JPH07113636A - Analog-output distance measurement type photoelectric sensor - Google Patents

Abstract

PURPOSE:To provide an analog-output distance measurement type photoelectric sensor capable of displaying the abnormality of an operating output, excess incident light and the shortage of the amount of light by one pilot lamp and capable of intuitively recognizing an abnormal state. CONSTITUTION:A signal processing circuit 31 outputs one abnormal-state display signal when there is either output from comparison circuits 29, 30 detecting excess incident light and the shortage of the amount of light respectively. A display processing circuit 33 continuously lights an operation pilot lamp L1 when an output-state display signal is input from an output circuit 28, and the operation pilot lamp L1 is flickered while being synchronized with a pulse signal for a specified period acquired by frequency-dividing the pulse signal of an oscillation circuit 11 by a frequency dividing circuit 32 when a condition- state display signal is input from the signal processing circuit 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the distance to an object by irradiating the object with light and receiving the reflected light to measure the distance to the object. The present invention relates to an analog output distance measuring photoelectric sensor that outputs an ON / OFF signal according to the above.

[0002]

2. Description of the Related Art An analog output distance measuring photoelectric sensor of this type which has been provided conventionally has a structure shown in FIGS. That is, the light projecting element 1 forms the light beam by passing the output light through the light projecting lens 4, irradiates the detection object 3 with this light beam, and projects the surface of the detection object 3 into a dot-shaped light pattern. Form a light spot. The reflected light of the light projection spot is converged through the light receiving lens 5 to form a light reception spot as an image of the light projection spot on the light receiving surface of the position detection element 2 made of PSD. Therefore, the distance to the detection object 3 can be measured by the triangulation method based on the output of the position detection element 2.

The position detecting element 2 is imaged on the light receiving surface.
The ratio of signal values is determined according to the position of the light receiving spot.
Pair position signal I₁, I₂Is output on the light receiving surface.
Changes in the above ratio when the light spot moves by a unit distance.
Between the light emitting element 1 and the reference point of the position detecting element 2
Distance and when the light receiving spot is formed at the reference point
If the distance from the light projecting element 1 to the sensing object 3 is known,
If both position signals I₁, I ₂Based on the ratio of the signal values of
It is possible to obtain the distance from the light projecting element 1 to the sensing object 3.
Wear.

That is, as shown in FIG.
Is driven so that a pulse signal having a constant cycle output from the oscillation circuit 11 is passed through the light projecting circuit 12 to intermittently emit light at a constant cycle. On the other hand, both position signals I ₁ and I ₂ output from the position detecting element 2 are input to the light receiving circuits 21a and 21b, respectively. Since the position signals I ₁ and I ₂ are current signals, the light receiving circuits 21a and 21b have a current-
It performs voltage conversion and noise removal. The outputs of the light receiving circuits 21a and 21b are the two-stage amplifier circuits 2 respectively.
The voltage is amplified by 2a, 22b, 23a and 23b, and then input to the arithmetic circuit 24. The arithmetic circuit 24 outputs a signal according to the distance to the detection object 3 by dividing the signal values of the output signals of the amplifier circuits 23a and 23b. This signal is input to a sample and hold circuit 25 that captures and holds the input signal in synchronization with the pulse signal output from the oscillation circuit 11. Also,
The signal held in the sample and hold circuit 25 is amplified by the amplifier circuit 26 and output to the outside as an analog output that increases or decreases according to the distance to the sensing object 3. That is, the arithmetic processing unit is configured so that the light receiving circuits 21a, 2
1b, amplifier circuits 22a, 22b, 23a, 23b, arithmetic circuit 24, sample and hold circuit 25, amplifier circuit 26
It is composed of

Further, in the comparison circuit 27, a preset set distance is compared with the measured distance. For example, an ON signal is output when the measured distance exceeds the set distance, and an OFF signal is output in the following cases. , And at the same time, the operation indicator lamp LED ₁ composed of a light emitting diode is turned on at the time of ON output to display the output state.

Further, if the surface of the sensing object 3 has a high reflectance,
Therefore, the amount of light incident on the position detection element 2 is abnormally large.
Saturates amplifier circuits 22a, 22b and 23a, 23b
Like inputting a high level position signal
If the saturation level cannot be measured accurately,
And set the level immediately before that as the upper limit level
Output from the amplifier circuits 22a and 22b.
Position signal I₁, I ₂Voltage corresponding to the signal level of
The signal is compared with any of the amplifier circuits 22a and 22b.
The voltage signal level output from the
A first comparison circuit 29 that generates an output when
When there is an output from the comparator circuit 29 of FIG.
LED for over-incoming light which consists of light emitting diode₂To
It is designed to be turned on.

On the contrary, since the surface of the sensing object 3 is a surface having a low reflectance, the amount of light incident on the position detecting element 2 is abnormally small, and the amount of light incident on the position detecting element 2 is abnormally small, so that signal processing is performed. A lower limit level is set corresponding to the case where the minimum level required for performing is not reached, and the lower limit level is set to correspond to the signal level of the position signal I ₁ output from one designated amplification circuit, for example, 22a. A second comparison circuit 30 is provided which compares the voltage signal with the voltage signal and generates an output when the level of the voltage signal output from the amplification circuit 22a becomes equal to or lower than the lower limit level. Through the processing circuit 31, a light quantity shortage indicator lamp LED ₃ composed of a light emitting diode is turned on.

As described above, the conventional analog output distance-measuring photoelectric sensor indicates the operation output, excessive light, and insufficient light quantity by the indicator lamp LE.
It is designed to be individually displayed by D _{1 to} LED ₃ .

[0009]

However, in the above-mentioned conventional configuration, the number of indicator lamps is large, which is not suitable for downsizing and cost reduction of the product and intuitively recognizes an abnormal state from the outside. There was a problem that it took time. The present invention has been made in view of the above problems,
An object of the inventions of claims 1 and 2 is to provide an analog output range-finding type capable of displaying an operation output, an abnormality of excessive light input and an insufficient amount of light on one display lamp, and intuitively recognizing an abnormal state. In providing a photoelectric sensor.

In addition to the above object, the invention of claim 3 is
An object is to provide an analog output ranging photoelectric sensor capable of displaying that the light amount is in a stable state.

[0011]

According to a first aspect of the invention, in order to achieve the above object, a light-projecting element for irradiating a surface of a detection object with a light-projecting spot, and an object of light emitted from the light-projecting element. A pair of position signals that receive the reflected light on the surface and determine the ratio of the signal values corresponding to the position of the light receiving spot formed as an image of the light emitting spot and the total of the signal values is a monotonically increasing function of the received light amount Output position detection element, analog output corresponding to the distance to the object based on the signal values of both position signals, an arithmetic processing unit that outputs an ON / OFF signal according to the set distance, and an output state of the arithmetic processing unit In a distance-measuring photoelectric sensor equipped with an operation indicator lamp that lights up, the upper limit level set corresponding to the saturation level of the amplification means for amplifying a pair of position signals respectively and the signal level of at least one position signal And a first comparing means for generating an output when the signal level exceeds the upper limit level, and one position designated as the lower limit level corresponding to the minimum necessary level for performing signal processing. Second comparing means for comparing the signal level of the signal and generating an output when the signal level becomes equal to or lower than the lower limit level, and a display for blinking the operation indicator lamp when an output is generated by one of the comparing means. And a control means.

According to the second aspect of the present invention, a light projecting element for irradiating the surface of the detection object with a light projecting spot, and light reflected by the object surface of the light emitted from the light projecting element are received as an image of the light projecting spot. The ratio of the signal values is determined according to the position of the formed light receiving spot, and the position detection element that outputs a pair of position signals whose total signal value is a monotonically increasing function of the received light amount and the signal value of both position signals A distance measuring photoelectric sensor equipped with an analog output corresponding to the distance to an object, an arithmetic processing unit that outputs an ON / OFF signal according to a set distance, and an operation indicator that lights and displays the output state of the arithmetic processing unit. In the sensor, the operation indicator light whose emission color can be switched is compared with the upper limit level set corresponding to the saturation level of the amplification means for amplifying the pair of position signals, and at least the signal level of one position signal. First comparing means for producing an output when the signal level exceeds an upper limit level, and a signal level of one position signal designated as a lower limit level set in correspondence with the minimum necessary level for performing signal processing. And a second comparing means for generating an output when the signal level becomes equal to or lower than the lower limit level, and a light emission color of the operation indicator lamp when the output is generated by one of the comparing means. Display control means for switching to a color different from that when the output state is displayed is provided.

According to the invention of claim 3, in the structure of claim 1 or claim 2, the lower limit level is multiplied by a predetermined margin value to set a margin level larger than the lower limit level and smaller than the upper limit level. There is a third comparing means for comparing and detecting the signal level of one of the designated position signals and generating an output when the signal level exceeds the margin level, and an output of the third comparing means. And the first
The comparison means is provided with a margin display means for displaying that it is in a stable state when no output is generated.

[0014]

According to the first aspect of the present invention, the signal is obtained by comparing the upper limit level set corresponding to the saturation level of the amplifying means for amplifying the pair of position signals with the signal level of at least one position signal. The first comparing means for generating an output when the level exceeds the upper limit level, and the lower limit level set corresponding to the minimum necessary level for performing signal processing and the signal level of one designated position signal Comparing the signal level to a lower limit level or below, a second comparing means for producing an output, and a display control means for blinking the operation indicator lamp when an output is produced by one of the comparing means are provided. Therefore, the operation indicator that displays the output status of the arithmetic and control unit can be used to display the abnormal state of over-lighting and insufficient light intensity, and since it blinks, the user can intuitively recognize the abnormal state. That.

According to the second aspect of the present invention, the operation indicator lamp whose emission color can be switched and the upper limit level set corresponding to the saturation level of the amplifying means for amplifying the pair of position signals respectively, and at least one of them. And a lower limit level set in correspondence with the minimum level required for signal processing. The second display means for comparing the signal level of one designated position signal and generating an output when the signal level becomes equal to or lower than the lower limit level, and the above-mentioned operation display when an output is produced by either one of the comparison means. Since the display control means for switching the light emission color of the lamp to a color different from that at the time of displaying the output state of the arithmetic processing unit is provided, the operation indicator lamp for displaying the output state of the arithmetic control unit is not over-illuminated and the light amount is insufficient. Difference Also it is used for state display, and since the display time of the different color output state of the arithmetic processing unit luminescent color can be recognized to the user intuitively abnormal state.

According to the third aspect of the present invention, the lower limit level is multiplied by a predetermined margin value to set a margin level larger than the lower limit level and smaller than the upper limit level, and one of the position signals designated as the margin level is set. There is a third comparing means for comparing and detecting the signal level and generating an output when the signal level exceeds the margin level, and there is an output of the third comparing means and the first comparing means outputs. Since the margin display means for displaying the stable state is provided when is not generated, it is possible to inform the user that the light amount is stable.

[0017]

【Example】

(Embodiment 1) In the conventional configuration shown in FIG. 4, the indication of excessive light, insufficient light quantity, and output state is indicated by a separate indicator lamp, but in this embodiment, the operation indicator LED ₁ Is used to display an abnormal state of excessive incident light and insufficient light amount, and this embodiment is different from the conventional example in this respect. Since the basic circuit configuration of this embodiment is similar to the conventional configuration shown in FIGS. 3 and 4, in FIG. 1 showing the circuit configuration of this embodiment, the same numbers and symbols are given to the same configurations as the conventional example. The description will be omitted, and the points different from the conventional example will be described in detail below.

First, in this embodiment, the first and second comparison circuits 2
A signal processing circuit 31 that outputs one abnormal state display signal when any of the outputs 9 and 30 is provided is provided, and when the output state display signal is input from the output circuit 28, the operation indicator lamp L ₁ is continuously turned on. When the circumstance state display signal is input from the signal processing circuit 31, the operation indicator lamp L ₁ blinks in synchronization with a pulse signal of a predetermined cycle obtained by dividing the pulse signal of the oscillation circuit 11 by the frequency dividing circuit 32. A display processing circuit 33 is provided. That is, the signal processing circuit 31, the display processing circuit 33, and the frequency dividing circuit 32 constitute display control means for controlling the operating state of the operation indicator lamp L ₁ .

Therefore, the operation indicator LED₁Is the processing unit
Table of output status indicators and abnormal conditions such as excessive light intensity and insufficient light intensity
It also serves as an indicator light, and if the number of indicator lights can be reduced.
LED indicator for operation₁Is displayed intuitively to the user
The displayed contents can be recognized. Also this implementation
In the example, the margin table for displaying the stable light amount
Indicator LED ₀Is equipped with.

That is, the lower limit level is multiplied by a predetermined margin value to set a margin level larger than the lower limit level and smaller than the upper limit level, and this margin level and one of the designated position signals I ₁ are dealt with. Amplifier circuit 22a
Of the output level of the amplifier circuit 22a
Signal output circuit 3 when the output level exceeds
A third comparison circuit 34 for outputting to 1 is provided. The signal processing circuit 31 lights the margin indicating lamp LED ₀ composed of a light emitting diode when the output of the comparison circuit 34 is present and the output of the comparison circuit 29 for comparison with the upper limit level is not present.

In other words, it is possible to indicate to the user that the present light amount is stable by displaying the margin indicator LED ₀ . If the light emission color of the allowance indicator light LED ₀ is different from the light emission color of the operation indicator light LED ₁ , the distinguishability can be improved. (Embodiment 2) In the above-mentioned Embodiment 1, the output status display is carried out by continuously lighting the operation indicator LED _1, and the abnormal status display is carried out by flashing it. As shown in 2, a two-color light emitting display element in which two light emitting diodes La and Lb having different light emitting colors are incorporated in one package is used as the operation indicator LED ₁ , and the output state and the abnormal state are displayed by switching the light emitting color. It is designed to distinguish between and. . That is, the display processing circuit 33 turns on the light emitting diode La to display, for example, red color when the output state display signal from the output circuit 28 is input, and turns on the light emitting diode Lb when the abnormal state display signal is input from the signal processing circuit 31. Then, for example, green display is performed.

Therefore, the user can easily recognize whether it is the abnormal state display or the output state display only by looking at the light emission color.
Of course, if the emission colors of these margin display lamps LED ₀ provided in parallel with these display colors are made different, the distinguishability of the margin display can be improved. Since the configuration other than the display relation is the same as that of the first embodiment, the same numbers and symbols are given in FIG. 2 and the description thereof is omitted.

[0023]

According to the first aspect of the invention, the upper limit level set corresponding to the saturation level of the amplifying means for amplifying the pair of position signals is compared with the signal level of at least one position signal. And a signal level of one position signal designated as a lower limit level set corresponding to the minimum level required for signal processing, when the signal level exceeds the upper limit level. And a second control means for generating an output when the signal level becomes equal to or lower than the lower limit level, and a display control means for blinking the operation indicator lamp when an output is generated by one of the comparison means. Therefore, the operation indicator that displays the output status of the arithmetic and control unit can be used to display the abnormal status of over-lighting and insufficient light intensity, and since it blinks, the user can intuitively recognize the abnormal status. Are those capable, also since it only operation indicator, miniaturization Hakare mounting space indicator is smaller, also has the effect that the cost can be reduced.

According to the second aspect of the present invention, the operation indicator light whose emission color can be switched and the upper limit level set corresponding to the saturation level of the amplifying means for amplifying the pair of position signals respectively, and at least one of them. The first comparing means for comparing the signal level of the position signal of No. 1 with the signal level of the position signal to generate an output when the signal level exceeds the upper limit level, and the lower limit level set corresponding to the minimum level required for signal processing. The second level comparison means for generating an output when the signal level of the designated one position signal is compared to the lower limit level by comparing the signal levels of the designated one position signals, and the output is generated by either one of the comparison means. The operation indicator lamp for displaying the output state of the arithmetic control unit is provided with the display control means for switching the emission color of the operation indicator lamp to a color different from that when the output state of the arithmetic processing unit is displayed. It can also be used to display an abnormal state of excessive light, insufficient light quantity, and since the color of the emitted light is different from that when the output state of the arithmetic processing unit is displayed, the user can intuitively recognize the abnormal state, Further, since only the operation indicator lamp of two-color light emission is required, there is an effect that the mounting space of the indicator lamp can be reduced, the size can be reduced, and the cost can be reduced.

According to the third aspect of the invention, the lower limit level is multiplied by a predetermined margin value to set a margin level larger than the lower limit level and smaller than the upper limit level, and one of the position signals designated as the margin level is set. There is a third comparing means for comparing and detecting the signal level and generating an output when the signal level exceeds the margin level, and there is an output of the third comparing means and the first comparing means outputs. Since the margin display means for displaying that the light source is in a stable state when not being generated is provided, it is possible to inform the user that the light amount is stable.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a first embodiment.

FIG. 2 is a block circuit diagram of a second embodiment.

FIG. 3 is a schematic configuration diagram showing an optical system of an analog output distance measuring photoelectric sensor.

FIG. 4 is a block circuit diagram showing a conventional example.

[Explanation of symbols]

2 Position detecting element 11 Oscillation circuit 12 Light emitting circuit 21a Light receiving circuit 21b Light receiving circuit 22a Amplifying circuit 22b Amplifying circuit 23a Amplifying circuit 23b Amplifying circuit 24 Operation circuit 25 Sample and hold circuit 26 Amplifying circuit 27 Comparison circuit 28 Output circuit 29 Comparison circuit 30 Comparison circuit 31 Signal processing circuit 32 Frequency division circuit 33 Display processing circuit LED ₁ operation indicator LED ₀ margin indicator lamp

Claims (3)

[Claims] 1. A light projecting element for irradiating a light projecting spot on the surface of a detection object, and a light receiving spot formed as an image of the light projecting spot by receiving reflected light on the object surface of light emitted from the light projecting element. The position detection element that outputs a pair of position signals whose total signal value is a monotonically increasing function of the received light amount and the ratio of the signal values is determined according to the position of A distance measuring photoelectric sensor including an analog output corresponding to a distance, an arithmetic processing unit that outputs an ON / OFF signal according to a set distance, and an operation display lamp that lights up and displays the output state of the arithmetic processing unit. An output is generated when the upper limit level set corresponding to the saturation level of the amplifying means for amplifying each position signal is compared with the signal level of at least one position signal and the signal level exceeds the upper limit level. The comparison means 1 and the lower limit level set in correspondence with the minimum necessary level for performing signal processing are compared with the signal level of one designated position signal, and output when the signal level becomes equal to or lower than the lower limit level. Analog output distance measuring photoelectric sensor, comprising: a second comparing means for generating a signal and a display control means for causing the operation indicator lamp to blink when an output is generated from one of the comparing means. . 2. A light projecting element for irradiating a light projecting spot on the surface of a detection object, and a light receiving spot formed as an image of the light projecting spot by receiving reflected light on the object surface of light emitted from the light projecting element. The position detection element that outputs a pair of position signals whose total signal value is a monotonically increasing function of the received light amount and the ratio of the signal values is determined according to the position of A distance measuring photoelectric sensor equipped with an analog output corresponding to the distance, an arithmetic processing unit that outputs an ON / OFF signal according to the set distance, and an operation indicator that lights and displays the output state of the arithmetic processing unit. , And the upper limit level set corresponding to the saturation level of the amplifying means for amplifying the pair of position signals respectively, and at least the signal level of one of the position signals is compared, and the signal level is compared. upper limit Comparing the first comparing means for generating an output when the signal exceeds the bell with the lower limit level set corresponding to the minimum necessary level for signal processing and the signal level of one designated position signal. Second comparing means for generating an output when the signal level becomes equal to or lower than the lower limit level,
An analog output characterized by comprising display control means for switching the emission color of the operation indicator lamp to a color different from that when the output state of the arithmetic processing section is displayed when an output is generated from one of the comparison means. Distance measuring photoelectric sensor. 3. The lower limit level is multiplied by a predetermined margin value to set a margin level larger than the lower limit level and smaller than the upper limit level, and the margin level is compared with the signal level of one designated position signal. Third comparing means for comparing and detecting to generate an output when the signal level exceeds a margin level;
3. The margin display means for displaying that there is an output from the third comparison means and the first comparison means is in a stable state when no output is generated, the margin display means is provided. Analog output ranging photoelectric sensor.