JPH11341108A - Switching method and device of active system and standby system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the accurate switching of an active system and a standby system in a redundant constitution system. SOLUTION: First input terminals 14 and 16 of respective active system and standby system switching devices 6 and 8 are connected with second input terminals of all the other active system and standby system switching devices. The active system and standby system switching device 6(8) provided in the system 2(4) includes a first pre-differentiation circuit 18, a second pre- differentiation circuit 20, and a JK flip flop circuit for receiving a switching pulse 10 through the input terminal 14(16). This JK flip flop circuit makes an output 24 of the first pre-differentiation circuit 18 into a J input, and an output 26 of the second pre-differentiation circuit 20 into a K input.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active / standby system switching method and a switching apparatus for switching between an active system and a standby system in a plurality of redundantly configured systems.

[0002]

2. Description of the Related Art In a plurality of redundantly configured systems, it is necessary to provide setting information for setting any one of an active system and a standby system to any system. If such setting information does not exist, confusion arises such that the only active system appears redundantly or all the systems become standby systems, and the redundant configuration system does not function effectively. Therefore, conventionally, a register provided in both a system to be separated from the redundant configuration system due to a failure or the like and a standby system to be the next active system and holding system setting information (indicating that the system is active or standby) is stored in a register. By accessing and rewriting the setting information of this register, the former is switched from the active system to the standby system, and the latter is switched from the standby system to the active system.

[0003]

However, since it was necessary to access both registers, it took time to switch. Even if the system itself does not fail, if the register that holds the setting information of the system (to indicate that it is working or spare) fails, the system is eventually changed from the working system to the spare system or from the spare system to the working system. When switching, reliable switching could not be performed, causing problems such as duplicate appearance of the active system and disappearance of the active system.

An object of the present invention is to provide a method for switching between an active system and a standby system and a switching apparatus which can reliably switch between the active system and the standby system.

[0005]

According to the present invention, in order to solve the above-mentioned problem, each of a plurality of redundantly configured systems is provided with an active system / standby system switching device. The first input terminal of each of these devices is connected to the second input terminal of each of the other devices. These devices have a first input terminal, a second input terminal, and switching control means connected to the first and second input terminals.

The switching control means includes a first pre-differentiating means connected to the first input terminal, a second pre-differentiating means connected to the second input terminal, and a first and second pre-differentiating means. A two-state device connected to the means.

[0007] The first and second pre-differentiating means respectively
A first signal delay unit connected to the first or second input terminal, a second signal delay unit connected in series to the first signal delay unit, an output terminal of the first signal delay unit, AND logic means connected to the output terminal of the second signal delay means.

According to the present invention, when switching one of a plurality of redundantly configured systems to the active system and the other to the standby system, a switching signal such as a pulse is selectively input only to the system to be the active system. Perform That is, the switching signal is input to the first input terminal of only the system to be the active system. With this input, the switching signal is also input to the systems to be the standby system from the second input terminals of those systems.

According to the present invention, in the system to be the working system, the first pre-differentiating means and the two-state device in the switching control means use the switching signal such as a pulse to indicate that the system is the working system. In the system which should generate the active working system signal and become the standby system, the second pre-differentiating means and the two-state device in the switching control means use the switching signal to generate a regular standby signal indicating that the system is the standby system. Generate a system signal.

According to the present invention, the first pre-differentiating means converts a switching signal such as a pulse into a first synchronizing signal having a predetermined length, and the two-state device converts the first synchronizing signal into a current synchronizing signal. Convert to a signal. The second pre-differentiating means converts the switching signal into a second synchronization signal having a predetermined length, and the two-state device converts the second synchronization signal into a standby signal.

According to the present invention, in the first or second pre-differentiating means, the first signal delay means delays a switching signal such as a pulse and converts it into a first-order delayed signal, The delay means converts the first-order lag signal into a second-order lag signal by delaying the first-order lag signal, and the AND logic means performs the first or second-order lag signal during the period during which the first and second lag signals are simultaneously detected. And outputting a second synchronization signal.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a method for switching between an active system and a standby system according to the present invention;

FIG. 2 shows a redundant configuration system composed of a plurality of systems having an active / standby switching device according to the present invention. The systems 2 and 4 have a common configuration, and include active / standby switching devices 6 and 8, respectively. The switching pulse 10 of the system is input via the switch 12 to the input terminal 14 or
Selectively connected to 16. The input terminals 14 and 16 are connected to both the systems 2 and 4, that is, both the working system / standby system switching devices 6 and 8, respectively.

FIG. 1 shows the working system according to the present invention in FIG.
It is a block diagram which shows a standby system switching apparatus. The active / standby switching devices 6 and 8 each include two pre-differentiating circuits 18.
2 and 20 and a switching control circuit 21 including a JK flip-flop circuit 22 in common.
Will be described as a representative. Predifferentiation circuit 18 is input terminal 14
, And the pre-differentiation circuit 20 is connected to the input terminal 16.
Circuits 18 and 20 each have a clock pulse input terminal 23
Is also connected. The JK flip-flop circuit 22 is connected to the output terminals 24 and 26 of the pre-differentiating circuits 18 and 20, respectively, which are the J and K inputs of the circuit 22. Further, the circuit 22 is also connected to a clock pulse input terminal 23.

FIG. 3 shows the pre-differentiating circuit 18 and FIG.
20 is a circuit diagram showing a configuration common to 20. FIG. Hereinafter, the circuit 18 shown in FIG. 3 will be described as a representative. The pre-differentiating circuit 18 comprises two edge-triggered D flip-flop circuits 28 and 30
And an AND logic circuit 32 and an inversion logic circuit 34. Since the edge-triggered D flip-flop circuits 28 and 30 are connected in series, the upstream circuit 28 is connected to the input terminal 14 and outputs the output 36, and the downstream circuit 30 is connected to the input terminal 36.
And outputs the output 38. Both circuits 28 and 30 are also connected to clock pulse input terminal 23. FIG. 4 is a truth table of these edge-triggered D flip-flop circuits. As shown in FIG. 4, the edge-triggered D flip-flop circuits 28 and 30 used in this embodiment are synchronized with the rising edge of the clock pulse. To change the output. Inverting logic circuit 34 is connected to input terminal 38 and output terminal 40. The AND logic circuit 32 has an input terminal 36 and
40 and an output terminal 24.

In the above configuration, the active / standby system switching device operates as follows.

First, an operation method of the redundant configuration system shown in FIG. 2 will be described. When the system 2 is used as the working system, the input terminal 14 of the working system / standby system switching device 6 is selected by the switch 12, and
If the switching pulse 10 is given only to the terminal 14, a signal of the working system is output from the output terminal 42 by the function of the device 6 described later. That is, it is not necessary to directly apply the pulse 10 to the system 4. The switching pulse 10 to the input terminal 14 is also input to the active / standby switching device 8 as a pulse for instructing the transition to the standby system. In response to the function of the device 8, the signal of the standby system is output from the output terminal 44, and the system 4 transitions to the standby system. When the system 4 is changed to the working system again and the system 2 is changed to the standby system, the switch 12 may be switched to apply the switching pulse 10 only to the input terminal 16.

Next, the operation common to the active / standby switching devices 6 and 8 in FIG. 2 will be described with reference to FIG. 1, FIG. 5 showing a truth table of the JK flip-flop circuit 22 shown in FIG. This will be described with reference to a time chart shown in FIG.

In this embodiment, an operation in the case where the system 2 having the active / standby system switching device 6 in FIG. 1 is set as the active system in accordance with the above-described operation method of the redundant configuration system will be described. At the time of reset (time T1 in FIG. 6), the respective inputs 14 and 16 of the pre-differentiation circuits 18 and 20 and the output 42 of the JK flip-flop circuit 22 are both set to Low. At any time T2 at the input 14 of the pre-differentiation circuit 18, 1
When the switching pulse 10 which keeps the High level during the period τ0 equal to or longer than the clock is input, the pulse 52 (one of the high state) in the period ) Is output from output 24.
On the other hand, no pulse is input to the input 16 of the pre-differentiation circuit 20, as described in the above-described redundant configuration system operation method. The low state is maintained even during the time T5. When these outputs 24 and 26 are input to the JK flip-flop circuit 22 as the J input 24 and the K input 26, respectively, they are synchronized with the falling edge 54 of the clock pulse at time T4 as shown in the truth table of FIG. Thus, the output 42 of the JK flip-flop 22 rises from Low to High, and enters the steady state 56. That is, the system 2 including the active / standby switching device 6 of FIG. 1 is set as the active system.

Next, the operation when the system 2 having the active / standby system switching device 6 shown in FIG. 1 transitions from the active system to the standby system will be described. In this case, in order to transition the system 4 to the active system, the switching pulse 10 sent to the system 4 and kept at the high level for a period τ4 of one or more clocks is input to the input terminal 16 of the pre-differentiation circuit 20. Input at an arbitrary time T6. Then, the pre-differentiation circuit 20, which will be described later, generates a one-clock-length synchronization pulse in a period τ6 between time T7 and time T9.
60 is output from the output 26 and the JK flip-flop circuit 22
K Input as input 26. On the other hand, since the output 24 in the Low state is input to the J input 24 of the JK flip-flop circuit 22, the JK flip-flop is synchronized with the falling edge 62 of the clock pulse at time T8 according to the truth table of FIG. The output 42 of the circuit 22 falls from High to Low, and enters a steady state 64. That is, the system 2 including the active / standby system switching device 6 in FIG. 1 transitions from the active system to the standby system.

Thereafter, when the system 2 having the active / standby system switching device 6 of FIG. 1 again transitions from the standby system to the active system,
In the same way as when the system 2 is initially set to the working system, the switching pulse 10 for maintaining the High level for one or more clocks may be given to the input terminal 14 of the pre-differentiating circuit 18, which means that the switch 12 in FIG. Means that only the terminal 14 needs to be selectively connected.

Finally, FIG. 3 shows a common operation of the pre-differentiating circuits 18 and 20 of FIG. 1, FIG. 4 shows a truth table of the edge-triggered D flip-flop circuit, and FIG. This will be described with reference to a chart. Since the operations of the circuits 18 and 20 are common, the circuit 18 will be described as a representative. At reset, both input 14 and output 24 are low (time T1). At an arbitrary time (time T2), when the switching pulse 10 which maintains the high level in the period τ0 of one clock or more is input to the input 14, the rising edge 66 of the clock pulse (time T3 ), The output terminal 36 of the edge trigger type D flip-flop circuit 28 also rises 68 and goes high. This rising 68 is ANDed with the edge trigger type D flip-flop circuit 30.
It becomes an input 36 common to the logic circuit 32. The rising edge 68 at the input 36 is further delayed by one clock delay period τ2 by the edge trigger type D flip-flop 30 (time T
5) A rising edge appears at the output terminal 38, and the rising edge is inverted by the inversion logic circuit 34.
Is input Low to the input 40 of the AND logic circuit 32. As a result, during one clock period τ2 from time T3 to time T5, both inputs 36 and 40 of the AND logic circuit 32 are applied.
Since High is input, a synchronization pulse 52 of one clock length is also output at the output 24. Thus, the pre-differential circuit 18
And 20 output a synchronization pulse 52 having a length of one clock in response to the input of the switching pulse 10,
The operation as described above for the active / standby switching device of FIG. 1 for maintaining the low state is realized.

In this embodiment, the edge-triggered D flip-flops 28 and 30 output delayed pulses in synchronization with the rise of the clock pulse, and the JK flip-flop 22 operates in a steady state in synchronization with the fall of the clock pulse. However, it is of course possible to adopt a configuration in which the rising and falling edges of the clock pulse used as the output timing of these flip-flops are opposite to each other.

In the above embodiment, the switching pulse input to the active / standby switching device is a pulse that keeps the High level for a period of one or more clocks, and is output from the active / standby switching device. As for the stationary signal, the high level signal indicates switching to the active system, and the low level signal indicates switching to the standby system. The present invention is not limited to the above-described embodiment.
The display of w may be reversed.

Further, in the embodiment shown in FIG. 2, a double redundant configuration system including two devices is shown. However, the present invention further increases the redundancy and provides n standby systems for one active system. Can be applied to the (n + 1) common configuration including

[0026]

As described above, according to the present invention, when a system is changed to the active system and the system which was the active system is changed to the standby system, only the system to be made the active system is selectively used. What is necessary is just to give a switching signal, and switching can be performed in a short time. This means that the conventional redundant configuration system shown in FIG. 8 must access the registers 80 and 82 of both systems 2 and 4, and furthermore, a signal instructing a transition to the active system and a transition to the standby system. This is apparent from the fact that it has been time-consuming to provide the signal instructing the command. In addition, according to the present invention, since the register means such as the registers 80 and 82 shown in FIG.
It is also possible to solve the problem that the standby system cannot be switched, and to reliably switch between the active system and the standby system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an active / standby switching device according to the present invention.

FIG. 2 is a functional block diagram illustrating a redundant configuration system including a plurality of systems including the active / standby switching device of FIG. 1;

FIG. 3 is a circuit diagram showing a configuration common to the pre-differentiating circuit in the embodiment shown in FIG. 1;

FIG. 4 is a diagram showing a truth table of the edge trigger type D flip-flop circuit.

FIG. 5 is a diagram showing a truth table of the JK flip-flop circuit.

FIG. 6 is a time chart showing the operation of the active / standby switching device of FIG. 1;

FIG. 7 is a time chart illustrating an operation of the pre-differential circuit of FIG. 2;

FIG. 8 is a functional block diagram showing an example of a conventional redundant configuration system.

[Explanation of symbols]

 2,4 system 6,8 Active system / standby system switching device 18,20 Pre-differential circuit 21 Switching control circuit 22 JK flip-flop circuit 28,30 D flip-flop circuit 32 AND logic circuit

Claims (7)

[Claims] 1. A method for switching one of a plurality of redundantly configured systems to an active system or a standby system in a method for switching between an active system and a standby system, comprising the steps of: Selectively inputting a switching signal to the plurality of systems;
And a step of inputting the switching signal to a system to be a standby system. 2. The method according to claim 1, further comprising: receiving the switching signal in a system to be the working system to generate a stationary working system signal indicating that the system is a working system. An active system signal generating step of receiving the switching signal in the system to be the standby system, and generating a standby system signal indicating that the system is the standby system. Characteristic switching method between active system and standby system. 3. The method according to claim 2, wherein the step of generating the working signal includes a first pre-differentiating step of converting the switching signal into a first synchronization signal having a predetermined length. A first conversion step of converting the synchronization signal into the working signal, and the protection signal generation step includes a second pre-differentiation for converting the switching signal into a second synchronization signal having a predetermined length. And a second conversion step of converting the second synchronization signal into the standby signal. 4. The method of claim 3, wherein each of the first and second pre-differentiating steps comprises: respectively, delaying the switching signal and converting it into a first-order delayed signal; Delaying the second-order lag signal to convert it to a second-order lag signal; and during the period in which the first-order lag signal and the second-order lag signal are simultaneously detected, the first or second synchronization signal is converted. And a method of switching between the active system and the standby system. 5. An active / standby system switching device which is provided in each of a plurality of redundantly configured systems and selectively switches a system to which the self belongs among the plurality of systems to an active system or a standby system. A first input terminal to which a switching signal indicating an instruction to switch any of the plurality of systems to an active system is input; and a first input terminal of the device in a system other than the system to which the plurality of systems belong. A second input terminal connected to the first terminal, and a first input terminal receiving the switching signal, a second input signal for setting a system to which the self belongs to a current system;
Receiving the switching signal at an input terminal of the current system and the standby system, the switching control means for providing a standby system signal for setting the system to which the own device belongs to the standby system to the system to which the own device belongs. System switching device. 6. The apparatus according to claim 5, wherein the switching control means is connected to the first input terminal, and converts the switching signal into a first synchronization signal having a predetermined length. Pre-differentiating means, second pre-differentiating means connected to the second input terminal for converting the switching signal into a second synchronizing signal having a predetermined length, and first and second pre-differentiating means And a two-state device for converting the first or second synchronization signal into the working system signal or the protection system signal. 7. The apparatus according to claim 6, wherein said first and second pre-differentiating means are respectively connected to said first or second input terminal, and delay said switching signal to produce a first-order signal. First signal delay means for converting the signal into a delay signal; second signal delay means connected to the first signal delay means for delaying the first-order signal and converting it to a second-order signal; The first signal delay means is connected to an output terminal of the first signal delay means and an output terminal of the second signal delay means, and the first delay signal and the second delay signal are simultaneously detected. Or an active / standby system switching device including AND logic means for outputting a second synchronization signal.