JPS5985106A - Linearizing circuit - Google Patents

Abstract

PURPOSE:To compensate the measuring temperature versus converting voltage characteristic of an input signal by providing a nonlinearity compensating circuit using a Zener diode to an input circuit of an operational amplifier. CONSTITUTION:The measured output of a temperature measuring circuit 1 is amplified at an amplifier circuit 9 and inputted to a linearizing circuit 10. Said linearizing circuit 10 has an operational amplifier 25, a series circuit comprising resistors 28, 29 and a Zener diode 30 is connected to the 1st input and a circuit comprising resistors 26, 27 and a Zener diode 31 connected between a connecting point of the resistors and ground is connected to the 2nd input. An input signal is impressed to a connecting point between the resistors 28 and 26. Thus, the measuring temperature versus converting voltage characteristic of the input signal is compensated and linearized by the circuit comprising the Zener diode and the resistors, and a compensated output is obtained between terminals 23 and 32.

Description

TECHNICAL FIELD The present invention relates to a linearization circuit that compensates for an output signal obtained by a change in resistance value due to temperature, for example, of a resistor so that it changes linearly with respect to temperature change.

Conventional technology Conventionally, as a circuit for converting changes in resistance value due to temperature changes into heavy pressure, a resistance temperature detector is connected to one side of a total resistance bridge, and other elements are adjusted at a certain reference value of the resistance temperature detector to maintain balance. After that, the voltage generated due to the unbalance of the bridge due to the change in the resistance value of the resistance temperature sensor is measured with a meter.
r, a similar circuit was used. In this circuit, the temperature measuring resistance element is generally connected to the main body of the measuring circuit.
1. In this case, the measurement will be inaccurate due to the influence of the lead wire, and even if you use a lead wire with a thicker cross-sectional area to avoid this, the measurement error will still be avoided. There was a problem in that it was not possible to lower the value below a predetermined value.

To solve this problem, two operational amplifier circuits are used, and a temperature measuring resistance element is connected to the feedback resistance of one of the operational amplifier circuits t2, and the other /1437 h'zll~゛1
1ll as a feedback resistor for a single circuit at a reference angle of 18''
11 temperature 4I (all resistors with the resistance value of the resistance element are connected 7,
The inventor invented a circuit for determining the difference between the two width scale circuits.f1. ! -+fj showed lj-ta(ko), 'membrane OK
; see No. 54-102795).

This 11 circuit beggar 1t1? , 6 and the shadow of the lead wire;
However, in commercially available RTDs, there is a non-linear relationship between yilA Jg and its resistance value, and there is a difference of, for example, several Ω-cents at the maximum point. , measurement temperature and 1 conversion voltage! ? , another problem arose in that the linear relationship was foreign to the value and could not be applied to the 1μ case.

Purpose of the invention (/i) In view of the above-mentioned problems, the present invention is based on the concept of providing a circuit network of resistors and Zener diodes in the input circuit of an amplifier circuit to compensate for the nonlinearity of the input signal. , the measured temperature vs. converted voltage characteristic caused by the temperature vs. resistance value characteristic of the resistance thermometer element is compensated for an iIV linear relationship, and is suitable for applications that require a 1M linear measured temperature vs. converted voltage characteristic. The goal is to be able to adapt.

Structure of the Invention According to the present invention, a resistor 2 is connected to the first input circuit of the operational amplifier.
and an in-line circuit of Zener diodes, a resistor connected in series to the second input circuit is provided, another Zener diode is connected between the series connection point of the resistor and the point TLB, and the second input circuit is , product amplification of series circuits connected to one input circuit? 1: Opposite ■ 111 - (Confucian, 1 is thrown into the second input circuit, nλ curve sequence j: ['i, i< of the pile circuit
F< Opposite of operational amplifier (111 and 41, and add a number to input Kai, 1-1 the human power signal supply point and the operational amplifier) Take the output from between the output terminals of 2 An i71' wiring circuit is provided.

Embodiment A demand measuring device using an α-ray converting circuit as an embodiment of the present invention is shown in [1() If route diagram] 12j.This device has a temperature measuring circuit 1. Amplification circuit 9. Includes OR and linearization circuit 10.

Temperature 3 + il 5: j Snow (4) Ichiko about road 1 [yj
do. N rule J performance resistance person 13 is the first performance 10Xl width instrument 1
Connect the lead wire 18 from the inverted input of 1 to -☆1.
1.1) 1, 11 ρ ↓ FC + 11 The other end of the element 13 (Du, one end 1 of the lead wire 6 and 17 is connected. Force 2, the other end of the lead wire 1i-1) Hatakaki 1 performance; ζ1
, J& continued to the output of amplifier 11, JI, demaru・su, 4I,
1 constant 71ij pressure jul change 11C source 6a is second calculation increase 1
ij, vessel 11), evening), each erasure number 'I intensifier's 76, source and [7 used) 9, as well as the neutral point being grounded, cuff, box 4
Divide the pressure into the first operational amplifier circuit 7
Supply to 0. A resistor 12 having an appropriate resistance is inserted between the input terminal 40 and the inverting input of the first operational amplifier 11. The non-inverting input of the first operational amplifier 11 is grounded. The output terminal of the first operational amplifier 11 and the output terminal of the second preamplifier 19 are connected to each other. Second part for canceling the influence]: Feedback resistor 1 of amplifier circuit 8
A constant voltage current power source 6b connected to one end of the second operational amplifier 11 and 92 supplies a power source for the second operational amplifier 9.
Voltage Zenrō′,! ; U is applied to the input terminal 41 which leads to the inverting input of the second operational amplifier 19 through a suitable resistor 2:÷14; The inverting input U niobium oxide 1 (connected to the other end of the resistor 15) is connected to the input. The neutral point of the second constant voltage DC power source 6b is fixed at the first position and is connected to the non-inverting input terminal of the second performance amplifier j9, and the neutral point and the ground point are connected to the non-inverting input terminal of the second performance amplifier j9. The voltage between the first lead amplifier circuit 7 and the base if Q' is the lead pressure setting lead! This is the output of the system L·(: of the second operational amplifier circuit 8 for canceling the influence.

Next, I will explain Tsukuda's first work. ;lj ] rt'j, the amplification of the arithmetic amplifier circuit 7, 4G .Therefore, input 9″11.
1 child 40 always has a constant 1f1 style't! Pressure applied]1
．． Tefu・Reha 1st performance 1*i+iQ l illuminator 11 output 1
171. Proportional to G, that is, 1N12 is constant. iJ R, 3 to 1...1] output! I can.

Second. Reconnaissance increase 'M device 19 (Similarly for C, resistor 1
Proportional to 5, 7p and increase liv, '1 degree is given, ft is applied to input terminal 11, input terminal 1''4 () and turn 'toshi, 11, resistor x: 112 and ] 4 resistance (target II
+1- and measurement? 1. ＋'+ 'J': Anti-Song 2 ■' Please note the resistance value at a certain standard temperature (for example, 0℃ and 5 J:lS'G is good). If specified, then), l-j'lfi 1・嘉；仄VC
The output of Qri (d: ji1 level) is 1 level.If the output circuits are connected in series, the output is 1. , when the quasi-temperature fg- is reached, the output is turned off and becomes 0, and the resistance value of the temperature resistance element changes 1171 times, with 7 quality changes from the basic 1. (Difference W, force) -k X (Rt Rr) --
-(2), and the desired relationship is obtained. Here, k is a constant of proportionality, and Rt is t°C. The resistance value of the resistance temperature measuring element, R
r is the resistance value of the 611J temperature resistance element at the reference point Vc.

Generally, the resistance temperature detector is often installed at a location far away from the main body of the temperature measurement circuit, and the resistance value of the IJ -1' wire is not added to the resistance value of the resistance temperature detector, resulting in an error. In this circuit, the force of the wires 17 and 18 is added to the temperature measuring resistance element which is the resistance for the feedback circuit of the first operational amplifier 11, and the feedback circuit of the second operational amplifier 11 is Since the lead wires 16 and 17 are added to the resistor 15 for the purpose, the effect is the same if the lead wires 16, 17, and 18 are the same and have the same value. By taking the difference in the outputs of the operational amplifiers, it is possible to eliminate errors that occur in the voltage due to the resistance values of the lead wires.

Explanation of the amplifier circuit 9-(1jjl) The output of the temperature measuring circuit 1 described above is placed above 'r10 between the support 4:3 and the ground point.

The output of the terminal 43 is supplied to the input terminal of the amplifier circuit 9. The input terminal is connected to the inverting input of the operational amplifier 200 through a suitable resistor 21, and the feedback resistor 22 is inserted between the inverting input and the output of the amplifier 2o. i;-, J:bi22ke1lIij
', the desired amplification degree, which will be described later, in the 1-width circuit 9 is determined to be 1 degree.

Linearizing circuit 1 (1(tC), then 6 and 7. The output of the amplifier circuit 9 is connected to the W-line converting circuit network 11'1 line converting circuit 1 (). Input terminal resistance redundancy 1: 28, Zener diode: 30% U
'-i>j-, k amplification through 29? ×25
Connect to the inverting input of the zener diode.
1 K, Yang (returning to Tsumugi-sa). The remainder of the network is connected from the input end to the non-inverting input of the amplification circuit 25 through resistors 26:1L- and 27,
(1
or inserted. Zener diode, ']1 direction (7
J, the positive A version is connected to the pond: 1) 7. Ru. A feedback resistor' (3) is connected between the inverting input and the output of the operational amplifier 25.
is connected h'.

The operation of the above-mentioned circuit will be explained with reference to the complete characteristic diagrams shown in FIGS. 2 to 5. The 11w3 circuit 9 appropriately amplifies the output of the difference between the 116th operational amplifier circuit 7 and the 2nd operational amplifier circuit 7, %I, pressure setting, and Vf'X' for canceling the influence of the 16th line. 6()] The transformation Δノ″l-dil′ corresponding to the crystallinity range ('ro-T,) defined
, the output value ij, ij, and the range (Vo to V11) are if,
For the input of the linearization network, it is required that the voltage be approximately twice the voltage of the Zener diodes 30 and 31 used in the linearization network, so the resistor must be set to meet that condition. The output terminal 23 has a total of 43 outputs, and the output terminal 23 has a perfectly directly proportional if,'+tlQ!?1'1 <Slightly upwardly convex temperature (r)? Pressure force M75B4! r) IL le (2nd L"',: Break Md). The absolute value differs between the mochi ring and the circuit of the operational amplifier 20 by one degree and one degree.

The reason why the l1ft line in this graph is not the 1h line is 1' of the resistance temperature measurement table! 'X, IL' depends on the same characteristics of the resistance class. Night fl'): I conversion 1!': II',
X41 pcs. 2 Zener diodes 3 (1
, :l ] at the input of the network.
3. -i'11.7.1 Tax sub-determination iQ) 1jjl
('I' o ~ E' I ) Vl corresponding voltage 'j
'i>t! tl (vo-Vll) is required to be half.1.For the first branch, if the input mark Jlil frost, the pressure V, is less than or equal to v, 72, then the guide i
76, Tin vl, /2L-J, above is the voltage I of (applied voltage -v,, /2)] for! Related (4th [n1)
44) It is applied to the inversion input of the i-calculation J stomach 11 prefecture device 250. In the second branch, the input [)” weight is used as vi
In the case of +/'21 counter-t, conduction to that extent is "1+/2
The total exceeds 1 and takes a constant value of 11/2 (Ff>
4 I45). The output of the first branch (with different loss characteristics,
11' of the second branch) J - Then fold (Ydi!-shaped output 'Ichikawa is 11 children)') - (go f'!, 51
Shisho 16). The return of the Enkin Amplification Domain 25 jJ (anti-33m1 illness ni soul bu C and the broken line can be converted (
2→C5 Figures 46-47) Eventually, the arc-shaped 'l(j, lf
It is possible to change f- to 41 (31st n]). Here, the gland changes into an arc f (-J'! c; More Konoesu Gonoi τ-1
゛den, +F:, goo blindness i1. I' / 114 Song Gentleman is a handy literary writer 'I' ¥ 4;-C is not shown-Matame. By subtracting this arc-shaped output power Ichikawa (Figure 3) from the output f8', I (plane 72) from the dashed line, that is, Example (1st 1) C'
By drawing out the output from between terminals 23 and 32, a conversion characteristic corresponding to a directly proportional straight line can be obtained (2J' solid line in Figure 2).

Effects of the Invention According to the present invention, it is possible to compensate for the constant temperature vs. converted voltage characteristics caused by the temperature vs. resistance characteristics of the temperature resistance. Temperature versus conversion voltage 1.1 is required. It can be adapted to various applications.

4 A simple explanation of the drawings, 1 in Figure 1, 1 in -pyIi + i example of the invention and 11 in 12
Circuit diagrams of the one-wire circuit, Figures 2 and 3.

Figures 4 and 51 are characteristic diagrams illustrating the operation of the device shown in Figure 1.

DESCRIPTION OF SYMBOLS 1...Temperature measurement circuit, 6a-1st constant voltage part m1 power supply, 6b...2nd constant voltage 1α flow source, 7...1st operational amplifier circuit, 8...Base 1. t E[Setting button and second operational amplifier circuit for canceling read net effect, 9...Additional 1[
・Hata circuit, 1()... linearization circuit, 11・aP, ]
Operational amplifier, 12...Resistor, ]3...1ill temperature resistance element, 14.15...Resistor 2(), 16, 17.1
8... Lead wire, 19... Second operational amplifier, 20...
...Operation amplifier, 21.22.Resistor, 23..Amplification circuit output terminal, 24..Ground terminal, 25..Operation amplifier, 2F+, 27.28.29..Resistor, 30.
31... Zener diode, 32... Linearization circuit H1 power)'/! 1.1 child, 33...resistor 1.4 (
1, 41...Input terminal, 42...Second constant ■, neutral point of direct current power supply, 43...Output terminal JIA terminal.

patent applicant Nippon Lanco Co., Ltd. Cattle FlF application fee, 1 ri person ``Patent Attorney'' - Akira Yoiki Patent attorney Kazuyuki Nishi Patent attorney Yama [1 Akira] 2nd V ゝ′1 Figure 3 ■ Figure 4 ^1Vλ 50th

Claims (1)

[Claims] A series circuit of a resistor and a Zener diode is connected to the first input circuit of the operational amplifier, a resistor connected in series is provided to the second input circuit, and another Zener diode is connected between the series connection point of the resistor and the ground point. and one 1d4 on the opposite side of the operational amplifier of the series circuit connected to the first input circuit;
The series resistance circuit provided in the second input circuit is fully connected to one end on the opposite side from the operational amplifier, and an input signal is applied. A linearization circuit that extracts output from between.