JP3123743B2 - Monitoring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring device for monitoring the operation of a backup circuit provided in a backup device used when a normally used working device stops operating normally.

[Conventional technology]

The backup circuit is provided so as to be switched when a normally used circuit (working side) stops operating normally in a device requiring high reliability such as a communication device. It is the monitoring device that constantly monitors the standby circuit so that the standby circuit functions normally when switching is performed.

A monitoring signal such as a dummy signal is generated and given to a monitored circuit (stand-by circuit) to a conventional monitoring apparatus, and it is determined whether or not the circuit operation of the monitored circuit is normal based on an output signal from the monitored circuit. Is generally performed by a monitoring signal determination circuit.

Conventionally, this type of monitoring apparatus has a configuration as shown in FIG. 4, in which a monitoring signal determination circuit 413 detects an error and has a periodicity output from the monitoring signal generation circuit 411. The pattern code sequence is compared with the pattern code sequence returned from the spare circuit 400, and a judgment is made by the monitor signal judgment circuit 413 as to whether they match or not, and the judgment result signal 416 is output. Was.

[Problems to be solved by the invention]

In the above-described conventional monitoring device, the pattern code sequence generated by the monitor signal generation circuit is sent to the spare circuit, and the pattern code sequence conveyed through the spare circuit is compared with the transmitted pattern code sequence to determine whether they match. The monitoring signal determination circuit detects whether the monitoring signal determination circuit matches or does not match. Therefore, if a failure occurs in the monitoring signal determination circuit itself, any pattern code string returned from the backup circuit is detected. There is a drawback that there is no means.

[Means for solving the problem]

The monitoring device of the present invention is a monitoring device for monitoring the operation of a backup circuit of a backup device used when a normally used working device stops operating normally, and generates a monitoring signal to be sent to the backup circuit. A monitoring signal generation circuit, a prohibition circuit for prohibiting transmission of the monitoring signal to the standby circuit at a predetermined timing, a monitoring signal receiving circuit for receiving the monitoring signal from the standby circuit, and a monitoring signal An activity detection circuit for detecting an activity of the backup circuit based on the determination of the transmission signal output from the reception circuit and the timing;

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG. 2 is a diagram showing an example of waveforms of main signals in the first embodiment shown in FIG.

In FIG. 1, the monitoring device 110 of the first embodiment includes a monitoring signal generating circuit 111 for generating a pattern code string a having periodicity, and an output b of the pattern code string to the backup circuit 100, which is internally predetermined. Circuit 112
And a monitoring signal receiving circuit 113 for receiving the output signal c from the standby circuit 100, and comparing the output signal from the monitoring signal receiving circuit 113 with the active output signal from the prohibition circuit 112 to compare the standby signal with the active signal. And an activity detection circuit 114 for judging the normality of the operation.

Next, the operation of this embodiment will be described with reference to FIG.

The pattern code string a having periodicity generated by the monitor signal generation circuit 111
Is input as a signal b. The output signal c from the backup circuit 100 is received by the monitoring signal receiving circuit 113.

The prohibition circuit 112 has a function of prohibiting the pattern code string a output by the monitoring signal generation circuit 111 at its own timing. Since the monitoring signal receiving circuit 113 during this prohibited period does not receive the signal c from the spare circuit 100, Naturally, it is recognized as a detection abnormality. By repeating this, if the spare circuit 100 is normal, the output of the monitor signal receiving circuit 113 has an activity. This activity is detected by the activity detection circuit 114 to determine whether the spare circuit 100 is good or not.
Here, if there is a failure in the monitoring device 110, the monitoring device 110 has no activity that changes at the timing that occurs in the prohibition circuit 112, and the monitoring device 110 can be confirmed by distinguishing the activity.

Next, a description will be given with reference to FIG. a is an output signal of the monitor signal generation circuit 111, t is a timing of prohibition of the prohibition circuit 112 (prohibited by “H”), b is a pattern code string after passing through the prohibition circuit 112 (input signal of the spare circuit 100), c is the spare circuit 1
00 is an output signal, and d is the output signal c.
A judgment result signal indicating the result of the judgment (“H” is good and “L” is bad) is input to 113 and the pass / fail of the spare circuit 100 is judged by the activity of the judgment result signal d.

If the failure of the spare circuit 100 or the failure of the monitoring device 110 occurs, the judgment result signal d becomes "L" as shown in f of FIG.
Activity disappears in a row. Monitoring device 110
In the case of a fault whose output d is fixed at "H" as in the case of the signal g, the activity (change) eventually disappears, so that the fault can be recognized.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

In FIG. 3, the monitoring device 210 of the second embodiment inhibits the clock from the clock source 215 by the clock source 215 for generating the clock and the frequency division of the clock from the clock source 215 by n (an integer of n2). A prohibition circuit 212, a monitor signal generation circuit 211 for generating a pattern code string h in a portion that does not change in some places by the clock divided by n from the prohibition circuit 212, and sending it to the preparatory circuit 200;
A monitoring signal receiving circuit 213 for receiving the signal i from the signal generator 200; and an activity detecting circuit 214 having a monomultivibrator circuit having a time constant substantially equal to the timing of frequency division by n in the inhibiting circuit 212. Make up.

 Next, the operation of the second embodiment will be described.

First, the clock source 215 supplies a clock to the inhibition circuit 212. The prohibition circuit 212 divides the input clock by n, prohibits its own clock by the output of this n-frequency division, and sends it to the monitor signal generation circuit 211. The output of the monitor signal generation circuit 211 is a pattern code string h having a portion that does not change in some places. If the spare circuit 200 is normal, a pattern code string i having a portion that does not change in some places is input to the monitor signal receiving circuit 213, and as a result, as shown in FIG.
Output a pulse waveform j similar to the determination result signal d.

Since the prohibition timing (cycle in this case) by frequency division in the prohibition circuit 212 is known in advance, the time constant of the mono-multivibrator circuit in the activity detection circuit 214 should be set to be larger than the prohibition timing. As a result, the detection of the activity according to the purpose is easily realized.

〔The invention's effect〕

As described above, the present invention has a monitoring signal generation circuit, a prohibition circuit at the output of the monitoring signal generation circuit, and output signal active means for intentionally constantly changing the output of the pass / fail judgment result. Since the output of the pass / fail judgment result has an activity (changes) when both of the devices are normal, the pass / fail judgment means is provided to judge the pass / fail, so that not only the standby circuit but also the monitoring device itself can be improved. There is an effect that the normality can be confirmed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing an example of a waveform of a main signal in the first embodiment shown in FIG. 1, FIG. 3 is a block diagram showing a second embodiment of the present invention, and FIG. It is a block diagram showing an example. 100,200,400 …… Spare circuit, 110,210,410 …… Monitoring device,
111, 211, 411 monitoring signal generating circuit, 113, 213 monitoring signal receiving circuit, 413 monitoring signal determining circuit, 112, 212 inhibiting circuit, 114, 214 activity detecting circuit, 115
Prohibition timing information signal, 215 ... clock source, 116, 21
6,416 ... Result signal.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Makino 2 Miyagi-cho, Yamato-cho, Kurokawa-gun, Miyagi Prefecture Miyagi NEC Co., Ltd. (56) References 63-26042 (JP, A)

Claims (1)

(57) [Claims] A monitoring device for monitoring the operation of a spare circuit of a spare device used when a normally used working device does not operate normally. A monitoring device for generating a monitor signal to be sent to the spare circuit. A signal generation circuit, a prohibition circuit for prohibiting transmission of the monitor signal to the spare circuit at a predetermined timing, a monitor signal receiving circuit for receiving the monitor signal from the spare circuit, and a monitor signal receiving circuit A monitoring circuit comprising: an activity detection circuit configured to detect an activity of a spare circuit based on a determination of the transmission signal output from the backup signal and the timing.