JPH022259A - Local area network - Google Patents

Abstract

PURPOSE:To conduct the test of each data transmitter connecting to each processor quickly by returning a special test use loopback request frame from a processor of a sender and allowing a processor to conduct a reception reject reply test by intention continuously and automatically with respect to the loopback frame. CONSTITUTION:In the case of conducting a test of intentional 'reception rejection' by a processor 12 with respect to a loopback frame corresponding to a loopback request frame sent from the processor 12 between the processor 12 and a data transmitter 32, the loopback request frame is sent from the processor 12 and a loopback frame in response to the loopback request frame is subject to 'reception rejection' by the processor 12 and it is reported from the data transmitter 32 to the processor 12. The series of processing as above are implemented continuously and automatically. Thus, it is possible to control to execute the monitor processing after the test of 'reception rejection' is finished for the data transmitter 32, then the test of 'reception rejection' is conducted without the effect on the monitor processing of a maintenance monitor 50 to the data transmitter 32.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a data transmission system, and in particular, a plurality of data transmission devices disposed on a local area network transmission path, and a plurality of data transmission devices connected to each of the data transmission devices. The present invention relates to a local area network that is comprised of a processor and a maintenance/monitoring device installed for the purpose of monitoring and maintaining the local area network, and that transmits data in a frame-by-frame configuration.

[Prior Art] Conventionally, in this type of local area network,
Intentionally received by the processor in response to a special return frame for testing sent from the data transmission device connected to the processor to the processor, which is performed between a processor and a data transmission device connected to the processor. The rejection test is performed when the data transmission device connected to the processor receives a reception rejection response from the processor, and the reception rejection response is stored in the reception rejection response information storage area in the data transmission device. Since we are terminating the
Thereafter, the reception rejection response information area stored in the data transmission device was read out from the processor connected to the data transmission device to confirm the normality of the test. However, in the above-mentioned method, after the data transmission device stores the reception rejection response in the reception rejection response information storage area, the reception rejection response is maintained in the data transmission device by the processor connected to the data transmission device. If the maintenance monitoring device performs monitoring processing for the data transmission device before reading the response information area, the reception rejection response information stored in the data transmission device will be erased. The normality of the test cannot be confirmed. Therefore, before performing the above-mentioned test, in order to avoid the influence C caused by the monitoring process performed by the maintenance monitoring device on each data transmission device, the maintenance monitoring device must be manually operated by the operator to control the data transmission device to be tested. Measures were taken to ensure that the monitoring process for each data transmission device was not affected, and after the test was completed, the data transmission device under test was returned to its original state by manual operation.

[Problem to be Solved by the Invention] The conventional test method described above involves sending a special return frame for testing from the data transmission device to the processor between a processor and a data transmission device connected to the processor. In the case of transmission, when the processor intentionally makes a rejection response to the return frame, processing is performed at the time when the data transmission device stores the rejection response in a rejection response information storage area in the data transmission device. Therefore, if the maintenance monitoring device performs the monitoring process on the data transmission device before reading the rejection response information stored in the data transmission device from the processor, the rejection response information storage area This has the disadvantage that the information in the test is erased, making it impossible to confirm the normality of the test.Furthermore, manual operations by the operator are required before running the test to resolve the above-mentioned problems, making prompt maintenance difficult. There is a drawback that the operator cannot perform the work, and there is a possibility that malfunctions may occur due to incorrect operation by the operator.

[Means for Solving the Problems] In the local area network of the present invention, the processor sends back to the processor a return frame that uses the contents of the data portion of the frame transmitted from the processor as is as the data portion of the frame. a return request frame transmission mechanism that transmits a special return request frame for testing to a data transmission device connected to the processor, and a data transmission device connected to the processor,
Information indicating that when a return frame in which the destination address and source address of the return request frame received from the processor are exchanged is returned to the processor, the return frame is not normally received by the processor and a rejection response is received. and a reception rejection information frame receiving mechanism that receives a reception rejection ↑n report frame that reports a reception rejection information frame from a data transmission device connected to the processor to the processor, and the data transmission device receives a callback request frame that receives the callback request frame. When the return frame is received by a frame receiving mechanism, a return frame transmitting mechanism that transmits the return request frame, and a processor connected to the data transmission device, the return frame is connected to the data transmission device. a rejection response receiving mechanism that receives a rejection response when the processor does not normally receive the rejection response; and a reception rejection information frame transmitting mechanism that transmits the reception rejection information frame when the rejection response is received. 6 [Function 1] The present invention provides a method for controlling return frames transmitted from a data transmission device connected to the processor to the processor between a processor and a data transmission device connected to the processor. This allows the processor to automatically perform a test in which the processor intentionally responds with a reception refusal response. Each data transmission device connected to each processor can be quickly tested.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a local area network of the present invention, and FIG. 2 is a diagram showing a frame format used for data transmission in the local area network of FIG.

In this embodiment, a plurality of data transmission devices 31 to 3. ,
and a data transmission device 3. ~3n is the data transmission line 2. ~2
Processor II, 12.13, ~ connected via o
, and a maintenance monitoring device 50.

The processor 1□ sends a special return request frame for testing that instructs the processor 1□ to send back a return frame that uses the contents of the data portion of the frame transmitted from the processor 12 as is as the data portion of the frame. Data transmission device 3□ connected to the processor 12
The return request frame transmitter tA10 and the data transmission device 3□ connected to the processor 12 transmit the return request frame received from the processor 12, with the destination address and source address swapped, to the return request frame. reception rejection in which the data transmission device 3t connected to the processor 12 reports to the processor 12 information indicating that the return frame was not normally received by the processor 12 and a rejection response was received when the return frame was sent back to the processor 1□; It has a reception refusal information frame reception l11+m20 which receives an information frame. processor 1+,
13, . . . also have the same configuration as the processor 12.

The data transmission device 32 includes a return request frame receiver tAI00 that receives the return request frame, and a return frame transmitter 11 that transmits the return request frame.
0 and a processor 1 connected to the data transmission device 32
When the return frame is transmitted to □, if the return frame is not normally received by the processor 12 connected to the data transmission device 3□ and a rejection response is returned, the rejection response is received. and a reception rejection information frame transmitting mechanism 130 that transmits the reception rejection information frame when receiving the rejection response. Data transmission device 31.33 is also data transmission device 3□
It has the same configuration as .

In addition, a loop-shaped local area network transmission line 4
The information transmitted on the data transmission paths 21 to 2n is
It takes the frame format shown in the figure. The information to be transmitted is sandwiched between flags (hereinafter abbreviated as F) consisting of a specific bit pattern at the beginning and end of each frame to distinguish each frame. The information sandwiched between specific bit patterns F is the destination station address (hereinafter OA) that indicates the destination of the information to be transmitted first.
) is the source address (hereinafter referred to as SA) that indicates the source that will transmit the next information, and the control code (hereinafter referred to as CTL) that indicates the type of information that will be transmitted next is the information that will be transmitted next. (hereinafter abbreviated as DATA) is inserted at a certain length, and finally data (hereinafter abbreviated as FC3) that is the checksum of the entire transmission frame is added.

- As an example, the DAT of a frame transmitted from processor 1□ from processor 12 to data transmission device 3□
A special return request frame for testing is transmitted that instructs the processor 12 to return a return frame in which part A is used as the DATA part of the frame, and the data transmission device 3□ receives the return request frame and sends it to the processor 12. OA and SA of the return request frame received for
When the return frame with the replaced frame is returned, the processor 12 intentionally rejects the returned return frame, and the data transmission device 32 informs the processor 12 that the rejection response has been received. The operation of reporting using the reception refusal information frame held as information will be explained.

First, the processor 12 makes special settings in advance so that it always responds with a rejection response to the return frame transmitted from the data transmission device 32. Next, the second
A return request frame addressed to the data transmission device 3□ is created in the format shown in the figure. That is, the address of the data transmission device 32 is set in OA, the address of the processor 1□ in SA, a predetermined code indicating that it is a return request frame in CTL, and arbitrary data in DATA. The created return request frame is sent to the processor □
The return request frame is transmitted from the return request frame transmitting mechanism 10 of. The transmitted return request frame is transmitted to the data transmission device 3□ via the data transmission path 21. The return request frame transmitted to the data transmission device 3□ is received by the return request frame receiving mechanism 100 of the data transmission device 3□. The return request frame receiving mechanism 100 that has received the return request frame informs the return frame transmitting mechanism 11 that the return request frame has been received via the control mechanism 101.
Notify 0. Notified return frame transmitter +1
110 is the SA and DA of the received return request frame.
Replace. In other words, processor 2's a[
- Set the address of the data transmission device 32 in the response and SA. Furthermore, the return frame transmission mechanism +10 transmits a return frame with the addresses of SA and OA switched to the data transmission path 2□. The transmitted return frame is transmitted to the processor 2 via the data transmission line 22.

However, since the processor 2 is set in advance to reject the t heat 4 temple frame transmitted from the data transmission device 3□, the processor 2 does not normally receive the returned frame, and the data transmission device 3 returns a rejection response. This rejection response is received by the rejection response receiving mechanism +20 of the data transmission device 3□ via the data transmission path 22. Rejection response receiving mechanism 1 that received the rejection response frame
20 notifies the reception rejection information frame transmission mechanism 130 that a rejection response has been returned via the control mechanism +21.

The notified reception rejection information frame transmission mechanism +30 creates a reception rejection information frame indicating that the processor 12 has rejected the return frame corresponding to the return request frame transmitted from the processor 1□. . That is, in the format shown in FIG. 2, OA is the address of the processor 12, SA is the address of the data transmission device 3□, CTL is a predetermined code indicating that the frame is a reception rejection information frame, and DATA is an arbitrary rejection response. Set the data indicating each. The created reception refusal information frame is sent to the data transmission device 3□
The reception rejection information frame is transmitted from the WtA 130 to the data transmission path 22. The transmitted reception refusal information frame is received by the processor 1□ via the data transmission path 2□.

The processor 12 that has received the reception rejection information frame can recognize that the return frame corresponding to the return request frame transmitted from the processor 12 to the data transmission device 3□ has been successfully rejected by the processor 1□. At this point, the test for a rejection response to the return request frame ends.

From the above, between the processor 1□ and the data transmission device 3□, the processor 1□ intentionally sends a return frame corresponding to the return request frame sent from the processor 1□.
When performing a test that performs "Reception Rejection", after a return request frame is transmitted from Processor 1□, the return frame corresponding to the return request frame is "Receive Rejected"° and "Reception Rejected" by Processor 1□. The entire series of processing up to reporting from the data transmission device 3□ to the processor 12 can be performed continuously and automatically.

Therefore, it is assumed that the maintenance monitoring device 50 performs the monitoring process on the data transmission device 3□ while the above-mentioned “reception rejection” test is being performed between the processor 12 and the data transmission device 3□. Also, since the data transmission device 32 can be controlled to carry out the monitoring process after the above-mentioned “Reception Rejection” test is completed, the maintenance monitoring device 50 can monitor the data transmission device 3□. The above-mentioned "Reception Rejection" test can be performed without being affected by the processing.

In the above description, the processor 12 and the data transmission device 3□
Although we have described the case where the test is carried out between processors 1. and data transmission device 31, between processor 13 and data transmission device 3. It can also be implemented in the same way.

[Effects of the Invention 1] As explained above, the present invention provides a system between a processor and a data transmission device connected thereto, in which a special return request frame for testing is sent from the processor to the sender processor via the data transmission device. By continuously and automatically performing a test in which the processor intentionally sends a reception rejection response to the return frame, even during the test, the data transmission device to be tested from the maintenance monitoring device is This has the effect of being able to avoid interference caused by monitoring processing, and further has the effect of being able to perform maintenance work quickly, reducing man-hours and time, and preventing failures due to operator errors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the local area network of the present invention, and FIG. 2 is a diagram showing a frame format used for data transmission in the loop-shaped local area network of FIG. 11-13...Processor, 50...Maintenance monitoring device, 21-2o...Data transmission line, 3, -3o...Data transmission device, IO... ...Return request frame transmission mechanism, 2
0...Reception refusal information frame reception mechanism, 1
00...Return request frame receiver jR11
10...Return frame transmission mechanism, 120.
...Rejection response receiving mechanism, 130...
Reception refusal information frame transmission mechanism, 101, 121...
Control mechanism.

Claims (1)

[Claims] 1. A local area network installed for the purpose of monitoring and maintaining a plurality of data transmission devices disposed on a transmission path, a plurality of processors connected to each of the data transmission devices, and the local area network. In a local area network that includes a maintenance and monitoring device and transmits data in a frame-by-frame configuration, the processor transmits a return frame using the contents of the data portion of the frame transmitted from the processor as is as the data portion of the frame. a return request frame transmitting mechanism for transmitting a special return request frame for testing to the data transmission device connected to the processor; When a return frame in which the destination address and source address of the return request frame received from the processor are exchanged is sent back to the processor, information indicating that the return frame was not received normally by the processor and a rejection response was sent. a reception rejection information frame receiving mechanism that receives a reception rejection information frame to be reported to the processor from the data transmission device connected to the processor, the data transmission device receiving a callback request frame that receives the callback request frame. a receiving mechanism, a return frame transmitting mechanism that transmits the return request frame, and when the return frame is received by the processor connected to the data transmission device, the return frame is connected to the data transmission device. a rejection response receiving mechanism that receives a rejection response when the processor does not normally receive the rejection response; and a reception rejection information frame transmitting mechanism that transmits the reception rejection information frame when the rejection response is received. A local area network comprising: