Level meter

Abstract

To provide a level meter capable of correctly measuring a level of an object to be stored in a container.SOLUTION: A level meter includes a distribution determination part, an extraction part, a candidate determination part, and a display part. The distribution determination part determines a reception intensity distribution of a reflection signal with respect to a distance from the level meter, based on the reception intensity of the reflection signal by a measurement signal being reflected. The candidate determination part extracts a plurality of combinations of a peak position and peak intensity from the reception intensity distribution by the extraction part, and determines them as a plurality of peak candidates. The display part displays a measurement value corresponding to each of the plurality of peak candidates, and candidate confirmation screens 822a, 822b, 822c, 822d, 822e including a reception intensity scale 890 regarding reception intensity.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The present invention relates to a level meter for measuring the level of a contained object. [Background technology]

[0002] In containers that store fluid substances such as liquids, powders, and granules, level meters are sometimes used to measure the height of the interface of the substance, that is, the level (liquid surface level, powder top surface level, etc.). The level meter described in Patent Document 1 is equipped with a probe to which a pulse signal is input, and measures the level based on the pulse input to the probe and the pulse reflected by the object to be measured. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-002091 A Summary of the Invention [Problem to be solved by the invention]

[0004] Depending on the type of level meter, a signal such as an electric wave may be transmitted from the level meter to the contents in the container to measure the level of the contents without using a probe. The level meter can measure the level based on the transmitted signal and the signal reflected at the interface of the contents.

[0005] However, there may be elements inside the container that reflect signals other than the interface of the contents. For example, if the container is provided with an agitator for agitating the contents, the agitator may reflect the signal. If the container is, for example, a large tank, a ladder may be provided so that workers can work inside the tank. The ladder inside the tank may also reflect the signal. Also, if the contents are a material that easily transmits signals (such as oil), the signal may pass through the contents and be reflected at the bottom of the container.

[0006] If there are elements that reflect signals other than the interfaces of the contained items, the level meter cannot correctly measure the level of the contained items unless it can distinguish between signals reflected by the interfaces of the contained items and other signals.

[0007] In view of the above problems, an object of the present invention is to provide a level meter capable of accurately measuring the level of an object contained in a container. [Means for solving the problem]

[0008] In order to solve the above problem, a level meter as an example of an embodiment of the present invention is a level meter that measures the level of contents contained in a container, and includes a transceiver unit that includes a transmission circuit that transmits a measurement signal for measuring the level and a receiving circuit that receives a reflected signal resulting from the reflection of the measurement signal, a distribution determination unit that determines a reception intensity distribution of the reflected signal versus distance from the level meter based on the reception intensity of the reflected signal received by the receiving circuit, an extraction unit that extracts a peak position and a peak intensity from the reception intensity distribution determined by the distribution determination unit, a measurement value determination unit that determines a measurement value related to the distance or level of the contents based on the peak position extracted by the extraction unit, a candidate determination unit that extracts multiple combinations of peak positions and peak intensities by the extraction unit from the reception intensity distribution determined by the distribution determination unit and determines them as multiple peak candidates, and a display unit that displays information related to the measurement values ​​and reception intensities corresponding to each of the multiple peak candidates determined by the candidate determination unit. Effect of the Invention

[0009] According to the present invention, a plurality of peak candidates extracted from the reception intensity distribution of the reflected signal are displayed on the display unit. These peak candidates include a peak corresponding to the level of the contents and a peak corresponding to an element other than the contents. By selecting the peak corresponding to the level of the contents from the peak candidates, the level meter can distinguish between a signal reflected at the interface of the contents and other signals and measure the level correctly. Furthermore, the level meter can optimally set the measurement conditions necessary to determine a measurement value related to the level of the contents based on the reception intensity distribution and the peak corresponding to the level of the contents. By optimally setting the measurement conditions, the level meter can maintain a state in which the level is measured correctly. [Brief description of the drawings]

[0010] [Figure 1] FIG. [Diagram 2] Cross-sectional view of a level meter. [Diagram 3] FIG. 2 is a diagram showing a state in which a level gauge is attached to a container that contains an object. [Figure 4] FIG. 2 is a block diagram illustrating an example of the relationship between components of a level meter. [Diagram 5] FIG. 2 is a diagram showing an example of the configuration of a radar control unit and a transmitting / receiving unit. [Figure 6] FIG. 4 is a diagram showing the relationship between a measurement signal and a reflected signal. [Figure 7] 11 is a graph showing a reception intensity distribution when multiple peaks occur. [Figure 8] FIG. 4 is a diagram showing state transitions of a level meter. [Figure 9] FIG. [Figure 10] FIG. 4 is a diagram showing state transitions of the level meter in the adjustment function. [Figure 11] FIG. 11 is a flowchart showing a process flow in an optimization mode. [Figure 12] FIG. 11 is a diagram illustrating setting contents according to a diagnosis result. [Figure 13] FIG. 11 is a flowchart showing a process flow in a limited mode. [Figure 14] FIG. 13 is a diagram showing an adjustment mode selection screen. [Figure 15] FIG. [Figure 16] FIG. 13 is a diagram showing a candidate selection message. [Figure 17] FIG. [Figure 18] FIG. 13 is a diagram showing a suggested message when the influence of surrounding signals is large. [Figure 19] FIG. 13 is a diagram showing a screen for confirming the calculation result of a short-distance measurement limit. [Figure 20] 13A and 13B are diagrams showing suggestion messages when the calculation result of the short-distance measurement limit is undesirable. [Figure 21] FIG. 13 is a diagram showing a confirmation screen for starting optimization processing. [Figure 22] FIG. [Figure 23] FIG. 13 is a diagram showing a display screen showing whether or not learning has been performed. [Figure 24] FIG. 13 is a diagram showing a confirmation screen for asking whether or not the learning execution result needs to be deleted. [Diagram 25] FIG. 13 is a diagram showing a learning execution confirmation screen. [Figure 26] FIG. 13 is a diagram showing a numeric input screen relating to distance. [Figure 27] FIG. 13 is a diagram showing a learning completion screen. [Figure 28] FIG. 11 is a perspective view showing another example of a level meter. [Figure 29] FIG. 13 is a diagram showing another example of the current value display screen. [Diagram 30] FIG. 13 is a diagram showing another example of the candidate confirmation screen. [Diagram 31] FIG. 13 is a diagram showing another example of the optimization completion screen. [Diagram 32] FIG. 11 is a perspective view showing still another example of a level meter. [Diagram 33] 6A to 6C are diagrams showing screen transitions on the display unit of the remote control device in the adjustment function. [Diagram 34] 11A to 11C are diagrams showing screen transitions on the display unit of the remote control device in the limited mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference symbols, and basically the description will not be repeated. In the following description, terms meaning positions or directions such as front, back, left, right, up, and down may be used, but these terms are used for convenience to facilitate understanding of the embodiment. Unless otherwise clearly stated, these terms are not limited to front, back, left, right, up, and down in the strict geometric sense.

[0012] Hereinafter, a level meter 10 as an example of an embodiment of the present invention will be described with reference to the drawings. First, an example of the structure and usage state of the level meter 10 will be described with reference to Figs. 1, 2, and 3. Fig. 1 shows a perspective view of the level meter 10 of this embodiment. Fig. 2 shows a cross-sectional view of the level meter 10 of Fig. 1. Fig. 3 shows a state in which the level meter 10 is attached to a container 70 (e.g., a tank) that contains an item 72.

[0013] The level meter 10 is a device that measures the level Y of the contained object 72 (e.g., liquid, powder, granules, etc.) that is the measurement target. The level Y to be measured is the height of the interface 74 of the contained object 72 in the container 70. A specific example of the level Y is the distance from the bottom of the container 70 to the liquid surface of the liquid contained in the container 70. A measurement axis is set in the level meter 10, and the level meter 10 measures the level Y along the measurement axis.

[0014] As an example of a usage state of the level meter 10, a container 70 in FIG. 3 contains a liquid (water, oil, chemical liquid, etc.) that becomes the contents 72 in a liquid treatment facility. For example, when the contents 72 in the container 70 are supplied to a liquid treatment process, the level Y of the contents 72 in the container 70 decreases. Also, when the contents 72 are replenished to the container 70, the level Y of the contents 72 in the container 70 increases. For example, a water inlet 75 is provided on the outer wall (upper wall in FIG. 3) of the container 70. A water inlet pipe 76 is fluidly connected to the container 70 through the water inlet 75. The water inlet pipe 76 is connected to a water inlet device 78 (e.g., a device including a pump, a valve, etc.) provided outside the container 70. The water inlet device 78 is a device that supplies (injects) the contents 72 into the container 70 from outside the container 70. The water inlet device 78 adjusts the amount of water to be poured into the container 70 according to the level Y of the contents 72 in the container 70. The water injection device 78 also stops pouring water depending on the level Y of the contents 72 in the container 70. The water injection device 78 controls the replenishment of the contents 72 to the container 70 depending on the level Y of the contents 72 in the container 70, which decreases as the contents 72 is consumed by, for example, a liquid treatment process, so that the level Y of the contents 72 in the container 70 is within a predetermined range.

[0015] The level meter 10 in FIG. 1 has a generally cylindrical shape extending in the longitudinal direction A (direction of the measurement axis). The level meter 10 has a housing 15 and a sensor unit 16, and the housing 15 and the sensor unit 16 are arranged along the longitudinal direction A. The sensor unit 16 is disposed at one end side (lower side in FIG. 1) of the level meter 10 in the longitudinal direction A, and the housing 15 is disposed at the other end side (upper side in FIG. 1) in the longitudinal direction A. Hereinafter, one end (lower end) of the sensor unit 16 in the longitudinal direction A is referred to as a measurement end 40. As shown in FIG. 2, a dielectric lens 48 is disposed at the measurement end 40. Hereinafter, one end side of the level meter 10 in the longitudinal direction A may be referred to as the lower side, and the other end side in the longitudinal direction A may be referred to as the upper side.

[0016] 3, the level meter 10 in Fig. 1 measures the level Y of the contained item 72 with the measuring end 40 facing the contained item 72. For example, when the level meter 10 measures the height of the liquid surface (interface 74) of the liquid, the longitudinal direction A of the level meter 10 is oriented in the same direction as the change in the height of the liquid surface, i.e., the vertical direction (height direction, gravity direction).

[0017] The level meter 10 in FIG. 3 transmits radio waves serving as a measurement signal Tx from the measurement end 40 toward the contained object 72. Then, a reflected signal Rx resulting from the measurement signal Tx being reflected by an interface 74 of the contained object 72 is received by the measurement end 40. The level meter 10 calculates the level Y of the contained object 72 based on the measurement signal Tx and the reflected signal Rx. For example, when performing measurement using a Time of Flight (ToF) method, the level meter 10 calculates a distance YA from the measurement end 40 to the interface 74 based on the difference between the measurement signal Tx and the reflected signal Rx, and calculates the level Y based on the distance YA. Also, for example, when performing measurement using a radar method using a Frequency Modulated Continuous Wave (FMCW), the level meter 10 calculates a distance YA from the measurement end 40 to the interface 74 based on the frequency of a waveform obtained by mixing the measurement signal Tx and the reflected signal Rx, and calculates the level Y based on the distance YA.

[0018] As shown in FIG. 1, the sensor unit 16 has a mounting screw portion 18 with a thread engraved on the surface of a cylinder, above the measurement end 40. Furthermore, a mounting portion 17 with a diameter larger than that of the mounting screw portion 18 is provided above the mounting screw portion 18. The mounting portion 17 in FIG. 1 has a nut-like shape. Note that the mounting portion 17 may have any structure that allows the level gauge 10 to be mounted to an object (such as a container 70 that contains liquid), and is not limited to a nut-like shape. For example, the mounting portion 17 may have a cylindrical shape with a non-slip protrusion. The non-slip protrusion of the mounting portion 17 serves as a non-slip protrusion when the level gauge 10 is mounted or removed (rotational attachment / detachment) while rotating around the longitudinal direction A relative to the object. In addition, instead of the mounting portion 17 and the mounting screw portion 18, a mounting flange for mounting the level gauge 10 to the object may be formed. In addition, even when a mounting flange is formed, the mounting portion 17 and the mounting screw portion 18 may be provided in addition to the mounting flange.

[0019] The level gauge 10 in FIG. 3 is attached to the upper side of the container 70. An attachment hole 71 is provided on the upper side of the container 70. The attachment hole 71 is a screw hole, and the level gauge 10 is attached to the container 70 by screwing the attachment screw portion 18 of the level gauge 10 into the attachment hole 71. For example, a user of the level gauge 10 can screw the attachment screw portion 18 into the attachment hole 71 by rotating the nut-shaped attachment portion 17 with the tip of the attachment screw portion 18 aligned with the attachment hole 71. Note that the structure for attaching the level gauge 10 to the container 70 is not limited to this. For example, the attachment hole 71 may not have a thread, and a separate nut may be screwed into the attachment screw portion 18 exposed inside the container 70, thereby attaching the level gauge 10 to the container 70. Also, the top surface of the container 70 may be open, and the level gauge 10 may be attached to a mounting fixture provided above the container 70 using a nut and the attachment screw portion 18. Furthermore, the method of attaching the level meter 10 to the container 70 is not limited to screwing using the mounting thread portion 18, and threads do not have to be formed on the outer circumferential surface of the sensor portion 16. For example, the level meter 10 may be attached to the container 70 by providing a flange on either or both of the level meter 10 and the container 70 and fastening the flange to the level meter 10 or the container 70 with a bolt.

[0020] The display unit 20 is provided on the housing 15 arranged above the sensor unit 16. The display unit 20 is arranged on the outer peripheral surface of the housing 15 that extends along the longitudinal direction A. The display unit 20 preferably includes an active matrix display device (active matrix display) capable of displaying various information. For example, the display unit 20 includes an LCD (Liquid Crystal Display). In particular, the display unit 20 preferably includes an LCD capable of color display (display in multiple colors).

[0021] The display unit 20 may also be a two-line reflective color liquid crystal display that transmits and receives power and communicates data using two power lines. A two-line display communicates data by varying the magnitude of the current that travels through the power lines. For example, the current consumption of the power lines varies in the range of 4-20 mA. The content of the data being transmitted and received is represented by the magnitude of this current consumption. A reflective display allows a user to view the displayed content by external light reflected on its surface. A two-line display requires a small amount of power to be used, but a two-line reflective color liquid crystal display can display a variety of information with a small amount of power consumption.

[0022] The display unit 20 displays the level Y of the contained items 72 measured by the sensor unit 16. In Figs. 1 and 3, a bar display 22 whose length expands or contracts according to the value of the level Y is displayed on the display unit 20. The display unit 20 also displays a color gauge 24 (one example of a gauge) that is colored in multiple colors. The length direction of the color gauge 24 is arranged along the expansion and contraction direction of the bar display 22. The color gauge 24 includes multiple sections (three in Fig. 1) that are arranged along the expansion and contraction direction of the bar display 22. The sections of the color gauge 24 correspond to multiple level ranges set for the level Y of the contained items 72, and the level ranges are defined by multiple level setting values ​​(e.g., threshold values) set for the level Y.

[0023] Display unit 20 displays the relative position of level Y with respect to container 70 that contains contents 72, together with bar display 22. Specifically, the length of bar display 22 expands or contracts according to the value of level Y of contents 72 within container icon 25 that resembles container 70. The length of bar display 22 with respect to the size of container icon 25 corresponds to the relative position of level Y of contents 72 with respect to the entire container 70.

[0024] A bar arrow 22a is displayed at the tip (top end) of the extension / contraction direction of the bar display 22. The bar arrow 22a indicates a position within the color gauge 24 that corresponds to the length of the bar display 22. The color gauge 24 indicates to which level range the measured level Y belongs, among a plurality of level ranges defined by level setting values.

[0025] The color gauge 24 includes a plurality of sections. The plurality of sections of the color gauge 24 are divided into a plurality of level ranges. The plurality of sections of the color gauge 24 are arranged along the direction of increase and decrease of the level Y on the display unit 20. The container icon 25 and the bar display 22 are displayed next to the color gauge 24 (alongside the color gauge 24). Since the color gauge 24 is displayed along with the container icon 25 and the bar display 22 on the display unit 20, the relative position of the level setting value with respect to the container 70 is displayed together with the bar display 22.

[0026] The display unit 20 also displays an auxiliary display unit 26 that shows information other than the bar display 22 and the color gauge 24. In Fig. 1, the measured level Y is displayed in a numerical value (mm, millimeter value) on the auxiliary display unit 26.

[0027] The display unit 20 also displays an output status display section 27. The output status display section 27 displays the status of a signal line whose output changes depending on the relationship between the measured level Y and the level setting value. For example, if a signal is sent from a specific signal line when the level Y exceeds a threshold value set as the level setting value, a number corresponding to that signal line is displayed on the output status display section 27. For example, in FIG. 1, the bar arrow 22a indicates the topmost section of the three sections of the color gauge 24. This state of the display unit 20 indicates that two threshold values ​​are set as the level setting value and that the measured level Y exceeds both of the two threshold values.

[0028] If a signal line is provided that outputs a signal when the measured level Y exceeds a threshold value, a signal is output from each of the two signal lines corresponding to the two threshold values ​​in the state shown in Fig. 1. In order to indicate that signals are being output from two signal lines in Fig. 1, numbers corresponding to the two signal lines that are outputting signals (here, "1" and "2") are displayed in output status display section 27.

[0029] In addition, an operation unit 30 is also arranged on the same outer surface of the housing 15 as the display unit 20. The operation unit 30 in Fig. 1 is arranged adjacent to the display unit 20, and includes a menu key 32 and a direction key 33 arranged along the longitudinal direction A. The direction key 33 also has an up key 36 and a down key 35 arranged along the longitudinal direction A.

[0030] A connection part 12 is provided on the upper side of the housing 15. The connection part 12 in FIG. 1 is cylindrical and extends in the longitudinal direction A. The outer peripheral surface of the cylindrical connection part 12 is a connection screw part 14 with threads. As shown in FIG. 2, an external input terminal 12C and an external output terminal 12D are included inside the connection part 12. The external input terminal 12C is a terminal for inputting a signal or power, or both, from the outside to the level meter 10. The external output terminal 12D is a terminal for outputting a signal from the level meter 10 to the outside. The external input terminal 12C and the external output terminal 12D may each include multiple signal lines or multiple terminals. For example, a signal may be output to the outside from different signal lines or different output terminals depending on the level range to which the measured level Y belongs.

[0031] A connection cable 92 shown in Fig. 3 is connected to the connection unit 12. The connection cable 92 connects the level meter 10 to a management device 90 (such as a programmable controller) provided outside the container 70. A signal indicating the level Y of the contained item 72 measured by the level meter 10 is transmitted (output) to the management device 90 via an external output terminal 12D (part of an output unit 66 described below) of the connection unit 12 and the connection cable 92. The management device 90 manages the operation of the entire facility including the container 70 based on the signal received from the level meter 10.

[0032] In addition, a status light 52 is provided between the connection part 12 and the display part 20 so as to surround the lower side (base) of the connection part 12. The lighting state of the status light 52 changes according to the measured level Y of the object. The user can roughly know the state of the object by visually checking the lighting state of the status light 52. The status light 52 can emit light in various lighting colors (e.g., green, yellow, red, etc.). It is preferable that the status light 52 emits light in a lighting color corresponding to the level range to which the level Y measured by the level meter 10 belongs. For example, it is preferable that the status light 52 emits light in the same color as the color of the section indicated by the bar arrow 22a of the color gauge 24, which is color-coded by a plurality of colors for each section.

[0033] 2, a sensor IC 41 (IC: Integrated Circuit) and a sensor board 42 supporting the sensor IC 41 are disposed inside the sensor unit 16. The sensor IC 41 transmits and receives radio waves and processes signals to measure the level Y of the contained item 72. The signal processed by the sensor IC 41 is transmitted to a display board 60 provided in the terminal unit 21.

[0034] For example, a monolithic microwave integrated circuit (MMIC) is used as the sensor IC 41. The MMIC is an IC in which a plurality of semiconductor components that transmit and receive radio waves, and perform signal processing based on the transmitted and received radio waves are integrated into a single semiconductor device (one chip). In the sensor IC 41 in FIG. 2, an antenna is integrated into the MMIC using antenna in package (AiP) technology or antenna on package (AoP) technology. That is, in FIG. 2, the sensor IC 41 is an antenna-integrated package (antenna on package) in which a transmitting circuit 43T that transmits radio waves and a receiving circuit 43R that receives radio waves are integrated into a single semiconductor device. By using an antenna-integrated MMIC as the sensor IC 41, the volume occupied by the configuration for transmitting and receiving radio waves is reduced, and the overall dimensions of the level meter 10 are made compact. The sensor IC 41 is not limited to a single antenna-integrated MMIC, and may include a plurality of ICs. The sensor IC 41 may include, for example, an MMIC and a microcomputer. The antenna-integrated MMIC may include a radio wave transmitting antenna, a radio wave receiving antenna, and a circuit that controls the transmission and reception of radio waves, and the microcomputer may include a circuit that performs signal processing and arithmetic processing based on a signal received from the antenna-integrated MMIC.

[0035] The sensor IC 41 is mounted on the lower surface of the sensor board 42. The sensor board 42 is an electronic circuit board in which various electronic circuit elements are arranged on a plate made of an insulator such as glass or resin. In Fig. 2, the sensor board 42 is arranged so as to be oriented perpendicular to the longitudinal direction A (horizontal direction in Fig. 2).

[0036] The measurement end 40 is located below the sensor substrate 42. The measurement end 40 in FIG. 2 includes, as an internal structure, a waveguide 45, a horn antenna 46, and a dielectric lens 48. When the sensor IC 41 is an antenna-integrated MMIC, a radio wave serving as a measurement signal Tx is transmitted from a transmission circuit 43T of the sensor IC 41. The measurement signal Tx transmitted from the sensor IC 41 is guided toward the contained object 72 through the waveguide 45, the horn antenna 46, and the dielectric lens 48 in this order. The reflected signal Rx reflected by the contained object 72 and incident on the measurement end 40 is guided toward the receiving circuit 43R of the sensor IC 41 through the dielectric lens 48, the horn antenna 46, and the waveguide 45 in this order.

[0037] The waveguide 45, the horn antenna 46, and the dielectric lens 48 arranged inside the sensor unit 16 guide radio waves in the longitudinal direction A by their respective directivities for radio waves, and when combined, they show strong directivity for radio waves as a whole. Therefore, even if the sensor unit 16 has a small longitudinal dimension (length along the longitudinal direction A), it can properly guide the measurement signal Tx and the reflected signal Rx. Furthermore, because the measurement signal Tx and the reflected signal Rx are properly guided, the measurement signal Tx can be transmitted and the reflected signal Rx can be received by the common measurement end 40, even if the position of the transmitting circuit 43T and the position of the receiving circuit 43R are different in the sensor IC 41. Therefore, by using the waveguide 45, the horn antenna 46, and the dielectric lens 48, the designer of the level meter 10 can reduce the longitudinal dimension of the level meter 10 including the sensor unit 16, and the overall dimension of the level meter 10 can be made compact.

[0038] Meanwhile, inside the housing 15, a rotation mechanism 19 is provided on the upper side of the sensor board 42. The rotation mechanism 19 in FIG. 2 is disposed at the lower end (one end in the longitudinal direction A) of the housing 15, that is, between the housing 15 and the sensor unit 16. The rotation mechanism 19 can rotate the housing 15 relative to the sensor unit 16. The rotation mechanism 19 is disposed so that the rotation axis is parallel to the longitudinal direction A. By providing the rotation mechanism 19, the user can rotate the housing 15 to orient the display unit 20 in a direction that is easy to view. In particular, when the level gauge 10 is attached to a container 70 (such as a tank) containing the contents 72 by the mounting screw portion 18, the user can orient the display unit 20 in a direction that is easy to view without moving the entire level gauge 10.

[0039] A display board 60 is disposed inside the housing 15 above the rotation mechanism 19. The display board 60 is an electronic circuit board in which various electronic circuit elements are disposed on a plate made of an insulating material such as glass or resin. A signal processing circuit for controlling the display unit 20 is mounted on the display board 60. The display board 60 receives a signal from the sensor IC 41 and converts the level Y of the contained item 72 measured by the sensor unit 16 into a signal for display on the display unit 20. The display board 60 in FIG. 2 is disposed on the back side of the display unit 20 (inside the housing 15 in FIG. 2).

[0040] 2 includes a display device 28 and a transparent display window 29. The display device 28 is, for example, an LCD, particularly an LCD capable of color display. The display window 29 is a plate made of an optically transparent material such as glass, acrylic, polyarylate, or polycarbonate, and optically transmits the display content of the display device 28 to the outside of the housing 15.

[0041] The status light 52 arranged between the display unit 20 and the connection unit 12 includes a plurality of status LEDs 50 (LED: Light Emitting Diode) and a transparent window 53. The plurality of status LEDs 50 are arranged above the display board 60 and the display unit 20. The lighting state of the status LEDs 50 changes according to the level of the object measured by the sensor unit 16. In addition, a transparent window 53 including a member that diffuses light (such as a light diffusion film) is arranged above the status LEDs 50. The light emitted from the status LEDs 50 is guided to the outside of the housing 15 through the transparent window 53. Therefore, as the lighting state of the status LEDs 50 changes according to the level Y of the object, the lighting state of the status light 52 changes. In addition, since the transparent window 53 includes a member that diffuses light, the light emitted from the status LEDs 50 is diffused uniformly in all directions around the connection unit 12.

[0042] The lighting state of the status LED 50 changes according to the level Y of the contained contents 72 measured by the sensor unit 16. The light emitted from the status LED 50 is guided to the outside of the housing 15 through the transparent window 53. Therefore, as the lighting state of the status LED 50 changes according to the level Y of the contained contents 72, the lighting state of the status lamp 52 changes. In addition, since the transparent window 53 includes a material that diffuses light, the light emitted from the status LED 50 is diffused in a direction intersecting with the longitudinal direction A. Therefore, the user can easily visually grasp the lighting state of the status lamp 52 from a long distance.

[0043] The status LED 50 may emit light in a single color (e.g., red, yellow, green, etc.) or may emit light by switching between multiple colors (e.g., red, yellow, green, etc.). When the status LED 50 emits light by switching between multiple colors, multiple light-emitting elements that emit light in different colors may be included in one LED, or a combination of multiple LEDs that emit light in different colors may be arranged as the status LED 50. The status LED 50 may emit light by mixing multiple colors. When the status LED 50 emits light by switching between multiple colors, the status LED 50 may emit light in a color corresponding to the color of the section of the color gauge 24 that corresponds to the level range to which the measured level Y belongs.

[0044] Next, the relationship between the components of the level meter 10 will be described with reference to FIG. 4. FIG. 4 is a block diagram that shows an example of the relationship between the components of the level meter 10. As shown in FIG. 4, the sensor IC 41 of the sensor unit 16 includes a transmitting / receiving unit 43, a radar control unit 44, and a processing unit 62. The transmitting / receiving unit 43 has a transmitting circuit 43T that transmits a measurement signal Tx and a receiving circuit 43R that receives a reflected signal Rx. The sensor IC 41 may include multiple ICs. For example, the sensor IC 41 may include an antenna-integrated MMIC and a microcomputer.

[0045] The radar control unit 44 has a transmission control unit 80 that determines the waveform of the measurement signal Tx, a radar transmission and reception circuit 81 that performs mutual conversion between digital signals and radio waves, and a signal processing unit 89 that performs signal processing based on the measurement signal Tx and the reflected signal Rx. When the sensor IC 41 includes an antenna-integrated MMIC and a microcomputer, the antenna-integrated MMIC may have the parts of the radar control unit 44 excluding the signal processing unit 89 (the transmission control unit 80 and the radar transmission and reception circuit 81) and the transceiver unit 43, and the microcomputer may be configured to have the signal processing unit 89 and the processing unit 62.

[0046] The processing unit 62 includes a storage unit 63, a calculation unit 64, a distribution determination unit 911, an extraction unit 912, and a candidate determination unit 913. The storage unit 63 stores various set values ​​(data) related to the operation of the level meter 10. The calculation unit 64 performs various calculations related to the operation of the level meter 10 based on the set values ​​stored in the storage unit 63 and the signal processing results of the signal processing unit 89. The storage unit 63 includes a storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The calculation unit 64 includes a processor such as a CPU (Central Processing Unit). The storage unit 63 and the calculation unit 64 may be provided on the display board 60 of the housing 15. Alternatively, the sensor unit 16 and the housing 15 may be provided with separate storage units 63 and calculation units 64, respectively, and the data to be stored and the calculation processing to be handled may be shared between the sensor unit 16 and the housing 15. 4, the calculation unit 64 and the radar transmitting / receiving circuit 81 and signal processing unit 89 of the radar control unit 44 collectively function as a measurement value determining unit 88. The measurement value determining unit 88 performs processing to determine a measurement value related to the distance or level Y of the contained item 72 from the level meter 10, based on the reflection signal Rx received by the receiving circuit 43R and container information related to the container 70 (such as the height of the container 70).

[0047] The distribution determining unit 911 determines the reception intensity distribution of the reflected signal Rx with respect to the distance from the level meter 10, based on the reception intensity of the reflected signal Rx received by the receiving circuit 43R. The extracting unit 912 extracts peak positions and peak intensities from the reception intensity distribution determined by the distribution determining unit 911. The candidate determining unit 913 extracts multiple combinations of peak positions and peak intensities from the reception intensity distribution determined by the distribution determining unit 911 using the extracting unit 912, and determines them as multiple peak candidates.

[0048] On the other hand, the display board 60 of the housing 15 has a setting unit 61, an input unit 65, and an output unit 66. The setting unit 61 performs processing to sequentially set container information related to the container 70 and a plurality of level setting values ​​related to the level Y. The input unit 65 is an interface circuit that inputs an input provided from outside the level meter 10 as a signal to the level meter 10. Examples of the input provided from outside the level meter 10 include a user's operation on the operation unit 30 and a control signal provided from an external device (such as the management device 90) via the external input terminal 12C. The input unit 65 stores, for example, flag information indicating that the operation unit 30 has been operated and data such as a setting value provided via the external input terminal 12C in the storage unit 63.

[0049] The output unit 66 is an interface circuit that outputs to the outside a signal generated inside the level meter 10. For example, the output unit 66 changes the display content of the display unit 20 and the lighting state of the status lamp 52 according to the calculation result (such as the value of the level Y) by the calculation unit 64. The output unit 66 also transmits the calculation result by the calculation unit 64 to an external device via the external output terminal 12D.

[0050] Measurement of the level Y by the level meter 10 will be described in more detail with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing an example of the configuration of the radar transmission / reception circuit 81 and the transmission / reception unit 43 included in the sensor IC 41. Fig. 6 is a diagram showing the relationship between the measurement signal Tx and the reflected signal Rx.

[0051] As shown in FIG. 5, the radar transmission / reception circuit 81 includes a ramp generator 82, a power amplifier 83, a low-noise amplifier 84, a mixer 85, a low-pass filter 86, and an analog-to-digital converter 87.

[0052] The level meter 10 of this embodiment measures the level Y by a radar method using FMCW. The ramp generator 82 is connected to the transmission control unit 80. When the ramp generator 82 receives data indicating the waveform of the measurement signal Tx determined by the transmission control unit 80, it generates a signal having a waveform according to the data. In this embodiment, a waveform that repeatedly increases and decreases in frequency is used as the waveform of the measurement signal Tx.

[0053] FIG. 6 shows a graph showing the change in frequency of the measurement signal Tx (and the reflected signal Rx) over time. In FIG. 6, the frequency of the measurement signal Tx increases linearly from the minimum value (Min) as time passes, and when it reaches the maximum value (Max), it returns to the minimum value again. In this way, the frequency of the measurement signal Tx repeatedly increases and decreases. Note that the frequency increase and decrease pattern is not limited to this, and it is sufficient that the measurement value determination unit 88 can calculate the level Y based on the comparison between the measurement signal Tx and the reflected signal Rx. For example, a pattern may be used in which the frequency decreases linearly from the maximum value as time passes, and when it reaches the minimum, it returns to the maximum value again. Also, a pattern in which the frequency increases and decreases linearly between the maximum value and the minimum value may be used. The measurement signal Tx used in this embodiment is a radio wave in the 60 GHz band, and the minimum value of the frequency is, for example, 58 GHz, and the maximum value is, for example, 69 GHz. Note that the frequency band used is not limited to this, and for example, a frequency of 77 GHz to 81 GHz may be used.

[0054] The signal generated by the ramp wave generator 82 in Fig. 5 is amplified by a power amplifier 83 and sent to the transmission circuit 43T. The transmission circuit 43T generates radio waves with a waveform corresponding to the sent signal and transmits the radio waves as a measurement signal Tx to the contained item 72. The measurement signal Tx is reflected by the interface 74 of the contained item 72 to become a reflected signal Rx, which is received as a received signal by the receiving circuit 43R. The reflected signal Rx becomes a wave out of phase with the measurement signal Tx.

[0055] As shown by the dashed line in Fig. 6, the reflected signal Rx is a wave that is shifted from the measurement signal Tx by a time difference Δt. This time difference Δt is a value that corresponds to the distance YA (Fig. 3) from the measurement end 40 to the interface 74 of the contents 72. Because the reflected signal Rx travels back and forth between the measurement end 40 and the contents 72, there is a relationship of Δt = 2 × YA / c, where c is the speed of light.

[0056] Then, a frequency difference ΔF occurs between the measurement signal Tx and the reflected signal Rx according to the magnitude of the time difference Δt. There is a certain relationship between the frequency difference ΔF and the time difference Δt that depends on the waveform of the measurement signal Tx. The waveform of the measurement signal Tx is a waveform in which the frequency changes linearly with the passage of time. In other words, there is a certain relationship between the frequency difference ΔF and the time difference Δt that depends on the frequency change per unit time in the waveform of the measurement signal Tx. For example, the frequency of the measurement signal Tx increases linearly from the minimum value (Min) as time passes, and reaches the maximum value (Max). In this case, the relationship between the frequency difference ΔF and the time difference Δt is uniquely determined by the difference between the maximum and minimum values ​​of the frequency of the measurement signal Tx, which is the bandwidth of the frequency modulation, and the relationship of the frequency change with the passage of time. Therefore, the level meter 10 can calculate the time difference Δt based on the frequency difference ΔF, which is the difference between the measurement signal Tx and the reflected signal Rx. Then, the level meter 10 can calculate (Δt×c / 2). Furthermore, the level meter 10 can calculate the value of the level Y based on the distance YA. Specifically, the difference between the height of the container 70 (the distance from the bottom of the container 70 to the top surface inside the container 70) and the distance YA is the value of the level Y. Therefore, the measurement value determination unit 88 can determine the level Y of the contained contents 72 based on the reflection signal Rx received by the receiving circuit 43R and the container information about the container 70 (such as the height of the container 70). The container information about the container 70, such as the height of the container 70, the bottom distance Y0 from the level meter 10 to the bottom of the container 70, and the top distance Y1 from the level meter 10 to the top surface inside the container 70 (the thickness of the top plate of the container 70 in FIG. 3), may be set in advance by the setting unit 61 before the measurement of the level Y is started. Note that the distance from the level meter 10 is, more precisely, the distance from the measurement reference plane XS (a plane on which the distance value is treated as zero) that is the measurement reference in the level meter 10. The position of the measurement reference plane XS is determined in advance before the level meter 10 is used (for example, when the level meter 10 is designed). For example, the position where the level gauge 10 is attached to the container 70 (the position of the outer upper surface of the container 70 in FIG. 3) is determined as the measurement reference surface XS. In terms of the position inside the level gauge 10, the lower surface of the mounting part 17 (the upper end of the mounting screw part 18) becomes the measurement reference surface XS.In addition, since there is a certain relationship between the frequency difference ΔF and the time difference Δt that depends on the waveform of the measurement signal Tx, the correspondence relationship between the frequency difference ΔF and the distance YA can be obtained in advance. The correspondence relationship between the frequency difference ΔF and the distance YA may be stored in the storage unit 63 in advance.

[0057] 5, a received signal corresponding to the reflected signal Rx received by the receiving circuit 43R is input to a mixer 85 via a low-noise amplifier 84. A signal corresponding to the waveform of the measurement signal Tx output from the ramp generator 82 is also input to the mixer 85, and the mixer 85 generates a mixed signal Mx by mixing the waveforms of the measurement signal Tx and the reflected signal Rx. The mixer 85 included in the radar transmitting and receiving circuit 81 functioning as part of the measurement value determining unit 88 specifically mixes the measurement signal Tx and the reflected signal Rx to generate an IF signal (IF: Intermediate Frequency) as the mixed signal Mx.

[0058] The IF signal (intermediate frequency signal) has a waveform that includes high frequency components originating from the 60 GHz band frequencies of the measurement signal Tx and the reflected signal Rx, and low frequency components corresponding to the frequency difference ΔF between the measurement signal Tx and the reflected signal Rx. The IF signal is input to a low-pass filter 86, which extracts a low frequency waveform corresponding to the frequency difference ΔF. The extracted low frequency waveform is input to an analog-to-digital converter 87. The analog-to-digital converter 87 converts the low frequency waveform into a digital value and outputs it to a signal processing unit 89.

[0059] A signal processing unit 89, which functions as part of the measurement value determination unit 88, converts the low-frequency waveform output from the analog-digital converter 87 into a frequency signal Px by fast Fourier transform processing or the like. The frequency signal Px is a signal that indicates the wave strength for each frequency, and in this frequency signal Px, a target peak PS originating from a reflected signal Rx caused by reflection of the measurement signal Tx at the interface 74 appears. The frequency corresponding to this target peak PS is the frequency difference ΔF between the measurement signal Tx and the reflected signal Rx. The signal processing unit 89 transmits the frequency signal Px to the calculation unit 64 in FIG. 4.

[0060] The calculation unit 64, which functions as a part of the measurement value determination unit 88, calculates the values ​​of the distance YA and the level Y based on the frequency signal Px. When calculating the values ​​of the distance YA and the level Y, the calculation unit 64 refers to information stored in the storage unit 63. For example, the storage unit 63 stores the correspondence between the frequency difference ΔF and the distance YA, values ​​for calculating the level Y from the distance YA (container information such as the height of the container 70), and the like.

[0061] After calculating the frequency difference ΔF corresponding to the target peak PS of the frequency signal Px, the calculation unit 64 calculates the distance YA and the value of the level Y based on the frequency difference ΔF and the information stored in the storage unit 63. In this way, the calculation unit 64, which functions as a part of the measurement value determination unit 88, determines the level Y of the contained item 72 based on the intermediate frequency signal. The calculation unit 64 transmits the calculated value of the level Y to the output unit 66. The output unit 66 changes the display content of the display unit 20 and the lighting state of the status light 52 according to the value of the level Y. The value of the level Y is also sent to the management device 90 (FIG. 3) through the external output terminal 12D. The output unit 66 may output a binary or multi-value control signal based on the result of comparing the calculated value of the level Y with a threshold value to the management device 90 through the external output terminal 12D. Also, instead of the value of the level Y itself, a signal indicating that a specific control should be executed according to the state of the level Y may be sent to the management device 90. For example, when level Y rises above or falls below a particular threshold a signal may be sent to management device 90 indicating that operation of pumps, valves, etc. should be altered.

[0062] Depending on the measurement environment, a peak other than the target peak PS as shown in Fig. 5 may appear in the frequency signal Px due to an element other than the interface 74 of the contained object 72. For example, as shown in Fig. 3, the measurement signal Tx is reflected by the container built-in object 73 (a stirrer, a ladder, etc.) and an ambient signal R different from the reflected signal Rx from the interface 74 may appear. N Then, in addition to the target peak PS, the surrounding signal R NTherefore, multiple peaks occur in the frequency signal Px.

[0063] In such a case, the calculation unit 64, the radar transmission / reception circuit 81, and the signal processing unit 89, which function as the measurement value determination unit 88, can determine the measured distance value corresponding to each of the multiple peaks that have occurred. The measured distance value corresponding to a peak indicates the distance from the level meter 10 at which the peak originates from the signal reflected. The distribution determination unit 911 determines the distribution of the measured signal Tx and the reflected signal Rx (ambient signal R N By utilizing the correspondence between the frequency difference ΔF between the level meter 10 and the distance YA (including the frequency difference ΔF between the level meter 10 and the distance YA), it is possible to determine a reception intensity distribution that indicates the relationship between the intensity of the signal received by the level meter 10 and the distance from the level meter 10 at which the signal is reflected.

[0064] An example of the reception intensity distribution is shown in a graph in Fig. 7. In the graph in Fig. 7, multiple peak candidates (peaks that may be the target peak PS originating from the interface 74 of the contained item 72) appear. N is the ambient signal R reflected at the interface 74 of the content 72 N It comes from.

[0065] The extraction unit 912 extracts the peak position and peak intensity of each peak from the reception intensity distribution determined by the distribution determination unit 911. The peak position corresponds to the distance from the level meter 10 to the element (e.g., the interface 74 of the contained item 72, the container built-in object 73, etc.) that reflects the measurement signal Tx in the container 70. The peak intensity corresponds to the intensity of the reflected signal Rx resulting from the reflection of the measurement signal Tx. Note that in the following description, the reflected signal Rx reflected by the interface 74 and the ambient signal R reflected by the container built-in object 73, etc. are referred to as the "peak position" and the "peak intensity". N These are sometimes collectively referred to as the reflected signal Rx.

[0066] The candidate determining unit 913 extracts a plurality of combinations of peak positions and peak intensities and determines them as a plurality of peak candidates. The peak candidates include a target peak PS originating from the interface 74 of the contents 72 and a surrounding peak P originating from the contents 73 of the container. N Then, the multiple peak candidates determined by the candidate determining unit 913 based on the reception intensity distribution are displayed on the display unit 20. The user selects a target peak PS corresponding to the position of the interface 74 of the content 72 (the distance from the level meter 10) from the multiple peak candidates.

[0067] By performing appropriate calculations, the measurement value determining unit 88 can remove peak candidates other than the target peak PS from the reception intensity distribution and determine the distance YA or level Y of the contained item 72 based on the target peak PS. For example, the measurement value determining unit 88 can remove peak candidates other than the target peak PS from the reception intensity distribution by performing mask processing and background processing on the reception intensity distribution. By removing peak candidates other than the target peak PS from the reception intensity distribution, the measurement value determining unit 88 can determine the measurement value of the contained item 72 based only on the target peak PS. The measurement value determining unit 88 can then determine the measurement value of the contained item 72 based on only the target peak PS. N The measurement value of the contents 72 can be determined correctly even in an environment where the surrounding peak P N In order to remove unnecessary information such as the above, the measurement signal Tx, the reflected signal Rx, and the surrounding signal R N Therefore, the user can complete the setting of the measurement conditions required for measuring level Y with the simple operation of selecting the target peak PS from the given options.

[0068] (About mask processing) For example, a peak occurs at a position far away from the level meter 10 (the surrounding peak P N) may be due to a signal reflected at the bottom of the container 70. In order to remove the peak due to the signal reflected at the bottom of the container 70, signals generated at positions close to the distance from the level meter 10 to the bottom may be ignored.

[0069] In addition, the peaks occurring at positions close to the level meter 10 (surrounding peaks P N ) may be due to internal reflections close to the level meter 10. To eliminate the peaks due to internal reflections close to the level meter 10, signals emitted at positions close to the level meter 10 can be ignored.

[0070] For example, as shown in FIG. 7, the area of ​​the reception intensity distribution that is far from the level meter 10 and the area that is far from the level meter 10 are masked areas W A The measurement value determining unit 88 may set the mask area W A Ignore the signal within the mask area W (do not treat it as a valid signal). A Data on whether to set the level as the maximum level can be calculated in advance based on data on the installation environment of the level meter 10 (such as the height dimension of the container 70), for example.

[0071] (About background processing) In addition, the container-integrated object 73 always exists at a fixed position inside the container 70. Therefore, the surrounding signal R reflected by the container-integrated object 73 N The surrounding peak P N appears as a constant waveform in the received intensity distribution, regardless of the fluctuation of the level Y of the contained object 72. N The surrounding peak P N To remove the surrounding peaks P N The waveform data of the background signal W B Among the waveform data included in the reception intensity distribution, the background signal W B Any waveform data that matches or is close to the waveform data in the above may be ignored.

[0072] For example, from the waveform data of the reception intensity distribution determined by the distribution determination unit 911, the background signal W B By subtracting the waveform data of the surrounding peak P from the reception intensity distribution, N Once the peak candidate is identified as the target peak PS, the background signal W is removed from the received intensity distribution. B For example, the level meter 10 allows the user to select a target peak PS from a number of peak candidates. The measurement value determination unit 88 calculates the waveform data of the peak candidates appearing in the reception intensity distribution other than the selected target peak PS as a background signal W. B The background signal W may be stored in the storage unit 63 as waveform data. Note that the level meter 10 may measure the background signal W beforehand without the contents 72 (when the container 70 is empty). B It is also possible to obtain waveform data.

[0073] (Regarding tracking processing) When mask processing or background processing is performed, the position of the target peak PS is within the mask area W A or the waveform of the target peak PS is different from the background signal W B In order for the measurement value determining unit 88 to be able to determine the measurement value of the contained item 72 even in such a case, it is preferable to perform a tracking process of the target peak PS.

[0074] The level Y of the contents 72 changes continuously in the container 70, and is unlikely to fluctuate suddenly. A or the waveform of the target peak PS is different from the background signal W BIf the value of level Y was able to be measured immediately before, even if the waveform of the target peak PS becomes similar to that of the previous measurement, then the current level Y is expected to be close to the previous measurement value. Therefore, when the measurement value determining unit 88 loses sight of the target peak PS during measurement, it uses a tracking process to estimate that the target peak PS is near the position where it was lost (the distance from the level meter 10), and then performs measurement. For example, the measurement value determining unit 88 may estimate the current position of the target peak PS based on the position immediately before the target peak PS was lost and the rate of change of the target peak PS over time up until that point. Then, if the target peak PS continues to fluctuate, the mask area W A and the background signal W B When the signal passes through this region, a new peak will appear near the position of the estimated target peak PS, and the measurement value determining section 88 should then perform measurement using this new peak as the target peak PS.

[0075] It is preferable that the user can set how long the measurement value determining unit 88 will perform tracking processing when it loses sight of the target peak PS during measurement, and how far the estimated position of the target peak PS will be estimated. A and the background signal W B Since there are cases where the target peak PS is fixed (the level Y maintains a constant value) in this region, the tracking process may be set so as not to be released over time.

[0076] (About strength priority and short distance priority) In addition, when multiple peaks exist within the distance range from the level meter 10 where the target peak PS is expected to exist, it is preferable to select from several methods which peak is regarded as the target peak PS. For example, there is an intensity-prioritized method in which a peak with a large signal intensity (signal amplitude) is preferentially regarded as the target peak PS, and a short-distance-prioritized method in which a peak at a position with a small distance (close distance) from the level meter 10 is regarded as the target peak PS. Basically, the intensity-prioritized method is preferably selected, but for example, when the measurement signal Tx is reflected multiple times between the interface 74 and the inner wall of the container 70, peaks with high intensity originating from the interface 74 are generated at multiple positions. In that case, since the peak at a short distance is considered to correspond to the first reflection at the interface 74, it is preferable that the peak at a short distance is regarded as the target peak PS. It is also preferable that the user can set whether the intensity-prioritized method or the short-distance-prioritized method is selected.

[0077] Next, the state transition of the level meter 10 will be described with reference to FIG. 8. First, when the level meter 10 is started, the initial setting 100 is started. In the initial setting 100, various setting screens for sequentially setting the operating conditions of the level meter 10, including container information (such as the height of the container 70) and a level setting value (a value related to the level Y, such as a threshold value), are sequentially displayed on the display unit 20. Note that in the initial setting 100, the operating conditions of the level meter 10, such as whether the level meter 10 outputs an analog signal for a measured value or communicates serially with an external device, may be set. On the other hand, there may be an operating condition that is not displayed in the initial setting 100 and is not set by the user. For example, an operating condition that one of the terminals included in the external output terminal 12D outputs an analog value may be predetermined regardless of a user's operation. In addition, an operating condition that communication with an external device is automatically performed according to an external device connected to the level meter 10 may be predetermined. For example, when the level meter 10 is connected to a device (master device) that manages the level meter 10, communication between the level meter 10 and the master device may be automatically performed using IO-Link communication specified in IEC 61131-9 (IEC: International Electrotechnical Commission).

[0078] Once the initial setting 100 is complete, the level meter 10 enters the measurement mode 500. In the measurement mode 500, the level meter 10 measures the level Y of the contained content 72. In the measurement mode 500, the relative position of the level setting value with respect to the container 70 is displayed on the display unit 20 together with the bar display 22, as shown in FIG.

[0079] In the measurement mode 500, the display unit 20 can display a menu screen 600. The display screen of the measurement mode 500, which displays the bar display 22 and the like, and the menu screen 600 can transition back and forth. For example, each time the user operates the menu key 32 in the measurement mode 500, the display content of the display unit 20 may be switched between the display screen of the measurement mode 500 and the menu screen 600.

[0080] FIG. 9 shows an example of a menu screen 600. The menu screen 600 displays a plurality of options corresponding to individual setting contents. In response to a user's selection, the display content of the display unit 20 transitions from the menu screen 600 to an individual setting screen such as a container setting screen 610 (in FIG. 9, the character string "Basic Installation Settings"), a setting value change screen 620, a various setting screen 630, and an adjustment function 800. The menu screen 600 and the individual setting screens can transition to each other. For example, it is preferable that when the menu key 32 and the up key 36 are operated simultaneously on an individual setting screen, the display unit 20 returns to the menu screen 600.

[0081] When the character string "adjust function" is selected on the menu screen 600, the level meter 10 starts the adjustment function 800. The various processes included in the adjustment function 800 may be realized, for example, by the calculation unit 64 executing a program stored in the storage unit 63. FIG. 10 shows state transitions of the level meter 10 in the adjustment function 800. When the adjustment function 800 is started, the level meter 10 first displays a current value display screen 801 on the display unit 20. The current value displayed on the current value display screen 801 is a measurement value related to the level Y determined by the measurement value determination unit 88 at that time. For example, the measurement value determination unit 88 determines, for example, the peak position with the strongest intensity among the combinations of peak positions and peak intensities (peak candidates) determined by the candidate determination unit 913 as the measurement value related to the level Y. The peak position with the strongest intensity corresponds, for example, to the value of the distance from the level meter 10 to the interface 74 of the contents 72. However, at this point, the distance of an element other than the interface 74, such as the container's built-in contents 73, may be displayed.

[0082] The current value display screen 801 can also transition to an adjustment mode selection screen 810. In the adjustment mode selection screen 810, the user selects whether to perform the process for determining the correct measurement value for the contained item 72 by removing peak candidates other than the target peak PS from the reception intensity distribution in the optimization mode 820 or in the limited mode 860. In both the optimization mode 820 and the limited mode 860, the user selects which of the multiple peak candidates is the target peak PS originating from the contained item 72. Then, in the optimization mode 820, diagnosis and setting optimization are performed. Specifically, based on the reception intensity distribution, a diagnosis is performed on the measurement environment of the measurement value (such as level Y) for the contained item 72. Depending on the diagnosis result, a suggestion message showing guidance on the measurement environment is displayed on the display unit 20. In the optimization mode 820, optimization of the settings (such as tracking processing settings) required to determine the measurement value for the contained item 72 is performed based on the target peak PS selected by the user and the diagnosis result.

[0083] On the other hand, in the limited mode 860, only learning based on the target peak PS designated by the user is executed. Learning is a setting related to the reception intensity distribution that is performed based on the designated target peak PS. A specific example is a setting for removing peak candidates other than the target peak PS from the reception intensity distribution (for example, a mask area W A , background signal W B In limited mode 860, no other setting changes are made.

[0084] 11 is a flow diagram showing the flow of processing in the optimization mode 820. When the optimization mode 820 starts, first in step 821, the candidate determining unit 913 determines a plurality of peak candidates (candidate detection).

[0085] Once the determination of the peak candidates has been completed, in step 822, a process (candidate selection) is performed in which the user is prompted to select one of the multiple peak candidates as the target peak PS originating from the contents 72 to be measured.

[0086] In the candidate selection process, the display unit 20 displays information on the measurement value and reception strength corresponding to each of the peak candidates. The user selects a peak candidate that is thought to represent the measurement value (distance from the level meter 10) of the contents 72 to be measured as the target peak PS, referring to the measurement value and the stability of the reception strength. For example, if the user knows the design value of the container information (height, etc.) of the container 70, the user can distinguish between the peak candidate originating from the inner surface of the container 70 or the contents 73 contained in the container and the target peak PS originating from the contents 72. Also, for example, if the contents 72 are liquid and the liquid surface is shaking, the user can estimate that the peak with unstable signal strength is the target peak. Here, the display unit 20 also displays options of "empty" and "not applicable". If the container 70 does not contain the contents 72 (the container 70 is empty), the user may select the option of "empty". The option of "empty" may also include the distance from the level meter 10 to the bottom of the container 70. The user may also select the "N / A" option when he or she believes that none of the displayed peak candidates represent the measured value of the contents 72 being measured.

[0087] In step 823, it is determined whether the option "not applicable" is selected. If the option "not applicable" is selected (YES in step 823), the level gauge 10 displays a suggestion message on the display unit 20 in step 840. The suggestion message in step 840 indicates that the level gauge 10 was unable to find the interface 74 of the contents 72 by measurement, and provides a suggestion for improving the measurement environment. For example, a message such as "Liquid level signal not found. Increase the sensitivity setting or review the installation" is displayed on the display unit 20. After displaying the suggestion message in step 840, the level gauge 10 ends the optimization mode 820 without performing learning or setting optimization.

[0088] Then, in step 823 of FIG. 11, if the “Not Applicable” option is not selected (NO in step 823), that is, if any of the peak candidates determined by the candidate determination unit 913 is selected as the target peak PS, the processing of the optimization mode 820 proceeds to step 825.

[0089] In step 825, a diagnosis regarding the measurement environment is performed based on the target peak PS and the reception intensity distribution. N For example, if the signal strength of the peak candidate selected by the user is extremely weaker than the other peak candidates, the surrounding signal R N It is determined that there is a problem with the relationship with the surrounding signal R N If there is a problem with the relationship (NO in step 825), a suggestion message is displayed on the display unit 20 in step 827.

[0090] The suggestion message displayed in step 827 is based on the ambient signal R N This shows that the influence of the surrounding signal R N This suggests that the intensity of the target peak PS may appear small due to the influence of the above. Therefore, the suggestion message in step 827 suggests that the installation of the level meter 10 itself should be reviewed. After the suggestion message in step 827 is displayed, the level meter 10 learns the user's designated value as the target peak PS, and ends the optimization mode 820.

[0091] On the other hand, the ambient signal R NIf there is no problem with the relationship (YES in step 825), the level meter 10 proceeds to step 828, where it calculates the short-distance measurement limit using the intensity of the peak candidate selected by the user, the peaks not selected among the peak candidates appearing in the short distance of the level meter 10, and data on reflections that may occur in the short distance due to sources other than the contents 72 (e.g., stray signal waves caused by internal reflections of the container 70, etc.). In calculating the short-distance measurement limit, the short-distance limit (how far can be measured) of the measurement range of the level meter 10 is confirmed. A reflected signal Rx from a position that is too close to the level meter 10 may be affected by internal reflections of the container 70, etc., so a valid measurement value can only be obtained from a position that is somewhat away from the level meter 10.

[0092] Next, in step 829, it is confirmed (diagnosed) whether there is any problem with the calculation result of the short distance measurement limit. For example, the calculated value of the short distance measurement limit is displayed on the display unit 20, and the user selects whether there is any problem with the distance as the short distance limit of the measurement range.

[0093] If there is a problem with the calculation result of the short-distance measurement limit (NO in step 829), the processing of the optimization mode 820 proceeds to step 830, and a suggestion message regarding the result of the distance measurement is displayed on the display unit 20. The suggestion message in step 830 may display, for example, that the sensitivity setting for short-distance measurement should be increased, that the installation of the level meter 10 should be reconsidered, and so on.

[0094] On the other hand, if there is no problem with the calculation result of the short-distance measurement limit (YES in step 829), the processing in optimization mode 820 proceeds to step 831, and optimization processing of the measurement conditions is started. After the optimization processing is completed, in step 832, a screen indicating that the optimization processing is completed is displayed on the display unit 20, and the optimization mode 820 is completed.

[0095] In step 831, a diagnosis of the measurement environment is performed based on the selected target peak PS and the reception intensity distribution. Then, depending on the diagnosis result, optimization of the settings required to determine the measurement value of the contained item 72 is performed. In the diagnosis of the measurement environment, it is estimated whether or not there is an element other than the contained item 72 that reflects the measurement signal Tx in the container 70, and if so, where the element is located. It is estimated that the selected target peak PS originates from a reflected signal Rx in which the measurement signal Tx is reflected by the contained item 72 to be measured, whereas the surrounding peak P N is the ambient signal R that is the measurement signal Tx reflected by elements other than the contents 72 N Therefore, the target peak PS and the surrounding peaks P N From the relationship between the mask area W and the object 72, it is possible to make inferences about factors other than the object 72. In optimizing the settings required to determine the measurement value of the object 72, the measurement conditions required for the level meter 10 to continue to identify the position of the peak PS included in the reception intensity distribution object during the measurement are set. For example, A and background signal W B In addition to the above settings, the intensity priority or short distance priority can be set when selecting the peak position, and the tracking duration and estimated position range can be set.

[0096] FIG. 12 shows an example of the settings according to the diagnosis result (state of the measurement environment). FIG. 12 shows the items "Peak Selection", "Tracking", and "Learning" which indicate the settings to be applied. The "Peak Selection" item is a setting for which peak is to be preferentially regarded as the target peak PS when multiple peaks exist (for example, intensity priority or short distance priority). The "Tracking" item is a setting for whether, when the level meter 10 loses sight of the target peak PS, it is recommended that the tracking process for searching for a peak near the position where it was lost be terminated in a short time or continued for a long time. The "Learning" item is a setting for the reception intensity distribution, for example, whether the mask area W A , background signal W BThis setting is for whether or not it is recommended to store (learn) data required for removing peak candidates other than the target peak PS, such as data regarding .

[0097] For example, if the intensity of the target peak PS is higher than that of other peak candidates (surrounding peaks P N If the intensity of the target peak PS is expected to be stronger than the intensity of the mask region W, the intensity of "Peak Selection" is set to "Intensity Priority Recommended". A and the background signal W B If you expect to stay in the area for a long period of time, the "Tracking" item is set to "Long Term Recommended". N If the level meter 10 can identify the target peak PS without removing the target peak PS, the "Learning" item is marked as "Not Executed."

[0098] In FIG. 12, the state of the measurement environment (diagnosis result) is classified into state A, state B, state C, etc., and appropriate setting contents are predetermined for each state. By applying the predetermined appropriate setting contents, the settings necessary for determining the measurement value related to the distance or level Y of the contained item 72 are automatically optimized. For example, if the state of the measurement environment is "A", the settings applied are "intensity priority recommended" for the peak selection setting, "short time recommended" for the tracking setting, and "execute" for the learning setting. As shown in FIG. 12, depending on the state, the peak selection setting may be "short distance priority recommended", the tracking setting may be "long time recommended", and the learning setting may be "execute".

[0099] When the optimization process of the optimization mode 820 (FIG. 11) is completed as described above, the setting items related to the measurement of the level Y, particularly the setting items related to "peak selection", "tracking", and "learning", are automatically set. Since these settings are automatically performed by the level meter 10, the user only needs to select a level candidate corresponding to the target peak PS, and does not need to set each setting item in detail. In addition, in the optimization mode 820, if the measurement environment is inappropriate, a suggestion message for improving the measurement environment is displayed on the display unit 20. By checking the suggestion message, the user can understand the work that should be done to perform a correct measurement (for example, reviewing the installation state of the level meter 10). Therefore, the level meter 10 of this embodiment is highly convenient for the user.

[0100] However, since the automatically set setting items are merely "recommended", they may not be optimal settings depending on the measurement environment. Therefore, it is preferable that the various setting items can be changed according to the user's wishes. For example, by selecting an option (character string "Settings") of the various setting screen 630 on the menu screen 600 of FIG. 9, a screen for changing various measurement conditions including setting items such as "Peak Selection" and "Tracking" may be displayed on the display unit 20. Furthermore, according to the user's wishes, optimization of settings required to determine a measurement value related to the distance or level Y of the contained object 72 may be performed in a question and answer format (wizard format). Specifically, questions related to the measurement conditions of the level Y (for example, container information related to the dimensions of the container 70, questions related to the presence or absence of the container built-in object 73, etc.) are displayed on the display unit 20, and the user inputs answers to the questions. Then, the measurement value determination unit 88 performs optimization of settings required to determine a measurement value related to the distance or level Y of the contained object 72 based on the input answers.

[0101] Next, a case where the limited mode 860 is selected on the adjust mode selection screen 810 in Fig. 10 will be described. Fig. 13 shows a flow diagram of the process flow in the limited mode 860. When the limited mode 860 is started, first, in step 861, a screen (execution result presence / absence display) showing whether or not there is an existing learning execution result is displayed on the display unit 20.

[0102] A number of options are displayed on the execution result display screen. The options in the execution result display include an option to return to the previous screen (adjust mode selection screen 810) ("Back") and an option to execute learning ("Execute"). If there is an existing learning execution result (if the surrounding peak P N Mask area W to remove A , background signal W B etc. have been completed), a display indicating that there is an existing learning result (for example, "Learning execution result: Yes") is displayed. Also, if there is an existing learning execution result, the options in the execution result presence / absence display include an option to erase the existing learning execution result ("Erase"). When the user selects the "Erase" option in step 861 (for example, operates menu key 32 with the "Erase" option displayed), the processing in limited mode 860 proceeds to step 862.

[0103] In step 862, a screen (deletion confirmation) for confirming whether or not the existing learning execution results should really be deleted is displayed on display unit 20. In step 862, the user selects whether or not to delete the existing learning execution results. If it is selected not to delete (NO in step 862), the display on display unit 20 returns to the screen displaying the presence or absence of execution results (return to step 861).

[0104] If the user selects to erase the existing learning execution result in step 862 (YES in step 862), the process of the limited mode 860 proceeds to step 863, where information on the already selected target peak PS and information for removing peak candidates other than the target peak PS from the reception intensity distribution (mask area W A , background signal W B When the existing learning execution results are erased, the process of the limited mode 860 returns to step 861.

[0105] Learning execution is started when the user selects the option "Execute" in step 861. When learning execution is started, the process of the limited mode 860 proceeds to step 864, where a process (candidate selection) is performed in which the user is prompted to select one of the multiple peak candidates determined by the candidate determination unit 913 as the target peak PS originating from the content 72 to be measured.

[0106] In the candidate selection in step 864 in the limited mode 860, a screen similar to that in the candidate selection in step 822 (FIG. 11) in the optimized mode 820 is displayed on the display unit 20. The candidate selection screen may include options of "not applicable" and "empty".

[0107] After the candidate selection in step 864, it is determined in step 865 whether the option "not applicable" has been selected. If the option "not applicable" has been selected (YES in step 865), a numerical value input process is performed in step 866. In the numerical value input process, the user specifies and inputs the current numerical value of the measurement value of the contained item 72 to be measured.

[0108] After a numerical value is entered in step 866, or if the “Not Applicable” option is not selected (NO in step 865), that is, if any of the peak candidates determined by the candidate determination unit 913 is selected as the target peak PS, processing of the limited mode 860 proceeds to step 867.

[0109] In step 867, the peak candidate selected by the user or the peak at the peak position of the numerical value input by the user is stored as the target peak PS, and settings for removing other peak candidates from the reception intensity distribution (e.g., mask area W A , background signal W B Then, a screen indicating that the learning has been completed is displayed on the display unit 20, and the limited mode 860 is completed.

[0110] In the limited mode 860, the measurement conditions including the setting items such as "peak selection" and "tracking" that are automatically set in the optimization mode 820 are default settings that are determined in advance in the initial settings 100. The user may manually change the measurement conditions from the menu screen 600, etc., as necessary.

[0111] In the case of the optimization mode 820 in which diagnosis and setting optimization are performed, or in the limited mode 860 in which only learning is performed, a setting for removing peak candidates other than the target peak PS from the reception intensity distribution (for example, a mask area W A , background signal W B The above settings (settings such as above) are automatically performed by the measurement value determining unit 88. For example, when the user selects the target peak PS, the measurement value determining unit 88 automatically calculates the waveforms of the peak candidates (other than the selected target peak PS) that appear in the reception intensity distribution, based on the background signal W B Then, when the measurement value determining unit 88 determines the measurement value of the contained item 72, the background signal W B The waveform of the target peak PS is removed, and the distance or level Y of the content 72 from the level meter 10 is determined based on the target peak PS.

[0112] If the setting for removing peak candidates other than the target peak PS from the reception intensity distribution is automatically performed, the user can select the surrounding peaks P N In order to remove unnecessary information such as the above, the measurement signal Tx, the reflected signal Rx, and the surrounding signal R NTherefore, the user can complete the setting of the measurement conditions required for measuring level Y with the simple operation of selecting the target peak PS from the given options.

[0113] After a target peak PS is selected in the optimization mode 820 or the limited mode 860, it is preferable that only information related to the measurement value and reception intensity corresponding to the target peak PS is displayed as a peak candidate until information related to the target peak PS is erased, so that it is possible to confirm that peak candidates other than the target peak PS have been removed from the reception intensity distribution. For example, after the target peak PS is selected, when the adjustment function 800 is executed again and a screen for selecting peak candidates is displayed on the display unit 20, it is preferable that only information related to the selected target peak PS is displayed as a peak candidate.

[0114] Next, with reference to the drawings, a specific example of each display screen displayed on the display unit 20 in the adjustment function 800 of FIG. 10 will be described. In the description of the specific example of the display screen, the detailed description of the processing performed on each screen may be simplified. The order of the screen description does not necessarily match the order of the processing. First, FIG. 14 shows an optimization mode selection screen 810a and a limited mode selection screen 810b that function as the adjustment mode selection screen 810 of FIG. 10. The optimization mode selection screen 810a and the limited mode selection screen 810b include the value of the distance measured by the level meter 10 (here, 800 mm), as well as an interface position icon 131 and a reception intensity scale 890. In addition, a selection field 891 that displays options is displayed at the bottom of the current value display screen 801. In the optimization mode selection screen 810a, the selection field 891 displays the character string "Perform diagnosis and setting optimization". In the limited mode selection screen 810b, the selection field 891 displays the character string "Perform learning only". The display of this selection field 891 is switched when the user operates the down key 35 or the up key 36 .

[0115] The interface position icon 131 includes a figure 131a (a rectangle in FIG. 14) that imitates the level gauge 10, a figure 131b that imitates the container 70 and a line 131c that indicates the interface 74 of the contained item 72, which are arranged below the figure 131a, that imitates the level gauge 10, and an arrow 131d that extends from the figure 131a that imitates the level gauge 10 to the line 131c of the interface 74. The line 131c that indicates the interface 74 is displayed at a position in the figure 131b that imitates the container 70 that corresponds to a ratio according to the size of the measured value relative to the overall dimension of the container 70 (the height of the container 70). This interface position icon 131 visually indicates to the user that the displayed measured value indicates the distance from the level gauge 10 to the interface 74, and an indication of the ratio of the distance to the overall dimension of the container.

[0116] The receive intensity scale 890 indicates the reflected signal Rx or ambient signal R corresponding to the peak candidates on which the displayed measurements are based. N For example, the strength of the radio waves received by the receiving circuit 43R is classified into several stages (four stages in this example), and the reflected signal Rx or the surrounding signal Rx, which are the basis for calculating the displayed measurement value, is displayed. N The strength of the reflected signal Rx or the surrounding signal R is indicated by the number of reception intensity scales 890. N If the signal is strong, the number of reception strength scales 890 will be displayed (up to four). N If the reception strength is weak, fewer marks (minimum 1) will be displayed on the reception strength scale 890.

[0117] The number of reception intensity scales 890 changes dynamically depending on the strength of the radio waves received by the receiving circuit 43R at the time the display is being made. Therefore, if the strength of the radio waves received by the receiving circuit 43R is unstable, the number of reception intensity scales 890 will change in a short period of time. Note that the information on reception intensity may be displayed in a form different from the reception intensity scale 890 as long as it changes dynamically depending on the magnitude of the reception intensity. For example, the reception intensity may be displayed as a numerical value, or the stability of the intensity may be displayed in words such as "dynamic" (unstable) or "static" (stable).

[0118] Hereinafter, the interface position icon 131 and the reception intensity scale 890 may be displayed on other screens as well, but explanations and symbols relating to the interface position icon 131 and the reception intensity scale 890 on other screens will be omitted unless otherwise noted.

[0119] When the menu key 32 is operated on the optimization mode selection screen 810a, the optimization mode 820 (FIG. 11) is executed, and when the menu key 32 is operated on the limited mode selection screen 810b, the limited mode 860 (FIG. 13) is executed.

[0120] In both the optimization mode 820 and the limited mode 860, the wait screen 821 in Fig. 15 may be displayed on the display unit 20 while processing is being performed by the processing unit 62. For example, in the optimization mode 820, the wait screen 821 is displayed while the candidate determination unit 913 is determining a plurality of peak candidates (candidate detection). An animation image is displayed on the wait screen 821 to indicate that processing is awaiting in the processing unit 62. For example, as shown in Fig. 15, a plurality of rectangles are displayed side by side, and an animation is displayed in which the sizes of these rectangles change in sequence. The animation display is displayed each time processing is awaited, but a description thereof will be omitted hereafter.

[0121] Before the candidate selection of step 822 is made in optimization mode 820 (FIG. 11), the display 20 displays the candidate selection message shown in FIG. 16. The candidate selection message prompts the user to select a number representing the distance of the correct item 72 on the next screen.

[0122] When the menu key 32 is operated in response to the candidate selection message, a candidate confirmation screen shown in Fig. 17 is displayed on the display unit 20. The candidate confirmation screen in Fig. 17 includes a first candidate confirmation screen 822a, a second candidate confirmation screen 822b, a third candidate confirmation screen 822c, a fourth candidate confirmation screen 822d, and a cancel screen 822e. When the down key 35 or the up key 36 is operated, these screens are switched between each other.

[0123] The first candidate confirmation screen 822a displays that the container 70 is empty and the distance to the bottom of the container 70 in the empty state (1500 mm in this example). The display of the empty state is displayed in a selection field 891 at the bottom of the screen. No information indicating signal strength is displayed on the first candidate confirmation screen 822a. Also, the arrow included in the interface position icon 131 reaches the bottom of the figure representing the container 70.

[0124] The second candidate confirmation screen 822b displays the peak position (distance) value of the peak candidate, "800 mm," an interface position icon 131, and a reception intensity scale 890. The peak position value is displayed in a selection field 891. The reception intensity scale 890 on the second candidate confirmation screen 822b is four scale marks (strong signal).

[0125] The third candidate confirmation screen 822c displays the peak position value of the peak candidate, "1490 mm," an interface position icon 131, and a reception intensity scale 890. The reception intensity scale 890 on the third candidate confirmation screen 822c is three scale marks (the signal is slightly weak).

[0126] On the fourth candidate confirmation screen 822d, the character string "None" is displayed in the selection field 891 instead of the peak position value. When the user thinks that none of the peak candidates are appropriate as the position of the interface 74 of the content 72, the fourth candidate confirmation screen 822d is selected. No information indicating signal strength is displayed on the fourth candidate confirmation screen 822d. Furthermore, no arrow is displayed on the interface position icon 131.

[0127] The cancel screen 822e includes the character string "Back" in the selection field 891. The cancel screen 822e does not display information indicating the signal strength and the interface position icon 131. When the menu key 32 is operated on the cancel screen 822e, the display on the display unit 20 returns to the adjust mode selection screen (FIG. 14).

[0128] The user operates the menu key 32 on a screen (e.g., the second candidate confirmation screen 822b, the third candidate confirmation screen 822c) showing the peak positions of the peak candidates considered to correspond to the target peak PS, thereby selecting one of the peak candidates as the target peak PS. If the fourth candidate confirmation screen 822d (none) is selected in the optimization mode 820, a suggestion message is displayed on the display unit 20 indicating that the liquid level signal was not found and providing a suggestion for improving the measurement environment.

[0129] Figure 18 shows the user-selected peak of interest PS and the surrounding signal R N The suggestion message is shown when there is a problem with the relationship between the ambient signal R and the measurement by the level meter 10 (step 827 in FIG. 11). N This suggests that the impact of the level gauge 10 is significant, and also suggests that the installation of the level gauge 10 itself should be reviewed.

[0130] 19 shows a calculation result confirmation screen for the short distance measurement limit (step 829 in FIG. 11). The calculation result confirmation screen for the short distance measurement limit can be switched between a result negation screen 829a and a result approval screen 829b by operating the down key 35 or the up key 36. Operating the menu key 32 on the result negation screen 829a indicates that there is a problem with the calculation result of the short distance measurement limit. Operating the menu key 32 on the result approval screen 829b indicates that there is no problem with the calculation result of the short distance measurement limit.

[0131] 20 shows a suggestion message 830a when the calculation result of the short-distance measurement limit is undesirable (step 830 in FIG. 11). The suggested message 830a displayed here suggests that the installation of the level meter 10 should be reconsidered. The suggested message 830a also suggests that the short-distance sensitivity setting be increased (set to a higher sensitivity).

[0132] 21 shows a start confirmation screen for optimization processing. This screen is displayed when the optimization processing is started (step 831 in FIG. 11). The start confirmation screen for optimization processing can be switched between a positive start screen 831a and a negative start screen 831b by operating the down key 35 or the up key 36. The optimization processing is started by operating the menu key 32 on the positive start screen 831a. The optimization processing is cancelled by operating the menu key 32 on the negative start screen 831b, and the display on the display unit 20 returns to the adjust mode selection screen (FIG. 14).

[0133] FIG. 22 shows an optimization completion screen. This screen is displayed when the optimization process is completed (step 832 in FIG. 11). The optimization completion screen displays that the detection settings (measurement conditions) have been optimized and what specific settings have been made by the optimization. FIG. 22 shows that learning is performed, that the peak selection mode is set to "short distance priority", and that tracking is set to long time. Since the display content of the optimization completion screen contains a large amount of information, the display unit 20 may not be able to display all the information on one screen. In such a case, it is preferable that the display content of the optimization completion screen is scrolled by operating the down key 35 or the up key 36. Then, when all the display contents to be displayed are displayed and the scroll reaches the bottom, "OK" is displayed on the display unit 20. By operating the menu key 32 while this "OK" is displayed, the optimization is completed and the display of the display unit 20 returns to the adjust mode selection screen (FIG. 14).

[0134] Next, FIG. 23 shows a display screen (step 861 in FIG. 13) showing the presence or absence of a learning execution result in the limited mode 860. There are three types of display screens for the presence or absence of a learning execution result: a cancel selection screen 861a, a delete selection screen 861b, and a learning execution selection screen 861c. These screens include a display ("Yes") indicating that an existing learning execution result exists. If there is no existing learning execution result, a display such as "No" is made. The cancel selection screen 861a, the delete selection screen 861b, and the learning execution selection screen 861c differ in the character strings ("Back", "Delete", and "Execute") displayed in the selection field at the bottom of the screen. These screens can be switched between by the user operating the down key 35 or the up key 36. When the menu key 32 is operated with the selection field in the "Back" state (cancel selection screen 861a), the display of the display unit 20 returns to the adjust mode selection screen (FIG. 14).

[0135] 24 shows a confirmation screen for confirming whether or not to erase the learning execution result (step 862 in FIG. 13) and its screen transition. When menu key 32 is operated with the selection field for the display screen showing the presence or absence of the learning execution result in the "erase" state (erase selection screen 861b), the display on display unit 20 transitions to an erase denial screen 862a.

[0136] The selection field of the deletion negation screen 862a displays "No" to the effect that there is no need to delete the existing learning execution results. When the menu key 32 is operated on this screen, the display on the display unit 20 returns to the deletion selection screen 861b. The deletion negation screen 862a can be transitioned to and from the deletion affirmation screen 862b by operating the down key 35 or the up key 36.

[0137] The selection field on the deletion confirmation screen 862b displays a message indicating that the existing learning execution results should be deleted ("Yes"). When the menu key 32 is operated on this screen, the existing learning execution results are deleted, and the display on the display unit 20 transitions to a deletion completion screen 863. The deletion completion screen 863 displays a message indicating that the existing learning execution results have been deleted. When the menu key 32 is operated on the deletion completion screen 863, the display on the display unit 20 transitions to a deletion selection screen 861b. However, after the learning execution results have been deleted, the deletion selection screen 861b displays "none" for the existing learning execution results.

[0138] 25 shows a learning execution confirmation screen. When the menu key 32 is operated on the learning execution selection screen 861c, the display on the display unit 20 transitions to an execution affirmative screen 861d. The execution affirmative screen 861d can be switched between the execution affirmative screen 861d and a execution negative screen 861e by operating the down key 35 or the up key 36. When the menu key 32 is operated on the execution affirmative screen 861d, the execution of learning is started and a peak candidate is selected (step 864 in FIG. 13). When the menu key 32 is operated on the execution negative screen 861e, the display on the display unit 20 returns to the learning execution selection screen 861c.

[0139] As in the optimization mode 820, in the limited mode 860, when selecting a peak candidate, the candidate confirmation screen of FIG. 17 is displayed on the display unit 20. Then, when an option indicating "not applicable" (fourth candidate confirmation screen 822d) is selected in the limited mode 860, the display on the display unit 20 transitions to a numeric input screen relating to distance, as shown in FIG. 26. On the numeric input screen, the user can continuously change the numeric value of the distance displayed in the selection field by operating the down key 35 or the up key 36. The user adjusts the displayed numeric value to an appropriate value as the peak position of the target peak PS, and then operates the menu key 32 to input the distance value of the target peak PS.

[0140] 27 shows a learning completion screen in the limited mode 860. This screen is displayed when learning is completed in the limited mode 860 (step 867 in FIG. 13). When the menu key 32 is operated on this screen, the display on the display unit 20 returns to the adjust mode selection screen (FIG. 14).

[0141] Next, another example of the level meter 10 will be described with reference to Fig. 28. Fig. 28 is a perspective view showing another example of the level meter 10. In Fig. 28, components having the same functions as those in the level meter 10 in Figs. 1 and 2 are denoted by the same reference numerals as in Figs. 1 and 2, and descriptions thereof will not be repeated unless necessary.

[0142] The housing 15 of the level meter 10 in Fig. 28 includes a base portion 15a and a terminal portion 21. The base portion 15a is disposed on one end side (lower side) of the housing 15 in the longitudinal direction A (direction of the measurement axis). The terminal portion 21 is disposed on the other end side in the longitudinal direction A. In Fig. 28, the display unit 20 is provided on the terminal portion 21. Moreover, the terminal portion 21 is separable from the base portion 15a. The base portion 15a is cylindrical, while the terminal portion 21 is prismatic.

[0143] The terminal unit 21 may be fixed to the base unit 15a by a fastening screw on the rear side of the display unit 20. A connector for transmitting an electric signal between the base unit 15a and the terminal unit 21 may be provided. For example, one of a pair of connectors may be provided on the base unit 15a, and the other of the pair of connectors may be provided on the terminal unit 21. By connecting the pair of connectors, it becomes possible to transmit and receive an electric signal between the base unit 15a and the terminal unit 21. When the terminal unit 21 is separated from the base unit 15a, the connectors between the base unit 15a and the terminal unit 21 are connected via a cable for transmitting and receiving an electric signal. This allows the display unit 20 to display according to the measured level Y even when the terminal unit 21 is separated from the base unit 15a. In this way, when the terminal unit 21 is capable of being separated from the base unit 15a, the user can check the display of the display unit 20 at a position away from the base unit 15a. For example, if the level meter 10 is placed at a position higher than the user's viewpoint, it may be difficult for the user to check the display of the display unit 20. If the terminal unit 21 is detachable from the base unit 15a, the user can easily check the display unit 20 at the site where the container 70 is installed by pulling the terminal unit 21 to the height of the user's viewpoint.

[0144] 28, the connection unit 12 is disposed on the side of the terminal unit 21 opposite the display unit 20. The user can rotate the housing 15 to orient the connection unit 12 in a direction that is easy to handle.

[0145] 28, the status lamp 52 is disposed on the outer peripheral surface of the base portion 15a in the housing 15. Therefore, the status lamp 52 in Fig. 28 is provided on one end side (lower side) in the longitudinal direction A with respect to the display unit 20. Although not shown in Fig. 28, the status LED 50 of the status lamp 52 is disposed inside the sensor unit 16.

[0146] 28 includes a left key 38, a right key 37, and a center key 39 in addition to an up key 34 and a down key 35. By operating these keys, the user can easily switch the display mode of the display unit 20, and can easily change various setting values ​​in the setting mode. It is also preferable that the operation of the left key 38 has the same function as the simultaneous operation of the menu key 32 and the up key 36 in the level meter 10 in FIGS. 1 and 2.

[0147] Hereinafter, some of the screens displayed on the display unit 20 of the level gauge 10 in FIG. 28 will be described as examples of individual screens in the level gauge 10 in FIG. 1 and FIG. 2. The display unit 20 of the level gauge 10 in FIG. 28 is larger than the display unit 20 of the level gauge 10 in FIG. 1 and FIG. 2, so there is more space for display overall. FIG. 29 shows another example of the adjust mode selection screen in FIG. 14. In the adjust mode selection screen 810c in FIG. 29, a sufficient gap is secured between the interface position icon 131 and the reception intensity scale 890 and the display of the current value (here, 2800 mm) compared to the display in FIG. 14. In addition, a title bar 899 of "adjust function" is displayed at the top of the screen, indicating that this screen is a part of the adjust function 800. In addition, at the bottom of the adjust mode selection screen 810c, an option of "perform diagnosis and setting optimization" indicating the optimization mode 820 and an option of "perform learning only" indicating the limited mode 860 are displayed. The user selects one of the options by moving the cursor 810d up or down by operating the up key 34 or the down key 35. In this way, on the adjustment mode selection screen 810c in Fig. 29, the display of the options is not switched, but all of the selectable options are displayed at once.

[0148] FIG. 30 shows another example of the candidate confirmation screen of FIG. 17. In the candidate confirmation screen 822z of FIG. 30, a plurality of options (here, 1200 mm, 2000 mm, 2800 mm, empty state: 3200 mm) of the peak position (distance) of the peak candidate are displayed together on one screen in the candidate display area 895 on the right side of the screen. The user moves the cursor 895a up and down by operating the up key 34 or the down key 35 to select one of the options. Therefore, the user does not need to switch the display to check the candidate value as in FIG. 17. Although not shown in FIG. 30, the option "not applicable" may also be displayed. In this candidate confirmation screen 822z, the title bar 899 of "adjustment function" is also displayed.

[0149] Figure 31 shows another example of the optimization completion screen of Figure 22. Since there is ample display space, the optimization settings are displayed all at once on one screen without the need for scrolling as in Figure 22. This optimization completion screen also shows a title bar 899 for "Adjustment Function."

[0150] Next, a further example of the level gauge 10 will be described with reference to Fig. 32. Fig. 32 is a perspective view showing a further example of the level gauge 10. In Fig. 32, components having the same functions as those in the level gauge 10 in Figs. 1 and 28 are denoted by the same reference numerals as in Figs. 1 and 28, and descriptions thereof will not be repeated unless necessary.

[0151] 32, the level meter 10 includes a sensor unit 16 and a remote controller 55 capable of communicating with the sensor unit 16 at a position remote from the sensor unit 16. The sensor unit 16 and the remote controller 55 are connected by a communication cable 11. In the level meter 10 in FIG. 32, only the sensor unit 16 is attached to a container 70 that contains an item 72, and the remote controller 55 communicates with the sensor unit 16 at a position remote from the container 70.

[0152] As shown in FIG. 32, the sensor unit 16 has a generally cylindrical shape. The status light 52 is provided on the upper part of the sensor unit 16. The remote control unit 55 corresponds to the housing 15 in the level meter 10 of FIG. 1 and FIG. 28, and has a display unit 20 that displays according to the measured level Y. This display unit 20 can display a bar display 22 and a color gauge 24. The remote control unit 55 also has an operation unit 30 that allows the user to operate the operation of the level meter 10. The remote control unit 55 also has a connection unit 12 that serves as a connection terminal for connecting to an external device. The remote control unit 55 also has a remote status light 54. This remote status light 54 lights up in the same lighting state as the status light 52 of the sensor unit 16.

[0153] Various information is displayed on the display unit 20 of the level gauge 10 in Fig. 32, similar to the display unit 20 in the level gauge 10 in Fig. 1 and Fig. 28. The information shown to the user by the display unit 20 in Fig. 32 is the same as that in Fig. 1 and Fig. 28. The display content by the display unit 20 in Fig. 32 may be simplified depending on the size of the display unit 20.

[0154] Some of the screens displayed on the display unit 20 of the level gauge 10 in Fig. 32 will be described below as alternative examples of the individual screens in the level gauge 10 in Figs. 1 and 28. Fig. 33 is a diagram showing screen transitions on the display unit 20 of the remote controller 55 in the adjustment function 800 (Fig. 10). In the adjustment function 800, text is displayed on the display unit 20 of the remote controller 55 instead of the bar display 22 and color gauge 24. Due to display space limitations, the interface position icon 131 and reception intensity scale 890 are not displayed on the display unit 20 of the remote controller 55. Also, only one line of text is displayed.

[0155] When the adjustment function 800 is started, first, the character string "Adjustment Function" is displayed on the display unit 20. When the menu key 32 is operated in this state, a cancel screen 800a with the character string "Back" displayed is displayed on the display unit 20. When the menu key 32 is operated in this state, the adjustment function 800 is interrupted, and the display unit 20 returns to the normal measurement mode 500 as shown in FIG.

[0156] By operating the directional keys 33, the display unit 20 can transition between a cancel screen 800a, an optimization mode selection screen 810a, and a limited mode selection screen 810b. On the display unit 20 of the remote controller 55, the character string "Diagnosis & Optimization" indicates the optimization mode selection screen 810a. Also, the character string "Learning Only" indicates the limited mode selection screen 810b.

[0157] When the menu key 32 is operated on the optimization mode selection screen 810a, processing of the optimization mode 820 in Fig. 11 is started. As other examples of the screen of the display unit 20, here, other examples of the screen in the candidate selection included in the optimization mode 820 (step 822 in Fig. 11) and other examples of the screen on which the suggestion message is displayed (step 827 in Fig. 11) will be described.

[0158] Before the candidate selection in step 822 is performed, the display unit 20 displays a candidate selection message in the form of a character string "Select the correct distance". This message prompts the user to select a value that represents the correct distance of the contents 72 on the next screen. When the menu key 32 is operated in response to the candidate selection message, a second candidate confirmation screen 822b is displayed on the display unit 20. The value of the peak candidate "800 mm" is displayed on the second candidate confirmation screen 822b. The second candidate confirmation screen 822b can be transitioned to a third candidate confirmation screen 822c that displays the value of another peak candidate "1000 mm" by operating the direction key 33. In addition, although not shown in FIG. 33, the display unit 20 may be transitioned to a first candidate confirmation screen 822a that indicates that the container 70 is empty, and a fourth candidate confirmation screen 822d that displays the character string "Not Applicable" by operating the direction key 33. When the menu key 32 is operated on any of the candidate confirmation screens, the displayed peak candidate is selected as the target peak PS.

[0159] Due to display space limitations, long suggested messages cannot be displayed on the display unit 20 of the remote control device 55. Therefore, instead of a suggested message, the display unit 20 of the remote control device 55 displays a "diagnostic code" number (5-200 in this example). The diagnostic code number and the corresponding suggested message are written in a document prepared for the remote control device 55 (such as an operation manual for the remote control device 55). The user can check the content of the suggested message by comparing the displayed diagnostic code with the document.

[0160] Next, Fig. 34 is a diagram showing screen transitions on the display unit 20 of the remote controller 55 in the limited mode 860 (Fig. 13). When the menu key 32 is operated on the limited mode selection screen 810b (character string "Learning only") in Fig. 33, the limited mode 860 in Fig. 13 is started. As another example of the screen of the display unit 20, another example of the screen in the candidate selection (step 864 in Fig. 13) included in the limited mode 860 and another example of the screen displayed when learning is completed (step 867 in Fig. 13) will be described here.

[0161] In the limited mode 860, the screen display for candidate selection is the same as in the optimization mode 820 of Fig. 33. First, a candidate selection message is displayed on the display unit 20 in the form of a character string saying "Select the correct distance", and then a second candidate confirmation screen 822b, a third candidate confirmation screen 822c, and other screens to which transitions can be made are displayed, displaying multiple peak candidates. When the menu key 32 is operated on any of the candidate confirmation screens, the displayed peak candidate is selected as the target peak PS.

[0162] Even when the learning is completed, a long character string is not displayed on the display unit 20 of the remote control device 55. Therefore, when the learning is completed in the limited mode 860, only "Complete" is displayed on the display unit 20 of the remote control device 55. [Explanation of symbols]

[0163] 10 Level gauge 15. Cabinet 15a Pedestal 16 Sensor section 17 Mounting part 19 Rotation mechanism 20 Display section 21 Terminal Unit 22 Bar Display 24 Color Gauge 26 Auxiliary display 30 Control section 41 Sensor IC 43 Transmitter / receiver 43T Transmitter circuit 43R Receiver circuit 52 Status Light 61 Setting section 63 Memory section 64 Arithmetic section 65 Input section 66 Output section 70 containers 72 Contents 74 Interface 88 Measurement value determination unit 911 Distribution determination unit 912 Extraction part 913 Candidate Decision Department

Claims

1. A level meter for measuring the level of an object contained in a container, a transmitting / receiving unit including a transmitting circuit for transmitting a measurement signal for measuring the level, and a receiving circuit for receiving a reflected signal resulting from reflection of the measurement signal; a distribution determining unit that determines a distribution of the reception intensity of the reflected signal with respect to the distance from the level meter based on the reception intensity of the reflected signal received by the receiving circuit; an extracting unit that extracts a peak position and a peak intensity from the reception intensity distribution determined by the distribution determining unit; A measurement value determination unit that determines a measurement value related to the distance or the level of the contents based on the peak position extracted by the extraction unit; a candidate determination unit that extracts a plurality of combinations of the peak position and the peak intensity from the reception intensity distribution determined by the distribution determination unit using the extraction unit to determine the combinations as a plurality of peak candidates; a display unit that displays information about the measurement values ​​and the reception intensities corresponding to each of the plurality of peak candidates determined by the candidate determination unit; and A level meter equipped with

2. When any one of the plurality of peak candidates displayed on the display unit is selected as a target peak, the measurement value determination unit removes the peak candidates other than the target peak from the reception intensity distribution, and determines the distance or the level of the contained item based on the target peak to set it as the measurement value related to the contained item.

2. The level meter of claim 1.

3. The level meter of claim 2 , wherein after the target peak is selected, the display unit displays information about the measurement value and the reception intensity corresponding to the target peak as the peak candidate.

4. 3. The level meter of claim 2, wherein information about the target peak can be erased after the target peak is selected.

5. The level meter of claim 1 , wherein the display unit displays stability of the reception strength when displaying the information on the measurement values ​​and the reception strength corresponding to each of the plurality of peak candidates.

6. 2. The level meter of claim 1, wherein after the target peak is selected, a diagnosis of the measurement environment is performed based on the target peak and the reception intensity distribution, and the display unit displays a suggested message regarding the measurement environment of the level depending on the result of the diagnosis.

7. 2. The level meter of claim 1, wherein after the target peak is selected, a diagnosis regarding the measurement environment is performed based on the target peak and the reception intensity distribution, and the measurement value determination unit performs optimization of settings required to determine a measurement value regarding the distance or the level of the contained object depending on the result of the diagnosis.

8. The level meter of claim 7, wherein the measurement value determination unit optimizes settings required to determine a measurement value related to the distance or the level of the contents by applying predetermined settings corresponding to a classification of the diagnosis result.

9. 2. The level meter of claim 1, wherein the display unit displays a question regarding the measurement conditions of the level, and optimization of settings required to determine a measurement value regarding the distance or level of the contents is performed based on an answer entered to the question.

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