JPH02231835A - Node fault detector - Google Patents

Abstract

PURPOSE:To prevent a transmission system from being in system-down when a fault sending a data to a bus continuously takes place in a specific node by measuring the transmission time of a transmission carrier and stopping the data transmission from a data transmission section when the time exceeds a prescribed time. CONSTITUTION:A transmission carrier detection section 13 monitors the state of a bus 2 and the state of a data transmission section 10 and when the presence of a carrier in the both is detected, it is discriminated that its own node sends the transmission carrier and a detection signal is sent to a timer 14. When a fault sending a packet data continuously from the data transmission section 10 of the node 1 to the bus 2 takes place and the consecutive time exceeds a prescribed time, the timer 14 invalidates a generated data transmission section control signal and gives an input to an OR circuit 15. Thus, the data transmission section control signal sent from the OR circuit 15 to the data transmission section 10 is invalidated and the data transmission section 10 stops the transmission of a packet data.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a node failure detection device for detecting node failure in a bus-type communication network system.

[Conventional technology]

FIG. 4 is a node configuration diagram showing a conventional node failure detection device disclosed in, for example, Japanese Unexamined Patent Publication No. 61-208333. In the figure, 1 is a node and 2 is this node 1
A bus is a bus that connects a plurality of buses to form a bus-type communication network system shown in FIG. 3 is a data decoding unit that decodes the packet data received from the bus 2; 4 is a data buffer that stores the packet data decoded by the data decoding unit 3; and 5 is a data buffer that stores the packet data decoded by the data decoding unit 3. This is an address/data length recognition unit that confirms the data length. 6 is the data decoding section 3 or address/data length recognition section 5
7 is a display section that displays the abnormality detected by the display section 6, and 7 is a display control section that controls the display of the display section 6. Reference numeral 8 denotes a local station packet control unit that receives and controls the transfer of packet data addressed to the local node stored in the data buffer 4 when no abnormality is detected in the address/data length recognition unit 5. be. Next, the operation will be explained. Each node 1 takes in all packet data transmitted on the bus 2 regardless of the destination address and inputs it to the data decoding section 3. Here, this packet data is encoded into a special code such as a Manchester code so that an error does not occur due to continuous "0" or "1" in the input signal, and is further encoded with a destination address DA1, a source address SA, and a data length DL. , data DATA, and frame check sequence FCS, which are transmitted on the bus 2 in the format shown in FIG. The data decoding section 3 decodes the input packet data from the special code to the original packet data, stores it in the data buffer 4, and inputs it to the address/data length recognition section 5. In the address/data length recognition section 5,
The data length of the input packet data is measured and compared with the data length DL in the packet data stored in the data huffer 4. As a result, if the data length of the input packet data is abnormally long or short, the originating address in the packet data stored in the data buffer 4 is detected and the faulty node
is notified to the display control unit 7. The display control section 7 controls the display on the display section 6 based on the input signal. If the data is normal, the packet data stored in the data huffer 4 is discarded and the next input packet data is stored. At this time, if the stored packet data is addressed to the own node, the packet data stored in the data buffer 4 is transferred to the own node packet control unit 8.

[Problem to be solved by the invention]

Conventional node failure detection devices are configured as described above, so the sending address SA, data length DL, etc. are required to detect a node failure, and if an abnormality occurs that prevents them from being received, the failure is detected. Detection is impossible, and even if an abnormality is detected, other nodes 1 will not be able to send packet data until Lotus 2 is empty, resulting in the transmission system going into a system down state. There was a point. This invention was made to solve the above problems, and prevents the transmission system from going down even if an abnormality occurs such as a specific node continuing to send packet data to the bus. The purpose of this study is to obtain a node failure detection device that realizes a fail-soft transmission system.

[Means to solve the problem]

The node failure detection device according to the present invention includes a transmission carrier detection unit that detects that the transmission carrier of its own node is being transmitted, and a transmission carrier detection unit that measures the transmission time of the transmission carrier, and when the transmission time exceeds a certain time, A timer is provided to generate a data transmitter control signal to stop data transmission from the data transmitter.

[Effect]

The transmission carrier detection section in this invention detects whether the transmission carrier of its own node is being sent out from the state on the bus and the state of the data transmission section, and the timer detects the transmission detected by the transmission carrier detection section. Measure the carrier sending time, and if the sending time exceeds a certain time,
Generates a data transmitter control signal that stops data transmission from the data transmitter.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a node, and 2 is a bus, which constitutes the bus-type communication network system shown in FIG. 2, similar to the conventional systems, and packet data having the format shown in FIG. 3 is transmitted. 10 sends packet data encoded into a predetermined code to bus 2.
11 is a data receiving section that receives packet data from the bus 2, and 12 is a transmission/reception control section that controls the data transmitting section 10 and the data receiving section 11. 13 indicates the status of bus 2 and data transmitter 1
14 is a transmission carrier detection unit that detects that the transmission carrier of its own node is being transmitted from the state of 0, and 14 measures the transmission time of the transmission carrier detected by this transmission carrier detection unit, and calculates the transmission time. This is a timer that generates a data transmitter control signal when the time exceeds a certain time. 15 is configured to automatically output a data transmitting unit control signal when either the data transmitting unit control signal from this timer 14 or the data transmitting unit control signal generated when the transmission/reception control unit 12 detects an abnormality becomes involuntary. This is an OR circuit that stops the data transmitter 10 from transmitting packet data. Next, the operation will be explained. If the data transmitter control signal from the OR circuit 15 is significant, the data transmitter 10 transmits packet data encoded in a predetermined code when the bus 2 is free under the control of the transmitter/receiver controller 12. . At this time, the transmission carrier detection unit 13 monitors the status of the lotus 2 and the status of the data transmission unit 10, and if it detects that there is a carrier in both, it is assumed that the own node is transmitting the transmission carrier. Send the detection signal to the timer 14. Here, if an abnormality occurs such that the data transmitter 10 of node 1 continues to send packet data to lotus 2,
The duration of the detection signal generated by the transmission carrier detection section 13 is long. The timer 14 measures the duration of this input detection signal, and when the duration becomes longer than a predetermined fixed time, the timer 14 involuntarily outputs the generated data transmitter control signal to the OR circuit 15. input. Therefore, the data transmitter control signal sent from this OR circuit 15 to the data transmitter 10 also becomes meaningless, and the data transmitter 10
stops sending packet data. Additionally, the timer 14 simultaneously sends an abnormality notification signal to the transmission/reception control unit 12 to inform it of the occurrence of an abnormality. Transmission/reception control section 12
When receiving this abnormality notification signal, it disables the data transmitter control signal to the OR circuit 15, disables the data transmitter control signal output from the OR circuit 15, and transmits the packet data from the data transmitter 10. to stop. In monitoring the status of the lotus 2 and the status of the data transmitting unit 10, the transmitting carrier detecting unit 13 detects that there is a carrier transmitted from the data transmitting unit 10 but there is no carrier on the bus 2, and detects that there is no carrier on the bus 2. An abnormality notification signal is sent to the transmission/reception control unit 12 indicating that an abnormality has occurred. Upon receiving this abnormality notification signal, the transmission/reception control section 12 disables the data transmission section control signal sent to the OR circuit 15. Therefore, the data transmitting unit control signal outputted from the OR circuit 15 to the data transmitting unit 10 becomes meaningless, and the data transmitting unit 10 stops sending out packet data.

【Effect of the invention】

As described above, according to the present invention, it is detected that the transmission carrier of its own node is being transmitted, and the timer measures the transmission time of the transmission carrier detected by the transmission carrier detection unit, and the timer measures the transmission time of the transmission carrier detected by the transmission carrier detection unit, and the timer measures the transmission time of the transmission carrier detected by the transmission carrier detection unit. The configuration is configured to generate a data transmitter control signal that stops data transmission from the data transmitter when the time exceeds , so even if an abnormality occurs such as a particular node continuing to transmit data, This has the effect of providing a node failure detection device that can prevent the transmission system from going down and realize a fail-soft transmission system.

[Brief explanation of the drawing]

FIG. 1 is a node configuration diagram showing a node failure detection device according to an embodiment of the present invention, FIG. 2 is a configuration diagram showing a bus-type communication network system to which this invention is applied, and FIG. FIG. 4 is an explanatory diagram showing an example of the format of packets exchanged in a network system, and FIG. 4 is a node configuration diagram showing a conventional node failure detection device. 1 is a node, 2 is a lotus, 10 is a data transmission section, 11 is a data reception section, 12 is a transmission/reception control section, 13 is a transmission carrier detection section, and 14 is a timer. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A plurality of nodes are connected to the bus, each of which includes a data transmitter that sends data to the bus, a data receiver that receives data from the bus, and a transmission/reception controller that controls the data transmitter and the data receiver. , in a node failure detection device for detecting a failure of the node in a bus-type communication network system in which each node sends data from the data transmission unit when the bus is free, the node failure detection device detects a failure of the node; From the state of 1. A node failure detection device comprising: a timer that generates a data transmitter control signal that stops data transmission from the data transmitter when the data exceeds the data transmitter.