CN1102253A - Linear position sensor with equalizing means - Google Patents
Linear position sensor with equalizing means Download PDFInfo
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- CN1102253A CN1102253A CN 93118882 CN93118882A CN1102253A CN 1102253 A CN1102253 A CN 1102253A CN 93118882 CN93118882 CN 93118882 CN 93118882 A CN93118882 A CN 93118882A CN 1102253 A CN1102253 A CN 1102253A
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- signal
- operational amplifier
- hydraulic cylinder
- frequency
- piston
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
- F15B15/2869—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using electromagnetic radiation, e.g. radar or microwaves
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- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The present invention relates to a linear position sensor with equilizing device. Said device can detect the linear extension length, speed and acceleration of hydraulic cylinder. Said hydraulic cylinder forms a variable-length coaxial resonant cavity. Under the condition of control of a controller, a radio emission portion and a radio receiving portion are used for determining resonance frequency of said cavity. Said receiving portion includes a comparator circuit used for raising sensitivity of said sensor and removing false detection of resonance frequency of hydraulic cylinder, and the linear extension length of the hydraulic cylinder is determined as the function of resonance frequency.
Description
The present invention generally speaking relates to and a kind ofly is determined in the cylinder body or the device of cylinder barrel inner carrier and piston rod position, more particularly relates to a kind of device that adopts radio frequency (RF) signal measuring piston position.
In the field of hydraulic cylinder, people have proposed all systems of surveying and show the displacement of hydraulic cylinder parts or utilize the displacement of hydraulic cylinder parts to control with electric approach.Traditional sensor has many important disadvantages, in part because traditional sensor installation difficulty is big and the residing environmental baseline of sensor is relatively harsher.The used sensor of hydraulic system is because relatively poor easier the suffering damage of working environment in weight equipment industry.Hydraulic cylinder all be arranged on usually be protected fewer local and be subjected to such as high g power, bigger difference variation, dust, water, the influence of chip etc., these adverse environments probably cause the fault of electric and mechanical aspects.
For providing a kind of approach of suitable sensor, heavy equipment manufacturing industry is to use radiofrequency signal.Authorized on April 12nd, 1988 in people's such as Bitar the United States Patent (USP) 4,737,705 and disclosed a kind of like this system.People's such as Bitar system sends into a coaxial resonator of being made up of hydraulic cylinder to a slope radiofrequency signal.When the resonance frequency of hydraulic cylinder sends, the received signal of receiving antenna reaches peak value, and the linear extension length of this resonance frequency and hydraulic cylinder has corresponding relation one by one, therefore, by measuring the resonance frequency of hydraulic cylinder, just can measure the development length of hydraulic cylinder.The peak value of the signal that is received is by being detected with a threshold.Then, resonance frequency is to determine with the difference of adjusting between threshold value and the true peak by the frequency that records of revising the signal of being launched.This adjusting has brought error to the mensuration of position because transmit and actual resonance frequency between difference be resonance frequency along with hydraulic cylinder, the difference of the degree of accuracy of threshold value and hydraulic cylinder size and dimension and different.
The frequency of the signal that is sent is to measure by some round-robin cycle of measuring the signal that is sent.When reaching threshold value, people's such as Bitar system just makes this frequency keep constant.This has also increased the possibility that produces error, because the development length of hydraulic cylinder might change, thereby has also changed the resonance frequency in chamber.In addition, error also may be caused by the noise of system and the frequency drift of signal transmitter.
And the fabrication tolerance of the electric component of sensor also may cause error.For example, received signal and threshold value all have only tens millivolts usually, and the variation of the fabrication tolerance of electric component may cause the difference or the error of hundreds of millivolt, the false triggering the when noise that these variations are caused and the noise in other sources all may cause resonance frequency to detect.
Purpose of the present invention is intended to overcome above-mentioned one or more existing problem.
One aspect of the present invention provides the device of the linear position of piston that detection moves and piston rod in the cylinder body of hydraulic cylinder or cylinder barrel.This device sends an electromagnetic signal and detects this electromagnetic wave signal in the hydraulic cylinder in hydraulic cylinder, then this electromagnetic wave signal and a predetermined constant basis are compared.This device with the development length of hydraulic cylinder as the function of frequency signal and measure the development length of hydraulic cylinder.
Fig. 1 is the block scheme of a RF linear position transducer according to an embodiment of the invention, and the sensor among the figure comprises three parts: a radiating portion, a receiving unit and a control section;
Fig. 2 is the more detailed functional-block diagram of RF linear position transducer embodiment illustrated in fig. 1;
Fig. 3 is the electrical schematics of Fig. 2 receiving unit.
Now see also Fig. 1.Among the figure, device 102 of the present invention can be measured the position of the piston 104 and the piston rod 106 thereof of common hydraulic cylinder 108.Device 102 of the present invention also can be used for measuring the speed and the acceleration of piston 104 and piston rod 106 thereof.The linear extension length of hydraulic cylinder can be measured by using radiofrequency signal with multiple device and method.
The total length of piston rod 106 is L
T, it can move in the cylinder body of hydraulic cylinder 108 or cylinder barrel 110.Piston rod 106 and cylinder body 110 are formed a variable coaxial cavity 112.
The length L of this coaxial cavity 112
C, equal total length L
T Deduct piston rod 106 and stretch the length L of part outside
EAdd the thickness of cylinder barrel 110 end walls.Therefore, measured the length L of cavity 112
CAfter, just can directly draw the length L of bar that extends in the outside
E, as the indicated value of piston rod 106 development lengths.Device 102 detection pistons 104 of the present invention and piston rod 106 are directly to show detected position or be used for control example such as the system of the position of building industry Construction traffic worktable with respect to the purpose of the position of cylinder body 110.
The signal emission part 114 of this device produces an electromagnetic signal and this electromagnetic signal is sent in the coaxial resonator cavity 112.The frequency of this electromagnetic signal can change between a predetermined minimum and maximal value.For example can between 1.6 kilo-mega cycles per seconds, change at 50 megahertzes.Signal emission part 114 comprises a coupling unit 122, this coupling unit 122 can comprise an antenna, one electric field or magnet field probe or directly be connected with piston rod 106, preferably this coupling unit 122 is loop antennas, loop antenna 122 can enter cavity from cylinder barrel head or cylinder barrel wall.In one embodiment of the invention, tours antenna 122 enters cavity 112 and is electrically connected with the inside surface of side wall or the cylinder barrel head of cylinder body or cylinder barrel 110.In another embodiment, this tours antenna 122 enters cavity 112 and is electrically connected with piston rod 106.
Receiving unit 116 of the present invention is from the coaxial cavity 112 inner electromagnetic wave signals that detect.Receiving unit 116 detect the signal that received and the slope between the threshold value intersect or cut condition mutually and have in response to correspondence described slope condition electromagnetic signal frequency and produce a frequency signal.Described slope intersect or mutually the condition of cutting be meant intersecting or cut mutually between detected voltage-frequency curve and the threshold voltage.
In one embodiment of the invention, receiving unit 116 detects the positive slope condition of cutting mutually and afterwards correspondingly produces a first frequency signal, and then detects a negative slope and cut condition mutually, correspondingly produces a second frequency signal simultaneously.The high frequency side that the lower frequency side that intersect on positive slope or the condition of cutting occurs in resonance mutually, negative slope intersect or the condition of cutting occurs in resonance mutually.
In yet another embodiment, the slope that receiving unit 116 detects electromagnetic wave signal is intersected or is cut condition mutually, follows the tracks of the frequency that condition is intersected or cuts mutually on the slope then, and correspondingly produces a first frequency signal.Described receiving unit 116 comprises that one receives coupling unit 120.This receives preferably as mentioned above a tours antenna of coupling unit 120.
Described coaxial resonator 112 has the response characteristic that is similar to short coaxial transmission line.Hydraulic cylinder 108 comprises that a conducting ring (not drawing among the figure) is to provide being electrically connected between cylinder body 110 and the piston rod 106.
When cavity 112 during by the radio signal excitation, near resonance frequency, it has high insertion loss, more particularly, if the length L of cavity 112
CBe the integral multiple that is sent to the half-wavelength of the signal in the coaxial cavity 112, the part radio frequency line just is coupled with cavity 112, inspires a transverse electric and magnetic field (TEM), and so-called transverse electric and magnetic field is exactly the stack along two ripples of coaxial cavity 112 transmission.This time dependent electromagnetic field that exists in the chamber 112 makes and receives the signal that coupling unit 120 detects a same frequency.Each integral multiple all is a harmonic wave or resonance frequency.
The resonance frequency of desirable coaxial cavity is provided by following formula:
f
Res=(n)/2 | (C)/((E
r)
1/2) * 1/ (L
c) | formula 1 (n=1,2,3 ...)
In the formula, C=3 * 10
10Cm/s, f
ResBe excitation frequency, E
rIt is the relative dielectric constant of chamber inner fluid.First harmonic is corresponding to n=1, and second harmonic is corresponding to n=2, or the like.
The resonance frequency that the resonance frequency of coaxial cavity 112 and above-mentioned desirable equation provide is incomplete same, and is because deviation can take place the geometric configuration of cavity 112, also relevant with the effect of the coupled structure of reality in addition.But, at the actual resonance frequency and the hydraulic cylinder body L of cavity 112
CLength between have one-to-one relationship, the deviation of it and desirable cavity can be solved by each class hydraulic cylinder is calibrated.
In one embodiment of the invention, position finding part 118 is measured the position of piston and piston rod 104 and 106 by the resonance frequency of measuring coaxial resonator 112.The resonance frequency of coaxial resonator 112 is functions of frequency signal.In preferred embodiment, by measuring concrete frequency measuring period.
For example, in one embodiment, receiving unit 116 is followed the tracks of the frequency that positive slopes intersects or cuts mutually.This frequency is adjusted then so that the difference between threshold value and the actual resonance is taken into account.Adjust the resonance frequency that later value is used as coaxial cavity 112 then.
In another embodiment, the cycle of resonance frequency is measured as the function of first, second frequency signal (slope that corresponds respectively to positive and negative is cut or crossing condition mutually), and its general expression formula is:
P
Res=f(P
1, P
2) equation 2
In the formula, P
1, P
2Be corresponding to first, second frequency signal f
1, f
2Record the cycle.In one embodiment, the cycle of resonance frequency is provided by following formula:
P
Res=(P
1+ P
2)/2 equation 2A
In another embodiment, the cycle of resonance frequency is provided by following formula:
Pu is based on the parameter of cylinder barrel size and position in the formula
Now see also Fig. 2.The signal transmission unit that there is shown the preferred embodiment according to the present invention divides 114 and the block diagram of signal receive section 116.The signal transmission unit branch comprises first and second voltage-controlled oscillators (VCO) 202,204,206 couples first and second VCO202 of one balanced mixer, 204 output mixes, one low-pass filter 208 is connected to emission coupling unit 122 with the output of mixer 206, necessary, can add the output of a radio frequency amplifier (not drawing among the figure) with amplification low pass device 208.
Receiving unit 116 comprises a radio frequency amplification apparatus 212, in order to amplify the signal that closes coupling unit 120 from reception.This multiplying arrangement comprises the device of the electromagnetic signal that equilibrium is received, and this equalizing device can compensate the variation with respect to the insertion loss of hydraulic cylinder 108 frequencies and other radio circuits.This equalizing device can make a received signal and a constant threshold value compare.
In preferred embodiment, the gain of equalizing device 116 is substantially equal near the inverse of the gain (loss) of the hydraulic cylinder 100 the resonance in by the frequency range that minimum and maximum value limited.The minimum value that the gain of equalizing device 116 approaches to be scheduled to during near maximal value in the frequency of electromagnetic signal.
The output frequency of 210 pairs of low-pass filters 208 of one prescaler is calibrated.In preferred embodiment, prescaler 210 divided by 256, correspondingly produces a frequency signal with the output frequency of low-pass filter 208.
The output signal of installing 214 received RF amplifier/balanced devices 212 correspondingly produces a signal that shows the electromagnetic wave signal amplitude.
The output of multiplying arrangement 216 amplification detection devices 214, and with a predetermined value or threshold value V
THCompare.
The output signal of one anti-phase/noninverting multiplying arrangement 218 pair amplifiers/balanced device 210 is amplified and anti-phase output and a noninverting output is provided.
Integration is carried out in the output of 220 pairs of anti-phase/non-inverting amplifiers 218 of one integrating gear.
One switchgear 224 carries out switch transition between the anti-phase and noninverting output of amplifier 216.
One lock detection device 226 sends this control device of signalisation for when the occurrence frequency lock condition control device 118.
Described control device 118 comprises a sensor controller 228 and a counting assembly 230.In preferred embodiment, sensor controller 228 usefulness microprocessors are made.A kind of suitable microprocessor can be buied from ILLinois state Roselle Mo Tuoluola company, and the article number of this microcomputer is MC68HC11.In preferred embodiment, little processing can receive the information from calculation element 230, measures the position of plug and stopper rod 104,106 while still alive, speed and acceleration, and data are sent to external user.
For example, in the automatic station-keeping system that the building industry Construction traffic is used, the position of piston, piston rod 104,106 and/or speed and/or acceleration be used for controlling Construction traffic connecting rod the position and move.
Typically use other, an independent control system.
In preferred embodiment, the output pulse of 230 pairs of prescalers 210 of counting assembly is counted, and in a preferred embodiment, described counting assembly 230 comprises a breech lock or trigger 232, one first counter, 234, one second counters 236 and an AND 238 are as shown in the figure.
Now see also Fig. 3.There is shown the circuit diagram of receiving unit 116.Control device 118 is by the operation of control line C1 and C2 control receiving unit 116.C1 is that a reset line C2 then is provided with the detection that positive and negative slope is intersected or cut mutually, and the signal of C1 is a reset signal, and it resets device 102 and measures in location/velocity/acceleration.First resistor 301 is connected to the 1st capacitor 304 receiving coupling unit 120.The second and the 3rd resistor 302,303 is the two-terminal-grounding of first resistor 301.First capacitor 304 is connected to the input end of first amplifier 306.One second capacitor 307 is the output ground connection of first amplifier 306.One the 4th resistor 308 is connected to the output of first amplifier 306 on 24 volts of positive voltages.
Equalizing device 214 comprises an equalizing circuit 310.In preferred embodiment, equalizing circuit 310 comprises one first NPN transistor 311.One the 5th resistor 312 and one the 3rd capacitor 313 of series connection link to each other the collector of first NPN transistor 311 with base stage, 314 of one the 6th resistors receive this collector+24 volts of voltage on.The the 7th and the 8th resistor 315,316 of series connection is the grounded emitter of first NPN transistor 311.First inductance 317 and the 4th capacitor 318 and 315,315 parallel connections of the 7th and the 8th resistor are as shown in the figure.The 5th capacitor 319 is connected to equalizing circuit 310 remainder of pick-up unit 214.The 5th resistance 312 and the 3rd capacitor 313 are formed the first voltage gain part X
c, the 7th resistor 315 and first inductance 317 are formed the second voltage gain part X
eThe total voltage gain of equalizing device 212 is approximately equal to X
c/ X
e
Comparison means 216 comprises that reception one shows the device of the reset signal of reset condition, receives the output of equalizing device 214, correspondingly produces a frequency lock signal when not having reset signal.
The device that comparison means 216 also comprises the device that detects the electromagnetic wave amplitude and correspondingly produces the signal of the detection that a signal that is detected produces comprises that the voltage multiplying rectifier device is to improve the sensitivity of comparison means 216.
The voltage multiplying rectifier device comprises one first Schottky-barrier diode 320, and this diode is connected between the 5th capacitor 319 and the ground wire.One second Schottky-barrier diode 321 is connected to the anode of first schottky diode 320, the anode of second Schottky-barrier diode 321 is connected to first comparison means 216, the 6th capacitor 323 the contact ground connection between second Schottky-barrier diode 321 and the 9th resistor 322 by the 9th resistor 322.
Comparison means comprises that also an automatic nothing records the baseline circuit or from clearing device 388, this returns device 388 to comprise a four-operational amplifier 364 certainly.
Comparison means 216 also comprise detect signal and threshold ratio device.Described comparison means 216 comprises one first operational amplifier 326 and 1 the tenth resistor 328.The tenth resistor 328 is connected to the output of first operational amplifier 326 the negative input end of first operational amplifier 326.The 11 resistor 330 is linked this negative input end+2 volts of power supplys.
Anti-phase/not anti-phase multiplying arrangement 218 comprises one second operational amplifier 332.The 12 resistor 334 is connected to the output of second operational amplifier 332 the negative input end of operational amplifier 332.The 13 resistor 336 is connected to the output of first operational amplifier 326 negative input end of second operational amplifier 332.The positive input terminal of second operational amplifier 332 is connected on 0.6 volt of power supply.The 14 resistor 338 is connected the output of first operational amplifier 326 with integrating gear 220.One first Zener diode 340 is the output ground connection of first operational amplifier 326.
The output of described second operational amplifier 332 is connected to the output terminal of first switch 344, and the control end of first switch 344 is connected to integrating gear 220 by one the 7th capacitor 346.The input end of first switch 344 is connected to integrating gear 220 by 1 the 15 resistor 348.
This integrating gear 220 comprises that one the 3rd operational amplifier 350, the 8th capacitor 352 is connected to the output of the 3rd operational amplifier 350 the negative input end of operational amplifier 350.The positive input end of the 3rd operational amplifier 350 is linked on 0.6 volt of power supply.
Switchgear 224 comprises second and third switch 360,362.The control end of second and third switch 360,362 is connected to noise reduction apparatus 222.The input end grounding of second switch 360.The output terminal of second switch 360 is connected on the negative input end of the 3rd operational amplifier 350.
The input end of the 3rd day pass 362 is connected on the negative input end of four-operational amplifier 364 by 1 the 16 resistor.The output terminal of the 3rd switch 362 is linked the output terminal of first operational amplifier.The positive input end of four-operational amplifier 364 is connected to 1 volt of power supply.The output of four-operational amplifier 364 is connected to its negative input end by one the 9th capacitor 368.The output of four-operational amplifier 364 also is connected on the positive input end of first operational amplifier by the 17 resistor 370.
Reduce noise device 222 and comprise third and fourth comparer 372,374.The positive input end of third and fourth comparer 372,374 is connected to+5 volts of power supplys.The 18 resistor 376 is connected to the incoming line that resets to the negative input end of the 3rd comparer 372.One the 9th resistor 378 is connected to this incoming line that resets+20 volts of power supplys on.The tenth capacitor 380 is the negative input end grounding of the 3rd comparer 372.The 12 resistor 382 is received the slope incoming line to the negative input end of the 4th comparer 374.One the 21 resistor 384 is connected to the slope incoming line+20 volts of power supplys.The 11 capacitor 386 is the negative input end ground connection of the 4th comparer 374.
Industrial application.See also accompanying drawing.When operation, RF linear position transducer 102 can be measured the linear extension length of hydraulic cylinder 108, and speed and acceleration are with thinking that external control system provides feedback information.
External control system is used to the information from a plurality of relevant hydraulic cylinders of each sensor.Each sensor comprises a radiating portion, a receiving unit and a control section.Yet this control device of sensor can be arranged on the part of interior female control of same microprocessor or main control unit.
This microprocessor is preferably in position, speed and the acceleration of a hydraulic cylinder of a control loop period detecting.This control loop is generally in microsecond, for example 20 microseconds.
Each sensor all will be started working at synchronization.Intersect or cut condition mutually and measure all after dates when detecting a slope, controller will be read counter.After each circulation, controller will calculate position, speed and the acceleration of each hydraulic cylinder and the data storing that records in storer.
Receiving unit comprises a comparison means 216, in order to receive the electromagnetic wave signal from hydraulic cylinder inside.This comparison means 216 comprises the resonance frequency that receives a reset signal and response hydraulic cylinder and does not have reset signal and produce a frequency lock signal.So just can eliminate the possibility of flase drop hydraulic cylinder resonance frequency.
See also Fig. 3 now.First operational amplifier 326 detect signal and threshold signal compare.First operational amplifier during greater than threshold value (at the signal of negative input end), detects resonance frequency at the signal of positive input terminal.
When resetting, there is not detected signal in 320,321 places at the detector diode.From clearing device 388 voltage of first operational amplifier, 326 positive input terminals is adjusted to 2 volts and the voltage of first operational amplifier output is adjusted to 1 volt.Like this, no matter the bias voltage of diode, temperature drift are how, the baseline voltage of set automatically when nothing detects signal, thus avoided relevant therewith dc error.Can make working sensor in the detection voltage more much smaller from clearing device 388 than diode bias voltage.
Other aspects of the present invention, purpose and advantage can be by reading over accompanying drawing, instructions and appended claims and reach better understanding.
Claims (12)
1, a kind of device that can detect the linear position of piston mobile in the hydraulic cylinder cylinder barrel, piston rod, this device comprises:
Produce an electromagnetic wave signal and electromagnetic wave signal is sent to part in the hydraulic cylinder, this electromagnetic signal has the frequency that can change between predetermined minimum value and maximal value;
Survey the device of the signal after the also corresponding generation one of electromagnetic wave signal is amplified in the described hydraulic cylinder;
Reception shows the receiving unit of the reset signal of reset condition, and the signal after its receive to amplify compares the signal after this amplifications and a steady state value of being scheduled to and do not having correspondingly to produce a frequency lock signal under the situation of reset signal;
Receive described frequency lock signal and and then measure the device of the position of piston and piston rod.
2, device as claimed in claim 1 is characterized in that, described piston, piston rod and cylinder barrel form an adjustable length coaxial cavity, and transmitting in this coaxial cavity is the transverse electromagnetic wave signal.
3, device as claimed in claim 1 is characterized in that, described position measuring device comprises the device of the resonance frequency of measuring described coaxial cavity, and wherein the position of piston and piston rod is measured as the function of described resonance frequency.
4, device as claimed in claim 1 is characterized in that, described comparison means comprises the device that detects described electromagnetic wave signal amplitude and correspondingly produce a detected signal.
5, device as claimed in claim 1 is characterized in that, described comparison means comprises an operational amplifier, and the device of the intact signal of described generation frequency lock links to each other with the input end of described operational amplifier.
6, device as claimed in claim 5 is characterized in that, described comparison means comprises an operational amplifier, and described operational amplifier links to each other with the positive input terminal of described operational amplifier by a resistor.
7, device as claimed in claim 1 is characterized in that, the device that produces the frequency lock signal comprises:
One operational amplifier;
One is connected to the switch of the negative input end of described operational amplifier, and this switch can be accepted reset signal;
One capacitor, it is connected between the negative input end and output terminal of described operational amplifier;
The output terminal of wherein said operational amplifier is connected on the described comparison means.
8, device as claimed in claim 7 is characterized in that, described comparison means comprises an operational amplifier, and the output terminal of described operational amplifier links to each other with the positive input terminal of described operational amplifier by a resistor.
9, device as claimed in claim 1 is characterized in that, described comparison means comprises the voltage multiplying rectifier device, in order to improve the sensitivity of described comparison means.
10, device as claimed in claim 9 is characterized in that, described voltage multiplying rectifier device comprises first and second diodes, and the negative electrode of described first diode is linked on the anode of described second diode.
11, device as claimed in claim 10, wherein said the one the second diodes are Schottky-barrier diodes.
12, a kind of piston mobile in a hydraulic cylinder body and device of piston rod linear position of detecting, it comprises:
Produce an electromagnetic wave signal and described electromagnetic signal is transmitted into device in the described hydraulic cylinder, described electromagnetic signal has the frequency that can change between a predetermined maximum value and minimum value, be used to survey the electromagnetic wave signal in the hydraulic cylinder, and corresponding generation one amplifying signal, receive the signal after the described amplification, detect the amplitude of the signal after the described amplification, and the device of corresponding generation one detection signal;
Reception one shows the reset signal of reset condition, receives detected signal, a described detected signal and a steady state value of being scheduled to are compared, and correspondingly at the device that does not have to produce under the situation of reset signal a frequency lock signal;
Receive described frequency lock signal and correspondingly measure the resonance frequency of described coaxial cavity and measure as the piston of the function of resonance frequency and the device of piston rod position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 93118882 CN1102253A (en) | 1993-10-23 | 1993-10-23 | Linear position sensor with equalizing means |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 93118882 CN1102253A (en) | 1993-10-23 | 1993-10-23 | Linear position sensor with equalizing means |
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| Publication Number | Publication Date |
|---|---|
| CN1102253A true CN1102253A (en) | 1995-05-03 |
Family
ID=4992696
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|---|---|---|---|
| CN 93118882 Pending CN1102253A (en) | 1993-10-23 | 1993-10-23 | Linear position sensor with equalizing means |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393295A (en) * | 2011-09-08 | 2012-03-28 | 浙江九隆机械有限公司 | Testing device of braker |
| CN102628681A (en) * | 2011-01-20 | 2012-08-08 | 通用电气公司 | Sensor probe and method of assembling a sensor probe |
| CN101275597B (en) * | 2007-03-30 | 2012-10-10 | Smc株式会社 | Position-control mechanism for a single-action pneumatic cylinder |
| EP3150864A1 (en) * | 2015-10-02 | 2017-04-05 | Liebherr-Elektronik GmbH | Device and method for determining the position of a cylinder piston |
| WO2020186402A1 (en) * | 2019-03-15 | 2020-09-24 | 江苏弘开传感科技有限公司 | Cavity length measuring device for dielectric cavity |
| CN115487380A (en) * | 2017-12-21 | 2022-12-20 | 赛诺菲 | Transmission of data relating to injection device use using passive RF modulation |
-
1993
- 1993-10-23 CN CN 93118882 patent/CN1102253A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101275597B (en) * | 2007-03-30 | 2012-10-10 | Smc株式会社 | Position-control mechanism for a single-action pneumatic cylinder |
| CN102628681A (en) * | 2011-01-20 | 2012-08-08 | 通用电气公司 | Sensor probe and method of assembling a sensor probe |
| CN102393295A (en) * | 2011-09-08 | 2012-03-28 | 浙江九隆机械有限公司 | Testing device of braker |
| EP3150864A1 (en) * | 2015-10-02 | 2017-04-05 | Liebherr-Elektronik GmbH | Device and method for determining the position of a cylinder piston |
| CN115487380A (en) * | 2017-12-21 | 2022-12-20 | 赛诺菲 | Transmission of data relating to injection device use using passive RF modulation |
| WO2020186402A1 (en) * | 2019-03-15 | 2020-09-24 | 江苏弘开传感科技有限公司 | Cavity length measuring device for dielectric cavity |
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