RU165101U1 - RECOGNITION ALARM RECOGNITION DEVICE IN THE FIRE ALARM SYSTEM IN THE FIRE ALARM SYSTEM - Google Patents

Abstract

A device for recognizing alarms of detectors in an alarm loop in a fire alarm system containing a constant voltage source, an instruction input unit, an indication unit, an alert unit including a controller having a signal comparison unit and connected by one of its inputs to the output of the command input unit and its corresponding outputs - to the display unit and to the notification unit, the main voltage divider connected by its inputs to the corresponding outputs of the constant voltage source, and by its output - to the corresponding input of the controller, and an additional voltage divider connected by its inputs to the corresponding outputs of the DC voltage source, and by its output to the corresponding input of the controller, the additional divider with its corresponding input connected to the signal loop, characterized in that the main voltage divider is made in in the form of a resistive divider with a constant transmission coefficient, and an additional voltage divider is made in the form of a resistive divider with a variable coefficient transmission coefficient formed by series-connected resistors and has an input designed for parallel connection of the signal loop, which is a variable resistance for an additional resistive divider, and according to the results of comparison in the controller of signals received from a voltage divider with a constant transmission coefficient and an additional resistive divider with a variable coefficient transmission, the controller determines the presence and number of triggered detectors.

Description

The proposed utility model relates to the technique of electric fire alarm and can be used to detect a fire in the fire alarm system, as well as in security and fire alarm systems.

Most electrical fire alarm devices measure the voltage drop across the alarm loop.

A known fire alarm system, which includes many individual alarm devices connected to a two-wire electrical circuit; each alarm device includes a unidirectional current-carrying means, resistive impedance and a switch configured to move to an excited position in response to a detected fire or other ignition factor (temperature, smoke, etc.). The device has a voltage divider, one part of which is formed on the resistive resistance element and a bi-directional voltage source. The fire alarm can be distinguished from all other signals generated by the system, as during normal operation (no fire), the voltage drop across the resistive resistance element does not change during polarity reversal, and in case of fire, the voltage drop when using the first polarity is different from the voltage when using the second polarity (US patent US 832678, G08B 25/01, 1974).

The disadvantage of this device is its complexity and high cost.

A device for alarming is known, which contains a two-wire loop with a control resistor located on the guarded object, connected to a power source in series with a reference resistor, a threshold element, the output of which is connected to a key input in the actuator circuit, a differential amplifier, two integrators and a polar detector, inputs integrators and a polar detector are connected to the connection point of the loop with the reference divider, the output of the first integrator and one output of the polar detector is connected to one input of the differential amplifier, the output of the second integrator and another polarity output of the detector is connected to another input of the differential amplifier, whose output is connected to the input of the threshold element. The operation occurs when the voltage exceeds a certain threshold voltage determined by the balancing resistor. The device is triggered in all cases when the input signal changes in a time less than the time constant of the integrators (ed. Certificate of the USSR No. 742994, G08B 17/12, 1980).

The disadvantage of this device is that the device only responds to short-time signals, which reduces the reliability of determining the occurrence of a fire.

Fire alarm devices are known that respond only to long-time signals, but not to short ones. This is, for example, a fire alarm device in which the signals of the signal loop sensors amplified by a normalizing amplifier are fed to a threshold element. If the amplitude of the input signal for triggering a threshold element is exceeded, the latter generates a signal corresponding to a logical unit arriving at the integrating link, the time constant of which is selected on the order of 10 seconds. Thus, at the output of the integrating link after a time equal to 10 seconds, a logical unit will be established, provided that the signal level at the output of the normalizing amplifier does not fall below the threshold level of the threshold element. From the output of the integrating link, this signal is fed to the element And, the second input of which is connected through a voltage divider to the output of the normalizing amplifier. When the AND element is triggered, its signal arrives at the input of the integrating link with a time constant of 10 seconds. The logic level signal from the output of the integrating link sets the display unit to the FIRE mode. If the loop is broken or shorted, an EMERGENCY command is generated. The device is locked modes on the basis of the first triggered, i.e. if at the beginning an EMERGENCY was developed, then the FIRE command is not generated and vice versa (ed. certificate of the USSR No. 1795493, G08B 17/10, 1993).

The disadvantage of the device is that signals less than 10 seconds are considered random or false, i.e. the device responds only to long signals, which reduces the reliability of determining the occurrence of a fire.

All the described devices evaluate the fact of a fire by the first triggered fire detector in the alarm loop and at the same time do not distinguish the number of triggered alarm loop detectors, which does not exclude false alarms of a fire alarm and, accordingly, reduces the reliability of determining the occurrence of a fire situation at a controlled facility.

This drawback is partially eliminated in the fire alarm system containing a constant voltage source, a voltage divider connected with its outputs to the corresponding outputs of the constant voltage source, a controller connected with its first input to the output of the command input node and its second input to the output of the voltage divider, an indication node connected its input to the first output of the controller, the notification node connected to its input to the second output of the controller, the additional divider is voltage Ia, connected with its findings to the corresponding outputs of the DC voltage source and included in the open circuit of the additional voltage divider of the conclusions of the fire alarm loop. The maximum total current consumed by the detectors is limited by the resistors of the additional divider (patent for utility model of the Russian Federation No. 127978, G08B 17/10, 2013).

The disadvantage is the lack of reliability of the device due to the influence of factors on the response of the device. When the alarm loop is not connected, the current in the open circuit does not flow and the signal from the output of the additional divider does not enter the analog-to-digital converter of the controller. In this case, the signal on the analog-to-digital converter of the controller depends to a large extent on the controller's own operating parameters, as well as on the external electromagnetic environment, since in the event of a break, the part of the additional divider connected to the analog-to-digital converter of the controller acts as an antenna. Also, in the event of a short circuit on the signal loop, the analog-to-digital converter of the controller may fail due to exceeding the permissible current flowing through the additional divider.

The objective of the utility model is to increase the reliability of recognition of alarm signals from alarm loop detectors, by eliminating the factors of operation of the device itself.

The problem is solved in that in a device for recognizing alarms of detectors in an alarm loop in a fire alarm system containing a constant voltage source, an instruction input unit, an indication unit, an alert unit including a controller having a signal comparison unit and connected to one of its inputs by an output the command input node and its corresponding outputs - to the display node and to the notification node, the main voltage divider connected by its inputs to the corresponding outputs of the source DC voltage, and its output - to the corresponding input of the controller, and an additional voltage divider connected with its inputs to the corresponding outputs of the DC voltage source, and its output - to the corresponding input of the controller, and the additional divider with its corresponding input is connected to the alarm loop, the main voltage divider made in the form of a resistive divider with a constant transmission coefficient, and an additional voltage divider made in the form of a resistive divider with a variable transmission coefficient, formed by series-connected resistors, and has an input designed for parallel connection of the signal loop, which is a variable resistance for an additional resistive divider, and according to the results of comparison in the controller of signals received from a voltage divider with a constant transmission coefficient and an additional resistive divider with variable transmission coefficient, the controller determines the presence and number of triggered detectors.

A patent search showed that the claimed combination of features is new.

The implementation of the main voltage divider with a constant transmission coefficient, and an additional divider in the form of a resistive divider with a variable transmission coefficient formed by series-connected resistors, in parallel with which an alarm loop is connected, which is a variable resistance for an additional resistive divider, allows the controller to receive two analog signals. The presence and number of detectors activated in the alarm loop is determined by simultaneously measuring the voltages at the outputs of the main divider, which is the reference and additional resistive divider, the signals from the outputs of which are fed to the first and second inputs of the controller. These signals are equally dependent on the DC voltage source and differ only due to the signal loop connected to the additional divider. In the analog-to-digital converter of the controller, these two analog signals are digitized. The difference of the received digitized values is determined. This difference obtained in the controller is proportional only to the current total resistance of the alarm loop and does not depend on the properties and characteristics of the voltage source and other components of the fire alarm system. Based on this value, the controller determines the presence and number of triggered detectors in the alarm loop.

The proposed technical solution is illustrated by drawings, which show:

- in FIG. 1 is a functional diagram of a device for recognizing alarms of detectors in an alarm loop in a fire alarm system;

- in FIG. 2 is a circuit diagram of a device for recognizing alarms of detectors in an alarm loop with normally open detectors;

- in FIG. 3 is an electrical diagram of a device for recognizing alarms of detectors in an alarm loop with normally closed detectors.

The device comprises a controller 1, a main voltage divider 2, connected by its output to the corresponding input of the controller 1, an additional voltage divider 3, connected by its output - to the corresponding input of the controller 1, and connected to the signal loop 4 with its corresponding input (Fig. 1). Controller 1 contains an analog-to-digital converter and has in memory a set of typical values of possible signals: “FIRE”, “WARNING”, etc., and a device for comparing typical values of possible signals with those that come from the signal loop. The main voltage divider 2 is made in the form of a resistive divider with a constant transmission coefficient, and the additional voltage divider 3 is made in the form of a resistive divider with a variable transmission coefficient. The divider 3 is formed by series-connected resistors, in parallel with which a signal loop 4 is connected, which is a variable resistance for an additional resistive divider 3 (Fig. 2, 3).

To explain the operation of the claimed device for recognizing alarms of detectors in an alarm loop in a fire alarm system and its connection with the system, FIG. 1 also shows a constant voltage source 5, an instruction input unit 6, an indication unit 7, an alert unit 8, related to the fire alarm system as a whole (Fig. 1). The detector recognition device for alarms of detectors in the alarm loop, which is the subject of patenting, in FIG. 1 is indicated by a dashed line. The signal comparing unit of controller 1 is connected by one of its inputs to the output of the command input unit 6 and its corresponding outputs to the indication unit 7 and to the notification unit 8. The main voltage divider 2 is connected by its inputs to the corresponding outputs of the constant voltage source 5. Additional voltage divider 3 connected by its inputs to the corresponding outputs of the DC voltage source 5. The voltage dividers 2 and 3 are connected to the same DC voltage source 5 (Fig. 1), which eliminates the effect of the output voltage of the voltage source goes to the measured signals in dividers 2 and 3, since the digital value of the total resistance of the signal loop is determined on the basis of digital values from both dividers 2 and 3. Dividers 2 and 3 can consist of any number of constant resistors (Fig. 2 and Fig. 3). The alarm loop is a variable resistance for an additional divider 3 (Fig. 1, 2, 3). The device operates as follows.

Voltage source 5 supplies power to the main 2 and additional 3 voltage dividers, regardless of the presence of a connected signal loop 4. The connected signal loop 4, with its current total resistance, changes the transmission coefficient of the additional divider 3. The signals from the outputs of the dividers 2 and 3 are fed to an analog-to-digital converter controller 1. After digitization, two values from the primary and secondary dividers, equivalent to the analog signals at the outputs of the dividers, are normalized (for example, from The digital value of the output signal of the additional divider 3) is subtracted from the background value of the output signal of the main divider 2), the result is a digital value proportional only to the total resistance of the loop 4. This value by the controller 1 in the device for comparing typical values is alternately compared with the standard ones stored in the memory of the controller 1 (" expected ") values corresponding to the total resistance of the signal loop for various modes of its operation. As a result of this comparison, the controller 1 determines whether the current measured resistance of the alarm loop 4 is one (and only one) of the possible loop operation modes, i.e. it recognizes the current mode of operation of the alarm loop 4, and, depending on this, generates control signals to the indicating unit 7, the warning unit 8, and waits for the possible arrival of control signals from the command input unit 6. Each new change in the total resistance of the loop 4 (new or next operation detectors, violation of the integrity of the trunk) causes a change in the transfer coefficient of the additional divider 3. This is fixed by the controller 1 as described above.

In FIG. 2 is a diagram of a device for recognizing alarms of detectors with a diagram of a connected alarm loop with normally open detectors. The loop consists of the maximum possible number of detectors, which is limited by their total current consumption. In this particular example, the alarm loop consists of four detectors (S ₁ , S ₂ , S ₃ , S ₄ ) and the resistors connected in series with them (R ₆ , R ₇ , R ₈ , R ₉ ). The detectors together with the corresponding resistors are connected in parallel to each other and to the terminal resistance R _K (Fig. 2).

In FIG. 3 is a diagram of a device for recognizing alarms of detectors with a circuit of an alarm loop with normally closed detectors. The loop also consists of the maximum possible number of detectors, which is determined by their internal resistance in standby mode (in the absence of operation). In this particular example, in parallel to each detector (S ₅ , S ₆ , S ₇ , S ₈ ), threshold-generating resistors (R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ ) are connected. Pairs of detectors with corresponding resistors are connected in series to each other and to the terminal resistance R _K (Fig. 3).

Loop circuits are given in order to show that the claimed device can work with various loop circuits. Variants of signal loop circuits and their connection (Fig. 2 and Fig. 3) are not subject to patenting.

An example of the operation of the device for recognizing alarms of detectors in the alarm loop in the fire alarm system in accordance with the alarm loop with normally open detectors (Fig. 2) is explained below.

When one of the fire detectors, for example, S ₁ , is triggered, its internal resistance decreases stepwise and becomes comparable to the value of the additional resistance R ₆ , which ensures the inclusion of the first additional resistance R ₆ to the internal resistance of the first fire detector S ₁ . Thus, in the fire alarm loop 4, the total resistance decreases and, accordingly, the voltage on the fire alarm loop 4 decreases. As a result, on the resistor R _{5 of the} additional divider 3, the voltage changes and goes to the input of the controller 1. On the resistor R _{2 of the} main divider 2, there is always a voltage that goes to the corresponding input of the controller 1. A digital value of this current voltage is generated every time a digital value is generated voltage received from the additional divider 3. In controller 1, based on these two received digital values, the digital value of the current total resistance nufa 4, which does not depend on the voltage of the power source 5 or any of its fluctuations. This value is compared with the stored (“expected”) values from the memory of the controller 1 and according to the principle of determining the state of the loop 4, its current state is determined, in this case, the operation of one detector and can be considered as, for example, ATTENTION.

When, for example, the second next fire detector S _{2 is} triggered, a second pair of resistances is connected: the additional resistance R ₇ and the internal resistance of the activated fire detector S ₂ , in parallel with the previously activated fire detector S ₁ and its additional resistance R ₆ and end resistance R _K. The total resistance of the loop 4 is further reduced, which again affects the voltage supplied to the controller 1 from the resistor R _{5 of the} additional voltage divider 3. After the corresponding conversions and calculations, similar to the operation of the first fire detector S ₁ and taking into account the already activated detector, the controller 1, the loop operating mode is determined, which corresponds to the presence of two triggered detectors and can be considered as, for example, FIRE.

An example of the operation of the device for recognizing alarms of detectors in the alarm loop in the fire alarm system in accordance with the alarm loop with normally closed detectors (Fig. 3) is explained below.

When one of the fire detectors is triggered, for example, S ₅ , its internal resistance increases stepwise or even becomes infinitely large, which enables the inclusion of the first additional resistance R _{10 in} series with the resistance R _K. Thus, in the fire alarm loop 4, the total resistance increases and, accordingly, the voltage on the loop 4 increases. As a result, the voltage changes on the resistor R _{5 of the} additional divider 3 and goes to the input of the controller 1. There is always voltage on the resistor R _{2 of the} main divider 2, which is supplied to the corresponding input of the controller 1. The digital value of this current voltage is generated each time a digital value of the voltage received from the additional divider is generated I 3. In controller 1, based on these two received digital values, the digital value of the current total resistance of loop 4 is calculated, which does not depend on the voltage of power supply 5 or any fluctuations of it. The obtained value is compared with the stored ("expected") values from the memory of the controller 1 and according to the principle of determining the state of the loop 4, its current state is determined, in this case, the operation of one detector and can be considered as, for example, ATTENTION.

When, for example, the second next fire detector S _{6 is} triggered, a second additional resistance R _{11 is} connected in series to the previously activated fire detector S ₅ and its additional resistance R ₁₀ and terminal resistance R _K. The total resistance of the loop 4 increases even more, which again reflects on the voltage supplied to the controller 1 from the resistor R _{5 of the} additional voltage divider 3. After appropriate conversions and calculations, it is similar to the operation of the first fire detector S ₅ and taking into account the already triggered detector, the controller 1, the loop operating mode is determined, which corresponds to the presence of two triggered detectors and can be considered as, for example, FIRE.

If it is necessary to control several alarm loops, the proposed device additionally provides for the required number of additional dividers identical to the first, parallel to each of which one of the alarm loops is connected, and the outputs of the additional voltage dividers are connected to the corresponding inputs of the controller and the outputs of the voltage source.

In the proposed device for recognizing alarm signals of detectors in an alarm loop in a fire alarm system, the controller determines the presence and number of triggered detectors in an alarm loop according to the results of comparison in the controller of signals received from the main voltage divider, additional resistive divider. The proposed device for recognizing alarm signals of detectors in an alarm loop in a fire alarm system provides the necessary and sufficient number of comparisons of expected digital values and digital values obtained as a result of measuring voltage changes in a fire alarm loop. In accordance with their processing, the device reduces the number of false alarms of the fire alarm system as a whole and provides higher reliability and information content in determining the fire situation.

The proposed device increases the reliability of recognition of alarm signals of detectors (determining the operation of multiple detectors) alarm loop, by eliminating the factors of the device itself and ensuring the dependence of the signal only on the alarm loop.

Claims (1)

A device for recognizing alarms of detectors in an alarm loop in a fire alarm system containing a constant voltage source, an instruction input unit, an indication unit, an alert unit including a controller having a signal comparison unit and connected by one of its inputs to the output of the command input unit and its corresponding outputs - to the display unit and to the notification unit, the main voltage divider connected by its inputs to the corresponding outputs of the constant voltage source, and by its output - to the corresponding input of the controller, and an additional voltage divider connected by its inputs to the corresponding outputs of the DC voltage source, and by its output to the corresponding input of the controller, the additional divider with its corresponding input connected to the signal loop, characterized in that the main voltage divider is made in in the form of a resistive divider with a constant transmission coefficient, and an additional voltage divider is made in the form of a resistive divider with a variable coefficient transmission coefficient formed by series-connected resistors and has an input designed for parallel connection of the signal loop, which is a variable resistance for an additional resistive divider, and according to the results of comparison in the controller of signals received from a voltage divider with a constant transmission coefficient and an additional resistive divider with a variable coefficient transmission, the controller determines the presence and number of triggered detectors.

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