JPS61208333A - Node fault detecting system - Google Patents

Abstract

PURPOSE:To facilitate supervision of a fault of a slave station by detecting a node failure of a network by the detection of data length. CONSTITUTION:A master station fetches all packets of format on a bus independently of a destination address. A data decoding section 5' is a decoder recovering the data encoded to a specific code such as Manchester code into the original form so that no error is produced because of consecutive 0s or 1s of the input signal. If consecutive 0s or 1s exist in the input signal inputted to the decoder, it is informed to a display control section 7 of a fault notice section 3 as a fault signal and displayed on a display section 8. An address data length recognizing section 1 measures the data length of the input packet, compares it with the data length DS described in a packet and when the data length is longer or shorter abnormally, the sender address SA is detected from the data recorded in the data buffer 2, the node having an error is informed to a fault notice section 3 and the signal inputted by a display control section 7 gives a display on the display device of the display section 8.

Description

[Detailed Description of the Invention] [Summary] In a master station device of a bus network, for the purpose of monitoring abnormalities in slave stations, the master station captures all data flowing to the node and monitors the packet length. This makes it possible to detect abnormalities in the slave station.

[Field of Industrial Application] The present invention relates to a node failure monitoring system in a bus-type communication network system among communication network systems. □In recent years, bus-type communication network systems have been widely used to reduce costs in communication network systems. In this bus-type communication network, when using the so-called C3MA/CD method, which is generally well known and accesses by detecting the vacant state of the bus, as a method of accessing the transmission path, it is possible to efficiently prevent slave station abnormalities. There is a need for a means for detecting failures that can be detected accurately.

[Prior art and problems to be solved by the invention] A conventional example of the present invention will be explained in detail with reference to the drawings.

FIG. 4 is a diagram showing a conventional example of the present invention, in which 11, 12 and 13 indicate nodes, and 2 indicates a bus.

In a bus-type network system, when nodes 11.12.13 connected to bus 2 send data to bus 2 using the C3MA/CD method for transmission, check the usage status of the bus and check whether bus 2 is free or not. (No other node is transmitting data), the own node starts data transmission. This method has the disadvantage that if an abnormality occurs in which a certain node continues to send data to the bus, other nodes will be unable to send data unless the bus becomes empty, resulting in a system down state.

[Means for solving problems]

FIG. 1 shows a principle block diagram of the node failure detection method of the present invention. In FIG. 1, in a bus-type communication network system, all data flowing on the bus 2 is sent to the data receiving unit 5.
The monitoring unit 6 monitors the data length, determines which node in the network is the node that caused the failure, and notifies the error communication unit 3.

[Effect]

The monitoring unit 6 captures and stores all the data flowing on the bus, and at the same time detects the length of the packet.

If the packet length is abnormally long, the address is found based on the stored data and the abnormality notification unit 3 is notified of the node where the failure has occurred.

〔Example] Embodiments of the present invention will be described in detail using the drawings.

FIG. 2 is a block diagram of a master station for explaining an embodiment of the present invention, in which 1 is an address data length recognition unit, 2 is a data buffer, 3 is an abnormality notification unit, and 4 is a local station packet control unit. 5' indicates a data decoding section, and 6 indicates a packet monitoring section. Also, FIG. 3 shows the format of a packet used in the present invention, which is a DA taxi sequence.

In the present invention, the master station captures all packets in the format shown in FIG. 3 flowing on the bus, regardless of the destination address.

The captured packet is input to the data decoding section.

The data decoding unit 5' is a decoder that reproduces data encoded into a special code such as a Manchester code into its original form so that errors do not occur due to consecutive zeros or consecutive ones in the input signal. If the input signal input to this decoder has consecutive zeros or l, it is notified as an abnormal signal to the display control section 7 of the abnormality notification section 3 and displayed on the display section 8.

Other than the above, the input signal is reproduced and inputted to the address/data length recognition section 1 and data buffer 2 inside the packet monitoring section 6'.

The address/data length recognition unit 1 measures the data length of the input packet and compares it with the data length DS written in the packet.If the data length is abnormally long or short, the data buffer 2 The abnormality notification unit 3 detects the originating address SA from the data recorded in Figure 3 as shown in Figure 3.
The node that has caused the failure is notified to the node, and the display is displayed on the display unit 8 based on the signal input to the display control unit 7.

If the data is normal, the data input to the data buffer is discarded and the next data is input.

Further, the data sent to the local node is input to the local packet control unit 4 when the data is normal in the monitoring unit 6.

〔Effect of the invention〕

As described above, according to the present invention, node failures in the network are detected by detecting the data length, making it possible to easily monitor abnormalities in slave stations.

[Brief explanation of the drawing]

FIG. 1 is a principle block diagram of the node failure detection method of the present invention, FIG. 2 is a diagram for explaining an embodiment of the present invention, and FIG.
The figure shows an example of a packet format, and FIG. 4 shows a diagram for explaining a conventional example. In the figure, 1 is an address data length recognition unit, 2 is a data buffer, 3 is an abnormality notification unit, 4 is a local packet control unit,
5 is a data receiving section, 5' is a data decoding section, and 6 is a monitoring section. 7 is a bus, 8 is a display control unit, 9 is a display unit 11, 12.1
3 indicates each node. Hara [)” O-rig diagram vI l Jin] Implementation of non-invention 49'1 Jti 70-knob 4th
2 Concave DA: Destination 7 dress, SA: 9 㷲 7 ト "°shisu OL:
Data: Data Fe3: Frame Senku/'Noxique) Spake/
[Example No. 312] Conventional row [Illustration for explanation] Fig. 4

Claims (1)

[Scope of Claims] A bus-type communication network system in which a plurality of nodes are connected to a bus and transmit data when the bus is idle, comprising: a data receiving unit that receives all the data flowing on the bus; A node failure detection method, comprising: a monitoring section that detects an abnormal node by measuring the data length of data received by the data receiving section.