CN201488835U

CN201488835U - Temperature measurer with improved structure

Info

Publication number: CN201488835U
Application number: CN2009201970940U
Authority: CN
Inventors: 李超
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-09-16
Filing date: 2009-09-16
Publication date: 2010-05-26
Anticipated expiration: 2019-09-16

Abstract

The utility model provides a temperature measurer with an improved structure. The temperature measurer with the improved structure comprises a multi-vibrator, a main control module and a display module, wherein the multi-vibrator, the main control module and the display module are connected in turn; an apparatus uses a temperature measuring method similar to R-F inversion frequency; a thermistor is directly connected to a multi-vibrator circuit formed by an RC; and the main control module is used for obtaining an pulse width of high and low levels of an output signal for the multi-vibrator and counting at the same time by using a CPU capturing function thereof. The thermal resistance Rt is in proportion to a difference value between the counted values obtained when the high and low levels are captured. A temperature value can be obtained by looking up a table, and is displayed in the display module.

Description

Improve the thermal detector of structure

Technical field:

The utility model relates to a kind of electronic equipment, especially a kind of thermal detector that improves structure.

Background technology:

Thermal detector is industrial circle a kind of equipment commonly used, traditional thermal detector adopts the method for digital measurement resistance, earlier resistance value is converted to electric signal (as voltage), is converted into digital signal with A/D converter again, so circuit complexity, cost height, maintenance are big.

Summary of the invention:

For overcoming the shortcoming that traditional thermal detector circuit is responsible for, cost is high, maintenance is big, the utility model provides a kind of thermal detector that improves structure.

The utility model comprises multivibrator, main control module, display module, it is characterized in that, multivibrator, main control module, display module connect successively, instrument adopts class R-F inversion frequency to measure method of temperature, directly thermistor is received in the multivibrator circuit that is made of RC, obtain the pulsewidth of multivibrator output signal high-low level and counting simultaneously with the CPU capturing function of main control module, then the difference of the count value of thermistor Rt when catching high-low level is proportional, tabling look-up to get temperature value, displays temperature value in display module.

The beneficial effects of the utility model are, have simplified the circuit complexity of equipment, have reduced the cost of equipment, have higher utility.

Description of drawings:

Fig. 1 is a schematic diagram of the present utility model, and Fig. 2 is the utility model electricity structural drawing.

Embodiment:

As shown in Figure 1, the utility model comprises multivibrator 1, main control module 2, display module 3, multivibrator 1, main control module 2, display module 3 connects successively, adopt class R-F inversion frequency to measure method of temperature, directly thermistor is received in multivibrator 1 circuit that is made of RC, obtain the pulsewidth of multivibrator 1 output signal high-low level and counting simultaneously with the CPU capturing function of main control module 2, then the difference of the count value of thermistor Rt when catching high-low level is proportional, tabling look-up to get temperature value, displays temperature value in display module 3.

As shown in Figure 2, be that core is formed typical multivibrator with the NE555 timer, as in one of timing element place in circuit, NE555 timer output pin connects the P1.2 pin of MSP430 single-chip microcomputer tested thermistor Rt.By measuring principle as can be known, the error main source is R1, R2 precision, the timer of single-chip microcomputer and the precision of capacitor and degree of stability.Select high precision, temperature coefficient precision metallic paper tinsel resistor for use, and the frequency of operation of single-chip microcomputer is enough high, just can obtain temperature measurement accuracy preferably less than 0.3 * 10-6/ ℃ in soil.A fixing clock frequency f and count mode are set for timer A by MSP430 single-chip microcomputer TACTL register, behind the timer A continuous mode count enable, the value of TAR begins the continuous repeat count from O-FFFFH, and it stops till the counting until software control; CMx, CAP, the CCIE position of TACCTL register are set simultaneously, and rising edge and the negative edge of exporting square wave at multivibrator all trigger seizure and interruption.Arrive when each edge like this, enter interruption and catch rising edge and negative edge value constantly, tabling look-up promptly gets temperature value, and corresponding temperature digital amount is passed through display module BTL003 and driven display screen demonstration relevant temperature.

Claims

1. a thermal detector that improves structure comprises multivibrator (1), main control module (2), display module (3), it is characterized in that, multivibrator (1), main control module (2), display module (3) connect successively.