JP2020067373A - Photoelectronic sensor - Google Patents

Abstract

To provide a photoelectronic sensor that can adjust sensitivity without using a variable divisor and can reduce a calculation cost.SOLUTION: A photoelectronic sensor 1 comprises: a light projection unit 10 that projects light designated in a first parameter on a detection area; a light receiving unit 20 that receives light from the detection area at a sensitivity designated in a second parameter; a determination unit 31 that, based on the quantity of received light obtained by the light receiving unit 20, refers to an adjustment magnification table 500 associating the quantity of received light obtained by the light receiving unit with an adjustment magnification for adjusting the quantity of received light to a predetermined target value, and determines the adjustment magnification; and an update unit 32 that updates at least one of the first parameter and second parameter based on the determined adjustment magnification. The photoelectronic sensor is communicably connected to a storage unit 40 that stores the adjustment magnification table.SELECTED DRAWING: Figure 1

Description

  The present invention relates to photoelectric sensors.

  Conventionally, a photoelectric sensor that projects light onto a detection target and receives light reflected from the detection target may detect various detection targets having different reflectances or detection distances. Since the photoelectric sensor changes the intensity of the reflected light depending on the reflectance and the detection distance when detecting various detection objects in this way, the sensitivity is dynamically adjusted in order to input an appropriate amount of light on the light receiving element. Sometimes. Such sensitivity adjustment is used, for example, in a triangulation distance measuring sensor using a one-dimensional image sensor.

  In the sensitivity adjustment as described above, for example, for the exposure time that is one of the parameters of the sensitivity adjustment, the next exposure time d is the previous exposure time c as in the following equation (1) and the light receiving unit of the photoelectric sensor. There is a method of obtaining it by using the magnification of the target value a with respect to the received light amount b in. The exposure time is a period in which the light projecting period and the light receiving period of the photoelectric sensor overlap. In Patent Document 1 below, the next exposure time is calculated as in the following equation (1), and if the received light amount is lower than the target value, the exposure time is increased, and if the received light amount is higher than the target value, exposure is performed. An optical sensor is disclosed that performs sensitivity adjustment processing by reducing the time.

JP, 2013-190378, A

  In the sensitivity adjustment method as described above, the calculation cost may increase because the variable light reception amount is used for division in order to obtain the parameter for the next sensitivity adjustment. Specifically, the sensitivity adjustment method as described above requires an operation using a variable divisor, but a CPU or FPGA used in a circuit of a photoelectric sensor may not include a hardware divider. Since it is large, it takes a relatively long time to obtain the calculation result. Moreover, if an attempt is made to implement a division circuit in FPGA, the circuit scale will increase.

  Therefore, an object of the present invention is to provide a photoelectric sensor that can adjust the sensitivity without using a variable divisor and can reduce the calculation cost.

  A photoelectric sensor according to an aspect of the present invention includes a light projecting unit that projects light specified by a first parameter onto a detection region, and a light receiving unit that receives light from the detection region at a sensitivity specified by a second parameter. Based on the amount of light received by the light receiver, the adjustment ratio is determined by referring to an adjustment ratio table that associates the amount of light received by the light receiver with an adjustment ratio for adjusting the amount of light received to a predetermined target value. A determination unit and an update unit that updates at least one of the first parameter and the second parameter based on the determined adjustment magnification, and is communicably connected to a storage unit that stores an adjustment magnification table. .

  According to this aspect, in the sensitivity adjustment, the photoelectric sensor specifies the first parameter and / or the first parameter for designating the light projected by the light projecting unit based on the fixed adjustment magnification corresponding to the light receiving amount obtained by the light receiving unit. The second parameter designating the sensitivity of the light receiving unit can be updated. Therefore, the photoelectric sensor can update these parameters without using a variable divisor and adjust the amount of light received by the light receiving unit to a predetermined target value. Therefore, the photoelectric sensor can adjust the sensitivity without using a variable divisor, and can reduce the calculation cost.

  In the above aspect, the first parameter includes at least one of a light projection period applied to the light projection of the light projection unit and a light projection intensity by the light projection unit, and the second parameter is applied to the light reception of the light reception unit. At least one of the light receiving period and the light receiving gain of the light receiving unit may be included.

  According to this aspect, in the photoelectric sensor, the sensitivity can be adjusted by the light projecting period and the light projecting intensity in the light projecting unit, and the sensitivity can be adjusted by the light receiving period and the light receiving gain in the light receiving unit. The sensitivity can be adjusted by any means.

  In the above aspect, the adjustment magnification may be a value of a predetermined function having the light receiving amount of the light receiving unit as an argument.

  According to this aspect, the value of the adjustment magnification can be set in the same manner as the magnification (the magnification of the target value a with respect to the received light amount b in the light receiving portion of the photoelectric sensor) which is conventionally obtained each time light is received.

  In the above aspect, when the received light amount obtained by the light receiving unit is within a predetermined range from the minimum value of the received light amount set in the adjustment magnification table, the adjustment magnification may be a fixed value different from the predetermined function. .

  According to this aspect, when the amount of light is insufficient within a predetermined range from the minimum value of the amount of received light, specifically, when the amount of received light is extremely small and the received light waveform cannot be detected, the adjustment ratio is set in the adjustment ratio table. It is possible to use a fixed value that is applied when the amount of light is insufficient. For this reason, it is possible to determine the adjustment magnification by referring to the adjustment magnification table in the same manner as in normal times, without separately providing processing for light quantity shortage and branching.

  In the above aspect, when the received light amount obtained by the light receiving unit is within a predetermined range from the maximum value of the received light amount set in the adjustment magnification table, the adjustment magnification may be a fixed value different from the predetermined function. .

  According to this aspect, even in the case where the light amount is saturated within a predetermined range from the maximum value of the received light amount, it is possible to use, as the adjustment magnification, the fixed value set in the case where the light amount is saturated set in the adjustment magnification table. For this reason, it is possible to determine the adjustment magnification by referring to the adjustment magnification table as in the normal state without separately branching by separately providing a process for light amount saturation.

  In the above aspect, the adjustment scale factor is an integer of a power of 2, and the updating unit divides a value obtained by multiplying the adjustment scale factor by at least one of the first parameter and the second parameter by a power of 2 and has a value obtained by the division. At least one of the first parameter and the second parameter may be updated.

  According to this aspect, it is possible to restore by the process of multiplying in a state where the fractional part is eliminated by setting the adjustment magnification to an integer in advance, and then dividing by a power of 2, that is, the bit shift process, so that the calculation cost is reduced. Can be reduced.

  In the above aspect, the light receiving element of the light receiving unit may be a CMOS sensor element, and the photoelectric sensor may be a distance measuring sensor using a triangulation distance measuring method.

  In the case where the photoelectric sensor is a distance measuring sensor using a triangulation distance measuring method, since the distances of various detection objects having different detection distances are measured, the chances of sensitivity adjustment increase. That is, conventionally, the calculation cost has been increased by a variable divisor at more timings than a sensor that detects the presence or absence of a detection target. For this reason, in the case of the distance measuring sensor, the photoelectric sensor can more effectively reduce the calculation cost by using the fixed adjustment magnification.

  According to the present invention, it is possible to provide a photoelectric sensor capable of adjusting the sensitivity without using a variable divisor and reducing the calculation cost.

It is a schematic block diagram of the photoelectric sensor which concerns on embodiment. FIG. 3 is a schematic diagram for explaining an example of a data structure of the amount of received light according to the embodiment. It is a figure for demonstrating an example of the data structure of the adjustment ratio table which concerns on embodiment. FIG. 7 is a flowchart showing an example of sensitivity adjustment operation of the photoelectric sensor according to the embodiment.

  A preferred embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the accompanying drawings. In addition, in each of the drawings, those denoted by the same reference numerals have the same or similar configurations.

<1. Configuration example>
A configuration example of the photoelectric sensor 1 according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a schematic block diagram of a photoelectric sensor 1 according to the embodiment. The photoelectric sensor 1 according to the present embodiment is, for example, a distance measurement sensor that uses a triangulation distance measurement method for measuring the distance to an object. When the photoelectric sensor 1 is a distance measuring sensor, since the distances of various detection objects having different detection distances are measured, the chances of sensitivity adjustment increase. That is, conventionally, the calculation cost is increased by performing the division by the variable divisor at more timings than the sensor for detecting the presence or absence of the detection target. Therefore, the photoelectric sensor 1 can reduce the calculation cost more effectively by using a fixed adjustment magnification, particularly in the case of the distance measuring sensor. Further, the photoelectric sensor 1 can perform high-speed processing by reducing the calculation cost in this way.

  The photoelectric sensor 1 includes a light projecting unit 10, a light receiving unit 20, a control unit 30, and a storage unit 40. In the case of a reflection type sensor, for example, the photoelectric sensor 1 projects light from the light projecting unit 10 toward an object to be detected, and receives light reflected from the object to be detected by the light receiving unit 20.

  The light projecting unit 10 includes a light projecting element 11 and a light projecting control circuit 12 that drives the light projecting element 11. The light projecting unit 10 projects the light designated by the first parameter onto the detection area. Here, the “first parameter” is a parameter designated for performing light emission control of the light emitting unit 10. The first parameter may include, for example, at least one of a light projection period applied to the light projection of the light projection unit 10 and a light projection intensity by the light projection unit 10. According to such a configuration, the photoelectric sensor can adjust the sensitivity in the light projecting section by the light projecting period and the light projecting intensity, and the sensitivity can be adjusted by various means.

  The light projecting element 11 is an element that projects light onto the detection region. The light projecting element 11 may be, for example, a laser diode, but may also be configured by an element such as a light emitting diode. The light projecting control circuit 12 outputs a drive signal for driving the light projecting element 11 to the light projecting element 11 based on the light projecting command signal including the first parameter from the control unit 30.

  The light receiving section 20 includes a light receiving element 21, a signal processing circuit 22, and an A / D conversion circuit 23. The light receiving unit 20 receives light from the detection region with the sensitivity specified by the second parameter. Here, the “second parameter” is a parameter designated for performing light reception control of the light receiving unit 20. The second parameter may include, for example, at least one of the light receiving period applied to the light receiving of the light receiving unit 20 and the light receiving gain of the light receiving unit 20. With such a configuration, the photoelectric sensor 1 can perform sensitivity adjustment in the light receiving section 20 depending on the light receiving period and the light receiving gain, and can perform sensitivity adjustment using various means.

  The light receiving element 21 is, for example, an image pickup element such as a CMOS sensor element or a CCD sensor element, and may have a shutter function. The signal processing circuit 22 performs processing such as amplification on the received light signal output from the light receiving element 21. The A / D conversion circuit 23 converts the signal output from the signal processing circuit 22 into a digital signal to generate data representing the amount of received light. When the light receiving element 21 is a one-dimensional image pickup element, the light receiving unit 20 searches for pixels arranged in a one-dimensional manner and obtains the peak light amount of the received light amount distribution (hereinafter, simply referred to as “light receiving amount”). When the photoelectric sensor 1 is a distance measuring sensor using the triangulation distance measuring method, the distance to the detection target is measured by the pixel position of this peak.

  The control unit 30 includes a determination unit 31 and an updating unit 32. The control unit 30 executes processing related to measurement of the distance to the detection target and sensitivity adjustment based on a program stored in the storage unit 40 described later. The control unit 30 is composed of, for example, a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array). Note that, according to the present invention, since the calculation cost can be suppressed, the control unit 30 can be implemented by a small-scale CPU or FPGA.

  The determination unit 31 determines the adjustment magnification by referring to the adjustment magnification table based on the amount of received light obtained by the light receiving unit 20. Here, the “adjustment magnification” is a magnification for adjusting the amount of light received by the light receiving unit 20 to a predetermined target value. The photoelectric sensor 1 adjusts the sensitivity by adjusting the received light amount to a predetermined target value by the adjustment magnification. The “adjustment magnification table” is a table that associates the amount of light received by the light receiving unit 20 with the adjustment magnification.

  The configuration of the adjustment magnification table and the method of referring to the adjustment magnification table based on the amount of light received by the light receiving unit 20 will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing an example of a data structure of the amount of light received by the light receiving unit 20. FIG. 3 is a table showing an example of the data structure of the adjustment magnification table 500 according to this embodiment. In this example, the light receiving amount of the light receiving unit 20 used when referring to the adjustment magnification table is the light receiving amount obtained by the pixels arranged one-dimensionally.

  FIG. 2 shows an example of a data structure in which the amount of light received by the light receiving unit 20 is converted into 10-bit binary data by the A / D conversion circuit 23. The determination unit 31 refers to the adjustment magnification table using the value of the upper 5 bits of the converted binary data as a key. Further, since the value of the lower 5 bits of the converted binary data is truncated, the value of the upper 5 bits actually includes a value from the minimum value 503 to the maximum value 504 of the amount of received light with respect to the adjustment magnification described later. There is. For example, when the amount of received light obtained by the light receiving unit 20 is “720”, it becomes “1011010000” when converted into 10-bit binary data. The determination unit 31 acquires the upper 5 bits “10110” of this binary data and discards the lower 5 bits “10000”.

  As illustrated in FIG. 3, the adjustment magnification table 500 includes a No 501, an address 502, a minimum value 503, a maximum value 504, a median value 505, an adjustment magnification (integer) 506, and an adjustment magnification 507. These pieces of information do not need to be all included in the adjustment magnification table 500, and the adjustment magnification table 500 may include information other than these, and may be included in the adjustment magnification determination processing using the adjustment magnification table 500. It may be appropriately set depending on the situation.

  The address 502 is the main key of the adjustment magnification table 500 and is expressed in binary and corresponds to the upper 5 bits of the received light amount. For example, when the upper 5 bits of the received light amount is “10110”, the determination unit 31 determines that the adjustment magnification (integer) 506 “32” of the record whose address 502 is “10110”, that is, the record whose No 501 is “22” or The adjustment magnification 507 “1.00” is referred to.

  The minimum value 503 indicates the minimum value of the amount of received light corresponding to a certain address 502. The minimum value 503 corresponds to the amount of received light in which the lower 5 bits of the value of the address 502 are all “0”. The maximum value 504 indicates the maximum value of the amount of received light corresponding to a certain address 502. The maximum value 504 corresponds to the amount of received light in which the lower 5 bits of the value of the address 502 are all “1”. The median value 505 indicates the median value of the amount of received light corresponding to a certain address 502.

  The adjustment magnification (integer) 506 is an integer obtained by multiplying the value of the adjustment magnification 507 by a power of 2. The adjustment magnification (integer) 506 is, for example, an integer obtained by multiplying the value of the adjustment magnification 507 by 32. By using an integer that is a power of 2 as described above, the updating unit 32, which will be described later, can multiply the received light amount obtained by the light receiving unit 20 by the adjustment magnification in a state in which the fractional part is eliminated. Since the updating unit 32 can restore the original value by a process of dividing by a power of 2, that is, a bit shift process, the operation cost can be reduced.

  The adjustment magnification 507 may be a value of a predetermined function having the light receiving amount of the light receiving unit 20 as an argument. For example, the next exposure time can be obtained by using the conventional method using the previous exposure time and the magnification of the target value with respect to the amount of light received by the light receiving portion of the photoelectric sensor (target value / light receiving amount). Since the adjustment magnification 507 corresponds to the magnification of the target value with respect to the received light amount, it can be obtained by a function using the received light amount as an argument. With such a configuration, the value of the adjustment magnification 507 can be set in the same manner as the magnification (the magnification of the target value with respect to the amount of light received by the light receiving unit of the photoelectric sensor) that is conventionally obtained each time light is received. Note that the exposure time is generally the length of the light receiving period, but when the light projecting period and the light receiving period are different, the two periods overlap. For example, when the light receiving element is a CMOS sensor element and has a shutter function, the exposure time corresponds to the overlap time of the shutter open period of the light receiving element 21 and the light projecting period of the light projecting element 11.

  When the amount of received light obtained by the light receiving unit 20 is within a predetermined range from the minimum value of the amount of received light set in the adjustment magnification table 500, the adjustment magnification 507 may be a fixed value different from the value of the predetermined function. . For example, when the received light amount obtained by the light receiving unit 20 is the minimum value of the received light amount set in the adjustment magnification table 500 or within a predetermined range from the minimum value, specifically, when the received light amount of No 501 is “0” The light receiving section 20 includes a state in which the light receiving waveform cannot be detected and the light amount is insufficient. In such a state of insufficient light amount, the amount of received light cannot be determined, so the adjustment magnification 507 cannot be set using the value of a predetermined function with the amount of received light as an argument. Therefore, as the adjustment magnification applied to such a state of insufficient light quantity, the adjustment magnification 507 may be set to a fixed value (for example, 10 times) different from the value of the predetermined function.

  Conventionally, the process is branched depending on whether the received light amount is within a predetermined range from the minimum value, and when the received light amount is within the predetermined range from the minimum value, the adjustment magnification is set to a fixed value such as 10 times. When the amount of received light is not within the predetermined range from the minimum value, the adjustment magnification is calculated by, for example, the mathematical expression (1). However, if the processing is branched according to the amount of received light, the calculation load will increase. In this respect, in the photoelectric sensor 1 according to the present embodiment, the determination unit 31 has the above-described configuration even when the amount of received light is insufficient within a predetermined range from the minimum value of the amount of received light, specifically, when the amount of received light is extremely small. The adjustment magnification can be determined by referring to the adjustment magnification table as in the normal state without separately providing a process for the insufficient light amount and branching. As a result, the photoelectric sensor 1 can be given a characteristic with a high degree of freedom by means of the adjustment magnification table, so that the sensitivity adjustment convergence time when the light quantity is insufficient can be optimized.

  When the amount of received light obtained by the light receiving unit 20 is within a predetermined range from the maximum value of the amount of received light set in the adjustment magnification table, the adjustment magnification 507 may be a fixed value different from the value of the predetermined function. For example, when the received light amount obtained by the light receiving unit 20 is the maximum value of the received light amount set in the adjustment magnification table 500 or within a predetermined range from the maximum value, specifically, when the received light amount of No 501 is “31” A state in which the light receiving waveform is saturated in the light receiving unit 20 is included. In such a light amount saturation state, since the received light amount cannot be determined, the adjustment magnification 507 cannot be set using the value of a predetermined function having the received light amount as an argument. Therefore, in the adjustment magnification applied to such a saturated light amount state, the adjustment magnification 507 may be set to a fixed value (eg, 0.1 times) different from the value of the predetermined function.

  Conventionally, processing is branched depending on whether the received light amount is within a predetermined range from the maximum value, and when the received light amount is within a predetermined range from the maximum value, the adjustment magnification is fixed to 0.1 times or the like. As the value, when the received light amount is not within the predetermined range from the maximum value, the adjustment magnification is calculated by, for example, the mathematical expression (1). However, if the processing is branched according to the amount of received light, the calculation load will increase. In this regard, in the photoelectric sensor 1 according to the present embodiment, with the above configuration, when the light amount saturation is within the predetermined range from the maximum value of the received light amount, the determination unit 31 does not perform branching by separately providing a process for the light amount saturation. The adjustment magnification can be determined by referring to the adjustment magnification table as in the case of the above. As a result, the photoelectric sensor 1 can be given a characteristic with a high degree of freedom by the adjustment magnification table, so that the sensitivity adjustment convergence time at the time of light amount saturation can be optimized.

  The description will be continued with reference to FIG. 1 again. The updating unit 32 updates at least one of the first parameter and the second parameter based on the adjustment magnification determined by the determining unit 31. According to such a configuration, the updating unit 32 uses the first parameter and / or the light receiving unit that specifies the light to be emitted by the light emitting unit, based on the fixed adjustment magnification corresponding to the light receiving amount obtained by the light receiving unit. A second parameter specifying the sensitivity of the part can be updated. Therefore, the photoelectric sensor 1 can update these parameters without using a variable divisor and adjust the amount of light received by the light receiving unit to a predetermined target value. Therefore, the photoelectric sensor 1 can adjust the sensitivity without using a variable divisor, and can reduce the calculation cost.

  When the adjustment ratio is an integer power of 2, the updating unit 32 divides a value obtained by multiplying the adjustment ratio by at least one of the first parameter and the second parameter by a power of 2 and uses the divided value as the first value. At least one of the parameter and the second parameter may be updated. For example, when the adjustment ratio is an integer multiplied by 32, the updating unit 32 may update the first parameter and / or the second parameter by multiplying the first parameter by the adjustment ratio and then shifting by 5 bits. .

  Specifically, the updating unit 32 determines the next exposure time d as the adjustment magnification e determined based on the previous exposure time c and the light reception amount b in the light receiving unit of the photoelectric sensor as shown in the following equation (2). And a fixed value f of a power of 2 may be used. As the adjustment magnification e, the value of the adjustment magnification (integer) 506, which is an integer obtained by previously multiplying the value of a predetermined function or the fixed value of the adjustment magnification 507 by a power of 2, is used.

  According to the above configuration, the updating unit 32 can restore the original value by the process of multiplying in a state where the fractional part is eliminated by setting the adjustment magnification to an integer in advance and then dividing by a power of 2, that is, the bit shift process. . That is, if the fixed value to be divided is a power of 2, the division by the fixed value can be substituted by the bit shift process. Therefore, the updating unit 32 can reduce the calculation cost in updating the first parameter and / or the second parameter.

  The updating unit 32 mainly updates the exposure time in the sensitivity adjustment, but when the adjustment exceeding the adjustment range of the exposure time is necessary, the light emitting intensity of the light emitting unit 10 or the light receiving gain of the light receiving unit 20 (light receiving unit). The amplification factor in 20) may be updated. For example, if the received light amount is saturated even when the exposure time is set to the lower limit value, the update unit 32 lowers the light projection intensity and the received light gain, and sets the exposure time to the upper limit value to obtain a sufficient received light amount. When the intensity does not become high, the light emission intensity and the light receiving gain may be updated. With such a configuration, the photoelectric sensor can perform sensitivity adjustment by various means according to a plurality of parameters such as exposure time (light emitting period and / or light receiving period), light emitting intensity, or light receiving gain in sensitivity adjustment. .

  The storage unit 40 stores an adjustment magnification table. In addition, the storage unit 40 may store a program that executes processing relating to measurement of the distance to the detection target and sensitivity adjustment. Further, the storage unit 40 is connected to the photoelectric sensor 1 so as to be able to communicate therewith. That is, the storage unit 40 may be provided inside the photoelectric sensor 1 or outside the photoelectric sensor 1 as long as the storage unit 40 is communicably connected to the control unit 30 inside the photoelectric sensor 1.

<2. Operation example>
An operation example of sensitivity adjustment of the photoelectric sensor 1 according to the present embodiment will be described with reference to FIG. In this example, an example in which the sensitivity process is always executed during the operation of the photoelectric sensor 1 will be described. Note that, as another example, the photoelectric sensor 1 may manually start / end the sensitivity adjustment process according to an instruction from the user, or the detected light receiving amount is within a predetermined range of the target value. If so, the sensitivity adjustment processing may be automatically terminated.

  As shown in FIG. 4, the light projecting unit 10 projects the light designated by the first parameter onto the detection area (S10). The light receiving unit 20 receives the light projected from the detection area with the sensitivity specified by the second parameter (S11). The light receiving unit 20 detects the light receiving amount which is the maximum peak in the light receiving amount distribution (S12).

  The determination unit 31 determines the adjustment magnification by referring to the adjustment magnification table based on the amount of light received by the light receiving unit 20 (S13). The updating unit 32 updates at least one of the first parameter and the second parameter based on the determined adjustment magnification (S14). The photoelectric sensor 1 ends the sensitivity adjustment process when the power is off (Yes in S15). When the power source is ON (No in S15), the photoelectric sensor 1 returns to the state before step S10, and performs the sensitivity adjustment process again with the updated first parameter and / or second parameter.

  The embodiments described above are for facilitating the understanding of the present invention and are not for limiting the interpretation of the present invention. Each element included in the embodiment and its arrangement, material, condition, shape, size and the like are not limited to the exemplified ones and can be appropriately changed. Further, the configurations shown in different embodiments can be partially replaced or combined.

  The whole or part of the exemplary embodiment can be described as, but not limited to, the following supplementary notes.

[Appendix]
A light projecting section (10) for projecting the light designated by the first parameter to the detection region;
A light receiving section (20) for receiving the light from the detection region with a sensitivity designated by a second parameter,
Based on the amount of light received by the light receiving unit (20), an adjustment magnification table that associates the amount of light received by the light receiving unit (20) with an adjustment magnification for adjusting the amount of light received to a predetermined target value. A determination unit (31) for determining the adjustment magnification with reference to (500),
An update unit (32) for updating at least one of the first parameter and the second parameter based on the determined adjustment magnification,
Connected to a storage unit (40) that stores the adjustment magnification table (500) in a communicable manner,
Photoelectric sensor (1).

  DESCRIPTION OF SYMBOLS 1 ... Photoelectric sensor, 10 ... Emitting part, 11 ... Emitting element, 12 ... Emitting control circuit, 20 ... Light receiving part, 21 ... Light receiving element, 22 ... Signal processing circuit, 23 ... A / D conversion circuit, 30 ... Control unit, 31 ... Judgment unit, 32 ... Update unit, 40 ... Storage unit

Claims (7)

A light projecting unit for projecting the light designated by the first parameter to the detection region;
A light-receiving unit that receives the light from the detection region with a sensitivity specified by a second parameter,
On the basis of the amount of light received by the light receiving unit, the adjustment magnification is referred to by referring to an adjustment magnification table that associates the amount of light received by the light receiving unit with an adjustment magnification for adjusting the amount of light received to a predetermined target value. A determination unit for determining,
An updating unit that updates at least one of the first parameter and the second parameter based on the determined adjustment magnification,
A storage unit that stores the adjustment magnification table is communicably connected to the storage unit.
Photoelectric sensor. The first parameter includes at least one of a light projection period applied to the light projection of the light projection unit and a light projection intensity by the light projection unit,
The second parameter includes at least one of a light receiving period applied to light reception of the light receiving unit and a light receiving gain of the light receiving unit,
The photoelectric sensor according to claim 1. The adjustment magnification is a value of a predetermined function with the light receiving amount of the light receiving unit as an argument,
The photoelectric sensor according to claim 1. When the amount of received light obtained by the light receiving unit is within a predetermined range from the minimum value of the amount of received light set in the adjustment magnification table, the adjustment magnification is a fixed value different from the value of the predetermined function. ,
The photoelectric sensor according to claim 3. When the amount of received light obtained by the light receiving unit is within a predetermined range from the maximum value of the amount of received light set in the adjustment magnification table, the adjustment magnification is a fixed value different from the value of the predetermined function. ,
The photoelectric sensor according to claim 3 or 4. The adjustment ratio is an integer power of 2,
The update unit divides a value obtained by multiplying at least one of the first parameter and the second parameter by the adjustment scale factor by a power of 2, and uses the divided value as a value of the first parameter and the second parameter. Update at least one,
The photoelectric sensor according to any one of claims 1 to 5. The light receiving element of the light receiving unit is a CMOS sensor element,
The photoelectric sensor is a distance measuring sensor using a triangular distance measuring method.
The photoelectric sensor according to any one of claims 1 to 6.