JPS62148836A - Photoelectric separation type sensor - Google Patents

Abstract

PURPOSE:To use a sensor invariably at almost constant photodetection level even at optional intervals and to set the level without using any special measur ing instrument by providing a photodetector or a display device for photo detection level setting and a level adjusting means nearby the photodetector and providing the display device with a means for confirming the upper and lower limit values of the photodetection level. CONSTITUTION:Changeover switches 30 and 31 are set to contacts 301 and 311 which select a rough adjustment level range for a comparator 32 for upper- limit level detection, and a test switch 38 is closed. (the switch of the cathode of SCR 28 associated with the switch 38 is opened at the same time.) If a high level pilot lamp 36 blinks at this time, an input signal level is lowered by a variable resistor 21 for rough adjustment and if a low level pilot lamp 37 blinks, the input level is increased by the variable resistor 21, thereby turning off the pilot lamps 36 and 37 in both cases. When a fine adjustment is made after the rough adjustment, the changeover switches 30 and 31 are switched to contacts 302 and 312 which selects a fine level range and the adjustment is made by a variable resistor 22 for fine adjustment similarly to set the input signal level more accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a photoelectric separation type sensor that detects the attenuation of light due to smoke to detect fire at an early stage.

[Conventional technology]

In a dimming type smoke detector, a light emitter and a light receiver are arranged at a predetermined distance, and when smoke enters between them, the attenuation of light due to the smoke is detected to detect a fire.In general, the luminous flux of the emitter is Since a device that spreads out at an angle of several degrees is used, the level of light received during monitoring varies depending on the distance between the emitter and receiver, and it was therefore necessary to adjust the level of light received depending on the installation location.

Conventionally, these adjustments have been made by bringing a measuring device to the installation location and connecting it to a predetermined terminal of the light receiver.

[Problem that the invention seeks to solve]

Photoelectric separate type sensors are generally installed in buildings with high ceilings and good visibility, such as gymnasiums. Connecting to a light receiver and making measurements is extremely difficult and dangerous, and requires a lot of manpower.

[Means for solving problems]

This invention consists of a light emitter equipped with a light emitting part that lights up in pulses, and a light receiver located at a predetermined distance from the light emitter, and detects a decrease in light due to smoke between the emitter and receiver and issues an alarm. In a photoelectric separate type sensor that emits
The above problem is solved by providing a display for setting the received light level and a level adjustment means on or near the light receiver, and providing a means for checking the upper and lower limits of the received light level on the display. It is.

By using such a means, the light reception level can be adjusted extremely easily and accurately to a substantially constant level depending on the length of the distance between the light emitter and the light receiver.

〔Example〕

Next, one embodiment of the present invention will be described in detail with reference to the drawings shown below.

Figure 1 is a side view showing how the photoelectric separation type sensor is installed on the ceiling, etc. Figure 2 (8) is the circuit diagram of the floodlight;
Figure (B) is a circuit diagram of the light receiver, Figure 3 is a time chart for explaining the operation of the circuit in Figure 2, and Figure 4 is a side view and a back view of the light receiver 2 shown in Figure 1. show.

In FIG. 1, reference numeral 1 indicates a light projector, and reference numeral 2 indicates a light receiver, which are disposed facing each other on a ceiling surface 3 with a predetermined distance therebetween.

FIG. 2(A) is a block diagram of the projector 1, in which the output of the short pulse oscillator 11 is modulated by the long pulse extractor 12 via the electronic switch 13, and the amplifier 14 amplifies this modulated wave. , and a light emitting element 15 that is pulse-lit by the amplifier 14. The output waveform of this amplifier 14 is shown in FIG. 3(a).

FIG. 2(B) shows a circuit diagram of the light receiver 2, in which a series circuit consisting of first and second variable resistors 21, 22 and a light receiving element 23 is connected between the power supply terminals, and the Amplifier 2 is connected from the movable terminal of resistor 22 via capacitor C.
4 is connected to the output terminal of the amplifier 24 through backflow prevention diodes Dl and D2, and a first time constant circuit 25 that maintains approximately the peak value of the output voltage of the amplifier 24 for a long time;
A second time constant circuit 26 having a relatively short time constant is connected to each of them.

The output of the second time constant circuit 26 is connected to one input terminal of a comparator 27, and the other terminal of the comparator 27 is connected to a changeover switch Sl for taking out a plurality of output voltages from the first time constant circuit 25. Tail connected. The output of the comparator 27 is applied to the 5CR28 (D gate electrode), and the relay 29 for the !4 report is controlled.

The output of the first time constant circuit 25 is further input to one input terminal of level adjustment comparators 32 and 33, and the test switch 38. It is connected to a negative potential via a resistor R5.

The other input terminals of the test comparators 32 and 33 are
Each of them is selectively connected to each connection point of a plurality of voltage dividing resistors r1 to r5 via changeover switches 30 and 31, respectively.

The output terminals of the comparators 32 and 33 are connected to one input terminal of the AND game 34 and 35, and the other end is connected to the output terminal of the amplifier 24, and lamps 36 and 37 whose blinking is controlled by this output are connected. It is provided.

The operation of such a circuit configuration will be explained. Note that the optical axis adjustment of the emitter 1 and the receiver 2 at the time of installation is performed in advance using the optical axis adjustment reference hole 41.12 provided at the bottom, as shown in FIG. It is assumed that

A method of adjusting the light reception level in such an installation state will be described below.

As shown in FIG. 3(a), from the projector 1, the excavation pulse of the first oscillator 11 is blinked with a pulse modulated by the second excavator 12 with a period T (several hundred ms). ,
This modulated light is projected onto the light receiver 2.

When this modified light is incident on the light receiving element 23 of the light receiver 2, this signal is transmitted to the first and second variable resistors 21 and 22.
The signal is extracted as an alternating current signal via the capacitor C and applied to the amplifier 24. The output waveform of this amplifier 24 is shown in FIG. 3(C).

This kind of output is the first. When applied to the second time constant circuits 25, 26 through the diodes D, , and D2, the outputs of the respective time constant circuits 25, 26 have waveforms as shown in Fig. 3 (d) and (e). It is expressed as . These outputs are
h are applied to the inputs of the comparator 27, and during normal monitoring, the voltage and voltage of the short time constant circuit 26 are always higher than the voltage of the long time constant circuit 25,
There is no output generated from .

When smoke enters between the emitter and receiver, the amount of light received by the light receiving element 23 gradually decreases depending on the concentration of the smoke [Figure 3 (b), (
Based on this decrease, the waveform appearing in the short time constant circuit 26 also gradually decreases as shown in FIG. 3(e).

However, at this time, since the voltage change in the long time constant circuit 25 is extremely slow, both time constant circuits 25.2 shown in FIG.
At the point (k) where the voltages of 6 and 6 intersect, the comparator 27
An output is output from the 5CR28, and the alarm relay 29 is activated.

Next, a level adjustment method for installing the emitter/receiver 1, 2, etc. will be described below.

That is, the luminous flux from the emitter 1 is spread by a predetermined angle of 1° (several degrees), and as a result, the luminous flux from the emitter/receiver 1, 2
The amount of light received increases or decreases depending on the distance between them, and the input level to the amplifier 24 changes each time. Connect this to variable resistor 21.2
This adjustment is performed as a rough adjustment by setting the changeover switch 30.31 to 301.311, which covers the entire coarse adjustment level range, and then closing the test switch do. (At the same time, the S
Open the cathode switch of CR28. ) At this time, if the high level indicator light 36 blinks, it means that the coarse adjustment variable resistor 2
1 to lower the input signal level, and if the low level indicator light 37 blinks, the variable resistor 21 is adjusted in the direction of increasing the input signal level, and both indicator lights 36 and 37 are turned off. The long time constant circuit 25 during this adjustment forms a time constant circuit equivalent to the short time constant circuit 26 by connecting a resistor 38.

After coarse adjustment, for further fine adjustment, selector switch 30.
The input signal level can be set even more accurately by switching the input signal level 31 to contacts 302 and 312, which are in the fine adjustment level range, and making adjustments using the fine adjustment variable resistor 22 in the same manner as in the coarse adjustment. The setting width of the upper and lower limit values is almost the same as the short time constant circuit 26.
The values of the voltage dividing resistors r1 to r5 may be set in advance for each voltage so that the pulsation width of the output voltage is close to that of the output voltage.

Level adjustment variable resistor 21.22 cut-off switch 303
1. The test switch 38 and indicator light 37 are as shown in Fig. 4 (
As shown in b), the back side of the light receiver 2 may be provided so that it can be operated or viewed from the outside.

In this embodiment, an indicator light 3 is used as a level confirmation means.
6.37 is used, but it is not limited to this, and an indicating meter or a level indicator, etc. can also be used.
However, the indicator lamps 36 and 37 may be configured to blink when the level setting is completed, and the level adjusting means is not limited to the variable resistor.

〔Effect of the invention〕

As described above, in the photoelectric separated sensor of the present invention, the level of the receiver can be easily set based on changes in the distance between the emitter and the receiver using an indicator lamp, a variable resistor, etc. provided at or near the receiver. Since it can be set to a substantially constant light receiving level even at any distance between the emitter and receiver, it has the characteristics that this level setting can be performed without using a special measuring device.

[Brief explanation of drawings]

The first page shows an example of the photoelectric separation type sensor of the present invention, FIG. 1 is a diagram showing an example of its construction in a building, FIG. ) is a circuit diagram of the light receiver (B), FIG. 3 is a time chart for explaining the operation of FIG. 2, and FIG. 4 is a side view and a back view of the light receiver 2, respectively. DESCRIPTION OF SYMBOLS 1... Light emitter, 2... Light receiver, 15... Light emitting element for light emission 21, 22... Variable resistor, 23... Light receiving element, 25, 26 Time constant circuit, L, , L2 ... Indicator light patent applicant Nittan Co., Ltd. Figure 1 Figure 4 Receiver

Claims (3)

[Claims] (1) Consisting of a light emitter equipped with a light emitting part that lights up in a pulsed manner, and a light receiver located at a predetermined distance from the emitter,
In the above-mentioned photoelectric separation type sensor that detects attenuation of light due to smoke between the emitter and receiver and issues an alarm, a display for setting the received light level and level adjustment means are provided at or near the receiver. . A photoelectric separation type sensor, characterized in that the display device is provided with means for confirming an upper limit value and a lower limit value of the received light level. (2) The photoelectric separation type sensor according to claim 1, characterized in that a variable resistor is used as the level adjustment means. (3) The photoelectric separation type sensor according to claim 1, characterized in that a plurality of indicator lights are provided as means for confirming the upper limit value and lower limit value of the indicator.