JPS61244145A - Switching control system for serial data transmission line - Google Patents

Abstract

PURPOSE:To detect the states of two transmission lines of two systems at any times with a command of a message control word and to realize proper preventive maintenance by switching the transmission line within a specific limited time in test mode and removing the restriction the specific time later. CONSTITUTION:An input/output controller 100 receives and decide a message control word by a timer and switch circuit 111, a decision circuit 112, and a control word decoding means 113 to switch the transmission lines only within a specific time and removes the restriction the specific time later. Consequently, the states of the two transmission lines of two systems are tested by message transfer during maintenance and if a fault is found, it is repaired previously to perform preventive maintenance which is conventionally impossible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a serial data transmission path switching control method for controlling reception switching of two transmission paths in serial data transfer.

〔overview〕

The present invention provides a serial data transmission line switching control method that switches the transmission line only during a predetermined period of time during a test mode, and returns to the original state after the elapse of the predetermined time, so that the transmission line can be switched at any time by a command using a message control word. This system detects the state of the transmission line and allows appropriate preventive maintenance to be performed.

[Conventional technology]

Conventionally, this type of transmission line switching was performed only by a switching command within the input/output control device, and when the power was turned on, it was connected to any one of the two transmission lines, and the received data was being transferred. When an error occurs in the connected transmission line, the connection is automatically switched to another transmission line, data from the other system that is bumped by one word or more is adopted, and normal data transfer is continued. The switching operation was reported to the sender in the status word accompanying the message response.

[Problem that the invention seeks to solve]

In the above-mentioned conventional method, communication is possible if one of the two transmission paths is alive, and communication is not possible if both paths fail. However, switching is performed only after an error occurs, and it is only after switching that it is known whether the transmission line is normal or not, and it is not possible to predict if the other transmission line that is not currently connected is not working. Even when inspecting the yarn path during maintenance, it is only possible to determine whether the 1st path is OK or both 2nd paths are not working, and only the 1st path (because it is impossible to detect for emergency repairs if the other path is not working) The drawback was that it could not be maintained.

Accordingly, an object of the present invention is to provide a serial data transmission line switching control system that eliminates the above-mentioned drawbacks, thereby making it possible to detect the state of the transmission line at any time and to perform preventive maintenance.

[Means for solving problems]

The serial data transmission path switching control method of the present invention simultaneously transmits the same data to two serial data transmission paths, receives this data from only one of the transmission paths, and detects an error during data reception. In a serial data transmission line switching control method that automatically switches to the other transmission line when a transmission line occurs, the transmission line is switched only for a predetermined period of time in the test mode, and after the predetermined period of time has elapsed. It is characterized by controlling the switching back to its original state.

[For production]

In the present invention, in the test mode, the transmission line is switched only for a predetermined period of time, and is controlled to return to the original state after the elapse of the predetermined period. It is possible to detect whether the condition is good or bad by flowing it.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention, and FIG. 2 is a system diagram thereof.

This embodiment consists of two serial data transmission lines (1)l and (2)2, and an input/output control device 100 connected to them.

The input/output control device 100 includes an encoder 103, decoders 104 and 105, status response means 106,
Buffer circuit 107, 109, error detection selection circuit 10
8, a switch circuit 110, a timer and switch setting circuit 111, a discrimination circuit 112, and a control word decoding means 113.

A feature of the present invention is that the input/output control device 100 includes a timer and switch circuit 111, a discriminating circuit 112, and a control word decoding means 113, which receive and discriminate a message control word and then open the transmission path for a predetermined period of time. It is designed to switch over and return to its original state after a predetermined period of time.

Next, the operation of this embodiment will be explained.

The transceiver 101 and the transceiver 102 receive the output of the encoder 103, which has been converted from parallel to serial data, via the control line 3, and send the serial data to each transmission line +1) l and transmission line (2) 2. I can do it.

Furthermore, data from the transmission lines (1) 1 and (2) 2 are sent to the control line 4 via the transceiver 101 and the transceiver 102, respectively, to the decoder 104 and the decoder 105, respectively.
and sent through 5. Each buffer circuit 107 and 109 has a buffering capacity of at least one word after converting serial data into word data, and receives the outputs of decoders 104 and 105 via control lines 6 and 7, respectively.

Error detection selection circuit 108 connects decoders 104 and 10
5 is checked for errors, and if an error occurs, the switch circuits 110 are set to the yarn paths on the opposite side, and if the message requests a status response, the message is read by the control word decoding means and sent to the status response means. 10
6 cents and output by the encoder 103,
A status response is output to transmission line (1) 1 and transmission line (2) 2.

When the control word decoding means 113 receives data from the transmission line via the control line 12 as a message control word and a transmission line switching command is sent in the test mode, the control word decoding means 113 decodes the contents and decodes the data from the transmission line via the control line 14. The specified transmission path data is output to the discrimination circuit 112.

The control circuit 112 uses this specified transmission line data and the control line 13.
Compare with the currently connected transmission line data input via
If the designated transmission line is different from the currently connected transmission line, control the output!
15 to the timer and switch setting circuit 111.

The timer and switch setting circuit 111 is a discriminator circuit 11
By the input from 2, only the time of the set timer value,
The switch circuit 110 is controlled via the control line 16 to switch the connection of the currently connected transmission line to the designated transmission line, and to return to the original connection after the timer value elapses.

That is, according to this embodiment, in the test mode, data with errors for switching is sent to the currently connected transmission line, and
When switching to another transmission line, offline T&D or online T&D can be performed to detect the quality of the line. During normal operation, a switching command is not sent as a message control word, so the timer circuit does not operate, and if an error occurs in the currently connected transmission line, normal operation continues with switching to another transmission line. .

FIG. 2 shows a system diagram to which the present invention is applied, and is configured by connecting n input/output control devices 100 shown in FIG. 1 to transmission line (1) 1 and transmission line (2) 2. be done.

〔Effect of the invention〕

As explained above, in the present invention, in the test mode, the serial data transmission path is controlled to be switched only for a predetermined period of time, and to return to the original state after a predetermined period of time has elapsed. By testing the condition of the transmission line during maintenance and repairing it in advance if it is defective, preventive maintenance, which was previously impossible, can be carried out.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. Figure 2 is the system diagram. l... Serial data transmission line (1), 2... Serial data transmission line (2), 3-18... Control line, 100
... Input/output control device, 101.102... Transmitter/receiver, 103... Encoder, 104.105... Decoder, 106... Status response means, 107.10
9... Buffer circuit, 108... Error detection selection circuit, 11Q... Switch circuit, 111... Timer and switch setting circuit, 112... Discrimination circuit, 113
..., control word decoding means. Patent Applicant: NEC Corporation, Agent: Patent Attorney Nao Takashi Ide:. Example block diagram 151

Claims (1)

[Claims] (1) Send the same data to two serial data transmission paths at the same time, receive this data only from one of the transmission paths, and if an error occurs during data reception, the data will be sent to the other transmission path. In a serial data transmission line switching control method that controls automatic switching, the transmission line is switched only for a predetermined period of time during test mode, and the switching is returned to its original state after a predetermined period of time has elapsed. A serial data transmission path switching control method characterized by: