.

The NCP that receives this message becomes the sender, formats it in the format shown in FIG. 3(a), and sends it out on the loop.

Through the processing of the above relay processing device and processing device.

If a message received from an NCP is for function code registration, it will be registered only in the relay processing device connected to the loop through which the requested message flows, and if it is a normal message, there is no need to cross between loops. A message is passed through a relay processing device only to loops that require it, without changing the data in the message.
Only the function code is converted and relayed. This allows each message to be transmitted only in the loops that require it, and to avoid duplication of function codes in one loop.

Next, the flow of data within the transmission system in this embodiment will be explained using FIG. FIG. 6(a) shows the data flow of the function code registration message. First, the processing device 11200 generates data with the function code FCa, and the processing device 1100 receives and uses this data. shall be. In this case, data with function code FCa is being transmitted along path 411 within loop 1. next,
In order for the processing device 2200 to receive and use the data with the above function code FCa as data with FCb in loop 2, the processing device 2200 has the function code FCr as a message for function code registration. The data includes the logical repeater number LN of the relay processing device 1020, the pre-relay function code FCa, and the post-relay function code FCb, and is sent to the NCP 22. N CP 22 sends out the data, and as it travels along path 420 it is captured and erased. On the other hand, since FCr is registered in advance, CP2O takes in this message and relays it to relay processing device 1.
Send to 020. In the relay processing device 1o20, since the logical repeater number LN in the message is the number of the own device, the pre-relay function code FCa and the post-relay function code Feb in the message are registered in the own device, and the pre-relay function is sent to NCPIO. Register code FCa and register post-relay function code Feb in NCP2O. Also, since the FCr is registered in advance, the NCP 21 also captures this message and sends it to the relay processing device 2130, but the relay processing device ff 213
If it is 0, the number LN in the message is different from that of the own device, so nothing is done. As a result, the relay message FC
As a registration process, FCa is sent to the relay processing device 1020.

FCb is registered as a function code, FCa is registered in NCPIO, and FCb is registered in NCP 20 as a function code, and is not registered in the path to loop 3. In addition, NCPll and 12
FCa has already been registered in the , and FCb has already been registered in the NCP 22 from the processing device 2200 .

Next, the flow of the message having the function code FCa in loop 1 passing through the loop will be explained using FIG. 6(b). When the processing device 1200 generates a message with FCa, the NCP 12 receives this message, sends it to loop 1, and takes in and deletes the message that has gone around like path 411.

On the other hand, since the function code FCa is registered in its own device, NCPIO takes in this message and sends it to relay processing device 1020. Relay processing device 1020 stores the Data field in the message in the reception data area within itself, and also stores the function code F in the message.
Convert to Ca11F Cb and send to NCP2O. The NCP 2O sends this message onto the loop 2, and takes in and deletes the message that has made a loop like the path 421. Also, since the function code Feb is registered in its own device, the NCP 22 captures this message and sends it to the processing device 2200. Processing device 220
0, the data field in the message is stored in the local area and the processing is executed.

As described above, according to this embodiment, in a transmission system composed of a plurality of loops, all NCPs can be used without using a special NCP or a special relay processing device. It is possible to transmit necessary messages only to necessary loops without knowing which loop the receiving NCP is connected to, and to transmit between loops without duplicating function codes in each loop. becomes. Note that even if multiple loops are further connected to each loop in this embodiment, two
This method is effective even when it consists of only one loop.

FIG. 7 shows an example of the configuration of the processing device or relay processing device shown in FIG. The data is transferred to a storage medium 701, such as a floppy disk, provided externally. In this way, by storing the repeater number and function code conversion data in a storage medium separate from the processing device, normal message relay processing can be performed, and this data can only be sent to the processing device that performs the relay. Just set it.

Note that in the embodiment described above, one registration message sets one set of pre-relay and post-relay function codes in one relay processing device, but this is set in multiple relay processing devices. It is also possible to set a set of function codes. For example, three loops A, B, and C are connected serially, and a relay processing device TAB connects loops A and B, a relay processing device TBC connects loops B and C, and one Consider a case in which one processing device SC receives messages flowing through loop A. In this case, in order for the processing device SC to receive a message with function code FCA on loop A as a message with function code PCB on loop B and further as a message with function code FCC on loop C, It is necessary to set the pre-relay function code FCA and the post-relay function code PCB in the relay processing device TAB, and the pre-relay function code PCB and the post-relay function code FCC in the relay processing device TBC, and in the above embodiment, registration is required twice. It is necessary to issue a message for This is issued in one registration message with the numbers of the two relay processing devices 0TAB and TBC and the corresponding two sets of function codes as data to set the function codes to the two relay processing devices at once. By doing this, you can efficiently set the function code.

〔Effect of the invention〕

According to the present invention, in a transmission system composed of a plurality of loops, a message is transmitted only in the loops that require it and not in unnecessary loops, so that the transmission load within the loops is not increased unnecessarily. This also eliminates response delays.

In addition, each loop allows you to easily change the function code that represents the message content, so even if you connect existing loops together, the function code will not overlap in one loop. This has the advantage that a multi-loop system can be configured without any changes.

[Brief explanation of drawings]

Fig. 1 is a flowchart of the processing characteristic of the present invention, Fig. 2 is a diagram showing an example of a multi-loop system, Fig. 3 is an explanatory diagram of the format of a message to be transmitted, and Fig. 4 is an example of the configuration of a processing device. 5 is an explanatory diagram of the function code registration area, FIG. 6 is a diagram illustrating the flow of messages transmitted in the system, and FIG. 7 is a diagram illustrating another example of the configuration of the processing device. 1.2.3...Loop transmission line, 10-13.20-2
3゜30~33...Transmission control device (NCP), 110
0.1200°2200, 2300.3100.320
0... Processing device, 1020.2133°1330...
- Relay processing device, 314.324...FC registration area, 320...Relay machine number registration area, 701...Storage medium.

Claims (1)

[Claims] 1. A message transmission control method in a multi-loop system in which each of at least two or more loop transmission paths is connected by a relay device, wherein each message is provided with a function code indicating its content. and register the pre-relay function code and the corresponding post-relay function code for each code in each relay device, and when a message is input from one loop transmission path connected to the relay device. Then, if there is a function code that matches the function code of the input message among the pre-relay function codes registered in the relay device, the relay corresponding to the code replaces the matching relay function code. A transmission control method characterized by adding a post-function code to the input message and transmitting it to a loop transmission line connected to the other side of the relay device. 2. A registration message indicating that the function code is registration data and having the pre-relay and post-relay function codes as the data is provided, and the relay device to which the message is input from one loop transmission path , the transmission control according to claim 1, wherein the pre-relay and post-relay function codes in the message are registered in the own device, and the input registration message is sent to the other loop transmission path. Method. 3. Register a relay device number unique to each relay device, and include the registered relay device number in the data of the registration message, and each relay device registers the above-mentioned relay device number that matches the relay device number of its own device. 3. The transmission control method according to claim 2, wherein the pre-relay and post-relay function codes in the message are registered in the own device only when a registration message having a registered relay device number is input. 4. The registration message has a plurality of data pairs consisting of a pre-relay function code, a post-relay function code, and a registered relay device number, and the relay device to which the registration message is input from one loop transmission path is Only when the first data pair includes the relay device number of the own device, register the pre-relay and post-relay function codes of the first data pair in the own device, and send a registration message that erases the data pair. 4. The transmission control method according to claim 3, wherein the transmission is transmitted to the other loop transmission path. 5. The pre-relay and post-relay function codes and the relay device number are set in a storage device external to the relay device that can be read from the relay device and is detachable. Transmission control method.