CN110031026B - Capacitance position sensor detection circuit - Google Patents
Capacitance position sensor detection circuit Download PDFInfo
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- CN110031026B CN110031026B CN201910310331.8A CN201910310331A CN110031026B CN 110031026 B CN110031026 B CN 110031026B CN 201910310331 A CN201910310331 A CN 201910310331A CN 110031026 B CN110031026 B CN 110031026B
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- 238000001514 detection method Methods 0.000 title claims abstract description 31
- 239000003990 capacitor Substances 0.000 claims abstract description 14
- 230000007547 defect Effects 0.000 abstract description 2
- 239000002184 metal Substances 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
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Abstract
The invention discloses a capacitor position sensor detection circuit, which comprises a capacitor sensing head, a pulse width modulation circuit, a filter circuit, an electrifying anti-deadlock circuit, a working range adjusting circuit, an output drive and a collision detection circuit, wherein the capacitor sensing head is connected to the pulse width modulation circuit, the pulse width modulation circuit is used for obtaining a pulse width modulation signal related to the position of a measured workpiece, the electrifying anti-deadlock circuit is used for preventing the occurrence of a circuit deadlock state, the filter circuit is used for converting the signal into a voltage signal and removing noise, the working range adjusting circuit is convenient for a user to adjust a detectable capacitance change range, the output drive is used for providing stable voltage output for a subsequent control system, and the collision detection circuit is used for providing a collision output indication. The invention overcomes the defect of the stability of the traditional pulse width modulation circuit and realizes the capacitance position detection with low cost, high stability and high reliability.
Description
Technical Field
The invention relates to the field of detection circuits, in particular to a detection circuit of a capacitive position sensor.
Background
The capacitance position sensor is commonly used for various industrial laser processing applications, the capacitance between the sensing head and a metal processing workpiece changes correspondingly along with the change of the distance between the sensing head and the metal processing workpiece, and the capacitance value is acquired by the capacitance position sensor, so that the laser processing system can automatically adjust the distance between the laser and the workpiece. The most common capacitive position sensor needs a stable high-frequency alternating current power supply, which brings difficulty to implementation of the scheme and acquisition of the detection quantity, and increases the system cost. The existing design is a capacitance position sensor detection circuit, the circuit is based on the pulse width modulation principle, the requirement on a high-frequency alternating-current power supply is avoided, the detection output quantity is voltage output, the requirement on a follow-up control circuit is reduced, the defect of the stability of a traditional pulse width modulation circuit is overcome, and the capacitance position detection with low cost, high stability and high reliability is realized.
Disclosure of Invention
The present invention is directed to a capacitive position sensor detection circuit to solve the above problems.
In order to achieve the purpose, the invention provides the following technical scheme: a capacitance position sensor detection circuit comprises a capacitance sensing head, a pulse width modulation circuit, a filter circuit, a power-on anti-deadlock circuit, a working range adjusting circuit, an output drive and a collision detection circuit, wherein the capacitance sensing head is connected to the pulse width modulation circuit, the pulse width modulation circuit is used for obtaining a pulse width modulation signal related to the position of a measured workpiece, the power-on anti-deadlock circuit is used for preventing the occurrence of circuit deadlock, the filter circuit is used for converting the signal into a voltage signal and removing noise, the working range adjusting circuit is convenient for a user to adjust a detectable capacitance change range, the output drive is used for providing stable voltage output for a subsequent control system to use, the collision detection circuit is used for providing collision output indication, and the pulse width modulation circuit comprises resistors R1, R2, diodes D1 and D2, a capacitor C1, a voltage sensor, a working range adjusting circuit and a collision detection circuit, C30, high stable reference power supply LM4040BIM3-2.5, comparator LM2903AVQPWRQ1, or gate SN74LVC1G32DBV, flip-flop SN74LVC2G74DCT and operational amplifier AD706, said R2 and D2 charge and discharge the sensor head capacitance, said R1 and D1 charge and discharge capacitance C1, C30, said high stable reference power supply LM4040BIM3-2.5, comparator LM2903AVQPWRQ1, or gate SN74LVC1G32DBV, flip-flop SN74LVC2G74DCT are used to obtain the pulse width modulated signal, said operational amplifier AD706 is used to convert the obtained pulse width modulated signal into a voltage signal, comparator LM 3AVQPWRQ1 in said pulse width modulated circuit provides the clock input for D flip-flop LVC2G74DCT through or gate SN 1G32 DBV.
Preferably, the capacitor C45 in the pulse width modulation circuit is used for removing high-frequency glitches on the clock signal.
Preferably, the operating range adjusting circuit comprises a potentiometer for user adjustment of the adjustment bias voltage.
Preferably, the power-on anti-deadlock circuit comprises a transistor Q2, resistors R34, R33 and a capacitor C4.
Compared with the prior art, the invention has the beneficial effects that: the detection circuit of the capacitance position sensor enables the trigger circuit to have consistency through the arranged pulse width modulation circuit, improves the stability of a system, reduces the noise of the system, prevents deadlock caused by misoperation of the system, can realize the function of preventing power-on deadlock by the arranged power-on anti-deadlock circuit, is provided with the working range adjusting circuit, facilitates users to adjust the detectable capacitance change range and enables the capacitance change range to work at the optimal working point.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a pulse width modulation circuit according to the present invention;
FIG. 3 is a power-on anti-deadlock circuit of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-3, the present invention provides a technical solution: a capacitance position sensor detection circuit comprises a capacitance sensing head, a pulse width modulation circuit, a filter circuit, a power-on anti-deadlock circuit, a working range adjusting circuit, an output drive and a collision detection circuit, wherein the capacitance sensing head is connected to the pulse width modulation circuit, the pulse width modulation circuit is used for obtaining a pulse width modulation signal related to the position of a measured workpiece, the power-on anti-deadlock circuit is used for preventing the occurrence of circuit deadlock, the filter circuit is used for converting the signal into a voltage signal and removing noise, the working range adjusting circuit is convenient for a user to adjust a detectable capacitance change range, the output drive is used for providing stable voltage output for a subsequent control system to use, the collision detection circuit is used for providing collision output indication, and the pulse width modulation circuit comprises resistors R1, R2, diodes D1 and D2, a capacitor C1, a voltage sensor, a working range adjusting circuit and a collision detection circuit, C30, high stable reference power supply LM4040BIM3-2.5, comparator LM2903AVQPWRQ1, or gate SN74LVC1G32DBV, flip-flop SN74LVC2G74DCT and operational amplifier AD706, said R2 and D2 charge and discharge the sensor head capacitance, said R1 and D1 charge and discharge capacitance C1, C30, said high stable reference power supply LM4040BIM3-2.5, comparator LM2903AVQPWRQ1, or gate SN74LVC1G32DBV, flip-flop SN74LVC2G74DCT are used to obtain the pulse width modulated signal, said operational amplifier AD706 is used to convert the obtained pulse width modulated signal into a voltage signal, comparator LM 3AVQPWRQ1 in said pulse width modulated circuit provides the clock input for D flip-flop LVC2G74DCT through or gate SN 1G32 DBV.
Further, a capacitor C45 in the pulse width modulation circuit is used for removing high-frequency glitch on the clock signal.
Further, the operating range adjusting circuit comprises a potentiometer for user adjustment of the adjustment bias voltage.
Further, the power-on anti-deadlock circuit comprises a transistor Q2, resistors R34, R33 and a capacitor C4.
The working principle is as follows: the invention relates to a capacitance position sensor detection circuit, which is characterized in that when the detection circuit works, a set pulse width modulation circuit charges and discharges a capacitance sensing head through R2 and D2, charges and discharges capacitors C1 and C30 with high temperature stability through R1 and D1, then obtains a pulse width modulation signal through a high-stability reference power supply LM4040BIM3-2.5, a comparator LM2903AVQPWRQ1, an OR gate SN74LVC1G32DBV and a trigger SN74LVC2G74DCT, and the signal is converted into a voltage signal through a two-stage filter circuit consisting of an operational amplifier AD706 and is filtered. Wherein a user can adjust the bias voltage through a potentiometer in the operating range adjustment circuit to change the measurable capacitance variation range. One path of the filtered signal is clamped and then driven to be output by an operational amplifier AD706, the other path of the filtered signal outputs a collision detection output signal with a selectable high and low level through a comparator LM2903AVQPWRQ1, and meanwhile, different from the traditional pulse width modulation circuit, the output of the comparator LM2903AVQPWRQ1 in the pulse width modulation circuit is not directly used as the input of an RS trigger, but provides clock input for a D trigger SN74LVC2G74DCT through an OR gate SN74LVC1G32DBV, so that a trigger circuit has consistency, the stability of a system is improved, and the noise of the system is reduced. The capacitor C45 can remove high-frequency burrs on a clock signal, deadlock caused by system misoperation is prevented, when the system is powered on, the power-on deadlock prevention circuit enables a clock of the trigger SN74LVC2G74DCT to be in a non-working state by placing the clock at a low level through the AND gate U2, and until the system is powered on, the output of the comparator LM2903AVQPWRQ1 can be used as the clock to cause state conversion of the trigger SN74LVC2G74, so that the function of preventing the DCT from being powered on deadlock is realized.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910310331.8A CN110031026B (en) | 2019-04-17 | 2019-04-17 | Capacitance position sensor detection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910310331.8A CN110031026B (en) | 2019-04-17 | 2019-04-17 | Capacitance position sensor detection circuit |
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| CN110031026A CN110031026A (en) | 2019-07-19 |
| CN110031026B true CN110031026B (en) | 2021-07-02 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02263169A (en) * | 1988-07-21 | 1990-10-25 | General Electric Co <Ge> | Method and apparatus for detecting drop in input voltage into power source device |
| CN101764511A (en) * | 2009-12-25 | 2010-06-30 | 天津市诺尔电气有限公司 | Pulse width modulation signal voltage converting circuit |
| CN102825365A (en) * | 2012-09-12 | 2012-12-19 | 湘潭大学 | Automatic tracking system and method of welding line based on capacitive transducer |
| CN103090892A (en) * | 2011-10-31 | 2013-05-08 | 宋宏宇 | Capacitance type sensor detecting method and capacitance type sensor system |
| CN103513283A (en) * | 2012-06-28 | 2014-01-15 | 博泽哈尔施塔特汽车零件两合公司 | Capacitive sensor for an anti-collision apparatus |
| CN107478859A (en) * | 2017-06-27 | 2017-12-15 | 浙江大学 | A kind of pulsewidth is double to add square type acceleration sensor circuit |
-
2019
- 2019-04-17 CN CN201910310331.8A patent/CN110031026B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02263169A (en) * | 1988-07-21 | 1990-10-25 | General Electric Co <Ge> | Method and apparatus for detecting drop in input voltage into power source device |
| CN101764511A (en) * | 2009-12-25 | 2010-06-30 | 天津市诺尔电气有限公司 | Pulse width modulation signal voltage converting circuit |
| CN103090892A (en) * | 2011-10-31 | 2013-05-08 | 宋宏宇 | Capacitance type sensor detecting method and capacitance type sensor system |
| CN103513283A (en) * | 2012-06-28 | 2014-01-15 | 博泽哈尔施塔特汽车零件两合公司 | Capacitive sensor for an anti-collision apparatus |
| CN102825365A (en) * | 2012-09-12 | 2012-12-19 | 湘潭大学 | Automatic tracking system and method of welding line based on capacitive transducer |
| CN107478859A (en) * | 2017-06-27 | 2017-12-15 | 浙江大学 | A kind of pulsewidth is double to add square type acceleration sensor circuit |
Non-Patent Citations (1)
| Title |
|---|
| 电容传感器激光焦点检测误差分析;刘强等;《工业仪表与自动化装置》;19980331(第3期);第3-6、39页 * |
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| CN110031026A (en) | 2019-07-19 |
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Effective date of registration: 20240819 Address after: 100081 No. 5 South Main Street, Haidian District, Beijing, Zhongguancun Patentee after: BEIJING INSTITUTE OF TECHNOLOGY Country or region after: China Patentee after: Anfeiteng (Changzhou) Photoelectric Technology Co.,Ltd. Address before: Room 403, 4th floor, block a, Zhongchuang service center, No.1 Xihu Road, Wujin national high tech Industrial Development Zone, Changzhou City, Jiangsu Province, 213000 Patentee before: Anfeiteng (Changzhou) Photoelectric Technology Co.,Ltd. Country or region before: China |