CN2365677Y

CN2365677Y - Apparatus for measuring resistance quantity with one chip machine

Info

Publication number: CN2365677Y
Application number: CN 99227504
Authority: CN
Inventors: 谈金华; 马仁源
Original assignee: JANGSU SHINCO ELECTRONIC GROUP AIR CONDITIONER MANUFACTURING Co Ltd
Current assignee: JANGSU SHINCO ELECTRONIC GROUP AIR CONDITIONER MANUFACTURING Co Ltd
Priority date: 1999-03-15
Filing date: 1999-03-15
Publication date: 2000-02-23
Anticipated expiration: 2009-03-15

Abstract

The utility model relates to an apparatus for measuring resistance value, provided with a single-chip computer and a charge and discharge path. The single-chip computer comprises a CPU, a memory, a timer, and an input and output port. The charge and discharge path is composed of a resistor R and a capacitor C. The other end of the resistor R is connected with one port of the input and output port. A public connecting point of the resistor R and the capacitor C is connected with the other port of the input and output port of the single-chip computer; the other end of the capacitance C is connected with the ground. The utility model has simple structure; an analog to digital converter is not arranged in the single-chip computer, and the single-chip computer is not externally connected with a voltage comparator; thus, the cost is low.

Description

The device that utilizes single-chip microcomputer that resistance value is measured

The utility model relates to a kind of device that resistance value is measured.

The existing device that utilizes single-chip microcomputer that resistance value is measured mainly contains two kinds of forms.A kind of is to comprise A/D converter in single-chip microcomputer, directly the resistance of resistance is measured; Another kind is do not have A/D converter in the single-chip microcomputer, but the external voltage comparer to be measured to the resistance of resistance by voltage comparator by single-chip microcomputer; The cost of these two kinds of measurement mechanisms is all higher, structure is also comparatively complicated.

The purpose of this utility model is to provide a kind of structure simpler, the lower-cost device that utilizes single-chip microcomputer that resistance value is measured.

The technical scheme that realizes the utility model purpose is that this device has single-chip microcomputer, comprises central processing unit, memory, timer and input/output port in the single-chip microcomputer; Its design feature is also to have the circuit of charging and discharging; Discharging and recharging the series connection of routing resistance R and capacitor C constitutes; The other end of resistance R links to each other with a port of single-chip microcomputer input/output port; The common junction of resistance R and capacitor C links to each other with another port of single-chip microcomputer input/output port; The other end ground connection of capacitor C.

Above-mentioned resistance R is for converting physical quantity to the sensor of resistance value.And the sensor R that physical quantity can be converted to resistance value is the pressure transducer that thermistor, hygristor maybe can be converted to force value resistance value.

The utlity model has positive effect: after in the single-chip microcomputer of this device, relevant procedures being set, promptly can be used for measurement to temperature.During use, the time that reaches predetermined high level numerical value according to the voltage that charges and discharge the electric capacity in the circuit obtains corresponding resistance value.The circuit structure of this device is simple, reliable operation when using, because of do not have in the single-chip microcomputer A/D converter and single-chip microcomputer again the external voltage comparer so cost is not lower.

Drawing of the present utility model is described as follows:

A kind of electrical schematic diagram when Fig. 1 uses for the utility model.

The block diagram that is used for the program of measured resistance value in Fig. 2 the utility model single-chip microcomputer.

The utility model will be further described below in conjunction with drawings and Examples.

Embodiment 1,

See Fig. 1, single-chip microcomputer 1 is produced by Taiwan winbond electronics company limited, and its model is W741C260, comprises central processing unit, memory, timer and input/output port during single-chip microcomputer 1 is established.Resistance R is a thermistor, is produced by MIT, and its model is PART NO 150-103-83015; The resistance of this thermistor and the corresponding relation of temperature are provided by table 1, and the high more then resistance value of temperature is low more as shown in Table 1.Capacitor C is an electrochemical capacitor, can be common electric capacity also, and its resistance is 1 μ f (in theory value) within the specific limits in the present embodiment.

Resistance R and capacitor C series connection formation charge and discharge circuit 2; The other end of resistance R links to each other with a port I/O1 of single-chip microcomputer 1 input/output port; The common junction of resistance R and capacitor C links to each other with another port I/O2 of single-chip microcomputer 1 input/output port; The other end ground connection of capacitor C.The exportable temperature value of single-chip microcomputer 1 input/output port to a plurality of ports of display are formed the I/O3 port.

See Fig. 2, in the single-chip microcomputer 1 in said apparatus relevant procedures are set after, promptly can be used for measurement to temperature.Can set by 3 pairs of mensuration cycles of keyboard, for example, can be set at 3 seconds, promptly carry out a temperature survey under the timing of the timer (can be described as first timer) in single-chip microcomputer 1 in per 3 seconds.When beginning to measure, at high level that is about 5V of I/O1 port output, another timer (can be described as second timer) of opening then in the single-chip microcomputer 1 carries out timing, the voltage value that the programmed control central processing unit is constantly measured the I/O2 port whether reach the I/O2 port intrinsic threshold voltage (for example 3.5V).Because the 5V high level by the output of I/O1 port constantly charges to capacitor C by resistance R, increase along with the time, the voltage of I/O2 port progressively improves, when meeting or exceeding the threshold voltage of I/O2 port, the programmed control central processing unit is read the numerical value of second timer, (wherein: R is a resistance value to formula by R=τ/kC then, τ is the time numerical value that second timer is read, C is a capacitance, and k is constant, obtains by inserting test after the measuring resistance in circuit), obtain the value of the resistance R of correspondence by central processing unit according to the difference of time τ; Single-chip microcomputer tables look-up 1 to the gained resistance value of gained by look-up method, thereby obtains Temperature numerical, then by the I/O3 port of single-chip microcomputer 1 at display 4 displays temperature numerical value.The signal of gained resistance value also can be transported to other controller and control, and also can be directly used in relevant control operation according to other program that is provided with in the single-chip microcomputer.

Embodiment 2,

Referring to Fig. 1 and Fig. 2, all the other are identical with embodiment, and difference is that resistance R is a hygristor,

Embodiment 3,

Referring to Fig. 1 and Fig. 2, all the other are identical with embodiment, and difference is that resistance R is for being converted to force value the pressure transducer of resistance value.

1℃ KΩ ℃ KΩ ℃ KΩ 0 32.8352 20 12.5030 40 5.3140 1 31.1950 21 11.9503 41 5.1044 2 29.6465 22 11.4251 42 4.9041 3 28.1843 23 10.9259 43 4.7127 4 26.8020 24 10.4513 44 4.5297 5 25.4973 25 10.0000 45 4.3549 6 24.2631 26 9.5706 46 4.1877 7 23.0959 27 9.1621 47 4.0277 8 21.9916 28 8.7732 48 3.8747 9 20.9467 29 8.4030 49 3.7283 10 19.9575 30 8.0504 50 3.5882 11 19.0207 31 7.7145 51 3.4536 12 18.1333 32 7.3945 52 3.3248 13 17.2925 33 7.0894 53 3.2015 14 16.4955 34 6.7986 54 3.0834 15 15.7398 35 6.5213 55 2.9704 16 15.0230 36 6.2568 56 2.8620 17 14.3429 37 6.0044 57 2.7583 18 13.6975 38 5.7636 58 2.6588 19 12.0848 39 5.5336 59 2.5634

Claims

1, a kind of device that utilizes single-chip microcomputer that resistance value is measured has single-chip microcomputer (1), and single-chip microcomputer comprises central processing unit, memory, timer and input/output port in (1); It is characterized in that also having the circuit of charging and discharging (2); Charging and discharging circuit (2) is made of resistance R and capacitor C series connection; The other end of resistance R links to each other with a port of single-chip microcomputer (1) input/output port; The common junction of resistance R and capacitor C links to each other with another port of single-chip microcomputer (1) input/output port; The other end ground connection of capacitor C.

2, the device that utilizes single-chip microcomputer that resistance value is measured according to claim 1 is characterized in that, resistance R is for converting physical quantity to the sensor of resistance value.

3, the device that utilizes single-chip microcomputer that resistance value is measured according to claim 2 is characterized in that, the sensor R that physical quantity can be converted to resistance value is the pressure transducer that thermistor, hygristor maybe can be converted to force value resistance value.