CN201311329Y - Intelligent temperature isolating transmitter - Google Patents
Intelligent temperature isolating transmitter Download PDFInfo
- Publication number
- CN201311329Y CN201311329Y CNU2008202315612U CN200820231561U CN201311329Y CN 201311329 Y CN201311329 Y CN 201311329Y CN U2008202315612 U CNU2008202315612 U CN U2008202315612U CN 200820231561 U CN200820231561 U CN 200820231561U CN 201311329 Y CN201311329 Y CN 201311329Y
- Authority
- CN
- China
- Prior art keywords
- temperature
- conductor
- intelligent temperature
- voltage
- temperature sensor
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000004020 conductor Substances 0.000 claims abstract description 16
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 15
- 238000002955 isolation Methods 0.000 claims description 10
- 238000005259 measurement Methods 0.000 abstract description 4
- 238000000034 method Methods 0.000 abstract description 3
- 230000005540 biological transmission Effects 0.000 abstract 1
- 238000009529 body temperature measurement Methods 0.000 abstract 1
- 238000000691 measurement method Methods 0.000 abstract 1
- 238000005070 sampling Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
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- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
An intelligent temperature isolating transmitter is applied in industrial fields, and is a measurement gauge with both temperature measurement function and isolating transmission function. A temperature sensor employs Pt100 platinum resistance, and adopts a three-wire measurement method of a constant-current power conductor, a compensating conductor and an earth conductor which are connected in high-potential method called high-side compensating conductor connection method for short, wherein the compensating conductor is connected with a power terminal of the Pt100 platinum resistance to realize accurate compensation and less measurement error. The intelligent temperature isolating transmitter simultaneously employs four keys to digitally correct zero full scale, and stores set calibration value in self flash memory space of a microcontroller, thereby avoiding zero drift and temperature drift.
Description
Technical field
The utility model relates to a kind of measurement instrument that had not only had temperature survey but also had the isolation transmit function.
Background technology
In modern industry is produced, temperature be industry spot with the most use wait upon the survey physical quantity.Platinum resistance is a sensor commonly used in the thermometric, is used as the 0-926 ℃ of international standard thermometer in the humidity province.Although temperature transmitter is a lot, there is weak point to a certain extent in the temperature transmitter of other type:
1, in measurement, the caused error of connection resistances is very important, can adopt three-wire system to measure usually, but the compensating wire of other type temperature transmitter is connected on cold end usually, is called for short the ground end, causes compensation precision low, and measuring error increases.
2, adopt potentiometer to carry out zero point or full scale calibration,, make temperature transmitter that inevitable zero point drift and temperature drift take place because employed potentiometer is bigger with temperature variation in time.
Summary of the invention
The utility model proposes improvement project at the deficiency of above-mentioned other type products, develops a kind of intelligent temperature isolation transmitter.
The technical solution of the utility model is as follows: adopt three-wire system to measure, i.e. constant current electric power conductor, compensating wire and ground wire, be provided with temperature sensor, LED charactron, DC-DC insulating power supply, the input of DC24V voltage, single-chip microcomputer is characterized in that: compensating wire is connected on the temperature sensor power end; The constant current electric power conductor is connected with temperature sensor, and 24 AD ALT-CH alternate channels of the two-way of single-chip microcomputer itself are connected with constant current electric power conductor, compensating wire respectively; Single-chip microcomputer is connected to photoelectric isolating device, is connected to V/I current-to-voltage convertor spare, is connected to the DC4mA-20mA delivery outlet; Be provided with " SET " that carry out zero point, full scale calibration, "+", "-", " STORE " 4 buttons.
The beneficial effects of the utility model are: adopt the method for attachment of high-end compensating wire, can realize accurate compensation, measuring error is little.Utilize 4 buttons to carry out full scale digital calibration at zero point, and the flash memory space that utilizes C8051F350CPU to carry directly stores the setting calibration value, avoided zero point drift and temperature drift.
Description of drawings
Fig. 1 is the intelligent temperature isolation transmitter theory diagram.
Fig. 2 is low end compensating connection sketch.
Embodiment
The little principle of high end compensating connection measuring error is: in Fig. 1, utilize the DA mapping function of C8051F350CPU that intelligent temperature isolation transmitter adopts (single-chip microcomputer), directly output constant current, supply with the Pt100 platinum resistance temperature sensor, A is the constant current electric power conductor, and B is a compensating wire, and C is a ground wire, compensating wire is connected on Pt100 platinum resistance power end, promptly high-end D point.If the resistance of lead A, B, C lead is R, the resistance of platinum resistance is R
Pt, constant current is I, then the voltage of AD0 is V
A1, the voltage of AD1 is V
B1
Among Fig. 1, V
B1Voltage swing, the voltage sum that voltage that is produced by the Pt100 platinum resistance and C conductor resistance produce.V
A1The voltage sum that produced of the voltage swing voltage, A conductor resistance and the C conductor resistance that then produce by the Pt100 platinum resistance.As long as therefore utilize formula 1, just can obtain the voltage V that the Pt100 platinum resistance is produced easily
Pt
V
Pt=V
B1-(V
A1-V
B1) (formula 1)
＝2V
B1-V
A1
＝2I(R
Pt+R)-(IR
Pt+R+R)
＝IR
Pt
V among Fig. 2
A2Voltage and the V among Fig. 1
A1Voltage identical, but V
B2Voltage only produce by the resistance of C lead.Like this, the voltage V that produced of Pt100 platinum resistance
Pt
V '
Pt=V
A-2V
B(formula 2)
＝I(R+R
Pt+R)-2IR
＝IR
Pt
In theory, the voltage V that produced of the Pt100 platinum resistance of Fig. 1 Fig. 2
PtValue is the same, but in fact has significantly difference.Reason is, no matter to modulate circuit, or the AD converting unit, all there is dead band voltage problem (being the dead band).If signal is less, be near the dead band, then measure and certainly exist error.The V among Fig. 2 for example
B2Voltage is only produced by the resistance of C lead, because the resistance of lead own is less, thereby the voltage signal that is produced is also less, therefore in fact is difficult to accomplish full remuneration.On the contrary, adopt the high end compensating connection that the present invention gave, voltage V
A1, V
B1In all comprised the voltage that the Pt100 platinum resistance is produced, therefore do not exist signal than minor issue, the influence of conductor resistance of having we can say full remuneration.
This intelligent temperature isolation transmitter, adopt C8051F350CPU, DA constant current (the output current size is DC0-2mA) the output translation function of utilizing CPU itself to carry, directly as the constant current signal that encourages the Pt100 platinum resistance, the output current size of software programmable, can carry out the corresponding digital adjustment with different temperature-measuring ranges, the voltage range that the full scale voltage signal that the Pt100 platinum resistance is produced just in time meets the AD sampling obtains maximum sampling resolution.Avoid adopting peripheral constant-current circuit, save cost.
Utilize 24 AD ALT-CH alternate channels of two-way of C8051F350CPU itself respectively, according to Fig. 1 wiring.Because of the AD ALT-CH alternate channel of C8051F350CPU, variable gain (PGA) amplifying unit is contained in inside, can be to the direct V of voltage
A1, V
B1Sample, utilize formula 1 to carry out digital computation by software.
Utilize width modulation (PWM) function of the programmable count array of C8051F350CPU, adopt width modulation, utilize photoelectric isolating device to send the DC4-20mA signal of isolation.
As shown in Figure 1, utilize 4 buttons " SET ", "+", "-", " STORE " carries out the calibration of zero point, full scale by software and utilize that 4 buttons export zero point, DC4mA and full scale DC20mA were provided with.
Utilize two LED charactrons to carry out timesharing displays temperature value, also can show constant current output valve, Pt100 resistance and wire resistance value.
Claims (3)
1, a kind of intelligent temperature isolation transmitter adopts three-wire system to measure, i.e. constant current electric power conductor, compensating wire and ground wire, be provided with temperature sensor, LED charactron, DC-DC insulating power supply, the input of DC24V voltage, single-chip microcomputer is characterized in that: compensating wire is connected on the temperature sensor power end; The constant current electric power conductor is connected with temperature sensor, and 24 AD ALT-CH alternate channels of the two-way of single-chip microcomputer itself are connected with constant current electric power conductor, compensating wire respectively; Single-chip microcomputer is connected to photoelectric isolating device, is connected to V/I current-to-voltage convertor spare, is connected to the DC4mA-20mA delivery outlet; Be provided with " SET " that carry out zero point, full scale calibration, "+", "-", " STORE " 4 buttons.
2, intelligent temperature isolation transmitter as claimed in claim 1 is characterized in that: temperature sensor is the Pt100 platinum resistance.
3, intelligent temperature isolation transmitter as claimed in claim 1 is characterized in that: described single-chip microcomputer is C8051F350CPU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008202315612U CN201311329Y (en) | 2008-12-09 | 2008-12-09 | Intelligent temperature isolating transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008202315612U CN201311329Y (en) | 2008-12-09 | 2008-12-09 | Intelligent temperature isolating transmitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201311329Y true CN201311329Y (en) | 2009-09-16 |
Family
ID=41108585
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008202315612U Expired - Fee Related CN201311329Y (en) | 2008-12-09 | 2008-12-09 | Intelligent temperature isolating transmitter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201311329Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101419098B (en) * | 2008-12-09 | 2011-11-30 | 大连工业大学 | intelligent temperature isolation transmitter |
| CN104316209A (en) * | 2014-11-18 | 2015-01-28 | 吉林大学 | Aircraft engine inlet temperature measuring device and measuring method thereof |
| CN107145095A (en) * | 2016-03-01 | 2017-09-08 | 四川中泽电子有限公司 | A kind of liquid nitrogen container temperature monitoring system |
| CN111103010A (en) * | 2018-12-27 | 2020-05-05 | 冯丽雅 | Portable digital display hygrothermograph |
-
2008
- 2008-12-09 CN CNU2008202315612U patent/CN201311329Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101419098B (en) * | 2008-12-09 | 2011-11-30 | 大连工业大学 | intelligent temperature isolation transmitter |
| CN104316209A (en) * | 2014-11-18 | 2015-01-28 | 吉林大学 | Aircraft engine inlet temperature measuring device and measuring method thereof |
| CN107145095A (en) * | 2016-03-01 | 2017-09-08 | 四川中泽电子有限公司 | A kind of liquid nitrogen container temperature monitoring system |
| CN111103010A (en) * | 2018-12-27 | 2020-05-05 | 冯丽雅 | Portable digital display hygrothermograph |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090916 Termination date: 20101209 |