CN206258503U - A kind of current collector of two-wire system sensor - Google Patents
A kind of current collector of two-wire system sensor Download PDFInfo
- Publication number
- CN206258503U CN206258503U CN201621206325.6U CN201621206325U CN206258503U CN 206258503 U CN206258503 U CN 206258503U CN 201621206325 U CN201621206325 U CN 201621206325U CN 206258503 U CN206258503 U CN 206258503U
- Authority
- CN
- China
- Prior art keywords
- resistance
- resistor
- output end
- wire system
- system sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Measurement Of Current Or Voltage (AREA)
Abstract
The utility model is related to a kind of current collector of two-wire system sensor, including precision resistance and operational amplifier, precision resistance to be connected between the first output end and input；Positive pole in the voltage signal at precision resistance two ends is connected with one end of first resistor, negative pole ground connection；The other end of first resistor is connected with the normal phase input end of operational amplifier, and the other end of first resistor is also connected by second resistance with the second output end；The inverting input of operational amplifier is directly grounded, and output end is connected with one end of sampling resistor；The other end of the sampling resistor is connected with the second output end；One end of the sampling resistor is also directly grounded；The resistance of the precision resistance is much smaller than the first resistor and the resistance of second resistance.The utility model makes a current signal for sensor be used for two measuring instruments in the case of without being modified to measuring instrument.
Description
Technical field
The utility model is related to current acquisition technical field, more particularly to a kind of current acquisition of two-wire system sensor
Device.
Background technology
At present, most of sensors all develop to two-wire system, and the use of two-wire system sensor is more and more extensive.Due to two wires
The both threads that sensor processed is drawn are both power line and holding wire, so the both threads that many measuring instruments are drawn all provide biography
Voltage needed for sense device working, can directly connect on a sensor.It is expensive due to sensor, it is sometimes desirable to reduce as far as possible
The quantity of sensor, also has some special circumstances, it is necessary to gather an electric current for sensor simultaneously with two measuring instruments.Due to
Two measuring instruments working sensor is all provided needed for voltage, this causes that measuring instrument encounters difficulties with the connection of sensor.
In the market using it is more be one to enter two signal isolators for going out, it makes the electric current that sensor is exported while being divided into two-way.
But, needing to remove the voltage that measuring instrument is provided using signal isolator, this needs to change the circuit inside measuring instrument,
Comparatively laborious, some measuring instrument internal structures are complicated, and modification circuit may cause to damage to measuring instrument.Accordingly, it would be desirable to one
Plant the device that a sensor can be made to be used for the measuring instruments of two offer voltages.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of current collector of two-wire system sensor, without
A current signal for sensor is set to be used for two measuring instruments in the case of being modified to measuring instrument.
The utility model solves the technical scheme that its technical problem used：A kind of electric current of two-wire system sensor is provided
Collector, including precision resistance and operational amplifier, the precision resistance are connected on first for the first measuring instrument of connection
Output end and between the input for connecting two-wire system sensor, for the current signal of two-wire system sensor to be converted into electricity
Pressure signal；Positive pole in the voltage signal at the precision resistance two ends is connected with one end of first resistor, negative pole ground connection；Described
The other end of one resistance is connected with the normal phase input end of the operational amplifier, and the other end of the first resistor also passes through second
Resistance is connected with for being connected the second output end of the second measuring instrument；The inverting input of the operational amplifier directly connects
Ground, output end is connected with one end of sampling resistor；The other end of the sampling resistor is connected with the second output end；The sampling electricity
One end of resistance is also directly grounded；The resistance of the precision resistance is much smaller than the first resistor and the resistance of second resistance.
The resistance of the sampling resistor is equal with the resistance of the precision resistance.
The output end of the operational amplifier is also associated with negative-feedback circuit；The negative-feedback circuit includes triode, institute
State the base stage of triode to be connected with the output end of operational amplifier, emitter stage is by 3rd resistor ground connection, colelctor electrode and power end
It is connected.
Current-limiting resistance and voltage-regulator diode, the current limliting electricity are also in series between the output end and ground of the operational amplifier
Base stage of the connection end of resistance and voltage-regulator diode also with the triode is connected.
First output end and the second output end are equipped with a full-bridge rectifier.
First output end and the second output end are equipped with decoupling capacitance.
The two ends of the decoupling capacitance are also parallel with TVS pipe.
Beneficial effect
As a result of above-mentioned technical scheme, the utility model compared with prior art, has the following advantages that and accumulates
Pole effect：The utility model passes one in the case where two measuring instruments all provide the operating voltage of two-wire system sensor
The output current of sensor is divided into two-way while used for two measuring instruments, and the electric current that collects of two measuring instruments with it is original
Size of current in sensor is identical.One is in particular cases gathered simultaneously with two different measuring instruments this satisfies some
The requirement of the electric current in sensor, also saves the use number of sensor, reduces cost.The device circuit simple structure,
It is cheap, error very little.
Brief description of the drawings
Fig. 1 is circuit diagram of the present utility model；
Fig. 2 is connection diagram when the utility model is used.
Specific embodiment
With reference to specific embodiment, the utility model is expanded on further.It should be understood that these embodiments are merely to illustrate this
Utility model rather than limitation scope of the present utility model.In addition, it is to be understood that reading the content of the utility model instruction
Afterwards, those skilled in the art can make various changes or modifications to the utility model, and these equivalent form of values equally fall within this Shen
Please appended claims limited range.
Implementation method of the present utility model is related to a kind of current collector of two-wire system sensor, as shown in figure 1, including essence
Cipher telegram hinders RcAnd operational amplifier, the precision resistance be connected on for connect the first measuring instrument 1 the first output end and use
Between the input of connection two-wire system sensor, for the current signal of two-wire system sensor to be converted into voltage signal；Institute
State precision resistance RcPositive pole and first resistor R in the voltage signal at two ends1One end be connected, negative pole ground connection；The first resistor
R1The other end be connected with the normal phase input end of the operational amplifier, the first resistor R1The other end also by second electricity
Resistance R2It is connected with for being connected the second output end of the second measuring instrument 2；The inverting input of the operational amplifier directly connects
Ground, output end and sampling resistor RsOne end be connected；The sampling resistor RsThe other end be connected with the second output end；It is described to adopt
Sample resistance RsOne end be also directly grounded；The precision resistance RcResistance be much smaller than the first resistor R1With second resistance
Resistance R2。
As can be seen here, connected in connection circuit of the measuring instrument 1 with sensor a precision resistance of 150 Ω, will passed
Electric current in sensor is changed into voltage.The positive polarity is connected on first resistor R1On, negative pole ground connection.By first resistor R1With
Two resistance R2" empty short " of the larger resistance of two resistances and operational amplifier and " void is disconnected " characteristic by B points voltage pull-down to-
V0, so passes through sampling resistor RsIn electric current it is just identical with the size of current in sensor, and with sensor export electricity
The change of stream and change.
The output end of the operational amplifier is also associated with negative-feedback circuit；The negative-feedback circuit includes triode Q1,
The base stage of the triode Q1 is connected with the output end of operational amplifier, and emitter stage passes through 3rd resistor ReGround connection, colelctor electrode with
Power end is connected.Current-limiting resistance R is also in series between the output end and ground of the operational amplifiermWith voltage-regulator diode Z1, it is described
Current-limiting resistance RmWith voltage-regulator diode Z1Base stage of the connection end also with triode Q1 be connected.
Triode Q1 is added for the voltage for preventing operational amplifier normal phase input end is raised and lowered suddenly, in circuit to be carried out
Feedback regulation, it is ensured that A points magnitude of voltage is 0.Current-limiting resistance RmWith voltage-regulator diode Z1The base voltage of triode Q1 can also be avoided
It is excessive.
First output end and the second output end are equipped with a full-bridge rectifier so that when measuring instrument is reversed still
Can normal work.First output end and the second output end are equipped with decoupling capacitance C1And C2, decoupling capacitance C1And C2Can protect
Circuit does not shake under demonstrate,proving long-term inductive load.The two ends of the decoupling capacitance are also parallel with TVS pipe Z2And Z3, TVS pipe Z2And Z3Can
To absorb the energy of moment overvoltage, prevent the energy such as thunderbolt, static discharge, surge from damaging current splitters.
Fig. 2 is connection diagram when the utility model is used.Wherein, IN3, OU3 end of current separation device respectively with
The positive and negative terminal of two-wire system sensor is connected, the IN1 ends of current separation device and OUT1 ends respectively with the+24V of measurement apparatus 1 with
GND ends are connected, and the IN2 ends of current separation device are connected with+24V and the GND end of measurement apparatus 2 respectively with OUT2 ends.
Next combine Fig. 1 and illustrate the course of work of the present utility model, in Fig. 1, first resistor R1, second resistance R2, current limliting
Resistance Rm, 3rd resistor Re, precision resistance Rc, sampling resistor RsChromatic circle resistance is used, wherein, first resistor R1, second resistance
R2, current-limiting resistance Rm, 3rd resistor ReResistance precision be 1%, precision resistance Rc, sampling resistor RsUsing the high-accuracy metals of RJ24
Film resistor, precision is 0.1%.Operational amplifier uses LM358 or LM324 amplifier chips.Current-limiting resistance Rm, voltage-regulator diode
Z1It is 1N4735, the base voltage of triode Q1 can be avoided excessive.Decoupling capacitance C1And C2It is 10nF, it is ensured that long-term perception
The lower circuit of load does not shake.The input of two measuring instruments has a full-bridge rectifier, even if measuring instrument is reversed remaining to
Normal work.TVS pipe Z2And Z3The energy of moment overvoltage can be absorbed, prevents the energy such as thunderbolt, static discharge, surge from damaging electricity
Stream separator.
Measuring instrument 1 is connected with sensor first, and the electric current flowed through in sensor is Ic, by precision resistance RcBy electric current
Signal is converted to voltage signal V0, below analysis voltage signal V0It is changed into electric current I2Process：
Precision resistance R firstcThe voltage for collecting is V0, flow through first resistor R1Electric current I1=V0/R1, because computing is put
The input of big device can not possibly absorb electric current, then electric current I1All flow through second resistance R2, then B point voltages VB=-I1*R2=-
V0*R2/R1, take R1=R2When, there is VB=-V0。
There was only sampling resistor R between the negative terminal of measuring instrument 2 and whole transmitter circuitsWith second resistance R2, therefore it is all of
Electric current all flows through sampling resistor RsWith second resistance R2.Second resistance R2Upper end is virtual earth (0V), sampling resistor RsUpper end is GND.
Therefore second resistance R2With sampling resistor RsBoth end voltage is just the same, is equal to voltage VB, equivalent to sampling resistor RsWith second
Resistance R2Parallel connection is used as current sampling resistor.Therefore circuit total current I2=V0/(Rs//R2), if taking R2＞ ＞ Rs, then I2=
V0/Rs.Therefore, R is takens=RcWhen, I2With IcSize is identical.If R can not be met2＞ ＞ RsAlso have no relations, sampling resistor RsWith second
Resistance R2(Rs//R2) it is a fixed value, electric current IsWith voltage V0It is still linear relationship, error rate coefficient can be with calibration
Eliminate.
In order to ensure A point voltages remain 0V, negative-feedback circuit is added.Lower surface analysis negative feedback process：If A points because
Certain reason is higher than 0V, then the output of 1 point of operational amplifier is raised, 3rd resistor ReBoth end voltage is raised, by 3rd resistor Re
Electric current become big.By sampling resistor RsElectric current also become big, B point voltages step-down (negative more).Result is by second resistance R2
A point voltages are pulled down.If conversely, A points are less than 0V because of certain reason, also 0V can be raised back by negative-feedback circuit.In a word, bear anti-
The result of current feed circuit keeps empty short, the i.e. A points voltage=0V of operational amplifier.
In addition to circuit is correct, the circuit normal work also require operational amplifier can single supply work, that is, do not having
Have in the case of negative supply, input still is able to receive 0V inputs, and can normal work.LM358/324 be it is most common be also price
Minimum single supply op, power consumption 400uA/ can receive substantially per amplifier.
It is seen that, the utility model all provides the situation of the operating voltage of two-wire system sensor in two measuring instruments
Under, the output current of a sensor is divided into two-way while being used for two measuring instruments, and two measuring instruments are collected
Electric current it is identical with the size of current in original sensor.This satisfies some in particular cases with two different measuring instruments
The requirement of the electric current in a sensor is gathered simultaneously, the use number of sensor is also saved, and reduces cost.Device electricity
Line structure is simple, cheap, error very little.
Claims (7)
1. a kind of current collector of two-wire system sensor, it is characterised in that including precision resistance and operational amplifier, the essence
Cipher telegram resistance be connected on for connect the first measuring instrument the first output end and for connect two-wire system sensor input it
Between, for the current signal of two-wire system sensor to be converted into voltage signal；In the voltage signal at the precision resistance two ends
Positive pole is connected with one end of first resistor, negative pole ground connection；The positive of the other end of the first resistor and the operational amplifier
Input is connected, and the other end of the first resistor is also by second resistance and the second output for being connected the second measuring instrument
End is connected；The inverting input of the operational amplifier is directly grounded, and output end is connected with one end of sampling resistor；The sampling
The other end of resistance is connected with the second output end；One end of the sampling resistor is also directly grounded；The resistance of the precision resistance
Much smaller than the first resistor and the resistance of second resistance.
2. the current collector of two-wire system sensor according to claim 1, it is characterised in that the resistance of the sampling resistor
Value is equal with the resistance of the precision resistance.
3. the current collector of two-wire system sensor according to claim 1, it is characterised in that the operational amplifier
Output end is also associated with negative-feedback circuit；The negative-feedback circuit includes triode, the base stage and operation amplifier of the triode
The output end of device is connected, and emitter stage is grounded by 3rd resistor, and colelctor electrode is connected with power end.
4. the current collector of two-wire system sensor according to claim 3, it is characterised in that the operational amplifier
Also it is in series with current-limiting resistance and voltage-regulator diode between output end and ground, the connection end of the current-limiting resistance and voltage-regulator diode is also
It is connected with the base stage of triode.
5. the current collector of two-wire system sensor according to claim 1, it is characterised in that first output end and
Second output end is equipped with a full-bridge rectifier.
6. the current collector of two-wire system sensor according to claim 1, it is characterised in that first output end and
Second output end is equipped with decoupling capacitance.
7. the current collector of two-wire system sensor according to claim 6, it is characterised in that the two of the decoupling capacitance
End is also parallel with TVS pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621206325.6U CN206258503U (en) | 2016-11-09 | 2016-11-09 | A kind of current collector of two-wire system sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621206325.6U CN206258503U (en) | 2016-11-09 | 2016-11-09 | A kind of current collector of two-wire system sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206258503U true CN206258503U (en) | 2017-06-16 |
Family
ID=59024403
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621206325.6U Expired - Fee Related CN206258503U (en) | 2016-11-09 | 2016-11-09 | A kind of current collector of two-wire system sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206258503U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030550A (en) * | 2021-05-25 | 2021-06-25 | 珠海多创科技有限公司 | Non-contact voltage sensor |
-
2016
- 2016-11-09 CN CN201621206325.6U patent/CN206258503U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030550A (en) * | 2021-05-25 | 2021-06-25 | 珠海多创科技有限公司 | Non-contact voltage sensor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102692883B (en) | An analog input circuit for engineering-machinery-dedicated controller | |
| CN202870145U (en) | DC simulation signal acquisition circuit for public transformation terminal | |
| CN106443137A (en) | Electric current collector of two-wire system sensor | |
| CN106768460A (en) | A kind of charging pile pipette tips temperature collection circuit and method | |
| CN205037982U (en) | Utilize constant current source temperature detection circuit of operational amplifier characteristic | |
| CN206258503U (en) | A kind of current collector of two-wire system sensor | |
| CN103412191B (en) | Minitype resistance measurement system | |
| CN204086423U (en) | Super capacitor failure detector | |
| CN204479558U (en) | Intelligent gas acquisition probe | |
| CN201698195U (en) | Expansion circuit of single chip microcomputer IO ports | |
| CN207882338U (en) | A kind of current detection circuit of input circuit | |
| CN206671398U (en) | A kind of photovoltaic off-grid inverter and its isolated form current sampling circuit | |
| CN207798903U (en) | A kind of separator of the adjustable two-wire system current sensor exported in proportion | |
| CN206440799U (en) | A kind of circuit checker | |
| CN203444256U (en) | Signal processing circuit for intelligent product | |
| CN203707767U (en) | Interface protection circuit, control circuit and electrical apparatus of current sensor | |
| CN201654996U (en) | Photoelectric isolation linear transducer | |
| CN201118442Y (en) | A low-voltage power circuit | |
| CN206490664U (en) | Analog quantity modulate circuit | |
| CN102944744A (en) | Low-drift online impedance measurement circuit | |
| CN102314187A (en) | Direct-current voltage proportion output circuit and control method thereof | |
| CN206673849U (en) | The high-performance electric source module that nuclear power station reactor core Nuclear measurement system uses | |
| CN207123777U (en) | The 1mA current source modules for carrying overcurrent protection based on operational amplifier | |
| CN208443888U (en) | One kind being based on STM32 DC Electronic Loads | |
| CN207114615U (en) | A kind of new-energy automobile charging box input voltage detection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170616 Termination date: 20191109 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |