The objective of the invention is to: at the problem of above-mentioned existing optical detector of fire smoke sensitivity adjustment existence, a kind of servicing unit that need not be complicated is proposed, in pure air, directly adjust the optical detector of fire smoke sensitivity of method, thereby make the adjustment of optical detector of fire smoke both simple, enough accuracys are arranged again.Simultaneously, the present invention also will provide the optical detector of fire smoke of this method of utilization, implement thereby make method of the present invention be easy to popularize.
For the ease of understanding method of adjustment of the present invention, at first its ultimate principle is made a brief description theoretically in conjunction with Fig. 1.In any optical detector of fire smoke that Fig. 1 represents, I is the optical transmitting set working current, K
IBe the photoelectric conversion factors of optical dark room, K
ABe the amplifier gain coefficient, S is the output of detector, V
bInput misalignment rate for amplifier.Theory and practice proves that for specific optical detector of fire smoke reasonable in design, if workmanship is subjected to good control, the mathematic(al) representation of its output is:
S=I (m+m
o) K
IK
A+ V
bK
A(1) m is the interior smokescope of optical dark room in the formula, m
oBe the equivalent background smokescope.
Because optical dark room accomplishes that in structural design " complete black " is very difficult, even therefore in non smoke, be under the pure air situation, the light that optical transmitting set is sent when transmitter current I is not equal to zero, in optical dark room after repeatedly reflecting and absorbing, still can some be converted into the output signal of detector, and the above-mentioned just equivalent background smokescope m of corresponding this output signal
o
Under the pure air condition, smokescope m=0, the output of detector at this moment is background signal S
o
S
o=Im
oK
IK
A+V
bK
A……………………………………………………………………(2)
By (2) formula as seen, the background signal S of detector
oForm by two parts.
First is by optical dark room equivalent background smokescope m
oCause, with optical transmitting set working current I, optical dark room photoelectric conversion factors K
xWith the amplifier gain COEFFICIENT K
ARelevant.In modern fire detector, this part designs wittingly and is being approximately the 10-30% that detector is completely exported, and realize whereby the diagnosis of detector running status and compensation automatically, and this patent is given it and had special purposes--adjust detector sensitivity.
Second portion is by amplifier input misalignment rate V
bCause, with the amplifier gain COEFFICIENT K
ARelevant.As make optical transmitting set working current I=0, can measure this part.
Usually amplifier is imported misalignment rate V
bCan do very for a short time by selecting suitable device and appropriate design circuit.Like this, at V
bK
A" Im
oK
IK
ACondition under, (2) formula can be reduced to
S
o=Im
oK
IK
A……………………………………………………………………(3)
In detector is made, optical transmitting set working current I and amplifier gain K
ACan control quite accurately, optical dark room also can be done enough accurately, but regrettably the characteristic of optical device (optical transmitting set and optical receiver) exists the discreteness that can not be ignored, therefore the m in (1), (2), (3) formula
oK
IAll be different concerning each detector.
The essence of adjustment detector sensitivity method of the present invention is by adjusting amplifier gain K
AOr/and transmitter working current I makes detector background signal S
oReach a certain desired value scope.The ratio that this scope can be defined as the minimum and maximum value of detector output according to the regulation of national standard G B4715-1993 " spot-type smoke detector technical requirement and test method " is not more than 1.6, also can be defined as a scope of being strict in national standard, as 1.2,1.3,1.4 etc. according to the company standard of manufacturer.
Based on above theory, optical detector of fire smoke sensitivity adjustment method of the present invention can reduce following steps: A. places pure air with optical detector of fire smoke, cuts off the optical transmitting set power supply, measures the output misalignment rate of amplifier in the detector; B. switch on to optical transmitting set; C. measure detector output, so output drops on desired extent with the difference of the output misalignment rate of the rapid amplifier of previous step, then adjusts and finishes, otherwise enter next step; D. adjust amplifier gain or/and the optical transmitting set working current returns step C, continue test.Adjust amplifier gain K
AThe time, amplifier output misalignment rate also and then changes, so above-mentioned steps C, D may repeat repeatedly.
Under the amplifier misalignment rate can uncared-for situation, above-mentioned detector sensitivity method of adjustment is reduced to: A. placed pure air with optical detector of fire smoke, connected the optical transmitting set power supply; B. measure the output of detector, so output drops on desired extent, then adjusts and finishes, otherwise enter next step; C. adjust amplifier gain or/and the optical transmitting set working current returns step B and continues test.
In order to improve the accuracy that detector sensitivity is adjusted, above-mentioned adjustment can be in higher amplifier gain or/and carry out under the bigger optical transmitting set working current situation.
Because directly adjustment optical detector of fire smoke sensitivity under the pure air condition, and have enough degree of accuracy, so the present invention is simple, after applying, will help to reduce optical detector of fire smoke manufacturing cost, enhance productivity.
The basic technical scheme of optical detector of fire smoke of utilization the inventive method is: by optical transmitting set that places optical dark room and optical receiver, on the basis of the optical detector of fire smoke basic circuit that optical transmitting set feed circuit and smoke signal amplifier constitute, also set up the optical transmitting set working current circuit for regulating and controlling of forming by switch control element and resistive element, and form the amplifier gain circuit for regulating and controlling by resistor network and on-off element, wherein optical transmitting set working current circuit for regulating and controlling is connected with optical transmitting set, and the amplifier gain circuit for regulating and controlling links to each other with the amplifier gain control end.In the use,, the desired value scope is arrived in sensitivity adjustment by the independent or associated working of above-mentioned two circuit for regulating and controlling.
The derivation technical scheme of the optical detector of fire smoke of utilization the inventive method is: on above-mentioned basic scheme basis, increase control optical transmitting set working current circuit for regulating and controlling and the microprocessor of amplifier gain circuit for regulating and controlling and the memory storage of access sensitivity correction factor, memory storage wherein both can be integrated with microprocessor, also can be used as the outer member of microprocessor.So in use, as long as calculate and storage sensitivity correction factor, optical detector of fire smoke just can be finished adjustment, and be need not directly to carry out sensitivity adjustment automatically by method of the present invention under programmed control.
The invention will be further described below in conjunction with accompanying drawing.
At first the inventive method specific implementation process is described by Fig. 2.In the circuit of Fig. 2: E is optical transmitting set D
2Power supply, R
4Be current-limiting resistance, optical transmitting set D
2Working current I=E/R
4D
1Be optical receiver; Optical receiver D
1With optical transmitting set D
2All be in the optical dark room shown in the dotted line, its photoelectric conversion factors is K
IM is a smokescope, m=0 under the pure air condition; m
oBe optical dark room equivalent background smokescope; N
1Be amplifier, its gain coefficient is K
A, its input misalignment rate is V
bRP
1For potentiometer, R are adjusted in gain
1And R
2Fixed resistance, RP
1, R
1And R
2Decision amplifier N
1Gain coefficient K
IDU is a signal indicating device; S
1, S
2, S
3Be debug switch, R
3And R
5Be debugging resistance.In the above element, switch control element S
2, S
3With resistive element R
5, R
4Form optical transmitting set working current circuit for regulating and controlling 1, with optical transmitting set D
2Series connection, switch control element S
1With resistive element R
3, RP
1Form amplifier gain circuit for regulating and controlling 2, with amplifier N
1Inverting input connect.
The concrete adjustment method of optical detector of fire smoke sensitivity shown in Figure 2 can be divided following four kinds of situations:
Situation one: at normal transmission electric current and gain is debug switch S
1And S
2Under the condition that all disconnects, carry out sensitivity adjustment by following three kinds of concrete grammars.
The concrete grammar 1--of situation one adjusts sensitivity by adjusting amplifier gain, and step is: A. places pure air with optical detector of fire smoke, cuts off debug switch S
3, read-out amplifier misalignment rate output valve on DU; B. closed debug switch S
3Make the optical transmitting set energising; C. on DU, read the detector output quantity, drop on desired extent, then adjust and finish, otherwise enter next step as difference with the output misalignment rate of the rapid amplifier of previous step; D. by regulator potentiometer RP
1Adjust amplifier gain K
A, return step C.
Because regulator potentiometer RP
1Can change amplifier N
1Gain, thereby change amplifier misalignment rate V in the represented detector background signal of (2) formula
bK
A, so above-mentioned steps C, D may repeat repeatedly.
When the amplifier misalignment rate can be left in the basket, this detector sensitivity set-up procedure can be reduced to: A. placed pure air with optical detector of fire smoke, closed debug switch S
3Make the optical transmitting set energising; B. read output quantity on detector output signal indicating device DU, so output drops on desired extent, then adjusts and finishes, otherwise enter next step; C. regulator potentiometer RP
1, return step B and continue test.
The concrete grammar 2--of situation one adjusts sensitivity by adjusting the optical transmitting set electric current, and step is: A. places pure air with optical detector of fire smoke, cuts off debug switch S
3, read-out amplifier misalignment rate output valve on DU; B. closed debug switch S
3Make the optical transmitting set energising; C. on DU, read the detector output quantity, drop on desired extent, then adjust and finish, otherwise enter next step as difference with the output misalignment rate of the rapid amplifier of previous step; D. by changing optical transmitting set current-limiting resistance R
4Resistance, adjust optical transmitting set working current I, return step C.
When the amplifier misalignment rate can be left in the basket, this detector sensitivity set-up procedure can be reduced to: A. placed pure air with optical detector of fire smoke, connected debug switch S
3B. read output quantity on detector output signal indicating device DU, so output drops on desired extent, then adjusts and finishes, otherwise enter next step; C. change current-limiting resistance R
4Resistance, return step B and continue test.
The concrete grammar 3--of situation one adjusts amplifier gain simultaneously and the optical transmitting set working current is adjusted sensitivity, and step is: A. places pure air with optical detector of fire smoke, cuts off debug switch S
3, read-out amplifier misalignment rate output valve on DU; B. closed debug switch S
3Make the optical transmitting set energising; C. on DU, read the detector output quantity, drop on desired extent, then adjust and finish, otherwise enter next step as difference with the output misalignment rate of the rapid amplifier of previous step; D. by regulator potentiometer RP
1Adjust amplifier gain K
A, simultaneously by changing current-limiting resistance R
4Resistance is adjusted optical transmitting set working current I, returns step C.
Because regulator potentiometer RP
1Can change amplifier N
1Gain, thereby change amplifier misalignment rate V in the represented detector background signal of (2) formula
bK
A, so above-mentioned steps C, D may repeat repeatedly.
When the amplifier misalignment rate can be left in the basket, this detector sensitivity set-up procedure can be reduced to: A. placed pure air with optical detector of fire smoke, connected debug switch S
3B. read output quantity on detector output signal indicating device DU, so output drops on desired extent, then adjusts and finishes, otherwise enter next step; C. regulator potentiometer RP
1With change current-limiting resistance R
4Resistance is returned step B.
Situation two: in normal transmission electric current and higher gain, i.e. debug switch S
2Disconnection, S
1Carry out the adjustment of sensitivity under the closed condition, higher gain means the gain that is higher than normal gain but is lower than 5 times of normal gains.In Fig. 2, pass through closed debug switch S
1, with resistance R
3(10K Ω) is parallel to R
2(10K Ω) gets on, and amplifier is worked under 2 times of normal gain conditions, carries out sensitivity adjustment by situation one described three kinds of concrete grammars, and its operation steps is self-evident, does not give unnecessary details in addition.
Situation three: at normal gain and big transmitter current, i.e. debug switch S
1Disconnection, S
2Carry out the adjustment of sensitivity under the closed condition, big transmitter current means and is higher than the normal transmission electric current but is lower than 5 times of normal transmission electric currents.In Fig. 2, pass through closed debug switch S
2, with resistance R
2(18 Ω) is parallel to R
2(18 Ω) gets on, and makes optical transmitting set D
2Work under 2 times of running current conditions, carry out sensitivity adjustment by situation one described three kinds of concrete grammars, its operation steps is self-evident, does not give unnecessary details in addition.
Situation four: greater than 1 times but be lower than 5 times of normal transmission electric currents and gain, i.e. debug switch S
2, S
1All carry out the adjustment of sensitivity under the Bi He condition.In Fig. 2, pass through closed debug switch S
2And S
1, with resistance R
5(18 Ω) is parallel to R
4(18 Ω), resistance R
3(10K Ω) is parallel to R
2(10K Ω) gets on, and detector is worked under normal transmission electric current and 2 times of normal amplifier gain conditions at 2 times, carries out sensitivity adjustment by situation one described three kinds of concrete grammars, and its operation steps is self-evident, does not give unnecessary details in addition.
More than at big transmitter current or/and adjust sensitivity under the gain situation, help improving the measure of precision of adjusting the result.
Circuit diagram shown in Figure 3 is the optical detector of fire smoke embodiment of a utilization the inventive method.This optical detector of fire smoke comprises the optical transmitting set D that places optical dark room shown in the frame of broken lines
2With optical receiver D
1And amplifier N
1On this detector basic circuit basis, also contain by triode V
1-V
4, resistance R
4-R
7With microprocessor P
1-P
4Mouthful optical transmitting set working current circuit for regulating and controlling of forming 1. and by resistance R
3, R
8, R
9, R
10With microprocessor P
5-P
8The amplifier gain circuit for regulating and controlling 2 that mouth constitutes.
In addition, also comprise the input/output interface I/O that connects two buses and microprocessor up in the circuit of this embodiment, convert bus voltage to each functional circuit required burning voltage and each functional circuit is carried out the electric power management circuit PM of power supply management, be connected with microprocessor up, be used to store and the storer M of swap data, and the digital to analog converter A/D that detector output is converted to digital quantity.Detector links to each other with control/indicator C/D by two buses, and carries out sensitivity adjustment under its control.
Under the control of control/indicator C/D, the microprocessor up of this optical detector of fire smoke finishes following for carrying out the necessary task of sensitivity adjustment: A. passes through P
1, P
2Mouth control V
1, V
2Conducting or end, thereby control R
5, R
4Ground connection and suspension (be equivalent to the debug switch S in the control chart 2
3And S
2Connection and shutoff); B. pass through P
5Mouth controlling resistance R
3Ground connection whether (be equivalent to control debug switch S in Fig. 2
1Switch on and off); C. pass through P
6, P
7And P
8Mouthful, control R
8, R
9, R
10Ground connection whether (be equivalent in Fig. 2, adjust potentiometer RP
1); D. pass through P
3, P
4Mouthful, control V
3, V
4Conducting with end, thereby control R
6, R
7Ground connection and suspension (be equivalent to figure and in Fig. 2, change R
4Resistance); E. realize data storage and exchange.
Be not difficult to find out that above A, B, the every function of C, D can make up realization according to the described various sensitivity adjustment steps of Fig. 2, do not give unnecessary details in addition herein.
Need to prove, adjust potentiometer RP among Fig. 2
1With change R
4Resistance, and control R among Fig. 3
8, R
9, R
10And R
6, R
7Ground connection, it in carrying out the detector sensitivity adjustment unique method, for example under the situation of Fig. 3, can replace with following operation steps: the ratio that A. calculates detector output valve and desired value is the sensitivity correction factor, deposits this value in storer M; B. in the actual use of detector,, revise the real output value of detector with this sensitivity correction factor.
The optical detector of fire smoke of present embodiment can under the situation that need not other servicing units or facility, be realized the automatic adjustment of detector sensitivity according to default program, uses easy to operate.