JPH02163900A - Electronic alarm logic circuit - Google Patents

Abstract

PURPOSE:To eliminate malfunction, to reduce cost, and to improve reliability by providing a third switch to output an alarm when the second switch is under an ON state and stop outputting the alarm when a second switch is under an OFF state. CONSTITUTION:The alarm is outputted from the third switch 500 only when a first alarm signal is inputted, and the second alarm signal is not inputted. And in this case, the time from a point where the first alarm signal is inputted to another point where the second switch 400 is turned on is delayed for a time constant to be determined by the product of a capacitor C and a resistance R. Thus, the malfunction never occurs, and the electronic alarm logic circuit having the low cost and high reliability can be obtained by using, for example, an electric switch, as the third switch 500 without using a relay.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a low-cost and highly reliable electronic alarm logic circuit that is used in an alarm test section of a transmission device and outputs an alarm by determining the logic of two or more alarm inputs. The purpose of the present invention is to provide an electronic alarm logic circuit, which has input terminals for inputting first and second alarm signals, and outputs an alarm only when the first alarm signal is input. 1, a second electrode and a third electrode;
and a second electrode connected to the first and second alarm signal input terminals, respectively, and a first switch that turns on between the first and third electrodes when the second alarm signal is input; a capacitor connected between the first and third electrodes of the switch and having a predetermined capacitance value, and first, second and third electrodes, the first and second electrodes each having a first a second switch that is connected to the first and third electrodes of the switch, and is turned on between the first and third electrodes when the first alarm signal is input, and is turned off when the second alarm signal is input; a resistor connected between a power source outputting a predetermined voltage and a second electrode of the second switch and having a predetermined resistance value; and a resistor connected between a third electrode of the second switch and the power source. , and a third switch which outputs an alarm when the second switch is on and does not output an alarm when it is off.

[Industrial application field]

The present invention is used in an alarm test section of a transmission device, etc.
The present invention relates to an improvement in an alarm logic circuit that determines the logic of two or more alarm inputs and outputs an alarm.

At this time, there is a need for a low-cost, high-reliability alarm logic circuit.

[Conventional technology]

FIG. 4 is a block diagram showing the configuration of a conventional circuit.

When detecting and processing alarms from each circuit in the alarm test section of a transmission device, etc., a circuit that outputs the output obtained from the logical formula AX100 for one alarm (A) and another alarm (B) as an alarm. is sometimes used. That is,
In order to switch to a backup circuit (which issues alarm B when a failure occurs in that circuit) when a certain circuit generates a fault and issues an alarm A, the TI indicates that the backup circuit is operable.
I! It is necessary to acknowledge the For this reason, a circuit is used that outputs the output obtained from the AXB logical formula as an alarm.

In FIG. 4, it is assumed that in a certain device, for example, a signal indicating alarm A is input to contact 1 of a relay, and contact 1 of the relay is turned on. Then, current flows from the -48V power supply through the relay drive circuit 3 to the contact 1 of the relay, turning on the contact 5 of the corresponding relay. On the other hand, when the alarm B that should be input to the relay contact 2 does not occur, no current flows through the relay drive circuit 4, the corresponding relay contact 6 remains on, and the alarm A is generated in the alarm processing section 7. Detects and outputs an alarm.

Also, when signals indicating alarm A and alarm B are input to contacts 1 and 2 of the relay, respectively, current flows from the voltage (-48V) through the relay drive circuit 3.4, and the contact 5 of the corresponding relay. Turn on and turn 6 off. As a result, the alarm processing section 7 does not output an alarm.

Further, when the alarm A is not generated and a signal indicating the alarm B is input to the contact 2 of the relay, current flows through the relay drive circuit 4 and turns off the contact 6 of the corresponding relay. In this case as well, the alarm processing section 7 does not output an alarm.

In this way, only when alarm A is input to contact 1 of the relay and alarm B is not generated, the alarm processing section 7 outputs an alarm. Then, in a switching circuit (not shown), alarm A
Switch from the circuit that issued the alarm B to the circuit that issued the alarm B.

[Problem to be solved by the invention]

However, the above-mentioned circuit has the problem of low reliability because the cost of the relay is high and the life of the contacts of the relay is short.

Also, if the timings of alarm A and alarm B are slightly different due to close timing, that is, if alarm B is input after a while after alarm A is input, the alarm processing unit will output an alarm only for alarm A. Since the circuit that issued the alarm B also has a fault, the circuit cannot be used even if the circuit is switched, resulting in a malfunction.

Therefore, an object of the present invention is to provide a low-cost and highly reliable alarm logic circuit.

[Means to solve the problem] The above problem is solved by the circuit shown in FIG.

That is, in FIG. 1, 300 is an alarm logic circuit which has input terminals for inputting first and second alarm signals and outputs an alarm only when the first alarm signal is input. has a third electrode, the first and second electrodes are connected to the first and second alarm signal input terminals, respectively, and when the second alarm signal is input, the connection between the first and third electrodes is turned on. This is the first switch.

C is a capacitor connected between the first and third electrodes of the first switch and having a predetermined capacitance value.

400 has first, second and third electrodes, the first and second electrodes are respectively connected to the first and third electrodes of the first switch, and when the first alarm signal is input; A second switch is turned on between the first and third electrodes and turned off when the second alarm signal is input.

R is a power supply that outputs a predetermined voltage and a second switch of a second switch.
It is a resistor connected between the electrodes of , and having a predetermined resistance value.

A third switch 500 is connected between the third electrode of the second switch and the power source, and outputs an alarm when the second switch is on, and does not output an alarm when the second switch is off.

[For production]

In FIG. 1, the first alarm signal is transmitted to the second switch 40.
When input to the first electrode of 0, the connection between the first and third electrodes of the second switch 400 is turned on. By applying the output of the third electrode of the second switch 400 to the third switch 500, the third switch 500 outputs an alarm.

Further, when the second alarm signal is input to the second electrode of the first switch 300, the connection between the first and third electrodes of the first switch is turned on, and the second switch 400 is turned off. At this time, the third switch 500 does not output an alarm.

As a result, the electronic alarm logic circuit outputs an alarm from the third switch 500 only when the first alarm signal is input and the second alarm signal is not input.

In the above case, after inputting the first alarm signal, the second alarm signal is input.
The time it takes for switch 400 to turn on is delayed by a time constant determined by the product of capacitor C and resistor R. Therefore, no malfunction occurs. Furthermore, by using, for example, an electronic switch as the third switch 500 without using a relay, it is possible to create a highly reliable electronic alarm logic circuit at low cost.

〔Example〕

FIG. 2 is a circuit diagram of an embodiment of the present invention.

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

The same reference numerals indicate the same objects throughout the figures.

In FIG. 2, the signal indicating alarm A is at contact 10 of the relay.
, the relay contact 10 turns on. Then, the seventh transistor (hereinafter referred to as Tr) 40 whose potential at point a is grounded is turned on, the photocoupler 50 is operated through the resistor R4, the diode PD of the photocoupler 50 is turned on, and the alarm output is set to the ground potential (“0”). ). The time delay from the input of the signal indicating alarm A described above to the turning on of Tr40 is determined by the capacitor CI (for example, 22
μF) and the value of the resistance R, (for example, 100 KΩ),
The power supply voltage (Vcc) and the base where Tr40 is turned on.
Time constant C5 determined by the ratio of the voltage between the emitter and the lid (■, )
- It can be determined by the value of R3■□/Vcc. (
On the other hand, when a signal indicating alarm B is input to the contact point 20 of the relay, the potential at point b becomes ground, so the Tr 30 is turned on. Therefore, the Tr40 is turned off and the photocoupler 50 is also turned off, so that the alarm output is stopped. (For example, it becomes "1'.") In this way, the logical processing of alarm A x alarm 100 is performed.

In addition, multiple alarms (A+ to A,
), (Bl to Bfi), the above-described circuit can be applied. That is, in FIG. 3, alarm A,
Relay contact 1.0 corresponding to ~Afi, B, ~B, .
The outputs of -1 to 10-n and 20-1 to 20-n are combined and added to points a and b.

As a result, if there is an input of an alarm signal for even one of the alarms A, . on the other hand,
If there is an alarm signal input for any one of alarms 81 to B,
The potential at point b becomes ground and Tr30 is turned on. Therefore, Tr40 is turned off and the photocoupler 50 does not output an alarm.

FIG. 3 is a circuit diagram of a second embodiment of the present invention, and FIG. 4 is a block diagram showing the configuration of a conventional circuit.

In the figure 300 is the first switch, 400 is the second switch, 500 is the third switch, C is a capacitor, R is resistance shows.

〔Effect of the invention〕

As described above, according to the present invention, a low-cost and highly reliable electronic alarm logic circuit can be realized with a simple circuit configuration.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a circuit diagram of an embodiment of the present invention. 4 Aosei ΣHosubu o-z2D non-4
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Claims (1)

[Scope of Claims] An alarm logic circuit having input terminals for inputting first and second alarm signals, and outputting an alarm only when the first alarm signal is input, comprising: 3 electrodes, the first and second electrodes are connected to the first and second alarm signal input terminals, respectively, and when the second alarm signal is input, the first and third electrodes are connected to the first and second alarm signal input terminals. a first switch (300) that is turned on; and a first switch (300) connected between the first and third electrodes of the first switch;
A capacitor (C) having a predetermined capacitance value, and first, second and third electrodes, the first and second electrodes being respectively connected to the first and third electrodes of the first switch. a second switch (400) that is connected and turns on between the first and third electrodes when the first alarm signal is input, and turns off when the second alarm signal is input; a resistor (R) connected between a power source that outputs a voltage and a second electrode of the second switch and having a predetermined resistance value;
and a third switch (500) connected between the third electrode of the second switch and the power source, which outputs an alarm when the second switch is on and does not output an alarm when the second switch is off. An electronic alarm logic circuit is provided.