JP2004219320A - Sensor having error correction function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor system capable of separating a sensor for detecting position displacement and displacement in other physical quantities from a transducer that converts a detection signal to an electric signal that can be processed as a specific measurement unit or a numerical value and is independent of the sensor spatially for exchanging in a state, where error processing peculiar to the sensor can be made. <P>SOLUTION: The sensor 1 for detecting the displacement in physical quantities is connected (5) to the transducer 2 that converts the detection signal to the electric signal that can be processed as the specific measurement unit or numerical value and is independent of the sensor spatially. A memory chip 4 having storage contents, based on error information peculiar to the sensor, is mounted and the storage contents can be transmitted to the transducer. When the sensor is connected to a power supply via the sensor itself or the transducer, the storage contents, based on the error information in the memory chip, can be read/supplied to the transducer immediately after the power supply is turned on. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２３】
この方式を位相差変換と呼び、図７において、分図（Ａ）は励磁電圧ＡＳｉｎωｔと、それを搬送波とするθ変位に対応した（１）、（２）式の各右辺の電圧波形図、同（Ｂ）はＡＳｉｎωｔのグラフと特定の位相（θ，ｘ）を含む右辺の正弦波、この場合は、ａＳｉｎ（ωｔ−θ，ｘ）のグラフとの時間関係を示す波形図であり、更に同（Ｃ）はこれらの波形図の根拠となる数式的推移を示したものである。なお、進み位相波ａＳｉｎ（ωｔ＋θ，ｘ）の場合、そのグラフは破線で示した遅れ位相波ａＳｉｎ（ωｔ−θ，ｘ）のグラフと対称的に、実線で示したＡＳｉｎωｔのグラフよりも（θ，ｘ）だけ時間的に先行した正弦波として想起できるであろう。
【００２４】
図７Ｂのグラフから明らかなとおり、θ又はｘを求めるにはＡＳｉｎωｔグラフのゼロクロス点から、ａＳｉｎ（ωｔ−θ，ｘ）又はａＳｉｎ（ωｔ＋θ，ｘ）グラフのゼロクロス点までの時間をカウントすればよいことが理解されるであろう。このカウントは進相、遅相いずれの位相で求めてもよいが、コイルＬ１〜Ｌ４等に温度変化によるインピーダンス変化が生じている場合，それによる位相変動誤差±ｄはωｔに付随するため、ここでは詳述しないが上記の進相、遅相の両正弦波グラフの双方を用いて処理することにより、この±ｄを容易に消去することができる。
【００２５】
以上のようにして、コイルＬ１〜Ｌ４に対する偏心磁性体１１又は磁性体配列棒１６の位置変位を、計算上きわめて精密に（例えば、３６０度又は１ピッチ間隔内を２^１６＝６５５３６分割し、角度の場合なら、約１８２分の１度の分解能により）算出し得たとしても、コイルＬ１〜Ｌ４自体の製造誤差、偏心磁性体１１又は磁性体配列棒１６における製造誤差等によるセンサ本来の誤差要因と，被検体へのセンサ取り付け状態に伴う誤差要因等が重なり、測定値には特有の誤差を含むことになる。
【００２６】
これらの誤差は従来、センサ製造時又は被検体へのセンサ取り付け時において検証され、それらの記憶値を変換器中において保持していたものであるが、本実施例においては次のようなルックアップテーブルとしてメモリチップに記憶させ、それをセンサ本体内に装備することにより、センサと変換器とを互いに独立した互換品として扱えるようにしたことは前述した通りである。
【００２７】
図８は、センサから出力された検出値を用い、変換器で３６０度を２^１６＝６５５３６分割して算出された角度θ（ｘｘｘｘｘ）をアドレスとして、これに対する誤差Δθ（ｘｘｘｘｘ）の値を一覧表化したものである。図２を参照して、これら６５５３６個の誤差Δθ値はアドレスθと共に、電源オン時において、メモリチップ４からシリアルデータとして読み出され、変換器２に供給されて保持される。以後変換器２はセンサ１から検出値が送出されるたびにθ演算を行い、ルックアップテーブルそのものとして記憶した対応する誤差データを、そのθ値（アドレス）から読み出し、補正演算することができる。
【００２８】
図９は、同じく変換器で３６０度を２^１６＝６５５３６分割して算出された角度θ（ｘｘｘｘｘ）をアドレスとして、これに対する既知の誤差Δθ（ｘｘｘｘｘ）の値を加えることにより算出された真の値（最も確からしい値）Θ（ｘｘｘｘｘ）を一覧表化したものである。図２を参照して、これら６５５３６個の真の値Θまたは離散データは、電源オン時において、メモリチップ４からシリアルデータとして読み出され、変換器２に供給されて保持される。以後変換器２はセンサ１から検出値が送出されるたびにθ演算を行い、ルックアップテーブルそのものとして記憶した対応する真の値Θを、そのθ値（アドレス）から読み出すことができる。
【００２９】
上記のようなメモリ構成は、センサの測定ピッチが角度θでなく直線変位ｘである場合も、１ピッチ＝Ｐ［ｍｍ］とし、そのＰを上述のように６５５３６分割した分解能における計測において用い得ることは明らかである。
【００３０】
【発明の効果】
以上述べたとおり、本発明は物理量の変位を検出するセンサにおいて、固有の誤差情報に基づく記憶内容を有するメモリチップを装備し、空間的に分離した変換器に対しては、まずその記憶内容を送出してから検出値を出力する。変換器は記憶内容が誤差情報そのものであれば、以後センサから受信する検出値に基づいて算出した値（θ，ｘ）をその誤差情報に基づいて補正し、記憶内容が真の値であれば、それと読み替えるようにしたものであるため、センサと電気信号処理用の変換器とを、センサ単独又は設置条件も含めたセンサ固有の誤差処理が可能な状態において、個々に切り離して交換可能としたセンサシステムを構成することができる。
【００３１】
換言すれば、変換器に対してセンサは互換性をもつことになり、複数のセンサについての信号受信又は誤差校正を一つの変換器により行えることになる。
【図面の簡単な説明】
【図１】従来のセンサ／変換器の関係を模式的に示す接続図である。
【図２】本発明の実施形態におけるセンサ／変換器の関係を、模式的に示す接続図である。
【図３】図２に示した実施形態におけるセンサの具体的な外観形状の一例を示す斜視図である。
【図４】回転変位検出型のセンサの具体的な外観形状の一例を示す斜視図である。
【図５】本発明のセンサに適用される好ましい回転変位検出原理を説明するために、その構造の模式的な断面略図（Ａ）、及びコイルＬ１− Ｌ３、Ｌ２− Ｌ４の差動接続（Ｂ）と、演算増幅器より構成されるそれらの差動回路（Ｃ）を示したものである。
【図６】本発明のセンサに適用される好ましい直線変位検出原理を説明するために、その構造の模式的な断面略図（Ａ）、及びコイルＬ１− Ｌ３、Ｌ２− Ｌ４の差動接続（Ｂ）と、演算増幅器より構成されるそれらの差動回路（Ｃ）を示したものである。
【図７】コイルＬ１〜Ｌ４への励磁電圧ＡＳｉｎωｔと、それを搬送波とするθ変位に対応したＬ１− Ｌ３差動電圧及びＬ２− Ｌ４差動電圧の波形図（Ａ）、励磁電圧ＡＳｉｎωｔのグラフと特定の位相（θ，ｘ）を含む加法定理（正弦の法則）から得られたａＳｉｎ（ωｔ−θ，ｘ）のグラフとの時間関係を示す波形図（Ｂ）、及びこれらの波形図の根拠となる数式的推移（Ｃ）を示したものである。
【図８】３６０度を２^１６＝６５５３６分割し、センサから出力された検出値に基づき変換器により算出された角度値θ（ｘｘｘｘｘ）をアドレスとして、これに対する誤差Δθ（ｘｘｘｘｘ）の値を一覧表化したものである。
【図９】図８と同じく３６０度を２^１６＝６５５３６分割し、センサから出力された検出値に基づき変換器により算出された角度検出値θ（ｘｘｘｘｘ）をアドレスとして、これに対する既知の誤差Δθ（ｘｘｘｘｘ）の値を加えることにより算出された真の値（最も確からしい値）Θ（ｘｘｘｘｘ）を一覧表化したものである。
【符号の説明】
１ センサ（直線変位検出型）
１ａ プローブ部
２ 変換器
４ メモリチップ
５ ケーブル
６ 磁性体配列針６
７，８ 外周ネジ
９ ケーブル
１０ 回転変位検出型センサ
１０ａ センサ１０本体
１０ｂ フランジ部
１１ 偏心磁性体
１２ 中心シャフト
１３ スペーサ
１４ 電気ケーブル
１５ 極鉄心
１６ 磁性体配列棒
１６ａ 強磁性体
１６ｂ 反磁性体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sensor with an error correction function, and more particularly to a function for improving the accuracy of a sensor used as a pair with a converter for its detection signal.
[0002]
[Prior art]
In general, the accuracy of a sensor for detecting a displacement of a physical quantity is degraded by including a device difference due to a manufacturing process, such as an error unique to an element and an element arrangement. In order to increase the accuracy of such a sensor, a calibration operation is performed and error correction is performed in comparison with the absolute accuracy. This correction processing physically modifies the components of the sensor or performs electrical data processing. Has been implemented by
[0003]
In this error correction, since the operation of correcting the components is difficult and takes a lot of trouble, it is mainly performed by electrical data processing. This electrical processing is usually performed in a signal processing converter paired with the sensor described above (for example, see Patent Document 1). Therefore, when replacing the sensor, it is necessary to also replace the converter having the correction function relating only to the error of the sensor, and the same can be said when the converter is to be replaced. In the case of a small sensor, the sensor and the converter are always handled as a pair at the time of maintenance or replacement of a failure, which is inconvenient and uneconomical.
[0004]
[Patent Document 1]
JP-A-10-229478 (refer to [0034]-[0042] stage)
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a sensor for detecting a displacement of a position displacement or other physical quantity, and to convert a detection signal into an electric signal that can be processed as a predetermined measurement unit or a numerical value, the sensor is spatially independent. An object of the present invention is to provide a sensor system in which a converter can be individually separated and replaced in a state where error processing unique to the sensor can be performed.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a sensor that detects a displacement of a physical quantity, and converts a detection signal into an electric signal that can be processed as a predetermined measurement unit or a numerical value. A sensor which is connected to an independent converter, is provided with a memory chip having storage contents based on error information unique to the sensor, and the storage contents can be transmitted to the converter.
[0007]
According to the configuration of the present invention described above, when a sensor fails, only the sensor is removed and the sensor is removed and replaced with a new one while leaving the converter alone. By rewriting to the error information, the sensor system can be easily reconstructed. Conversely, when the converter fails, the sensor may be taken out and the converter alone taken out and repaired, or replaced with a new one having the same specification.
[0008]
Secondly, when the sensor is connected to a power supply via itself or a converter, the storage contents based on the error information in the memory chip are read out to the converter immediately after power-on.・ It is intended to be supplied. That is, the error information read and supplied to the converter immediately after the power is turned on is used consistently for subsequent correction of the sensor detection signal in the converter.
[0009]
Thirdly, the present invention is such that the contents stored in the memory chip comprise correction values of a detection signal based on the error information. That is, if an error corresponding to the detected value of the sensor is checked in advance, and a correction value obtained by appropriately executing a correction operation corresponding to the error is directly stored in a memory chip, an actual measurement detection signal of the sensor is obtained. The converter which has received and calculated the displacement amount can output a signal representing the stored true (most likely) value using the calculated displacement amount as an address. In this case as well, the sensor and the converter Can be used interchangeably with each other.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
In describing an embodiment of the present invention, FIG. 1 schematically shows a conventional sensor / converter relationship. In this case, the sensor 1 is a linear position displacement detector in which a thin rod-shaped magnetic response rod (not shown) which is relatively movable in the length direction of the probe portion is inserted from the tip portion of the probe portion 1a. The output line is electrically fixedly connected to the converter 2, and the sensor 1 and the converter 2 are calibrated as a pair, and other relations in which the sensor 1 and the converter 2 are restricted to each other are indicated by half brackets 3.
[0011]
On the other hand, in the embodiment of the present invention, as shown in FIG. 2, a memory chip 4 which basically stores error information with respect to the actual output of the sensor 1 is built in the main body of the sensor 1, The error information is supplied to the converter 2 as serial data via the cable 5, preferably when the power supply to the sensor 1 is turned on directly or via the converter 2. Thus, it is clear that the sensor 1 and the transducer 2 are mutually compatible.
[0012]
FIG. 3 is a perspective view showing a specific external shape of the sensor 1 in the embodiment shown in FIG. A cylindrical cavity (not shown) opened from the tip 1c is formed in the probe portion 1a protruding from the main body sheath portion 1b of the sensor 1, and, for example, four solenoid coils (functions thereof) are formed in the cylindrical cavity. Will be described later in detail). Further, a magnetic material array needle 6 which movably penetrates the coils is inserted into the cylindrical cavity, and the probe portion 1a is fixed to the probe 6 with its base 6a fixedly supported by some object. Relative movement is possible. The memory chip 4 (FIG. 2) is provided in the body sheath 1b (not shown) so as not to affect the sensor function.
[0013]
Outer peripheral screws 7 and 8 are formed at appropriate positions in the probe section 1a, and a cable 9 containing a signal line and a power supply line connected to the above-described converter and the like extends from a rear projection 1d of the main body sheath section 1b. ing. Thus, when the outer peripheral screws 7 and 8 of the probe section 1a are attached and fixed to any exterior body or a mounting attachment (not shown) which movably accommodates or equips the subject, preferably, The error of the sensor (integrated with the subject) is verified by various methods, and the error information confirmed by this is written in the memory chip 4. This memory chip is constituted by a ROM so that the internal information is not erased by reading each time.
[0014]
FIG. 4 is a perspective view showing a specific external shape of the rotational displacement detection type sensor 10 while the sensor 1 in the embodiment shown in FIGS. 2 and 3 is a linear displacement detection type. is there. The main body 10a of the sensor 10 is cup-shaped, and has, for example, four solenoid coils (the function of which will be described in detail later) arranged in an annular shape along the inner peripheral surface thereof, and is circular from the opening of the flange portion 10b. An eccentric magnetic body 11 having a cross section is rotatably inserted, and occupies an appropriate angular position by a central shaft 12 connected to a subject whose rotational displacement is to be detected. Reference numeral 13 denotes a spacer fixed to the outer periphery of the eccentric magnetic body 11, and a spacer fitted to the flange portion 10b. Reference numeral 14 denotes an electric cable.
[0015]
Also in the case of the rotational displacement detection type sensor 10, the memory chip is preferably provided inside the main body 10a (not shown) so as not to affect the sensor function. Thus, when the flange portion 10b is attached and fixed to any external body or an attachment (not shown) for rotatably storing or equipping the subject, the sensor after the attachment is attached similarly to the case of the linear displacement sensor. Is verified, and the error information is written into the memory chip.
[0016]
【Example】
FIG. 5 and FIG. 6 show a preferred detection principle employed by the sensor of the present invention with respect to a position displacement, which is one of the displacements of the physical quantity. Here, first, referring to FIG. The principle of displacement detection will be described. FIG. 5A is a schematic cross-sectional schematic view showing the principle of the rotational displacement detection sensor 10. The coils L1, L2, L3, and L4 arranged in the sensor body (yoke) at equal intervals in a ring shape are all central axes. , And the distance between the extreme surfaces thereof and the peripheral surface of the eccentric magnetic body 11 is different depending on the angular position of the magnetic body 11.
[0017]
The coils L1, L2, L3, and L4 are connected to an AC power supply (not shown) as four secondary coils (induction type) arranged so as to mutually induce the primary coil, or connected in parallel via an appropriate resistor. By using an independent coil (impedance type) that is connected, a sine wave voltage is induced in an alternating inversion phase in the coil arrangement order, or is applied in the same phase, and is applied in accordance with the distance from the peripheral surface of the eccentric magnetic body 11 described above. A different voltage between coil ends is realized by a change in magnetic flux or inductance passing through the coil. FIG. 5B shows a circuit for differentially taking out such a voltage between coil ends as a sensor output in the set L1-L3 and the set L2-L4 to the converter C side.
[0018]
Assuming that the angle position (lowest eccentric position) of the eccentric magnetic body 11 in FIG. 5A is θ = 0 and the clockwise rotation in the drawing is the positive direction, the operational amplifier OA for L1-L3 in FIGS. The output Y of 1-3) becomes a value obtained by multiplying the sine wave Sinωt as the excitation signal by the coefficient, that is, the displacement aCosθ of the amplitude, and the output X of the L2-L4 operational amplifier OA (2-4) becomes the excitation signal. This shows that the differential circuit is configured to have a value obtained by multiplying the sine wave Sinωt by the coefficient, that is, the amplitude displacement aSinθ. Therefore, it will be understood that one rotation of the eccentric magnetic body 11 corresponds to a 360-degree displacement of θ.
[0019]
FIG. 6A is a schematic cross-sectional schematic view showing the principle of the sensor 1 for linear displacement detection. The coils L1, L2, which are linearly adjacent to each other in the sensor probe section and are arranged so as to mutually induce with a primary coil (not shown). L3 and L4 surround the magnetic array rod 16 coaxially and relatively displaceable in the axial direction. The magnetic material array rod 16 is formed by alternately arranging the ferromagnetic material 16a and the diamagnetic material 16b in such a manner that the total length of the coils L1 to L4 (formally, four times the pitch between the coils) is one pitch. When the coils (for example, L3) correspond to the center of the ferromagnetic material 16a, the coil (for example, L1) at a position one pair away from the coil (for example, L1) corresponds to the center of the diamagnetic material 16b. It has become.
[0020]
In this case, the coils L1, L2, L3, and L4 also induce or apply a predetermined sinusoidal voltage, as in the case of the rotational displacement sensor, and pass through the coil in accordance with the position relative to the magnetic material array rod 16 described above. FIG. 6B is a diagram illustrating a case where the voltage between the coil ends is changed according to the change of the magnetic flux or the inductance, and the voltage between the coil ends is set as the sensor output in the set of L1-L3 and the set of L2-L4. The circuit for taking out differentially is shown on the side.
[0021]
The axial position (position corresponding to L3-ferromagnetic material 16a, position corresponding to L1-diamagnetic material 16b) of the magnetic material array rod 16 in FIG. 6A is set to x = 0, and the rod is moved to the left in the drawing, for example. 6B and 6C, the output Y of the L1-L3 operational amplifier OA (1-3) is a value obtained by multiplying a sinusoidal wave Sinωt as an excitation signal by a fluctuating coefficient, that is, an amplitude displacement aCosx. A differential circuit is configured such that the output X of the L2-L4 operational amplifier OA (2-4) has a value obtained by multiplying a sine wave Sinωt as an excitation signal by a variable coefficient, that is, an amplitude displacement aSinx. Is shown. Therefore, it will be understood that one pitch displacement (actual size) of the magnetic array rod 16 can be treated as x (p) = 2π [rad] (360 degrees).
[0022]
Expressions of Y and X obtained as described above: Y = aCos (θ, x) · Sinωt (1)
X = aSin (θ, x) · Sinωt (2)
(In these equations, (θ, x) in the parentheses of the Cos or Sin function representing the displacement of the coefficient, that is, the amplitude, is θ for angular displacement and x for linear displacement. Is used as an arithmetic circuit for calculating the angular displacement θ, the sine function Sinφ of the digital phase value φ sequentially increasing from 0 and the cosine in equations (1) and (2), respectively. Multiply by the function Cosφ,
・ Sinφ ・ Cosθ-Cosφ ・ Sinθ = 0 ・ ・ (3)
At this point, there is a known RD conversion method that specifies θ by setting θ = φ, but this method has a problem that a clock delay occurs when φ is tracked and counted, resulting in poor response. Therefore, in this embodiment, aSin (θ, x) · Cosωt is obtained by converting Sinωt in equation (2) into Cosωt on the circuit, and the addition theorem of the trigonometric function is directly applied. Ie

[0023]
This method is referred to as phase difference conversion. In FIG. 7, FIG. 7 (A) is a voltage waveform diagram on each right side of the equations (1) and (2) corresponding to the excitation voltage ASinωt and θ displacement using the same as a carrier wave. (B) is a waveform diagram showing a time relationship between a graph of ASinωt and a sine wave on the right side including a specific phase (θ, x), in this case, a graph of aSin (ωt−θ, x). FIG. 7C shows a mathematical transition which is the basis of these waveform diagrams. In the case of the leading phase wave aSin (ωt + θ, x), the graph is symmetrical to the graph of the lagging phase wave aSin (ωt−θ, x) shown by the broken line, and is more (θ) than the graph of ASinωt shown by the solid line. , X) could be recalled as a sine wave temporally preceding.
[0024]
As is clear from the graph of FIG. 7B, in order to obtain θ or x, the time from the zero cross point of the ASinωt graph to the zero cross point of the aSin (ωt−θ, x) or aSin (ωt + θ, x) graph may be counted. It will be appreciated. This count may be obtained in any of the leading phase and the lagging phase. However, if an impedance change occurs due to a temperature change in the coils L1 to L4 and the like, a phase variation error ± d due to the variation is accompanied by ωt. Although not described in detail, by performing processing using both of the above-described sine wave graphs of the leading phase and the lagging phase, ± d can be easily eliminated.
[0025]
As described above, the positional displacement of the eccentric magnetic substance 11 or the magnetic substance array rod 16 with respect to the coils L1 to L4 can be calculated very precisely (for example, 360 degrees or one pitch interval is divided into 2 ¹⁶ = 65536, and the angle is divided into angles. In the case of (1), even if the calculation can be performed with a resolution of about 182 degrees, the original error factor of the sensor due to the manufacturing error of the coils L1 to L4 itself, the manufacturing error in the eccentric magnetic body 11 or the magnetic array bar 16 and the like And an error factor or the like associated with a state in which the sensor is attached to the subject, and the measured value includes a specific error.
[0026]
Conventionally, these errors are verified at the time of manufacture of the sensor or at the time of attaching the sensor to the subject, and the stored values are stored in the converter. In the present embodiment, the following lookup is performed. As described above, the sensor and the converter can be handled as mutually independent compatible products by storing the data in the memory chip as a table and mounting it in the sensor body.
[0027]
FIG. 8 shows a list of values of an error Δθ (xxxxxx) corresponding to an angle θ (xxxxxx) calculated by dividing 360 degrees into 2 ¹⁶ = 65536 by a converter using detected values output from the sensor. It is tabulated. Referring to FIG. 2, these 65536 error Δθ values, together with address θ, are read out from memory chip 4 as serial data when power is turned on, supplied to converter 2 and held. Thereafter, the converter 2 performs the θ calculation every time a detection value is sent out from the sensor 1, reads out the corresponding error data stored as the lookup table itself from the θ value (address), and can perform the correction calculation.
[0028]
FIG. 9 shows the true value calculated by adding the value of the known error Δθ (xxxxxx) to the angle θ (xxxxxx) calculated by dividing 360 degrees by 2 ¹⁶ = 65536 using the converter as an address. This is a list of values (most likely values) 値 (xxxxxx). Referring to FIG. 2, these 65536 true values Θ or discrete data are read out as serial data from memory chip 4 when the power is turned on, supplied to converter 2 and held. Thereafter, the converter 2 performs a θ calculation each time a detection value is transmitted from the sensor 1, and can read out the corresponding true value 記憶 stored as the lookup table itself from the θ value (address).
[0029]
Even when the measurement pitch of the sensor is not the angle θ but the linear displacement x, the memory configuration as described above can be used for measurement at a resolution of 65536 divided as described above, with 1 pitch = P [mm]. It is clear.
[0030]
【The invention's effect】
As described above, the present invention provides a sensor for detecting a displacement of a physical quantity, which is provided with a memory chip having a storage content based on unique error information, and first stores the storage content for a spatially separated converter. After sending, the detection value is output. If the stored content is the error information itself, the converter corrects the value (θ, x) calculated based on the detection value received from the sensor thereafter based on the error information, and if the stored content is a true value, The sensor and the converter for electric signal processing can be individually separated and replaced in a state in which error processing unique to the sensor including the sensor alone or the installation condition is possible, since the sensor and the converter for electric signal processing can be replaced with each other. A sensor system can be configured.
[0031]
In other words, the sensors are compatible with the transducers, and signal reception or error calibration for a plurality of sensors can be performed by one transducer.
[Brief description of the drawings]
FIG. 1 is a connection diagram schematically showing a conventional sensor / converter relationship.
FIG. 2 is a connection diagram schematically illustrating a sensor / converter relationship in the embodiment of the present invention.
FIG. 3 is a perspective view showing an example of a specific external shape of the sensor in the embodiment shown in FIG.
FIG. 4 is a perspective view showing an example of a specific external shape of a rotational displacement detection type sensor.
FIG. 5 is a schematic cross-sectional view (A) of the structure and a differential connection (B) of coils L1-L3, L2-L4, for explaining a preferable rotation displacement detection principle applied to the sensor of the present invention. ) And their differential circuits (C) composed of operational amplifiers.
FIG. 6 is a schematic cross-sectional view (A) of the structure and a differential connection (B) of coils L1-L3 and L2-L4 for explaining a preferred principle of linear displacement detection applied to the sensor of the present invention. ) And their differential circuits (C) composed of operational amplifiers.
FIG. 7 is a waveform diagram (A) of the excitation voltage ASinωt to the coils L1 to L4, the L1-L3 differential voltage and the L2-L4 differential voltage corresponding to the θ displacement using the excitation voltage ASinωt, and a graph of the excitation voltage ASinωt. (B) showing a time relationship between a graph of aSin (ωt−θ, x) obtained from an additive theorem (sin's law) including a specific phase (θ, x), and FIG. It shows a mathematical transition (C) as a basis.
FIG. 8 divides 360 degrees into 2 ¹⁶ = 65536 and lists values of an error Δθ (xxxxxx) corresponding to an angle value θ (xxxxxx) calculated by a converter based on a detection value output from a sensor as an address; It is tabulated.
9 divides 360 degrees into 2 ¹⁶ = 65536 in the same manner as in FIG. 8 and uses a detected angle θ (xxxxxx) calculated by a converter based on a detected value output from a sensor as an address, and a known error Δθ with respect to this. It is a table listing true values (most probable values) Θ (xxxxxx) calculated by adding the values of (xxxxxx).
[Explanation of symbols]
1 sensor (linear displacement detection type)
1a Probe section 2 Converter 4 Memory chip 5 Cable 6 Magnetic substance arrangement needle 6
7, 8 Outer thread 9 Cable 10 Rotational displacement detection type sensor 10a Sensor 10 main body 10b Flange part 11 Eccentric magnetic body 12 Center shaft 13 Spacer 14 Electric cable 15 Pole core 16 Magnetic material arrangement rod 16a Ferromagnetic material 16b Antimagnetic material

Claims (3)

A sensor for detecting a displacement of a physical quantity, wherein the sensor is connected to a transducer spatially independent of the sensor for converting a detection signal into an electric signal that can be processed as a predetermined measurement unit or a numerical value. A sensor with an error correction function, comprising a memory chip having storage contents based on error information specific to the sensor, wherein the storage contents can be transmitted to the converter. When the sensor is connected to a power supply via itself or a converter, the stored content based on the error information in the memory chip is read and supplied to the converter immediately after power-on. The sensor according to claim 1, wherein: 3. The sensor according to claim 1, wherein the content stored in the memory chip comprises a correction value of a detection signal based on the error information.

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