JPH0535981A - Device for testing disconnection detecting function in fire alarm equipment - Google Patents

Abstract

PURPOSE:To rapidly restore a state to be the fire monitoring state after the test of a disconnection detecting function is terminated by providing a switching element in parallel to reception resistance. CONSTITUTION:A switch SW1 for testing the disconnection detecting function is provided in parallel to reception resistance Rr and the switch SW1 is turned on when the line disconnection detecting function by a fire receiver RE1 is tested. That is, the switch SW1 is turned on so that the both end voltages of reception resistance Rr become 0V, the voltage of reception resistance Rr comes to be lower than the reference voltage Vref and the output of a comparator C1 for detecting disconnection changes from 'H' to 'L' which expressed the disconnection of a line. Thus, the line is spuriously made to be a disconnection state and the disconnection detecting function is normal when the receiver RE1 judges that disconnection exists at this time. Here, current is made to flow in a sensor SE from a power source with the switch SW1 and the sensor SE itself keeps the monitoring state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test device for testing a function of a receiver such as a receiver for detecting a disconnection of a line in fire alarm equipment.

[0002]

2. Description of the Related Art In a conventional fire alarm system, a receiver detects that there is a disconnection in each line connected to a fire receiver, and tests whether this disconnection detection function is normal or not. The device shown in FIG. 2 is known as a device for doing so.

In the conventional device shown in FIG. 2, a receiving resistor Rr is connected in series with a fire detector SE connected to each line, and a receiving signal detected by the receiving resistor Rr is used as a reference voltage Vref for detecting disconnection. A disconnection detection comparator C1 for comparing with the above is provided, and a test switch SW for disconnecting the common line LC of the above line from the fire receiver is provided. Then, when the test switch SW is turned off, the voltage across the receiving resistor Rr becomes lower than the reference voltage Vref, and if the comparator C1 detects this, it is recognized that the disconnection detection function of the fire receiver RE is normal. To do. In addition, instead of the switch SW for disconnecting the common line LC of the line from the fire receiver RE, there is also one provided with a switch for disconnecting each signal line of the line from the fire receiver RE, and in this case, the same operation as above is performed. To do.

[0004]

In the above-mentioned conventional example, there is a problem that it takes a long time from the completion of the test of the disconnection detection function to the return of the fire detector to the monitoring state.

That is, in the above conventional example, when the switch SW is turned off when testing the disconnection detection function,
The sensor SE connected to the line is cut off from the power supply,
The sensor SE is in the same state as when the fire recovery operation was performed. Therefore, after that, the test of the disconnection detection function is completed, and even if the switch SW is turned on, the fire detector SW cannot immediately recover to the monitoring state, and after the test of the disconnection detection function is completed (the switch SW is turned on. After 10 seconds, the fire detector SW returns to the monitoring state for the first time.

[0006] It is an object of the present invention to provide a test device for a disconnection detecting function in a fire alarm system, which allows the fire detector to return to the monitoring state immediately after the test for the disconnection detecting function is completed. is there.

[0007]

According to the present invention, a receiving resistor is connected in series with a fire detector, and the presence or absence of line disconnection is determined by comparing the received signal detected by this receiving resistor with a reference voltage. In the fire alarm equipment having the disconnection detection function, a test switching element is provided in parallel with the reception resistance.

[0008]

1 is a circuit diagram showing an embodiment of the present invention. The same members as those shown in the conventional example are designated by the same reference numerals.

A common line LC and a signal line L are connected to the fire receiver RE1, and a large number of fire detectors SE and one terminating resistor Rt are connected between the common line LC and the signal line L. Has been done.

The fire receiver RE1 is provided with a disconnection detection comparator C1 and a fire discrimination comparator C2. The disconnection detection comparator C1 includes a resistor R
The reference voltage Vref for disconnection determination made by 1 and R2 is compared with the received signal from the line (common line LC + signal line L), and the switch SW1 for disconnection detection function test is compared.
When the voltage is turned on, if the voltage across the receiving resistor Rr is lower than the reference voltage Vref, the disconnection detection comparator C1
Outputs "L" indicating the disconnection state, and the disconnection indicator lamp and the buzzer (not shown) are operated by this, and it is determined that the disconnection detection function of the line by the fire receiver RE1 is normal at this time.

Further, a switch SW1 for disconnection detection function test is provided in parallel with the receiving resistor Rr.
W1 is turned on when testing the disconnection detection function of the line by the fire receiver RE1.

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

During normal fire monitoring, the switch SW
Turn off 1. In this case, if the fire detector SE has not detected a fire, a small monitoring current flows through the fire detector SE, and if 30 fire detectors SE are connected in parallel, for example, 1. 35 mA flows, and at this time, the termination resistance Rt (for example, 10 kΩ) is 2.21 m.
A current flows, and as a result, a total current of 3.56 mA flows to the receiving resistor Rr. In this case, the voltage across the reception resistor Rr is about 2V, which is higher than the reference voltage Vref of the disconnection detection comparator C1, so the disconnection detection comparator C1 indicates that the line is not disconnected. "H" is output.

Here, when testing whether the disconnection detection function of the line by the fire receiver RE1 is normal, the switch SW1 is turned on. As a result, the voltage across the receiving resistor Rr becomes 0 V, the voltage of the receiving resistor Rr at this time becomes lower than the reference voltage Vref, and the line is disconnected from the output of the disconnection detection comparator C1 from "H". It changes to "L" indicating that That is, when the switch SW1 is turned on, the line is artificially disconnected, and if it is determined that the receiver RE1 is disconnected at this time, the disconnection detection function is normal.

Then, when the disconnection detection function is being tested, the sensor SE is connected from the power source through the switch SW1.
Since a current flows through the detector SE, the sensor SE itself maintains the fire monitoring state. When the test is completed and the switch SW1 is turned off, the sensor SE maintains the fire monitoring state even during the test, so that the fire alarm facility immediately recovers to the fire monitoring state.

In the above embodiment, the common line LC is 2
In the case of 4V, when the common line LC is negative, when the switch SW1 is turned on, the comparator C
The + input potential of 1 is 24 V, but other operations are the same as above. The switch SW1 is actually an electronic switch using an active element such as a transistor, but it may be a manual switch. ..

[0017]

According to the present invention, in the test device for the disconnection detection function in the fire alarm system, the fire detector can immediately return to the monitoring state after the test of the disconnection detection function is completed. ..

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a circuit for detecting disconnection in a conventional fire receiver.

[Explanation of symbols]

 RE1 ... Fire receiver, C1 ... Disconnection detection comparator, C2 ... Fire discrimination comparator, Rr ... Reception resistance, SW1 ... Disconnection detection function test switch.

Claims (1)

Claim: What is claimed is: 1. A fire resistance detector is connected in series with a reception resistor, and a reception signal detected by the reception resistance is compared with a reference voltage to determine whether or not the line is disconnected. In a fire alarm system having a detection function, a switching device is provided in parallel with the reception resistance, and a test device for a disconnection detection function in the fire alarm system.