CN102589614A - Digital temperature and humidity detection device - Google Patents
Digital temperature and humidity detection device Download PDFInfo
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- CN102589614A CN102589614A CN2012100228911A CN201210022891A CN102589614A CN 102589614 A CN102589614 A CN 102589614A CN 2012100228911 A CN2012100228911 A CN 2012100228911A CN 201210022891 A CN201210022891 A CN 201210022891A CN 102589614 A CN102589614 A CN 102589614A
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Abstract
The invention relates to a digital temperature and humidity detection device. The digital temperature and humidity detection device structurally consists of a temperature induction circuit A, a humidity induction circuit B, a two-way eight-position dial-up switching circuit C, an analog/digital (A/D) conversion circuit D, a reset circuit E, a central processor unit F, a crystal oscillator circuit G, a digital/analog (D/A) conversion circuit I, a loosening device and voltage/current protective circuit H and a temperature and humidity analog quantity output circuit J, wherein the temperature induction circuit A, the humidity induction circuit B, the A/D conversion circuit D, the central processor unit F, the D/A conversion circuit I, the loosening device and voltage/current protective circuit H, and the temperature and humidity analog quantity output circuit J form a main circuit; the two-way eight-position dial-up switching circuit C provides temperature and humidity compensation data during calibration of a temperature and humidity sensor; and the reset circuit E, the crystal oscillator circuit G and the central processor unit F are connected to provide necessary support for the work.
Description
Technical field:
The present invention relates to a kind of temperature humidity detecting instrument, specifically a kind of digital humiture pick-up unit.
Background technology:
The measurement of temperature and humidity and control are one of important process targets of many industries; No matter be grain depot, Chinese crude drug warehouse, or books are preserved fields such as the production installation of meteorological observation, scientific research and specialities; All need the temperature and humidity of regulation; And along with the fast development of China industry, need present the trend of quick growth to the occasion of Temperature and Humidity Control, yet temperature and humidity but is the index of the most difficult guarantee; To this situation, development is reliable, practical, high-precision temperature and humidity detection system just seems extremely important.Though the Temperature Humidity Sensor kind of prior art is a lot; But it is very unreasonable that in use ubiquitous deficiency is a circuit design; The output accuracy that is mainly reflected in traditional Temperature Humidity Sensor mainly leans on calibrations such as potentiometer, adjustable resistance; After working long hours, fluctuation can appear in the resistance of potentiometer, adjustable resistance etc., causes the output accuracy of humiture value to engender that deviation strengthens phenomenon; Therefore measuring accuracy is difficult to guarantee, and often unsatisfactory at aspects such as the linearity, repeatability, interchangeability, consistance.And the protection that lacks voltage and current overload, thereby exist the result of use of Temperature Humidity Sensor and bigger influence is arranged serviceable life.
Summary of the invention:
The object of the invention mainly is to overcome the shortage of traditional Temperature Humidity Sensor in above design, provides a kind of circuit design more reasonable, high precision output, protect more perfect, the Temperature Humidity Sensor of longer service life.
Technical scheme of the present invention realizes by following mode; Its structure is made up of temperature sense circuit A, humidity inductive circuit B, eight toggle switch circuit of two-way C, A/D change-over circuit D, reset circuit E, central processor unit F, crystal oscillating circuit G, D/A change-over circuit I, fluff device and electric current and voltage holding circuit H and temperature and humidity analogue quantity output circuit J; Wherein temperature sense circuit A, humidity inductive circuit B, A/D change-over circuit D, central processor unit F, D/A change-over circuit I, fluff device and electric current and voltage holding circuit H, temperature and humidity analogue quantity output circuit J form main circuit; Eight toggle switch circuit of two-way C provides the temperature and humidity offset data when Temperature Humidity Sensor is calibrated; The beautiful single-chip microcomputer processing unit of reset circuit E, crystal oscillating circuit G F is connected to its work provides necessary support, wherein:
Temperature sense circuit A is made up of integrated circuit U4, resistance R 9-R14, capacitor C 4, C5, C15, and wherein resistance R 11 is a RTD, i.e. the temperature sense probe; Between 7 pin and power supply 4.2V of resistance R 9 and R12 series connection integrated circuit U4, between resistance R 11 1 ends economize on electricity resistance R9, the R12, other end ground connection; Resistance R 10 and R13 are series at power supply 4.2V and connect between 8 pin of integrated circuit U4, between resistance R 14 1 terminating resistor R10, the R13, and other end ground connection; Capacitor C 15 also connects 7,8 pin of integrated circuit U4; Capacitor C 5 connects between 7 pin and ground wire of integrated circuit U4, and capacitor C 4 also connects between 8 pin and ground wire of integrated circuit U4, wherein capacitor C 4, C5 ground connection;
Humidity inductive circuit B is made up of integrated circuit U2, resistance R 1-R8, capacitor C 1-C3, and wherein C1 is a humicap, i.e. humidity inductive probe, and resistance R 4 also connects 1,12 pin of U2; Resistance R 2 also connects 1,6 pin of U2, and resistance R 3 also connects 6,12 pin of U2, and resistance R 1 also connects 1,7 pin of U2; Resistance R 7 also connects 6,3 pin of U2, and resistance R 8 also connects 3,10 pin of U2, and capacitor C 1 also connects 7,3 pin of U2; Capacitor C 2, C3 also connect 3,12 pin of U2, the 3 pin ground connection of U2, and 12 pin meet power supply 5V;
Eight toggle switch circuit of two-way C is made up of toggle switch SW8-1 and SW8-2, exclusion PS9-1 and PS9-2; The 1-8 pin of toggle switch SW8-1 links to each other with the 2-9 pin of exclusion PS9-1 respectively; The 9-16 pin ground connection of toggle switch SW8-1,1 pin of exclusion PS9-1 connects the 5V power supply, and the 1-8 pin of toggle switch SW8-2 links to each other with the 2-9 pin of exclusion PS9-2 respectively; The 9-16 pin ground connection of toggle switch SW8-2,1 pin of exclusion PS9-2 connects the 5V power supply;
A/D change-over circuit D is made up of integrated circuit U4, crystal oscillator XT2, capacitor C 6 and C7; 5 pin of integrated circuit U4,9 pin, 15 pin connect 3V, 1.2V, 3V power supply respectively; The two ends of crystal oscillator XT2 connect 2 pin and 3 pin of integrated circuit U4 respectively; Capacitor C 6, C7 connect ground connection behind the two ends of crystal oscillator XT2 respectively, and 1 pin of integrated circuit U4,12 pin, 13 pin connect 7 pin, 12 pin, 13 pin of integrated circuit U1 respectively; The 16 pin ground connection of integrated circuit U4;
Reset circuit E is made up of capacitor C 8 and resistance R 15, and resistance R 15 connects between 10 pin and ground wire of integrated circuit U1, a termination 5V of capacitor C 8,10 pin of the other end integrated circuit U1 of capacitor C 8;
Central processor unit F is made up of integrated circuit U1, and 44 pin of integrated circuit U1 connect the 5V power supply, the 22 pin ground connection of integrated circuit U1;
Crystal oscillating circuit G is made up of crystal oscillator XT1, capacitor C 13, C14, and the two ends of crystal oscillator XT1 connect 20,21 pin of integrated circuit U1 respectively, and capacitor C 13, C14 connect ground connection behind the two ends of crystal oscillator XT1 respectively;
D/A change-over circuit I is made up of integrated circuit U3 and capacitor C 9; The 7 pin connecting resistance R16 of integrated circuit U3; 6 pin are connected 2.1V, 5V power supply respectively with 8 pin, the 5 pin ground connection of U3, and 1 pin of U3,2 pin, 3 pin connect 15 pin, 16 pin, 17 pin of integrated circuit U1 respectively; 4 pin connecting resistance R17, capacitor C 9 also connects 5,8 pin of integrated circuit U3;
Transmitter and electric current and voltage holding circuit H be by resistance R 16-R24, capacitor C 10, C11, diode D1, D2, D5; Triode Q1 and Q2, diode D1-D4, fuse F1-F3; Integrated circuit U5A, U5B and plug connector J1 form, and the two ends of resistance R 16 connect 7 pin of integrated circuit U3 respectively, 3 pin of U5A; Capacitor C 10 also connects 3,11 pin of U5A, the 11 pin ground connection of U5A, and 4 pin connect the 10V power supply; Resistance R 18, diode D5, fuse F1 and capacitor C 12 are serially connected between 1 pin of 4 pin and plug connector J1 of U5A, and the 1 pin crosstalk resistance R19 of U5A connects the base stage of triode Q1, and the 2 pin crosstalks resistance R20 of U5A connects the emitter of triode Q1; Diode D1 also connects between the base stage and emitter of triode Q1; The emitter of triode Q1 is crosstalk resistance R21 ground connection also, and the collector series connection fuse F3 of triode Q1 patches 1 pin of fitting J1, and 1,2 pin of diode D3 and capacitor C 12 and plug connector also connect; The 4 pin crosstalks resistance R17 of integrated circuit U3 connects 5 pin and the ground connection of integrated circuit U5B, and the 7 pin crosstalks resistance R22 of U5B connects the base stage of triode Q2, and the 6 pin crosstalks resistance R23 of U5B connects triode! 2 emitter, the emitter of triode Q2 be crosstalk resistance R24 ground connection also, and base stage and the emitter of diode D2 and triode Q2 also connects, and the collector crosstalk of triode Q2 hinders 3 pin that fuse patches fitting, and diode D4 and capacitor C 13 also patch 2/3 pin of fitting J1;
Temperature and humidity analogue quantity output circuit J is made up of connector J1, and 1 pin is public ground, and 2 pin are the output of humidity analog quantity, and 3 pin are the output of temperature simulation amount.
Advantage of the present invention is: the arithmetic element that adopts central processing unit to replace the conventional analogue circuit to constitute; Data validation and multiple automatic compensation function have been realized; Realized the high-acruracy survey of humiture value; Solved the problem that traditional Temperature Humidity Sensor exists at aspects such as stability, reliability, measuring accuracy, the perfect simultaneously protective capability of Temperature Humidity Sensor under the over-voltage and over-current situation.
The invention belongs to the temperature and humidity measurement field, be used for the temperature and humidity of all kinds of air ambients such as indoor, outdoor, air channel is carried out high-acruracy survey, according to survey report, temperature error＜± 0.2 ℃, humidity error＜± 1%.
Description of drawings:
Fig. 1 is the schematic block circuit diagram of warm and humid sensor;
Fig. 2 is the circuit theory diagrams of warm and humid sensor.
Embodiment:
Below in conjunction with accompanying drawing temperature and humidity sensing apparatus of the present invention is done following the detailed description.
Like accompanying drawing 1, shown in 2; Warm and humid sensor of the present invention is made up of temperature sense circuit A, humidity inductive circuit B, eight toggle switch circuit of two-way C, A/D change-over circuit D, reset circuit E, central processor unit F, crystal oscillating circuit G, D/A change-over circuit I, fluff device and electric current and voltage holding circuit H and temperature and humidity analogue quantity output circuit J; Wherein temperature sense circuit A, humidity inductive circuit B, A/D change-over circuit D, central processor unit F, D/A change-over circuit I, fluff device and electric current and voltage holding circuit H, temperature and humidity analogue quantity output circuit J form main circuit; Eight toggle switch circuit of two-way C provides the temperature and humidity offset data when Temperature Humidity Sensor is calibrated, the beautiful single-chip microcomputer processing unit of reset circuit E, crystal oscillating circuit G F is connected to its work provides necessary support.
Temperature sense circuit A is made up of integrated circuit U4, resistance R 9-R14, capacitor C 4, C5, C15, and wherein resistance R 11 is a RTD, i.e. the temperature sense probe; Resistance R 9 connects 7 pin like U4 after connecting with R12; After connecting with R13, the parallelly connected ground connection of resistance R 11 and R9, resistance R 10 connects 8 pin of integrated circuit U4, resistance R 10 and the parallelly connected ground connection of R14; Capacitor C 4, C5, C15 filtering, wherein capacitor C 4, C5 ground connection.
Humidity inductive circuit B is made up of integrated circuit U2, resistance R 1-R8, capacitor C 1-C3, and wherein C1 is a humicap, and promptly humidity inductive is popped one's head in, and resistance R 6 connects 13 pin of U2; Resistance R 5 and R8 series connection, R8 ground connection, 12 pin of a termination U2 of resistance R 5, resistance R 4 connects 1 pin of U2; Resistance R 3, R7 series connection, 6 pin of resistance R 3 one termination U2, resistance R 7 ground connection; Resistance R 1, R2 also connect 1 pin of U2,6 pin of another termination U2 of resistance R 2 wherein, resistance R 1 and humicap C1 series connection; 7 pin of another termination U2 of resistance R 1, humicap series connection C1 ground connection, ground connection after capacitor C 2, the C3 filtering.
Eight toggle switch circuit of two-way C is made up of toggle switch SW8-1 and SW8-2, exclusion PS9-1 and PS9-2; The 1-8 pin of toggle switch SW8-1 links to each other with the 2-9 pin of exclusion PS9-1 respectively; The 9-16 pin ground connection of toggle switch SW8-1,1 pin of exclusion PS9-1 connects the 5V power supply, and the 1-8 pin of toggle switch SW8-2 links to each other with the 2-9 pin of exclusion PS9-2 respectively; The 9-16 pin ground connection of toggle switch SW8-2,1 pin of exclusion PS9-2 connects the 5V power supply.
A/D change-over circuit D is made up of integrated circuit U4, crystal oscillator XT2, capacitor C 6 and C7; 5 pin of integrated circuit U4,9 pin, 15 pin insert 3V, 1.2V, 3V power supply respectively; The two ends of crystal oscillator XT2 connect 2 pin and 3 pin of integrated circuit U4 respectively; Capacitor C 6, C7 connect ground connection behind the two ends of crystal oscillator XT2 respectively, and 1 pin of integrated circuit U4,12 pin, 13 pin connect 7 pin, 12 pin, 13 pin of integrated circuit U1 respectively.
Reset circuit E is made up of capacitor C 8 and resistance R 15, capacitor C 8 and resistance R 15 series connection, a termination 5V electric capacity of electric capacity, 10 pin of other end integrated circuit U1, capacitor C 8 ground connection.
Central processor unit F is made up of integrated circuit U1, and 44 pin of integrated circuit U1 connect the 5V power supply, the 22 pin ground connection of integrated circuit U1.
Crystal oscillating circuit G is made up of crystal oscillator XT1, capacitor C 13, C14, and the two ends of crystal oscillator XT1 connect 20 pin and 21 pin of integrated circuit U1 respectively, and capacitor C 13, C14 connect ground connection behind the two ends of crystal oscillator XT1 respectively.
D/A change-over circuit I is made up of integrated circuit U3 and capacitor C 9; The 7 pin connecting resistance R16 of integrated circuit U3; 6 pin of integrated circuit U3 are connected voltage 2.1V, 5V respectively with 8 pin; The 5 pin ground connection of integrated circuit U3,1 pin of integrated circuit U3,2 pin, 3 pin connect 15 pin, 16 pin, 17 pin of integrated circuit U1 respectively, the 4 pin connecting resistance R17 of integrated circuit U3.1 pin of one termination integrated circuit U3 of capacitor C 9, other end ground connection.
Transmitter and electric current and voltage holding circuit H are made up of resistance R 16-R24, capacitor C 10, C11, diode D1, D2, D5, triode Q1 and Q2, TVS overvoltage protection pipe D3 and D4, resettable fuse F1 and F2, integrated circuit U5A and U5B, and resistance R 16 is connected 3 pin of integrated circuit U5A, the other end ground connection of capacitor C 10 with capacitor C 10; Resistance R 20 1 ends connect 2 pin of integrated circuit U5A, and the other end connects diode D1, an end of triode Q1 and resistance R 21; Resistance R 21 ground connection, diode D1 connects R19 and triode Q1, and R19 connects 1 pin of integrated circuit U5A; The end of triode Q1 connects resettable fuse F3, and double insurance silk F3 connects 1 pin that is connected connector J1 behind D3 and the C12,4 pin of integrated circuit U5A and 11 pin connect power supply 10V and; Resistance R 17 is connected 5 pin of integrated circuit U5B with capacitor C 11, the other end ground connection of capacitor C 11, and resistance R 23 1 ends connect 6 pin of integrated circuit U5B; The other end connects diode D2; One end of triode Q2 and resistance R 24, resistance R 24 ground connection, diode D2 connects R22 and triode Q2; R22 connects 7 pin of integrated circuit U5A; The end of triode Q2 connects resettable fuse F2, and double insurance silk F2 connects 3 pin that are connected connector J1 behind D4 and the C13,4 pin of resistance R 18 1 termination integrated circuit U5A; Another terminating diode D5 and resettable fuse F1, resettable fuse F1 connects 2 pin of TVS overvoltage protection pipe D3 and D4, resettable fuse F1 and F2 and connector J1.
Temperature and humidity analogue quantity output circuit J is made up of connector J1, and 1 pin is public ground, and 2 pin are the output of humidity analog quantity, and 3 pin are the output of temperature simulation amount.
Embodiment
Humiture collecting method of the present invention is following:
Temperature Humidity Sensor be with central processing unit be integrated circuit U1 be core one the cover detection system, based on high sensitivity and the controllability of central processing unit to digital signal.According to the situation of change of the temperature in the field monitoring scope, humidity, the real-time humiture induction module that passes through carries out the collection of signal and converts electric signal to, uses central processing unit to carry out the analysis and the processing of data again.Mainly form by signals collecting, signal analysis and auxiliary unit and three parts of signal Processing.
1, signals collecting: form by temperature sense circuit, humidity inductive circuit, A/D change-over circuit;
The humidity inductive probe is humicap C1; Has absolute interchangeability; High reliability and long-time stability, the response time is characteristics fast, are applicable to linear voltage output and two kinds of circuit of frequency output; Humicap is equivalent to a capacitor element in circuit constitutes, its electric capacity increases along with the increase of survey air humidity.Integrated circuit U2 by four independently operational amplifier form; Utilize humicap C1 electric capacity along with the variation capacitance of survey air humidity changes thereupon; Thereby change the characteristic of the time of in circuit, charging and discharging; Constitute oscillatory circuit with integrated circuit U2, resistance R 1-R8, capacitor C 1-C3, output frequency value, the capacitance variation amount that is about to humicap C1 changes the signal that central processing unit is accepted exactly into.The capacitance measurement of humicap C1 is all surveyed under the 10MHz condition, not must operate at 5K-100KHz but sensor has restriction, can do correction with following formula:
CfkHz＝CfkHz(1.027-0.01185Ln(fkHz))
The temperature sense probe is RTD R11; Have excellent linearity and stable between RTD and the temperature, utilize RTD to be worth mutagenic characteristic with the changes in resistance of environment temperature, resistance R 9-R14 forms electric bridge in the humidity inductive circuit; Output analog quantity voltage signal is given the A/D change-over circuit; Be core with integrated circuit U4 promptly, integrated circuit U4 is 12 a high-precision a/d converter, the analog quantity voltage signal that receives is changed into digital signal send central processing unit to.RTD is one of the most stable normal component of temperature survey, and the device computing formula is:
RT＝R0(1+AT+BT2+C(T-100)T3)
Wherein: A=3.9083E-3
B＝-5.775E-7
C＝-4.183E-12
2, signal analysis and auxiliary unit: single-chip microcomputer processing unit, reset circuit, crystal oscillating circuit, eight toggle switch circuit of two-way are formed;
Central processor unit is integrated circuit U1; The digital signal of temperature sense module that receives and the transmission of humidity inductive module is analyzed and computing; When calibrating simultaneously according to Temperature Humidity Sensor to eight toggle switch settings of two-way; Read the temperature and humidity offset data, temperature and humidity compensation is technological automatically in real time in the central processing unit handling procedure, and it is integrated circuit U3 that the most high-precision digital signal sends the D/A change-over circuit to; Avoided the output accuracy of traditional Temperature Humidity Sensor mainly to lean on calibrations such as potentiometer, adjustable resistance, the shortcoming that measuring accuracy is difficult to guarantee.The auxiliary unit circuit is reset circuit and crystal oscillating circuit, resets reliably and clock for its operate as normal provides.
3, signal Processing: the output circuit of D/A change-over circuit, transmitter and current/voltage holding circuit, temperature and humidity analog quantity is formed;
The D/A change-over circuit is a core with integrated circuit U3 promptly; Integrated circuit U3 is a kind of two-way able to programme 12 figure place mould conversion chips that have the input of buffering benchmark; Output voltage range is the twice of reference voltage; D/A converter receives 16 words that are used to programme and produces simulation output, and Output Voltage Formula is:
2(VREFIN)CODE/4096
Calculate the temperature and humidity magnitude of voltage of conversion according to the D/A converter formula, send transmitter and electric current and voltage holding circuit H to through D/A converter two-way output pin.Transmitter is to be the discharge circuit of core composition with integrated circuit U5A and U5B, and according to the short empty disconnected rule of void, it is connector J1 output 4-20mA electric current through the output circuit of temperature and humidity analog quantity that voltage signal finally is converted into current signal.The current/voltage holding circuit is made up of TVS protection tube D3, D4, resettable fuse F1, F2, F3, makes and obtains better protection in the Temperature Humidity Sensor installation and operation.
Claims (1)
1. digital humiture pick-up unit; It is characterized in that; Form by temperature sense circuit A, humidity inductive circuit B, eight toggle switch circuit of two-way C, A/D change-over circuit D, reset circuit E, central processor unit F, crystal oscillating circuit G, D/A change-over circuit I, fluff device and electric current and voltage holding circuit H and temperature and humidity analogue quantity output circuit J; Wherein temperature sense circuit A, humidity inductive circuit B, A/D change-over circuit D, central processor unit F, D/A change-over circuit I, fluff device and electric current and voltage holding circuit H, temperature and humidity analogue quantity output circuit J form main circuit; Eight toggle switch circuit of two-way C provides the temperature and humidity offset data when Temperature Humidity Sensor is calibrated; Reset circuit E, the beautiful single-chip microcomputer processing unit of crystal oscillating circuit G F are connected to its work and provide support, wherein:
Temperature sense circuit A is made up of integrated circuit U4, resistance R 9-R14, capacitor C 4, C5, C15, and wherein resistance R 11 is a RTD, i.e. the temperature sense probe; Between 7 pin and power supply 4.2V of resistance R 9 and R12 series connection integrated circuit U4, between resistance R 11 1 ends economize on electricity resistance R9, the R12, other end ground connection; Resistance R 10 and R13 are series at power supply 4.2V and connect between 8 pin of integrated circuit U4, between resistance R 14 1 terminating resistor R10, the R13, and other end ground connection; Capacitor C 15 also connects 7,8 pin of integrated circuit U4; Capacitor C 5 connects between 7 pin and ground wire of integrated circuit U4, and capacitor C 4 also connects between 8 pin and ground wire of integrated circuit U4, wherein capacitor C 4, C5 ground connection;
Humidity inductive circuit B is made up of integrated circuit U2, resistance R 1-R8, capacitor C 1-C3, and wherein C1 is a humicap, i.e. humidity inductive probe, and resistance R 4 also connects 1,12 pin of U2; Resistance R 2 also connects 1,6 pin of U2, and resistance R 3 also connects 6,12 pin of U2, and resistance R 1 also connects 1,7 pin of U2; Resistance R 7 also connects 6,3 pin of U2, and resistance R 8 also connects 3,10 pin of U2, and capacitor C 1 also connects 7,3 pin of U2; Capacitor C 2, C3 also connect 3,12 pin of U2, the 3 pin ground connection of U2, and 12 pin meet power supply 5V;
Eight toggle switch circuit of two-way C is made up of toggle switch SW8-1 and SW8-2, exclusion PS9-1 and PS9-2; The 1-8 pin of toggle switch SW8-1 links to each other with the 2-9 pin of exclusion PS9-1 respectively; The 9-16 pin ground connection of toggle switch SW8-1,1 pin of exclusion PS9-1 connects the 5V power supply, and the 1-8 pin of toggle switch SW8-2 links to each other with the 2-9 pin of exclusion PS9-2 respectively; The 9-16 pin ground connection of toggle switch SW8-2,1 pin of exclusion PS9-2 connects the 5V power supply;
A/D change-over circuit D is made up of integrated circuit U4, crystal oscillator XT2, capacitor C 6 and C7; 5 pin of integrated circuit U4,9 pin, 15 pin connect 3V, 1.2V, 3V power supply respectively; The two ends of crystal oscillator XT2 connect 2 pin and 3 pin of integrated circuit U4 respectively; Capacitor C 6, C7 connect ground connection behind the two ends of crystal oscillator XT2 respectively, and 1 pin of integrated circuit U4,12 pin, 13 pin connect 7 pin, 12 pin, 13 pin of integrated circuit U1 respectively; The 16 pin ground connection of integrated circuit U4;
Reset circuit E is made up of capacitor C 8 and resistance R 15, and resistance R 15 connects between 10 pin and ground wire of integrated circuit U1, a termination 5V of capacitor C 8,10 pin of the other end integrated circuit U1 of capacitor C 8;
Central processor unit F is made up of integrated circuit U1, and 44 pin of integrated circuit U1 connect the 5V power supply, the 22 pin ground connection of integrated circuit U1;
Crystal oscillating circuit G is made up of crystal oscillator XT1, capacitor C 13, C14, and the two ends of crystal oscillator XT1 connect 20,21 pin of integrated circuit U1 respectively, and capacitor C 13, C14 connect ground connection behind the two ends of crystal oscillator XT1 respectively;
D/A change-over circuit I is made up of integrated circuit U3 and capacitor C 9; The 7 pin connecting resistance R16 of integrated circuit U3; 6 pin are connected 2.1V, 5V power supply respectively with 8 pin, the 5 pin ground connection of U3, and 1 pin of U3,2 pin, 3 pin connect 15 pin, 16 pin, 17 pin of integrated circuit U1 respectively; 4 pin connecting resistance R17, capacitor C 9 also connects 5,8 pin of integrated circuit U3;
Transmitter and electric current and voltage holding circuit H be by resistance R 16-R24, capacitor C 10, C11, diode D1, D2, D5; Triode Q1 and Q2, diode D1-D4, fuse F1-F3; Integrated circuit U5A, U5B and plug connector J1 form, and the two ends of resistance R 16 connect 7 pin of integrated circuit U3 respectively, 3 pin of U5A; Capacitor C 10 also connects 3,11 pin of U5A, the 11 pin ground connection of U5A, and 4 pin connect the 10V power supply; Resistance R 18, diode D5, fuse F1 and capacitor C 12 are serially connected between 1 pin of 4 pin and plug connector J1 of U5A, and the 1 pin crosstalk resistance R19 of U5A connects the base stage of triode Q1, and the 2 pin crosstalks resistance R20 of U5A connects the emitter of triode Q1; Diode D1 also connects between the base stage and emitter of triode Q1; The emitter of triode Q1 is crosstalk resistance R21 ground connection also, and the collector series connection fuse F3 of triode Q1 patches 1 pin of fitting J1, and 1,2 pin of diode D3 and capacitor C 12 and plug connector also connect; The 4 pin crosstalks resistance R17 of integrated circuit U3 connects 5 pin and the ground connection of integrated circuit U5B, and the 7 pin crosstalks resistance R22 of U5B connects the base stage of triode Q2, and the 6 pin crosstalks resistance R23 of U5B connects triode! 2 emitter, the emitter of triode Q2 be crosstalk resistance R24 ground connection also, and base stage and the emitter of diode D2 and triode Q2 also connects, and the collector crosstalk of triode Q2 hinders 3 pin that fuse patches fitting, and diode D4 and capacitor C 13 also patch 2/3 pin of fitting J1;
Temperature and humidity analogue quantity output circuit J is made up of connector J1, and 1 pin is public ground, and 2 pin are the output of humidity analog quantity, and 3 pin are the output of temperature simulation amount;
The humiture collecting method is following:
Temperature Humidity Sensor be with central processing unit be integrated circuit U1 be core one the cover detection system; Based on high sensitivity and the controllability of central processing unit to digital signal; According to the situation of change of the temperature in the field monitoring scope, humidity, the real-time humiture induction module that passes through carries out the collection of signal and converts electric signal to, uses central processing unit to carry out the analysis and the processing of data again; Form by signals collecting, signal analysis and auxiliary unit and three parts of signal Processing, wherein:
1) signals collecting: form by temperature sense circuit, humidity inductive circuit, A/D change-over circuit;
The humidity inductive probe is humicap C1, has absolute interchangeability, high reliability and long-time stability; Response time is characteristics fast, are applicable to linear voltage output and two kinds of circuit of frequency output, and humicap is equivalent to a capacitor element in circuit constitutes; Its electric capacity increases along with the increase of survey air humidity; Integrated circuit U2 by four independently operational amplifier form, utilize humicap C1 electric capacity along with the variation capacitance of survey air humidity changes thereupon, thereby change the characteristic of the time of charging and discharge in circuit; Constitute oscillatory circuit with integrated circuit U2, resistance R 1-R8, capacitor C 1-C3; Output frequency value, the capacitance variation amount that is about to humicap C1 changes the signal that central processing unit is accepted exactly into, and the capacitance measurement of humicap C1 is all surveyed under the 10MHz condition; But sensor not restriction must operate at 5K-100KHz, can do correction with following formula:
CfkHz＝CfkHz(1.027-0.01185Ln(fkHz))
The temperature sense probe is RTD R11; Have excellent linearity and stable between RTD and the temperature, utilize RTD to be worth mutagenic characteristic with the changes in resistance of environment temperature, resistance R 9-R14 forms electric bridge in the humidity inductive circuit; Output analog quantity voltage signal is given the A/D change-over circuit; Be core with integrated circuit U4 promptly, integrated circuit U4 is 12 a high-precision a/d converter, the analog quantity voltage signal that receives is changed into digital signal send central processing unit to; RTD is one of the most stable normal component of temperature survey, and the device computing formula is:
RT＝R0(1+AT+BT2+C(T-100)T3)
Wherein: A=3.9083E-3
B＝-5.775E-7
C＝-4.183E-12
2) signal analysis and auxiliary unit: single-chip microcomputer processing unit, reset circuit, crystal oscillating circuit, eight toggle switch circuit of two-way are formed;
Central processor unit is integrated circuit U1; The digital signal of temperature sense module that receives and the transmission of humidity inductive module is analyzed and computing; When calibrating simultaneously according to Temperature Humidity Sensor to eight toggle switch settings of two-way; Read the temperature and humidity offset data, temperature and humidity compensation is technological automatically in real time in the central processing unit handling procedure, and it is integrated circuit U3 that the most high-precision digital signal sends the D/A change-over circuit to; Avoided the output accuracy of traditional Temperature Humidity Sensor mainly to lean on calibrations such as potentiometer, adjustable resistance; The shortcoming that measuring accuracy is difficult to guarantee, auxiliary unit circuit are reset circuit and crystal oscillating circuit, reset reliably and clock for its operate as normal provides;
3) signal Processing: the output circuit of D/A change-over circuit, transmitter and current/voltage holding circuit, temperature and humidity analog quantity is formed;
The D/A change-over circuit is a core with integrated circuit U3 promptly; Integrated circuit U3 is a kind of two-way able to programme 12 figure place mould conversion chips that have the input of buffering benchmark; Output voltage range is the twice of reference voltage; D/A converter receives 16 words that are used to programme and produces simulation output, and Output Voltage Formula is:
2(VREFIN)CODE/4096
Calculate the temperature and humidity magnitude of voltage of conversion according to the D/A converter formula; Send transmitter and electric current and voltage holding circuit H to through D/A converter two-way output pin; Transmitter is to be the discharge circuit of core composition with integrated circuit U5A and U5B; According to the short empty disconnected rule of void; It is connector J1 output 4-20mA electric current through the output circuit of temperature and humidity analog quantity that voltage signal finally is converted into current signal, and the current/voltage holding circuit is made up of TVS protection tube D3, D4, resettable fuse F1, F2, F3, makes and obtains better protection in the Temperature Humidity Sensor installation and operation.
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| CN2012100228911A CN102589614A (en) | 2012-02-02 | 2012-02-02 | Digital temperature and humidity detection device |
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| CN2012100228911A CN102589614A (en) | 2012-02-02 | 2012-02-02 | Digital temperature and humidity detection device |
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| CN102589614A true CN102589614A (en) | 2012-07-18 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102866242A (en) * | 2012-10-19 | 2013-01-09 | 程培峰 | Rock and soil humidity testing system and method for achieving rock and soil humidity monitoring by adopting same |
| CN103528628A (en) * | 2013-10-29 | 2014-01-22 | 上海工程技术大学 | Humiture data acquisition method |
| CN104280064A (en) * | 2013-07-12 | 2015-01-14 | 魏燕 | Configuration type multi-parameter wireless physicochemical index monitor |
| CN105971976A (en) * | 2016-05-25 | 2016-09-28 | 广西柳工机械股份有限公司 | Method for measuring hydraulic pressure of engineering machine by means of voltage type pressure sensor |
| CN107402046A (en) * | 2017-08-16 | 2017-11-28 | 广西柳城县绿之缘生态农业科技有限公司 | A kind of environment monitoring device based on agricultural sightseeing tourism special zone |
| CN111998895A (en) * | 2020-08-26 | 2020-11-27 | 广东电网有限责任公司广州供电局 | Humidity monitoring method and device |
| CN113109516A (en) * | 2021-04-21 | 2021-07-13 | 江南大学 | Humidity sensor response and recovery time measuring device and method |
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- 2012-02-02 CN CN2012100228911A patent/CN102589614A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102866242A (en) * | 2012-10-19 | 2013-01-09 | 程培峰 | Rock and soil humidity testing system and method for achieving rock and soil humidity monitoring by adopting same |
| CN104280064A (en) * | 2013-07-12 | 2015-01-14 | 魏燕 | Configuration type multi-parameter wireless physicochemical index monitor |
| CN103528628A (en) * | 2013-10-29 | 2014-01-22 | 上海工程技术大学 | Humiture data acquisition method |
| CN105971976A (en) * | 2016-05-25 | 2016-09-28 | 广西柳工机械股份有限公司 | Method for measuring hydraulic pressure of engineering machine by means of voltage type pressure sensor |
| CN107402046A (en) * | 2017-08-16 | 2017-11-28 | 广西柳城县绿之缘生态农业科技有限公司 | A kind of environment monitoring device based on agricultural sightseeing tourism special zone |
| CN111998895A (en) * | 2020-08-26 | 2020-11-27 | 广东电网有限责任公司广州供电局 | Humidity monitoring method and device |
| CN111998895B (en) * | 2020-08-26 | 2022-07-08 | 广东电网有限责任公司广州供电局 | Humidity monitoring method |
| CN113109516A (en) * | 2021-04-21 | 2021-07-13 | 江南大学 | Humidity sensor response and recovery time measuring device and method |
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Application publication date: 20120718 |