JPH0432438B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information transmission system used in fire alarm systems, smoke prevention systems, and the like.

FIG. 1 is a block diagram showing an information transmission system in a conventional automatic fire alarm system. In the figure, when any one of the plurality of sensors S ₁ , S ₂ . . . operates, a relay X operates, and its output contact operates a bell, an indicator, etc. However, when a certain sensor S ₁ operates, a signal having a natural frequency of ₁ is generated from the oscillator T ₁ ', and this signal is conveyed and superimposed on the transmission line by capacitor coupling, and
On the receiver side, the frequency component is similarly extracted by capacitor coupling, the frequency discrimination circuit 1 discriminates the signal of the natural frequency ₁ , and the address display circuit 2
The address of sensor _S1 is displayed at . However, in the information transmission system using such natural frequencies, it is difficult to change the natural frequencies, and it is necessary to prepare transmitters and filters for each of the many natural frequencies, resulting in poor productivity. . Conventionally, as shown in FIG _{. 2} , pulse code transmitting circuits _{T 1} , _{T 2 . 2} The voltage detection circuit 3 detects the different pulse code signals generated from the pulse code transmission circuits T ₁ , T ₂ ... during the operation of ...
The code processing circuit 4 detects and discriminates the above pulse code by replacing it with a change in the DC voltage, and the address display circuit 5 detects the operating sensor S ₁ , S ₂
A point address system has been proposed that displays addresses of... However, in the case of such a point address method, changes in the voltage level or current level transmitted from the sensor to the receiver can be used to distinguish, for example, between a preliminary alarm and a main alarm, or to transmit the detected smoke concentration. However, there was a problem in that information based on level changes and information based on pulse codes could not be used together.

The present invention has been made to solve these problems of the conventional example, and transmits a level signal whose level changes in multiple stages from a disaster prevention sensor to a receiver to generate a preliminary warning and a main warning. To provide an information transmission system that enables the discrimination of smoke and the transmission of detected smoke concentrations, and also enables the transmission of self-diagnosis commands from a receiver to a disaster prevention sensor via a signal transmission line. The purpose is to

The configuration of the present invention will be described below with reference to illustrated embodiments. FIG. 3 is a block diagram showing a disaster prevention monitoring system using an information transmission system according to an embodiment of the present invention. As shown in the figure, a two-wire fire alarm line 7 derived from a central monitoring and control unit 6, which is a receiver, includes:
A standard sensor such as a general smoke detector 8 and an intelligent disaster prevention sensor such as an intelligence sensor 9 having a self-check function and a linear information sending function are mixed. The control and monitoring line 10 has a two-wire power supply line and a two-wire signal transmission line, and is a monitoring and control terminal repeater for starting and controlling the smoke prevention system ER and fire alarm bell B. 11. A control command CD is then sent from the central supervisory control device 6 to each supervisory control terminal repeater 11, and conversely, an operation confirmation signal RT is sent from each supervisory control terminal repeater 11 to the central supervisory control device 6. It's becoming like that. Furthermore, a self-check signal SC for the intelligence sensor 9, that is, a self-diagnosis command, is sent from the central monitoring and control device 6 to the fire alarm line 7 as a transmission signal consisting of a pulse code. For the supervisory control device 6,
A detection level signal DL is sent out. That is, the intelligence sensor 9 has a self-check function using a transmission signal consisting of a pulse code signal and a three-level smoke concentration detection function. Self-check function uses self-check signal
This function uses SC input to put the internal circuit in the same state as when smoke is detected. In addition, the 3-level smoke concentration detection function is a function that distinguishes and detects smoke concentrations of, for example, 5%, 10%, and 15%, and the detection level signal DL, which changes level in stages according to each smoke concentration, is a voltage level. It is now being transmitted as a signal. FIG. 4 shows an example of a signal waveform transmitted over the fire alarm line 7. As shown in the figure, a voltage signal in which a small pulse code signal is superimposed on a voltage level signal is transmitted over the fire alarm line 7. is being transmitted. The central monitoring and control device 6 identifies the multi-step voltage level signals transmitted on the fire alarm line 7 and issues an alarm corresponding to each voltage level signal. There are two types of alarms: a preliminary alarm and a main alarm. In the preliminary alarm, only the fire warning light on the display 12 of the central monitoring and control unit 6 lights up and a fire warning signal sound is emitted. In the event of an alarm, the fire alarm bell B in each area will ring and the smoke prevention system ER will be activated. Of the three levels of smoke detection concentration mentioned above, which level corresponds to the preliminary alarm and the main alarm can be set using the operation unit 13.
Further, control patterns such as which load is to be operated among the loads connected to the control monitoring line 10 when the main alarm is issued can also be set using the operation unit 13.

The present invention is configured as described above, and includes a disaster prevention sensor that sends out a level signal whose level changes in multiple stages according to changes in the sensing state, and a disaster prevention sensor that identifies the multi-stage level signals and responds to each level signal. A receiver that generates an alarm is connected via a two-wire signal transmission line, and a self-diagnosis command for bringing the internal circuit of the disaster prevention sensor into the same state as during sensing operation is superimposed on the level signal and transmitted. Since the smoke detection density can be transmitted from the receiver to the disaster prevention sensor using a pulse code signal, the detected smoke concentration can be transmitted from the disaster prevention sensor to the receiver using a level signal that changes in level in multiple stages. It has the advantage of being able to distinguish between a preliminary warning and a main warning, and also because the self-diagnosis command is transmitted from the receiver to the disaster prevention sensor by means of a pulse code signal superimposed on this level signal. There is an advantage that there is no need to separate the line for transmitting the level signal and the line for transmitting the self-diagnosis command, making it possible to save on the number of lines. In other words, the disaster prevention sensor transmits a multi-level signal that identifies the detected smoke concentration and the type of alarm to the receiver, and the receiver transmits a self-diagnosis command pulse code signal to the disaster prevention sensor. Since a method of superimposing a level signal and a pulse code signal is adopted, it is possible to separate each signal even if both signals are mixed on the signal transmission line. Although the signal transmission line is a two-wire system, it is possible to simultaneously transmit two types of signals for different purposes required for this type of system.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional example, FIG. 2 is a block diagram of another conventional example, FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is an operational waveform diagram of the same. 6 is a central monitoring and control device, 7 is a fire alarm line, and 9 is an intelligence sensor.

Claims (1)

[Claims] 1 A two-wire system connects a disaster prevention sensor that sends out a level signal whose level changes in multiple stages according to changes in the sensing state, and a receiver that identifies the multi-stage level signal and generates an alarm corresponding to each level signal. A pulse code signal is transmitted from the receiver to the disaster prevention sensor by superimposing a self-diagnosis command on the level signal to bring the internal circuit of the disaster prevention sensor into the same state as during sensing operation. An information transmission method characterized by being able to transmit information.