阅读说明：本技术 一种mV信号测量温度补偿装置 (A kind of mV signal measurement temperature compensation means ) 是由 赵俊奎 于 2018-05-24 设计创作，主要内容包括：本发明提供一种mV信号测量温度补偿装置,该补偿装置包括用于对热电偶的输出电压进行放大的仪表放大器I、用于对一次传感器输出电压进行放大的仪表放大器II、比较器电路、偏置选择调整电路、比例系数选择调整电路、加法器I和加法器II；所述比较器电路对仪表放大器I的输出信号进行比较处理后输出信号S0和信号S1,所述信号S0和信号S1分别作为比例系数选择调整电路和偏置选择调整电路的输入信号；所述偏置选择调电路的输出与比例系数选择调整电路的输出作为加法器I的输入,所述加法器I的输出与仪表放大器II的输出作为加法器II的输入。(The present invention provides a kind of mV signal measurement temperature compensation means, which includes the instrument amplifier I amplified for the output voltage to thermocouple, the instrument amplifier II for amplifying to primary transducer output voltage, comparator circuit, biasing selection adjustment circuit, proportionality coefficient selection adjustment circuit, adder I and adder II；The comparator circuit is compared after processing output signal S0 and signal S1, the signal S0 and signal S1 respectively as the input signal of proportionality coefficient selection adjustment circuit and biasing selection adjustment circuit to the output signal of instrument amplifier I；The biasing selects input of the output for adjusting the output of circuit and proportionality coefficient to select adjustment circuit as adder I, the input of the output of the adder I and the output of instrument amplifier II as adder II.)

1. a kind of mV signal measurement temperature compensation means, which is characterized in that the compensation device includes for the output to thermocouple The instrument amplifier I that voltage amplifies, the instrument amplifier II for being amplified to primary transducer output voltage, compare Device circuit, biasing selection adjustment circuit, proportionality coefficient selection adjustment circuit, adder I and adder II；The comparator circuit Output signal S0 and signal S1, the signal S0 and signal S1 after handling is compared to the output signal of instrument amplifier I to divide Input signal not as proportionality coefficient selection adjustment circuit and biasing selection adjustment circuit；The defeated of circuit is adjusted in the biasing selection Input of the output of adjustment circuit as adder I, the output of the adder I and instrument amplifier are selected with proportionality coefficient out Input of the output of II as adder II.

2. a kind of mV signal measurement temperature compensation means according to claim 1, which is characterized in that the comparator circuit Tool is there are two comparing threshold value, wherein first compares threshold value and compare threshold value less than second；

When the input voltage of comparator circuit compares threshold value less than first, the signal S0 and signal S1 are low level simultaneously；

When the input voltage size first of comparator circuit compares threshold value and compares threshold value less than second simultaneously, the signal S0 is High level, the signal S1 are low level；

When the input voltage of comparator circuit, which is greater than second, compares threshold value, the signal S0 and signal S1 are high level simultaneously.

3. a kind of mV signal measurement temperature compensation means according to claim 1, which is characterized in that the comparator circuit Including the first amplifier U1A and the second amplifier U1B, the first amplifier U1A output signal S0, the second amplifier U1B output signal S1；It is described Parallel resistance R1 between the output end and positive input terminal of first amplifier U1A, the positive input of the first amplifier U1A connect through resistance R2 The output end of instrument amplifier I is connect, the reverse input end of the first amplifier U1A is connect with first threshold comparison voltage end；Institute Parallel resistance R6 between the output end and positive input of the second amplifier is stated, the positive input of the first amplifier U1A is through resistance R5 The output end of instrument amplifier I is connected, the reverse input end of the second amplifier U1B is connect with second threshold comparison voltage end.

4. a kind of mV signal measurement temperature compensation means according to claim 3, which is characterized in that the first threshold ratio It include the resistance R3 and resistance R4 being connected in series compared with voltage end, resistance R3 connects reference voltage, resistance R4 ground connection, resistance R3 and resistance The connecting pin of R4 is connect with the reverse input end of the first amplifier U1A.

5. a kind of mV signal measurement temperature compensation means according to claim 3 or 4, which is characterized in that second threshold Value comparison voltage end includes the resistance R7 and resistance R8 being connected in series, and resistance R7 connects reference voltage, resistance R8 ground connection, resistance R7 with The connecting pin of resistance R8 is connect with the reverse input end of the second amplifier U1B.

6. a kind of mV signal measurement temperature compensation means according to claim 1, which is characterized in that the instrument amplifier II includes the amplification module I and reference voltage output module of an adjustable gain, an adjustable voltage input to reference voltage output Module, the reference end of the output end connection amplification module I of reference voltage output module.

7. a kind of mV signal measurement temperature compensation means according to claim 6, which is characterized in that the instrument amplifier II further includes a filter circuit connecting with the power end of amplification module I.

8. a kind of mV signal measurement temperature compensation means according to claim 7, which is characterized in that the filter circuit is Low-pass filter.

9. a kind of mV signal measurement temperature compensation means according to claim 2 or 3, which is characterized in that the ratio system Number selection adjustment circuit includes an a gating module I and amplification module II；Gating module I is by signal S0 and signal S1 as defeated Enter and control signal, output end is connected to the controlled end of amplification module II, and the output end of the instrument amplifier II connects amplification The input terminal of module ii；The channel that gating module I is controlled by signal S0 and signal S1 further realizes ratio system selection and adjusts The adjusting of whole circuit output voltage.

10. a kind of mV signal measurement temperature compensation means according to claim 9, which is characterized in that the biasing selection Adjustment circuit includes a constant-current source and a gating module II；Gating module II is believed by signal S0 and signal S1 as input control Number, output voltage VB；Realize that biasing selection adjustment circuit is defeated by the channel that signal S0 and signal S1 controls gating module II The adjusting of voltage out.

Technical field

The present invention relates to permanent-magnet electromagnetic field of flow meters, and in particular to a kind of mV signal measurement temperature compensation means.

Background technique

Had according to permanent-magnet electromagnetic flowmeter principle: E=B*L*V (1)

Wherein, E is that primary transducer exports mV signal, and B is permanent magnet magnetic flux density, and L is sodium channel diameter, and V is sodium Flow velocity.Ideally, B and L will not change, and the mV potential and sodium flow velocity of primary transducer output are linear.But In actual condition, since pipe diameter L can expand with heat and contract with cold variation with sodium liquid temperature, B value can increase with temperature and be reduced, and also can It changes over time and changes, secondary meter should compensate non-thread between this output of the mV due to caused by temperature change and flow velocity Property.But since secondary meter is pure analog circuit, it is difficult to realize that multinomial penalty coefficient is set.

Existing millivolt measurement temperature-compensating is typically all to be based on single-chip microcontroller or microprocessor and converter, is sampled simultaneously The mV signal of flow mV signal and temperature；But do not allow in certain fields using microprocessor, or allow using micro- place Reason device still needs related software to authenticate (such as V&V), considerably increases design cycle and cost in this way, therefore the present invention uses Pure hardware realization flow measurement temperature compensation function.

Summary of the invention

In view of the foregoing deficiencies of prior art, the purpose of the present invention is to provide a kind of mV signal measurement temperature-compensatings Device.

In order to achieve the above objects and other related objects, the present invention provides a kind of mV signal measurement temperature compensation means, should Compensation device includes the instrument amplifier I amplified for the output voltage to thermocouple, for exporting to primary transducer Instrument amplifier II that voltage amplifies, comparator circuit, biasing selection adjustment circuit, proportionality coefficient selection adjustment circuit, Adder I and adder II；The comparator circuit to the output signal of instrument amplifier I be compared processing after output signal S0 and signal S1, the signal S0 and signal S1 respectively as proportionality coefficient selection adjustment circuit and bias selection adjustment circuit Input signal；The biasing selects that the output of circuit is adjusted to select the output of adjustment circuit as the defeated of adder I with proportionality coefficient Enter, the input of the output of the adder I and the output of instrument amplifier II as adder II.

Preferably, comparator circuit tool is there are two comparing threshold value, wherein first compares threshold value and compare threshold less than second Value；

When the input voltage of comparator circuit compares threshold value less than first, the signal S0 and signal S1 are low electricity simultaneously It is flat；

When the input voltage size first of comparator circuit compares threshold value and compares threshold value, the signal less than second simultaneously S0 is high level, and the signal S1 is low level；

When the input voltage of comparator circuit, which is greater than second, compares threshold value, the signal S0 and signal S1 are high electricity simultaneously It is flat.

Preferably, the comparator circuit includes the first amplifier U1A and the second amplifier U1B, the first amplifier U1A output signal S0, the second amplifier U1B output signal S1；Parallel resistance R1 between the output end and positive input terminal of the first amplifier U1A, first Output end of the positive input of amplifier U1A through resistance R2 connection instrument amplifier I, the reversed input of the first amplifier U1A End is connect with first threshold comparison voltage end；Parallel resistance R6 between the output end and positive input of second amplifier, the Output end of the positive input of one amplifier U1A through resistance R5 connection instrument amplifier I, the second amplifier U1B's is reversed defeated Enter end to connect with second threshold comparison voltage end.

Preferably, first threshold comparison voltage end includes the resistance R3 and resistance R4 being connected in series, and resistance R3 connects base Quasi- voltage, resistance R4 ground connection, resistance R3 are connect with the connecting pin of resistance R4 with the reverse input end of the first amplifier U1A.

Preferably, second threshold comparison voltage end includes the resistance R7 and resistance R8 being connected in series, and resistance R7 connects base Quasi- voltage, resistance R8 ground connection, resistance R7 are connect with the connecting pin of resistance R8 with the reverse input end of the second amplifier U1B.

Preferably, the instrument amplifier II includes the amplification module I and reference voltage output module of an adjustable gain, and one Adjustable voltage input is to reference voltage output module, the reference of the output end connection amplification module I of reference voltage output module End.

Preferably, the instrument amplifier II further includes a filter circuit connecting with the power end of amplification module I.

Preferably, the filter circuit is low-pass filter.

Preferably, the proportionality coefficient selection adjustment circuit includes an a gating module I and amplification module II；The gating mould For block I by signal S0 and signal S1 as input control signal, output end is connected to the controlled end of amplification module II, the instrument The input terminal of the output end connection amplification module II of amplifier II；The channel of gating module I is controlled by signal S0 and signal S1, Further realize the adjusting of ratio system selection adjustment circuit output voltage.

Preferably, the biasing selection adjustment circuit includes a constant-current source and a gating module II；Gating module II by Signal S0 and signal S1 is as input control signal, output voltage VB；Gating module II is controlled by signal S0 and signal S1 Channel realize biasing selection adjustment circuit output voltage adjusting.

As described above, a kind of mV signal measurement temperature compensation means of the invention, has the advantages that

1, flow signal temperature-compensating is realized using pure hardware circuit mode, is not necessarily to process control, simplify design difficulty, contracting The short sawn timber development cycle；

2, the compensation way anti-interference ability using pure hardware (simulation) mode compared to modulus mixing is asked

3, small using the output delay of hardware compensating mode flow compared to micro process+converter mode.

4, microprocessor+converter mode is compared, it is low in energy consumption using hardware compensating mode.

Detailed description of the invention

Fig. 1 is the principle of the present invention block diagram；

Fig. 2 is the circuit diagram of comparator circuit；

Fig. 3 is the circuit diagram of instrument amplifier II；

Fig. 4 is the circuit diagram that proportionality coefficient selects adjustment circuit；

Fig. 5 is the circuit diagram of biasing selection adjustment circuit.

Specific embodiment

Embodiments of the present invention are illustrated by particular specific embodiment below, those skilled in the art can be by this explanation Content disclosed by book is understood other advantages and efficacy of the present invention easily.

Please refer to Fig. 1~5.It should be clear that this specification structure depicted in this specification institute accompanying drawings, ratio, size etc., only to match The revealed content of specification is closed, so that those skilled in the art understands and reads, is not intended to limit the invention implementable Qualifications, therefore do not have technical essential meaning, the modification of any structure, the change of proportionate relationship or the adjustment of size, In the case where not influencing the effect of present invention can be generated and the purpose that can reach, should all still fall in disclosed technology In the range of appearance can cover.Meanwhile cited such as "upper", "lower", "left", "right", " centre " and " one " in this specification Term, be merely convenient to being illustrated for narration, rather than to limit the scope of the invention, the change of relativeness or Adjustment, under the content of no substantial changes in technology, when being also considered as the enforceable scope of the present invention.

As shown in Figure 1, this implementation provides a kind of mV signal measurement temperature compensation means, which includes for heat Instrument amplifier I that the output voltage of galvanic couple amplifies, the instrument for amplifying to primary transducer output voltage are put Big device II, comparator circuit, biasing selection adjustment circuit, proportionality coefficient selection adjustment circuit, adder I and adder II；Than Output signal S0 and signal S1, signal S0 and signal after handling are compared compared with output signal of the device circuit to instrument amplifier I Input signal of the S1 respectively as proportionality coefficient selection adjustment circuit and biasing selection adjustment circuit；The defeated of circuit is adjusted in biasing selection Input of the output of adjustment circuit as adder I is selected with proportionality coefficient out, the output of adder I is with instrument amplifier II's Export the input as adder II.

Specifically, instrument amplifier I output voltage signal VT, comparator circuit output signal S0 and signal S1, biasing choosing Adjustment circuit output voltage signal VB is selected, proportionality coefficient selects adjustment circuit output voltage signal VK, adder I output voltage letter Number VC, adder II output voltage signal VF, instrument amplifier II output voltage signal VM.Adder II output voltage signal VF It that is to say the output voltage of mV signal measurement temperature compensation means.

Voltage VF and the relational expression of voltage VF are as follows:

VF=VM+VC=VM+VK+VB (2)

In formula (2), VM is mV signal by the amplified voltage of instrument amplifier II, and VK is the ratio-voltage of VM, and VB is Constant voltage.Wherein the selection of VK and VM is determined by temperature selection comparator output S0, S1, the size of the absolute value of VK and VM by Corresponding potentiometer is adjusted.

In this present embodiment, comparator circuit tool is there are two comparing threshold value, wherein first compares threshold value and compare less than second Threshold value；

When the input voltage of comparator circuit compares threshold value less than first, signal S0 and signal S1 are low level simultaneously；

When the input voltage size first of comparator circuit compares threshold value and compares threshold value less than second simultaneously, signal S0 is High level, signal S1 are low level；

When the input voltage of comparator circuit, which is greater than second, compares threshold value, signal S0 and signal S1 are high level simultaneously.

As shown in Fig. 2, comparator circuit includes the first amplifier U1A and the second amplifier U1B, the first amplifier U1A output signal S0, the second amplifier U1B output signal S1；Parallel resistance R1, the first amplifier between the output end and positive input terminal of first amplifier U1A Output end of the positive input of U1A through resistance R2 connection instrument amplifier I, the reverse input end and first of the first amplifier U1A The connection of threshold value comparison voltage end；Parallel resistance R6 between the output end and positive input of second amplifier, the first amplifier U1A is just Output end to input terminal through resistance R5 connection instrument amplifier I, the reverse input end of the second amplifier U1B is compared with second threshold Voltage end connection.

More specifically, the amplification voltage when comparison threshold value of the first amplifier U1A setting is 300 degree of standard K type thermocouple, Amplification voltage when the comparison threshold value of second amplifier U1B setting is 400 degree of standard K type thermocouple.When sodium liquid temperature is lower than 300 degree When, it is less than activation threshold value through the amplified thermocouple amplified signal of instrument amplifier I, two amplifiers equal S0, S1 export as low electricity It is flat；When sodium liquid temperature is between 300-400 degree, S0 output is high level, and S1 output is low level；Sodium liquid temperature is higher than 400 degree When, S0, S1 export as high level.

In this present embodiment, first threshold comparison voltage end includes the resistance R3 and resistance R4 being connected in series, and resistance R3 connects Reference voltage, resistance R4 ground connection, resistance R3 are connect with the connecting pin of resistance R4 with the reverse input end of the first amplifier U1A.Second Threshold value comparison voltage end includes the resistance R7 and resistance R8 being connected in series, and resistance R7 meets reference voltage, resistance R8 ground connection, resistance R7 It is connect with the connecting pin of resistance R8 with the reverse input end of the second amplifier U1B.

As shown in figure 3, instrument amplifier II includes the amplification module I and reference voltage output module of an adjustable gain, one Adjustable voltage input is to reference voltage output module, the reference of the output end connection amplification module I of reference voltage output module End.Instrument amplifier II further includes a filter circuit connecting with the power end of amplification module I.Preferably, filter circuit is low Bandpass filter.

Specifically, the amplification module I of adjustable gain includes accurate low-power consumption instrument amplifier INA118UB, and reference voltage is defeated Module includes an amplifier U2A out, and low-pass filter includes resistance R10, resistance R11, capacitor C4~C6, and one end of resistance R10 connects The negative terminal of mV signal is connect, the other end connects one end of capacitor C4, capacitor C6, and one end of resistance R11 connects the anode of mV signal, separately One end connects one end of the other end of capacitor C6, capacitor C5, and altogether, capacitor C4 is separately connected with capacitor C5 by capacitor C5 and capacitor C4 2 feet and 3 feet of accurate low-power consumption instrument amplifier INA118UB.1 foot and 8 feet of accurate low-power consumption instrument amplifier INA118UB Between connect an adjustable gain resistor, which is connected in series by resistance R9 and potentiometer RA1.

The positive input of amplifier U2A connects adjustable voltage, which is mentioned by constant-current source and a potentiometer RA2 For.Constant-current source is REF200, and 1 foot and 7 feet of constant-current source REF200 is separately connected two fixing ends of potentiometer RA2, potentiometer The positive input of the adjustable end connection amplifier U2A of RA2, the reverse input end of amplifier U2A are connected to accurate low-power consumption instrument and put The low reference pin of big device INA118UB, i.e. 5 feet.6 feet of accurate low-power consumption instrument amplifier INA118UB are as output end, output Voltage signal VM.The 8 foot meridian capacitor C10 of constant-current source REF200 are grounded, while 8 feet connect voltage DVCC；The 1 of constant-current source REF200 The resistance R12 and resistance R13 of series connection in parallel between foot and 7 feet, the common end grounding of resistance R12 and resistance R13, while with 2 feet of REF200 connect, and 2 feet of REF200 meet voltage NVCC.

In this present embodiment, R10, R11, C4~C6 form low-pass filter, R10=R11=10k, C4=C5= 1000Pf, C6=0.047 μ F.

Wherein, differential mode filtering -3DB bandwidth are as follows: BW_DIFF=1/ (2* π * R10 (2*C4+C6))=325Hz；

Common mode filtering -3DB bandwidth are as follows: BW_CM=1/ (2* π * R10*C6)=15.923k Hz.

Voltage VF range is 0-0.6V, and since mV range of signal is contemplated to be 0-20mV, amplification factor is about are as follows: GAIN =0.6/0.02=30

Formula is arranged in the gain of INA118UB are as follows:

GAIN=1+50k/ (R9+RA1)=30, R9=1K, obtains RA1=724 Ω, in view of mV inputs most conference 20 Millivolt fluctuation up and down, it is adjustable that RA1 chooses 1k Ω so that in the constant situation of out-put dynamic range, input mV signal according to bore and Primary transducer difference can change adjustment RA1 and guarantee that dynamic range is constant.

As shown in figure 4, proportionality coefficient selection adjustment circuit includes an a gating module I and amplification module II；The gating mould For block I by signal S0 and signal S1 as input control signal, output end is connected to the controlled end of amplification module II, instrument amplification The input terminal of the output end connection amplification module II of device II；The channel that gating module I is controlled by signal S0 and signal S1, into one Step realizes the adjusting of ratio system selection adjustment circuit output voltage.

Specifically, gating module I be multi-path choice analog switch U3, specially 4052.Control signal S0 and control signal S1 is separately connected 10 feet and 9 feet of multi-path choice analog switch U3.Amplification module II includes amplifier U3A, potentiometer RA4, current potential Device RA5, potentiometer RA3, resistance R14 and resistance R15, resistance R14 and resistance R15 are connected in series and are formed an electrical nodal, should Electrical nodal is connected to the positive input of amplifier U3A, and voltage signal VM is connected to electrical nodal, potentiometer through resistance R14 A fixing end of RA3, RA4, RA5 are connected to electrical nodal through resistance R15, and another fixing end of potentiometer R3A is connected to multichannel 1 foot of analog switch U3 is selected, another fixing end of potentiometer R4A is connected to 5 feet of multi-path choice analog switch U3, potentiometer Another fixing end of R5A is connected to 2 feet of multi-path choice analog switch U3.The controlled end of amplification module II refers to potentiometer RA3~RA5.

In this present embodiment, multi-path choice analog switch U3 is determined in label RK0, RK1, RK2 by control signal S0, S1 As soon as with connecing circuit, the potentiometer where at this moment adjusting corresponding corresponding label, which can make to put U3A, exports relationship proportional to VM Signal VK.

As shown in figure 5, biasing selection adjustment circuit includes a constant-current source and a gating module II；Gating module II is by believing Number S0 and signal S1 is as input control signal, output voltage VB；Control gating module II's by signal S0 and signal S1 Realize the adjusting of biasing selection adjustment circuit output voltage in channel.

Specifically, constant-current source includes chip REF200, and it is a multi-path choice analog switch that gating module II, which is 4052,.

More specifically, constant-current source further includes potentiometer RA6~RA8, and control signal S0 and control signal S1 are separately connected 10 feet and 9 feet of multi-path choice analog switch U4 connect after the fixing end connection of potentiometer RA6~RA8 with 1 foot of REF200 It connects, another fixing end of potentiometer RA6~RA8 is separately connected 12,14,15 feet of multi-path choice analog switch U4, potentiometer RA6 The mobile terminal of~RA8 is separately connected 1,5,2 feet of multi-path choice analog switch U4.Resistance R17 connects to be formed electrically with resistance R18 Node is simultaneously parallel between 1 foot of REF200 and 7 feet, while 13 feet of 7 feet of REF200 and multi-path choice analog switch U4 connect It connects.Electrical nodal is connected to 2 feet of REF200 through capacitor C17, while 2 feet of REF200 connect voltage NVCC, electrical nodal ground connection.

Position multi-path choice analog switch U4 is determined that one in label RB0, RB1, RB2 becomes perseverance by control signal S0, S1 The load of stream source U5, the potentiometer where finely tuning corresponding label at this time can make VB export different voltage values.

In conclusion the output of the present embodiment comparator circuit and corresponding potentiometer relationship are as shown in table 1.

1 comparator of table exports and corresponding potentiometer relationship such as following table

Sodium liquid temperature	VT (thermocouple signal amplification voltage)	S0 output	S1 output	VK adjusts potentiometer	VM adjusts potentiometer
						Less than 300 degree	Less than 0.43V	Low level	Low level	RA1	RA2
300-400 degree	0.43V~0.57V	High level	Low level	RA4	RA7
						Greater than 400 degree	Greater than 0.57V	High level	High level	RA5	RA8

It can show that the mV input of three temperature ranges is as follows with output relation formula:

VF=VM=K1*V_mV+VB1 (3)

VF=VM+K2*VM+VB2 (4)

VF=VM+K3*VM+VB3 (5)

In above formula, formula (3) is voltage and input mV signal of less than the 300 degree outputs of sodium liquid temperature to 4-20mA conversion circuit Relational expression；Formula (4) be sodium liquid temperature between 300-400 degree when output voltage and mV signal relational expression；Formula (5) is sodium liquid The relational expression of output voltage and mV signal when temperature is greater than 400 degree.Table is three linear systems for compensating section respectively by K1, K2, K3 Number is adjusted with RA1, RA4, RA5.

The above-described embodiments merely illustrate the principles and effects of the present invention, and is not intended to limit the present invention.It is any ripe The personage for knowing this technology all without departing from the spirit and scope of the present invention, carries out modifications and changes to above-described embodiment.Cause This, institute is complete without departing from the spirit and technical ideas disclosed in the present invention by those of ordinary skill in the art such as At all equivalent modifications or change, should be covered by the claims of the present invention.