JPH0271696A - Alarm output circuit - Google Patents

Abstract

PURPOSE:To simply and easily detect interruption of power supply in a device with low power consumption by driving a drive circuit for a relay activated by a power supply in a station housing at the primary side on the interruption of power via a diode connecting to a power supply of a device of the secondary side. CONSTITUTION:A logic signal turning off an alarm output is inputted to an alarm output control terminal 7, a cathode of a diode 6 for detecting power supply interruption in a device is connected to a power supply 8 in the device and a potential at a relay drive control voltage monitor point 11 is positive, a transistor(TR) 2 of a relay drive circuit is turned off, no current flows to a relay 1 activated by a power supply 9 in the station housing and no alarm is outputted. When an alarm output logic signal is inputted to the terminal 7, the TR 2 is turned on. On the other hand, if the power supply 8 is interrupted, the potential of the terminal 7 and the power supply 8 is made indefinite and a current flows from the power supply 9 to ground 10 via a diode 5 and the potential of the monitor point 11 is negative and the relay 1 is operated by the power supply 9. Thus, the interruption of the power supply in the device is detected with low power consumption while no current flows to the relay simply and easily without using any exclusive circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an alarm output circuit for a communication device, and more particularly to an alarm output circuit for reporting a device failure due to a power failure on the secondary side within the device.

[Conventional technology]

Conventionally, this type of alarm output circuit uses a relay that is driven by the device's secondary power supply in order to output an alarm when the device's secondary power supply is cut off. This is an alarm output circuit in which current is passed through the relay, and when the secondary power supply in the device is cut off, the current flowing through the relay is cut off to output an alarm.

[Problem to be solved by the invention]

The above-mentioned conventional alarm output circuit due to a power outage in the device (secondary side) is normally in the IT state in which current flows through the relay from the device (secondary side) power source, which reduces the power consumption of the device. In addition, when using an alarm output due to a power outage in the device (secondary side) as a central building alarm output of the device, the alarm output due to a device failure other than a power outage in the device (secondary side) There was a problem in that the circuit had to be coupled with a conventional alarm output circuit in response to power cutoff within the device (secondary side).

[Means to solve the problem]

The alarm output circuit according to the present invention has been made in view of the above-mentioned conventional problems.The alarm output circuit has a function of detecting a power failure within the device (secondary side), and has a contact that closes when an alarm is output. A relay that operates from the power supply inside the station building (primary side), a relay multi-beam circuit that drives the above relay when a device failure occurs, and a relay drive circuit that drives the relay when the power inside the device (secondary side) is cut off. It has a diode arranged like this.

[Effect]

In the present invention, when the power inside the device (secondary side) is cut off, the relay drive circuit is turned on, the relay is driven, the relay contact is closed, and an alarm is output.

〔Example〕

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

The figure is a circuit diagram showing the configuration of an alarm output circuit according to an embodiment of the present invention. In the figure, the alarm output circuit includes a station alarm output control relay 1, a relay control transistor 2, a first resistor 3 for relay control, and a second resistor 3 for relay control.
, a first diode 5 for detecting power failure within the device (secondary side), and a second diode 6 for detecting power failure within the device (secondary side). In addition, 7 is an alarm output control terminal, 8 is a power supply voltage terminal inside the device (secondary side), 9 is a power supply voltage terminal inside the station building (primary side), 10 is a grounding terminal inside the device and inside the station building, 11 is a relay, This is a drive control voltage monitoring point. Further, 12 is a station alarm output circuit, 13 is a relay contact for outputting a station alarm, and 14 is a station alarm output terminal.

In addition, in the same figure, the emitter side of the relay control transistor 2 and the anode side of the first diode 5 for detecting power failure inside the device (secondary side) are connected to the ground inside the device and inside the station building. One side of the alarm output control relay 1 and one side of the second resistor 4 for relay control are connected to the power supply inside the station building (primary side), and a second diode 6 for detecting power failure inside the device (secondary side) The cathode side of is connected to the internal (secondary side) power supply of the device.

In such a configuration, a logic signal for turning off the alarm output is normally input to the alarm output control terminal 7, and
Since the cathode side of the second diode 6 for power failure detection (secondary side) is connected to the internal (secondary side) power supply, the potential of the relay drive control voltage monitoring point 11 is a positive potential, and the relay Since the control transistor 3 remains in the off state,
No current flows through the station alarm output control relay 1, and no station alarm is output. In addition, when outputting an alarm due to a device failure other than power failure within the device (secondary side), the relay drive control voltage is When the potential of the monitoring point 11 is not a negative potential, the relay control transistor 2 is turned on and current flows through the station alarm output control relay 1, and the station building 9 alarm output relay contact 13 is closed and the station Building alarm output circuit 12
outputs a station alarm from the station alarm output terminal 14. In addition, when outputting an alarm due to power failure inside the device (secondary side), the potential of the alarm output control terminal 7 and the power supply voltage terminal 8 inside the device (secondary side) may become unstable. , from the first diode 5 for power failure detection in the device (secondary side), through the first resistor 3° for relay control and the second resistor 4 for relay control to the second resistor 40 for relay control on one side. A current flows through the power supply voltage terminal 9 in the station building (primary side) connected to the station building, and the potential of the relay drive control voltage monitoring point 11 becomes a negative potential, so that the relay control transistor 2 is turned on and the above-mentioned The station building alarm is output in the same way as in the case of .

〔Effect of the invention〕

As explained above, the present invention includes a relay that has a contact that closes when an alarm is output and is driven by the in-house (primary side) power supply, a relay drive circuit that drives the relay when a device failure occurs, and an in-device ( By having a diode installed so that the relay is driven by the relay drive circuit when the power is cut off (secondary side), it is possible to easily detect a power cut in the device (secondary side) and save power consumption. In addition, it has the extremely excellent effect of being able to output an alarm in the event of a power outage within the device (secondary side) using the same circuit as the alarm output in the station building caused by a failure in other devices.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a circuit diagram showing an embodiment of an alarm output circuit according to the present invention. 1... Station alarm output control relay 2... Transistor for relay control, 3... Resistance of tube 1 for relay control, 4... Second resistor for relay control, 5... ...First diode for detecting power outage in the device (secondary side), 6. Work...Second diode for detecting power outage in the device (secondary side),
7...Alarm output control terminal, 8...Inside the device (secondary side) power supply voltage terminal, 9...Inside the station building (primary side) power supply voltage terminal, 10...Inside the device and Station building grounding terminal, 11
Fist: Relay drive control voltage monitoring point, 12: Station building death alarm output terminal, 13: Station building alarm output relay contact, 14: Station building death alarm output terminal. Patent applicant: NEC Corporation

Claims (1)

[Claims] A relay that has a contact that closes when an alarm is output and is operated by the power supply inside the station building (primary side), a relay drive circuit that drives the relay when a fault occurs, and the relay drive circuit that operates when the power inside the device (secondary side) is cut off. An alarm output circuit comprising: a diode for driving a relay;