JPH01295399A - Alarm monitor device - Google Patents

Abstract

PURPOSE:To prevent the contact fault and at the same time to reduce the power consumption by cutting down the current flowing to an external alarm contact after this contact is closed. CONSTITUTION:While an external alarm contact 1 is kept open, no current flows to a 1st photocoupler 20 and a current flows into a photocoupler 30 from a logic power supply 24 via a resistance 31. Thus a phototransistor 30B contained in the photocoupler 30 is turned on. Then the current flows via an external interface power supply 23, a resistance 21, the photocoupler 20, the contact 1 and the photocoupler 30 at an instant when an external contact signal is closed. Then an inverter 40 is inverted and the phototransistor 30B of the photocoupler 30 is turned off. Thus the current flowing through the contact 1 is cut down via a resistance 32. In such a way, the power consumption is reduced with no occurrence of the contact fault.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an alarm monitoring device, and more particularly to an alarm monitoring device that reduces power consumption of a power source necessary for operating the device.

[Conventional technology]

In general, alarm monitoring devices employ a method of constantly supplying a constant level of current in order to ensure reliable operation of the device in an emergency.

On the other hand, when energizing such a device, a method is adopted in which the current value flowing through the external alarm contact is always set to a low value from the standpoint of energy conservation.

[Problem to be solved by the invention]

However, in the above conventional example, as mentioned above,
Since the current flowing through the external alarm contacts is always at a low value, some external alarm contacts deviate from the minimum switching load condition and cause contact failure, causing the inconvenience that alarm operations are not performed normally.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an alarm monitoring device which can improve the disadvantages of the conventional example and can effectively save power without causing contact failure.

[Means to solve the problem]

In the present invention, in an alarm monitoring device that includes an external alarm contact and a contact monitoring circuit unit that monitors the ON or OFF state of the external alarm contact, the current flowing through the external alarm contact after the external alarm contact closes is reduced. A configuration is adopted in which a energizing current reduction circuit section for controlling the contact point monitoring circuit section is provided side by side with the contact monitoring circuit section. This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

The embodiment shown in FIG. 1 includes an external alarm contact 1 and a contact monitoring circuit section 2 that monitors whether the external alarm contact 1 is on or off. The contact monitoring circuit section 2 is provided with an energizing current reduction circuit section 3 that reduces the current flowing through the external alarm contact 1 after the external alarm contact 1 is closed.

The contact monitoring circuit section 2 includes a first photocoupler 20 and a resistor 2.
1.22 and the first photocoupler 2
0 is the light emitting diode section 20A and the phototransistor 2
0B.

Of these, the diode section 20A has its anode A1 side connected to the positive potential side of an interface power supply 23 connected to the outside via a resistor 21, and its cathode side connected to one terminal IA of the external alarm contact 1. It is connected.

Further, the phototransistor section 20B is incorporated in a grounded emitter configuration, and its collector C6 side is connected to the positive potential side of the logic power supply 24 via the resistor 23.

The collector terminal CI of this phototransistor section 20B is
Operation information of the external alarm contact 1 is output to the data processing section 100.

On the other hand, the energizing current reduction circuit section 3 is configured with the second photocoupler 30 as a main part. The light emitting diode section 30A of this second photocoupler 30 has an anode A
The second side is connected via the resistor 31 to the positive potential side of the logic power supply 24 described above. Further, the cathode 2 side of this light emitting diode section 30 is connected to the output end of an inverter 40 . This inverter 40 has its input terminal connected to the collector C1 side of the phototransistor 20B in the first photocoupler 20, and thereby inverts the operation information of the external alarm contact 1 and outputs it to the cathode Kt. It can be applied.

Further, the phototransistor portion 30B of the second photocoupler 30 is incorporated into the circuit with its emitter grounded, and its collector terminal C2 is connected to the other terminal IB of the external alarm contact l described above. A resistor 32 is connected in parallel to this phototransistor section 30B.

Next, the overall operation of the above embodiment will be explained.

When external alarm contact 1 is open, first photocoupler 2
No current flows through 0. Therefore, the input of the inverter 40 becomes a high level "H" and the output becomes a low level "L". Also, current flows into the photocoupler 30 from the logic power supply 24 via the resistor 31, and the photocoupler 30 The phototransistor 30B inside is turned on.

Next, at the moment when the external contact signal is closed, the external interface power supply 23. Resistance 21. First photocoupler 20. Current flows through the external alarm contact 1 and the second photocoupler 30 in sequence.

After the current flows as described above, the inverter 40
is reversed, the phototransistor 30B in the second photocoupler 30 is turned off, and the current flowing through the external alarm contact 1 passes through the resistor 32 instead of the second photocoupler 30, and is significantly reduced.

Since the resistors 21 and 32 are selected within a range that satisfies the operating conditions of the first photocoupler 20, the phototransistor 20B in this first photocoupler 20 is connected to the external alarm contact 1.
will remain on until it is released. Note that the on or off state of the phototransistor 20B in the first photocoupler 20 is pulled up by the resistor 22 and is reliably input to the data processing section 9 at the subsequent stage.

〔Effect of the invention〕

As described above, according to the present invention, since the current flowing through the external alarm contact is reduced after it closes, it is possible to almost completely eliminate the situation where this contact causes a contact failure. At the same time, it is possible to provide an unprecedented and excellent alarm monitoring device that can effectively save power.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. 1... External alarm contact, 2... Contact monitoring circuit section, 3... Current reduction circuit section. Patent applicant Japan Electric Co., Ltd. Agent Patent attorney Isamu Takahashi Figure 1 (aVVkyu 1 to Y Yoshi) 9μノ

Claims (1)

[Claims] (1) In an alarm monitoring device equipped with an external alarm contact and a contact monitoring circuit unit that monitors the ON or OFF state of the external alarm contact, the current flowing through the external alarm contact after the external alarm contact is closed is An alarm monitoring device characterized in that a energization current reduction circuit section for reducing the energization current is attached to the contact monitoring circuit section.