CN204903669U - Tester - Google Patents
Tester Download PDFInfo
- Publication number
- CN204903669U CN204903669U CN201520479395.8U CN201520479395U CN204903669U CN 204903669 U CN204903669 U CN 204903669U CN 201520479395 U CN201520479395 U CN 201520479395U CN 204903669 U CN204903669 U CN 204903669U
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- Prior art keywords
- high internal
- internal resistance
- analog
- digital converter
- code translator
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Abstract
The utility model discloses a tester, load first high internal resistance voltmeter and the high internal resistance voltmeter of second in the shell, when using different measurement mode to measure the thermal resistance, mode in order to correspond inserts the return circuit with the probe, the demonstration is changed respectively through first high internal resistance voltmeter and the high internal resistance voltmeter of second to the current potential that records, supply operating personnel to read the magnitude of voltage of two display screens, and the size of foundation two magnitude of voltages of surveying, having it's too late, correlation finds out the position of fault point, only need to insert the just non -destructive fault point position of judging fast of return circuit.
Description
Technical field
The utility model relates to electronic technology field, particularly relates to a kind of pick-up unit.
Background technology
In industrial processes, the physical parameter that temperature one is very important, the detection and control of temperature directly and the important technical economic target such as safety in production, product quality, production efficiency, economize energy be associated, therefore temperature detection class instrument, as temperature measuring tool, is also used widely.
Thermistor Temperature Measurement principle utilizes its resistance value variation with temperature and changes temperature sensor Temperature Quantity being converted to resistance that this principle makes.Thermistor Temperature Measurement primary circuit is exactly R/V change-over circuit, and resistance value is converted to corresponding voltage.I.e. U=f (R).Resistance/voltage conversion circuit has two kinds of basic transition forms, i.e. unbalanced bridge/voltage conversion circuit and constant current source resistance/voltage conversion circuit.Below for constant current source resistance/voltage conversion circuit, resistance/voltage transitions principle is described.
Temperature transmitter is by applying a known excitation constant current source to thermal resistance, the method measuring its both end voltage obtains resistance value (voltage/current), then converts resistance value to temperature value, thus realizes temperature survey.Three kinds of modes of connection are had: two-wire system, three-wire system, four-wire system between thermal resistance and temperature transmitter.
Two-line measurement mode, as Fig. 1.Transmitter applies excitation constant current source I by wire L1, L2 to thermal resistance, records electromotive force U.Wherein: thermal resistance Rt, R
l1for wire L1 equivalent resistance, R
l2for wire L2 equivalent resistance.
Under two-wire system mode, thermal resistance Rt, R
l1for wire L1 equivalent resistance, R
l2for wire L2 equivalent resistance, R
l3for wire L3 equivalent resistance.
Amplifier input differential voltage:
U＝(2RL+Rt)I
Rt＝U/I—2RL
Because resistance RL1, RL2 of connecting wire cannot record, and be counted in the resistance value of thermal resistance, make measurement result produce additive error.Such as 100 DEG C time the thermal resistance rate of Pt100 thermal resistance be 0.385 Ω/DEG C, if at this moment the resistance value of wire is 2 Ω, then the measuring error that can cause is 5.2 DEG C.
U＝(2RL+Rt)I
Rt＝U/I—2RL
Three-wire system metering system is modal connection in practical application.As Fig. 2, increase the measuring error that a wire causes in order to the resistance compensating connection wire.Three-wire system requires that the material of three wires, wire diameter, length are consistent and working temperature is identical, makes the resistance value of three wires identical, i.e. RL1=RL2=RL3.Apply excitation constant current source I by wire L1, L2 to thermal resistance, apply another excitation constant current source I by wire L2, L3, record electromotive force U.
Under three-wire system metering system, because two constant current source electric currents are equal and be known as I, so according to superposition theorem, amplifier input differential voltage:
U＝[(2IRL)+(Rt+RL)I]-(2IRL+IRt)＝IRt
Rt＝U/I
When adopting three-wire system metering system, the electric current of these two constant current sources and the line resistance at thermal resistance two ends, often always can not be completely equal.There is a small amount of error, thus line resistance can not be offset completely, but can meet the demands in certain accuracy rating. three-wire system connection can be obtained thus, the measuring error that the resistance that can compensate connection wire causes.
Four-line measurement mode is the desirable mode of connection of Thermistor Temperature Measurement.As Fig. 3, apply excitation constant current source I by wire L1, L4 to thermal resistance, record electromotive force U.Wire L2, L3 access high input impedance circuit, and its loop current is zero.
Under four-line measurement mode, thermal resistance Rt, R
l1for wire L1 equivalent resistance, R
l2for wire L2 equivalent resistance, R
l3for wire L3 equivalent resistance, R
l4for wire L4 equivalent resistance.
Amplifier input differential voltage:
U＝IRt
Rt＝U/I
Four-wire measurement two additional testing lines provide steady current, another two p-wires measure the voltage drop of unknown resistance, in the internal resistance of voltage table or under measuring the sufficiently high condition of amplifier input impedance, its loop current is zero, this just accurately can measure the pressure drop U on unknown resistance, again divided by current known I, thermal resistance resistance Rt can be drawn, and no matter whether much the and each section line resistances of line are equal in theory all has nothing to do with measuring accuracy, four-line measurement mode is by the impact of resistance connecting wire.
But, two-wire system, three-wire system, four-wire system mode no matter is adopted to measure thermal resistance, along with the impact of the factor such as aging circuit, variation of ambient temperature, thermal resistance, line resistance and intermediate terminal line bank all can break down, but Thermistor Temperature Measurement point is all away from measuring instrument, it is longer that it measures primary circuit circuit, and have multiple intermediate terminal line bank, therefore investigate trouble spot very difficult, also do not find at present suitable mode can fast, Non-Destructive Testing is out of order a little.
Utility model content
The utility model provides a kind of pick-up unit, to solve the very difficult technical matters in prior art investigation trouble spot.
For solving the problems of the technologies described above, the utility model provides a kind of pick-up unit, specifically for detecting trouble spot, thermal resistance temperature surveying primary circuit, comprising:
Shell, is mounted with the first high internal resistance voltage table and the second high internal resistance voltage table in described shell;
Described first high internal resistance voltage table comprises:
First operational amplifier, comprises the first in-phase input end, the first reverse input end, the first output terminal; Wherein, described first in-phase input end, described first inverting input access two probes respectively;
First analog to digital converter, the first end of described first analog to digital converter connects described first output terminal;
First code translator, the first end of described first code translator connects the second end of described first analog to digital converter, and the second end of described first code translator connects the first display screen;
Described second high internal resistance voltage table comprises:
Second operational amplifier, comprises the second in-phase input end, the second reverse input end, the second output terminal; Wherein, described second in-phase input end, described second inverting input access two probes respectively;
Second analog to digital converter, the first end of described second analog to digital converter connects described second output terminal;
Second code translator, the first end of described second code translator connects the second end of described second analog to digital converter, and the second end of described second code translator connects second display screen.
Preferably, described shell is also provided with litter and N number of slide block, described N number of slide block can move on described litter, described N be more than or equal to 2 positive integer.
By one or more technical scheme of the present utility model, the utility model has following beneficial effect or advantage:
The utility model discloses a kind of pick-up unit, the first high internal resistance voltage table and the second high internal resistance voltage table is loaded in shell, when using different metering systems to measure thermal resistance, in a corresponding way probe is accessed loop, the electromotive force recorded is by changing display respectively by the first high internal resistance voltage table and the second high internal resistance voltage table, the magnitude of voltage of two display screens is read for operating personnel, and survey the size of two magnitudes of voltage, the mutual relationship that has that it's too late to find out the position of trouble spot according to institute, need to access loop just can quick nondestructive judge position of failure point.
Accompanying drawing explanation
The two-line measurement schematic diagram that Fig. 1 provides for prior art;
The three-wire system instrumentation plan that Fig. 2 provides for prior art;
The four-line measurement schematic diagram that Fig. 3 provides for prior art;
The schematic diagram of the pick-up unit that Fig. 4 provides for the utility model embodiment;
The schematic diagram in the pick-up unit access loop that Fig. 5 provides for the utility model embodiment.
Description of reference numerals: shell 01, the high internal resistance voltage table 03 of the first high internal resistance voltage table 02, second, litter 04, slide block 05, the first operational amplifier 21, first analog to digital converter 22, first code translator 23, first display screen 24, second operational amplifier 31, second analog to digital converter 32, second code translator 33, second display screen 34.
Embodiment
In order to make the utility model the technical staff in the technical field more clearly understand the utility model, below in conjunction with accompanying drawing, by specific embodiment, technical solutions of the utility model are described in detail.
The utility model embodiment provides a kind of pick-up unit, specifically for detecting trouble spot, thermal resistance temperature surveying primary circuit.
See Fig. 4, the pick-up unit in the present embodiment comprises:
Shell 01, is mounted with the first high internal resistance voltage table 02 and the second high internal resistance voltage table 03 in shell 01; And shell 01 is provided with litter 04 and N number of slide block 05, described N number of slide block 05 can move on described litter 04, described N be more than or equal to 2 positive integer.In the present embodiment, employ 3 slide blocks 05, the fundamental purpose arranging slide block 05 is that the relative position of terminal block in order to make access probe is adjustable, because the size of the terminal of terminal block is had nothing in common with each other, make its respective position adjustable, in order to avoid affect testing result because being employed herein slide block 05.
Lower mask body introduces the first high internal resistance voltage table 02 and the second high internal resistance voltage table 03.
Described first high internal resistance voltage table 02 comprises:
First operational amplifier 21, comprises the first in-phase input end, the first reverse input end, the first output terminal; Wherein, described first in-phase input end, described first inverting input access two probes respectively;
First analog to digital converter 22, the first end of described first analog to digital converter 22 connects described first output terminal;
First code translator 23, the first end of described first code translator 23 connects the second end of described first analog to digital converter 22, and the second end of described first code translator 23 connects described first display screen 24.
See Fig. 4, be accessed probe for three-wire system, wherein, the first in-phase input end has accessed probe 3, and the first reverse input end has accessed probe 1.And after the conversion of the electromotive force U1 recorded by the first operational amplifier 21, first analog to digital converter 22, first code translator 23, will be presented on the first display screen 24.And on the first display screen 24, can show in the mode of voltage, also can show in the mode of temperature.
Described second high internal resistance voltage table 03 comprises:
Second operational amplifier 31, comprises the second in-phase input end, the second reverse input end, the second output terminal; Wherein, described second in-phase input end, described second inverting input access two probes respectively;
Second analog to digital converter 32, the first end of described second analog to digital converter 32 connects described second output terminal;
Second code translator 33, the first end of described second code translator 33 connects the second end of described second analog to digital converter 32, and the second end of described second code translator 33 connects described second display screen 34.
Continue see Fig. 4, be accessed probe for three-wire system, wherein, the second in-phase input end has accessed probe 2, and the second reverse input end and the first reverse input end have accessed probe 1 in the lump.And after the conversion of the electromotive force U2 recorded by the second operational amplifier 31, second analog to digital converter 32, second code translator 33, will be presented on second display screen 34.And on second display screen 34, and the first display screen 24 is similar, can show in the mode of voltage, also can show in the mode of temperature.
If be shown as example with voltage, probe can be contacted with circuit or intermediate terminal line bank, read the magnitude of voltage of two display screens, according to survey the size of two magnitudes of voltage, the mutual relationship that has that it's too late to find out the position of trouble spot.
The connected mode of this device and thermal resistance temperature surveying primary circuit when lower mask body introduces two-wire system, three-wire system, four-wire system.
If two-wire system, then two probe access loops in first of this pick-up unit the high internal resistance voltage table 02 can be used to measure; Or use two probe access loops in the second high internal resistance voltage table 03 to measure.
If three-wire system, then access loop in the mode of Fig. 4.Concrete connection diagram please refer to Fig. 5.There is terminal block 1 in the loop ... terminal block N.And pick-up unit is connected with terminal block N correspondence.Probe is contacted with corresponding terminal block, then can read the magnitude of voltage of two display screens, and according to survey the size of two magnitudes of voltage, the mutual relationship that has that it's too late to find out the position of trouble spot.Further, only the trouble spot once then can judging loop need be accessed.Such as by access terminal block N, just can judge concrete trouble spot, such as, thermal resistance damage, circuit damage or terminal block damage etc., and need not access actual fault point carry out detections judgement.
If four-wire system, then the mode of three-wire system is used to measure twice.
In actual load process, first press the circuit block diagram of accompanying drawing 4, make circuit with microminiaturization, and adjust circuit, power acquisition compact battery is power supply, carries out electromagnetic screen, whole device is placed in the box of shell 01, and installs the probe of probe, make whole device Portable miniature.
By one or more technical scheme of the present utility model, the utility model has following beneficial effect or advantage:
The utility model discloses a kind of pick-up unit, the first high internal resistance voltage table and the second high internal resistance voltage table is loaded in shell, when using different metering systems to measure thermal resistance, in a corresponding way probe is accessed loop, the electromotive force recorded is by changing display respectively by the first high internal resistance voltage table and the second high internal resistance voltage table, the magnitude of voltage of two display screens is read for operating personnel, and survey the size of two magnitudes of voltage, the mutual relationship that has that it's too late to find out the position of trouble spot according to institute, need to access loop just can quick nondestructive judge position of failure point.
Although described preferred embodiment of the present utility model, one of ordinary skilled in the art once obtain the basic creative concept of cicada, then can make other change and amendment to these embodiments.So claims are intended to be interpreted as comprising preferred embodiment and falling into all changes and the amendment of the utility model scope.
Obviously, those skilled in the art can carry out various change and modification to the utility model and not depart from spirit and scope of the present utility model.Like this, if these amendments of the present utility model and modification belong within the scope of the utility model claim and equivalent technologies thereof, then the utility model is also intended to comprise these change and modification.
Claims (2)
1. a pick-up unit, for detecting trouble spot, thermal resistance temperature surveying primary circuit, is characterized in that, comprise:
Shell, is mounted with the first high internal resistance voltage table and the second high internal resistance voltage table in described shell;
Described first high internal resistance voltage table comprises:
First operational amplifier, comprises the first in-phase input end, the first reverse input end, the first output terminal; Wherein, described first in-phase input end, described first inverting input access two probes respectively;
First analog to digital converter, the first end of described first analog to digital converter connects described first output terminal;
First code translator, the first end of described first code translator connects the second end of described first analog to digital converter, and the second end of described first code translator connects the first display screen;
Described second high internal resistance voltage table comprises:
Second operational amplifier, comprises the second in-phase input end, the second reverse input end, the second output terminal; Wherein, described second in-phase input end, described second inverting input access two probes respectively;
Second analog to digital converter, the first end of described second analog to digital converter connects described second output terminal;
Second code translator, the first end of described second code translator connects the second end of described second analog to digital converter, and the second end of described second code translator connects second display screen.
2. pick-up unit as claimed in claim 1, it is characterized in that, described shell is also provided with litter and N number of slide block, described N number of slide block can move on described litter, described N be more than or equal to 2 positive integer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520479395.8U CN204903669U (en) | 2015-07-06 | 2015-07-06 | Tester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520479395.8U CN204903669U (en) | 2015-07-06 | 2015-07-06 | Tester |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204903669U true CN204903669U (en) | 2015-12-23 |
Family
ID=54925836
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520479395.8U Expired - Fee Related CN204903669U (en) | 2015-07-06 | 2015-07-06 | Tester |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204903669U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108775972A (en) * | 2018-04-17 | 2018-11-09 | 上海船舶运输科学研究所 | The fault detection circuit of thermistor temperature detecting circuit |
-
2015
- 2015-07-06 CN CN201520479395.8U patent/CN204903669U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108775972A (en) * | 2018-04-17 | 2018-11-09 | 上海船舶运输科学研究所 | The fault detection circuit of thermistor temperature detecting circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20170707 Address after: 430080 Qingshan District stock company of Hubei, Wuhan Province Patentee after: Wuhan iron and Steel Company Limited Address before: 430080 Friendship Avenue, Hubei, Wuhan, No. 999 Patentee before: Wuhan Iron & Steel (Group) Corp. |
|
| TR01 | Transfer of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20151223 Termination date: 20200706 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |