JPH079465Y2 - LAN interface - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to an interface for a local area network (LAN), and more particularly to a transmission line separation circuit of a duplicated transmission line.

B. Outline of the Invention In the LAN system in which each module has a redundant transmission line and a LAN interface for connection between the modules, the present invention eliminates transmission line disconnection due to computer failure of each module.
By performing sequential control with a period required for system restructuring of the 1st and 2nd systems, the data transmission unavailable period is eliminated due to the disconnection of the module even when there is a computer error.

C. prior art LAN system, in order to improve the reliability of the information communication between multiple computers, for example, as shown in FIG. 2, duplexed transmission line 1 _1, 1 ₂ provided the computer 2 ₁ to 2 It is a bus connection method in which _n is connected in parallel. Interface 3 ₁ to 3 _n each comes when there is data to be transmitted to each computer 2 ₁ to 2 _n performs data transmission to the interface of the destination computer by performing a predetermined procedure, data from the receiver interface to the computer Transfer.

Interface 3 ₁ to 3 _1, as representatively shown in the 3 _1,
A LAN controller 4 having a protocol family in advance so that data can be transmitted / received in accordance with an access control method such as a polling method or a token bus method, and a transceiver 5 for performing transmission / reception with matching with a transmission path and waveform processing. These interfaces 3 ₁ to _n are duplicated transmission lines 1 ₁ ,
1 and ₂ are provided with dedicated controllers 4 and transceivers 5, respectively, and computers 2 ₁ to 2 _n or dedicated processors use the other transmission line 1 ₂ or 1 ₁ to transmit data if one transmission line 1 ₁ or 1 ₂ fails. Secure a route.

As the LAN controller 4, for example, SMC (STANDARD M
There is a COM9026 LAN LSI manufactured by ICROSYSTEMS CORPORATION), and this controller performs transmission and reception of data packets by establishing the transmission right that avoids data collision due to tone passing and confirming the acknowledge from the destination, and the abnormality in the transmission line. When an event occurs or a node is added or deleted, a time zone (0.8 to 0.9 seconds) during which data transfer cannot be executed, called reconfiguration, is created to reconstruct the network of the transmission line, and a new node number is created. Rebuild the system.

D. Problems to be solved by the device In a conventional LAN system with a redundant transmission line, LAN interfaces 3 _{1 to} 3 _n perform data transfer for a certain period of time in order to rebuild the transmission line network when an abnormality occurs in the transmission line. Disable At this time, the transmission line 1 _1, 1 ₂ so as not simultaneously disables data transfer on both systems, the computer 2 ₁ ~
2 _n or a dedicated processor controls the program.

However, if a computer or dedicated processor fails and program control becomes impossible, the transmission path cannot be switched to disconnect the module from the system, and data transmission between other modules during reconfiguration is not possible. It becomes impossible.

If the LAN controller 4 is COM9026 and it is normal, the token controller can only input / output token data even if there is a problem on the computer side. It does not become an input / output obstacle between them. However, if the power supply is turned off to replace the defective module with a normal module, the function of the LAN controller of the module is lost and data transfer becomes impossible.

An object of the present invention is to provide an interface for LAN that can secure data transfer even when a problem occurs on the computer side.

E. Means and Actions for Solving the Problem In order to achieve the above-mentioned object, the present invention connects the 1-system and 2-system interfaces, each of which is a combination of a LAN controller and a transceiver, to a duplicated transmission line to provide the LAN connection. The controller disconnects the abnormal module from the system by generating a transmission prohibition period due to an abnormal information transmission between modules.
In a LAN interface having a configuration function, a watchdog timer for detecting a computer abnormality of each module, and a reset state when the computer is normal, and a set state when the timer detects a computer abnormality Flip-flop, a first AND gate for suppressing transmission signal output from the 1-system LAN controller when the first flip-flop is in the set state, and the first flip-flop is in the set state. From the time it became
A timer that obtains a time-up output when the time required for configuration is exceeded, and a second flip-flop that is set when the first flip-flop enters a set state and that is reset by the time-up output of the timer. And a second AND gate that enables the transmission signal output from the LAN controller for the second system only while the second flip-flop is in the set state, and monitors the occurrence of a computer abnormality by the watchdog timer. Then, in place of the computer, the first and second occurrences of the abnormality occur.
The transfer function by the interface of the 2 system during the reconfiguration period of the 1 system by switching the transmission path from the 1 system to the 2 system by the gate means including the flip-flop, the timer and the first and second AND gates. , The transmission between other modules is restarted in the reconstructed system of 1 system at the end of the period, the reconfiguration of the 2 system is performed with the transmission function of the 2 system suppressed, and the disconnection of the module is completed. .

F. Embodiment FIG. 1 is a transmission line disconnecting circuit diagram showing an embodiment of the present invention. This transmission line disconnection circuit diagram is provided between the LAN controller 4 and the transceiver 5 in FIG.
1 and TX2 represents transmission signals from one system and the system 2 respectively controller 4,4, signal WD computer 2 ₁ of each module
_2n Watchdog trigger signal. Watchdog
The timer 11 is triggered by a watchdog trigger signal on the computer side to start clocking, and detects an abnormality on the computer side when the next trigger signal is not given before the count up. The D-type flip-flop 12 is provided with a logic "1" at the D input, and stores the abnormality on the computer side as a set state by using the count-up signal of the timer 11 as a clock input. The AND gate 13 receives the Q output of the flip-flop 12 as a gate input, validates the signal TX1 in its reset state, and outputs the signal TX1 as a transmission signal to the transceiver side.

The timer 14 receives the output of the flip-flop 12 as a trigger input and is triggered in the set state to start time measurement, and obtains an output by measuring time longer than the time required for reconfiguration of the transmission path. The flip-flop 15 opens the gate input of the AND gate 16 in the set state of the flip-flop 12, and closes the gate of the gate 16 with the time-up output of the timer 14. The AND gate 16 enables the signal TX2 by opening the gate, and outputs the signal TX2 as a transmission signal to the transceiver side.

By providing such a transmission line disconnection circuit diagram, the flip-flop 12 is normally reset (initial reset), the signal TX1 from the LAN controller of the 1-system is sent to the transmission line through the gate 13, and the 1-system Communication between modules is performed. When an abnormality occurs on the computer side, the watchdog timer 11 counts up, sets the flip-flop 12 in the set state, closes the gate of the gate 13, and opens the gate of the gate 16 by setting the flip-flop 15 to open the system 2 The signal TX2 from the LAN controller is sent to the transmission line. At this time, each LAN controller for each module starts reconfiguration of the 1-system as a transmission error in the 1-system, and rebuilds the system by disconnecting the 1-system from the transmission path.
During this period, the transmission function of the two systems ensures the data transmission function with the computer abnormal module.

Next, after the reconfiguration of system 1 is completed, the timer
14 counts up, the gate 16 is closed by the flip-flop 15, and the reconfiguration of the second system is started by suppressing the output of the signal TX2 of the second system transmission circuit.
The system is also separated from the system.

Therefore, when a computer error occurs in a module, reconfiguration is not performed simultaneously for the 1st system and the 2nd system to disconnect the module from the system.
By the transmission disconnection in which the system and the system 2 are sequentially disconnected, the abnormal module can be automatically disconnected without losing the inter-module data transmission function.

G. Effect of the Invention As described above, according to the present invention, a computer error occurs in a system configuration in which a LAN interface for transmitting information between modules by a redundant transmission path has a transmission prohibition period for system reconstruction. Since the 1-system and the 2-system are automatically switched sequentially with a time lag longer than the transmission prohibition period and both systems are disconnected from the transmission path respectively, transmission switching and disconnection are automatically performed even when there is a computer error. It is possible to perform disconnection between the other modules while eliminating the non-transmission period.

[Brief description of drawings]

FIG. 1 is a transmission line separation circuit diagram showing an embodiment of the present invention, and FIG. 2 is a network configuration diagram with a duplicated transmission line. 1 ₁ , 1 ₂ ... Transmission line, 2 ₁ , 2 _n ... Computer, 3 ₁ , 3 _n ... LAN interface, 4 ... LAN controller, 5 ... Transceiver, 11 ... Watchdog timer, 12,15 ... Flip-flop, 14 ... Timer.

Claims (1)

[Scope of utility model registration request] 1. A 1-system and 2-system interface, which is a set of a LAN controller and a transceiver, are respectively connected to a duplicated transmission line, and the LAN controller generates a transmission prohibition period due to an abnormal information transmission between modules. In the LAN interface that has a reconfiguration function that disconnects the abnormal module from the system, a watchdog timer (11) that detects an abnormality in the computer of each module and the timer that is reset when the computer is normal A first flip-flop (12) that is set when an abnormality is detected, and a first flip-flop that suppresses transmission signal output from the 1-system LAN controller when the first flip-flop is set 1 AND gate (13) and the first flip-flop are set A timer (14) that obtains a time-up output when the time required for the reconfiguration exceeds the time required for the reconfiguration, and a timer (14) that is set when the first flip-flop enters the set state. A second flip-flop (15) that is reset by an up output, and a second AND gate (15) that validates the transmission signal output from the 2-system LAN controller only while the second flip-flop is in the set state. 16), and a LAN interface characterized by.