JPS5894095A - Photoelectric smoke detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoelectric smoke detector equipped with a function determining mechanism for determining whether or not the smoke sensing function is normal.

2. Description of the Related Art Various types of rechargeable smoke detectors that perform AT detection using scattered light or transmitted light have been proposed, which are equipped with a function determination mechanism that determines whether or not the smoke detection function is normal. However, in conventional photoelectric smoke detectors, the function discrimination mechanism detects an abnormality in the smoke detection function, for example, in the scattering type, the light emitting element has stopped emitting light due to a failure. It is configured to immediately send an abnormality signal to the receiver via a dedicated signal line when it is detected that the light receiving surface is contaminated and the amount of light received by the light receiving element is reduced. For this reason, this type of conventional photoelectric smoke detector does not know when it will output an abnormal signal, so the receiver is always on! There is a problem in that a signal line is required to transmit the abnormal signal.

In view of the above points, this invention can be connected to a receiver through a pair of power and signal lines, and can determine whether or not the smoke detection function is normal by operating the receiver, and when the function is normal. The present invention provides a photoelectric smoke detector equipped with a function discrimination mechanism that sends out a normal signal (t) and an abnormal signal when an abnormality occurs.

Hereinafter, an embodiment of a scattered light type smoke detector ol equipped with a function discrimination mechanism according to the present invention will be explained with reference to the drawings.0 Figure 1 is a circuit diagram, and 1 is a circuit diagram in which a pulse signal as a synchronization signal is outputted at a predetermined period. A pulse generating circuit 2 (not shown) includes a light emitting element LH such as a light emitting diode provided in a dark box into which a chain flows, and a state circuit 21 which causes the light emitting element LH to emit light every time a pulse signal is input from the pulse generating circuit 1. The light-emitting section 3 is provided in the dark box and includes a light-receiving element 8B such as a solar cell for detecting the scattered light of the light emitted from the light-emitting element II, and an amplifier M for amplifying the output of the light-receiving element 8B. It is a light receiving section having a. 4 is a signal detection circuit that is composed of a transistor Tl + resistors R1-R4 and a capacitor CI and detects a short-pulse test start signal sent from the receiver as a calling signal and a long-pulse recovery signal; 1 and irises 2 NOT@ro N1゜Ns
A recovery circuit consisting of a resistor ILs l as and a capacitor Cs, and which outputs a clear signal tube when the signal detection circuit 4 detects a recovery signal, is reset by the clear signal of n6a, and a third This is a test circuit consisting of a NO'r circuit N1w resistors R1 to R9 and a capacitor CItC4, and a test signal output circuit 62 which is operated by a set output of a latch 61 and outputs a test signal. 7 is 111 comparator CMt, first D! ! ! ! Clip-off four-tube FF5e 4th ON'OT circuit N4 and jlI3ONOR
a fire discrimination circuit which operates when the first comparator CMI detects a test signal and outputs and holds a fire detection signal until a clear signal is input; is the second and third comparison @CHI and C
Ms, II4 and the fifth NOR circuit NR4 and NR.

and a second l1ll flip-flop FFI, and the second comparator CMI detects that the light reception output is within the normal level range, which means that the inner wall diffusely reflected light, which is noise light, increases due to the accumulation of dust in the dark box. When the third comparator CM detects that it has exceeded the upper limit value of function to output an abnormality detection signal and maintain the output state while the test circuit 6 outputs the test signal.The first pulse signal of the 4th return frequency f1 and the fire signal or abnormality are detected. The repetition frequency f! is higher than the first pulse signal which is the signal! a pulse oscillator GIC that outputs a second pulse signal, and first and second NAND circuits NAI
10 is a signal generation circuit which outputs the first pulse signal when the abnormality detection signal is not input from the function discrimination circuit 8 and outputs the j12 pulse signal when the abnormality detection signal is input. 6 NOR circuit circuit Rs +
F transistor T2 + diode D and resistor RII * R
A fire detection signal is input from the fire discrimination circuit 7, and a pair of fire signal, abnormal signal or normal signal is detected by controlling the first or second pulse signal output from the signal generation circuit 9 at 9 o'clock. 11 is a constant voltage circuit, and C is a content. ○ Figure 2 is an example of a receiver, and 12 is a fire signal that detects a fire signal or an abnormal signal with a frequency of ts. Detection circuit 13 is a normal signal detection circuit for detecting a normal signal of frequency f1, 14
15 is a recovery signal sending circuit that sends out a short-pulse call signal that is a test start signal; 15 is a recovery signal sending circuit that sends out a long I/L recovery signal; BWl is a calling switch; SWl
is a recovery switch;
2 is a contact that is closed when a signal with frequency ffi is detected, nl is a contact that is closed when the normal signal detection circuit 13 detects a signal with frequency f, 81~2m beam sea X break contact, and Ll is a contact that is closed when the normal signal detection circuit 13 detects a signal with frequency f. Fire indicator light, Lm is abnormality indicator light,
is the normal indicator light.

In this receiver, when the fire signal detection circuit 12 detects a signal of frequency f2, which is a fire warning, contacts Wz and Wz close, and the fire indicator light L1 lights up to indicate the area where the fire occurred. Also, when switch swl is closed, relay X operates and contact x
1 to x3 are closed, contact x4 is opened, and relay X is self-held. Closing this contact Jel activates the call sending circuit 14 and sends a short pulse (9) call signal to a pair of power and signal lines, and opening contact x4 prohibits the lighting of the P fire indicator light L1. be done. In this state, when the fire signal detection circuit 12 detects a signal of frequency fx, which is an abnormal signal, contacts 1 and 71/3 close, the abnormality indicator light turns on, indicating the occurrence of an abnormality, and the normal signal detection circuit' ).

When 13 detects a signal at a frequency that is a normal signal, the contact 31 closes and the normal indicator lamp Lm lights up, indicating that the sensor is functioning normally. and recovery switch S
When W1 is closed, relay Y operates, contact yt closes, recovery signal sending circuit 15 operates, and sends out a long pulse recovery signal to the pair of power and signal lines, and contact ys opens. The self-release circuit of relay To explain using FIG. 3, the terminal t"1.tm
is supplied with the power of E (b) and (l) shown in FIG. 3 (1) from the receiver through a pair of power and signal lines (not shown), , υ conduction due to i pressure drop in Fig. 3 (
Since the detection signal is not generated as shown in 2), the recovery circuit 5 does not output a clear signal as shown in FIG. 2NOB2NH43 is in the output state as shown in FIG. 3 (4) and is not set, and the test signal output circuit 62 does not output a test signal as shown in FIG. 3 (7)K when the third NOT circuit Ns is in the L output state. The pulse generating circuit 1 outputs the pulse signal shown in FIG. A pulsed current is output, and this pulsed current causes the light-emitting element LE to generate a voltage J as shown in FIG. 3 (5) in synchronization with the pulse output of the pulse generation circuit 1.
g, /<Lus emits light. The light receiving element 8B is the light emitting element LK.
The amplifier AM receives the noise light, which is internally diffusely reflected light generated on the inner wall surface of the dark box due to the light emission of A pulse is generated, and this received light output is connected to the capacitor C5=
Ctt-through jg1 ~ 1st ~ comparator CM1% CMs K
input. Since the received light output of the first and second comparators CM, CM, is less than the level Lm, Fig. 3 (8) and (9) K
As shown, in the KL output state, no fire output or abnormal output occurs, and the light reception output of the third comparator CM is at level L.

As above, when the received light output is input, it is shown in Figure 3 (10
), negative pulse motion is output and no abnormal output occurs.

Therefore, in the first DW flip-flop FFI, when the clock signal is input from the pulse generation circuit 1 to the CP terminal through the fourth NOT circuit N4, the output of the first comparator CMI input to the KD terminal is in the L state, so 2. One terminal is in the Kn output state and does not output a fire detection signal as shown in FIG. Circuit NR is the second and third comparator CMI.

Since each output of CM and ApH output is generated, one terminal is
As shown in Figure (12), it is in the Kn output state and does not output an abnormality detection signal. By the way, in the signal generation circuit 9, the pulse oscillator GE generates tIX of the frequency f1 shown in fH3 diagram (13).
Figure 3 (
14) Frequency f! The second pulse signal of
It outputs to the D circuit NA, and the first NAND circuit NA,
Since no abnormality detection signal is input from the 21st) g7 lip-flop FF, the first pulse signal is passed through and the second
The NAND circuit NAI outputs a pulse having a frequency f1 shown in pjlK3 (15) to the signal sending circuit 10 under the control of the first pulse signal and the second pulse signal. Signal sending circuit 10
3, since the fire detection signal is not input from the 6th NOR circuit NR and the IDm flip-flop FF1 (
16) As shown in K, no output is produced, so the transistor Ts is in a non-conducting state, and the power supply/signal fIAK is in the third
As shown in Figure (1) K, no pulse signal is generated. In this state where the smoke detector is functioning normally, the test switch S W t of the receiver is turned on, relay X is activated, and a call signal is generated. When the sending circuit 14 operates and sends out a short pulse calling signal shown as Pl in FIG. 3(1) to the power supply/signal -, this calling signal Pi causes the transistor T1 to
becomes non-conductive, the capacitor C1 is charged, and the signal detection circuit 4 outputs a detection signal P(' corresponding to the calling signal PIK shown in FIG. 3(2)). The charge of the 9 capacitor C, which is the L output, is discharged through the resistor R1 and the jilNOT circuit N1, but since the discharge time constant is selected to be longer than the output time of the detection signals p and I, the jllN
The detection signal p( is no longer input to the OT circuit N1, and therefore the first NOT circuit N1 becomes an H output again and the capacitor CI is recharged. As a result, the second NOT circuit N! maintains an L output and the recovery circuit 5 As shown in Fig. 3 (3), the first NOR circuit NRI outputs an L output due to the ratio detection signal Pl' which does not output a clear signal.
R, becomes the KH ratio output as shown in FIG. 3(4)K, and the latch 61 is set. The latch 61 is set and the first N
Since the OR circuit NR has an L output, the charge in the capacitor C3 is transferred to the resistor R7 and the first NOR circuit NBIi.
As a result of this discharge, the third NOT circuit Nl becomes an output and the conductor t e a is charged, and the test signal output circuit 62 outputs the test signal shown in FIG. 3 (7) K. The first comparator CMI is shown in figure jIa (8
) The KH ratio output is generated as shown in K, and when the 1st DW flip-flop FF and the Noru terminal Harita Tsuk signal are input to the CP terminal, it becomes an L output as shown in Figure 3 (11) and outputs a fire detection signal, The third NOR circuit N R
m becomes the ■ output, and the output of the fire detection signal - is held. te 2nd DII flip FF, *2NO
The 5th NOR circuit NR becomes L due to the H output of R2NH4
Since the clock signal is no longer inputted, the Q terminal retains the previous H output and does not output the abnormality detection signal as shown in Figure 3 (12).For this reason, the signal generation circuit 9 3 (15) The sixth NOR circuit NR- of the signal sending circuit 10 outputs a pulse with a frequency fl indicated by K, and the sixth NOR circuit NR- of the signal sending circuit 10
! 17 A fire detection signal is input from the lip-flop FF, and the frequency f! This pulse causes the transistor T to conduct, and the circuit ILlk f shown in Fig. 313 (1) to be connected to the power supply and signal line.
The pulse signal at t is sent out as a normal signal. When the normal signal detection circuit 13 of the receiver detects this normal signal, the contact %l closes and the normal indicator light lights up, indicating that the sensing function is normal.

In such a state, when the receiver's recovery switch SWl is turned on, relay Y operates, and break contact y! is opened and the normal indicator light L3 is turned off, and the make contact y1 is closed and the recovery signal sending circuit 15 is activated, and the power supply/signal line is connected to the power supply/signal line (Fig. 3 α) KP! Outputs a long-pulse recovery signal shown by . In response to this recovery signal P, the transistor T1 of the signal detection circuit 4 becomes non-conductive and outputs the detection signal P' as shown in FIG. 3(2). This detection signal p! Due to I, the recovery circuit 5 is happy, and the N0T circuit N1 becomes an L output, and the capacitor C! is discharged, and the second NOT circuit N
, becomes an H output and outputs a clear signal shown in FIG. 3 (3). The silatch 61 is reset by this clear signal, and the first NOR circuit NRI outputs an H signal from the second NOR circuit N.
R, is an L output as shown in Figure (4),'j
Capacitor Cs by H circuit of IIINOR circuit NRI
is charged, the third NOT circuit N becomes an L output, the test signal sending circuit 62 stops outputting the test signal as shown in FIG. The L output is shown in . 1st D due to clear signal! The Q terminal of flip-flop FF1 becomes H output as shown in FIG.
As shown in Figure (16), the output of the pulse signal is stopped and the transistor T! becomes non-conductive, and the signal sending circuit 10
The normal signal transmission is stopped as shown in FIG. 3(1)K. The Q terminal of the second Dal slip 70-tube FF becomes an L output due to the clear signal as shown in Figure 3 (12) K, and the reset of the latch 61 causes the 5th NOR circuit NR
When a clock signal is input through @, the 4th NO at that time
Since the B circuit NR4 has a ■ output, the Q terminal becomes a Kl output as shown in the jllIB diagram (12)K.

By the way, when Ka[ flows into the dark box due to a fire, the light receiving element 8B receives strong scattered light due to smoke every time the light emitting element 11 emits light, and the amplifier AM receives light output exceeding the fire level Ls shown in FIG. 3 (6). and (9)
A positive pulse is output as shown by K. This 111 comparator C
1st D by MI positive pulse! Flip Frog JF
s, the Q terminal becomes the KL output as shown in Figure 3 (11) and outputs a fire detection signal, and this Q terminal OL
The output is held by the third NOR circuit NBsK of
Due to the positive pulse of the second comparator CMfi, the Q terminal of the second D-type flip 70-tube FFI becomes an L output as shown in FIG. 1s3 (12), and outputs an abnormality detection signal. In response to this abnormality detection signal, the signal generation circuit 9 outputs a pulse with a frequency f2 shown in FIG. A fire signal of frequency f2 shown in Figure (1) is sent out. When the fire signal detection circuit 13 of the receiver detects a fire signal, the contact W I +! l, QJ' @ closes, and the fire indicator light L! closes as contact rl closes! lights up to indicate the occurrence of a fire.

Next, a case where an abnormality occurs in the sensing function, and a case where the light emitting element LH breaks down and stops emitting light, will be described with reference to tl & 4 diagrams.

When the light emitting element LE fails and ceases to emit light as shown in Figure 4 (5), the light receiving element SB ceases to generate a pulse output and the amplification sAM ceases to generate a light reception output as shown in Figure 4 (6). Therefore, the third comparator CM3 does not output a negative pulse as shown in FIG. 3 (10) when the pulse generating circuit 1 outputs the pulse signal shown by the dotted line in FIG. 4 (5). 2D! 17 Lip 70 Tsug FFI outputs pulses of Q terminal number f: to the signal sending circuit 10.However, since the signal sending circuit 10 does not receive the fire detection signal, the fourth
As shown in Figure (1) K, no pulse signal is sent.

In such a state, when the signal detection circuit 4 detects the calling signal P1 shown in FIG. 4 (1) K sent from the receiver and outputs the detection signal P1' shown in FIG. 4 (2) K, this detection The signal P1')C and the p latch 61 are shown in Fig. 4 (4).
Set as shown. By setting the latch 610, the test signal output circuit 62 outputs the test signal shown in FIG. 4 (7), and the first comparator CM outputs the H output shown in FIG. 4 (8). When the clock signal is input to the first Dffi flip-flop FF1, the Q terminal becomes the L output shown in FIG. 4 (11) and outputs a fire detection signal, and this fire detection signal is output and held by the third NOR circuit NR. . Also, the latch 61 is set, K, 2nd D! l
When the clock signal is no longer input, the flip-flop FF outputs and holds the previous abnormality detection signal as shown in FIG. 4 (12), and the signal generating circuit 9 changes the frequency ft as shown in FIG. 4 (15) K. continues to output pulses. In the signal sending circuit 10, in response to the fire detection signal and the pulse from the signal generating circuit 9, the sixth NOR circuit NRs outputs a pulse with a frequency f2 shown in FIG. is controlled to be conductive to the power supply/signal line as shown in Figure 4 (1).
), the fire signal detecting circuit 12 detects this fire signal, and the fire signal detecting circuit 12 detects the fire signal and contacts w1.
and V3 are closed, and the abnormality indicator light turns on due to the closure of contact point 3.
lights up to indicate a sensor malfunction.

When the receiver transmits the restoration signal P1 shown in FIG. 4 (1) and the signal output circuit jli4 outputs the detection signal P2' shown in FIG. A clear signal indicating K is output. This clear signal causes the shutter 61 to be reset as shown in FIG. 4(4)K, and the test signal output circuit 62 to stop outputting the test signal as shown in FIG. 4(7). The CMI is shown in Figure 4 (8
)K shows L output. Also, the 1st DIM flip 70 knob FF is cleared by the clear signal and JI4
As shown in FIG. 4(11), the output of the fire detection signal is stopped, and the signal sending circuit 10 stops sending out the fire signal as shown in FIG. 4(1). Furthermore, the second D flip-flop FFI is also cleared by the clear signal, but the third
Since the comparator CM is in the KH output state as shown in Figure 4 (10), the Q terminal maintains the L output and continues to output the abnormality detection signal as shown in Figure 4 (12), and the signal is generated. As shown in Fig. 4 (15), the circuit 9 continues to output pulses of frequency fl. Also, as dust accumulates inside the dark box, internally diffused reflected light increases, and the received light output drops to the upper limit of the normal level. If it exceeds the level, the second comparator CMI generates a KH output every time the received light output is input, and this H output causes the jlE2Dm7 lip 70 block F
F! The operation is the same as above except that it outputs an abnormality detection signal.

By the way, when a failure occurs in the circuit of this sensor, for example, when the first comparator CM of the fire discrimination circuit 7 fails and only the L output is generated regardless of the input signal state k, the test cannot be started. Even if the test signal output circuit 62 outputs a test signal due to the signal, the first D! 1 flip-flop FFl is ζ
The fire detection signal is output while the terminal remains in the H output state, and the house No. 1 sending circuit 10 sends neither a normal signal nor an abnormal signal to the power supply/signal line. Therefore, a failure in the sensor circuit can be determined by transmitting a test start signal on the receiver side and confirming that neither the normal indicator lamp nor the abnormal indicator lamp lights up, regardless of whether the receiver side is in use. In this case, the receiver has a second
As shown by the dotted line in the figure, a timer T that starts operating when a test start signal is sent is provided, and a make contact t of the timer T and break contacts Ws of the fire signal detection circuit 12 and the normal signal detection circuit 13.

If rLs and a failure indicator light L4 are provided, failure can be indicated.・To explain one embodiment of a transmitted light type smoke detector using Figure 5, JI
Figure S is a circuit diagram showing only the parts that are different from the scattered light type smoke detector in Figure 1, in which the light receiving element 8B is provided at a position to receive the transmitted light from the light emitting element I, and the all comparators CM and Just as the transmitted light is reduced by smoke and the received light output reaches the fire level, H output, which is the fire output, is generated. In order to generate R output, which is an abnormal output, when the output exceeds the upper limit of the normal level, the rattan 3 comparator CMs will reduce the transmitted light due to contamination of the emitting and receiving surfaces, and the received light output will be at the normal level. The configuration is such that five outputs, which are abnormal outputs, are generated when the lower limit of . , N0TIial path N of Takita test signal output circuit axKags.

A transistor T4 whose conduction is controlled by the output of this NOT circuit is provided, and the reference signal of the 11 & 1 comparator CM11 is normally determined by the division ratio of the resistors R3 and R11, and by the division ratio of the resistors RIO, R13, and R2H during testing. The other circuit configurations are the same as in FIG. 1. In the transmitted light smoke detector configured in this way, when the light reception output decreases to the fire level due to fire smoke, the first comparator CM becomes an H output, and the first Dfi flip-flop FF outputs a fire detection signal. At the same time, the third comparator CM also becomes an H output, and the second DIl flip-flop FF outputs an abnormality detection signal, and the received light output increases above the upper limit of the normal level due to the influence of external light noise, and the second comparison is performed. If the device eM1 outputs H, or the light receiving output decreases below the lower limit of the normal level due to contamination of the emitter/receiver surface, and the third comparator CM3 outputs H, the second D-type flip-prop FF becomes abnormal. When a test start signal is input from the main receiver that outputs the detection signal, the test signal output circuit 62 operates and the fifth NOT circuit block becomes an L output, and this L output causes the transistor T4 to become non-conducting, resulting in the first comparison. CM
When the reference potential of I rises and the light reception output is input, the first comparator CM1 produces an H output, and the circuits other than those described above operate in the same way as a scattered light type smoke detector. Note that if the influence of external light noise is not taken into consideration, the second comparator CMst is omitted;
4th NOR circuit NR.

The output of the third comparator CMs may be connected to one of the inputs.

Incidentally, in each of the above embodiments, the case where the function discrimination circuit 8 outputs and holds a signal indicating the functional state immediately before the test is started will be explained. Lipflop FF,
When the 4-way signal is input to the ocp terminal through the fourth NOT circuit N4, even if the functional status changes from normal to abnormal or vice versa during the test, it is possible to notify the receiver of the change. A pulse generator circuit 1 and a pulse oscillator G E t are provided.Instead, one pulse oscillator and a divider that divides the pulse output of this oscillator are provided, and the first signal, second signal, and synchronization signal are output from this divider. You can also get it. In addition, when a large number of sensors are connected to a pair of power and signal lines, the signal sending circuit 10 shown in FIG.
As shown by the dotted line, a modulation oscillator GE is installed so that its modulation frequency is J%-& for each sensor on the same line, and the output of this oscillator GE1 is used to transmit the q signal [gI
ji! When the pulse signal sent from the sensor 10 is suppressed, the sensor that sent the signal can be identified by discriminating the modulation frequency of the pulse signal on the receiver side.

According to this invention, when a smoke detection function is operated by remote control from a receiver during a function test, a normal signal can be sent to the receiver if the smoke detection function is normal, and an abnormal signal can be sent to the receiver if an abnormality is occurring. Since it connects to the receiver with a pair of power and signal lines without requiring a dedicated signal line for signals, it is possible to determine whether there is an abnormality in the circuit on the receiver side when testing the smoke detection function. An optical smoke detector equipped with a function discrimination mechanism can be obtained.

and others

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an embodiment of a rechargeable smoke detector according to the present invention, Figure 2 is a circuit diagram of an embodiment of a receiver, and Figures 3 and 4 are the photoelectric smoke detector of Figure j11. FIG. 5 is a circuit diagram of a main part of another embodiment of the photoelectric smoke detector according to the present invention. L E-...Light emitting element, TODO...Light receiving element, 5...Recovery circuit, 6...Test circuit, 61...Latch, 62...
...Test signal output circuit, 7...Fire discrimination circuit, 8...
・Function discrimination circuit, 9...Signal generation circuit, 10...Signal sending circuit, FFl-...DLL flip-flop of fire discrimination circuit 7, FFI...DI of function discrimination circuit 8! CMI--detection circuit of the fire discrimination circuit 7, CMs, CM,-detection circuit of the function discrimination circuit 8. Patent applicant Jinnomi Disaster Prevention Industry Co., Ltd. Figure 2 Figure 3 (16): Figure 4 (5)
,,4 knees (B)” '
-m-,-shiku16) L---,--

Claims (1)

[Claims] 1. Change in scattered light or transmitted light due to smoke particles of light emitted from a light emitting element connected by a pair of power supply and signal lines to a receiver having the function of sending out a test start signal and a restoration signal. A photoelectric smoke detector of the scattered light type or transmitted light type that detects the smoke with a light-receiving element, and operates when it detects a test start signal sent from the receiver from the pair of power and signal lines. A test circuit that maintains the output of the signal until a signal is input, and a fire detection circuit that operates and outputs a fire detection signal when the light receiving output of the light receiving element reaches the fire level or a test signal is input from the test circuit. Discrimination diagram-, a function discrimination circuit that outputs an abnormality detection signal when the output of the light receiving element deviates from the normal level range, and a 10th signal 1 when the above function discrimination circuit does not output an abnormality detection signal. a signal generating circuit that outputs a second signal different from the first signal when the detection signal is being output; and a first signal generating circuit that outputs a second signal different from the first signal when the fire detection circuit is outputting the fire detection signal; or a signal exit circuit that sends a second signal to the pair of power supply/signal lines, and a restoration circuit that outputs the clear signal when it detects a recovery signal sent from the receiver from the pair of power supply/signal lines. A photoelectric smoke detector comprising a circuit. and a test signal output circuit which is operated by the set output of the latch and outputs a test signal -1tt, according to claim 1. The test circuit consists of a latch that is set by a test start signal and reset by a clear signal from a recovery circuit, and a test signal output circuit that operates according to the set output of the latch and outputs a test signal. The discrimination circuit generates a detection output when the received light output deviates from the normal level range, and includes a Dll flip-flop that outputs a fault detection signal based on the detection output, and a DLL flip-flop that outputs a fault detection signal when the received light output deviates from the normal level range, while the latch generates a set output. Above D'! A photoelectric smoke detector according to claim 1, comprising a circuit for inhibiting a change in the output of a Ji flip-flop. 4. When the fire detection circuit detects that the received light output is different from the fire level, ta is a detection circuit that generates a detection output when a test signal is input, and p outputs a fire detection signal from the detection output D!
17 lip flop and the above D! Claim 1 comprising a circuit that holds the fire detection signal output of the i[7 lip-flop until the recovery path outputs a clear signal.
Photoelectric smoke detector as described in section. 5. Claims in which the function discrimination circuit comprises a detection circuit that generates a detection output when the received light output deviates from a normal level range, and a Dffiff flip-flop that outputs an abnormality detection signal based on the detection output! Photoelectric smoke detector described in #1 @.