JP2006078368A - Ranging sensor and its setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ranging sensor capable of changing display mode flexibly and capable of changing output setting variably. <P>SOLUTION: The ranging sensor comprises: a sensor head part for irradiating a ranging object with a ranging medium and detecting the reflected ranging medium; an operation part capable of operating the distance from the irradiation surface of the sensor head part to the ranging object on the basis of the value detected by the sensor head part; a setting part for previously setting the threshold value, reference value, and plus/minus direction to the display to the reference value; a displacement display part capable of converting the measured distance operated at the operation part into the display value according to the reference value set at the setting part and to the plus/minus direction; and an output part capable of outputting the prescribed ON/OFF when the display value to be displayed on the displayable displacement display part and the display value to be displayed on the displacement display part reaches the threshold value set at the setting part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a distance measuring sensor capable of detecting and measuring the presence / absence, distance / displacement of an object, and a setting method thereof.

  Conventionally, various sensors such as a photoelectric sensor and a proximity switch have been developed. These sensors detect the presence / absence of an object (work) using light waves, sound waves, and the like, can perform ON / OFF output in accordance with the presence / absence, and are used in a wide range of applications such as FA. Sensors such as photoelectric sensors generally cannot detect displacement or distance because their main purpose is to detect the presence or absence of a workpiece. On the other hand, sensors that can measure distance and displacement, such as laser light displacement sensors, capacitive displacement sensors, and eddy current displacement sensors, have been developed. A sensor capable of measuring a distance can perform more advanced control such as determination of the posture and orientation of a workpiece and identification of a plurality of types of workpieces.

  For example, as shown in FIG. 2A, an ultrasonic sensor that uses ultrasonic waves instead of light as a distance measuring medium is ultrasonically directed toward an object (work) from an ultrasonic transmitter provided inside the sensor head unit. The ultrasonic wave is irradiated, the reflected ultrasonic wave is received by the ultrasonic receiver, and the time required until the reception is measured, and based on this, the distance between the sensor head unit and the workpiece can be detected. It is also possible to set the sensor output to be turned on when the measured value exceeds a preset threshold value.

  Such a sensor can measure and display the distance between the sensor head unit and the workpiece in addition to ON / OFF switching based on a threshold value. This display mode can be suitably used for a mode in which the distance between the workpiece and the sensor head unit is measured and displayed as shown in FIG. However, it may be inconvenient depending on the state of use only with such a display mode that only displays the measured distance. For example, when detecting the height Y of the workpiece placed on the floor as shown in FIG. 2B, the distance A between the end surface of the sensor head unit and the floor is measured in advance, and an ultrasonic sensor is used. It is necessary to determine Y by subtracting the measured distance X.

  In addition, in a sensor, a display in which a measured value increases as the distance between the sensor head portion and the workpiece increases, that is, a display that becomes + when a set value is exceeded is common. For example, as shown in FIG. 2C, when a reference position A is set in advance for measurement and the measured displacement is to be displayed as +/− from the set position A, the reference position, the sensor head portion, If there is a workpiece between the two, it is always displayed as-.

  Such a display mode may cause confusion to the user. If the user can set the information that he wants to obtain or want to know to display it directly without performing calculation or positive / negative conversion, the user can understand intuitively and intuitively just by looking at the display, and can use it conveniently.

On the other hand, the sensor is generally configured so that the output is turned on when a set value is exceeded, and is turned off when the value falls below the set value. For this reason, if it is set to be turned on when it falls below the set value, an operation with a sense of incongruity will occur if the operation is based on the threshold value of the sensor. As described above, in the conventional sensor setting, a flexible setting according to the usage mode and the user's preference cannot be performed, and the usability is poor.
JP 2003-218679 A

  The present invention has been made in view of such a current situation. An object of the present invention is to provide a distance measuring sensor capable of flexibly changing a display form and a setting method thereof. Another object of the present invention is to provide a distance measuring sensor capable of changing output settings and a setting method thereof.

  In order to achieve the above object, a distance measuring sensor according to the first aspect of the present invention includes a sensor head unit that can irradiate a target with a distance measuring medium and detect the distance measuring medium reflected by the target. A calculation unit capable of calculating a distance from the irradiation surface of the sensor head unit to an object based on a value detected by the sensor head unit, and a threshold value, a reference value, and a positive / negative direction of display with respect to the reference value in advance The measurement distance calculated by the setting unit and the calculation unit is converted into a display value according to the reference value and the positive / negative direction set by the setting unit, and the display value displayed on the displacement display unit and the displacement display unit can be displayed. An output unit that compares the threshold value set by the setting unit and can output in a predetermined ON / OFF operation pattern is provided. With this configuration, it is possible to arbitrarily set the reference value and the positive / negative direction of the distance measurement, and it is possible to display flexibly in accordance with the usage and mode of use.

  In the distance measuring sensor according to the second aspect of the present invention, the display value in the displacement display unit is a value obtained by calculating the difference between the measurement distance and the reference value according to the positive and negative directions set in the setting unit. . As a result, it is possible to directly display the value that the user wants to obtain as the display value in the displacement display section, and usability can be improved.

  Furthermore, in the distance measuring sensor according to the third aspect of the present invention, the setting unit further switches the timing at which the output unit outputs a predetermined ON / OFF to a time when the display value exceeds or falls below the threshold value. It is configured as possible. With this configuration, it is possible to set whether to output when the measured value is above or below the threshold value, so that flexible output according to the usage and mode of use is possible.

  Furthermore, the distance measuring sensor according to the fourth aspect of the present invention has a preset reference when the sensor head unit cannot detect the distance measuring medium and the distance measured exceeds the distance range that the distance measuring sensor can measure. The display value corresponding to the measured value can be displayed on the displacement display unit. Thereby, even when the distance cannot be measured due to the positional relationship between the sensor head part and the object, the display value can be obtained, and the degree of freedom of arrangement of the sensor head part can be increased.

  Furthermore, the distance measuring sensor according to the fifth aspect of the present invention is configured such that the setting unit can set the reference value outside the distance measurable by the sensor head unit.

  Furthermore, in the distance measuring sensor according to the sixth aspect of the present invention, the sensor head unit includes a transmission unit that irradiates the distance measurement medium and a reception unit that detects the distance measurement medium, and the transmission unit and the reception unit perform calculations. Controlled by the department.

  Furthermore, in the distance measuring sensor according to the seventh aspect of the present invention, the transmission unit and the reception unit are formed of the same member. Thereby, a structure can be simplified and size reduction and cost reduction are realizable.

  Furthermore, in the distance measuring sensor according to the eighth aspect of the present invention, the calculation unit is based on the time required until the distance measuring medium irradiated by the sensor head unit is detected and the traveling speed of the distance measuring medium. Thus, the distance from the irradiation surface of the sensor head unit to the object can be calculated.

  Furthermore, in the distance measuring sensor according to the ninth aspect of the present invention, the distance measuring medium is an ultrasonic wave. As a result, it is possible to perform detection with higher stability for a measurement object as compared with a photoelectric sensor or the like.

  Furthermore, in the distance measuring sensor according to the tenth aspect of the present invention, the display value in the displacement display unit is a value obtained by calculating the difference between the measurement distance and the reference value according to the positive / negative direction set in the setting unit. is there. As a result, the user can directly display a desired value on the displacement display unit without performing calculation or conversion, which can be used very conveniently.

  Furthermore, the distance measuring sensor according to the eleventh aspect of the present invention includes a sensor head unit that can irradiate an object with ultrasonic waves and detect the ultrasonic wave reflected by the object, and an ultrasonic wave irradiated by the sensor head part. Multiplying the time required until the sound wave is detected and the ultrasonic traveling speed to calculate the distance from the irradiation surface of the sensor head unit to the object as a measurement value, and the sensor head unit A setting unit for setting a position separated by a predetermined distance in the traveling direction of the sound wave as a reference position of the display value, setting a positive / negative direction of display with respect to the reference position, and setting a threshold value for the display value; The display value is calculated by adding and subtracting the measurement value calculated by the calculation unit according to the reference value and positive / negative direction set in step 1, and the display value is displayed on the displacement display unit. Was set in the settings section Upon reaching a value, and an output capable of outputting unit a predetermined ON / OFF. With this configuration, the size of the object can be calculated from the distance between the sensor head part and the object and displayed directly on the displacement display part, and the output can be turned ON / OFF by comparing the display value with a threshold value. The presence / absence detection according to the size of the object can be output in an easily understandable form.

  In addition, the distance measuring sensor setting method according to the twelfth aspect of the present invention is such that the sensor head unit irradiates the object with the distance measuring medium, detects the distance measuring medium reflected by the object, and the arithmetic unit detects the sensor. The distance from the irradiation surface of the sensor head unit to the object can be calculated based on the value detected by the head unit, and the measured distance is compared with a preset threshold value, and a predetermined ON / OFF signal is output. This is a method of setting a distance measuring sensor that can be output from the output unit. This method includes a step of setting at least one of a predetermined reference position serving as a display reference or a difference amount from a setting unit provided in the distance measuring sensor, and, if necessary, a positive / negative direction of display with respect to the reference position. A step of setting and a step of setting a threshold, and the measurement distance to the object measured by the sensor head unit is converted into a display value according to the reference position and the positive / negative direction set by the setting unit, and the display value When the value reaches the threshold set by the setting unit, a predetermined ON / OFF signal is output from the output unit. Thereby, a reference value and the positive / negative direction of ranging can be set arbitrarily, and a flexible display according to a use application and an aspect is attained.

  Furthermore, the distance measuring sensor according to the thirteenth aspect of the present invention includes a displacement display unit, and displays a value obtained by shifting the measured distance from the reference position according to the positive / negative direction set by the setting unit. The value is displayed on the displacement display section. As a result, it is possible to directly display the value that the user wants to obtain as the display value in the displacement display section, and usability can be improved.

  The distance measuring sensor and its setting method according to the present invention can measure distance and displacement while detecting the presence / absence of an object, and can switch the distance and displacement, and can determine the posture of the object and distinguish multiple types. At the same time, the display on the displacement display unit can be changed so that the value that the user wants to know is directly displayed. Thereby, the user does not have the trouble of calculating and converting from the measured distance to obtain the size of the object, and can quickly obtain necessary information, thereby greatly improving usability. Furthermore, the threshold value for switching ON / OFF can also be changed from a setting that is fixed to be turned on only when the threshold value is exceeded, to be turned on when the value is lower than the threshold value. Accordingly, it is possible to set the distance measuring sensor with improved usability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a distance measuring sensor and its setting method for embodying the technical idea of the present invention, and the present invention describes the distance measuring sensor and its setting method as follows. Not specified. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

The connection between the distance measuring sensor used in the embodiment of the present invention and a computer, a printer, an external storage device and other peripheral devices for operation, control, display, and other processing connected thereto is, for example, IEEE 1394, RS-232x, RS-422, serial connection such as USB, parallel connection, or communication via network such as 10BASE-T, 100BASE-TX, 1000BASE-T, etc. Do. The connection is not limited to a physical connection using a wire, but may be a wireless connection using a wireless LAN such as IEEE 802.1x or OFDM, radio waves such as Bluetooth, infrared rays, optical communication, or the like. Furthermore, a memory card, a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like can be used as a recording medium for exchanging data or storing settings. In this specification, the term distance measuring sensor is used to include not only a distance measuring sensor but also a distance measuring sensor system in which peripheral devices such as a computer and an external storage device are combined.
[First Embodiment]

Hereinafter, an example in which a reflective ultrasonic sensor is used as a distance measuring unit will be described as a distance measuring sensor according to the first embodiment of the present invention with reference to FIGS. In these drawings, FIG. 3 is a perspective view showing an external appearance of the ultrasonic sensor 100, and FIG. 4 is a block diagram showing the sensor head unit 10 and the amplifier unit 20, respectively.
(Sensor head unit 10)

As shown in FIG. 4, the ultrasonic sensor 100 includes a sensor head unit 10 that irradiates a workpiece W with ultrasonic waves, and an amplifier unit 20 that controls the sensor head unit 10. The sensor head unit 10 includes a transmission / reception element 13 as a transmission unit for irradiating the workpiece W with ultrasonic waves as a distance measuring medium and a reception unit for receiving ultrasonic waves reflected by the workpiece W. In the ultrasonic sensor 100 shown in FIG. 4, one ultrasonic transducer is used for both transmission and reception as the transmission / reception element 13. In this example, one transducer is used alternately with time division for transmission and reception. With this configuration, the sensor head portion can be reduced in size and space can be saved. However, a transmitting ultrasonic transducer may be separately prepared as a transmitting element, and a receiving ultrasonic transducer may be separately prepared as a receiving element. The transmission / reception element is connected to a transmission circuit 14 for driving and generating and transmitting an ultrasonic wave, and a reception circuit 15 for converting an ultrasonic signal reflected by the work W and received by the transmission / reception element into an electrical signal. is doing.
(Amplifier unit 20)

Further, the amplifier unit 20 inputs a zero shift signal and a bank switching signal that the user wants to zero at a certain timing, and outputs to the transmission circuit 14 the timing of transmitting the ultrasonic wave by the input unit 22 and the transmission / reception element 13 that are output to the calculation unit 24. The ultrasonic wave that is output and transmitted by the transmission / reception element 13 at the transmission timing from the transmission circuit 14 is similarly received by the transmission / reception element 13 and input as a reception signal via the reception circuit 15, and the transmission / reception element 13 from the timing when transmission is started. The time required until the timing received at the time is counted, the calculation unit 24 that calculates the distance by adding the time and the ultrasonic velocity, the setting unit 26 for the user to perform various settings, the setting of the setting unit 26 A display unit 30 for confirming the contents and displaying the measured distance, and an output unit for outputting an output signal such as an ON / OFF signal to the outside Equipped with a 8. The arithmetic unit 24 measures the time by counting the timing received from the input unit 22 with a counter or the like. The output unit 28 compares the display value with the threshold set by the setting unit 26 and outputs an ON / OFF signal. For example, a constant voltage is output when the output is ON, and the output is 0 when the output is OFF. In the following example, the output unit 28 includes two independent systems of output 1 and output 2 as output terminals, and also includes input / output terminals whose functions can be selected according to applications as will be described later.
(Display unit 30)

As shown in the perspective view of FIG. 3, the sensor head unit 10 and the amplifier unit 20 are electrically connected by a cable unit 16. The amplifier unit 20 is provided with a display unit 30 and a setting unit 26 on the front. In the example of FIG. 3, the display unit 30 includes a first display area 32 and a second display area 34, each adopting a 7-segment display. By providing a plurality of display areas, each value can be confirmed on one screen, such as displaying a measured value in the first display area 32 and a threshold value in the second display area 34, and the current state can be displayed to the user at a glance. An interface can be realized. An output display unit 36 is provided on the left side of the first display area 32. The output display unit 36 displays the output state of the output unit 28. In the example of FIG. 3, an LED indicator is provided as the output display unit 36 for each of output 1 (OUT1) and output 2 (OUT2). A channel indicator 38 is provided on the left side of the second display area 34, and a sub-indicator 39 is provided on the right side. The channel indicator 38 indicates, for example, which of the channels 1 and 2 corresponding to the two threshold values is displayed in the second display area 34. The sub-indicator 39 functions as a warning indicator lamp.
(Setting part 26)

  The setting unit 26 is an input member for a user to perform various settings such as a threshold value, a reference value, a reference position, and a positive / negative direction. The setting unit shown in FIG. 3 determines, as input members, a mode switching unit 27 that can switch between a display mode for displaying a display value and a setting mode for setting, an increase / decrease unit 42 for specifying a set value, and a specification. A determination unit 44 is provided. Here, a mode button is provided as the mode switching unit 27, an up / down button as the increase / decrease unit 42, and a set button as the determination unit 44. Buttons, switches, dials, keyboards, touch panels, mice, slide pads, etc. can be used as input members. Needless to say, the layout and design of these display units and setting units are examples, and can be changed as appropriate. For example, the display unit and the setting unit may be integrated by a touch panel type, or the setting unit may be configured separately such as a remote controller or a console. The display unit can be a liquid crystal display. In the above example, the sensor head unit and the amplifier unit are individually configured. However, it goes without saying that a structure in which these are integrated can also be adopted. Furthermore, in the example of FIG. 4, the mode switching unit 27 is incorporated in the setting unit 26, but it goes without saying that the mode switching unit may be provided as a member separate from the setting unit.

In this specification, the setting in the setting unit means that the user inputs a desired setting value by himself / herself, automatically sets a recommended value prepared in advance, or automatically calculates from other setting items. It is used in the meaning including the case where it is set on the distance measuring sensor side such as
(Procedure for measuring distance)

  Hereinafter, a procedure for measuring the distance by the ultrasonic sensor will be described based on the ultrasonic sensor of FIG. The transmitting element uses an ultrasonic transducer. The ultrasonic vibrator has a characteristic of vibrating at a frequency when an AC voltage is applied. This vibration vibrates the air and generates ultrasonic waves. On the other hand, the ultrasonic vibrator has a reverse characteristic that a voltage is generated when vibration is applied.

The ultrasonic sensor applies an alternating voltage generated by the transmission circuit 14 to the ultrasonic transducer. The ultrasonic transducer irradiates ultrasonic waves from the sensor head unit 10 toward the workpiece W. The ultrasonic wave is irradiated for a short time, and then the transmission is stopped. While the transmission of the ultrasonic wave is stopped, the standby state is waited for the transmitted ultrasonic wave to be reflected and arrived. On the other hand, the timing from when the ultrasonic wave is transmitted until it is received is counted. When the ultrasonic vibrator is vibrated by the reflected wave of the ultrasonic wave, a voltage is generated and detected by the receiving circuit 15. The calculation unit 24 measures the time from transmission to reception of ultrasonic waves, and calculates the distance from the sensor head unit 10 to the workpiece W by multiplying the ultrasonic traveling speed, that is, the sound speed. The calculated distance measurement value is displayed on the display unit 30.
(Mode switching unit 27)

The setting unit 26 sets a display mode displayed on the display unit 30. Here, it is possible to set a reference value serving as a reference for the display mode and to set the positive / negative of the measured distance with respect to the reference value. Specifically, a normal display mode in which the measured distance is displayed on the display unit 30 as it is as shown in FIG. 5, and a conversion in which the distance from the reference position is measured based on the measured distance as shown in FIG. The display mode can be switched. The display mode is switched by switching from the display mode to the setting mode by the mode switching unit 27 as described later.
(Normal display mode)

  In the normal display mode, the distance between the sensor head unit 10 and the workpiece W is displayed on the display unit 30 as a display value. In the normal display mode, the irradiation position of the sensor head unit 10 is set to 0 as the reference position, and the direction in which the ultrasonic wave is irradiated from the sensor head unit 10 is set to be positive as the positive / negative direction. Thereby, the distance between the sensor head part 10 and the workpiece | work W can be measured, and the measured distance (measured value) can be displayed on the display part 30 as a display value as it is.

However, in this setting, when it is desired to measure the height from the background (wall surface) to the workpiece W as shown in FIG. 6, the distance A between the sensor head unit 10 and the floor surface is measured in advance, and the workpiece W and the sensor are measured. After measuring the distance X of the head unit 10, the user needs to subtract (A−X) = Y from the height Y of the workpiece W. In such a case, it is convenient if the height of the workpiece W can be calculated on the distance measuring sensor side and displayed directly on the display unit 30. Similarly, it is convenient if the threshold value can be set not only to be turned on when the threshold value is exceeded but also to be turned on when the threshold value is lowered. For this reason, a conversion display mode in which such distance conversion is automatically performed and displayed as a display value is prepared.
(Conversion display mode)

In the conversion display mode, the measurement value is converted into a desired display value by performing a predetermined calculation. Specifically, two settings are performed: a reference position, that is, an origin in measurement, and a distance measurement direction, that is, a positive / negative value of a display value displayed on the display unit 30 is set. The setting method will be described below.
(Setting the reference position)

The distance measuring sensor can set an arbitrary position as a reference position. In the normal display mode, the reference position is set so that the irradiation position of the sensor head unit 10 becomes 0 as shown in FIG. From this state, for example, the reference position can be changed so that the floor surface becomes 0 as shown in FIG. In the example of FIG. 6, a value corresponding to the distance A from the sensor head unit 10 to the floor surface is set as a reference value, and the reference position is shifted by the reference value. As a result, the height of the workpiece W can be directly displayed on the display unit 30. The setting is changed from the setting unit 26. A specific change procedure will be described later. In the above example, the reference value is set by inputting a displacement amount. However, the reference position can be specified instead of or in addition to the displacement amount. The reference position is position information and is specified by a numerical value or coordinates.
(Positive / negative direction setting)

Only by changing the reference position, the height Y of the workpiece W is displayed as a negative value. Therefore, the positive / negative direction can be changed to reverse the positive / negative. The positive / negative direction indicates the direction in which the distance is measured. In the initial setting, as shown in FIG. 5, the positive / negative direction is set to be positive in the direction in which ultrasonic waves are emitted from the sensor head unit 10 and negative in the reverse direction. . On the contrary, the positive / negative direction can be changed so that the direction in which ultrasonic waves are emitted from the sensor head unit 10 becomes negative. FIG. 6 shows a state in which the positive and negative directions are set in the opposite direction to FIG. In the example of FIG. 6, as a result of changing the reference position and the positive / negative direction, the distance is measured in the direction from the floor surface toward the sensor head unit 10. That is, a value Y obtained by subtracting the distance X between the workpiece W and the sensor head unit 10 as a measured value from the distance A between the floor surface set as the reference position and the sensor head unit 10, that is, the height of the workpiece W is used as the display value. It is displayed on the display unit 30.
(Outside measurement range)

  Further, by shifting the reference position, distance measurement can be performed even if the distance measuring sensor is placed outside the measurement range. For example, as shown in FIG. 7, when there is no work, consider an example in which the distance measuring sensor is arranged at a position outside the distance measurement range. In the case of FIG. 7A, since there is no work, the ultrasonic wave irradiated from the sensor head unit 10 is not reflected, and the distance cannot be measured due to infinity. Even in this case, the display value “0” can be displayed by setting the position corresponding to the edge of the workpiece W as the reference position. That is, in the example of FIG. 7, if the distance from the sensor head unit 10 to the edge of the workpiece W is A, the display value on the display unit 30 can be zero with the measured value A. Further, when the workpiece W exists as shown in FIG. 7B, the height Y1 of the workpiece W can be measured and displayed. In the example of FIG. 7B, the workpiece W exists on the side closer to the sensor head unit 10 from the reference position. In order to display the height Y1 of the workpiece W as a positive value in this state, the positive / negative direction is set to be opposite, that is, the direction in which the reflected ultrasonic wave is directed to the sensor head unit 10 is set to be positive. As a result, the display value can be displayed even in a state where measurement is not possible as shown in FIG. 7A, and the height Y1 of the workpiece W can be appropriately displayed when the workpiece W exists.

  On the other hand, as shown in FIG. 7C, when the workpiece W passes through a position away from the sensor head unit 10 with respect to the reference position, the direction in which the ultrasonic wave is irradiated from the sensor head unit 10 in the positive / negative direction. By setting to be positive, the height Y2 of the workpiece W can be measured and displayed. In any case, it is possible to determine whether the workpiece W passes through the right or left of the reference position based on whether the display value displayed on the display unit 30 is positive or negative.

In the above example, the reference value is set within the measurement limit of the distance measuring sensor, but the reference value can also be set at a position outside the measurement limit of the distance measuring sensor as shown in FIG. In the example of FIG. 8, as in FIG. 7, when the reflection of ultrasonic waves cannot be detected in the absence of the workpiece W, the display value is calculated assuming that the reference value has been measured. In the example of FIG. 8A, 0 is the display value as a value obtained by subtracting the reference value from the measured value (referred to as a reference value). In the state in which the workpiece W is arranged as shown in FIG. 8B, Y corresponding to the height of the workpiece W is displayed on the displacement display unit 30 as a display value as a value obtained by subtracting the measurement value X from the reference value. The
(Invert output)

The setting unit 26 can also perform setting for reversing output ON / OFF. For example, an output pattern that is turned on when the threshold value is exceeded may be changed to an output pattern that is turned on when the value is lower than the threshold value (inverted output). As a result, detailed setting changes according to the use conditions are possible. The output pattern change unit 25 changes the output pattern according to the setting of the setting unit 26.
(Automatic output pattern switching)

By the way, in the general sensor output, the threshold value is set in advance in an intermediate region between the measured value when there is a workpiece and the measured value when there is no workpiece, and an ON signal is output when the measured value exceeds the threshold value. To control. However, when the threshold value is set in the arrangement of FIG. 1, when the workpiece W is detected, the measured value falls below the threshold value and the output is OFF. When there is no workpiece W, the measured value exceeds the threshold value and the output is ON. The output ON / OFF pattern is reversed. Therefore, in the present embodiment, in the normal display mode, as shown in FIG. 5, the circuit logic of the output unit 28 in the output pattern changing unit 25 is set so that the output is ON when it is below the threshold value and the output is OFF when it is above the threshold value. Automatically change.
(Output pattern changing unit 25)

  The output pattern changing unit 25 changes the circuit logic according to the detection mode with different display and output patterns set by the setting unit 26, and the output is ON when there is a work in any detection mode, and when the output is not present The output pattern is adjusted so that the output is turned off.

  In the example of FIG. 4, the output pattern changing unit 25 is incorporated in the calculating unit 24, and the setting unit 26 detects that the detection mode is set to the normal display mode by the output pattern changing unit 25 of the calculating unit 24. The circuit logic of the output unit 28 is changed. However, this configuration is merely an example, and it is needless to say that the output pattern changing unit can be provided as a separate member from the calculation unit. In addition to automatically changing the output pattern according to the detection mode, the user can also change the output pattern manually from the setting unit 26.

  The output pattern changing unit 25 changes the circuit logic of the output unit 28 so that the output is turned on when the display value is smaller than the threshold value, and the output is turned off when the display value is larger. As such circuit logic, for example, there is a normal close (NC) or a break in which the relay of the output unit 28 is closed at the normal position, that is, ON.

On the other hand, in the operation in the conversion display mode, as shown in FIG. 6, the threshold value is set to an intermediate area of the measurement value when the workpiece W is present. In this case, since the display value is converted from the distance between the sensor head unit 10 and the workpiece W to the height of the workpiece W, the display value exceeds the threshold when the workpiece W is present, and falls below the threshold when there is no workpiece W. . Since this operation matches the output pattern of a normal sensor, there is no need to change the output pattern. Therefore, when the output pattern changing unit 25 detects that the conversion display mode is selected by the mode switching unit 27, the output is turned on when the circuit logic exceeds the normal output pattern, that is, the threshold value is exceeded, and the output is turned off when the circuit logic is lower. Set. As this circuit logic, for example, there is a normal open (NO) or make-up in which the relay of the output unit 28 is in the open position, that is, OFF at the normal position, and is ON when there is a trigger.
(Threshold setting change)

  In the above example, the output pattern changing unit 25 changes the circuit logic between the normal display mode and the conversion display mode, so that the output pattern is output ON when a workpiece is detected, and output OFF when the workpiece is not detected. Realized. However, by changing the setting position of the threshold value instead of changing the output pattern, the output pattern is turned on when the threshold value is exceeded and turned off when the threshold value is not exceeded. If there is no output, it is possible to realize an output that is OFF. That is, in the example of FIGS. 5 and 6, in both the normal display mode and the conversion display mode, the threshold value is set between the workpiece W and the wall surface. The relationship was reversed. On the other hand, as shown in FIG. 9, in the normal display mode, by changing the position where the threshold is set between the workpiece and the sensor head unit, the measured value can be larger than the threshold when there is a workpiece. . That is, the output can be turned on when the measured value is larger than the threshold value, and can be matched with the general output pattern of the sensor in which the workpiece is detected when the measured value exceeds the threshold value. With this setting, when there is no workpiece, the measured value is smaller than the threshold value, so the output is also turned off. On the other hand, in the conversion display mode, as shown in FIG. 10, a threshold value is set between the workpiece and the background, that is, a threshold value is set between the case where there is a workpiece and the case where there is no workpiece. (Work height) is less than the threshold value and the output is OFF. When there is a work, the display value is equal to or more than the threshold value and the output pattern of output ON can be maintained. With this method, the output pattern of the sensor can be maintained as usual regardless of the normal display mode and the conversion display mode without changing the circuit logic by the output pattern changing unit.

In this way, by changing the threshold position, that is, the threshold value, it is possible to match the presence / absence of the workpiece and the output ON / OFF without changing the output pattern of the output unit. The threshold value can be set automatically by the user by manually inputting numerical values from the setting unit 26. The function of automatically setting the threshold value is called auto tuning. By auto-tuning, the calculation unit 24 automatically calculates and sets the threshold value from the position of the workpiece. For example, in the example of FIG. 9, the arithmetic unit uses the measurement distance (500 mm in the example of FIG. 9) when the workpiece exists and the intermediate (250 mm) between the measurement distance (0 mm in the example of FIG. 9) when there is no workpiece as a threshold. 24 is set automatically.
(Auto tuning)

Auto-tuning is a function for automatically adjusting the sensitivity of the sensor head section or setting a threshold value, and is usually performed at the time of initial setting such as changeover of a distance measuring sensor. In the present embodiment, five points of two-point tuning, maximum sensitivity tuning, full-auto tuning, one-point zone tuning, and conveyor tuning can be selected and executed as auto-tuning. Various tunings are selected and executed by operating the setting unit 26. Hereinafter, each tuning will be described.
(Two-point tuning)

  In the two-point tuning, a state where there is a workpiece and a state where there is no workpiece are stored. The distance measuring sensor obtains an optimum threshold value from distance information in a state where there is a work, according to whether the current display mode is the normal display mode or the conversion display mode. In the normal display mode, the distance when there is no workpiece is regarded as the maximum detection range distance, and a threshold is provided between the distance when the workpiece is present and the maximum detection range distance. Hereinafter, the two-point tuning procedure in the normal display mode will be described with reference to FIG. First, two-point tuning is started by an operation of the setting unit 26 or external input, one work is placed at the ultrasonic irradiation position of the distance measuring sensor, and the set button is pressed once. Then, as shown on the right side of FIG. 11, “SEt” indicating that the two-point tuning is being set is displayed in the second display area 34, and the measured value (distance to the workpiece) is displayed in the first display area 32. Is displayed. Next, when the set button is pressed once without a work, the value set as the threshold is displayed.

On the other hand, in the conversion display mode, the distance when there is no work is regarded as 0, and a threshold value is set between the distance (display value) when the work is present and 0. The procedure is the same as in FIG. 11 described above, and is set to 250 mm which is an intermediate between 0 and the workpiece height of 500 mm as shown in FIG. 10 by two-point tuning. In this way, in both the normal display mode and the conversion display mode, the user can set the threshold automatically only by actually placing the workpiece on the distance measuring sensor, which eliminates the need for calculations and numerical input, and is extremely simple. Can be used for This two-point tuning can be used in the independent detection mode described later.
(Maximum sensitivity tuning)

The maximum sensitivity tuning is a tuning for detecting all the workpieces by setting to the minimum set value that is not turned ON and detected during tuning. For example, when the maximum sensitivity tuning is performed in the background state, the minimum value that does not detect the background, that is, the maximum sensitivity is set. To perform the maximum sensitivity tuning, press the set button for 3 seconds or more with no work, confirm that “SEt” is blinking in the second display area 34, and release the set button. Accordingly, a value that is slightly smaller than the maximum distance that can be detected by the distance measuring sensor is set as a threshold value by the calculation unit 24. An example of performing maximum sensitivity tuning in the normal display mode is shown in FIG. In this example, 900 mm is set as the threshold value with respect to 1000 mm, which is the maximum range detectable by the sensor head unit. On the other hand, in the conversion display mode, a value slightly larger than 0 is set as the threshold value. In the example of the maximum sensitivity tuning in the conversion display mode shown in FIG. 13, 100 mm is set as the threshold value. Thus, the threshold value is set to a value of several percent to several tens percent with respect to the reference value. This maximum sensitivity tuning can also be used in the independent detection mode described later.
(Full auto tuning)

In full auto tuning, the threshold is automatically set by actually moving the workpiece such as flowing the workpiece on the line. An example of full auto tuning is shown in FIG. As shown in this figure, the work is run while the set button is pressed, and “SEt” blinks in the second display area 34, that is, confirms that the threshold value has been acquired. Release. Thereby, an optimal threshold value is set according to the normal display mode and the conversion display mode. This full auto tuning can be used in the independent detection mode.
(One-point zone tuning)

One-point zone tuning can be used in a height discrimination mode shown in FIG. 18 described later, and an appropriate threshold is set when there is a background such as a conveyor in the detection range. To perform one-point zone tuning, place the workpiece at the ultrasonic irradiation position of the distance measuring sensor and press the set button once. That is, the distance from the workpiece detected while the set button is pressed is set as the set value. By setting the deviation (HL) to this, only the workpiece used for tuning can be detected.
(Conveyor tuning)

The conveyor tuning can be used in the background fluctuation detection mode, and can be used when the background distance of the conveyor or the like changes. FIG. 15 shows an example in which conveyor tuning is performed. In this way, the conveyor is first operated without a workpiece, and the set button is pressed once. Then, after operating the conveyor for a while, when the set button is pressed once, the vertical fluctuation amount of the conveyor is detected, the reference position is determined in consideration of this displacement amount, and an appropriate threshold value can be set.
(Detection mode)

The distance measuring sensor according to the present embodiment includes the following five detection modes with different display and output patterns.
(1) Independent detection mode in which the measured value is displayed as a value with a preset reference value as a scale, and the output can be turned ON / OFF depending on the magnitude of the displayed value and a preset threshold value (2) The measured value Is displayed with a value that uses a preset reference value as a scale, and a height discrimination mode in which output can be turned ON / OFF depending on whether or not this display value is in the vicinity of a preset threshold value (3) Provided with an output, the measured value is displayed as a scale with a preset reference value as a scale, and when the displayed value exceeds a preset threshold, one output can be turned ON / OFF, and Background change detection mode in which output can be turned ON / OFF when other output falls below another preset threshold (4) Designate one area in advance and designate another spare area including that area Depending on which area the display value is included in, ON / O of output Liquid level window mode capable of F (5) Two or more outputs are provided, and two threshold values are set in advance, one output is turned ON / OFF at one threshold value, and the other output is set to a reverse output pattern. Zone control mode in which the other output is turned ON / OFF at the other threshold and one output is reversed.

One of the detection modes is selected in a setting mode to be described later, and further details are set for each detection mode. Of the above detection modes, the independent detection mode and height discrimination mode are general-purpose detection modes. The background fluctuation detection mode, liquid level window mode, and zone control mode are specific applications such as conveyor transport work detection and liquid level management. This is a detection mode specialized in Hereinafter, each detection mode will be described with reference to FIGS. In the following example, a case where two or more threshold values are set for two outputs is basically described.
(Independent detection mode)

  The independent detection mode is a detection mode in which a predetermined calculation is performed based on the measured distance to perform conversion and display, and is suitable for workpiece height detection and the like. This detection mode can be switched between the normal display mode and the conversion display mode described above. In the normal display mode, as shown in FIG. 1, the measurement value obtained by measuring the distance between the sensor head unit 10 and the workpiece W by the calculation unit 24 is displayed as a display value on the displacement display unit. In the conversion display mode, for example, as shown in FIG. 17, when detecting the presence / absence of the workpiece W conveyed on the conveyor C, the detection criterion is mainly the height of the workpiece W. In this case, it is easy to understand if the state where there is no workpiece W on the conveyor C is displayed as 0 and the state where the workpiece W is present is displayed at the height of the workpiece W on the conveyor C. To achieve this, if the distance measurement reference position is the distance between the sensor head unit 10 and the conveyor C and this point is set to 0, the positive / negative direction of distance measurement is set so that the side closer to the sensor head unit 10 is positive. The display value displayed on the display unit can be the workpiece height. Furthermore, if the threshold is set to a value slightly lower than the height of the workpiece W to be detected, the presence / absence of the workpiece can be detected.

  The output pattern of the output unit 28 in the independent detection mode is shown in FIG. In the independent detection mode, when the display value is compared with the threshold and the threshold is exceeded, the output is turned ON. In the example of FIG. 16, when two threshold values P1 and P2 are set and the output 1 and the output 2 are used as the two output units 28, the output 1 is turned ON when the threshold value P1 is exceeded, and the output exceeds the threshold value P2. ON when In this way, the outputs are not affected by each other, and perform independent ON / OFF operations.

  Further, in this example, hysteresis (Hys) is set, and the output 1 is not immediately turned OFF when the value falls below the threshold value P1, and the output is turned OFF when the output is lowered by the hysteresis set to the threshold value P1. Similarly, the output 2 is also turned off when it falls below the threshold 2 by the hysteresis set with respect to the threshold P2.

  Thus, in the independent detection mode, two arbitrary threshold values can be set and output independently. In this example, the output 1 is turned ON when the display value exceeds the threshold value P1, and turned OFF when the display value falls below the hysteresis amount set for P1. On the other hand, the output 2 (white line) turns ON when the display value exceeds the threshold value P2, and turns OFF when the display value falls below the hysteresis amount set for P2.

In the example of FIG. 16, the case where threshold values are set for two outputs has been described, but only one output can be used or three or more can be used depending on the number of outputs connectable to the distance measuring sensor. Needless to say. Further, it is possible to use the output pattern with the output pattern reversed ON / OFF.
(Height discrimination mode)

  On the other hand, the height discrimination mode discriminates whether or not the display value is a value near the threshold value. The height discrimination mode is a mode suitable for detection with a background in the detection range. That is, the height of the workpiece can be displayed as the display value with the background as the reference (0). In this mode, only a workpiece having a certain height is detected, and it is not detected whether the workpiece is too high or too low. Therefore, as shown in FIG. If thresholds corresponding to a plurality of workpiece heights to be discriminated are set as shown in this figure, the height of the workpiece W existing on the background such as the conveyor C or the desk can be directly read as a display value, and a numerical value, that is, a height Since the output is turned on, the workpiece W having a height corresponding to the threshold can be detected. In this mode, a window comparator output operation is performed such that the window comparator is turned on when it is within the deviation range with the threshold at the center. Deviation can be set as hysteresis.

  An example of the threshold value and the output pattern in the height discrimination mode is shown in FIG. As shown in this figure, when thresholds P1 and P2 are set for output 1 and output 2, respectively, hysteresis is set around the threshold P1, and each output is turned on when it is within this range. Thus, two arbitrary threshold values can be set and output independently in the height discrimination mode. The output 1 shown in FIG. 19 is turned OFF when the display value deviates from the threshold value P1 by a preset hysteresis or more. When the display value falls within the preset hysteresis range from P1, it is turned on again. On the other hand, the output 2 is turned OFF when the display value deviates from the threshold value P2 by a predetermined hysteresis or more. When the display value falls within the preset hysteresis range from P2, it is turned on again.

The difference between the height discrimination mode and the independent detection mode is that the independent detection mode basically switches ON / OFF depending on whether the display value exceeds the threshold value or not, whereas the height discrimination mode has the display value of the threshold value. ON / OFF is determined by whether or not it is in the vicinity. As apparent from FIGS. 16 and 19, in the independent detection mode, the hysteresis is set only on the lower side of the threshold because the output is OFF, whereas in the height determination mode, the threshold is set on both the upper and lower sides of the threshold.
(Tuning height discrimination mode)

As described above, the tuning in the height discrimination mode is one-point tuning, and the median value of data sampled while the set button is pressed is set as the tuned threshold value. When the height discrimination mode is selected, the detection reference setting is automatically turned ON.
(Background fluctuation detection mode)

  The background fluctuation detection mode is a detection mode that can cope with a case where the position of the object fluctuates. For example, as shown in FIG. 20, a workpiece W conveyed by a belt conveyor or the like swings up and down due to the deflection of the belt conveyor. In such a case, a fluctuation amount that swings in the measurement direction, such as up and down, is stored in advance, and a setting value that does not turn ON with this fluctuation amount is automatically set. Here, the height of the workpiece W is displayed with the conveyor C as a reference (0).

An output pattern in the background fluctuation detection mode will be described with reference to FIG. In the background fluctuation detection mode, the threshold value P1 is set so that the output 1 is turned on when a workpiece W higher than the conveyor C comes without detecting the conveyor C. As a result, the output 1 can be used as a comparison output for the workpiece height. On the other hand, the output 2 is a predictive maintenance output regarding the state of the conveyor C, and can be used for detection of an abnormality such as the position of the distance measuring sensor and the conveyor being shifted or the conveyor being cut. For example, by setting the threshold value P2 to a value of −P1, the threshold value P1 becomes the detection setting value from the detection reference position, and the threshold value P2 becomes the maintenance output setting value. As a result, as shown in FIG. 21, the output 1 is turned ON when the display value exceeds the threshold value P1, and turned OFF when the display value falls below the hysteresis amount set with respect to P1. On the other hand, the output 2 is turned on when the display value exceeds the threshold value P2, and turned off when the display value falls below the set hysteresis amount with respect to P2.
(Background fluctuation detection mode tuning)

  The tuning of the background fluctuation detection mode is performed by the conveyor tuning as described above, so that the user can automatically correct the fluctuation amount of the conveyor and realize accurate detection. In the conveyor tuning, display value data while the set button is being pressed is sampled by the calculation unit 24, and the runout width and the median distance are obtained. Then, as shown in FIG. 20, a value obtained by adding a margin for workpiece detection to the up and down swing width of the conveyor is set as a threshold value 1. On the other hand, the median of the runout width of the conveyor is set to the threshold value 2. As a result, a detection reference is set such that the position of the conveyor where no workpiece is flowing is set to 0, and a threshold value for stably detecting the workpiece flowing on the conveyor C is determined. When the conveyor tuning is performed in this way, the threshold value P1 is automatically set so that the output 1 is turned on when a workpiece W higher than the conveyor C comes without detecting the conveyor C. In the example of FIG. 20, the threshold value P2 is automatically set to a value of -P1.

When the background fluctuation detection mode is selected, the detection reference setting is automatically turned ON. When this mode is selected, the external shift / bank switching function cannot be selected. Further, the output 2 is automatically switched to normal close so that it becomes an inverted output.
(Liquid level window mode)

  In the liquid level window mode, the output can be changed depending on which area the display value is in by specifying the area and specifying the spare area outside the area. This detection mode is a mode suitable for level detection such as detection of the liquid level in the tank. For example, in the liquid level management as shown in FIG. 22, the height of the liquid level is set with the bottom of the tank as a reference (0). Set as display value. In this case, in addition to the upper and lower thresholds, two thresholds for the prediction signal before the upper and lower limits can be set, and the two outputs can be turned ON / OFF according to the total of four thresholds. Here, a case is considered in which P2 and P3 are set as upper and lower thresholds, and control is performed so as to maintain the liquid level in the range of P2 to P3. By setting the spare areas P1 and P4 outside this area, it is possible to determine which spare area is outside the control range and outside the range beyond the spare area. Control becomes possible. In the example of FIG. 22, P2 is set to 80, P3 is set to 60, the spare area P1 is set to 100, and P4 is set to 40. With these values, the outputs OUT1 and OUT2 are output as shown in the left of FIG. The areas A, B, C, D, and A can be distinguished by the combination. The amplifier section has two output display sections OUT1 and OUT2 as shown in FIG. 3, and the four states are distinguished as shown in the table on the left side of FIG. 22 by the combination of ON / OFF of these two output lamps. it can.

FIG. 23 illustrates output patterns 1 and 2 in the liquid level window mode. In this figure, the threshold P1 is Hi-Hi, the threshold P2 is Hi, the threshold P3 is Lo, and the threshold P4 is Lo-Lo. Thus, Hi-Go-Lo output is realized with two outputs in the liquid level window mode. Furthermore, the hysteresis setting is added to the lower side for Hi-Hi and Hi, and to the upper side for Lo and Lo-Lo. Here, when the display value increases, the output 1 is turned ON when it exceeds the hysteresis amount set from the threshold value P4. When the threshold value P1 is exceeded, it is turned OFF. When the display value decreases, the display value is turned on when the hysteresis value falls below the threshold value P1. Moreover, it will turn OFF when it falls below the threshold value P4. On the other hand, when the display value increases, the output 2 is turned on when it exceeds the threshold value P2 by a set hysteresis amount. Also, when the threshold value P3 is exceeded, it is turned OFF. When the display value decreases, the display value is turned on when the hysteresis value falls below the threshold value P3, and turned off when the display value falls below the threshold value P2. When the liquid level window mode is selected, the detection reference setting is automatically set to ON. The input / output terminals automatically become analog outputs.
(Zone control mode)

  The zone control mode is a detection mode in which two threshold values are set to specify an area and the output at each threshold value is inverted. This detection mode is literally a mode suitable for liquid level management and the like. In particular, a single distance measuring sensor detects the liquid level in the tank and performs pump control to maintain the liquid level within the upper and lower limits. Can be suitably used. For example, as shown in FIG. 24, the water level of the liquid level stored in the tank is measured by a distance measuring sensor, and the water level is maintained in the range of P1 to P2 by operating either the liquid supply pump or the drain valve. Consider an example of control. Here, the water level of the liquid level can be directly displayed on the displacement display unit by setting the level of the liquid level as a display value with the tank bottom as the reference (0). Also, two upper and lower threshold values P1 and P2 that divide the range are set.

  FIG. 25 shows output patterns of outputs 1 and 2 in the zone control mode. As shown in this figure, the output 1 is turned off when the display value exceeds the upper limit threshold value P1. Turns on when the display value falls below the lower threshold P2. On the other hand, the output 2 is turned on when the display value exceeds the upper limit threshold value P1, and turned off when the display value falls below the lower limit threshold value P2. Thus, the output 1 is turned ON when the detected liquid level falls below the lower limit threshold P2, and the output 1 is turned OFF when the detected liquid level exceeds the upper limit threshold P1. Thus, the liquid level control is realized by setting the output 1 as the operation of the liquid supply pump or the output 2 as the operation of the drain valve. In particular, output 2 can be connected to either the supply side (output 1) to the tank or the discharge side (output 2) from the tank by switching the output 1 to the inverted output. Can be realized. Accordingly, when the water level exceeds P1, the drain valve is opened to control to lower the water level, or when the water level falls below P2, the liquid supply pump can be operated to increase the water level.

The zone control mode described above can be used for various purposes regardless of its name. For example, the present invention can be applied to tension control as shown in FIG. In FIG. 26, the tension of the belt supported by the left and right rollers driven by the motor is controlled within a predetermined range from the lower surface of the belt by the distance measuring sensor. In this example, since the rotation operation of the motor is reversed on the left and right, uniform tension control can be realized from the left and right by setting the outputs 1 and 2 of the zone control mode as the motor operation. As described above, the names in the above-described detection modes are not limited, and it goes without saying that each detection mode can be appropriately used for applications to which each output pattern can be applied regardless of the name. The zone control mode corresponds to bank input, and automatically operates with detection reference setting ON. In this example, two threshold values are set. Needless to say, three or more threshold values can be set.
(Details of setting method)

Each detection mode is selected and set by using the setting unit 26 and the displacement display unit provided in the amplifier unit shown in FIG. The displacement display unit has a display mode for displaying a display value during operation in the selected detection mode and a setting mode for setting each detection mode, and these are switched and displayed. Hereinafter, details of the display mode and the setting mode will be described.
(Display mode)

  FIG. 27 shows a state transition diagram in the display mode. In the display mode, the display value set in the setting mode described later is displayed. In the example of FIG. 27, as shown in (a), the display value is displayed in the first display area 32 of the displacement display section, and the threshold value is displayed in the second display area 34. Two or more threshold values can be set. In this case, to switch the display of the threshold value, when either the mode button or the up / down switch is pressed, another threshold value is displayed in the second display area 34 as shown in FIG.

  Furthermore, the display value can be switched to a peak / bottom hold display in which the maximum value (peak) and the minimum value (bottom) of values measured in the past are held and displayed. In the example of FIG. 27, when the mode button is pressed from the state of (a), the display is switched to the peak / bottom hold display, and the “HLd” display indicating the peak / bottom hold display as shown in (c), The display of the maximum value and the minimum value of d) is switched at a predetermined time interval. In (d), the maximum value is displayed in the first display area 32 and the minimum value is displayed in the second display area 34. When the mode button is pressed from the peak / bottom hold display of (b), the display mode returns to (a). As described above, the peak / bottom hold display and the display mode are toggled by pressing the mode button.

Switching between the display mode and the setting mode is performed by a mode switching unit. In this example, switching is performed by long-pressing a mode button that is a mode switching unit. Needless to say, a display mode / setting mode switching button may be provided separately.
(Setting mode)

In the setting mode, one of a plurality of detection modes prepared in advance is selected, and settings are made for each selected detection mode. In this example, five detection modes are prepared as described above, and any one of an independent detection mode, a height discrimination mode, a background fluctuation detection mode, a liquid level window mode, and a zone control mode can be selected. 28 to 32 show a setting mode setting method according to each detection mode. FIG. 28 shows the setting procedure of the independent detection mode, FIG. 29 shows the setting procedure of the height discrimination mode, and FIG. 30 shows the background fluctuation. The detection mode setting procedure, FIG. 31 shows the liquid level window mode setting procedure, and FIG. 32 shows the zone control mode setting procedure.
(Independent detection mode setting)

When the mode button is pressed for a long time from the state of FIG. 27, a transition is made to the setting mode as shown in FIG. FIG. 28 (1) is a screen for selecting a detection mode, “Fnc” indicating that the detection mode selection screen is displayed in the first display area 32, and each detection mode in the second display area 34. Here, when the up / down button is operated, the second display area 34 is toggled to “F-1”, “F-2”, “A-1”, “A-2”, “A-3”, “Independent detection mode”, “height discrimination mode”, “background fluctuation detection mode”, “liquid level window mode”, and “zone control mode” are shown respectively. Here, “F-1” corresponding to the “independent detection mode” is selected.
(Distance display mode selection)

When the mode button is pressed while the second display area 34 is in the “F-1” state, the independent detection mode is selected, and the screen shifts to the distance display mode selection screen shown in FIG. The distance display mode (dSt) is measured as a normal operation (nor) for displaying a detection distance from the irradiation surface (detection surface) of the sensor head unit 10 to the workpiece W, that is, the normal display mode described above, as shown in FIG. A reverse operation (rEv) for converting the measured distance, that is, an arbitrary reference position is set, and a conversion display mode for displaying the height of the workpiece W from the reference position is selected. When the reverse operation is set, an input screen for the reference set distance (dSt) is displayed as shown in FIG. Enter the reference position numerically from this screen. Here, the numerical value is specified by increasing / decreasing with the up / down buttons, but the numerical value can also be specified with a numeric keypad or dial. Thus, when reverse is set on the setting screen of the independent detection mode, it is possible to perform reverse display similar to the height determination mode described later.
(I / O terminal setting)

When the mode button is further pressed, a transition is made to an input / output terminal setting (I_O) screen shown in FIG. Here, the use of the input / output terminals provided together with the two output terminals (OUT1, OUT2) can be selected, and either analog output (out), external shift input (SFt), or bank input (bnk) is selected. .
(Analog output)

In the analog output, an analog signal having a value corresponding to the measured display value is output. An example of an analog signal waveform with respect to the display value will be described with reference to FIG. In the example of this figure, the electric current value (4-20 mA in the example of a figure) according to a measured value is output as an analog signal. When the detection distance to the workpiece W is less than the detection range lower limit or more than the detection range upper limit, the output is constant at the minimum value or the maximum value. When a head disconnection error is detected, a predetermined signal (for example, a minimum value) can be output from the analog output to perform an alarm operation. In the alarm operation, for example, when the conveyor C corresponding to the background cannot be detected by deviating from a predetermined position, an alarm is output as the sensor installation state is abnormal. In this example, the current value is output as an analog signal, but it goes without saying that it may be a voltage signal or a digital signal output.
(External shift input)

  In the external shift input, the display value is set to be shifted by a predetermined amount. External shift is effective for severe detection with little sensitivity difference. When the display value fluctuates due to an environmental change such as a temperature change, the display value can be corrected by an external shift input immediately before detection. For example, as shown in FIG. 35, the input / output terminal is connected to a switch, a PLC, or the like and short-circuited as shown in the figure to enable shift input. In this example, shift input is performed at the rising edge of the input signal.

When the external shift input is selected, a screen for specifying the shift target value distance (SFt) is displayed as shown in FIG. When the reverse operation is selected in the distance display mode described above, the external shift input cannot be selected. This is because the reference position is set also in the reverse operation, so that it is prevented from being confused with the external shift input which is the same operation. In this way, only necessary items are displayed as setting items, and the display of items that do not require setting is omitted, thereby eliminating user confusion and making the settings easy to understand.
(Bank input)

In the bank input, it is used as a trigger for switching the existing two-output page. That is, when the threshold values for two outputs are P1 and P2, respectively, when the input / output terminal receives a bank input, the threshold values for the two outputs can be changed to P1 ′ and P2 ′. There can be two thresholds.
(Output format setting)

When the mode button is pressed after the input / output terminal setting is completed, the screen shifts to the output format (out) setting screen shown in FIG. On the output format setting screen, the normal open operation or the normal close operation can be switched for each of the two outputs (OUT1, OUT2). In the example of FIG. 28 (4), the second digit of the second display area 34 is assigned to OUT1, the third digit is assigned to OUT2, and normal open is expressed as “o” and normal close is expressed as “C”, respectively. Yes. Here, when OUT1 is normally open and OUT2 is normally open, "no", when OUT1 is normally closed, OUT2 is normally open, "nCo", when OUT1 is normally open, and OUT2 is normally closed, "noC" When OUT1 is normally closed and OUT2 is normally closed, it is expressed by “nCC”.
(Response speed setting)

When the mode button is pressed after the output format setting is completed, a transition is made to the response speed setting screen (Spd) in FIG. On the response speed setting screen, the response time is specified as the response speed, and it does not respond to changes less than the specified number of seconds. Thereby, a minute change and chattering can be prevented. In the example of FIG. 28 (5), a predetermined numerical value is presented as an option in advance, and any numerical value is selected and set. However, the user can directly specify a desired numerical value.
(Hysteresis setting)

When the mode button is pressed after the response speed setting is completed, a transition is made to the hysteresis setting screen (Hys) in FIG. On the hysteresis setting screen, the hysteresis for the set threshold value is set as a numerical value (here, mm). Thereby, a delay and a range can be set according to the detection mode, and chattering and the like can be prevented. The hysteresis is automatically inputted with a numerical value during tuning (initial setting), but the user can change this value further.
(Power saving setting)

When the mode button is pressed after the hysteresis setting is completed, a transition is made to the power saving mode setting screen (Eco) in FIG. On this screen, the power saving mode (eco mode) can be switched ON / OFF. When the power saving mode is turned ON, the screen display of the displacement display section turns off and displays after a predetermined time (for example, 10 seconds). The power required (here, the power consumption of the LED of the 7-segment display) can be saved. If there is any input or button operation while the light is off, the screen display will turn on again and turn off after a few seconds.
(Display settings)

  When the mode button is pressed after the power saving setting is completed, the display changes to the display setting screen (dSp) in FIG. On this screen, various settings relating to the display of the displacement display section can be selected, and standard display (Std), filtering display (FLt), and digit number reduction display (diG) are switched by toggle. The standard display maintains the normal display form. The filtering display smoothes the display value. The digit number reduction display is a mode in which the number of digits of the display value is reduced by one lower digit, and can be changed from mm display to cm display.

In the setting mode, in order to end the setting mode and return to the display mode, similarly, the mode button is pressed and held. At this time, the value displayed in the setting mode is held as the setting value.
(Setting height discrimination mode)

  Next, the setting of the height discrimination mode will be described with reference to FIG. Note that description of the same items as in the independent detection mode described above will be omitted as appropriate. In the state shown in FIG. 27, the mode button is pressed and held to change to the setting mode, and the detection mode selection screen (Fnc) shown in FIG. 29 (1) is displayed. From this state, the up and down buttons are operated to display “F-2” corresponding to the “height discrimination mode” in the second display area 34, and the mode button is pressed to select. Then, it shifts to the setting of the height discrimination mode, and shifts to the distance display mode selection screen (dSt) as shown in FIG. Unlike FIG. 28 (2), in the height determination mode, the screen is always driven in the reverse operation, so the screen for selecting the normal operation is omitted, and the reference distance in the direct reverse operation is set as a numerical value.

Next, the screen shifts to the input / output terminal setting screen (i_o) in FIG. 29 (3), and the operation of the input / output terminal is selected from either analog output (out) or bank input (bnk). Here, the external shift input cannot be selected. Further, the screen shifts to the output format setting screen (out) of FIG. 29 (4), and the normal output or the normal close is set for each of the two outputs OUT1 and OUT2 as in FIG. 28 (4). Thereafter, the screen shifts to the response speed setting screen (SPd) in FIG. 29 (5), and the detection speed is selected from a predetermined selection value as in FIG. 28 (5). Further, in FIG. 29 (6), the screen shifts to a hysteresis setting screen (Hys), and a hysteresis value is designated. Furthermore, in FIG. 29 (7), the screen shifts to the power saving setting screen (Eco), and the eco mode ON / OFF is designated. Finally, the display setting screen (dSP) is displayed in FIG. 29 (8), and the standard display (Std), filtering display (FLt), and digit reduction display (diG) are switched by toggle.
(Background fluctuation detection mode setting)

Further, setting of the background fluctuation detection mode will be described with reference to FIG. From the state of FIG. 27, the mode button is pressed and held to change to the setting mode, and the detection mode selection screen (Fnc) shown in FIG. 30 (1) is displayed. From this state, the up and down buttons are operated to display “A-1” corresponding to the “background variation detection mode” in the second display area 34, and the mode button is pressed to select. Then, the process shifts to the setting of the background fluctuation detection mode, and shifts to the distance display mode selection screen (dSt) as shown in FIG. Here, as in FIG. 29 (2), the screen is always driven in the reverse operation, so the screen for selecting the normal operation is omitted, and the reference distance in the direct reverse operation is set as a numerical value. In the background fluctuation detection mode, since the operation of the input / output terminal is fixed to the analog output (out), the setting screen of the input / output terminal setting screen (i_o) is not displayed and the output format setting screen (3) in FIG. (out), and normally open or normally closed is set for each of the two outputs OUT1 and OUT2 as in FIG. 28 (4). Thereafter, the screen shifts to the response speed setting screen (SPd) in FIG. 30 (4), and the detection speed is selected from a predetermined selection value as in FIG. 28 (5). Further, the screen shifts to the hysteresis setting screen (Hys) in FIG. 30 (5), and the hysteresis value is designated. Further, in FIG. 30 (6), the screen shifts to the power saving setting screen (Eco), and the eco mode ON / OFF is designated. Finally, the display setting screen (dSP) is displayed in FIG. 30 (7), and the standard display (Std), filtering display (FLt), and digit reduction display (diG) are switched by toggle.
(Liquid level window mode)

Furthermore, the setting of the liquid level window mode will be described with reference to FIG. From the state of FIG. 27, the mode button is pressed and held to change to the setting mode, and the detection mode selection screen (Fnc) shown in FIG. 31 (1) is displayed. From this state, the up and down buttons are operated to display “A-2” corresponding to the “liquid level window mode” in the second display area 34, and the mode button is pressed to select. Then, the screen shifts to the setting of the liquid level window mode, and the screen shifts to the distance display mode selection screen (dSt) as shown in FIG. Here, as in FIGS. 29 and 30 (2), the screen is always driven in the reverse operation, so the screen for selecting the normal operation is omitted, and the reference distance in the direct reverse operation is set as a numerical value. In the liquid level window mode, since the operation of the input / output terminal is fixed to the analog output (out), the setting screen of the input / output terminal setting screen (i_o) is not displayed, and the output mode setting screen (3) in FIG. (out), and normally open or normally closed is set for each of the two outputs OUT1 and OUT2 as in FIG. 28 (4). Thereafter, the screen shifts to the response speed setting screen (SPd) in FIG. 31 (4), and the detection speed is selected from a predetermined selection value as in FIG. 28 (5). Further, the screen shifts to the hysteresis setting screen (Hys) in FIG. 31 (5), and the hysteresis value is designated. Further, the screen shifts to the power saving setting screen (Eco) in FIG. 31 (6), and the eco mode ON / OFF is designated. Finally, the display setting screen (dSP) is displayed in FIG. 31 (7), and the standard display (Std), filtering display (FLt), and digit reduction display (diG) are switched by toggle.
(Zone control mode)

  Further, the setting of the zone control mode will be described with reference to FIG. From the state shown in FIG. 27, the mode button is pressed and held to shift to the setting mode, and the detection mode selection screen (Fnc) shown in FIG. 32 (1) is displayed. From this state, the up and down buttons are operated to display “A-3” corresponding to “zone control mode” in the second display area 34, and the mode button is pressed to select. Then, the process proceeds to the setting of the zone control mode, and the process proceeds to the distance display mode selection screen (dSt) as shown in FIG. Here, as in FIGS. 29, 30 and 31 (2), since it is always driven in the reverse operation, the screen for selecting the normal operation is omitted, and the reference distance in the direct reverse operation is set as a numerical value.

Next, the screen shifts to the input / output terminal setting screen (i_o) in FIG. 32 (3), and the operation of the input / output terminal is selected from either analog output (out) or bank input (bnk). Here, the external shift input cannot be selected. Further, the screen shifts to the output format setting screen (out) in FIG. 32 (4), and the normal output or the normal close is set for each of the two outputs OUT1 and OUT2 as in FIG. 28 (4). Thereafter, the screen shifts to the response speed setting screen (SPd) in FIG. 32 (5), and the detection speed is selected from a predetermined selection value as in FIG. 28 (5). In the zone control mode, hysteresis setting is not performed, and the screen shifts to the power saving setting screen (Eco) in FIG. 32 (6) to specify ON / OFF of the eco mode. Finally, the display setting screen (dSP) is displayed in FIG. 32 (7), and the standard display (Std), filtering display (FLt), and digit reduction display (diG) are switched by toggle.
(Photoelectric sensor)

  In the above example, an ultrasonic sensor is used as a distance measuring unit. However, the present invention is not limited to this, and a sensor or a switch capable of measuring a distance or a displacement can be used as appropriate. For example, a CCD, a line CCD, a PSD or the like is used. The present invention can also be applied to other detectors such as a photoelectric sensor, a photoelectric switch, and a proximity switch. As an example, an example in which a photoelectric sensor is used as a distance measuring means will be described with reference to FIG. In this figure, members having the same member names as in FIG. 4 and the same reference numerals in the last two digits are members having the same functions, and detailed description thereof is omitted. In FIG. 36, the sensor head unit 910 includes a transmission unit 911 for irradiating the workpiece W with the ranging medium and a receiving unit 922 for receiving the ranging medium reflected by the workpiece W. The photoelectric sensor shown in FIG. 36 includes a transmission element that generates a distance measuring medium as the transmission unit 911 and a reception element that receives the distance measurement medium reflected by the workpiece W as the reception unit 912. Here, light is used as a distance measuring medium, a light emitting element such as an LED or an LD can be used as a transmitting element, and a light receiving element such as a PD or PSD can be used as a receiving element. These transmission element and reception element are connected to a transmission circuit 914 and a reception circuit 915 for driving each of them. Note that the configuration is not limited to the configuration in which the transmission unit and the light receiving unit are separately provided as in the example of FIG. 36, and the transmission unit and the reception unit may be integrated. With this configuration, the sensor head portion can be reduced in size and space can be saved. Needless to say, the sensor head unit and the amplifier unit can also have a structure in which these are integrated.

  The distance measuring sensor and its setting method of the present invention can be used for detecting whether or not a detection target exists at a detection position separated by a predetermined distance.

It is explanatory drawing explaining the example which displays the measured value which the sensor measured distance. It is explanatory drawing explaining the example which measures a workpiece | work with a sensor. It is a perspective view which shows the external appearance of an ultrasonic sensor. It is a block diagram which shows the sensor head part and amplifier part which comprise an ultrasonic sensor. It is explanatory drawing explaining the normal display mode which displays the measured distance on a display part as a display value. It is explanatory drawing explaining the conversion display mode which measures the distance from a reference position based on the measured distance. It is explanatory drawing explaining the example which displays the measured value in the example of arrangement | positioning including the state outside the detection range of a ranging sensor. It is explanatory drawing explaining the other example which displays the measured value in the example of arrangement | positioning including the state outside the detection range of a ranging sensor. It is explanatory drawing which shows the example which sets a threshold value in the case of normal display mode. It is explanatory drawing which shows the example which sets a threshold value in the case of conversion display mode. It is a perspective view explaining the example which performs two-point tuning. It is explanatory drawing explaining the example which performs maximum sensitivity tuning in the case of normal display mode. It is explanatory drawing explaining the example which performs maximum sensitivity tuning in the case of conversion display mode. It is a perspective view which shows the example which performs full auto tuning. It is a perspective view which shows the example which performs conveyor tuning. It is a timing chart which shows the output pattern of the output part in independent detection mode. It is explanatory drawing which shows an example which detects the presence or absence of the workpiece | work conveyed on a conveyor. It is explanatory drawing which shows an example which detects a workpiece | work in height discrimination mode. It is explanatory drawing which shows an example of the threshold value and output pattern of height discrimination mode. It is explanatory drawing which shows an example which detects a workpiece | work in background fluctuation | variation detection mode. It is explanatory drawing which shows an example of the threshold value and output pattern of background fluctuation | variation detection mode. It is explanatory drawing which shows an example which detects a workpiece | work in liquid level window mode. It is explanatory drawing which shows an example of the threshold value of a liquid level window mode, and an output pattern. It is explanatory drawing which shows an example which detects a workpiece | work in zone control mode. It is explanatory drawing which shows an example of the threshold value and output pattern of zone control mode. It is explanatory drawing which shows the other example which detects a workpiece | work in zone control mode. It is explanatory drawing which shows the state transition diagram in display mode, (a) is a state which displays a display value in the 1st display area of a displacement display part, and displays one threshold value in a 2nd display area, (b) is others (C) shows a state in which the threshold value is switched to the peak / bottom hold display. It is explanatory drawing which shows the setting procedure of independent detection mode. Setting procedure of height discrimination mode Setting procedure of background fluctuation detection mode Liquid level window mode setting procedure Setting procedure of zone control mode It is explanatory drawing explaining the difference between normal display mode and conversion display mode. It is a wave form diagram which shows an example of the analog signal waveform output from an input / output terminal. It is explanatory drawing which shows an example using an input / output terminal as a shift input. It is a block diagram which shows the other example of the sensor head part and amplifier part which comprise an ultrasonic sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Ultrasonic sensor 10,910 ... Sensor head part 13 ... Transmission / reception element; 14,914 ... Transmission circuit; 15,915 ... Reception circuit 16 ... Cable part 20,920 ... Amplifier part 22,922 ... Input part 24,924 ... Calculation unit; 25, 925 ... Output pattern changing unit 26, 926 ... Setting unit; 27, 927 ... Mode switching unit 28, 928 ... Output unit 30, 930 ... Display unit; 32 ... First display area; 34 ... Second display Area 36 ... Output display section; 38 ... Channel indicator; 39 ... Sub-indicator 911 ... Transmission section; 912 ... Reception section 42 ... Increase / decrease section; 44 ... Determination section W ... Workpiece;

Claims (13)

A sensor head unit capable of irradiating the object with a distance measuring medium and detecting the distance measuring medium reflected by the object;
A calculation unit capable of calculating a distance from an irradiation surface of the sensor head unit to an object based on a value detected by the sensor head unit;
A setting unit for setting in advance a threshold value, a reference value, and a positive / negative direction of display with respect to the reference value;
The measurement distance calculated by the calculation unit is converted into a display value according to the reference value and the positive / negative direction set by the setting unit, and a displacement display unit that can be displayed,
An output unit capable of comparing a display value displayed on the displacement display unit with a threshold set on the setting unit and outputting in a predetermined ON / OFF operation pattern;
A distance measuring sensor comprising: The distance measuring sensor according to claim 1,
The distance measuring sensor, wherein the display value in the displacement display unit is a value obtained by calculating a difference between a measurement distance and a reference value according to a positive / negative direction set in the setting unit. The distance measuring sensor according to claim 1 or 2,
The setting unit is further configured to be able to switch the timing at which the output unit outputs a predetermined ON / OFF when the display value exceeds or falls below a threshold value. Distance sensor. The distance measuring sensor according to any one of claims 1 to 3,
When the sensor head unit cannot detect the distance measuring medium and the distance measured exceeds the distance range that can be measured by the distance measuring sensor, the display value corresponding to the reference value set in advance is measured as the displacement display. A distance measuring sensor configured to be able to display on a screen. The distance measuring sensor according to any one of claims 1 to 4,
The distance measuring sensor, wherein the setting unit is configured to be able to set a reference value in addition to a distance measurable by the sensor head unit. The distance measuring sensor according to any one of claims 1 to 5,
The sensor head unit transmits a distance measuring medium, and
A receiving unit for detecting a ranging medium;
And the transmitter and the receiver are controlled by the calculator. The distance measuring sensor according to claim 6,
The distance measuring sensor, wherein the transmitter and the receiver are made of the same member. The distance measuring sensor according to any one of claims 1 to 7,
The calculation unit calculates the distance from the irradiation surface of the sensor head unit to the object based on the time required for detecting the ranging medium irradiated by the sensor head unit and the traveling speed of the ranging medium. A ranging sensor characterized by being operable. The distance measuring sensor according to any one of claims 1 to 8,
A distance measuring sensor, wherein the distance measuring medium is an ultrasonic wave. The distance measuring sensor according to any one of claims 1 to 9,
The distance measuring sensor, wherein the display value in the displacement display unit is a value obtained by calculating a difference between a measurement distance and a reference value according to a positive / negative direction set in the setting unit. A sensor head capable of irradiating the object with ultrasonic waves and detecting the ultrasonic waves reflected by the object;
Multiplying the time required to detect the ultrasonic wave irradiated by the sensor head unit and the ultrasonic traveling speed, the distance from the irradiation surface of the sensor head unit to the object can be calculated as a measured value. And a calculation unit
A position for separating a predetermined distance from the sensor head portion in the traveling direction of the ultrasonic wave is set as a reference position of the display value, and a positive / negative direction of display with respect to the reference position is set, and a threshold for the display value is set. A setting section;
In accordance with the reference value set in the setting unit and the positive / negative direction, the display value is calculated by adding / subtracting the measurement value calculated in the calculation unit, and the displacement display unit capable of displaying the display value;
An output unit capable of outputting a predetermined ON / OFF when a display value displayed on the displacement display unit reaches a threshold set by the setting unit;
A distance measuring sensor comprising: The sensor head unit irradiates the object with the distance measuring medium, detects the distance measuring medium reflected by the object, and the object from the irradiation surface of the sensor head unit based on the value detected by the arithmetic unit with the sensor head unit A distance measuring sensor setting method capable of calculating a distance to a predetermined ON / OFF signal from an output unit by comparing a measured distance with a preset threshold value,
A step of setting at least one of a predetermined reference position or a difference amount serving as a display reference from a setting unit provided in the distance measuring sensor;
Setting a positive / negative direction of display with respect to the reference position as required;
Setting a threshold;
A measurement distance to the object measured by the sensor head unit is converted into a display value according to a reference position and a positive / negative direction set by the setting unit, and the display value is a threshold value set by the setting unit A predetermined distance measurement sensor setting method that outputs a predetermined ON / OFF signal from the output unit when reaching the value. The distance measuring sensor setting method according to claim 12, wherein the distance measuring sensor includes a displacement display unit,
A distance measurement sensor setting method, wherein a value obtained by shifting a measurement distance from a reference position according to the positive and negative directions set by the setting unit is displayed on the displacement display unit as a display value.

Images