JP5872418B2 - Photoelectric sensor - Google Patents

Description

  In the present invention, the light transmission unit and the light reception unit are separately arranged, and the light monitoring unit detects the change in the amount of light received due to the generation of smoke or the like by the light beam transmitted (projected) from the light transmission unit. In particular, the present invention relates to a photoelectric separation type sensor that does not require a synchronization line for connecting a light transmitting unit and a light receiving unit.

  2. Description of the Related Art Conventionally, as an example of a smoke sensor that detects smoke generated by a fire or the like, a photoelectric separation type sensor that detects smoke based on a light attenuation rate of detection light is known.

  The photoelectric separation type smoke detector is configured by arranging a light transmitting unit that transmits detection light and a light receiving unit that receives the detection light, with the monitoring region interposed therebetween, so as to face each other. Then, the detection light transmitted from the light transmission unit is received by the light receiving units arranged opposite to each other, and the light reduction amount and the light reduction rate of the received light amount of the detection light are calculated in this light reception unit. When the light attenuation rate exceeds the specified reference value, the light receiving unit determines that smoke has been generated (fire has occurred), and the fire receiver is connected to the fire receiver wired by the control line. A notification signal indicating the effect is output.

  Here, in order to appropriately determine the light reduction amount of the detection light, it is necessary to synchronize the light transmission timing of the detection light by the light transmission unit and the light reception timing of the detection light by the light reception unit. For this reason, conventionally, the light transmitting unit and the light receiving unit are connected to each other by a synchronization line (control line), and a synchronization signal is output from the light transmission unit to the light receiving unit via the synchronization line. . The light receiving unit establishes synchronization between the light transmitting unit and the light receiving unit by performing light reception at a predetermined synchronization interval with reference to the synchronization timing specified by the synchronization signal (for example, Patent Documents). 1).

Japanese Patent Laid-Open No. 08-096267

  However, in the conventional method for establishing synchronization of the photoelectric separation type sensor, since a work for laying the synchronization line which is a control line for synchronization is required, the process of attaching the photoelectric separation type sensor increases, There was a cost of laying synchronous lines. The laying cost increases as the distance between the light transmitting unit and the light receiving unit increases or as the number of light transmitting units and light receiving units is increased.

  The present invention has been made in view of such a conventional problem, and provides a photoelectric separation type sensor capable of performing mutual synchronization between a light transmitting unit and a light receiving unit without using a synchronization line. The purpose is to do.

The present invention includes a light transmitting unit that includes a light emitting element and transmits light from the light emitting element, and a light receiving unit that includes a light receiving element and receives light transmitted from the light transmitting unit, In the photoelectric separation type sensor in which the light transmitting unit and the light receiving unit are separately arranged, the light transmitting unit transmits light having the first pattern light emission and the second pattern light emission to the light receiving unit at a constant cycle. The light receiving unit includes a first amplifier connected to the first light receiving element, a second amplifier connected to the second light receiving element, a light receiving unit timer unit, and a light receiving unit control circuit. The unit timer unit activates the first amplifier after a lapse of a predetermined time, the first light receiving element receives the first pattern light emission by the activation of the first amplifier, and the first amplifier receives the first light receiving element. The second amplifier is stopped simultaneously with receiving the first pattern light emission, and the second amplifier The second light emitting element is activated at the same time as receiving one pattern light emission, the second light receiving element receives the second pattern light emission, the first pattern light emission synchronizes the light transmitting unit and the light receiving unit, and the second pattern light emission. According to the above, fire monitoring is performed .

  In the present invention, the synchronization is established by the first light receiving element receiving the first pattern light emission, and then the fire is monitored by the second light receiving element receiving the second pattern light emission. An unnecessary photoelectric separation type sensor can be obtained.

It is a block diagram of the photoelectric separation-type sensor which concerns on this invention. It is an example of the time chart of the light transmission part of the photoelectric separation-type sensor which concerns on this invention, and a light-receiving part.

Hereinafter, a photoelectric separation type sensor 100 according to an embodiment of the present invention will be described with reference to FIG.
The photoelectric separation type sensor 100 includes a light transmitting unit 1 and a light receiving unit 2, and the light transmitting unit 1 and the light receiving unit 2 are separately disposed. Here, the distance (monitoring distance) between the light transmitter 1 and the light receiver 2 is, for example, about 5 m to 100 m.

[Configuration of Light Transmitter 1]
The light transmission unit 1 includes a light transmission unit control circuit 10, a light emitting element 12, and a light transmission unit timer unit 18. In the light transmission unit control circuit 10, the light transmission unit timer unit 18 and the light emitting element 12 are connected to each other.

The light transmitter timer unit 18 measures the elapsed time and outputs a light emission timing signal notifying that it is the light emission timing of the light emitting element 12 to the light transmitter control circuit 10.
And the light transmission part control circuit 10 will output a light emission signal to the light emitting element 12, if the light emission timing signal is received, and the light emitting element 12 will light-emit.

  The light emitting element 12 emits light having the first pattern light emission p1 and the second pattern light emission p2 at a constant period. The second pattern light emission p2 is light emission for sampling for monitoring a fire. On the other hand, the first pattern light emission p1 is a light emission for synchronizing the light emission timing of the second pattern light emission p2 emitted from the light transmitting unit 1 with the light reception timing of the second light receiving element 23 of the light receiving unit 2 described later, that is, for synchronization It is luminescence.

  That is, the light emitting element 12 continues to emit light in pulses at a constant cycle according to the light transmission unit timer unit 18. In addition, the light emitting element 12 is composed of, for example, a near infrared light emitting element, and emits near infrared light having a wavelength of about 0.7 μm to 2.5 μm. Further, the light emitting element 12 does not have to transmit near infrared light, and may be any element that transmits (transmits) an electromagnetic wave having a wavelength that is attenuated by smoke.

[Configuration of the light receiving unit 2]
The light receiving unit 2 includes a light receiving unit control circuit 20, a first light receiving element 21, a first amplifier 22, a second light receiving element 23, a second amplifier 24, a peak hold circuit 25, and an A / D conversion circuit 26. And a light receiving unit timer unit 28.

  The light receiving unit control circuit 20 is connected to the first light receiving element 21 via the first amplifier 22, and is connected to the second light receiving element 23 via the A / D conversion circuit 26, the peak hold circuit 25, and the second amplifier 24. Further, it is connected to the light receiving unit timer unit 28.

  The light receiving unit timer unit 28 outputs to the light receiving unit control circuit 20 a first amplifier activation timing signal that informs that it is time to activate the first amplifier 22. When the light receiving unit control circuit 20 receives the first amplifier activation timing signal, it outputs a first amplifier activation signal to activate the first amplifier 22.

  The first light receiving element 21 is an element for receiving the first pattern emission of the light emitting element 12, and the first amplifier 22 is activated before receiving the first pattern emission so that the first pattern emission can be reliably received. doing.

  The second light emitting element 23 is an element for receiving the second pattern light emission of the light emitting element 12, so that the second amplifier 24 can receive the second pattern light emission before receiving the second pattern light emission so as to surely receive the second pattern light emission. It is running. When the first light receiving element 21 receives the first light emission pattern p1, the second amplifier 24 is activated by outputting a second amplifier activation signal from the light receiving unit control circuit 20.

The amplification factor of the first amplifier 22 is significantly lower than that of the second amplifier 24. That is, it is sufficient that the light receiving unit control circuit 20 can detect that the first light receiving element 21 has received light. Therefore, the first amplifier 22 only needs to slightly amplify the amount of light received by the first light receiving element 21. Therefore, the first amplifier 22 does not consume a large amount of power.
On the other hand, the second light receiving element 23 is a fire monitoring light receiving element, and since it is necessary to determine whether it is a fire or a non-fire according to the amount of light received, it is greatly amplified by the second amplifier 24 with high power consumption. .

[About the cycle of light emission and reception]
Hereinafter, the light emission period of the light transmitting unit 1 and the light reception period of the light receiving unit 2 that receives the light emission of the photoelectric separation type sensor 100 according to the embodiment of the present invention will be described based on the time chart of FIG. The horizontal axis indicates elapsed time, and the vertical axis indicates ON / OFF of each configuration.

  First, the light emission period of the light transmitting unit 1 is such that the first pattern light emission p1 and the second pattern light emission p2 are repeated at regular time intervals. That is, the light emitting element 12 repeats light emission at a constant cycle according to the elapsed time measurement of the light transmission unit timer unit 18.

The first pattern light emission p1 is emitted at the last timing of a period t1 to be described later. For example, the light emission is intermittently emitted four times at 50 μsec once, for example, 0.4 msec as a whole.
The second pattern light emission p2 is emitted at the last timing of a period t2, which will be described later. For example, the second pattern light emission p2 consists of one light emission at 50 μsec.

  The interval between the first pattern light emission p1 and the first pattern light emission p1, or the second pattern light emission p2 and the second pattern light emission p2 is, for example, 3104 msec. The interval from the first pattern emission p1 to the second pattern emission p2 is, for example, 4 msec. The interval from the second pattern emission p2 to the first pattern emission p1 is, for example, 3100 msec.

  In the following description, in order to simplify the explanation of the elapsed time, the pulse widths of the first pattern light emission p1 and the second pattern light emission p2 are ignored. At this time, the light emission timings of the first pattern light emission p1 and the second pattern light emission p2 are treated as the end of the pulse width for convenience.

  On the other hand, the light receiving period of the light receiving unit 2 includes a period t1, a period t2, and a period t3, which are repeated in this order.

  The period t3 is a period in which the light receiving unit timer unit 28 of the light receiving unit 2 is activated. The light receiving unit timer unit 28 is activated when the second pattern light emission p2 of the light emitting element 12 is received. Then, the light receiving unit timer unit 28 measures the time, and after a predetermined time, for example, 3 seconds elapses, the first amplifier 22 is activated and the light receiving unit timer unit 28 stops. That is, the period t3 is 3 sec, for example.

  The period t1 is a period in which the first amplifier 22 of the light receiving unit 2 is activated, and is activated until the first pattern light emission p1 is received. When the first pattern light emission p1 is received, the first amplifier 22 is stopped and the second amplifier 24 is activated. That is, the period t1 is, for example, 100 msec unless the first pattern light emission p1 is received and lost.

  The period t2 is a period in which the second amplifier 24 of the light receiving unit 2 is activated, and is activated until the second pattern light emission p2 is received. When the second pattern light emission p2 is received, the second amplifier 24 is stopped, and the light receiving unit timer unit 28 is activated. That is, the period t2 is 4 msec, for example.

  That is, the light receiving period is one period in which the periods t1 to t3 are combined. In addition, since the light reception period is based on the light emission period, 3104 msec is one period similarly to the light emission period.

  When the elapsed time measurement of the light receiving unit timer unit 28 matches the elapsed time measurement of the light transmission unit timer unit 18, the first light receiving element 21 emits the first pattern light emission p1 when 100 msec elapses after the period t1 starts. Will be received. That is, since 100 msec is provided as a spare time from the start of the period t1, even when the elapsed time measurement of the light receiving unit timer unit 28 is delayed by 100 msec compared with the elapsed time measurement of the light transmission unit timer unit 18. The first light receiving element 21 can receive the first pattern light emission p1 without any problem. Furthermore, since the period t1 continues until the first pattern light emission p1 is received, in other words, the first amplifier 22 continues to be activated until the first light receiving element 21 receives the first pattern light emission p1, so Even when the elapsed time measurement is earlier than the elapsed time measurement of the light transmission unit timer unit 18, the first light receiving element 21 can receive the first pattern light emission p1 without any problem.

  The period t2 is shorter than the period t1 because the light transmitting unit 1 and the light receiving unit 2 are synchronized in the period t1, so that the light receiving unit 1 is synchronized with the timing at which the light transmitting unit 1 emits the second pattern light emission. Since the second second amplifier 24 can be activated, the activation time of the second amplifier 24 that consumes a large amount of power can be shortened.

[Description of operation]
With reference to FIG.1 and FIG.2, the operation example of the photoelectric separation-type sensor 100 of this invention is demonstrated.
After adjusting and setting the optical axes of the light transmitting unit 1 and the light receiving unit 2, the first synchronization starts from the period t1 and continues to be activated until the first amplifier 22 receives the first pattern light emission p1. . After the first synchronization is over, normal fire monitoring begins.

  When normal fire monitoring is started, as shown in FIG. 2, the light receiving period of one period is repeated in the period t1, the period t2, and the period t3. The light transmitter 1 repeats light emission at a constant timing according to the measurement of the elapsed time of the light transmitter timer unit 18, and the light receiver 2 side adjusts the light reception timing according to the light emission. Therefore, for example, the time period t1 may be different from the time period t1 of the next cycle. Here, the operation at the time of monitoring of the photoelectric separation type sensor 100 will be described focusing on the light receiving unit 2 that adjusts the light receiving timing in order from the period t3 to the period t1 and the period t2.

  First, since the period t3 starts after the second pattern light emission p2 by the light transmitting unit 1 and does not emit light from the light transmitting unit 1, the light receiving unit control circuit 20 includes the first amplifier 22 and the second amplifier 24. Is not activated, and the light-receiving unit timer unit 28 is activated. The period t3 is, for example, 3 seconds, and the light receiving unit 2 measures the elapsed time by the light receiving unit timer unit 28.

  When the elapsed time reaches 3 seconds, that is, when the period shifts to the period t1, the first amplifier activation timing signal is output from the light receiving unit timer unit 28 to the light receiving unit control circuit 20, and the first light receiving unit control circuit 20 outputs the first time. An amplifier activation signal is output to the first amplifier 22 to activate the first amplifier 22 to prepare for the reception of the first pattern light emission p1 emitted from the light transmitter 1. That is, the first amplifier activation timing signal output from the light receiving unit timer unit 28 is triggered to activate the first amplifier 22 and shift from the period t3 to the period t1. Simultaneously with the activation of the first amplifier 22, the light-receiving unit timer unit 28 is stopped and the time measurement is reset.

Next, in the period t1, the light receiving unit 2 is in a state in which the first amplifier 22 is activated, and can receive the first pattern light emission p1 emitted from the light transmitting unit 1.
On the other hand, the light transmission unit 1 emits light according to the light transmission unit timer unit 18, and transmits a light emission timing signal notifying that it is the light emission timing of the first light emission pattern p1, for example, after 3100 msec from the second pattern light emission p2. Output to the optical unit control circuit 10. Then, the light transmission unit control circuit 10 outputs a light emission signal of the first pattern light emission p1 to the light emitting element 12, and causes the light emitting element 12 to emit the first pattern light emission p1. The timing of the first pattern light emission p1 is close after 3100 msec from the start of the period t3 in the light receiving period of the light receiving unit 2, in other words, close to 100 msec after the start of the period t1.

  At the same time when the first light receiving element 21 of the light receiving unit 2 receives the first pattern light emission p 1, the light reception output (light reception voltage) is amplified by the first amplifier 22 and input to the light receiving unit control circuit 20. The light reception output from the first light receiving element 21 serves as a trigger, and the light receiving unit control circuit 20 outputs a second amplifier activation signal to activate the second amplifier 24. At the same time, the light receiving unit control circuit 20 stops the first amplifier 22. That is, since the second amplifier 24 is activated immediately after receiving the first pattern light emission p1, in other words, the light transmitting unit 1 and the light receiving unit 2 are synchronized by receiving the first pattern light emission p1, The period t2 can be shortened.

  Finally, in the period t2, the second amplifier 24 is activated, and the second pattern light emission p2 emitted from the light transmitter 1 can be received. The second light receiving element 23 receives the second pattern light emission p2 emitted from the light transmitting unit 1 after elapse of, for example, 4 msec from the start of the period t2. The light reception output received by the second light receiving element 23 is amplified by the second amplifier 24, the peak value of the light reception output is converted into direct current by the peak hold circuit 25, and the voltage value is converted into digital data by the A / D conversion circuit 26. Then, the light receiving unit control circuit 20 calculates the light attenuation rate. In this way, fire is monitored.

  Then, at the same time that the second light receiving element 23 receives the second pattern light emission p2, the second amplifier 24 is stopped, and the light receiving unit timer unit 28 is activated to shift to the period t3.

  That is, the light transmitting unit 1 repeats two types of light emission at a constant cycle, and the light emission timing thereof is, for example, the first pattern light emission p1 is 3100 msec from the start of the period t3, and the second pattern light emission p2 is a period It is 3104 msec after the start of t3. On the other hand, when the light receiving unit 2 receives the first pattern light emission p1 in the period t1, the light receiving unit 2 synchronizes the light transmitting unit 1 and the light receiving unit 2 by activating the second amplifier 24 immediately, and uses a large amount of power. The time period t2 during which the two amplifiers 24 are activated is shortened. The light transmitting unit 1 emits light at a constant timing, while the light receiving unit 2 reduces the shift in synchronization with the light transmitting unit 1 side in the period t1, while the time shift generated after the synchronization is This is compensated by activating the first amplifier 22 or the second amplifier 24 before light is emitted from the unit 1.

  If the first light receiving element 21 cannot receive the first pattern light emission p1 during the period t1, the first amplifier 22 may be activated until the first light emission pattern p1 of the next cycle is emitted. If the first light emission pattern p1 cannot be received even after a predetermined time, an alarm may be issued because an optical axis shift or obstacle entry may be considered. Further, before issuing an alarm, the second amplifier 24 is activated for a certain period of time, for example, one cycle of the period t1 to t3, and when the second pattern light emission p2 cannot be received, an alarm such as an optical axis deviation is issued. May be issued.

  In addition, the light receiving unit timer unit 28 is not limited to the period t3 and may always be activated. In this case, the activation timing of the first amplifier 22 and the second amplifier 24 may be based on the time measurement of the light receiving unit timer unit 28, and the measurement time of the light receiving unit timer unit 28 is reset when the first pattern light emission p1 is received. As a result, it is possible to synchronize the light receiving unit timer unit 28 and the light transmitting unit timer unit 18 without time lag.

[Effect of photoelectric separation type sensor 100]
Since the photoelectric separation type sensor 100 according to the present invention synchronizes the light transmitting unit 1 and the light receiving unit 2 with the first pattern light emission p1, a control line for synchronization is provided between the light transmitting unit 1 and the light receiving unit 2. It is not necessary to lay a synchronization line.

  Further, the second amplifier 24 of the light receiving unit 2 can set a plurality of (for example, three levels) amplification factors, and the amplification factor is set at the time of construction depending on the distance between the light transmitting unit 1 and the light receiving unit 2. However, if a remote controller that emits light having a protocol for switching the amplification factor is used, the amplification factor can be switched by remote control operation without constructing a scaffold even after construction.

DESCRIPTION OF SYMBOLS 1 Light transmission part, 2 Light reception part, 10 Light transmission part control circuit, 12 Light emitting element, 18 Light transmission part timer part, 20 Light reception part control circuit, 21 1st light receiving element, 22 1st amplifier, 23 2nd light receiving element, 24 second amplifier, 25 peak hold circuit, 26 A / D conversion circuit, 28 light receiving timer unit, 100 photoelectric separation type detector, p1 first pattern light emission, p2 second pattern light emission, t1, t2, t3 period.

Claims (2)

A light transmitting unit that includes a light emitting element and transmits light from the light emitting element; and a light receiving unit that includes a light receiving element and receives light transmitted from the light transmitting unit. In the photoelectric separation type sensor that separates and arranges the light receiving unit,
The light transmitting unit transmits light having the first pattern light emission and the second pattern light emission to the light receiving unit at a constant cycle,
The light receiving unit includes a first amplifier connected to the first light receiving element, a second amplifier connected to the second light receiving element, a light receiving unit timer unit, and a light receiving unit control circuit,
The light receiving unit timer unit activates the first amplifier after a predetermined time has elapsed,
The first light receiving element receives first pattern light emission upon activation of the first amplifier,
The first amplifier stops at the same time as the first light receiving element receives the first pattern light emission ,
The second amplifier is activated simultaneously with the first light receiving element receiving the first pattern light emission , and the second light receiving element receives the second pattern light emission,
By the first pattern light emission, the light transmitting unit and the light receiving unit are synchronized,
A photoelectric separation type sensor that performs fire monitoring by the second pattern emission. The second amplifier is stopped simultaneously with the second light receiving element receiving the second pattern light emission,
The light receiving portion timer unit, photoelectric separated sensor according to claim 1, wherein said second light receiving element is activated at the same time receiving the second pattern light.