JPS6057023B2 - Disconnection/short circuit detection circuit for smoke prevention control equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disconnection/short circuit detection circuit for a smoke prevention and exhaust control device.

Generally, in this type of smoke prevention and exhaust control equipment, if a disconnection or short-circuit failure occurs in the control line of the disaster prevention equipment, the disaster prevention equipment will be rendered useless in the event of a fire outbreak. Even in the event of a failure, a large short-circuit current will flow, which may cause the fuse in the control device to blow, rendering the entire control line unusable.

Conventionally, when detecting abnormalities in control lines, a tester was used to check each line, but it was difficult to identify disconnection failures with a tester, the checking process was cumbersome, and constant monitoring was not possible. It had a drawback. The present invention aims to solve the above-mentioned drawbacks. Examples will be described below using figures.

FIG. 1 shows a schematic configuration diagram of the smoke prevention device according to the present invention. Reference numerals 5 and 50 are fire detectors installed in each area, and the outputs of the fire detectors 5 and 5n are District relays X1 to Xn are driven, and when a fire occurs in any district, the fire detector Sn installed in that district is activated, district relay Xn is activated, and relay contact xn is activated. is closed, and power E is applied to the disaster prevention equipment Mn in the area where the fire occurred via the control line Ln, so that the disaster prevention equipment Mn is activated. x,'~xn' is the control line L-Ln
This is the relay contact of the control line cutoff relay inserted in the circuit, and is controlled by the output of the disconnection/short circuit detection circuit C.
In the figure, Lc', L,' to Ln' are detector wirings. Second
The figure shows a disconnection/short circuit detection circuit for one control line according to the present invention, in which a diode D is connected between the end of the control line L of the disaster prevention equipment M and the common control line Lc, and a pulse generation circuit PG is connected to the control line L. The alternating pulse voltage generated by the current limiting resistor R
, and a short-circuit detection circuit DA operates when a pulsating pulse is no longer obtained at the application point A of the alternating pulse voltage, and a disconnection detection circuit DB operates when the alternating pulse voltage appears at this application point. It has been established that R2 in the diagram
, R is the resistance. The operation of the embodiment will be explained below.

If there is no disconnection or short circuit failure in the control line L, the alternating pulse voltage as shown in Figure 3a applied to point A will be half-wave rectified by the diode D that terminates the control line L.
The voltage at the application point A becomes a pulsating pulse voltage as shown in FIG. 1 and y2 are opened, the short-circuit failure indicator lamp LA does not light up, and the normally closed contact X'' of the control line cutoff relay X'' is also closed. At this time, the disconnection detection circuit DB (7) FET T2 is reverse biased, FET T2 is in a slightly disconnected state, and the disconnection relay Z
is not driven, the normally open contacts Zl and Z2 are open, the disconnection indicator lamp LB does not light up, and the control line cutoff relay As shown in FIG. 3d, the pulsating pulse voltage is no longer applied to the application point A of , the transistor T1 becomes temporarily disconnected, and the short-circuit relay Y returns to normally closed contact, ?1
.
Therefore, because one control line is short-circuited, the common control line Lc
Fuse F inserted into the circuit will not blow and all control lines will become unusable. Furthermore, when a disconnection fault occurs in the control line L, an alternating pulse voltage as shown in FIG.
is driven and the normally open contacts Zl and Z2 are closed, which lights up the disconnection indicator lamp LB. At the same time, the control line cutoff relay X'' is driven, so the normally closed contact X'' is opened and the control line L is connected. Power supply E is not applied. Although the transistors T1 and FET T2 are turned on in a pulsed manner and the relays Y and Z are driven in a pulsed manner, chattering does not occur if the frequency of the alternating pulses is appropriately set. Also transistor T1 and FET
It goes without saying that a time constant circuit may be inserted into the input of T2. The present invention is configured as described above, and terminates the control line of the disaster prevention equipment of the smoke prevention and exhaust control device with a diode, and applies an alternating pulse voltage to the control line via a resistor, thereby creating a short circuit detection circuit and a disconnection detection circuit. The circuit detects changes in the pulse voltage at the point where the alternating pulse voltage is applied to detect short circuits and disconnections in the control line. Therefore, the alternating pulse voltage is rectified by the diode terminating the control line. If a pulsating pulse voltage appears at the applied point, the control line is normal; if the pulsating pulse voltage is no longer obtained, it can be determined that the control line is short-circuited; When voltage appears at the application point, it can be determined that the control line is disconnected, and in this way, three states can be digitally determined: when a pulsating pulse voltage appears, when an alternating pulse voltage appears, and when it does not appear. Can be judged.

Moreover, since the judgment can be made digitally, the influence of line resistance etc. is extremely small and the detection method is simple. This has the advantage of improving the reliability of the smoke prevention and exhaust control system because the control line is constantly monitored.Also, disconnections and short-circuits in control lines can be immediately identified, so it is possible to take appropriate measures to deal with the failure. It has the advantage that treatment can be performed quickly.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a smoke prevention device according to the present invention, FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of the same operation. S1 to Sn are fire detectors, M, Ml to Mn are disaster prevention equipment,
L, Lc, Ll~Ln are control lines, D is a diode, R1
are resistors, A, Al to An are alternate pulse application points, DA is a short circuit detection circuit, and DB is a disconnection detection circuit.

Claims (1)

[Claims] 1. In a smoke prevention and exhaust control device that controls disaster prevention equipment such as multiple fire doors and smoke exhaust vents through the operation of a fire detector, the control lines for each of the disaster prevention equipment mentioned above are terminated with diodes, and the control lines are connected through current limiting resistors. and a short-circuit detection circuit that operates when an alternating pulse voltage is applied to the application point and a pulsating pulse voltage is no longer obtained at the application point, and a disconnection detection circuit that operates when an alternating pulse voltage appears at the application point. Open/short circuit detection circuit for smoke control equipment.