JPH04103000A - Alarm detecting circuit - Google Patents

Abstract

PURPOSE:To reduce the load of an alarm processing circuit by providing this alarm detecting circuit with N resistors connecting their one terminals to input terminals for receiving alarm signals, collectively connecting the other terminals as compound connection and having the same resistance value and specific 1st and 2nd resistors, and a comparator. CONSTITUTION:This alarm detecting circuit is provided with N resistors 41 to 4n connecting their one terminals to the input terminals 31 to 3n for receiving alarm signals and collectively connecting the other terminals as compound connection, a resistor 50 connecting one terminal to the compound connection side of the N resistors 41 to 4N and connecting the other terminal to a power supply Vcc, resistors 61, 62 for setting up reference potential lower than the 1/2 Vcc and higher than 1/3 Vcc, and a comparator 70 for comparing the reference potential with potential voltage impressed on the compound connection side of the resistors 41 to 4n. Respective resistors 41 to 4n, 50 have the same resistance value. Only when two or more alarm signals out of alarms from an alarm generating source 1 are received, the generation of an alarm is recognized. Consequently, the logical operation processing of the alarm processing circuit 2a is made unnecessary and the load of the circuit 2a can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an alarm detection circuit, and particularly to an alarm detection circuit that detects when any two or more alarms occur among N alarms transmitted from an alarm source. This invention relates to an alarm detection circuit that recognizes.

[Conventional technology]

In alarm detection, there are rare cases where it is desired to recognize as an alarm only when two or more alarms are generated from the alarm source. For example, when three or four power supplies are operated in parallel, even if one power supply fails, will it not affect the entire system because it is running in parallel?
This is the case when the power supply capacity becomes insufficient when the stand malfunctions, and an alarm must be issued as a serious failure.

Conventionally, in response to such alarm processing requirements, the third
As shown in the figure, N alarm signals emitted from the alarm source 1 are transferred as they are to the alarm processing circuit 2b using 0 information transmission lines, and are then transmitted within the alarm processing circuit 2. It was rather simple to use logical operations to determine whether 122 or more alarms had occurred.

[Invention or problem to be solved]

In conventional alarm detection systems, the alarm processing circuit is a complex circuit that can perform advanced logical operations, or an intelligent one with a built-in microcomputer.
In addition to the disadvantage that the burden on the alarm processing circuit is large, the number of wiring increases without increasing the number of sources, which causes problems within the device. There was a problem that the wiring was complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an alarm detection circuit that can reduce the burden on the alarm processing circuit and reduce the number of wires to the alarm processing circuit by only one.

[Means to solve the problem]

The alarm detection circuit of the present invention includes N resistors having the same resistance value, one of which is connected to an input terminal for receiving an alarm signal and the other of which is double-connected, and the N resistors are double-connected to one side. a first resistor connected to one side and the other to a power source and having the same resistance value as the resistor; and a reference potential set to be lower than one-third and higher than one-third of the power source. This configuration includes a second resistor, and a comparator that performs a voltage comparison between the reference potential and the potential of the N-side inner resistor that is double-connected.

〔Example〕

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

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
It is a figure which shows the voltage waveform of the A, B point and the output terminal 80 in a figure. In FIG. 1, the g-alarm detection circuit is provided between the alarm generation source 1 and the temporary alarm processing circuit 2a.
has N generation sources, and when an alarm is issued, it is assumed that earth air is output. The alarm detection circuit includes N resistors 41 to 4n, one of which is connected to the input terminals 31 to 3n that receive the alarm signal, and the other of which is connected in multiple ways. Connect one side to the power supply V and the other side. 0, resistors 61 and 62 for setting a reference potential that is lower than one-third and higher than one-third of the power supply Vco, and this reference potential and resistor 41. .about.4n and a comparator 70 that performs a voltage comparison with the potential of the dual-connected side. Here, resistors 41~
4n and 50 have the same resistance value.

The operation will be explained below. When one earth alarm signal from the alarm source 1 is input to any of the input terminals 31 to 3n, which one of the resistors 41 to 4n connected to the input terminal is Power supply V. A voltage of -3/0 is generated at point B. Further, when two alarms are generated, a voltage of -3/3 of the power supply Vcc is generated at point B. If the number of alarm signals from alarm source 1 is 3 or more, the voltage at point B is the power supply V. It becomes even lower than one-third of C. Here, point B is connected to the negative input terminal of the comparator 70, point A is connected to the positive input terminal of the comparator 70, and point A is connected to the power supply V. It is set by resistors 8 and 62 to a potential lower than one-third of zero and higher than one-third of the power supply Vco. Therefore, when the number of alarm signal inputs from alarm source 1 is "0 and ]", comparator 7
When the output terminal 80 of 0 is at low level or the number of alarm signal inputs becomes "2 or more", the potential difference between point B and point A is reversed, and the output terminal 80 becomes high level as shown in Fig. 2. Become. In other words, a signal indicating that 12 or more alarm signals are input or present can be taken out from the output terminal 80. The alarm information obtained in this way is transmitted to the alarm processing circuit 2a via one line.
is input.

〔Effect of the invention〕

As explained below, the present invention is configured so that it is recognized as an alarm only when two or more alarm signals are received from the alarm source. No processing is required, the burden on the alarm processing circuit is reduced, and the number of wires connected to the alarm processing circuit can be reduced to one.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
A diagram showing voltage waveforms at points A and B and the output terminal in the diagram,
FIG. 3 is a diagram for explaining a conventional alarm detection circuit. ], ---One alarm source, 2a, 2b-circuit 31~
3n-1---input terminal, 450.6], 62--
・-Resistor, 70/80-・-Output terminal. Alarm processing 1-4 n.・−・Comparator,

Claims (1)

[Claims] One side is connected to the input terminal that receives the alarm signal, and the other side is connected in multiples and has N resistors having the same resistance value, and one side is connected to the side where the N resistors are connected in multiples, and the other is connected to the power source a first resistor connected and having the same resistance value as the resistor; a second resistor for setting a reference potential lower than one-half and higher than one-third of the power supply;
An alarm detection circuit comprising: a comparator that compares a voltage between the reference potential and a potential on a side of the N resistors that are double-connected.