CN2101860U - Complex type temp. testing resistance box with half temp. scale - Google Patents

Abstract

The utility model relates to a complex type temp, testing resistance box with half temp, scale which is a special purpose resistance box which comprises a temperature division circle and a resistance graduation deviation circle. When the indicated value of the temperature division circle is t, the poled resistance value of the temperature division circle is the resistance value of thermal resistance at t degree. The simulation of various resistance values of thermal resistances can through the switching of the graduation select switch of the resistance box. The resistance graduation of the deviation circle has both positive and negative value negative values, which can directly add and reduce the total resistance of the resistance box. The instrumentation can be used as a standard; at the time of the calibration of a temperature measurement secondary instrument which is used with the thermal resistance, the utility model does no need to go through a temperature / resistance comparison table and can directly read the resistance error value of the tested instrument through the deviation circle. The utility model can simplify the operation performance and reduce the times of operation and human errors. The highest instrument accuracy can reach 0.02 grade.

Description

Complex type temp. testing resistance box with half temp. scale

The utility model is a kind of as standard, the special resistors case of the thermometric secondary instrument of calibration adapted thermal resistance.

The thermometric secondary instrument indicating value of adapted thermal resistance is a temperature value, if use the conventional, electric-resistance case when it is calibrated, indicating value is a resistance value, so must pass through the comparison that " temperature/resistance table of comparisons " could realize " standard " and " tested ".The inventor has obtained power " Resistance box for measuring temp. " patent (application number 85100333.8) a kind of non-linear resistance case with temperature scale is provided, its rotating disk is a temperature scale, the resistance value of its access is the resistance indicating value of thermal resistance correspondence under this temperature, realized " standard " direct contrast, but the design concept that this patent provides still there is following deficiency with " tested ":

1. the structure more complicated must be used two coaxial resistance boxes of coordination rotating disk brush;

2. numerous design concept with the type instrument that can adapt to multiple thermal resistance is not provided;

3. the design concept in subzero temperature district is not provided;

4. the design concept that can provide " tested " meter resistance error amount is not provided, provides temperature error values and do not meet existing temperature instrumentation vertification regulation.

The utility model is can adapt to the Resistance box for measuring temp. that multiple Re Dian Zu And has the subzero temperature district through what improvement provided on 85100333.8 patent of invention bases, this resistance box is made up of temperature dish (dish more than 10 ℃) and deviation dish, and deviation dish zero-bit has positive negative resistance scale in the centre.Utilize the temperature dish to select measurement point during use, utilize the deviation dish to increase then or reduce resistance to make " tested " and " standard " synchronous, just can directly read the resistance error value of tested instrument like this by the deviation dish.This numerous principle and method for designing with type half temperature scale Resistance box for measuring temp. is as follows:

The thermoelectric equation of the positive warm area of platinum resistance thermometer sensor, is:

Rt＝R ₀（1＋At＋Bt ²）……………………①

In the formula:

The resistance value of Rt-thermal resistance in the time of t ℃.

R ₀The resistance value of-thermal resistance in the time of 0 ℃.

A, B-constant.

Platinum resistance subzero temperature district and positive warm area are not continuous function (the subzero temperature district are equations of higher degree), but we distinguish section with subzero temperature and 1. represent with formula, still can obtain gratifying degree of accuracy.Different like this platinum resistance, different warm areas, 1. we will represent with formula, just their Ro, A, B value are different, and the variation of these 3 parameters only need change 3 monodrome resistors of resistance box and the stepping resistance value that its adaptation And need not change the temperature dish, has so just realized a tractor serves several purposes.

The schematic circuit of this resistance box such as Fig. 1.R among the figure _P1, R _P2Be two the stepping resistors (temperature dish) with temperature scale, for example R _P1Be * 50 ℃ of dishes, R _P2Be * 10 ℃ of dishes, R _T0, R _P0, R _nBe the monodrome resistor.The circuit set of data is calculated as follows:

If the Resistance box for measuring temp. operation interval is t ₁～t ₂(t ₂＞t ₁)

1. temperature dish R _p(R _P1, R _P2) calculating of step value:

The stepping resistance value R of unit's of obtaining (1 ℃ of temperature) earlier _p', can obtain R _P1, R _P2Step value.

$({2B}_{\mathrm{tl}}+A)R_0\≤{R_D}^{\′}\≤\sqrt{A^2-4B}{R}_0$

2. imaginary lower limit t ₀Calculating;

$t_0=\frac{\frac{{R_P}^{\′}}{R_0}-A}{2B}$

3. top resistance R _P0Calculating;

R _p0＝（t ₁－t ₀）R _p′

4. And joins resistance R _nCalculating;

R _n＝ (RP′)/(-B) 〔 (RP′)/(R0) ＋B（t ₂－t ₀）〕

5. imaginary lower limit resistance R _T0Calculating;

R _t0＝R ₀（1＋At ₀＋Bt ² ₀）

Consider the error of manufacturing of each resistor, this resistance box complete machine precision can reach 0.02 grade

Calculating exemplifies 1: the circuit that calculates 0～600 ℃ of pt100 platinum resistance thermometer sensor.

Known: R ₀=100, A=3.90802 * 10 ^-3, B=-0.580195 * 10 ^-6, t ₁=0, t ₂=600

1, asks Rp '

$\sqrt{A^2-4B}{R}_0=0.41944487$

（2B _t1＋A）R ₀＝0.390802

0.390802≤Rp′≤0.41944487

Get Rp '=0.41

R then _P1=500Rp '=205

R _p2＝100Rp′＝41

2, ask t ₀

$t_0=\frac{\frac{{R_P}^{\′}}{R_0}-A}{2B}=-165.44437$

3, ask R _P0

R _p0＝－t ₀Rp′＝67.832191

4, ask Rn

R _n＝ (RP′)/(-B) 〔 (RP′)/(R0) ＋B（t ₂－t ₀）〕=2583.4695

5, ask R _T0

R _t0＝R ₀（1＋A _t0＋Bt ² ₀）＝33.75591

Mapping, (as Fig. 2, resistance value is got 5 figure places.）

In order to make R _P2In shared its scale value of positive and negative warm area, among the figure with R _pAnd R _nTransposition.

Checking computations:

1、0℃

Rt＝ (67.832（205＋2583.5＋41）)/(67.832＋205＋2583.5＋41) ＋33.756＝99.999923

2,100 ℃ (standard value is 100.00)

Rt＝ (（205＋2583.5）（41＋67.832）)/2897.332 ＋33.756＝138.49995

(standard value is 138.50)

3、500℃

Rt＝ (（205＋67.832）（2583.5＋41）)/2897.332 ＋33.756＝280.89631

(500 ℃ of standard values are 280.90, and by formula 1. this point value is 280,89613, and standard value has only been got 2 significant digits, so this difference is arranged).

Calculating exemplifies 2: calculate; P _T100The circuit of thermal resistance-100～0 ℃

Known (tabling look-up).R（0℃）＝100、R（－50℃）＝80.31、R（－100℃）＝60.25

1. above-mentioned 3 substitution formula are solved:

R ₀＝100 A＝3.901×10 ^－3B＝－0.74×10 ^－6

（t ₁＝－100 t ₂＝0）

1, still gets R _p'=0.41

2, ask t ₀

$t_0=\frac{\frac{{R_P}^{\′}}{R_0}-A}{2B}=-134.45945$

(annotate: must t ₀≤ t ₁Otherwise choose R again _p')

3, ask R _P0

R _p0＝（t ₁－t ₀）R _p′＝14.128374

4, ask Rn

R _n＝ (R _P′)/(-B) 〔 (R _P′)/(R ₀) ＋B（t ₂－t ₀）〕=2216.4932

5, ask R _T0

R _t0＝R ₀（1＋At ₀＋Bt ² ₀）＝46.20951

Mapping, (as Fig. 3, resistance value is got 5 figure places.）

In order to make R _P2In shared its scale value of positive and negative warm area, Rp and Rn are replaced among the figure.

Checking computations:

1、0℃

Rt＝ (2216.5（41＋14.128）)/(2216.5＋41＋14.128) ＋46.21＝100.00014

2、50℃

Rt＝ (（2216.5＋41／2）（41／2＋14.128）)/2271.628 ＋46.21＝80.310141

3、－100℃

Rt＝ (（2216.5＋41）14.128)/2271.628 ＋46.21＝60.250132

To go up two figure merging and promptly obtain P _T100-100～600 ℃ schematic circuit (as Fig. 4).K among the figure ₁And K ₂Coaxial, when pointing to "+", be 0～600 ℃ of positive warm area, when pointing to "-" subzero temperature district-100～0 ℃.At R _P2After be connected in series a stepping resistor (deviation dish) Δ R, Δ R generally forms (as Fig. 5) by the resistor of three 20 steppings, and step value is: * 1 Ω, * 0.1 Ω and * 0.01 Ω, they all are 0 positive and negative ten steppings in the centre, each dish refers to that total resistance in 0 o'clock is 11.1 Ω, so at two R _T0In all deducted 11.1 Ω.Like this deviation dish have ± 11.1 Ω are in order to indicate the error of tested instrument.

Fig. 6 is BA ₁, BA ₂, the numerous schematic circuit of G with type Resistance box for measuring temp. positive warm area.(do not add the deviation dish in order to simplify.) be G type circuit between AB among the figure, between BC BA ₁Circuit is BA between AC ₂Circuit.

Wherein:

G type copper thermistor is applicable to that also formula is 1. only because of B=0 wherein so be written as:

Rt＝ro（1＋at）

In the formula: r ₀=53 Ω a=4.25 * 10 ^-3Ar ₀=2.2525 * 10 ^-1

BA ₁The circuit set of data is calculated same P _T100, wherein:

Ro＝46Ω、A＝3.96847×10 ^－3、B＝－0.5847×10 ^－6

Get R _p=0.19

BA ₂The circuit set of data is calculated like this: (BA ₂A, the same BA of B value ₁, Ro=100)

Because BA ₂Circuit has been used the stepping resistor of G type circuit, so 1. the formula of this moment should be write as:

Rt＝R ₀（1＋At＋Bt ²）－roat

Rt＝R ₀〔1＋（A－ (r0)/(R0) a）t＋Bt ²〕

That is: R _t=R ₀(1+A ' t+Bt ²) ... 1. '

In the formula:

A '=A-(r ₀)/(R ₀) a=(3.96847-2.2525) * 10 ^-3=1.71597 * 10 ^-3Again because BA ₂Circuit has been used BA ₁The stepping resistor of type circuit, then: Rp '=0.19 utilizes formula 1. to exemplify the BA that 1 method is calculated by calculating ₂Circuit is promptly as accompanying drawing 6.

The utility model has solved the deficiency of 85100333.8 patents in theory with in the practice, provide and adapted to multiple Re Dian Zu And and have the Resistance box for measuring temp. that subzero temperature Qu And can directly provide tested meter resistance error amount, simultaneously simplify circuit relatively, reduced use resistive element quantity.

This Figure of description catalogue is as follows:

Accompanying drawing 1: numerous with type half temperature scale Resistance box for measuring temp. schematic diagram.

0～600 ℃ of Resistance box for measuring temp. basic circuit diagram of accompanying drawing 2:pt100.

Accompanying drawing 3:Pt100-100～0 ℃ of Resistance box for measuring temp. basic circuit diagram.

Accompanying drawing 4:Pt100-100～600 ℃ of Resistance box for measuring temp. basic circuit diagram.

Accompanying drawing 5: Δ R resistance deviation dish circuit diagram.

Accompanying drawing 6:BA ₁, BA ₂, G is numerous with type Resistance box for measuring temp. basic circuit diagram.

Claims (6)

1, a kind of as standard, the special resistors case of the thermometric secondary instrument of calibration adapted thermal resistance, this resistance box are one and satisfy the thermoelectric equation of thermal resistance:

R _t=R ₀(1+At+Bt ²)…………①

In the formula: R ₀A, B are the non-linear resistance case of constant, and the resistance value of its access is Rt when its rotating disk is t, and feature of the present utility model is: it is stepping resistor (temperature dish) R that indicates temperature scale by two _P1, R _P2With two monodrome resistor R _P0, R _nRespectively be the quadrilateral closed-loop path formed on one side (R wherein _P1R _P2Opposite side), pass through R _P1, R _P2The stepping brush make the closed-loop path become Gai And connection branch roads of two variable branch road Hu Xiang And connection ， again with resistor R _ToThe formation that is in series circuitry, the all-in resistance of this circuit is Rt when two temperatures dish indicating value is t, when 1. the thermoelectricity of different thermal resistances or a kind of different warm areas of thermal resistance relation can be represented with formula, the R of formula in 1. ₀, A, B or difference is arranged, resistance box is by switching different R _To, R _Po, R _nWith its adaptation, just can insert corresponding R _tValue.

2, according to claim 1, this resistance box has two stepping resistor R _P1And R _P2, it is characterized in that: their step value is respectively the stepping resistance value R of unit (1 ℃ of temperature) _p' integral multiple, when the Resistance box for measuring temp. operation interval is t ₁～t ₂(t ₂＞t ₁) time R _p' choose and should satisfy:

（2B _t1＋A）R ₀≤R _p′≤

R ₀

3, according to claim 1, this resistance box has the certain value resistor R _P0, it is characterized in that: when the Resistance box for measuring temp. operation interval is t ₁～t ₂(t ₂＞t ₁) time:

4, according to claim 1, this resistance box has the certain value resistor R _n, it is characterized in that: when the Resistance box for measuring temp. operation interval is t ₁～t ₂(t ₂＞t ₁) time:

R _n＝ (R _P′)/-3 〔 (R _P′)/(R ₀) ＋B（t ₂－t ₀）〕

5, according to claim 1, this resistance box has the certain value resistor R _T0It is characterized in that:

R _t0＝R ₀（1＋At ₀＋Bt ² ₀）

6, according to claim 5, resistance box has a resistor R _T0, it is characterized in that: if with R _T0Resistance value reduces by 1/2 Δ R, and be connected in series the resistor (deviation dish) that a last resistance value equals Δ R to it, this resistor zero-bit is in the centre, scale is ± 1/2 Δ R, adjust the all-in resistance of Δ R changeable resistance box, in order to the error of direct indication thermometric secondary instrument, Δ R also can be made up of the different multidigit stepping resistor in series of the identical only step value of form, so that the multidigit numerical value of reading error.