JPH0650553B2 - Analog signal output type environmental information detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a detector for detecting the amount of information such as smoke, temperature, and gas in the environment as an analog signal amount, and controlling the obtained signals. It is suitable for use in fire alarm equipment, air conditioning equipment, etc. used as signals.

[Conventional technology]

In fire alarm equipment, air conditioning equipment, etc., the amount of environmental information such as smoke, temperature, and gas is constantly detected and used as various control signal sources. As a detector that obtains this environmental information, a dedicated detector that has been adapted to the application has been used, but a common single detector has been used to eliminate the complexity of installation work and the rise in equipment costs. Is proposed to be used. For example, a temperature detector that withstands temperature in common as an amount of environmental information is disclosed in JP-A-59-91501 (May 2, 1984).
Published 6th). That is, this temperature detector has a circuit configuration as shown in FIG. 5, and uses a platinum resistance temperature detector (50) as a temperature detecting end. The potential of the temperature detecting end is input to the operational amplifier (54) together with the potential of the reference value generating section composed of three series resistors (51, 52, 53) and then amplified. The amplified output is input to the analog / digital converter (55), and the obtained output signal is used for each facility. The specific resistance (52) of the reference value generating section,
A switch (56) for reference value control is connected in parallel,
A switch (58) for controlling the amplification gain is connected in parallel to a specific resistance (57) of the series electric path from the reference value generator to the operational amplifier (54). These switches (56, 58) are connected to the control circuit (5
Opening and closing is controlled by the relay (60) which is energized by the control signal from 9). Therefore, by closing both switches (56, 58) by a control signal from the control circuit (59) to lower the reference voltage and increasing the amplification gain of the operational amplifier (54), the detected temperature of FIG. -As shown by the curve (A) in the output voltage characteristic diagram, it becomes a detector that can obtain an output signal with sufficient resolution in a narrow temperature range of the normal room temperature range, which is suitable for use as a detector for air conditioning equipment. It will be convenient. Also, both switches (56, 58) are opened by the control signal from the control circuit (59) to raise the reference voltage and the operational amplifier.
If the amplification gain of (54) is made small, as shown in the curve (F), it becomes a detector that can obtain a sufficient output voltage in a wide temperature range of high temperature, which is suitable for use as a detector for fire alarm equipment. It will be convenient.

[Problems to be solved by the invention]

In the above-mentioned detector, the control state of the control circuit (59) is referred to determine the detection temperature on the receiving side, and the digital signal sent from the analog-digital converter (55) is detected by this control state. Converted to a value. Then, in order to switch from the normal temperature range that would accompany a fire to an abnormally high temperature range without delay, the receiving side must monitor this detected temperature value without delay and, if necessary, Therefore, processing for prompt switching is required. This process needs to be performed for each detector, and there is a problem that the process becomes extremely complicated on the receiving side that collectively manages a large number of detectors.

[Means for solving problems]

An analog signal output type environmental information detector according to the present invention is
It is possible to select, as an input signal, the output of the detection end for detecting the amount of environmental information including the temperature as in the above-mentioned conventional example as the input signal, and to the detection unit that generates the analog output signal corresponding to the amount of environmental information along the input / output characteristics. Has multiple possible input / output characteristics,
By providing selection means for selecting the input / output characteristic of the detection section in response to a predetermined output signal value of the detection end, and by providing selection status signal generation means for generating a signal indicating the selection status of the selection means. This is a solution to the above problems.

[Action]

An analog signal output type environmental information detector according to the present invention is
Since the above-mentioned means is provided, when the input signal value of the detector reaches a predetermined signal value, the selection means selects and switches a predetermined input / output characteristic from a plurality of input / output characteristics, and A signal indicating which input / output characteristic the selection means is currently selecting is sent from the selection status signal generation means.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment in which the analog signal output type environment information detector of the present invention is applied to a temperature detector.

In FIG. 1, the analog signal output type environmental information detector is roughly classified into a platinum resistance temperature detector (10) as a temperature detecting end.
And a processing circuit (100) and a selection means (200).

The processing circuit (100) has a plurality of selectable input / output characteristics, and the maximum value of a predetermined input / output characteristic of each input / output characteristic overlaps with or is consistent with the minimum value of the next input / output characteristic in a certain range. As described above, the detection signals from the platinum resistance temperature detector (10) can be amplified with one selected input / output characteristic. That is, the processing circuit (100)
Are resistors (11, 12, 13, 16), operational amplifier (14), switch (15, 1).
It is equipped with 7) and is connected as follows. The potential from the platinum resistance thermometer (10) is applied to the (+) input terminal of the operational amplifier (14), and the voltage of the reference value generating section consisting of three series resistors (11, 12, 13) is the operational amplifier. Inputs are made to the (-) input terminals of (14). A switch (15) is connected in parallel with the resistor (11). A switch (17) is connected in parallel to a specific resistor (16) that sets the amplification gain. By these resistors (11, 16) and switches (15, 17), the input / output characteristics will be sequentially arranged so that the maximum value of the predetermined input / output characteristics becomes the minimum value of the other input / output characteristics. .

Further, the selection means (200), when the detection signal from the platinum resistance temperature detector (10) exceeds the range of one input / output characteristic,
It is possible to output a selection signal for selecting the next input / output characteristic with hysteresis and generate a signal indicating the selection status. That is, the selecting means (200) includes an operational amplifier (18), a comparator (19), and resistors (20, 21, 24), which are connected as follows. The potential from the platinum resistance thermometer (10) is amplified by the operational amplifier (18), and then the comparator (19).
It is supplied to the (-) input terminal of. Further, the inversion level set by the inversion level setting section composed of the series resistors (20, 21) is input to the (+) input terminal of the comparator (19). Further, the comparator (19) has a low level (a signal indicating that the selection situation has changed) when the output potential from the operational amplifier (18) exceeds the inversion level.
Can be output from the output terminal (22). A resistor (24) is connected between the output terminal and the (+) input terminal of the comparator (19) so that the input and output have hysteresis.

A control circuit (23) including a relay is connected between the output terminal of the comparator (19) and the power supply line. This control circuit (23) operates when the comparator (19) goes to a low level to open the switch (15) for reference value control, and the switch (17) for amplification gain control. ) Can be closed. As a result, the processing circuit (100) is changed from one input / output characteristic to the next input / output characteristic.

In the embodiment in which the analog signal output type environmental information detector according to the present invention configured as described above is used as a temperature detector, the output of the comparator (19) is at a high level at a temperature as low as 10 to 30 ° C. The control circuit (23) closes the switch (15) for reference value control and the switch (17) for amplification gain control. As a result, the input / output characteristics of the detector from the temperature detecting end to the output of the operational amplifier (14) are as shown by the curve (A) in FIG. That is, in FIG. 2, the horizontal axis represents temperature as an input, and the vertical axis represents the output of the operational amplifier (14) as an output. Shows.
In addition, in FIG. 2, (a) shows the case where the maximum value of the input / output characteristic and the minimum value of the next input / output characteristic match, and (b) shows the maximum value of the input / output characteristic and the next input / output characteristic. The case where the minimum values overlap in a predetermined range is shown, and (c) shows the case where the next input / output characteristics are selected with a hysteresis and overlap. The characteristic as shown by the curve (A) is a characteristic suitable for use as a detector for air conditioning equipment because an output signal with high resolution is usually obtained in the room temperature range.

When the detected temperature further rises, the comparator (19) inverts to the low level at the predetermined temperature (t1) and its output terminal (2
From 2), the control circuit (23) opens the switch (15) for controlling the reference value, and the switching circuit for controlling the amplification gain while generating a signal indicating that the selection status of the selecting means has changed. Bowl (17)
Close. As a result, the input / output characteristics of the detector become as shown by the curve (F) in Fig. 2, and an output signal can be obtained over a wide temperature range of high temperature, making it suitable for use as a detector for fire alarm equipment. It becomes a characteristic.

As described above, the temperature detector according to the present invention generates a signal indicating which characteristic is selected from the plurality of input / output characteristics of the detecting section in addition to the analog output signal of the detecting section. The receiving side can determine the detected temperature by referring to both signals.

Next, when the detected temperature of the detector in the high temperature region as shown by the curve (F) decreases and reaches a predetermined temperature (t2), the output of the comparator (19) is inverted. Since the comparator (19) has a hysteresis characteristic, it reverses at a temperature (t2) lower than the temperature (t1) that reverses when the detected temperature falls as described above.

This prevents the comparator (19) from repeating the inversion operation in the vicinity of the same temperature at which it inverts, so that the operation of the entire detector becomes stable.

In the above embodiment, the analog signal output type environmental information detector according to the present invention was used as a temperature detector, but an embodiment using this as an ionization type smoke detector is shown in FIG.

That is, the ionization chamber (31) whose inside is ionized by the radiation source (30) is used as the smoke detection end. The ionization chamber (31)
It is composed of an internal ion chamber (31a) where the outside air that has been ionized by the radiation source (30) does not easily enter, an external ion chamber (31b) where the outside air can freely flow, and an intermediate electrode connected to a field effect transistor (FET). Has been done. A small current is flowing in each ion chamber, and when smoke enters the outer ion chamber (31b), the ion current decreases, that is, the impedance in the outer ion chamber (31b) rises, and along with that, the intermediate electrode When the voltage rises, the increase in impedance is used as a potential change to generate an analog signal from the detection signal generating section composed of two series resistors (32, 33). As described above, the ionization chamber (3
The detection section is formed from 1) to the detection signal generation section. The change of the input / output characteristic of the detection unit is performed by changing the respective terminals (a, a) drawn from the two series resistors (32, 33) forming the detection signal generating unit.
The selection is performed by the switch (34) in b). The electric potential at the smoke detection end is input to the-terminal of the comparator (35).
At the + terminal of the comparator (35), two series resistors (36, 37) for setting the level at which the output of this comparator (35) is inverted.
Is connected to the inversion level setting section. This comparator (35) is also a selection status signal generating means, and its output terminal
(38) is a signal terminal indicating the selection status. Between the output terminal of the comparator (35) and the positive terminal of the power supply, the above switching device (34)
A control circuit (39) including a relay for switching control is connected. And this comparator (35) also has a feedback resistor
(40) is connected to give a hysteresis characteristic.

In the embodiment shown in FIG. 3, the processing circuit (100) has a resistor (32,3).
3) and switch (34), the selection means (200) is a resistor
It consists of (36,37,40) and comparator (35).

In the embodiment in which the analog signal output type environmental information detector according to the present invention configured as described above is an ionization type smoke detector, the output of the comparator (35) is at a high level when the smoke concentration in which almost no smoke is present is low. And the control circuit (3
9) switches the switch (34) to the a contact side. As a result, the input / output characteristics of the detector are as shown by the curve (A) in FIG. Here, in FIG. 4, the smoke concentration as an input is plotted on the horizontal axis, and the output of the switching terminal (41) of the switch (34) is taken as the output on the vertical axis, so that the detection by the ionization type smoke detector The input / output characteristics of the parts are shown. As shown in the curve (A), in the low concentration condition where almost no smoke exists, a high-resolution output signal can be obtained from the detector, so as a detector for air conditioning equipment that detects the degree of air pollution. This property is suitable for use.

When the smoke density further rises, the comparator (35) inverts to a low level at a predetermined density (d1), and its output terminal (38)
Generates a signal indicating that the selection status of the selecting means has changed, and the control circuit (39) switches the switch (34) to the b contact side. As a result, the input / output characteristics of the detector are
As shown by the curve (F) in FIG. 4, the output signal can be obtained over a wide concentration range of high concentration, which is a characteristic suitable for use as a detector for fire alarm equipment.

In this way, the ionization type smoke detector according to the present invention generates a signal indicating which characteristic is selected from a plurality of input / output characteristics of the detecting section in addition to the analog output signal of the detecting section. Therefore, the receiving side can determine the detected smoke density by referring to both signals.

In this ionization type smoke detector as well as the above temperature detector, since the comparator (35) has a hysteresis characteristic, the concentration (d2) lower than the concentration (d1) that is reversed when the detected smoke concentration decreases is increased. ). Therefore, the comparator (3
Since the inversion operation is prevented from being repeated in the vicinity of the same concentration at which 5) is inverted, the operation of the entire detector becomes stable.

In the above embodiment, the temperature detector using the platinum resistance temperature detector as the detection end, or the ionization type smoke detector using the ionization chamber has been described, but as the detector, other photoelectric smoke detectors, Needless to say, the invention can be applied to a gas detector or a humidity detector.

[Advantages of the Invention] As described above, the analog signal output type environmental information detector according to the present invention uses the output of the detection end for detecting the amount of environmental information as an input signal to meet the environmental information amount along the input / output characteristics. The detecting section for generating an output signal is provided with a plurality of selectable input / output characteristics, and selecting means is provided for selecting the input / output characteristics of the detecting section in response to a predetermined output signal value of the detecting end. At the same time, since the selection status signal generating means for generating a signal indicating the selection status of the selecting means is provided, the smoke detected by referring to both signals sent from the detector when obtaining the environmental information amount at the receiving side is detected. Since the concentration can be determined and the detector itself selects the input / output characteristics that best match the input signal value and sends out the analog output signal, the receiver side manages many detectors at once. You Even in such a case, the processing becomes extremely simple.

Further, since the selecting means for selecting the input / output characteristic has the hysteresis characteristic, the operation of the whole detector becomes stable.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of an analog signal output type environment information detector according to the present invention, and FIG. 2 is an input / output characteristic curve diagram used to explain the operation of the detector of FIG. (a) shows the case where the maximum value of the input / output characteristics and the minimum value of the next input / output characteristics match, and (b) shows the maximum value of the input / output characteristics and the minimum value of the next input / output characteristics that overlap in a predetermined range. The case is shown, and (c) shows the case where the next input / output characteristic is selected with hysteresis and overlapping in a predetermined range. FIG. 3 is a circuit diagram of another embodiment of the analog signal output type environment information detector according to the present invention, FIG. 4 is an input / output characteristic curve diagram used for explaining the operation of the detector of FIG. 3, and FIG. FIG. 6 is a circuit diagram of a conventional temperature detector, and FIG. 6 is an input / output characteristic curve diagram used to explain the operation of the detector of FIG. 10 ... Platinum resistance thermometer, 31 ... Ionization chamber, 14, 18 ... Operational amplifier, 19, 35 ... Comparator, 17 ... Switch for controlling amplification gain, 15
... Switch for reference value control, 34 ... Switch, 23,39 ... Control circuit

Claims (2)

[Claims] 1. An analog signal output type environmental information detector which has a detection end for detecting the amount of environmental information such as smoke, temperature and gas, and which outputs an analog signal based on the detection signal from the detection end. A plurality of input / output characteristics are provided, and each input / output characteristic is sequentially arranged and selected so that the maximum value of a predetermined input / output characteristic and the minimum value of the next input / output characteristic overlap or coincide with each other within a predetermined range. A processing circuit that processes the detection signal from the detection end with one input / output characteristic, and selects the next input / output characteristic when the detection signal from the detection end exceeds the range of one input / output characteristic. An analog signal output type environmental information detector, comprising: a selection unit that outputs a selection signal and that generates a signal indicating a selection status. 2. An analog signal output type environmental information detector provided with a detection end for detecting the amount of environmental information such as smoke, temperature and gas, and outputting an analog signal based on the detection signal from this detection end. It has a plurality of input / output characteristics, and each input / output characteristic is sequentially arranged so that the maximum value of a predetermined input / output characteristic and the minimum value of the next input / output characteristic overlap in a predetermined range, and one selected input is selected. A processing circuit that processes a detection signal from the detection end with an output characteristic, and a selection signal that selects the next input / output characteristic with hysteresis when the detection signal from the detection end exceeds the range of one input / output characteristic And an selecting means for generating a signal indicating the selection status, and an analog signal output type environmental information detector.