CN102879018A - Platinum resistance and analogous current transducing circuit - Google Patents
Platinum resistance and analogous current transducing circuit Download PDFInfo
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- CN102879018A CN102879018A CN2012103466019A CN201210346601A CN102879018A CN 102879018 A CN102879018 A CN 102879018A CN 2012103466019 A CN2012103466019 A CN 2012103466019A CN 201210346601 A CN201210346601 A CN 201210346601A CN 102879018 A CN102879018 A CN 102879018A
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Abstract
The invention relates to a platinum resistance and analogous current transducing circuit, and the present analog quantity transducer has simplex function. The circuit mainly includes a platinum resistance measuring circuit, an analogous current measuring circuit, a measuring channel selection circuit, a voltage and current converting circuit, a voltage value output interface, a current value output interface, a measuring channel selection interface and a multi-power-supply supply interface, wherein the analogous current measuring circuit, the platinum resistance measuring circuit, the measuring channel selection circuit and the voltage and current converting circuit are the core of the circuit; and the voltage value output interface, the current value output interface, the measuring channel selection interface and the multi-power-supply supply interface are peripheral interfaces, and are mainly formed by socket connectors. The platinum resistance and an analogous current transducing circuit integrates the platinum resistance temperature measurement capability and the 4-20 mA analogous current measuring capability, is available for measuring channel selection, and has the characteristics of high precision, small size, modularization, low cost, high stability and the like.
Description
Technical field
The present invention relates to the converter that a kind of field of industrial production analog sensor is equipped with, be specially a kind of transmission circuit that has platinum resistance temperature survey and 4～20mA analog current measurement capability and can measure channel selecting.
Background technology
" instrument automation " of industrial processes is the trend of current industrial development, and detection is the important step of production run, and it is the basis of realizing automatic regulation and control.Only have the information of detection accurately, reliably, and reach industrial requirement, could feed back in the industrial processes again as the parameter of calculating parameter or control action and go.Aspect commercial measurement and control, the general-purpose simulation amounts such as temperature, pressure, flow, heat extensively adopt platinum resistance to measure and 4～20mA current signal form is transmitted.Industrially generally need to measure all kinds of non-electric physical quantitys, such as temperature, pressure, speed, flow etc., all need to convert to analog electric signal and just can be transferred on hundreds of the rice outer pulpit or display device, this equipment that converts physical quantity to electric signal is called transmitter.At present some analog quantity transformation devices commonly used generally only have platinum resistance temperature survey or 4～20mA analog current measurement function, rarely compatible platinum resistance temperature survey and 4～20mA analog current composite measurement, and can carry out according to user's request novel platinum resistance and the analog current transmission circuit of flexible channel selecting.Although present a lot of analog quantity transformation devices are measured way and can be selected according to application demand, but generally do not adopt modular mode, the user is difficult to the analog quantity transformation device is integrated in the circuit or cabinet of oneself, can only use external cabinet mode, it not is very convenient using, and expensive, cost performance is lower.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, a kind of platinum resistance and analog current transmission circuit are provided.A kind of platinum resistance that the present invention relates to and analog current transmission circuit can be 0～3.3V linear voltage and 4～20mA linear current with the platinum resistance temperature inversion, and 4～20mA analog current is converted into 0～3.3V linear voltage and 4～20mA electric current loop goes out, transmission circuit employing 5V, 12V ,-the 12V power supply, one line control interface State selective measurements passage.
The present invention includes platinum resistance metering circuit, analog current metering circuit, measurement channel selection circuit, voltage-current converter circuit, magnitude of voltage output interface, current value output interface, measure channel selecting interface and multiple feed interface.
Described platinum resistance metering circuit comprises that the first chip IC 1, the second chip IC 2, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the 9th resistance R 9, the tenth resistance R 10, the 11 resistance R 11, the 12 resistance R 12 form; The first chip IC 1 is one and can regulates the reference source chip, and 6 pin of the first chip IC 1 are connected with ground, and 1 pin of the first chip IC 1,8 pin are connected with an end of the first resistance R 1, an end of the 3rd resistance R 3, an end of the 4th resistance R 4; The other end of the first resistance R 1 is connected with an end of the second resistance R 2, the variable resistor end of the second resistance R 2, an end of the 5th resistance R 5; The other end of the 3rd resistance R 3 is connected with 5V external power source VCC5; The other end of the 4th resistance R 4 is connected with an end of platinum resistance input end PT100, the 6th resistance R 6; The other end of the 5th resistance R 5 is connected with 6 pin of the second chip IC 2, an end of the 8th resistance R 8; The other end of the 6th resistance R 6 is connected with 5 pin of the second chip IC 2, an end of the 7th resistance R 7; The other end grounding connection of the 7th resistance R 7; The other end of the 8th resistance R 8 is connected with 7 pin of the second chip IC 2, an end of the 9th resistance R 9; The other end of the 9th resistance R 9 is connected with 3 pin of the second chip IC 2; One end of the tenth resistance R 10 is connected with 2 pin of the second chip IC 2, an end of the 11 resistance R 11; The other end of the 11 resistance R 11 is connected with an end of the 12 resistance R 12; The other end of the 12 resistance R 12 is connected with 1 pin of the second chip IC 2, output platinum resistance changing voltage V1; 4 pin of the second chip IC 2 are connected with-12V external power source VDD12; 8 pin of the second chip IC 2 are connected with 12V external power source VCC12; 2 pin of the first chip IC 1,3 pin, 4 pin, 5 pin and 7 pin are unsettled.
Described analog current metering circuit comprises that the 3rd chip IC 3, the 13 resistance R 13, the 14 resistance R 14, the 15 resistance R 15, the 16 resistance R 16, the 17 resistance R 17, the 18 resistance R 18, the 19 resistance R 19, the 20 resistance R 20, schottky diode D1 form; The negative pole of schottky diode D1 is connected with an end of 5V external power source VCC5, the 14 resistance R 14; The positive pole of schottky diode D1 is connected with an end of the 13 resistance R 13 and ground connection; The other end of the 13 resistance R 13 is connected with an end of analog current input end IIN, the 17 resistance R 17; The other end grounding connection of the 14 resistance R 14, the variable resistor end of the 14 resistance R 14 is connected with an end of the 15 resistance R 15; The other end of the 15 resistance R 15 is connected with 2 pin of the 3rd chip IC 3, an end of the 16 resistance R 16, an end of the 18 resistance R 18; The other end grounding connection of the 16 resistance R 16; The other end of the 17 resistance R 17 is connected with 3 pin of the 3rd chip IC 3; 8 pin of the 3rd chip IC 3 are connected with 12V external power source VCC12, and 4 pin are connected with-12V external power source VDD12, and 1 pin is connected with an end of the 20 resistance R 20; The other end of the 18 resistance R 18 is connected with an end of the 19 resistance R 19, and the other end of the 19 resistance R 19 is connected with the other end of the 20 resistance R 20, output analog current changing voltage V2.
Described measurement channel selection circuit comprises four-core sheet IC4 and the 5th chip IC 5; 1 pin of four-core sheet IC4 is connected with platinum resistance changing voltage V1,4 pin be connected with analog current changing voltage V2,2 pin and 3 pin link together as output changing voltage VOUT, 7 pin ground connection, 14 pin are connected with 5V external power source VCC5,5 pin are connected with reverse control CB, and 13 pin are connected with external control end Control, and 6 pin, 8 pin, 9 pin, 10 pin, 11 pin and 12 pin are unsettled; 7 pin ground connection of the 5th chip IC 5,14 pin are connected with 5V external power source VCC5, and 2 pin are connected with reverse control CB, and 1 pin is connected with external control end Control, and 3 pin, 4 pin, 5 pin, 6 pin, 8 pin, 9 pin, 10 pin, 11 pin, 12 pin and 13 pin are unsettled.
Described voltage-current converter circuit comprises the 6th chip IC 6, the 21 resistance R 21, the 22 resistance R 22, the 23 resistance R 23, the 24 resistance R 24, the 25 resistance R 25, the 26 resistance R 26, the 27 resistance R 27, the 28 resistance R 28, the 29 resistance R 29, the 30 resistance R 30, the 31 resistance R 31, the 32 resistance R 32, the 33 resistance R 33, the 34 resistance R 34, the 35 resistance R 35, the 36 resistance R 36, the 37 resistance R 37, the 38 resistance R 38, the 39 resistance R 39, the 40 resistance R 40, the first field effect transistor T1, the second field effect transistor T2 forms; 12V external power source VCC12 is connected with an end of the 21 resistance R 21, an end of the 24 resistance R 24, an end of the 33 resistance R 33, an end of the 38 resistance R 38, an end of the 39 resistance R 39 respectively; The other end of the 38 resistance R 38 is connected with 7 pin of the 6th chip IC 6, the grid of the second field effect transistor T2; The other end of the 39 resistance R 39 is connected with the drain electrode of the second field effect transistor T2, an end of the 35 resistance R 35; The other end of the 21 resistance R 21 is connected with an end of the 22 resistance R 22, and the other end of the 22 resistance R 22 is connected with an end of the 23 resistance R 23,2 pin of the 6th chip IC 6; The other end of the 23 resistance R 23 is connected with an end of the 26 resistance R 26, the other end of the 26 resistance R 26 is connected with an end of the 27 resistance R 27, the other end of the 27 resistance R 27 is connected with an end of the 28 resistance R 28, and the other end of the 28 resistance R 28 is connected with the source electrode of the first field effect transistor T1, an end of the 30 resistance R 30; The other end of the 30 resistance R 30 is connected with an end of the 31 resistance R 31, the other end of the 31 resistance R 31 is connected with an end of the 32 resistance R 32, and the other end of the 32 resistance R 32 is connected and grounding connection with an end of the 37 resistance R 37, an end of the 36 resistance R 36; The other end of the 24 resistance R 24 is connected with an end of the 25 resistance R 25,3 pin of the 6th chip IC 6, and the other end of the 25 resistance R 25 is connected with output changing voltage VOUT; 8 pin of the 6th chip IC 6 are connected with 12V external power source VCC12, and 4 pin are connected with-12V external power source VDD12, and 1 pin is connected with an end of the 29 resistance R 29, the grid of the first field effect transistor T1; The other end ground connection of the 29 resistance R 29; The other end of the 33 resistance R 33 is connected with an end of the 34 resistance R 34, the drain electrode of the first field effect transistor T1, and the other end of the 34 resistance R 34 is connected with 5 pin of the other end of the 36 resistance R 36 with the 6th chip IC 6; The other end of the 35 resistance R 35 is connected with 6 pin of the other end of the 37 resistance R 37 with the 6th chip IC 6; The source electrode of the second field effect transistor T2 is connected with an end of the 40 resistance R 40, and the other end of the 40 resistance R 40 is as output switching current IOUT.
Described magnitude of voltage output interface, current value output interface, measurement channel selecting interface and multiple feed interface are selected first row pin P1 and second row pin P2; 1 pin of first row pin P1 is connected with 5V external power source VCC5, and 3 pin ground connection GND connect, and 5 pin are connected with analog current input end IIN, and 7 pin are connected with platinum resistance input end PT100, and 9 pin are connected with external control end Control; 2 pin of second row pin P2 are connected with 12V external power source VCC12, and 4 pin are connected with-12V external power source VDD12, and 6 pin are connected with output switching current IOUT, and 8 pin ground connection GND connect, 10 pin with export changing voltage VOUT and be connected; The magnitude of voltage output interface comprises output changing voltage VOUT and ground GND, the current value output interface comprises output switching current IOUT and ground GND, measure the channel selecting interface and comprise external control end Control and ground GND, the multiple feed interface comprise 5V external power source VCC5,12V external power source VCC12 ,-12V external power source VDD12 and ground GND.
The first chip IC 1 among the present invention, the second chip IC 2, the 3rd chip IC 3, schottky diode D1, four-core sheet IC4, the 5th chip IC 5, the 6th chip IC 6, the first field effect transistor T1, the second field effect transistor T2 all adopt matured product; The first chip IC 1 adopts the TL431 of Texas Instruments for can regulate the reference source chip; The second chip IC 2 is operational amplifier, adopts the LM358D of ST semiconductor company; The 3rd chip IC 3 is operational amplifier, adopts the LM358D of ST semiconductor company; Schottky diode D1 adopts the 1N4733A of FAIRCHILD company; Four-core sheet IC4 is analog switch chip, adopts the CD4066 of INTERSL company; The 5th chip IC 5 is the reverser chip, adopts the 74HC04 of National Semiconductor; The first field effect transistor T1 adopts the IRF540 of ST company, and the second field effect transistor T2 adopts the IRF9540 of ST company; The 6th chip IC 6 is operational amplifier, adopts the LM358D of ST semiconductor company.
Compare with background technology, the comprehensive platinum resistance temperature survey of the present invention and 4～20mA analog current measurement capability, and can measure flexibly channel selecting according to user's request, has precision high, volume is little, modularization, cost is low, the stability high, very easy to use, only need seldom outer member, directly just circuit module of the present invention can be embedded in the real system, realize that the platinum resistance temperature signal is converted to normal voltage and current signal, 4～20mA analog current is converted to standard voltage signal and encircles out signal, can be widely used in the temperature of field of industrial production, pressure, flow, the usual amounts such as heat are measured.
Description of drawings
Fig. 1 is structural representation of the present invention;
Fig. 2 is the platinum resistance metering circuit structural representation among Fig. 1;
Fig. 3 is the analog current metering circuit structural representation among Fig. 1;
Fig. 4 is the measurement channel selection circuit structural representation among Fig. 1;
Fig. 5 is the voltage-current converter circuit structural representation among Fig. 1;
Fig. 6 is magnitude of voltage output interface, current value output interface, measurement channel selecting interface and the dual power supply interface structure schematic diagram among Fig. 1;
Fig. 7 is the temperature survey of the first platinum resistance and theoretical value comparative result figure;
Fig. 8 is the temperature survey of the second platinum resistance and theoretical value comparative result figure;
Fig. 9 is that the first 4-20mA analog current is measured and theoretical value comparative result figure;
Figure 10 is that the second 4-20mA analog current is measured and theoretical value comparative result figure.
Embodiment
The invention will be further described below in conjunction with accompanying drawing.
As shown in Figure 1, the present invention mainly is comprised of platinum resistance metering circuit 1, analog current metering circuit 2, measurement channel selection circuit 3, voltage-current converter circuit 4, magnitude of voltage output interface 6, current value output interface 5, measurement channel selecting interface 7 and multiple feed interface 8.Analog current metering circuit, platinum resistance metering circuit, measurement channel selection circuit, voltage-current converter circuit are core of the present invention, magnitude of voltage output interface, current value output interface, measurement channel selecting interface and multiple feed interface are the peripheral interface part, mainly are made of some connectors.
As shown in Figure 2, described platinum resistance metering circuit utilizes platinum resistance that temperature signal is converted into the resistance signal, the recycling steady current passes through platinum resistance, the resistance signal is converted into voltage signal, mainly comprises the first chip IC 1, the second chip IC 2, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the 9th resistance R 9, the tenth resistance R 10, the 11 resistance R 11, the 12 resistance R 12.The resistance of the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the 9th resistance R 9, the tenth resistance R 10, the 11 resistance R 11, the 12 resistance R 12 is respectively 1K, 200,100,1K, 10K, 10K, 100K, 100K, 10K, 10K, 30K, 5K.The first chip IC 1 adopts the regulated reference source chip TL431 of Texas Instruments, and TL431 is the three end adjustable shunt reference sources that the good thermal stability energy is arranged.6 pin ground connection of the first chip IC 1,1 pin, 8 pin are connected with the first resistance R 1, the 3rd resistance R 3, the 4th resistance R 4, and the other end that the first resistance R 1, the 3rd resistance R 3, the 4th resistance R 4 connect is connected with a stiff end, 5V external power source VCC5, the platinum resistance input end PT100 of the second resistance R 2 respectively.The first chip IC 1 has consisted of a constant-current source circuit in conjunction with peripheral resistance, is 2.27mA according to can be calculated current value.Another stiff end of the second resistance R 2 is connected with ground, and the adjustable end of the second resistance R 2 is connected with an end of the 5th resistance R 5, and the other end of the 5th resistance R 5 is connected with 6 pin of the second chip IC 2; Platinum resistance input end PT100 is connected with an end of the 6th resistance R 6, and the other end of the 6th resistance R 6 is connected with 5 pin of the second chip IC 2 and an end of the 7th resistance R 7, and the other end of the 7th resistance R 7 is connected with ground.Transform the very little difficult detection of voltage signal values of coming by constant-current source circuit, the present invention produces the differential voltage signal that amplifies by differential amplifier.The second chip IC 2 is the operational amplifier LM358D of ST semiconductor company, LM358 inside include two independently, the dual operational amplifier of high-gain, internal frequency compensation, the present invention adopts positive and negative 12V dual power supply mode, 8 pin are connected with 12V external power source VCC12,4 pin are connected with-12V external power source VDD12,6 pin are connected with an end of the 8th resistance R 8, and the other end of the 8th resistance R 8 is connected with 7 pin of the second chip IC 2; 7 pin of the second chip IC 2 are connected with an end of the 9th resistance R 9, and the other end of the 9th resistance R 9 is connected with 3 pin of the second chip IC 2; 2 pin of the second chip IC 2 are connected with an end of the tenth resistance R 10 and the 11 resistance R 11, the other end of the tenth resistance R 10 is connected with ground, the other end of the 11 resistance R 11 is connected with an end of the 12 resistance R 12, the other end of the 12 resistance R 12 is connected with 1 pin of the second chip IC 2, is platinum resistance changing voltage V1.The A part IC2-A of the second chip IC 2 consists of difference channel, and the B part IC2-B of the second chip IC 2 consists of negative feedback amplifier circuit.
As shown in Figure 3, described analog current metering circuit is converted to magnitude of voltage by resistance with analog current, then carry out voltage amplification by negative feedback amplifier circuit, mainly comprise the 3rd chip IC 3, the 13 resistance R 13, the 14 resistance R 14, the 15 resistance R 15, the 16 resistance R 16, the 17 resistance R 17, the 18 resistance R 18, the 19 resistance R 19, the 20 resistance R 20, schottky diode D1.The resistance of the 13 resistance R 13, the 14 resistance R 14, the 15 resistance R 15, the 16 resistance R 16, the 17 resistance R 17, the 18 resistance R 18, the 19 resistance R 19, the 20 resistance R 20 is respectively 100,1K, 100K, 100K, 1K, 50K, 3K, 1K ohm.Schottky diode D1 adopts the 1N4733A of FAIRCHILD company, shields, and negative pole connects 5V external power source VCC5, an anodal end that connects ground and the 13 resistance R 13, the other end connecting analog current input terminal IIN of the 13 resistance R 13.A stiff end of the 14 resistance R 14 connects 5V external power source VCC5, and another stiff end connects ground, and adjustable end connects an end of the 15 resistance R 15; The other end of the 15 resistance R 15 connects 2 pin of the 3rd chip IC 3 and an end of the 16 resistance R 16, and the other end of the 16 resistance R 16 is connected with ground; One end of the 17 resistance R 17 is connected with 5V external power source VCC5, and the other end is connected with 3 pin of the 3rd chip IC 3.The 3rd chip IC 3 adopts the operational amplifier LM358D of ST semiconductor company, the present invention adopts positive and negative 12V dual power supply mode, 8 pin are connected with 12V external power source VCC12,4 pin are connected with-12V external power source VDD12,2 pin are connected with an end of the 18 resistance R 18, the other end of the 18 resistance R 18 is connected with an end of the 19 resistance R 19, and the other end of the 19 resistance R 19 is connected with analog current changing voltage V2; 1 pin of the 3rd chip IC 3 is connected with an end of the 20 resistance R 20, and the other end of the 20 resistance R 20 and analog current changing voltage V2 have consisted of a negative-feedback amplifier.
As shown in Figure 4, described measurement channel selection circuit comprises that four-core sheet IC4 and the 5th chip IC 5, the four-core sheet IC4 are analog switch chip, adopts the CD4066 of INTERSL company; The 5th chip IC 5 is the reverser chip, adopts the 74HC04 of National Semiconductor.1 pin of four-core sheet IC4 with are connected pin and are connected with analog current changing voltage V2 with platinum resistance changing voltage V1 respectively, 2 pin and 3 pin link together as output changing voltage VOUT, 7 pin ground connection, and 14 pin meet 5V external power source VCC5,5 pin meet reverse control CB, and 13 pin meet external control end Control; 7 pin ground connection of the 5th chip IC 5,14 pin meet 5V external power source VCC5, and 2 pin meet reverse control CB, and 1 pin meets external control end Control, and all the other pins of four-core sheet IC4 and the 5th chip IC 5 are unsettled.When external control end Control was 5V, by reverser chip IC 5, oppositely controlling CB was 0V, otherwise when external control end Control was 0V, by reverser chip IC 5, oppositely controlling CB was 5V.External control end Control and reverse control CB synergy analog switch chip are so that output changing voltage VOUT switches to platinum resistance changing voltage V1 or analog current changing voltage V2.
As shown in Figure 5, described voltage-current converter circuit is converted to the 4-20mA analog current value by operational amplifier with magnitude of voltage, and calculating output area according to theory is 4.11
20.07mA, mainly comprise the 6th chip IC 6, the 21 resistance R 21, the 22 resistance R 22, the 23 resistance R 23, the 24 resistance R 24, the 25 resistance R 25, the 26 resistance R 26, the 27 resistance R 27, the 28 resistance R 28, the 29 resistance R 29, the 30 resistance R 30, the 31 resistance R 31, the 32 resistance R 32, the 33 resistance R 33, the 34 resistance R 34, the 35 resistance R 35, the 36 resistance R 36, the 37 resistance R 37, the 38 resistance R 38, the 39 resistance R 39, the 40 resistance R 40, the first field effect transistor T1, the second field effect transistor T2.The 21 resistance R 21, the 22 resistance R 22, the 23 resistance R 23, the 24 resistance R 24, the 25 resistance R 25, the 26 resistance R 26, the 27 resistance R 27, the 28 resistance R 28, the 29 resistance R 29, the 30 resistance R 30, the 31 resistance R 31, the 32 resistance R 32, the 33 resistance R 33, the 34 resistance R 34, the 35 resistance R 35, the 36 resistance R 36, the 37 resistance R 37, the 38 resistance R 38, the 39 resistance R 39, the 40 resistance R 40 is respectively 100K, 100K, 51K, 1M, 1M, 22K, 500,100K, 1K, 100,75,18,100,10K, 10K, 51K, 51K, 1K, 100,100 ohm.The first field effect transistor T1 adopts the IRF540 of ST company, and the second field effect transistor T2 adopts the IRF9540 of ST company.12V external power source VCC12 is connected with an end of the 21 resistance R 21, the 24 resistance R 24, the 33 resistance R 33, the 38 resistance R 38, the 39 resistance R 39 respectively, the other end of the 38 resistance R 38 is connected with 7 pin of the 6th chip IC 6, and the other end of the 39 resistance R 39 is connected with the drain electrode of the second field effect transistor T2; The other end of the 21 resistance R 21 is connected with an end of the 22 resistance R 22, and the other end of the 22 resistance R 22 is connected with an end of the 23 resistance R 23 and 2 pin of the 6th chip IC 6; The other end of the 23 resistance R 23 is connected with an end of the 26 resistance R 26, the other end of the 26 resistance R 26 is connected with an end of the 27 resistance R 27, the other end of the 27 resistance R 27 is connected with an end of the 28 resistance R 28, the other end of the 28 resistance R 28 is connected with the source electrode of the first field effect transistor T1 and an end of the 30 resistance R 30, the other end of the 30 resistance R 30 is connected with an end of the 31 resistance R 31, the other end of the 31 resistance R 31 is connected with an end of the 32 resistance R 32, and the other end of the 32 resistance R 32 is connected with ground; The other end of the 24 resistance R 24 is connected with an end of the 25 resistance R 25 and 3 pin of the 6th chip IC 6, and the other end of the 25 resistance R 25 is connected with output changing voltage VOUT.The 6th chip IC 6 is operational amplifier, adopt the LM358D of ST semiconductor company, the present invention adopts positive and negative 12V dual power supply mode, 8 pin are connected with 12V external power source VCC12,4 pin are connected with-12V external power source VDD12, one end of 1 pin and the 29 resistance R 29 be connected the grid of field effect transistor T1 and be connected, the other end of the 29 resistance R 29 is connected with ground; One end of the other end of the 33 resistance R 33 and the 34 resistance R 34 be connected the drain electrode of field effect transistor T1 and be connected, the other end of the 34 resistance R 34 is connected with an end of the 36 resistance R 36 and 5 pin of the 6th chip IC 6, and the other end of the 36 resistance R 36 is connected with ground; The other end of the 39 resistance R 39 is connected with an end of the 35 resistance R 35, and the other end of the 35 resistance R 35 is connected with an end of the 37 resistance R 37 and 6 pin of the 6th chip IC 6, and the other end of the 37 resistance R 37 is connected with ground; 7 pin of the 6th chip IC 6 are connected with the grid of the second field effect transistor T2, and the source electrode of the second field effect transistor T2 is connected with an end of the 40 resistance R 40, and the other end of the 40 resistance R 40 is as output switching current IOUT.
As shown in Figure 6, described magnitude of voltage output interface, current value output interface, measurement channel selecting interface and multiple feed interface are first row pin P1 and second row pin P2.The 1st, 3,5,7,9 pin of first row pin P1 be respectively 5V external power source VCC5, GND, analog current input end IIN, platinum resistance input end PT100 and external control end Control, the 2nd, 4,6,8,10 pin of second row pin P2 be respectively 12V external power source VCC12 connect ,-12V external power source VDD12, output switching current IOUT, GND and output changing voltage VOUT.The magnitude of voltage output interface comprises output changing voltage VOUT and ground GND, the current value output interface comprises output switching current IOUT and ground GND, measure the channel selecting interface and comprise external control end Control and ground GND, the dual power supply interface comprise 5V external power source VCC5,12V external power source VCC12 connect ,-12V external power source VDD12 and ground GND.
Platinum resistance temperature survey and theoretical value comparative result in platinum resistance of the present invention and the analog current transmission circuit (being converted into 0-3.3V linear voltage and 4-20mA linear current) as shown in Figure 7 and Figure 8, error amount satisfies 3% requirement.
The 4-20mA analog current measures that as shown in Figure 9 and Figure 10, error amount satisfies 3% requirement with theoretical value comparative result (be converted into the 0-3.3V linear voltage and the 4-20mA electric current loop goes out) in platinum resistance of the present invention and the analog current transmission circuit.
The concrete technical indicator of the present embodiment is as follows:
(1) analog current scope: 4～20mA;
(2) temperature measurement range: 0～100 ℃;
(3) output voltage range: 0～3.3V;
(4) encircle out range of current: 4～20mA;
(5) analog current is measured way: the 1 tunnel;
(6) platinum resistor temperature measuring way: 1 tunnel;
(7) measuring error :≤3%.
Claims (1)
1. platinum resistance and analog current transmission circuit, comprise platinum resistance metering circuit, analog current metering circuit, measurement channel selection circuit, voltage-current converter circuit, magnitude of voltage output interface, current value output interface, measure channel selecting interface and multiple feed interface, it is characterized in that:
Described platinum resistance metering circuit comprises that the first chip IC 1, the second chip IC 2, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the 9th resistance R 9, the tenth resistance R 10, the 11 resistance R 11, the 12 resistance R 12 form; The first chip IC 1 is one and can regulates the reference source chip, and 6 pin of the first chip IC 1 are connected with ground, and 1 pin of the first chip IC 1,8 pin are connected with an end of the first resistance R 1, an end of the 3rd resistance R 3, an end of the 4th resistance R 4; The other end of the first resistance R 1 is connected with an end of the second resistance R 2, the variable resistor end of the second resistance R 2, an end of the 5th resistance R 5; The other end of the 3rd resistance R 3 is connected with 5V external power source VCC5; The other end of the 4th resistance R 4 is connected with an end of platinum resistance input end PT100, the 6th resistance R 6; The other end of the 5th resistance R 5 is connected with 6 pin of the second chip IC 2, an end of the 8th resistance R 8; The other end of the 6th resistance R 6 is connected with 5 pin of the second chip IC 2, an end of the 7th resistance R 7; The other end grounding connection of the 7th resistance R 7; The other end of the 8th resistance R 8 is connected with 7 pin of the second chip IC 2, an end of the 9th resistance R 9; The other end of the 9th resistance R 9 is connected with 3 pin of the second chip IC 2; One end of the tenth resistance R 10 is connected with 2 pin of the second chip IC 2, an end of the 11 resistance R 11; The other end of the 11 resistance R 11 is connected with an end of the 12 resistance R 12; The other end of the 12 resistance R 12 is connected with 1 pin of the second chip IC 2, output platinum resistance changing voltage V1; 4 pin of the second chip IC 2 are connected with-12V external power source VDD12; 8 pin of the second chip IC 2 are connected with 12V external power source VCC12; 2 pin of the first chip IC 1,3 pin, 4 pin, 5 pin and 7 pin are unsettled; Described analog current metering circuit comprises that the 3rd chip IC 3, the 13 resistance R 13, the 14 resistance R 14, the 15 resistance R 15, the 16 resistance R 16, the 17 resistance R 17, the 18 resistance R 18, the 19 resistance R 19, the 20 resistance R 20, schottky diode D1 form; The negative pole of schottky diode D1 is connected with an end of 5V external power source VCC5, the 14 resistance R 14; The positive pole of schottky diode D1 is connected with an end of the 13 resistance R 13 and ground connection; The other end of the 13 resistance R 13 is connected with an end of analog current input end IIN, the 17 resistance R 17; The other end grounding connection of the 14 resistance R 14, the variable resistor end of the 14 resistance R 14 is connected with an end of the 15 resistance R 15; The other end of the 15 resistance R 15 is connected with 2 pin of the 3rd chip IC 3, an end of the 16 resistance R 16, an end of the 18 resistance R 18; The other end grounding connection of the 16 resistance R 16; The other end of the 17 resistance R 17 is connected with 3 pin of the 3rd chip IC 3; 8 pin of the 3rd chip IC 3 are connected with 12V external power source VCC12, and 4 pin are connected with-12V external power source VDD12, and 1 pin is connected with an end of the 20 resistance R 20; The other end of the 18 resistance R 18 is connected with an end of the 19 resistance R 19, and the other end of the 19 resistance R 19 is connected with the other end of the 20 resistance R 20, output analog current changing voltage V2;
Described measurement channel selection circuit comprises four-core sheet IC4 and the 5th chip IC 5; 1 pin of four-core sheet IC4 is connected with platinum resistance changing voltage V1,4 pin be connected with analog current changing voltage V2,2 pin and 3 pin link together as output changing voltage VOUT, 7 pin ground connection, 14 pin are connected with 5V external power source VCC5,5 pin are connected with reverse control CB, and 13 pin are connected with external control end Control, and 6 pin, 8 pin, 9 pin, 10 pin, 11 pin and 12 pin are unsettled; 7 pin ground connection of the 5th chip IC 5,14 pin are connected with 5V external power source VCC5, and 2 pin are connected with reverse control CB, and 1 pin is connected with external control end Control, and 3 pin, 4 pin, 5 pin, 6 pin, 8 pin, 9 pin, 10 pin, 11 pin, 12 pin and 13 pin are unsettled;
Described voltage-current converter circuit comprises the 6th chip IC 6, the 21 resistance R 21, the 22 resistance R 22, the 23 resistance R 23, the 24 resistance R 24, the 25 resistance R 25, the 26 resistance R 26, the 27 resistance R 27, the 28 resistance R 28, the 29 resistance R 29, the 30 resistance R 30, the 31 resistance R 31, the 32 resistance R 32, the 33 resistance R 33, the 34 resistance R 34, the 35 resistance R 35, the 36 resistance R 36, the 37 resistance R 37, the 38 resistance R 38, the 39 resistance R 39, the 40 resistance R 40, the first field effect transistor T1, the second field effect transistor T2 forms; 12V external power source VCC12 is connected with an end of the 21 resistance R 21, an end of the 24 resistance R 24, an end of the 33 resistance R 33, an end of the 38 resistance R 38, an end of the 39 resistance R 39 respectively; The other end of the 38 resistance R 38 is connected with 7 pin of the 6th chip IC 6, the grid of the second field effect transistor T2; The other end of the 39 resistance R 39 is connected with the drain electrode of the second field effect transistor T2, an end of the 35 resistance R 35; The other end of the 21 resistance R 21 is connected with an end of the 22 resistance R 22, and the other end of the 22 resistance R 22 is connected with an end of the 23 resistance R 23,2 pin of the 6th chip IC 6; The other end of the 23 resistance R 23 is connected with an end of the 26 resistance R 26, the other end of the 26 resistance R 26 is connected with an end of the 27 resistance R 27, the other end of the 27 resistance R 27 is connected with an end of the 28 resistance R 28, and the other end of the 28 resistance R 28 is connected with the source electrode of the first field effect transistor T1, an end of the 30 resistance R 30; The other end of the 30 resistance R 30 is connected with an end of the 31 resistance R 31, the other end of the 31 resistance R 31 is connected with an end of the 32 resistance R 32, and the other end of the 32 resistance R 32 is connected and grounding connection with an end of the 37 resistance R 37, an end of the 36 resistance R 36; The other end of the 24 resistance R 24 is connected with an end of the 25 resistance R 25,3 pin of the 6th chip IC 6, and the other end of the 25 resistance R 25 is connected with output changing voltage VOUT; 8 pin of the 6th chip IC 6 are connected with 12V external power source VCC12, and 4 pin are connected with-12V external power source VDD12, and 1 pin is connected with an end of the 29 resistance R 29, the grid of the first field effect transistor T1; The other end ground connection of the 29 resistance R 29; The other end of the 33 resistance R 33 is connected with an end of the 34 resistance R 34, the drain electrode of the first field effect transistor T1, and the other end of the 34 resistance R 34 is connected with 5 pin of the other end of the 36 resistance R 36 with the 6th chip IC 6; The other end of the 35 resistance R 35 is connected with 6 pin of the other end of the 37 resistance R 37 with the 6th chip IC 6; The source electrode of the second field effect transistor T2 is connected with an end of the 40 resistance R 40, and the other end of the 40 resistance R 40 is as output switching current IOUT;
Described magnitude of voltage output interface, current value output interface, measurement channel selecting interface and multiple feed interface are selected first row pin P1 and second row pin P2; 1 pin of first row pin P1 is connected with 5V external power source VCC5, and 3 pin ground connection GND connect, and 5 pin are connected with analog current input end IIN, and 7 pin are connected with platinum resistance input end PT100, and 9 pin are connected with external control end Control; 2 pin of second row pin P2 are connected with 12V external power source VCC12, and 4 pin are connected with-12V external power source VDD12, and 6 pin are connected with output switching current IOUT, and 8 pin ground connection GND connect, 10 pin with export changing voltage VOUT and be connected; The magnitude of voltage output interface comprises output changing voltage VOUT and ground GND, the current value output interface comprises output switching current IOUT and ground GND, measure the channel selecting interface and comprise external control end Control and ground GND, the multiple feed interface comprise 5V external power source VCC5,12V external power source VCC12 ,-12V external power source VDD12 and ground GND;
Described the first chip IC 1 adopts the TL431 of Texas Instruments for can regulate the reference source chip; The second chip IC 2 is operational amplifier, adopts the LM358D of ST semiconductor company; The 3rd chip IC 3 is operational amplifier, adopts the LM358D of ST semiconductor company; Schottky diode D1 adopts the 1N4733A of FAIRCHILD company; Four-core sheet IC4 is analog switch chip, adopts the CD4066 of INTERSL company; The 5th chip IC 5 is the reverser chip, adopts the 74HC04 of National Semiconductor; The first field effect transistor T1 adopts the IRF540 of ST company, and the second field effect transistor T2 adopts the IRF9540 of ST company; The 6th chip IC 6 is operational amplifier, adopts the LM358D of ST semiconductor company.
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| CN201210346601.9A CN102879018B (en) | 2012-09-18 | 2012-09-18 | Platinum resistance and analogous current transducing circuit |
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| CN201210346601.9A CN102879018B (en) | 2012-09-18 | 2012-09-18 | Platinum resistance and analogous current transducing circuit |
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| CN102879018B CN102879018B (en) | 2014-09-17 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104460806A (en) * | 2014-12-25 | 2015-03-25 | 李钢 | Voltage and current signal conversion circuit |
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| CN104460806A (en) * | 2014-12-25 | 2015-03-25 | 李钢 | Voltage and current signal conversion circuit |
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