JP2615969B2 - Automatic / manual control channel switch circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Control mode from automatic control to manual control, which relates to a duplex loop type local area network, and particularly to a switching circuit for switching to a spare channel due to a failure during operation of a working channel The purpose of the present invention is to provide a switching circuit that performs switching effectively, in which a failure occurs in a working channel of a duplicated loop-type local area network and switches to a protection channel, and only when a manual mode is controlled by a manual switch. An effective channel select switch, an automatic mode effective when controlled by an externally connected network service processor, an automatic / manual changeover switch for switching between the manual modes, and an automatic mode controlled and automatically controlled by the network service processor. / Manual selector switch is in automatic mode An automatic channel switching device that is effective only when the automatic / manual switching switch is in the automatic mode, and a selector for selecting control by the automatic channel switching device when the automatic / manual switching switch is in the manual mode, and selecting control by a channel selector switch when the automatic / manual switching switch is in the manual mode. Providing a latching relay for latching the control mode in the automatic mode and the manual mode selected in the above, when performing a channel switch from the working channel to the spare channel in the state latched by the latching relay, from the automatic mode, The configuration is such that inadvertent channel switching that occurs when switching control to the manual mode is prevented.

[Industrial applications]

The present invention relates to a dual-loop local area network, and more particularly to a switching circuit for switching to a protection channel when a failure occurs during operation of a working channel.

[Conventional technology]

FIG. 2 is a diagram showing a channel switching method in a dual loop LAN.

In the communication by the duplex loop type LAN as shown in FIG. 2, a master station 12 is controlled by a network service processor 11 which controls the system, and the master station 12 has stations A, B and 14, 15, and 16. , C, etc., respectively. That is, 14, 1
Station A, Station B of each of 5, 16
The station C is connected in a loop to form a network, and a so-called token 19 and data 20 are circulated on a channel to transfer data to a desired destination. Then, from the working channel 17 to the protection channel 18 due to the failure occurrence
The system switching to is performed by using the system switching circuit 13.

FIG. 3 is a diagram showing the configuration of a conventional system switching circuit shown as 13 in FIG.

In the figure, reference numeral 1 denotes a channel select switch, which performs an effective operation only when the control is in a manual mode without control from the network service processor 11, and 2 denotes an automatic / manual changeover switch. An automatic channel switching device, which switches between automatic mode and manual mode control, is controlled by the network service processor 11, and is effective only when the control by the automatic / manual switch 2 is in the automatic mode. Reference numeral 4 denotes a selector, which selects the channel select switch 1 or the automatic channel switching device 3 according to the mode setting of the automatic / manual switch 3 in the automatic mode or the manual mode. Reference numeral 6 denotes a system changeover switch for switching the system between the working channel 17 and the protection channel 18 based on the output of the selector 4.

In a normal operation, when the automatic / manual changeover switch 2 is in the manual mode, the operation is performed such that the effective channel follows only the instruction of the channel selector 1 and the instruction of the automatic channel switching device 3 becomes invalid. On the other hand, when the automatic / manual changeover switch 2 is in the automatic mode, the effective channel operates only in accordance with the instruction of the automatic channel switching device 3 and the instruction of the channel select switch 1 is invalidated.

In the redundant loop type LAN switched as described above, for example, when the active channel 17 is operated by selecting the automatic / manual switch 2 of the system switching circuit 13 to operate in the automatic mode, It is assumed that the state is switched to the spare channel 18 due to the occurrence of the failure, and that the operation is normally started on the spare channel 18 thereafter.
At this point, if the control in the automatic mode is inadvertently switched to the control in the manual mode because of some reason, the failure mode network will be selected if the switch in the manual mode indicates the working channel 18. Inconvenience will occur.

However, it works well when the switch in the manual mode is pointing to the backup channel 18, and there is no inconvenience in switching.

That is, for example, in the case where the control from the automatic mode as described above is inadvertently switched to the control in the manual mode, the state before the switching disappears and the state after the switching is not carried over to the state after the switching. A problem occurs in the control, and the problem causes a system down.

[Problems to be solved by the invention]

Therefore, when switching from the working channel to the protection channel carelessly, there is a problem that switching between the working channel and the protection channel may be inconvenient depending on the selection of the automatic / manual switch.

An object of the present invention is to provide a switching circuit that effectively switches a control mode from automatic control to manual control.

[Means for solving the problem]

 FIG. 1 is a diagram showing the principle configuration of the present invention.

In the figure, 1 is a channel select switch, which is effective only in a manual mode controlled by a manual switch, and 2 is an automatic / manual changeover switch, which is controlled by an externally connected network service processor. An automatic channel switching device which switches between an effective automatic mode and the manual mode; 3 is an automatic channel switching device which is controlled by the network service processor and which is effective only when the automatic / manual switching switch 2 is in the automatic mode;
Reference numeral 4 denotes a selector, which selects control by the automatic channel switching device 3 when the automatic / manual changeover switch 2 is in the automatic mode, and selects control by the channel selector switch 1 when the automatic / manual changeover switch 2 is in the manual mode. It is a relay for latching the control state in the automatic mode and the manual mode selected by the selector 4.

In this latching relay 5, the previous control state is always latched so as to control the system changeover switch 6, thereby preventing inadvertent channel switching that occurs when switching the channel from the working channel 17 to the standby channel 18. It is configured so that

(Operation)

In the present invention, as shown in FIG. 1, the output of the channel select switch 1 that is valid only when the channel switching mode is the manual mode, and the output of the automatic channel switching device 3 that is valid only when the channel switching mode is the automatic mode. Are respectively applied to the selectors 4, and these outputs are selected by the automatic / manual changeover switch 2 so as to be latched by the latching relay 5.

Therefore, when the control is switched from the automatic mode to the manual mode, since the immediately preceding state is always stored in the latching relay 5, it is possible to perform switching without causing a failure when switching between the working channel and the protection channel. Becomes

〔Example〕

FIG. 1 is a diagram showing a configuration of a system switching circuit of the present invention. In the figure, 1, 2, 3, 4, and 6 are the same as those of the conventional system switching circuit shown in FIG. 3, and 5 is a latching relay added in the present invention.

That is, 1 is a channel select switch, 2 is an automatic / manual switch, 3 is an automatic channel switch, and 4 is a selector. Reference numeral 5 denotes a latching relay for latching the channel signal selected by the selector 4, and reference numeral 6 denotes a system changeover switch, which switches the system of the working channel and the protection channel by the channel signal latched by the latching relay 5. Switch to do.

In a normal operation, when the automatic / manual changeover switch 2 is a manual switch, the effective channel operates in accordance with the instruction of the channel selector 1 and the instruction of the automatic channel switching device 3 becomes invalid. On the other hand, when the automatic / manual changeover switch 2 is an automatic switch, the operation is performed in such a manner that the effective channel follows the instruction of the automatic channel switching device 3 and the instruction of the channel select switch 1 is invalidated as in the conventional example. is there.

However, when the system switching circuit of the present invention is used, the state when the automatic / manual switch 2 is switched during operation and the state when the power is switched on / off are as follows.

1. At the time of switching of the automatic / manual switch 2 When the mode is switched from the automatic mode to the manual mode, the valid channel is held by the latching relay 5 in a state before the switching, and inherits the state of the channel at the time of the automatic operation.

When the mode is switched from the manual mode to the automatic mode, the valid channel follows the instruction of the automatic channel switching device, and if there is no instruction from the automatic channel switching device 3, the state in the manual mode is held by the latching relay 5.

2. Status at power on / off switching When the status of the automatic / manual switch 2 is in the automatic mode,
The effective channel follows the instruction of the automatic channel switching device 3,
If there is no instruction from the automatic channel switching device, the state in the manual mode is maintained by the latching relay 5.

When the automatic / manual changeover switch 2 is in the manual mode,
The valid channel holds the state before the power is turned on / off, and follows the instruction of the channel before the power is turned on / off by the latching relay 5.

When the power is turned on / off, the latching relay 5 holds the state of the channel before the power is turned off in all cases.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the state before the switching is always held by using the latching relay, so that the system switch can be switched from the automatic mode to the manual mode, and the power supply can be switched. Even when switching from ON to OFF, it is no longer possible to operate a channel in which a failure has occurred by mistake, and this greatly contributes to improving the performance of a duplex loop LAN.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a system switching circuit of the present invention, FIG. 2 is a diagram showing a channel switching method in a duplex loop LAN, and FIG. 3 is a diagram showing a configuration of a conventional channel switching circuit. . In the figure, 1 is a channel select switch, 2 is an automatic / manual switch, 3 is an automatic channel switch, 4 is a selector, 5 is a latching relay, and 6 is a system switch.

 ────────────────────────────────────────────────── (5) References JP-A-58-7951 (JP, A) JP-A-58-117794 (JP, A) JP-A-61-26156 (JP, A) JP-A-61-26156 224757 (JP, A)

Claims (1)

(57) [Claims] 1. A channel select switch (1) which is effective only in a manual mode controlled by a manual switch, wherein a failure occurs in a working channel of a duplicated loop type local area network and switches to a spare channel. An automatic mode effective when controlled by an externally connected network service processor, an automatic / manual switch (2) for switching between the manual modes, controlled by the network service processor,
And an automatic channel switching device (3) effective only when the automatic / manual changeover switch (2) is in the automatic mode, and a control by the automatic channel changer (3) when the automatic / manual changeover switch (2) is in the automatic mode. Selected,
And a selector (4) for selecting control by the channel selector switch (1) when in the manual mode; and a latching relay (5) for latching a control state in the automatic mode and the manual mode selected by the selector (4). When switching the system changeover switch (6) from the working channel (17) to the spare channel (18) in the state of being latched by the latching relay (5), and when switching control from the automatic mode to the manual mode. An automatic / manual control channel changeover switch circuit for preventing inadvertent channel change that occurs.