JP2004246408A - Displacement sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a displacement sensor device which digitizes signal transmission between a head and a controller to suppress the effect of disturbance, suppresses signal attenuation even if an extension cable is used to connect between the head and the controller, and is excellent in displacement detection performance, extendability and convenience. <P>SOLUTION: The displacement sensor device comprises the head 2 having a sensor part 4 (displacement sensor) composed of a differential transformer with a coil L1 and a coil L2, and a movable core 4a, full-wave rectifiers 5a, 5b, a differential amplifier 6, an A/D conversion means 7, a matching data storage means 8, an amplitude adjusting part 9, a drive part 10 and a connector CN1; and the controller 3 having a data processing means 12, a power source 13 and a connector CN2. The head 2 and the controller 3 are connected with the extension cable 11 which is provided with a data bus BD and a memory bus BM, and has a connector CNx and a connector CNy at both ends. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a displacement sensor device for measuring a displacement of an object to be measured, for example, a warp or the like of a hard disk, and particularly, by digitally transmitting a displacement detection amount between a head and a controller, disturbances such as noise and the like and between the head and the controller. The present invention relates to a displacement sensor device that suppresses a change in a displacement detection amount due to an impedance of an extension cable to be connected.
[0002]
[Prior art]
FIG. 4 is a block diagram showing an example of a conventional displacement sensor device. In FIG. 4, a displacement sensor device 50 includes a sensor unit 53 using a differential transformer (coils L1 and L2) and a movable core 53a, a head 51 including a sensitivity adjustment unit 54, full-wave rectifiers 55a and 55b, It comprises an amplifier 56, an amplitude adjusting unit 57, a driving unit 58, and a controller 52 having a power supply 59.
[0003]
The head 51 and the controller 52 are directly connected via the connector CNa and the connector CNb, or are connected between the connector CNa and the connector CNb via an extension cable Cb having a connector CNc and a connector CNd.
[0004]
With the displacement of the measured object, the inductances of the coils L1 and L2 of the differential transformer simultaneously change in opposite (increase / decrease) directions with the movement of the core 53a of the sensor unit 53, and the AC sensor signals Sa and Sb change. Thus, the head 51 detects. In addition, by adjusting the sensitivity adjustment unit 54 of the head 51, the sensitivity of the sensor unit 53 is adjusted so that the sensor signal Sa and the sensor signal Sb are equal (Sa = Sb) when the measured object has no displacement. You.
[0005]
The controller 52 performs full-wave rectification on the sensor signals Sa and Sb supplied from the head 51 with full-wave rectifiers 55a and 55b, respectively, converts them into DC voltages, and inputs the converted DC voltages to a differential amplifier 56, A predetermined amplification process is performed to output a linear output corresponding to the displacement and a display output for external display.
[0006]
The amplitude adjuster 57 is controlled so that the DC voltage from the full-wave rectifier 55a is fed back, and a drive signal of the same level is always supplied to the sensor unit 53 via the drive unit 58 → the sensitivity adjuster 54. .
[0007]
As described above, in the conventional displacement sensor device 50, the signal transmission between the head 51 and the controller 52 is performed by the analog sensor signals Sa and Sb.
[0008]
Further, as disclosed in Patent Document 1, a conventional displacement sensor includes a sensor block including a light projecting unit, a light receiving optical system, a position detecting unit, and a correction value memory, a calculating unit, and a linearity correcting unit. A sensor block is connected to the sensor block by a connector. The sensor block converts the detected position signal (current signal) of the measured object into an analog voltage signal, and converts the converted analog voltage signal. Is transmitted to the controller block via the connector, and the controller block performs an operation based on the analog voltage signal supplied from the sensor block, calculates a distance measurement signal (measurement distance signal) LO of the measured object, and performs distance measurement. The linearity (linearity) of the signal (measurement distance signal) LO is corrected, and the distance signal L is output.
[0009]
The linearity correction means of the controller block performs A / D conversion on the distance measurement signal (measurement distance signal) LO calculated by the arithmetic means, and corrects the A / D converted digital distance measurement signal (measurement distance signal) and the sensor block. The CPU performs linearity correction processing based on the correction value data stored in the value memory, and performs D / A conversion on the corrected digital signal to obtain an analog distance signal L.
[0010]
With this configuration, the sensor block is provided with a correction value memory, and the linearity correction value data is supplied to the linearity correction means of the controller block, whereby the linearity of the distance measurement signal (measurement distance signal) LO is corrected and the distance signal L is corrected. Therefore, there is no need to make a one-to-one correspondence between the sensor block and the controller block, and an arbitrary sensor block can be connected to the controller block.
[0011]
[Patent Document 1]
Japanese Patent No. 2986023
[Problems to be solved by the invention]
The conventional displacement sensor device 50 shown in FIG. 4 and the conventional displacement sensor disclosed in Patent Document 1 perform signal transmission between a head 51 (or a sensor block) and a controller 52 (or a controller block). Since the analog signal is transmitted, if the analog signal is very small, it is susceptible to disturbances such as electric field noise and magnetic field noise, and the sensor signal (or position signal) is not transmitted accurately, resulting in an object to be measured. There is a problem that the displacement cannot be detected with high accuracy.
[0013]
In the conventional displacement sensor device 50 (or displacement sensor), the head 51 (or sensor block) and the controller 52 (or controller block) are connected to each other with an extension cable Cb to lengthen the displacement, and the displacement is measured. If a desired case occurs, an analog signal is transmitted between the head 51 (or the sensor block) and the controller 52 (or the controller block), so that the analog signal is attenuated due to the impedance of the extension cable Cb. However, there is a problem that the sensitivity of the displacement sensor device 50 (or the displacement sensor) changes and affects the displacement measurement.
[0014]
The present invention has been made to solve such a problem, and its object is to digitize signal transmission between the head and the controller to suppress the influence of disturbance and to connect the head and the controller with an extension cable. An object of the present invention is to provide a displacement sensor device which suppresses signal attenuation, is excellent in displacement detection performance, and is excellent in expandability and convenience.
[0015]
[Means for Solving the Problems]
In order to solve the above problems, a displacement sensor device according to the present invention processes a sensor signal from an optical sensor, a magnetic sensor, a displacement sensor such as a differential transformer, and a sensor from the displacement sensor, which outputs a sensor signal according to the displacement of a measurement object. A displacement sensor device comprising a head for supplying a displacement detection amount and a controller for measuring a displacement based on the displacement detection amount supplied from the head, wherein the head detects the displacement detection value by digital displacement detection data. A / D conversion means for supplying, and adaptation data storage means for storing adaptation data for adapting the displacement sensor to the controller, wherein the controller adapts the digital displacement detection data supplied from the A / D conversion means. Data processing means for performing correction and calibration processing based on the adaptation data supplied from the data storage means and measuring the data. Characterized in that connected between the controllers in connector having a data bus and a memory bus.
[0016]
In the displacement sensor device according to the present invention, the head includes A / D conversion means for supplying the displacement detection amount as digital displacement detection data, and adaptation data storage means for storing adaptation data for adapting the displacement sensor to the controller. The controller further comprises data processing means for performing correction and calibration processing on the digital displacement detection data supplied from the A / D conversion means based on the adaptation data supplied from the adaptation data storage means, and measuring the data. Since the head and the controller are connected by a connector having a data bus and a memory bus, the signal transmission between the head and the controller can be digitized to suppress the influence of disturbances. With excellent displacement detection performance and scalability by using a common controller. It is possible to realize improvement of convenience in beauty.
[0017]
Further, the displacement sensor device according to the present invention is characterized in that the head and the controller can be connected with an extension cable via a connector.
[0018]
In the displacement sensor device according to the present invention, since the head and the controller can be connected by the extension cable via the connector, even if the distance between the head and the controller is extended, it is not affected by the impedance of the extension cable. In addition, accurate displacement detection data can be transmitted.
[0019]
Furthermore, the adaptation data storage means according to the present invention is characterized in that it has an adaptation data storage area for storing adaptation data of sensitivity data, linear correction data, range data, calibration data and model data.
[0020]
Since the conformity data storage unit according to the present invention includes the conformity data storage area for storing the conformity data of the sensitivity data, the linear correction data, the range data, the calibration data, and the model data, the displacement detection data is corrected by the conformity data, The head can be adapted to the controller, and scalability of the controller to the head can be achieved.
[0021]
Further, the adaptation data storage means according to the present invention is characterized in that the adaptation data of the reference corresponding to the head is installed from an external reference device.
[0022]
Since the adaptation data storage means according to the present invention has installed the adaptation data of the reference corresponding to the head from an external reference device, there is no need to connect the head and the controller at the time of measuring the displacement and to make adjustments and settings, thereby improving work efficiency. can do.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram of a main part of an embodiment of a displacement sensor device according to the present invention. In this embodiment, a case where a differential transformer is used for a displacement sensor will be described.
[0024]
In FIG. 1, a displacement sensor device 1 includes a head 2 provided with a displacement sensor of a differential transformer (coils L1 and L2), and a controller 3 that measures the displacement of the measured object detected by the head 2.
[0025]
The head 2 includes a sensor unit 4 (displacement sensor) including a differential transformer of a coil L1 and a coil L2 and a movable core 4a, full-wave rectifiers 5a and 5b, a differential amplifier 6, an A / D converter 7, an adaptation data A storage unit 8, an amplitude adjustment unit 9, a drive unit 10, and a connector CN1 are provided.
[0026]
The sensor unit 4 forms a displacement sensor including a coil L1 and a coil L2 constituting a differential transformer and a movable core 4a, and displaces an object to be measured by moving the movable core 4a (vertical direction on the paper). An AC sensor signal generated by an AC drive signal supplied from the drive unit 10 by detecting and changing the inductances of the coils L1 and L2 of the differential transformer in directions opposite to each other as the movable core 4a moves. The balance between Sa and sensor signal Sb is lost, and sensor signal Sa and sensor signal Sb are input to full-wave rectifier 5a and full-wave rectifier 5b, respectively.
[0027]
When the measured object has no displacement or no measured object, the sensor signal Sa and the sensor signal Sb output from the sensor unit 4 are balanced, and the sensor signal Sa = the sensor signal Sb.
[0028]
The full-wave rectifier 5a and the full-wave rectifier 5b are each configured by a bridge circuit of a silicon diode, a Schottky barrier diode, and a switching element such as a transistor or an FET, and convert the AC sensor signal Sa and the sensor signal Sb supplied from the sensor unit 4. The DC voltage Va and the DC voltage Vb are supplied to the differential amplifier 6 by full-wave rectification and conversion into a DC voltage.
[0029]
The DC voltage Va is fed back from the full-wave rectifier 5a to the amplitude adjusting unit 9, and the amplitude adjusting unit 9 controls the AC driving signal supplied to the sensor unit 4 via the driving unit 10 so that the AC driving signal always has a constant value. I do.
[0030]
The differential amplifier 6 is composed of a plurality of operational amplifiers and the like, and amplifies a difference (Va−Vb) between the DC voltage Va supplied from the full-wave rectifier 5a and the DC voltage Vb supplied from the full-wave rectifier 5b. A DC displacement signal VK is provided to the A / D conversion means 7 as a displacement detection amount.
[0031]
The A / D conversion means 7 is composed of an A / D converter or the like, performs A / D conversion on the displacement signal VK provided from the differential amplifier 6 with a predetermined timing pulse, and displaces the digital displacement detection data DK. The detection amount is output to the connector CN1 via the data bus BD.
[0032]
The adaptation data storage means 8 is composed of a memory such as an EEPROM, stores various adaptation data DT for adapting the displacement sensor (head 2) to the controller 3, and stores the adaptation data DT via the memory bus BM into the connector CN1. Output to
[0033]
The memory area (conformance data storage area) of the conformity data storage means 8 stores sensitivity data DT1, linearity correction data DT2, range data DT3, calibration data DT4, and model data DT5. A part of the displacement detection data DK output from the A / D conversion means 7 is stored in the memory area (adaptive data storage area) of the adaptation data storage means 8 as the detection data DTO from the data processing means 12 of the controller 3. In some cases, the data is written via the bus BM.
[0034]
FIG. 2 is an image diagram of a suitable data storage area according to one embodiment of the suitable data storage means according to the present invention. In FIG. 2, the compatible data storage area stores (stores) a plurality of pieces of detection data DTO, sensitivity data DT1, linearity correction data DT2, range data DT3, calibration data DT4, and model data DT5 in each storage area. I do.
[0035]
Since the controller 3 is configured to execute correction appropriate for the head 2 based on the displacement detection data DK output from the A / D converter 7 and the adaptation data DT output from the adaptation data storage 8, 2 is adapted to the controller 3, and the controller 3 performs accurate data measurement irrespective of the type of the controller 3 only by performing data processing.
[0036]
As described above, the adaptation data storage unit 8 according to the present invention includes the adaptation data storage area for storing the adaptation data DT of the sensitivity data DT1, the linearity correction data DT2, the range data DT3, the calibration data DT4, and the model data DT5. The head 2 can be adapted to the controller 3 by correcting the displacement detection data DK with the adaptation data DT, and expandability of the controller 3 with respect to the head 2 can be realized.
[0037]
Further, the adaptation data storage means 8 stores the adaptation data DT of the standard corresponding to each head 2, but is required beforehand from the external standard device 14 to the head 2 before connecting the head 2 and the controller 3. Install and set the ideal standard conformity data DT.
[0038]
Since the adaptation data storage means 8 installs the reference adaptation data DT, there is no need to connect the head 2 and the controller 3 and make any adjustments or settings. Measurement efficiency can be improved.
[0039]
As described above, since the adaptation data storage means 8 according to the present invention installs the adaptation data DT of the reference corresponding to the head 2 from the external reference device 14, the head 2 and the controller 3 are connected at the time of displacement measurement to perform adjustment and adjustment. There is no need for setting, and work efficiency can be improved.
[0040]
The controller 3 includes a data processing unit 12, a power supply 13, and a connector CN2, and receives the displacement detection data DK transmitted from the A / D conversion unit 7 of the head 2 and the adaptation data DT transmitted from the adaptation data storage unit 8. It receives and corrects the displacement detection data DK with the adaptation data DT to display the displacement amount, or outputs a linear output VO1 and a display output VO2 to the outside.
[0041]
FIG. 3 is a block diagram of a main part of an embodiment of the data processing means according to the present invention. In FIG. 3, a data processing means 12 is composed of various arithmetic means, processing means, memory and the like based on a microprocessor, and includes a control means 15, an arithmetic means 16, a storage means 17, a range determination means 18, a D / A conversion means. 19, a display driving means 20, and a display 21.
[0042]
The control unit 15 controls the operation of the data processing unit 12 by controlling the calculation unit 16, the storage unit 17, the range determination unit 18, and the D / A conversion unit 19.
[0043]
The control means 15 takes in the displacement detection data DK transmitted from the head 2 via the data bus BD and the adaptation data DT transmitted via the memory bus BM, and controls the operation means 16 to control the displacement detection data DK. Then, the displacement detection data DK is corrected based on the matching data DT, and the corrected displacement detection data is temporarily stored in the storage unit 17. The corrected displacement detection data includes linearity correction including sensitivity correction and offset correction, tilt calibration, model data of the displacement sensor (head 2), and the like.
[0044]
Further, the control unit 15 reads out the corrected displacement detection data temporarily stored in the storage unit 17, provides the corrected displacement detection data to the range determination unit 18, and executes the range determination of the corrected displacement detection data.
[0045]
Further, the control means 15 supplies the corrected displacement detection data to the D / A conversion means 19, and executes control for converting the digital corrected displacement detection data into analog corrected displacement detection data.
[0046]
The storage unit 17 temporarily stores the displacement detection data DK, the adaptation data DT, and the corrected displacement detection data calculated by the calculation unit 16 under the control of the control unit 15, and supplies the stored data to the control unit 15. Note that the matching data DT to be stored includes sensitivity data DT1, linearity correction data DT2, range data DT3, calibration data DT4, and model data DT5.
[0047]
The range determination means 18 determines the corrected displacement detection data by comparing it with the range data DT3, and turns on an LED or sounds a buzzer depending on whether the corrected displacement detection data is within the range of the range data DT3. .
[0048]
The D / A conversion means 19 is constituted by a D / A converter, performs D / A conversion on digital corrected displacement detection data, outputs analog corrected displacement detection data, and outputs a linear output VO1 to the outside. , To the display driving means 20.
[0049]
The display drive means 20 uses the linear output VO1 supplied from the D / A conversion means 19 as a drive signal (display signal), displays the display signal on a display 21 such as an LCD (liquid crystal), and externally outputs a display output VO2. Supply.
[0050]
That is, the data processing unit 12 converts the displacement detection data DK transmitted from the head 2 into the sensitivity correction, the linearity correction (including the offset correction), the measurement range determination, the inclination calibration, the display of the model of the displacement sensor, and the like based on the adaptation data DT. Is performed, and the displacement of the measured object detected by the head 2 is measured and displayed with high accuracy.
[0051]
It should be noted that the data processing means 12 does not need to have the performance paired with the head 2, and may include the general processing means shown in FIG. 3 and can be shared as the controller 3.
[0052]
Returning to FIG. 1, the connection between the head 2 and the controller 3 is made by a connector CN1 (head 2) having a data bus BD and a memory bus BM and a connector CN2 (controller 3).
[0053]
Since the signal transmission between the head 2 and the controller 3 is digitized, the influence of disturbances such as electric field noise and magnetic field noise can be suppressed, and the displacement detection performance can be improved.
[0054]
Further, in the case of measuring the displacement where the distance between the head 2 and the controller 3 is long, the head 2 and the controller 3 are extended by providing a data bus BD and a memory bus BM, and having a connector CNx and a connector CNy at both ends. Connect with cable 11.
[0055]
Since the head 2 and the controller 3 are connected by using the extension cable 11 having the data bus BD and the memory bus BM to perform digitized signal transmission, the influence of the cable impedance and the disturbance such as electric field noise and magnetic field noise can be reduced. Accurate displacement detection data can be transmitted with less influence.
[0056]
Although the present embodiment has been described with respect to a case where a differential transformer is used as a displacement sensor, the present invention can be similarly applied to a displacement sensor using an optical sensor or a magnetic sensor.
[0057]
【The invention's effect】
As described above, in the displacement sensor device according to the present invention, the head stores A / D conversion means for supplying the displacement detection amount as digital displacement detection data, and adaptation data for adapting the displacement sensor to the controller. The controller performs correction and calibration processing of the digital displacement detection data supplied from the A / D converter based on the conformity data supplied from the conformance data storage, and measures the digital displacement detection data. Since the head and the controller are connected by a connector having a data bus and a memory bus, the signal transmission between the head and the controller can be digitized to suppress the influence of disturbance, and the controller has a data processing means. Regardless of the type, it can be adapted to the head, and has excellent displacement detection performance. It is possible to achieve an improvement in expandability and convenience are working to reduction.
[0058]
Further, in the displacement sensor device according to the present invention, since the connection between the head and the controller can be made by an extension cable via the connector, even if the distance between the head and the controller is extended, the influence of the impedance of the extension cable is reduced. Accurate displacement detection data can be transmitted without receiving it.
[0059]
Furthermore, the adaptation data storage means according to the present invention includes an adaptation data storage area for storing adaptation data of sensitivity data, linear correction data, range data, calibration data, and model data, so that the displacement detection data is corrected by the adaptation data. However, the head can be adapted to the controller, and the expandability of the controller with respect to the head can be realized.
[0060]
In addition, since the adaptation data storage means according to the present invention installs the adaptation data of the reference corresponding to the head from an external reference device, there is no need to connect the head and the controller at the time of displacement measurement and to make adjustments and settings. Can be up.
[Brief description of the drawings]
FIG. 1 is a block diagram of a main part of one embodiment of a displacement sensor device according to the present invention; FIG. 2 is an image diagram of a suitable data storage area according to one embodiment of a suitable data storage means according to the present invention; FIG. FIG. 4 is a block diagram showing an example of a conventional displacement sensor device.
REFERENCE SIGNS LIST 1 displacement sensor device 2 head 3 controller 4 sensor unit 4a movable cores 5a, 5b full-wave rectifier 6 differential amplifier 7 A / D converter 8 compatible data storage unit 9 amplitude adjustment unit 10 drive unit 11 extension cable 12 data processing unit 13 Power supply 14 Standard unit 15 Control unit 16 Operation unit 17 Storage unit 18 Range determination unit 19 D / A conversion unit 20 Display drive unit 21 Display BD Data bus BM Memory bus L1, L2 Coil Sa, Sb Sensor signal VK Displacement signal DK Displacement Detection data DT Compatible data CN1, CN2, CNx, CNy Connector VO1 Linear output VO2 Display output

Claims (4)

An optical sensor that outputs a sensor signal in accordance with the displacement of the measurement object, a magnetic sensor, a displacement sensor such as a differential transformer, a head that processes a sensor signal from the displacement sensor and supplies a displacement detection amount, A controller for measuring the displacement based on the supplied displacement detection amount, a displacement sensor device,
The head includes: A / D conversion means for supplying a displacement detection amount as digital displacement detection data; and adaptation data storage means for storing adaptation data for adapting the displacement sensor to the controller.
The controller includes a data processing unit that performs correction and calibration processing on the digital displacement detection data supplied from the A / D conversion unit based on the adaptation data supplied from the adaptation data storage unit and measures the data.
A displacement sensor device wherein the head and the controller can be connected by a connector having a data bus and a memory bus. The displacement sensor device according to claim 1, wherein the displacement sensor device connects the head and the controller with an extension cable via the connector. 2. The displacement sensor device according to claim 1, wherein the adaptation data storage unit includes an adaptation data storage area for storing adaptation data of sensitivity data, linear correction data, range data, calibration data, and model data. 4. The displacement sensor device according to claim 3, wherein the adaptation data storage unit installs adaptation data of a reference corresponding to the head from an external reference device.

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