CN213581799U - Differential measurement circuit based on plastic optical fiber isolation - Google Patents
Differential measurement circuit based on plastic optical fiber isolation Download PDFInfo
- Publication number
- CN213581799U CN213581799U CN202022791017.7U CN202022791017U CN213581799U CN 213581799 U CN213581799 U CN 213581799U CN 202022791017 U CN202022791017 U CN 202022791017U CN 213581799 U CN213581799 U CN 213581799U
- Authority
- CN
- China
- Prior art keywords
- circuit
- optical fiber
- microprocessor
- resistor
- operational amplifier
- 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.)
- Active
Links
Images
Landscapes
- Electronic Switches (AREA)
Abstract
The utility model discloses a differential measurement circuit based on plastic optical fiber isolation, including sampling circuit, power supply circuit and receiving circuit, sampling circuit include differential circuit, ADC module, first microprocessor, the output of differential circuit pass through the ADC module and connect the input of first microprocessor; the receiving circuit comprises a second microprocessor, a DAC module, a low-pass filter circuit and a unipolar-bipolar conversion circuit. The utility model discloses a set up the preceding stage and adopt differential circuit to convert the measured voltage, export with the USART interface after first microprocessor's ADC sampling, the change of control fiber sender output light pulse, after second microprocessor received the data signal of plastics fiber receiver output, convert analog signal output into after interpolation processing, rethread low-pass filter circuit and unipolar-bipolar converting circuit output, provide a feasibility for the signal detection of low-cost high suspension potential.
Description
Technical Field
The utility model relates to a difference measurement technical field especially relates to a difference measurement circuit based on plastics optic fibre is kept apart.
Background
At present, a differential measurement circuit has the characteristics of simple structure, convenience in use, capability of measuring direct current and ultralow frequency signals, low power consumption and the like, so that the differential measurement circuit is increasingly widely applied to various fields such as household electrical appliance control, industrial equipment, series battery pack detection and the like. However, the voltage resistance of the differential arm is low, the voltage of a commonly used measuring circuit is low, increasing the voltage resistance value of elements of the differential arm can cause increase of cost and volume, meanwhile, noise introduced by high impedance enables the signal-to-noise ratio of measurement to be obviously reduced, and particularly when a small voltage signal is measured at a high common mode potential, the precision and the voltage adaptation range of the measuring method are poor, so that how to improve detection is achieved, and meanwhile, the problem that cost can be reduced is urgently needed to be solved.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a differential measurement circuit based on plastics optic fibre is kept apart can realize the signal detection of low-cost high suspension potential.
The utility model adopts the technical proposal that:
a differential measurement circuit based on plastic optical fiber isolation is characterized in that a transmission medium is a plastic optical fiber and comprises a sampling circuit, a power supply circuit and a receiving circuit, wherein the sampling circuit comprises a differential circuit, an ADC module and a first microprocessor, and the output end of the differential circuit is connected with the input end of the first microprocessor through the ADC module; the receiving circuit comprises a second microprocessor, a DAC module, a low-pass filter circuit and a unipolar-bipolar conversion circuit, and the power supply circuit is used for supplying power to the adoption circuit and the receiving circuit respectively.
The differential circuit comprises an operational amplifier U1, resistors R1, R2, R3, R4, R5, a capacitor C1, diodes D1, D2, D3 and D4, wherein the resistor R1 is serially connected between the negative input of the operational amplifier and the negative electrode of the optical fiber input, the resistor R1 is serially connected between the positive input of the operational amplifier and the positive electrode of the optical fiber input, the resistor R3 is parallelly connected with the negative input of the operational amplifier and the output end of the operational amplifier U1, one end of the resistor R4 is connected with the positive input of the operational amplifier U1, and the other end of the resistor R4 is connected with a power supply; diodes D1 and D2 are respectively connected in parallel between the anode input and the cathode input of the operational amplifier U1, one end of the resistor R5 is connected with the output end of the operational amplifier U1, the other end of the resistor R5 is connected with the input end of the first microprocessor, the input end of the first microprocessor is grounded through a capacitor C1 and is simultaneously connected with the anode of the diode D3 and the cathode of the diode D4, the cathode of the diode D3 is connected with a power supply, and the anode of the diode D4 is connected with the ground wire.
The power supply circuit comprises a step-down voltage regulator LDO for reducing the voltage of a battery to +3.3V and a secondary step-down circuit for converting the +3.3V into +1.65V, wherein the secondary step-down circuit comprises a power supply IC, the power supply IC adopts AZ432 and a peripheral circuit, and the peripheral circuit comprises resistors R6, R7, R8 and a capacitor C2.
The bipolar conversion circuit comprises a follower U8 and is used for matching impedance characteristics of front and rear stages, and further comprises a reverse amplification circuit consisting of R10, R11 and U9, a zero correction circuit consisting of R12, R13, R14 and C10, and a post-filter circuit consisting of R15 and C9 and used for filtering operational amplifier noise, wherein an output end of the follower U8 is connected with one end of the R15 through resistors R10 and R11 in sequence, the other end of the R15 is an output end, the capacitor C9 is connected between the output end and the ground wire in series, a negative input end of the amplifier U9 is connected with a connection point of the resistor R10 and the resistor R11, a positive input end of the amplifier U9 is connected with an adjustable end of the resistor R13, the resistors R12, R13 and R14 are connected between a power output end and the ground wire in series, and the capacitor C10 is connected between a positive input end of the amplifier U9 and the ground wire in series.
The handler U1 is tth 2501.
The LDO adopts 1117.
The length of the optical fiber is not more than 10 meters.
The power supply circuit also comprises a negative voltage generating circuit used for supplying power to the bipolar conversion circuit, and the negative voltage generating circuit is composed of a charge pump 7660 and a peripheral circuit.
The utility model discloses a set up the preceding stage and adopt differential circuit to carry out the conversion to being measured voltage, export with the USART interface after first microprocessor's ADC sampling, control optical fiber transmitter output light pulse's change, through plastics optical fiber transmission to receiving terminal, after second microprocessor received the data signal of plastics optical fiber receiver output, through DAC conversion after interpolation processing for analog signal output, the rethread low pass filter circuit and unipolar-bipolar converting circuit output. The output signal has the same trend with the preceding stage test signal, and has a certain proportion corresponding relation according to the circuit and the program design, thereby providing feasibility for the signal detection of low cost and high suspension potential.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic circuit diagram of a differential circuit according to the present invention;
fig. 2 is a power circuit diagram of the present invention for supplying power to the preceding stage differential circuit, the first microprocessor, and the optical fiber transmitter;
FIG. 3 is a schematic diagram of a unipolar-bipolar switching circuit according to the present invention;
fig. 4 is a schematic view of the connection relationship of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without any creative effort belong to the protection scope of the present invention.
As shown in fig. 1, 2 and 3, the present invention includes a sampling circuit, a power circuit and a receiving circuit, wherein the sampling circuit includes a differential circuit, an ADC module and a first microprocessor, and an output terminal of the differential circuit is connected to an input terminal of the first microprocessor through the ADC module; the receiving circuit comprises a second microprocessor, a DAC module, a low-pass filter circuit and a unipolar-bipolar conversion circuit, and the power supply circuit is used for supplying power to the adoption circuit and the receiving circuit respectively.
Fig. 1 is the schematic diagram of the preceding stage differential circuit in the embodiment of the present invention. The differential circuit comprises an operational amplifier U1, resistors R1, R2, R3, R4, R5, a capacitor C1, diodes D1, D2, D3 and D4, wherein the resistor R1 is serially connected between the negative input of the operational amplifier and the negative electrode of the optical fiber input, the resistor R1 is serially connected between the positive input of the operational amplifier and the positive electrode of the optical fiber input, the resistor R3 is parallelly connected with the negative input of the operational amplifier and the output end of the operational amplifier U1, one end of the resistor R4 is connected with the positive input of the operational amplifier U1, and the other end of the resistor R4 is connected with a power supply; diodes D1 and D2 are respectively connected in parallel between the positive input and the negative input of the operational amplifier U1, one end of the resistor R5 is connected with the output end of the operational amplifier U1, the other end of the resistor R5 is connected with the input end of the first microprocessor, the input end of the first microprocessor is grounded through a capacitor C1 and is simultaneously connected with the positive electrode of the diode D3 and the negative electrode of the diode D4, the negative electrode of the diode D3 is connected with +3.3V, and the positive electrode of the diode D4 is connected with GND. Wherein R1/R3= R2/R4, attenuation coefficient K = R1/R3, D1 and D2 play the role of protecting the operational amplifier, and the other end of R4 is connected with +1.65V to provide a direct current offset for the whole differential circuit, so that the bipolar sampling signal is converted into a unipolar signal which can be received by the ADC. R5C1 plays a role in filtering high-frequency noise, and D3 and D4 protect the ADC from exceeding the tolerance voltage value.
The power supply comprises a step-down voltage regulator LDO for reducing the voltage of a battery to +3.3V and a secondary step-down circuit for converting the +3.3V into +1.65V, wherein the secondary step-down circuit comprises a power supply IC, the power supply IC adopts AZ432 and a peripheral circuit, and the peripheral circuit comprises resistors R6, R7, R8 and a capacitor C2. Fig. 2 shows an embodiment of the present invention, in which the power supply circuit of the transmitting part converts +3.3V into +1.65V using AZ432, so as to provide dc bias for the differential circuit. The LDO is used to reduce the battery voltage to +3.3V to power the microprocessor 1, the plastic fiber transmitter. The battery adopts 3 AA batteries, and the voltage is converted into 3.3V required by the microprocessor through the LDO. The power supply circuit also comprises a negative voltage generating circuit for supplying power to the bipolar conversion circuit. The negative voltage generating circuit is powered by a negative power supply of the bipolar conversion circuit realized by the charge pump 7660. Since it is an existing product, detailed structure and connection relation thereof are not described herein, and the charge pump 7660 has the advantages of low power consumption, low switching harmonic frequency, and sine characteristic, and is convenient for filtering.
FIG. 3 is a schematic diagram of a unipolar-bipolar switching circuit according to an embodiment of the present invention; the bipolar conversion circuit comprises a follower U8 and is used for matching impedance characteristics of front and rear stages, and further comprises a reverse amplification circuit consisting of R10, R11 and U9, a zero correction circuit consisting of R12, R13, R14 and C10, and a post-filter circuit consisting of R15 and C9 and used for filtering operational amplifier noise, wherein an output end of the follower U8 is connected with one end of the R15 through resistors R10 and R11 in sequence, the other end of the R15 is an output end, the capacitor C9 is connected between the output end and the ground wire in series, a negative input end of the amplifier U9 is connected with a connection point of the resistor R10 and the resistor R11, a positive input end of the amplifier U9 is connected with an adjustable end of the resistor R13, the resistors R12, R13 and R14 are connected between a power output end and the ground wire in series, and the capacitor C10 is connected between a positive input end of the amplifier U9 and the ground wire in series. The unipolar-bipolar conversion circuit outputs voltage signals which have the same trend with the preceding stage differential circuit and are compounded in a certain proportion corresponding relationship.
The plastic optical fiber is used as a transmission medium, the differential circuit is used as a preceding stage sensing part at the sampling end, and the signal quantization acquisition is carried out by matching with an ADC (analog to digital converter) arranged in the microprocessor 1. The receiving end uses the built-in DAC of the microprocessor 2 to match with the low-pass filter circuit and the unipolar-bipolar conversion circuit to output corresponding signals, so as to meet the signal detection function under the high common mode voltage of different suspension potentials.
The operational amplifier U1 is a high-speed rail-to-rail operational amplifier for TPH2501, and can meet the output voltage range and bandwidth characteristics when low power supply voltage supplies power. The LDO adopts 1117, and is simple and reliable. The length of the optical fiber is not more than 10 meters, and the error rate of output transmission exceeding 10 meters can be obviously increased.
The differential circuit is used as a sensing part for detecting a preceding stage signal, and the output of the differential circuit is sampled by an ADC module built in the microprocessor 1. The preceding stage sampling and sending part is powered by a battery, and meets the safe measurement condition of the suspension potential.
The utility model discloses data after the sampling, after 1 filtering process of first microprocessor, will convert the data of digital quantity into through the USART mouth and send. The USART interface controls the plastic optical fiber transmitter, converts the LVTTL signal into the light pulse which changes discontinuously, and the plastic optical fiber is transmitted to the receiving end as a result. And after the second microprocessor 2 at the receiving end receives the data of the LVTTL level converted by the plastic optical fiber receiver through the USART port, the data is processed in modes of interpolation and the like, and then the data is output through a built-in DAC module. After high-frequency components of the signals output by the DAC are filtered by a low-pass filter, the signals are converted into signals with the same trend, which have the same positive and negative polarities as the input differential signals and certain attenuation coefficients, through a unipolar-bipolar conversion circuit and then are output.
The utility model discloses in the implementation, the built-in ADC module of first microprocessor 1 is to the signal sampling back, according to the pre-storage when dispatching from the factory in the inside zero offset calibration register of microprocessor data, rectify ADC sampling data, reject the unusual value of individuality through suitable filter algorithm again, according to the data after the processing algorithm that presets will be updated, send to the plastic fiber transmitter through the USART interface, change LVTTL signal into intermittent change's optical pulse, send away through plastic fiber. Similarly, between the second microprocessor 2 and the plastic optical fiber receiver, after the plastic optical fiber receiver receives the light pulse with the discontinuous change from the optical fiber, the light pulse is converted into a signal with LVTTL level, the signal is input into a USART interface of the second microprocessor 2, and after serial-parallel conversion, the current voltage sampling signal of the corresponding sending part is read out. Since the algorithms designed as described above are conventional known methods and are not an improvement of the present invention, there is no case where the algorithms do not belong to the protection subject.
The embodiment of the utility model provides an in according to when dispatching from the factory prestore in microprocessor inside zero offset calibration register data, rectify received data, correct through the data polarity who cooperates back level unipolar-bipolar converting circuit again, export by the DAC module behind the inside SINC software filter of second microprocessor 2, DAC output signal gets into RC low pass filter circuit to the influence of quantization error when filtering analog-to-digital conversion.
Fig. 4 is a connection diagram of the transmitting part and the receiving part. The two parts are connected by a single plastic optical fiber, and the maximum length of the optical fiber is not more than 10 meters.
The utility model discloses based on plastic optical fiber is as transmission medium, the sampling end uses differential circuit as preceding stage sensing part, cooperates the built-in ADC of first microprocessor 1 to carry out the signal quantization and gathers. The receiving end uses the built-in DAC of the second microprocessor 2 to match with the low-pass filter circuit and the unipolar-bipolar conversion circuit to output corresponding signals, so that the signal detection function under the high common mode voltage of different suspension potentials is realized.
In the description of the present invention, it should be noted that, for the orientation words, if there are terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation and positional relationship indicated are based on the orientation or positional relationship shown in the drawings, and only for the convenience of describing the present invention and simplifying the description, it is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and not be construed as limiting the specific scope of the present invention.
It is noted that the terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles thereof. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the specific embodiments described herein, and may include more effective embodiments without departing from the scope of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (8)
1. The utility model provides a difference measurement circuit based on plastic fiber keeps apart, transmission medium is plastic fiber, its characterized in that: the sampling circuit comprises a differential circuit, an ADC module and a first microprocessor, wherein the output end of the differential circuit is connected with the input end of the first microprocessor through the ADC module; the receiving circuit comprises a second microprocessor, a DAC module, a low-pass filter circuit and a unipolar-bipolar conversion circuit, and the power supply circuit is used for supplying power to the adoption circuit and the receiving circuit respectively.
2. The differential measurement circuit based on plastic optical fiber isolation according to claim 1, wherein: the differential circuit comprises an operational amplifier U1, resistors R1, R2, R3, R4, R5, a capacitor C1, diodes D1, D2, D3 and D4, wherein the resistor R1 is serially connected between the negative input of the operational amplifier and the negative electrode of the optical fiber input, the resistor R1 is serially connected between the positive input of the operational amplifier and the positive electrode of the optical fiber input, the resistor R3 is parallelly connected with the negative input of the operational amplifier and the output end of the operational amplifier U1, one end of the resistor R4 is connected with the positive input of the operational amplifier U1, and the other end of the resistor R4 is connected with a power supply; diodes D1 and D2 are respectively connected in parallel between the anode input and the cathode input of the operational amplifier U1, one end of the resistor R5 is connected with the output end of the operational amplifier U1, the other end of the resistor R5 is connected with the input end of the first microprocessor, the input end of the first microprocessor is grounded through a capacitor C1 and is simultaneously connected with the anode of the diode D3 and the cathode of the diode D4, the cathode of the diode D3 is connected with a power supply, and the anode of the diode D4 is connected with the ground wire.
3. The differential measurement circuit based on plastic optical fiber isolation according to claim 1, wherein: the power supply circuit comprises a step-down voltage regulator LDO for reducing the voltage of a battery to +3.3V and a secondary step-down circuit for converting the +3.3V into +1.65V, wherein the secondary step-down circuit comprises a power supply IC, the power supply IC adopts AZ432 and a peripheral circuit, and the peripheral circuit comprises resistors R6, R7, R8 and a capacitor C2.
4. The differential measurement circuit based on plastic optical fiber isolation according to claim 1, wherein: the bipolar conversion circuit comprises a follower U8 and is used for matching impedance characteristics of front and rear stages, and further comprises a reverse amplification circuit consisting of R10, R11 and U9, a zero correction circuit consisting of R12, R13, R14 and C10, and a post-filter circuit consisting of R15 and C9 and used for filtering operational amplifier noise, wherein an output end of the follower U8 is connected with one end of the R15 through resistors R10 and R11 in sequence, the other end of the R15 is an output end, the capacitor C9 is connected between the output end and the ground wire in series, a negative input end of the amplifier U9 is connected with a connection point of the resistor R10 and the resistor R11, a positive input end of the amplifier U9 is connected with an adjustable end of the resistor R13, the resistors R12, R13 and R14 are connected between a power output end and the ground wire in series, and the capacitor C10 is connected between a positive input end of the amplifier U9 and the ground wire in series.
5. The differential measurement circuit based on plastic optical fiber isolation as claimed in claim 2, wherein: the handler U1 is tth 2501.
6. The differential measurement circuit based on plastic optical fiber isolation according to claim 3, wherein: the LDO adopts 1117.
7. The differential measurement circuit based on plastic optical fiber isolation according to claim 1, wherein: the length of the optical fiber is not more than 10 meters.
8. A differential measurement circuit based on plastic optical fiber isolation according to any of claims 1-7, wherein: the power supply circuit also comprises a negative voltage generating circuit used for supplying power to the bipolar conversion circuit, and the negative voltage generating circuit is composed of a charge pump 7660 and a peripheral circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022791017.7U CN213581799U (en) | 2020-11-27 | 2020-11-27 | Differential measurement circuit based on plastic optical fiber isolation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022791017.7U CN213581799U (en) | 2020-11-27 | 2020-11-27 | Differential measurement circuit based on plastic optical fiber isolation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213581799U true CN213581799U (en) | 2021-06-29 |
Family
ID=76545053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022791017.7U Active CN213581799U (en) | 2020-11-27 | 2020-11-27 | Differential measurement circuit based on plastic optical fiber isolation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213581799U (en) |
-
2020
- 2020-11-27 CN CN202022791017.7U patent/CN213581799U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN204203687U (en) | A kind of analogue quantity output circuit | |
| CN203705533U (en) | Current detection circuit of Hall current sensor of electric automobile | |
| CN112147401A (en) | Current detection circuit based on Hall current sensor | |
| CN103414474A (en) | High-precision small-signal difference analog-digital converter | |
| CN107132167A (en) | High precision two line system industrial dust detection means | |
| CN213581799U (en) | Differential measurement circuit based on plastic optical fiber isolation | |
| CN111721995A (en) | Isolation sampling circuit of direct current voltage signal | |
| CN207816478U (en) | Temperature measuring circuit | |
| CN112698603A (en) | Measuring circuit | |
| CN203812008U (en) | Analog signal collector | |
| CN206281870U (en) | Acceleration transducer | |
| CN213021626U (en) | Universal measurement conversion circuit of photoelectric encoder based on DSP | |
| CN211856874U (en) | Residual current transformer measurement and abnormity detection circuit based on metering unit | |
| CN115219781A (en) | Positive and negative voltage sampling circuit and sampling system with same | |
| CN211183539U (en) | Electricity safety public management system for university dormitory | |
| CN214335500U (en) | Measuring circuit | |
| CN107966207A (en) | Load ratio bridging switch vibration signal acquisition device and analysis system | |
| CN209803233U (en) | Signal acquisition circuit compatible with current and voltage input | |
| CN207991999U (en) | High precision two line system industrial dust detection device | |
| CN201373881Y (en) | Input signal circuit of signal transmitting meter | |
| CN207036332U (en) | A kind of signal processing system of high pressure flow auto-controlling apparatus | |
| CN207231660U (en) | Temperature measuring circuit | |
| CN210864453U (en) | Intelligent frequency transmitter | |
| CN213632448U (en) | Compatible Pt temperature sensor sampling circuit | |
| CN217332616U (en) | High-precision current detection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |