CN100451636C - Humidity transmitter in low cost - Google Patents
Humidity transmitter in low cost Download PDFInfo
- Publication number
- CN100451636C CN100451636C CNB2006100468500A CN200610046850A CN100451636C CN 100451636 C CN100451636 C CN 100451636C CN B2006100468500 A CNB2006100468500 A CN B2006100468500A CN 200610046850 A CN200610046850 A CN 200610046850A CN 100451636 C CN100451636 C CN 100451636C
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- circuit
- output
- humidity
- humidity transmitter
- transmitter
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Abstract
The present invention relates to a humidity transmitter with low cost, particularly to a humidity transmitter with 4 to 20 mA output or 0 to 5 V output, which is composed of a shell body and a control circuit board, wherein a humidity detecting circuit formed by a humidity sensor HS1101, a wave filtering and amplifying circuit formed by an integrated circuit OP 295, a 4 to 20 mA output circuit formed by an amplifier OP295 and triodes 9014, BD237 and a 0 to 5V output circuit formed by a current-voltage convertor RC420 are arranged on the control circuit board. The present invention has the advantages of simple structure, low cost and good measuring precision, and is suitable for daily and industrial process control.
Description
Technical field
The present invention relates to a kind of humidity transmitter, particularly relate to a kind of humidity transmitter with 4～20mA output or 0～5V output.
Background technology
The measurement of humidity and control are widely used in the middle of our daily life and industrial process, because thin-film capacitor humidity transmitter volume is little, cost is low, use simple, convenient, reaction is fast, and measurement range is wide, and has the characteristic that some other pollutants disturb in the long-term opposing film surface condensation water and air, therefore more and more come into one's own, the possibility that replaces the electric resistance humidity sensor is arranged greatly.
Summary of the invention
The purpose of this invention is to provide a kind of humidity transmitter with 4～20mA output or 0～5V output.Filtering and amplifying circuit and 4～20mA output circuit that its adopts humidity measuring circuit that humidity sensor makes up, is made up by the OP295 amplifier, 0～5V output circuit by current-to-voltage converter RCV420 structure, make complete machine structure simple, cost is low, has measuring accuracy preferably.
The present invention is achieved by the following technical solutions:
A kind of humidity transmitter cheaply is made up of housing, control circuit board, and control circuit board is provided with by the humidity measuring circuit of moisture sensor structure, by 4～20mA output circuit of amplifier and triode structure and the 0～5V output circuit that is made up by RCV420.
The ic 555 IC circuit of aforesaid humidity measuring circuit
1With R
1, R
2, C
1Form multivibrator; Monostalbe trigger is by the ic 555 IC circuit
2, R
3And moisture sensor HS1101 forms.
Aforesaid 4～20mA output circuit is provided with power conversion LM317 and potentiometer W
1And W
2, electric current output 9014 and BD237 and resistance R L.
Power supply 0～24V of current-to-voltage converter RCV420,4～20mA current output circuit connect 1 and 16 pin of RCV420 in aforesaid 0～5V output circuit, 2,4,5,12 pin of RCV420 all connect 0V, 15 and 14 pin are connected to the negative terminal of output, and 10,11 and 13 are connected to the anode of output.
Advantage of the present invention and effect are:
1. the present invention uses flexibly, cost is low, has good practicability, its testing circuit also can be used as the signal deteching circuit of other capacitive transducer, its output circuit also can only be used the output of 4～20mA electric current, its output also can be used as other sensor, as the signal processing circuit of products such as pressure transducer, thermistor.
2. complete machine structure of the present invention is simple, and cost is low, has measuring accuracy preferably, is suitable for the control of daily life and industrial process.
Description of drawings
Fig. 1 of the present invention is the humidity measuring circuit circuit diagram;
Fig. 2 of the present invention is 4～20mA output circuit figure;
Fig. 3 of the present invention is that 4～20mA is transformed to 0～5V circuit diagram.
Embodiment
The present invention includes housing, control circuit board, foregoing circuit built-up circuit plate is placed in the housing and constitutes the whole effect that can realize humidity transmitter with sensing element.
A kind of humidity transmitter cheaply is made up of housing, control circuit board.Control circuit board is provided with multivibrator and the monostalbe trigger of being made up of two 555 circuit and moisture sensor, the amplification filtering circuit that they and OP295 form etc. constitute humidity measuring circuit, will change the variation that the capacitance variations that causes converts voltage to by humidity and finish Humidity Detection.Control circuit board is provided with LM317 and makes power conversion, 24V is become 5.0V gives humidity testing circuit and amplifier OP295 power supply, 9014 and BD237 make electric current output, potentiometer W
1And W
2Be respectively applied for zeroising and transfer range, resistance R L is used for line transfer.Control circuit board is provided with current-to-voltage converter RCV420, and 4～20mA is transformed to 0～5V.
In the humidity measuring circuit circuit diagram, 555 IC circuit
1With R
1, R
2, C
1, C
5Connect to form multivibrator, its oscillation frequency f=1.44/ (R
1+ 2R
2) C
1, resistance R
1Connect IC
11,4 pin, resistance R
2Connect IC
11,2 pin, capacitor C
1Connect IC
16,7 pin, capacitor C
5Connect IC
13,7 pin, oscillator is by the trigger action monostalbe trigger of 5 pin output.Monostalbe trigger is by IC
2, R
3And the moisture sensor composition, output pulse width depends on charging rate R
3(C
2+ C
x) numerical value, that is: t=1.1R
3(C
2+ C
x).This output pulse involves amplifying circuit after filtration, is converted into the d. c. voltage signal that changes with humidity.
Among 4～20mA output circuit figure, LM317 makes power conversion, 24V is become 5.0V give humidity testing circuit and amplifier OP295 power supply, 8 of OP295 is connected the positive and negative of power supply respectively with 4 pin, the voltage signal of humidity measuring circuit output is input to current conversion circuit, potentiometer W by the pin 5 and 6 of OP295 amplifier
1And W
2Be respectively applied for zeroising and transfer range, the base stage of triode 9014 is connected with the pin 7 of OP295 amplifier, 9014 emitter connects the base stage of BD237,9014 collector is connected with the collector of BD237, by resistance connection+24V, the emitter of BD237 links to each other with ground by resistance, 9014 and BD237 do electric current output, resistance R L is used for line transfer.
4～20mA is transformed in 0～5V circuit diagram, power supply 0～24V of RCV420,4～20mA current output circuit connects 1 and 16 pin of current-to-voltage converter RCV420,2,4,5,12 pin of RCV420 all connect 0V, 15 and 14 pin are connected to the negative terminal of output, and 10,11 and 13 are connected to the anode of output.
Claims (3)
- One kind cheaply humidity transmitter form by housing, control circuit board, control circuit board is provided with by the humidity measuring circuit of moisture sensor structure, by 4～20mA output circuit of amplifier and triode structure and the 0～5V output circuit that is made up by current-to-voltage converter RCV420, it is characterized in that its ic 555 IC circuit of humidity measuring circuit that described moisture sensor makes up 1With R 1, R 2, C 1Form multivibrator; Its monostalbe trigger is by the ic 555 IC circuit 2, R 3And moisture sensor is formed.
- 2. according to the described a kind of humidity transmitter cheaply of claim 1, it is characterized in that its oscillation frequency of described multivibrator f=1.44/ (R 1+ 2R 2) C 1
- 3. according to the described a kind of humidity transmitter cheaply of claim 1, it is characterized in that described monostalbe trigger charging rate that output pulse width depends on is: t=1.1R 3(C 2+ C x).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100468500A CN100451636C (en) | 2006-06-09 | 2006-06-09 | Humidity transmitter in low cost |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100468500A CN100451636C (en) | 2006-06-09 | 2006-06-09 | Humidity transmitter in low cost |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1873402A CN1873402A (en) | 2006-12-06 |
| CN100451636C true CN100451636C (en) | 2009-01-14 |
Family
ID=37483934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100468500A Expired - Fee Related CN100451636C (en) | 2006-06-09 | 2006-06-09 | Humidity transmitter in low cost |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100451636C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103868954A (en) * | 2014-03-25 | 2014-06-18 | 成都国科海博信息技术股份有限公司 | Grain humidity detection circuit |
| CN103999742A (en) * | 2014-04-28 | 2014-08-27 | 重庆三峡学院 | Timed multi-point automatic irrigation machine system |
| CN107607583B (en) * | 2017-08-29 | 2020-08-04 | 广东美的厨房电器制造有限公司 | Humidity detection device |
| CN108158725A (en) * | 2017-12-18 | 2018-06-15 | 季梅 | A kind of paper diaper immersion intelligent monitoring circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2220641Y (en) * | 1994-09-01 | 1996-02-21 | 电子工业部第四十九研究所 | Humidity transmitter |
| CN2570782Y (en) * | 2002-09-27 | 2003-09-03 | 北京农业信息技术研究中心 | Intelligent humiture self-compensation sensing transducer |
| CN201016951Y (en) * | 2006-06-09 | 2008-02-06 | 沈阳化工学院 | Low-cost humidity transducer |
-
2006
- 2006-06-09 CN CNB2006100468500A patent/CN100451636C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2220641Y (en) * | 1994-09-01 | 1996-02-21 | 电子工业部第四十九研究所 | Humidity transmitter |
| CN2570782Y (en) * | 2002-09-27 | 2003-09-03 | 北京农业信息技术研究中心 | Intelligent humiture self-compensation sensing transducer |
| CN201016951Y (en) * | 2006-06-09 | 2008-02-06 | 沈阳化工学院 | Low-cost humidity transducer |
Non-Patent Citations (4)
| Title |
|---|
| 液位变送器输出的变换. 孙立红等.今日电子，第7期. 2004 |
| 液位变送器输出的变换. 孙立红等.今日电子，第7期. 2004 * |
| 湿度传感器及其变送器. 崔敬花等.沈阳化工学院学报，第15卷第3期. 2001 |
| 湿度传感器及其变送器. 崔敬花等.沈阳化工学院学报，第15卷第3期. 2001 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1873402A (en) | 2006-12-06 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090114 Termination date: 20110609 |