CN104101440B - A kind of Portable low-temp thermometer - Google Patents
A kind of Portable low-temp thermometer Download PDFInfo
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- CN104101440B CN104101440B CN201310118972.6A CN201310118972A CN104101440B CN 104101440 B CN104101440 B CN 104101440B CN 201310118972 A CN201310118972 A CN 201310118972A CN 104101440 B CN104101440 B CN 104101440B
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- current source
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Abstract
A kind of Portable low-temp temperature measuring equipment, comprising: cryogenic temperature sensor, A/D converter, constant-current source, reference resistance, single-chip microcomputer, LCDs, communication serial ports device, switch, power regulator and internal battery；Internal battery is respectively single-chip microcomputer and constant current source power supply after power regulator voltage stabilizing；Constant-current source provides a stabling current for cryogenic temperature sensor；The voltage signal of cryogenic temperature sensor output is read by single-chip microcomputer after A/D converter is converted into data signal, inquires about built-in phasing meter through single-chip microcomputer and is converted to temperature value, showing afterwards on liquid crystal display；In remaining part is placed in a casing in addition to temperature sensor, save space；Machine volume is little, it is simple to carries with and carries out rapidly measurement work；Its certainty of measurement is only determined by reference resistance precision and A/D converter part precision；Be suitable to low temperature environment use.
Description
Technical field
The invention belongs to test the thermometer in measuring instruments field, particularly to one be used for measuring low temperature (about 4K～
300K, or-269 DEG C to room temperature/27 DEG C) Portable low-temp thermometer.
Background technology
Existing low-reading thermometer is many to be made up of, by perseverance cryogenic temperature sensor, constant-current source, accurate voltage table and computer
Stream source provides operating current for sensor, measures the magnitude of voltage of sensor output with voltmeter, senses further according to this
The voltage-temperature phasing meter that device is calculated in advance, is tabled look-up by computer program, converts, obtain dut temperature.A whole set of dress
Put volume relatively big, need Alternating Current Power Supply, it is difficult to realizing miniaturization, on-the-spot application is more inconvenient.
Summary of the invention
It is an object of the invention to provide a kind of Portable low-temp thermometer that can be used in low temperature measurement, measure model
Enclose up to 4K～300K (-269 DEG C～27 DEG C).
For achieving the above object, technical scheme is as follows:
The Portable low-temp thermometer that the present invention provides, comprising: cryogenic temperature sensor, A/D converter, constant current
Source, reference resistance, single-chip microcomputer, LCDs, communication serial ports device, switch, power regulator and in-built electrical
Pond；It is characterized in that: described A/D converter part, constant-current source, reference resistance, single-chip microcomputer, communication serial ports device,
Power regulator and internal battery are placed in a casing；Described LCDs is placed in the fluting of casing, described switch
Draw the perforate of casing；Described cryogenic temperature sensor is placed in outside casing；
Described internal battery is respectively single-chip microcomputer and constant current source power supply after power regulator voltage stabilizing；Constant-current source is low temperature
Temperature sensor provides a stabling current；The voltage signal of cryogenic temperature sensor output is changed through A/D converter
Read by single-chip microcomputer after becoming data signal, inquire about built-in phasing meter through single-chip microcomputer and be converted to temperature value, showing afterwards
Show on liquid crystal display；Or the temperature value drawn is sent to computer through communication serial ports device by single-chip microcomputer, by calculating
Machine embedded software realizes the record of temperature value.
In technique scheme, according to thermometric occasion and the difference of temperature range, described cryogenic temperature sensor can
For platinum resistance temperature sensor, carbon resistance temperature sensor, rhodium-iron resistance thermometer, temperature sensor, electric thermo-couple temperature sensing
The various types of sensor such as device or diode temperature sensor；If it is required, cryogenic temperature sensor is permissible
Pull down replacing.
In technique scheme, A/D converter part is to have the A/D converter ic no less than 10 precision,
The ADS1247 etc. of AD7705, AD7793 or TI company of such as ADI company；When required precision is the highest, also
The internal A/D change-over circuit provided of single-chip microcomputer can be provided；A/D converter part is poor with precision in both reference resistances
Person determines the measuring accuracy of whole Portable low-temp thermometer.
In technique scheme, the described connected mode between constant-current source, cryogenic temperature sensor and reference resistance
There is a two ways: the first is that constant-current source, cryogenic temperature sensor are connected by low temperature constant current source power supply with reference resistance；
The second is to use two on all four first constant-current sources and the second constant-current source, and wherein the first constant-current source is low temperature temperature
Degree sensor power, on the basis of the second constant-current source, resistance is powered；Described constant-current source uses any commonly employed constant-current source electricity
Road, its precision does not affect measuring accuracy.
In technique scheme, the voltage at reference resistance two ends is as the reference voltage signal of A/D converter part；?
In technique scheme, no matter reference resistance, connection between cryogenic temperature sensor and constant-current source are by above-mentioned
A kind of connected mode connects or the second connected mode connects, owing to cryogenic temperature sensor passes through with reference resistance
Electric current identical, the signal that A/D converter part records is really cryogenic temperature sensor resistance value and reference resistance
The ratio of resistance value, therefore, the precision of constant-current source own has no effect on certainty of measurement；When cryogenic temperature sensor is relative
Fix, when need not often change, above-mentioned the first connect simpler；When cryogenic temperature sensor need through
When often changing, use the second connected mode more convenient.
In technique scheme, described single-chip microcomputer be AVR single chip, PIC single chip microcomputer, 51 series monolithics,
STM8 single-chip microcomputer or STM32 single-chip microcomputer.
In technique scheme, described LCDs be a segment liquid crystal display screen, LCD screen or
Color TFT-LCD display screen；Both LCDs rear are more complicated with the connected mode of single-chip microcomputer, but can show
Information is more；LCDs can also be replaced with LED charactron, but its power consumption is relatively big, service time of battery
Can shorten.
In technique scheme, described communication serial ports device is RS-232 serial ports, RS-485 serial ports or USB；As
Fruit need not export to computer data, it is also possible to omits communication serial ports device；When the communication using USB form
During serial ports, can be powered to the machine from computer by USB interface, to save battery electric power；If internal battery
When being rechargeable battery, it is also possible to by USB interface be internal battery charge.
In technique scheme, realize start, shutdown, range swithching and display by the switch being connected with single-chip microcomputer
The functions such as Conversion of measurement unit；As required, described switch can be key switch, knob or tumbler switch.
In technique scheme, the Portable low-temp thermometer complete machine that power supply stabilization circuit is the present invention provides stable
Operating voltage.Internal battery can be dry cell, rechargeable cell, lithium ion battery, ferric phosphate lithium cell or cadmium
Mercury cell.
Compared with prior art, the Portable low-temp thermometer that the present invention provides has the following technical effect that
All parts in addition to cryogenic temperature sensor are fully integrated in single machine box by the present invention, save space；
Machine volume can be accomplished less than conventional universal meter, and the sizableness such as digital camera, mobile phone, handy to carry about
Carry out rapidly measurement work；The replaceable different types of temperature sensor of the present invention, thus adapt to measure not equality of temperature
District, the demand of different determinand；The present invention can use dry cell or rechargeable battery powered, need not be outward when generally using
Connect power supply, the most convenient.Under normal measuring state, internal battery can work more than 2 hours, built-in under off-mode
Battery can keep the electric power of more than one month；The certainty of measurement of the present invention is only by reference resistance precision and A/D converter
Part precision determines, in machine, constant-current accuracy does not affect certainty of measurement；The present invention is when environment temperature 0 DEG C～40 DEG C
Normal work；When using cadmium-mercuric oxide cell, operating temperature low can reach-40 DEG C.
Accompanying drawing explanation
Below in conjunction with the accompanying drawings and embodiment further describes the present invention.
Fig. 1 is the structural representation of the present invention (embodiment 1)；
Fig. 2 is the structural representation of the present invention (embodiment 2).
Detailed description of the invention
Below in conjunction with the accompanying drawings and specific embodiment is further described through the present invention.
Embodiment 1
As it is shown in figure 1, wherein, constant-current source 1 uses discrete device to build temperature sensor 2 can for the present embodiment structure
Use PT100, PT1000, thermoelectricity occasionally rhodium-iron resistance thermometer,；Reference resistance 3 uses 0.01% grade of accurate reference resistance；
A/D converter part 4 uses 16, AD7705 type (4 the half) conversion chip of ADI company；Single-chip microcomputer 5 uses ATMEL
8 single-chip microcomputers of the ATMEGA48 type of company, can store the scale division meter data of aforementioned temperature sensor 2 inside it,
And export data by predetermined format to LCDs 8 and communication serial ports device 9；Power regulator 6 uses HOLTEK
The HT7133 type 3.3V voltage stabilizing chip of company；Internal battery 7 uses 4 No. 5 rechargeable batteries of joint being used in series；
LCDs 8 uses 4 segment liquid crystal display screens；Communication serial ports device 9 uses the MAX3232 of Maxim company
Chip, it is provided that RS-232 serial communication function；
After pressing switch 10 startup the machine, internal battery 7 provides 3.3V by power regulator 6 to single-chip microcomputer 5
Stable operating voltage, after single-chip microcomputer 5 starts work, first to constant-current source 1, A/D converter part 4, liquid crystal display 8,
Communication serial ports device 9 initializes；Afterwards, constant-current source 1 provides stable operating current to temperature sensor 2,
This electric current again passes through reference resistance 3 subsequently, and reference resistance 3 both end voltage is as the reference voltage of A/D converter part 4；
Therefore, what A/D converter part recorded is the ratio of temperature sensor 2 resistance value and reference resistance 3 resistance value.
After single-chip microcomputer 5 working stability, from A/D converter part 4, i.e. constantly read the temperature data gathered, warp
The phasing meter stored in looking into single-chip microcomputer machine, is converted into temperature value, and shows on 4 segment liquid crystal display screens 8,
Simultaneously to communication serial ports device 9 output temperature data；Again pushing button after 10, single-chip microcomputer 5 is first shut off constant current
Source 1, A/D converter part 4, liquid crystal display 8, the power supply of communication serial ports device 9, then self enters resting state.
The machine can realize, from 20K～300K (-253 DEG C～27 DEG C), being accurate to the temperature measurement function of 0.1K.
Embodiment 2
The present embodiment structure is as shown in Figure 2.Wherein temperature sensor 2 can use PT100, PT1000, thermoelectricity occasionally
Rhodium-iron resistance thermometer, etc., it is possible to pull down replacing easily；Reference resistance 3 uses 0.001% grade of precision resistance.A/D turns
Parallel operation part 4 uses 24, AD7793 type (6 the half) conversion chip of ADI company, and the first constant-current source 1 and second is permanent
Stream source 1 ' uses the special mirror-image constant flow source that AD7793 chip internal provides, it is ensured that it is completely the same that both export electric current；
Single-chip microcomputer 5 uses 32 single-chip microcomputers of STM32F103 type of ST company, can store tens of temperature sensors
Indexing data, can set with various not commensurates, form to LCDs 8 and gang up news serial ports device 9 defeated
Go out temperature data；Power regulator 6 uses the HT7133 type 3.3V voltage stabilizing chip of HOLTEK company；Internal battery
7 use a joint 800mAh lighium polymer rechargeable battery；LCDs 8 uses 122*32 LCD screen；
Communication serial ports device 9 uses the USB communication module that STM32F103 single-chip microcomputer carries；Switch 10 for key switch is
Complete machine provides switching on and shutting down, range setting, Conversion of measurement unit and calibration function.
After switch 10 startup the machine, internal battery 7 provides electric power by power regulator 6 to single-chip microcomputer 5, single
After sheet machine 5 starts work, first to first constant-current source the 1, second constant-current source 1 ', A/D converter part 4, liquid crystal
Display screen 8, serial communication device 9 initialize；Meanwhile, the first constant-current source 1 carries to cryogenic temperature sensor 2
For stable operating current, the second constant-current source 1 ' then provides identical with the first constant-current source 1 to reference resistance 3
Operating current, reference resistance 3 both end voltage is as the reference voltage of A/D converter part 4；Therefore, A/D converter
The ratio being really cryogenic temperature sensor 2 resistance value and reference resistance 3 resistance value that part 4 records.
After single-chip microcomputer 5 working stability, i.e. constantly read from A/D converter part 4 by cryogenic temperature sensor 2 institute
The temperature data gathered, the phasing meter that stores in machine looked into by single-chip microcomputer 5, it is converted into temperature value, and by setting
Unit, form show on LCDs 8, and with in/the corresponding information of English display, simultaneously to serial ports
Communication device 9 output temperature data.
During by switch 10, single-chip microcomputer 5 is changed successively by 4K～20K, 20K～100K, the order of 100K～300K
The range form of output；When pressing identity transformation key, single-chip microcomputer 5 is by thermodynamic scale K, Celsius temperature DEG C, Fahrenheit temperature
The order of degree changes the unit of display.
Single-chip microcomputer 5 the most constantly detection internal battery 7 supply voltage, aobvious on LCDs 8 during brownout
Show low electricity warning message, remind user change battery or charge for internal battery；When single-chip microcomputer 5 detects USB
After interface is connected to computer, i.e. controls power regulator 6 and charge to internal battery 7.
Again by switch 10 after, single-chip microcomputer 5 be first shut off constant-current source 1, A/D converter part 4, LCDs 8,
The power supply of communication serial ports device 9, then self enters resting state.
Time-out idle function can also be set for the machine by switch 10, after enabling this function, if it exceeds set
Time operates, and single-chip microcomputer 5 can be automatically switched off the power supply of each module, and then self enters resting state, with
Save battery electric power.
The temperature sensor interface of the machine designs for changeable type, after changing new temperature sensor, by button 10
The scale division meter data of new sensor can be set, it is also possible to by serial mode from the new sensor of computer settings point
Degrees of data.
The machine can realize, from 4K～300K (-269 DEG C～27 DEG C), being accurate to the temperature measurement function of 0.01K, than
Embodiment 1 provides more function.
It is last it should be understood that above example is only in order to illustrate technical scheme and unrestricted；To the greatest extent
The present invention has been described in detail by pipe with reference to embodiment, it will be understood by those within the art that, to this
Bright technical scheme is modified or equivalent, and without departure from the protection domain of technical solution of the present invention, it is equal
Should contain in the middle of scope of the presently claimed invention.
Claims (10)
1. a Portable low-temp temperature measuring equipment, comprising: cryogenic temperature sensor, A/D converter part,
Constant-current source, reference resistance, single-chip microcomputer, LCDs, communication serial ports device, switch, power regulator and interior
Put battery；It is characterized in that: described A/D converter part, constant-current source, reference resistance, single-chip microcomputer, communication serial ports
Device, power regulator and internal battery are placed in a casing；Described LCDs is placed in the fluting of casing, institute
State switch and draw the perforate of casing；Described cryogenic temperature sensor is placed in outside casing；
Described internal battery is respectively single-chip microcomputer and constant current source power supply after power regulator voltage stabilizing；Constant-current source is low temperature
Temperature sensor provides a stabling current；The voltage signal of cryogenic temperature sensor output turns through A/D converter part
Read by single-chip microcomputer after changing data signal into, inquire about built-in phasing meter through single-chip microcomputer and be converted to temperature value, afterwards
Display is on liquid crystal display；Or the temperature value drawn is sent to computer through communication serial ports device by single-chip microcomputer, by counting
Calculation machine embedded software realizes the record of temperature value.
2. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described low temperature temperature
Degree sensor is platinum resistance temperature sensor, carbon resistance temperature sensor, rhodium-iron resistance thermometer, temperature sensor, thermocouple
Temperature sensor or diode temperature sensor.
3. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described A/D turns
Parallel operation part is to have the A/D converter ic no less than position precision.
4. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described constant-current source,
Connected mode between cryogenic temperature sensor and reference resistance has two ways: the first is constant-current source, low temperature temperature
Degree sensor is connected by low temperature constant current source power supply with reference resistance；The second is to use two on all four first perseverances
Stream source and the second constant-current source, wherein the first constant-current source is that cryogenic temperature sensor is powered, electricity on the basis of the second constant-current source
Resistance power supply.
5. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described benchmark electricity
The voltage at resistance two ends is as the reference voltage signal of A/D converter part；The signal that A/D converter part records is really
Cryogenic temperature sensor resistance value and the ratio of reference resistance resistance value.
6. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described single-chip microcomputer
For AVR single chip, PIC single chip microcomputer, 51 series monolithics, STM8 single-chip microcomputer or STM32 single-chip microcomputer.
7. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described liquid crystal
Display screen is a segment liquid crystal display screen, LCD screen or color TFT-LCD display screen.
8. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described communication string
Mouthpart part is RS-232 serial ports, RS-485 serial ports or USB.
9. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described switch is
Key switch, knob or tumbler switch.
10. the Portable low-temp temperature measuring equipment as described in claim 1, it is characterised in that described is built-in
Battery is dry cell, rechargeable cell, lithium ion battery, ferric phosphate lithium cell or cadmium-mercuric oxide cell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310118972.6A CN104101440B (en) | 2013-04-08 | 2013-04-08 | A kind of Portable low-temp thermometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310118972.6A CN104101440B (en) | 2013-04-08 | 2013-04-08 | A kind of Portable low-temp thermometer |
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| Publication Number | Publication Date |
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| CN104101440A CN104101440A (en) | 2014-10-15 |
| CN104101440B true CN104101440B (en) | 2016-08-24 |
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| CN201310118972.6A Active CN104101440B (en) | 2013-04-08 | 2013-04-08 | A kind of Portable low-temp thermometer |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3213156A1 (en) * | 1982-04-08 | 1983-10-13 | Friedrich 7922 Herbrechtingen Hofmann | Temperature measurement device for the determination of fertile and infertile days in women |
| CN201917415U (en) * | 2010-10-26 | 2011-08-03 | 北京航天正信科技有限公司 | Outdoor type temperature acquisition module used in low-temperature environment |
| CN202048990U (en) * | 2011-03-21 | 2011-11-23 | 中国人民解放军军事医学科学院卫生装备研究所 | Stylus type temperature measuring recorder |
-
2013
- 2013-04-08 CN CN201310118972.6A patent/CN104101440B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3213156A1 (en) * | 1982-04-08 | 1983-10-13 | Friedrich 7922 Herbrechtingen Hofmann | Temperature measurement device for the determination of fertile and infertile days in women |
| CN201917415U (en) * | 2010-10-26 | 2011-08-03 | 北京航天正信科技有限公司 | Outdoor type temperature acquisition module used in low-temperature environment |
| CN202048990U (en) * | 2011-03-21 | 2011-11-23 | 中国人民解放军军事医学科学院卫生装备研究所 | Stylus type temperature measuring recorder |
Non-Patent Citations (1)
| Title |
|---|
| 多通道温度自动测量存储系统的设计与实现;程建华;《传感器与微系统》;20120820;第31卷(第8期);130-133,136 * |
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| CN104101440A (en) | 2014-10-15 |
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