JPH0626321U - Detection switch device - Google Patents

Abstract

(57) [Summary] [Purpose] The determination level is automatically set, and the detection margin frequency is displayed so that it is possible to recognize whether or not the detection operation corresponding to the usage environment can be executed. [Structure] The microcomputer 1 executes a setting program in response to the operation of the mode changeover switch 12 and the setting switches 10 and 11, stores the level of a detection signal depending on the presence or absence of an object to be detected, and detects them. Set the judgment level according to the level. Further, the microcomputer 1 calculates the detection margin frequency from those detection levels and causes the stable operation indicator lamp 14 to perform a blinking operation with the number of times of lighting according to the value. This makes it possible to quickly recognize whether or not there is a detection margin frequency adapted to the usage environment.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a detection switch device that determines the presence or absence of an object to be detected by comparing the level of a detection signal output from a detection unit with a determination level and outputs an object detection signal.

[0002]

[Prior art]

 A photoelectric switch, which is an example of this type of detection switch device, is provided with a light projecting element for irradiating the detection area with light and a light receiving element for receiving reflected light from the detection area, and the light receiving element according to the light receiving amount of the light receiving element. The presence or absence of an object is detected by determining whether or not the level of the detection signal exceeds a preset determination level.

In this case, the determination level for detecting the presence / absence of an object can be generally changed according to the detection condition, and recently, it is output from the light receiving element according to the presence / absence of the object. It is considered that the calculation is automatically performed by performing a calculation in a predetermined relationship based on the levels of the two detection signals.

For example, a detection signal when an object to be detected exists and a detection signal by light incident from the outside when an object to be detected does not exist are input, and the detection signal between the levels of the respective detection signals is input. By setting the level as the determination level, it is possible to reliably detect the presence or absence of an object to be detected even when there is some ambient light or noise.

As described above, the determination level can be automatically set to a level according to the environment, and the user has to perform a troublesome work such as operating a sensitivity setting volume or the like to set detection conditions. It is not necessary to do this, and the object can be set simply by operating the detection setting switch and non-detection setting switch using the object to be detected.

[0006]

[Problems to be solved by the device]

 By the way, in such a conventional configuration, when the difference between the detection level in the presence of the detected object and the detection level in the non-existent state is small, for example, the level of the reflected light from the detected object and the background When the levels of the incident light from are close to each other, the determination level to be set depends on the slight level difference of the detection signals.

However, when the determination level is set in the state of such a minute level difference, the detection signal may be erroneously output due to the adverse effects of ambient light, noise, etc. even in the absence of the object to be detected, or However, due to the hysteresis characteristic of the comparator, there is a possibility that once the detection state is determined, the detection state remains unreset even if the detected object does not exist.

Therefore, for example, when the product flowing through the line is used as the detected object of the photoelectric switch, the detection output can be reliably performed only in the presence of the detected object according to the determination level set as described above. It is necessary to test whether it can be obtained. If the test result shows that the detection operation cannot be performed reliably, it is necessary to perform the setting work again, which is a troublesome work for the user, and there is a problem that the usability is deteriorated.

Further, at that time, even if the detection level is reset and the detection operation is performed, it is not known whether there is a sufficient margin for the ambient light or noise. It is a situation where it is not possible to determine whether or not it is reliable with respect to noise and noise, and there is still a risk of false detection depending on the usage environment.

The present invention has been made in view of the above circumstances, and an object thereof is to set a determination level of the presence or absence of an object with a simple operation, and to set the determination level when the determination level is set. Another object of the present invention is to provide a detection switch device capable of confirming at the same time how much margin can prevent erroneous detection due to ambient light or noise.

[0011]

[Means for Solving the Problems]

 The present invention is directed to a detection switch device that determines the presence or absence of an object to be detected by comparing the level of a detection signal output from a detection unit with a determination level and outputs an object detection signal. A first setting switch operated in the presence of the detected object, a second setting switch operated in the absence of the detected object, and a second setting switch operated when the first setting switch is operated. The level of the detection signal supplied from the detection unit is set as the first detection level, and the level of the detection signal supplied from the detection unit when the second setting switch is operated is stored as the second detection level. Judgment level setting means for setting the judgment level based on the first and second detection level values and a detection margin frequency according to the difference between the first and second detection level values That a calculating means, characterized in was constructed by providing the display means to further display the detected margin frequency by the calculating means to the number of lighting times.

[0012]

[Action]

 According to the detection switch device of the present invention, when the first setting switch is operated in the presence of the object to be detected and the second setting switch is operated in the absence of the object to be detected, the determination level setting means is , Stores the levels of the first and second detection signals obtained in each state, and sets the determination level based on those levels. Then, the calculation means calculates the detection margin frequency according to the stored difference between the first detection level and the second detection level, and the display means lights the detection margin frequency calculated by this calculation means. It will be displayed depending on the number of times. Therefore, the user can confirm the detection margin frequency by visually observing the number of times the display means is lit, and whether the set judgment level has a sufficient margin based on the magnitude of the detection margin frequency. That is, it is possible to confirm whether there is a sufficient difference in the detection level depending on the presence or absence of the detected object. This makes it possible, for example, to determine the required detection margin frequency according to the conditions of the operating environment, that is, the incident conditions such as ambient light and noise at the installation location. It can be set so that it can perform various detection operations.

[0013]

【Example】

 An embodiment in which the present invention is applied to a reflection type photoelectric switch will be described below with reference to the drawings. In FIG. 1 showing the overall electrical configuration, a microcomputer 1 is a so-called one-chip microcomputer in which a CPU, a ROM, a RAM, an A / D conversion circuit and the like are built in, and a decision level setting means and a computing means. The object detection program (not shown) and a setting program to be described later are stored in advance.

A power supply input terminal VD of the microcomputer 1 is connected to a DC power supply line 2, and a predetermined voltage is applied from a DC power supply (not shown) via the power supply terminal V and the constant voltage circuit 3. The ground terminal of the microcomputer 1 is connected to the ground terminal E.

The anode of the light projecting element 4 such as a light emitting diode is connected to the DC power supply line 2 via the drive circuit 5, and the cathode is connected to the ground terminal E. The drive circuit 5 is connected to the output terminal a of the microcomputer 1 and is adapted to receive a light emitting pulse signal. The light emitting element 4 is caused to perform a light emitting operation in accordance with the light emitting pulse signal. It has become.

The cathode of the light receiving element 6 such as a photodiode is connected to the DC power supply line 2, and the anode is connected to the ground terminal E via the bias circuit 7 and the input terminal of the light receiving amplifier 8. The output terminal of the light receiving amplifier 8 is connected to the input terminal b of the microcomputer 1 via the main amplifier 9. The microcomputer 1 converts the analog detection signal, which is amplified by the main amplifier 9 and then applied to the input terminal b, into a digital signal by the A / D conversion function.

The detection-time setting switch 10 as the first setting switch and the non-detection-time setting switch 11 as the second setting switch are connected to the input terminals c and d of the microcomputer 1, respectively, and the mode changeover switch 12 is used. Is connected to the input terminal e of the microcomputer 1. The anodes of the operation indicator lamp 13 and the stable operation indicator lamp 14 such as light emitting diodes are connected to the DC power supply line 2, and the cathodes thereof are connected to the output terminals f and g of the microcomputer 1, respectively. As will be described later, the stable operation indicator lamp 14 also has a function as a display means, and performs a blinking operation to display the detection margin frequency by the number of times of lighting.

The data input / output terminal of the EEPROM (rewritable non-volatile memory) 15 is connected to the input / output terminal h of the microcomputer 1. The microcomputer 1 is adapted to read or write necessary data from the EEPROM 15 at any time as described later. The external output terminal P for object detection is connected to the output terminal i of the microcomputer 1 via the output circuit 16.

Next, the operation of this embodiment will be described with reference to FIG. Here, (1) the detection operation will be briefly described, and then (2) the determination level setting operation will be described with reference to the flowchart of the setting program shown in FIG.

(1) Detection Operation When the mode selector switch 12 is set to the detection mode with the power turned on, the microcomputer 1 performs the following operation according to a detection program (not shown). Perform detection operation. That is, the microcomputer 1 outputs a light emitting pulse signal to the drive circuit 5 to cause the light emitting element 4 to pulse-light at a predetermined frequency. When the object to be detected is present, the pulsed light from the light projecting element 4 is reflected by the object to be detected and enters the light receiving element 6.

As a result, when a light receiving signal corresponding to the amount of light received is output from the light receiving element 6, the light receiving signal amplified via the light receiving amplifier 8 and the main amplifier 9 is input to the input terminal b of the microcomputer 1. Will be given. The microcomputer 1 converts an analog light receiving signal given to the input terminal b into a digital detection signal by an A / D conversion function and inputs it, and the level of the detection signal is set as described later. Compare with judgment level K.

When the microcomputer 1 determines that the level of the detection signal is higher than the determination level K, it counts as the presence of light, and when the count reaches a predetermined number, it outputs from the output terminal i to the output circuit 16 The object detection signal is output to the external output terminal P via the output terminal and the display signal is output to the output terminal f to turn on the operation indicator lamp 13. Thus, for example, if a load drive circuit or the like is connected to the external output terminal P, the load is driven by the object detection signal, and the user is notified by turning on the operation indicator lamp 13.

Further, when the above-described detection operation is performed, the microcomputer 1 compares the input detection signal with a preset stable detection level that is higher than the above-described determination level K, and detects the detection signal. When it is determined that the level is higher than the stable detection level, it is determined that the stable light input state is reached, and the display signal is output from the output terminal g to turn on the stable operation indicator lamp 14. As a result, it is displayed that this detection state is stable.

(2) Judgment Level Setting Operation When the user switches the mode selector switch 12 to “SET” in order to set the judgment level K in the detection operation as described above, the microcomputer 1 executes the setting program according to the flowchart shown in FIG.

That is, the microcomputer 1 determines in step S1 and S2 which of the detection setting switch 10 and the non-detection setting switch 11 is turned on, and when neither of the switches 10 and 11 is turned on. Both are determined to be "NO" and the process proceeds to step S3. If the mode changeover switch 12 is in the "SET" state, it is determined to be "YES" and the process returns to step S1.

After that, the microcomputer 1 repeats Steps S1, S2 and S3, and the detection time setting switch 10 is turned on by the user to set the detection level in the state where the object to be detected exists. In some cases, it is determined "YES" in step S1 and the process proceeds to step S4.

In step S 4, the microcomputer 1 causes the light projecting element 4 to perform the light projecting operation in the same manner as described above, and the light receiving element 6 causes the light receiving element 8 to pass through the light receiving amplifier 8 and the main amplifier 9 by the reflected light from the object to be detected. The digital detection signal obtained by A / D converting the received light input signal is read as the detection level V1 and is further written and stored in the EEPROM 15.

Next, the microcomputer 1 sets the determination level K based on the currently detected detection level V1 and the previously set non-detection level V2. In this case, the non-detection level V2 is provisionally set, and as will be described later, the non-detection level V2 corresponding to the operating environment installed when the non-detection time setting switch 11 is turned on is set. It has become so. Now, the microcomputer 1 calculates the average value of the detected level V1 and the non-detected level V2 and stores it as the determined level K (= (V1 + V2) / 2).

Subsequently, when the microcomputer 1 proceeds to step S6, it calculates the detection margin frequency S. That is, the microcomputer 1 first calculates the difference ΔS (= V1−V2) between the detected level V 1 and the non-detected level V2, and sets the value of 20% of the determination level K to the margin index. It is calculated as N (= 0.2 × K). Next, the microcomputer 1 calculates the ratio of the detection level difference ΔS to the margin index N as the detection margin number S. That is, the detection margin frequency S can be obtained as the detection margin frequency S = ΔS / N.

As a result, the processing by turning on the detection time setting switch 10 is completed, and the microcomputer 1 returns to step S1 through step S3, and repeats steps S1, S2 and S3. When the non-detection switch 11 is turned on, the microcomputer 1 determines "YES" in step S2 and proceeds to step S7.

In step S7, the microcomputer 1 inputs the detection signal in the state in which the detected object does not exist in the same manner as described above, reads the level as the non-detection level V2, writes it in the EEPROM 15, and uses it. The non-detection level V2 corresponding to the environment is stored.

In this way, when the detection and non-detection levels V1 and V2 are obtained, the microcomputer 1 again calculates the determination level K in steps S5 and S6, and also calculates the detection margin frequency S. Will be remembered. Thereafter, the micro computer 1 repeats steps S1 and S2 while judging in step S3 that the mode changeover switch 12 is released from the "SET" state.

When the setting of the detection-time level V1 and the non-detection level V2 is completed and the user releases the mode selector switch 12 from the “SET” state, the microcomputer 1 returns “NO” in step S3. Then, the process proceeds to step S8. In step S8, the microcomputer 1 outputs a display signal of the number of times of lighting corresponding to the stored detection margin frequency S from the output terminal g, causes the stable operation indicator lamp 14 to blink, and returns to the detection program. In this case, the number of times the stable operation indicator lamp 14 is turned on is set to, for example, 0 times up to 5 times.

As a result, the user can recognize whether or not the detection operation based on the detection-time level V1 and the non-detection-time level V2 that has just been set has a margin. That is, for example, when the number of times the stable operation indicator lamp 14 is turned on is large, the difference between the detection-time level V1 and the non-detection-time level V2 is large, and the margin for performing the detection operation is also large.

In this case, the value of the detection margin frequency S is set to the margin index N in which the difference ΔS between the detection time level V1 and the non-detection time level V2 corresponds to 20% of the determination level K, as described above. Since it is calculated as a value that indicates how many times it is, if the detection margin frequency S is less than "1", a reliable detection operation cannot be guaranteed even when there is no ambient light or noise in the operating environment. Yes, if the value is 1 or more, the higher the value, the more reliably the detection becomes possible, and the accurate detection operation can be performed even when there is much ambient light or noise in the usage environment. It is shown that.

Therefore, as a guideline for the detection margin frequency S, when the location where the photoelectric switch is disposed is a usage environment where there is no ambient light or noise, the value of the detection margin frequency S is “1”. In a usage environment where there is a lot of ambient light or noise, if the value of detection margin frequency S is "3", a stable operation display that blinks after performing the judgment level setting operation is displayed. By observing the number of times the lamp 14 is turned on, it becomes possible to recognize whether or not the detection operation can be accurately performed, depending on the usage environment of the photoelectric switch at that time.

According to the present embodiment as described above, in the determination level setting operation, the determination level K is set by the microcomputer 1, and the detection margin frequency S is calculated to turn on the stable operation indicator lamp 14. Since the display is made according to the number of times, the user can easily set the determination level K by operating the detection setting switch 10 and the non-detection setting switch 11, and the determination level K can be set. In the setting process, it is possible to recognize the detection margin frequency S that is not erroneously detected by ambient light, noise, etc. by the number of times of lighting, and whether there is the detection margin frequency S adapted to the usage environment. Can be quickly determined.

Further, according to the present embodiment, since the stable operation indicator lamp 14 displays the number of times of lighting corresponding to the detection margin frequency S, it is possible to configure at low cost without separately providing a display means. it can.

Although the detection margin frequency S is displayed by using the stable operation indicator lamp 14 in the above embodiment, the present invention is not limited to this, and the operation indicator lamp 13 may be used, for example. Alternatively, a dedicated indicator light may be separately provided.

Further, in the above embodiment, the case where the determination level is set to the determination level K calculated as the average value of the detection-time level V1 and the non-detection-time level V2 has been described, but the invention is not limited to this. For example, a certain comparison reference level may be set in advance, and the amplification level of the light receiving amplifier may be changed to set the actual determination level, or the amount of light emitted by the light emitting element may be changed. By doing so, it may be set as a substantial determination level.

Further, in the above embodiment, the first and second setting switches are provided with the detection time setting switch 10 and the non-detection time setting switch 11, respectively, but the present invention is not limited to this. Instead, one setting switch may have the functions of the first and second setting switches. That is, for example, the setting program may function as a detection-time setting switch when the setting switch is first operated, and may function as a non-detection-time setting switch when the setting switch is operated next.

In the above embodiment, the mode changeover switch 12 is provided and the judgment level setting operation is executed by operating the mode changeover switch 12. However, the present invention is not limited to this, and the mode changeover switch is used, for example. Alternatively, the determination level setting operation may be executed when the detection setting switch 10 or the non-detection setting switch 11 is operated.

Further, in the above embodiment, the case where the present invention is applied to the photoelectric switch has been described, but the present invention is not limited to this and may be applied to other detection switches.

[0044]

[Effect of device]

 As described above, according to the detection switch device of the present invention, the determination level is automatically set by the operation of the first and second setting switches, and the calculation means and the display means enable the first and second determination switches to be set. Since the detection margin frequency according to the difference between the two detection levels is calculated and the detection margin frequency is displayed on the display means by the number of times of lighting, the judgment level can be set by a simple operation and the set judgment can be performed. Since it is possible to quickly recognize how much the detection margin frequency of the level is, even if there is an adverse effect due to ambient light or noise, for example, by recognizing whether or not the detection margin frequency required for the usage environment is present. It has an excellent effect of being able to judge whether or not the accurate detection operation can be performed.

[Brief description of drawings]

FIG. 1 is a schematic electrical configuration diagram showing an embodiment of the present invention.

[Fig. 2] Flow chart of setting program

[Explanation of symbols]

1 is a microcomputer (judgment level setting means, computing means), 2 is a DC power supply line, 4 is a light projecting element, 6 is a light receiving element, 8 is a light receiving amplifier, 9 is a main amplifier, 10 is a detection time setting switch (first Setting switch), 11 is a non-detection setting switch (second setting switch), 12 is a mode change switch, 13 is an operation indicator lamp, 14 is a stable operation indicator lamp (display means), and 15 is an EEPROM.

Claims (1)

[Scope of utility model registration request] 1. A detection switch device for determining the presence or absence of an object to be detected by comparing the level of a detection signal output from a detection section with a determination level, and outputting an object detection signal, wherein the object to be detected is present. A first setting switch that is operated in the state of being turned on, a second setting switch that is operated in a state in which the object to be detected does not exist, and is given from the detection unit when the first setting switch is operated. The level of the detection signal is set to a first detection level, and the level of the detection signal given from the detection unit when the second setting switch is operated is stored as a second detection level and the first and second detection levels are stored. Determination level setting means for setting the determination level based on the detection level value; and calculation means for calculating the detection margin frequency according to the difference between the first and second detection level values. Detecting switch device being characterized in that comprising a display means for displaying the number of lighting times of the detection margin frequency by the arithmetic means.