CN102425702B - HART (highway addressable remote transducer) transmission circuit applying to valve positioner - Google Patents
HART (highway addressable remote transducer) transmission circuit applying to valve positioner Download PDFInfo
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- CN102425702B CN102425702B CN 201110357099 CN201110357099A CN102425702B CN 102425702 B CN102425702 B CN 102425702B CN 201110357099 CN201110357099 CN 201110357099 CN 201110357099 A CN201110357099 A CN 201110357099A CN 102425702 B CN102425702 B CN 102425702B
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Abstract
The invention relates to an HART (highway addressable remote transducer) transmission circuit applying to a valve positioner. A transformer coupling mode is got rid of the circuit; integrated circuit coupling signals are adopted; the modern semiconductor technology ensures an integrated circuit element to be far higher than a transformer element of a mechanical structure in aspects of manufacturing process, reliability and the like, and the reliability and yield of products are improved greatly. The HART transmission circuit provided by the invention has the beneficial effects that the HART signal transmission and coupling function is realized by utilizing the integrated circuit element; defects of great circuit volume and low yield and the like brought about by the transformer coupling mode are overcome; and the circuit has high reliability, is convenient to weld and debug, and is convenient for large-scale batch production.
Description
Technical field
The present invention relates to a kind of HART circuit, particularly a kind of HART emitting circuit that is applied to valve positioner.
Background technique
Valve positioner acts on the modulating valve, is widely used in the fields such as oil, chemical industry, electric power, food and water treatment.Along with the fast development of computer bus technology, traditional analogue instrument is replaced, but should see that simultaneously the analogue signal system still occupies very large proportion within current period by intelligent, bus-type instrument gradually.The HART(highway addressable remote transducer)
As the transitional product of analog system in the number system transition process, realized superposed transmission digital signal in analogue signal, have the stronger market competitiveness in current period.At present, the known HART emitting circuit that is applied to valve positioner adopts transformer-coupled mode, adopts the circuit of this mode to have the shortcomings such as volume is large, yield rate is low, causes very large difficulty for installation, the debugging work of product.
Summary of the invention
In order to overcome the known shortcoming that HART emitting circuit volume is large, yield rate is low that is applied to valve positioner, the utility model provides a kind of HART emitting circuit that is applied to valve positioner, this circuit has been abandoned transformer-coupled mode, adopt the intergrated circuit coupled signal, modern semiconductor technology has guaranteed that integrated circuit component is higher than the transformer element of mechanical structure formula far away at aspects such as preparation process, reliabilities, and reliability, the yield rate tool of product had greatly improved.
The present invention for achieving the above object, the technological scheme that adopts is: a kind of HART emitting circuit that is applied to valve positioner, it is characterized in that: node OTXA links to each other with in-phase input end 5 pin of operational amplifier U1B by resistance R 9 in the described circuit, reference voltage V ref connects in-phase input end 5 pin of operational amplifier U1B, node OTXA is by the end of capacitor C 4 contact resistance R7, the other end of resistance R 7 links to each other with inverting input 6 pin of operational amplifier U1B, capacitor C 3 is in parallel with resistance R 6, inverting input 6 pin of amplifier U1B are pressed respectively at two ends in parallel with computing, output terminal 7 pin link to each other, the end of the output terminal 7 pin connecting resistance R8 of operational amplifier U1B, the other end connecting resistance R10 one end of resistance R 8 and an end of capacitor C 5, the other end ground connection of resistance R 10, in-phase input end 3 pin of another termination operational amplifier U1A of capacitor C 5 and an end of resistance R 1, another termination 4～20mA input end I+ of resistance R 1, one end of capacitor C 1, the drain D of N channel enhancement field effect transistor Q1, the positive pole of diode D1, the negative pole of diode D1 connects the source S of effect pipe Q1 by diode D2,4～20mA output terminal I-and ground, capacitor C 2 is in parallel with resistance R 5, resistance R 5 one end ground connection, the end of resistance R 5 the other end connecting resistance R2 and inverting input 2 pin of operational amplifier U1A, another termination reference voltage V ref of resistance R 2, the grounding end 4 pin ground connection of operational amplifier U1A, power supply side 8 pin meet power supply VCC, the end of output terminal 1 pin connecting resistance R4, the grid G of the end of the other end connecting resistance R3 of resistance R 4 and N channel enhancement field effect transistor Q1, the other end of another termination capacitor C 1 of resistance R 3.
The invention has the beneficial effects as follows: use integrated circuit component to realize HART signal emission coupling function, overcome the circuit volume that transformer coupled mode brings large, the shortcoming such as yield rate is low.Circuit reliability is high, and welding, debugging conveniently are convenient to large-scale mass production.
Description of drawings
Fig. 1 is circuit theory diagrams of the present invention.
Embodiment
In Fig. 1, the OTXA node is the output terminal of HART modem chip, and the signal baud rate is 1200, and " 1 " is frequency 1200Hz square wave, and " 0 " is frequency 2200Hz square wave.Be connected to by operational amplifier U1B contact resistance R6, resistance R 7, resistance R 8, resistance R 10, capacitor C 3 by capacitor C 4 filtering direct current signals and consist of active low-pass filter, it is the reference voltage V ref of VCC/2 that the in-phase input end of operational amplifier U1B connects size, and square signal is carried out being connected with the in-phase input end of operational amplifier U1A by filter capacitor C5 behind the filter shape.Resistance R 2 links to each other with ground with reference voltage V ref with resistance R 5 series connection, for the amplification circuit centered by operational amplifier U1A provides quiescent operation point, diode D1 and diode D2 series connection, be connected on 4～20mA input I+ and the 4～20mA output I-, under the being on the scene effect pipe Q1 off state, 4～20mA electric current flows through from diode D1 and diode D2, the voltage of node 4～20mA input this moment I+ is the conducting voltage sum of diode D1 and diode D2, is connected by the in-phase input end of resistance R 1 with operational amplifier U1A.The be added to in-phase input end of operational amplifier U1A of HART signal, output terminal at U1A produces the identical alternating signal of frequency, resistance R 3 and capacitor C 1 are connected between the drain D and grid G of N channel enhancement field effect transistor Q1, the voltage signal that is superimposed upon on the field effect transistor Q1 is carried out shaping, the break-make of control N channel enhancement field effect transistor Q1, change the voltage at 4～20mA input I+ and 4～20mA output I-two ends, thereby affect loop current, frequency is identical with the OTXA input, realizes superimposed digital signal on 4～20mA analogue signal.
Claims (1)
1. HART emitting circuit that is applied to valve positioner, it is characterized in that: node OTXA links to each other with in-phase input end 5 pin of operational amplifier U1B by resistance R 9 in the described circuit, reference voltage V ref connects in-phase input end 5 pin of operational amplifier U1B, node OTXA is by the end of capacitor C 4 contact resistance R7, the other end of resistance R 7 links to each other with inverting input 6 pin of operational amplifier U1B, capacitor C 3 is in parallel with resistance R 6, inverting input 6 pin of amplifier U1B are pressed respectively at two ends in parallel with computing, output terminal 7 pin link to each other, the end of the output terminal 7 pin connecting resistance R8 of operational amplifier U1B, the other end connecting resistance R10 one end of resistance R 8 and an end of capacitor C 5, the other end ground connection of resistance R 10, in-phase input end 3 pin of another termination operational amplifier U1A of capacitor C 5 and an end of resistance R 1, another termination 4～20mA input end I+ of resistance R 1, one end of capacitor C 1, the drain D of N channel enhancement field effect transistor Q1, the positive pole of diode D1, the negative pole of diode D1 connects the source S of effect pipe Q1 by diode D2,4～20mA output terminal I-and ground, capacitor C 2 is in parallel with resistance R 5, resistance R 5 one end ground connection, the end of resistance R 5 the other end connecting resistance R2 and inverting input 2 pin of operational amplifier U1A, another termination reference voltage V ref of resistance R 2, the grounding end 4 pin ground connection of operational amplifier U1A, power supply side 8 pin meet power supply VCC, the end of output terminal 1 pin connecting resistance R4, the grid G of the end of the other end connecting resistance R3 of resistance R 4 and N channel enhancement field effect transistor Q1, the other end of another termination capacitor C 1 of resistance R 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110357099 CN102425702B (en) | 2011-11-11 | 2011-11-11 | HART (highway addressable remote transducer) transmission circuit applying to valve positioner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110357099 CN102425702B (en) | 2011-11-11 | 2011-11-11 | HART (highway addressable remote transducer) transmission circuit applying to valve positioner |
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| Publication Number | Publication Date |
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| CN102425702A CN102425702A (en) | 2012-04-25 |
| CN102425702B true CN102425702B (en) | 2013-05-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201110357099 Active CN102425702B (en) | 2011-11-11 | 2011-11-11 | HART (highway addressable remote transducer) transmission circuit applying to valve positioner |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113790304B (en) * | 2021-08-23 | 2023-11-14 | 浙江中控技术股份有限公司 | Intrinsic safety HART communication system for intelligent valve positioner |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1514596A (en) * | 2002-12-31 | 2004-07-21 | 浙江浙大中控技术有限公司 | Modulator-demodulator based on single chip machine and its method of realizing HART protocol signal transmission |
| CN201349198Y (en) * | 2008-10-20 | 2009-11-18 | 杭州晶华微电子有限公司 | HART modem |
| CN101650572A (en) * | 2009-09-07 | 2010-02-17 | 上海自动化仪表股份有限公司 | Intelligent electric valve positioner based on HART communication |
| CN202327344U (en) * | 2011-11-11 | 2012-07-11 | 中环天仪股份有限公司 | HART (Highway Addressable Remote Transducer) transmitting circuit applied to valve locator |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010108803A2 (en) * | 2009-03-25 | 2010-09-30 | Endress+Hauser Conducta Gesellschaft Für Mess- Und Regeltechnik Mbh+Co. Kg | Method and circuit for signal transmission via a current loop |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1514596A (en) * | 2002-12-31 | 2004-07-21 | 浙江浙大中控技术有限公司 | Modulator-demodulator based on single chip machine and its method of realizing HART protocol signal transmission |
| CN201349198Y (en) * | 2008-10-20 | 2009-11-18 | 杭州晶华微电子有限公司 | HART modem |
| CN101650572A (en) * | 2009-09-07 | 2010-02-17 | 上海自动化仪表股份有限公司 | Intelligent electric valve positioner based on HART communication |
| CN202327344U (en) * | 2011-11-11 | 2012-07-11 | 中环天仪股份有限公司 | HART (Highway Addressable Remote Transducer) transmitting circuit applied to valve locator |
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| CN102425702A (en) | 2012-04-25 |
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