JP3169839B2 - Automatic sensor sensitivity adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an automatic sensitivity adjusting device for a sensor.

[0002]

2. Description of the Related Art Various sensors are provided on an automatic conveyance line in a factory, and various detections are performed on a conveyed object. In such a sensor,
In order to increase the detection accuracy, it is necessary to adjust the sensitivity in advance. Conventionally, a sample of the detection target is prepared in advance, and the sensitivity is adjusted using the sample. Specifically, the level of each detection signal when the sample is set in the detection area and when the sample is not set are stored, and, for example, an intermediate value between both levels is used as a reference for determining the presence or absence of the detection target. It is set as a value.

[0003]

However, according to the above method, the sample must be manually set or removed (hereinafter, not set) in the detection area, which is not only troublesome but also troublesome. If the area is provided in an internal device that is out of reach, the sample cannot be set there or the like, so that adjustment is impossible.

When the detection area is provided in an internal device that is out of reach, it is conceivable to use a transport line as a method of adjusting the sensitivity. That is, this is a method in which the transport line is moved to set or not set the sample in the detection area. However, since it is difficult to move the transport line while finely adjusting it, much time is spent on the adjustment operation. Further, in this method, since it is necessary to check whether a sample is set in the detection area, it is impossible to set the sample in the detection area unless the detection area is located at a visible position. The present invention
The present invention has been made in view of the above circumstances, and an object thereof is to provide an automatic sensitivity adjustment device for a sensor that can easily perform sensitivity adjustment.

[0005]

To achieve the above object, according to the Invention The automatic sensitivity adjustment apparatus according to claim 1 sensor, the measurement signal detected section or RaIzuru force against the object to be detected that passes through the detection region This is for automatically adjusting the detection sensitivity of a sensor that performs various types of detection based on the detection signal, and stores, as a reference value, a value corresponding to a measurement signal in a state before an object to be detected passes through a detection area. a reference value storing means for, comparing the reference value stored in the reference value <br/> storage means and a value corresponding to the measurement signal, does not change a value corresponding to the predetermined width or more measurement signals after they have different Object determination means for determining that an object is present in the detection area on the condition that the object is present in the detection area; and a sensitivity based on a value corresponding to the measurement signal after the object determination means determines that the object is present in the detection area. And sensitivity adjustment means for performing the adjustment. Rukoto to having the features.

[0006]

According to the first aspect of the present invention, before the detected object passes through the inspection area, a value corresponding to the measurement signal in that state is stored in the reference value storage means as a reference value. Thereafter, the object determination means compares the reference value with the value corresponding to the measurement signal, and detects the object under the condition that the value corresponding to the measurement signal does not change beyond a predetermined width after the difference. It is determined that it is within the area. Then, if the object determining means determines that the object to be detected is within the detection area, the sensitivity adjusting means performs sensitivity adjustment from a value corresponding to the measurement signal. Therefore, the sensitivity can be adjusted simply by passing the detection object through the detection area, so that the sensitivity can be easily adjusted even when the detection area is set in a place where it cannot be reached. In addition, the value corresponding to the measurement signal does not change beyond a predetermined width after they differ from each other, instead of simply comparing the reference value and the value corresponding to the measurement signal to determine that there is an object in the detection area. Since the object is determined to be within the detection area on the condition that
The presence of the object in the detection area is ensured, and the sensitivity can be adjusted more accurately.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> A first embodiment of a sensor automatic sensitivity adjusting device according to the present invention will be described below with reference to FIGS. The automatic sensitivity adjusting device for a sensor according to the present invention is applied to a color sensor that performs color judgment on an object to be detected, and the hardware configuration thereof will be described with reference to the block diagram shown in FIG.

(Hardware Configuration) In FIG. 1, reference numeral 1 denotes a central processing unit (hereinafter referred to as a CPU), in which light emitting elements 2 emitting blue, green, and red light are respectively driven via a driving circuit 3. Connected. Each of the light projecting elements 2 performs a light projecting operation at a constant cycle on an object passing through the detection area.

A light receiving element 4 corresponding to each light emitting element 2
Are provided to receive the reflected light from the object to be detected. An amplifying circuit 5 is connected to the light receiving element 4 so that a light receiving signal (corresponding to a measurement signal in the present invention) output from the light receiving element 4 is amplified. The amplification circuit 5 is configured so that the amplification factor can be varied (six steps), and the amplification factor is controlled by the CPU 1.

At the subsequent stage of the amplifier circuit 5, three analog switches 6, a sample-and-hold circuit 7, and an A / D conversion circuit 8 are provided for each of the emission colors (red, green, and blue). . Then, by opening and closing each analog switch 6 in synchronization with the light projection timing, the received light signal is divided into signals based on red, green, and blue, and each is converted into a digital amount. The light receiving signal (light receiving value) converted into the digital amount is transmitted to the CPU 1
Read by. The sample hold circuit 7
Is 200 μS to 300 μS.

Further, a storage unit 9, an output unit 10, and a display unit 11 are connected to the CPU 1. The storage unit 9 is a ROM
(A read-only memory) and a RAM (random access memory), and a ROM is written with a color determination program for performing color determination on an object to be detected. In the RAM, the received light value read from the A / D conversion circuit 8, the background saturation range in a background color range setting routine described later, and the like are written. This R
Part of the AM corresponds to the reference value storage means of the present invention. The output unit 10 is a circuit that outputs, as a detection signal, a result of color determination on an object to be detected by the color determination program. The display unit 11 includes a plurality of LEDs and the like, and displays an operation state such as a state where color determination is being performed.

The teaching switch SW1, the rotary switch SW2, and the output inversion switch SW3 are further connected to the CPU1. Teaching switch SW
Reference numeral 1 denotes a switch for executing an automatic sensitivity setting routine described later. The teaching switch S
W1 is a push switch, which is always kept in an off state, and the on state is latched by a latch circuit (not shown) by a pushing operation. A rotary switch SW2 is a switch for determining whether or not to perform brightness determination in the color determination program (brightness determination mode when on)
And allowable values a2 and a2 for the background saturation range and the background lightness range in the background color range setting routine described later.
It is also a switch indicating a3. The output inversion switch SW3 is a switch for inverting the signal level of the detection signal output from the output unit 10 based on the color determination result.

(Color Determination Program) The color determination program will be described with reference to the flowchart shown in FIG. First,
It is determined whether or not the teaching switch SW1 is turned on. If not, the determination is repeated until the teaching switch SW1 is turned on (S
1). If the teaching switch SW1 is turned on, an automatic sensitivity setting routine is executed (S2). Thus, the red judgment range (Xr-, Xr +) and the green judgment range (Xg
-, Xg +), a blue judgment range (Xb-, Xb +), and a lightness judgment range (Y-, Y +). Xr- indicates the lower limit of the red determination range, and Xr + indicates the upper limit of the red determination range. Hereinafter, the lower limit value and the upper limit value of Xg-, Xg +, Xb- and Xb + are also shown. Note that the saturation determination range includes the red determination range, the green determination range, and the blue determination range.

Subsequently, the received light value is read (S3). That is, the light receiving signal converted into a digital amount by the A / D conversion circuit 8 is read. Here, among the read light receiving values, the light receiving value corresponding to red is R, the light receiving value corresponding to green is G, and the light receiving value corresponding to blue is B. Then, based on the received light values R, G, B, the saturation values (red saturation value, green saturation value, blue saturation value) Sr, Sg, Sb of the object to be detected.
Is determined, and it is determined whether each of the saturation values Sr, Sg, Sb is in the following range (S4). That is, it is determined whether or not each saturation value of the detected object is the same as the color sample. Xr- <Sr <Xr + Xg- <Sg <Xg + Xb- <Sb <Xb +

Red saturation value Sr, green saturation value Sg, blue saturation value S
b is obtained by the following calculation. The following red saturation values S0r, S1r, S2r, green saturation values S1g, S2g, S3g, and blue saturation values S1b, S2b, S3b are similarly obtained from the corresponding light receiving values by the following calculation. Each of the saturation values corresponds to a value corresponding to the measurement signal according to the present invention. Sr = R / (R + G + B) Sg = G / (R + G + B) Sb = B / (R + G + B)

The red saturation value Sr, green saturation value Sg, and blue saturation value Sb of the object to be detected are respectively in the red determination range (Xr-, Xr
+), Green judgment range (Xg-, Xg +), blue judgment range (Xb
If it is not within (−, Xb +), it is determined whether or not the output inversion switch SW3 is turned on (S5). If the output inversion switch SW3 is on, the output unit 10 outputs a high-level detection signal. (S6) If it is off, a low-level detection signal is output (S10).

On the other hand, if the saturation values Sr, Sg, Sb are not within the saturation determination ranges Xr, Xg, Xb in S4, the condition is that the rotary switch SW2 is turned on (brightness determination mode) (S7). It is determined whether or not the brightness value M is within the brightness determination range (Y-, Y +) as shown below (S
8). Y- <M <Y +

The lightness value M for the object to be detected is represented by a light reception value R,
G and B are obtained by the following calculation. The following lightness values M1 and M3 are similarly obtained from the corresponding light receiving values by the following calculation. M = R + G + B

Then, the brightness value M falls within the brightness determination range (Y-,
If it is within Y +), it is determined whether or not the output inversion switch SW3 is turned on (S9), and if it is on, the output unit 10 outputs a low-level detection signal (S10).
If it is off, a high-level detection signal is output (S
6). In S8, the lightness value M falls within the lightness determination range (Y
, Y +), a detection signal is output in accordance with S5. In other words, in the determination of only the saturation, when only the brightness is different, such as white and black, this cannot be determined. In such a case, the rotary switch SW is used.
2 is turned on to determine the brightness.

Hereinafter, the relationship between the determination result and the detection signal will be described. Saturation (red, green, blue) Lightness SW2 SW3 Detection signal difference--ON high difference--OFF low same-OFF ON low same-OFF OFF high same ON ON high same different ON OFF low Same as ON ON low same ON OFF High

After outputting the detection signal based on the determination result, it is further determined whether or not the teaching switch SW1 is turned on. If the teaching switch SW1 is turned on, the process returns to S2 to execute the automatic sensitivity setting routine again, and , Color determination for the next received light values R, G, B. When the teaching switch SW1 is turned off, the color determination for the next received light values R, G, B is performed without repeating the execution of the automatic sensitivity setting routine.

(Automatic Sensitivity Setting Routine) The automatic sensitivity setting routine will be described with reference to the flowchart shown in FIG. The automatic sensitivity setting routine is a subroutine for setting the saturation judgment range and the lightness judgment range, and a color sample is used as an object to set the saturation judgment range and the lightness judgment range. Here, since the teaching switch SW1 is pressed before the color sample is conveyed into the detection area, the background color range setting routine is first executed based on the state where the color sample is not in the detection area (S
100). Then, an object determination routine (corresponding to the object determination means of the present invention) for determining whether or not the color sample is within the detection area is executed (S200). Further, when it is determined by the object determination routine that the color sample is within the detection area, a sensitivity adjustment routine (corresponding to the sensitivity adjustment unit of the present invention) (S300) is executed.

(Background color range setting routine) The background color range setting routine will be described with reference to the flowchart shown in FIG. First, the amplification factor A for the amplifier circuit 5 is minimized (S101). Then, the received light values R0, G0, B0 are read (S101), and it is determined whether at least one of the received light values R0, G0, B0 is within a predetermined level range (S102).

If all of the received light values R0, G0, B0 are not within the predetermined level range, it is determined whether or not the amplification factor A is already maximum (S103). Is increased by one so that at least one of the received light values R0, G0, B0 is within a predetermined level range (S
104, S105). That is, the amplification factor of the amplifier circuit 5 is adjusted so that the light receiving level with respect to the background becomes optimal according to the environment and the like.

If at least one of the received light values R0, G0, B0 is adjusted to be within a predetermined level range, the amplification factor A is substituted for α0 (S106), and the allowable value a1 corresponding to the value of α0 is obtained. Is read from the table in the storage unit 9. Further, the permissible value a2 is read from the rotary switch SW2 (S107). Then, the received light values R0, G0, B
The background red range (Br-, Br +), the background green range (Bg-, Bg +), and the background blue range (Bb-, Bb +) are calculated from 0 and the allowable values a1, a2 as follows, and the calculation results are stored. It is stored in the unit 9 (S108). Here, Br- indicates the lower limit of the background red range, and Br + indicates the upper limit of the background red range.
Hereinafter, the lower limit and the upper limit of the respective ranges are also shown for Bg-, Bg +, Bb-, and Bb +. Note that this background red range,
The background green range and the background blue range correspond to the reference values of the present invention.
The background saturation range includes the background red range, the background green range, and the background blue range. Br− = R0 / ｛(R0 + G0 + B0) − (a1 + a2
)｝ Br + = R0 / ｛(R0 + G0 + B0) + (a1 + a2)
)｝ Bg− = G0 / ｛(R0 + G0 + B0)-(a1 + a2)
)｝ Bg + = G0 / ｛(R0 + G0 + B0) + (a1 + a2
)｝ Bb− = B0 / ｛(R0 + G0 + B0)-(a1 + a2)
)｝ Bb + = B0 / ｛(R0 + G0 + B0) + (a1 + a2)
Here, the reason why the allowable values a1 and a2 are added or subtracted in each range is to consider white noise and the like accompanying a change in the amplification factor.

Further, it is determined whether or not the rotary switch SW2 is turned on (brightness determination mode) (S2).
109) If it is turned on, the permissible value a3 is read from the rotary switch SW2, and the light receiving values R0, G0,
From B0 and the allowable values a1 and a3, the background lightness range (C-, C +
) Is calculated by the following calculation, and the calculation result is stored in the storage unit 9.
(S110). C- indicates the lower limit of the background lightness range, and C + indicates the upper limit of the background lightness range. C- = R0 + G0 + B0- (a1 + a3) C + = R0 + G0 + B0 + (a1 + a3)

(Object Determination Routine) The object determination routine will be described with reference to the flowcharts shown in FIGS. The received light values R1, G1, and B1 are read (S20).
1). Saturation value S1 based on each received light value R1, G1, B1
r, S1g, and S1b are determined, and it is determined whether or not the saturation values S1r, S1g, and S1b are within the background saturation range (S20).
2). That is, it is detected whether or not the color sample has been conveyed into the detection area. Specifically, it is determined whether it is within the following range. Br- <S1r <Br + Bg- <S1g <Bg + Bb- <S1b <Bb +

If each of the saturation values S1r, S1g, S1b is not within the background saturation range, it is determined that the color sample has been conveyed into the detection area. On the other hand, the saturation values S1r, S1g,
If S1b is within the background saturation range, it is determined whether or not the rotary switch SW2 is turned on (brightness determination mode) (S203).
Lightness M1 is determined from 1, G1, B1 and it is determined whether or not it is within the background lightness range (S204). That is, in the determination of only the saturation value, since different colors such as white and black are determined to be the same, the brightness is further determined to determine this. Specifically, it is determined whether it is within the following range. C- <M1 <C + Then, even when the lightness M1 is not within the background lightness range (C-, C +), it is determined that the color sample has been conveyed into the detection area.

Subsequently, after it is determined that the color sample has been conveyed into the detection area, the received light values R1, G1, B at that time are determined.
It is determined whether or not at least one of them is within a predetermined level range (S205). If all of the received light values R1, G1, and B1 are not within the predetermined level range, while adjusting the amplification factor A, newly read the received light values R1, G1, and B1 so that at least one of them is within the predetermined level range. (S206, S207). That is, the amplification factor is adjusted so that the light receiving level for the color sample becomes optimal according to the environment and the like.

If at least one of the received light values R1, G1, B1 falls within a predetermined level range, the amplification factor A at that time is set to α1
(S208), and an allowable value a4 corresponding to the value of α1 is read from the table of the storage unit 9,
From these values, the object red confirmation range (Tr-, Tr +), the object green confirmation range (Tg-, Tg +), and the object blue confirmation range (Tb-,
Tb +) is obtained and stored in the storage unit 9 (209).
Here, the reason for setting such a range is to repeatedly determine whether or not a color sample has been further conveyed into the detection area thereafter. That is, since the light receiving signal is in an extremely unstable state at the edge portion of the color sample, the above-described determination alone (S202, S204) lacks reliability.
Therefore, in order to increase the reliability of the determination result, an object red confirmation range and the like are set, and thereafter, the determination operation is repeated. Here, Tr- indicates the lower limit of the object red confirmation range,
Tr + indicates the upper limit. Hereinafter, Tg-, Tg +, Tb-, Tb +
Also shows the upper and lower limits, respectively. The target object saturation check range including the target object red check range, the target object green check range, and the target object blue check range is equivalent to the “predetermined width” in the present invention. Tr− = R1 / (R1 + G1 + B1) −a4｝ Tr + = R1 / ｛(R1 + G1 + B1) + a4｝ Tg− = G1 / (R1 + G1 + B1) −a4｝ Tg + = G1 / G1 / ｛(R1) + A4｝ Tb- = B1 / (R1 + G1 + B1) -a4｝ Tb + = B1 / ｛(R1 + G1 + B1) + a4｝

First, the received light values R2, G2, B2 are read (S210), and it is determined whether or not the saturation values S2r, S2g, S2b based on the received light values R2, G2, B2 are within the object confirmation range. Perform (S211). Specifically, the determination is made as follows. Tr- <S2r <Tr + Tg- <S2g <Tg + Tr- <S2b <Tb +

Further, if the saturation values S2r, S2g, S2b are within the object confirmation range, the received light values R3, G3, B3 are read continuously (S212), and the saturation based on the received light values R3, G3, B3 is obtained. It is determined whether the values S3r, S3g, S3b are within the object confirmation range (S213). If the light reception values R2, G2, B2 or the light reception values R3, G3, B3 are determined to be out of the target object saturation range in S211 and S213,
The above operation is repeated from S201 again. If the received light value is outside the background saturation range and then continuously within the object confirmation range, the received light values R3, G3, and B3 are stored in the storage unit 9 (S214). That is, for the first time, it is determined that the color sample is within the detection area, and a light reception value necessary for sensitivity adjustment described later is captured.

Thereafter, the amplification factor α0 for the background is compared with the amplification factor α1 for the color sample (S215). If they are the same, the received light values R3,
Saturation values S3r, S3g, S3b and lightness value M3 based on G3, B3
It is determined whether or not is within the background saturation range or the background lightness range (S216 to S218). If not within the background saturation range and the background lightness range, the object determination routine ends. That is, here, the comparison with the background color is performed again to determine whether the above determination is correct.

(Sensitivity Adjustment Routine) The sensitivity adjustment routine will be described with reference to the flowchart shown in FIG. If the object is determined to be in the detection area by the object determination routine, the received light values R3, G stored in the storage unit 9 are stored.
3 and B3, the red determination range (Xr-, Xr-
r +), green judgment range (Xg-, Xg +), blue judgment range (Xb-,
Xb +) and the brightness determination range (Y−, Y +) are set (S301, S302). The red judgment range, the green judgment range, the blue judgment range, and the lightness judgment range correspond to the sensitivity of the present invention. Xr− = R3 / ｛(R3 + G3 + B3) -a4｝ Xr + = R3 / ｛(R3 + G3 + B3) + a4｝ Xg− = G3 / ｛(R3 + G3 + B3) -a4｝ Xg + = G3 + ｛3 / ｛(R3) + A4｝ Xb- = B3 / ｛(R3 + G3 + B3) -a4｝ Xb + = B3 / ｛(R3 + G3 + B3) + a4｝ Y + = (R3 + G3 + B3)-(a1 + a3 + Y3) + (R3 + G3 + B3) (A1 + a3)

FIG. 8 is a waveform diagram showing a light receiving signal. In the figure, a indicates a light receiving signal in a state where no color sample exists in the inspection area. The background saturation range and the background lightness range are set based on the light receiving values in this state (S101 to S11).
0).

When the color sample approaches the inspection area, the light receiving signal changes according to the color sample (b in the figure). Then, this change causes the received light value to be out of the background saturation range, so that it is determined that the color sample is approaching the inspection area (S201 to S204). Thereafter, the amplification factor is adjusted (c in the figure) (S205 to S20).
7). Then, the object confirmation range is set, and as shown in d in the figure, if the saturation value is continuously within the object confirmation range, the saturation determination range and the lightness determination range are set (S3).
01, S302).

As described above, in this embodiment, the sensitivity (saturation determination range and lightness determination range) can be adjusted only by passing an object to be detected (color sample) through the detection area. This eliminates the need for manual work for setting a sample or the like in the detection area, and allows easy sensitivity adjustment even when the detection area is not reachable. Moreover, after determining that the object is approaching the detection area, it is further determined that the object is within the detection area on condition that the saturation value is further continuous in the object confirmation range, that is, Since the object is determined to be within the detection area on the condition that the degree value does not change by a predetermined width or more, the determination that the object is within the detection area can be determined with certainty. The adjustment can be performed more accurately. When the color sample is passed through the inspection area, sensitivity adjustment is performed, and at the same time, color determination is performed on the color sample based on the adjusted sensitivity. Therefore, there is no need to pass the actual object to the inspection area after the sensitivity adjustment to determine whether or not the sensitivity adjustment is appropriate, and quick post-processing for the sensitivity adjustment can be performed.

<Second Embodiment> Hereinafter, a second embodiment of the sensor automatic sensitivity adjusting device according to the present invention will be described with reference to FIGS. In the present embodiment, the sensor automatic sensitivity adjustment device of the present invention is applied to a photoelectric sensor. The hardware configuration will be described based on the block diagram shown in FIG.

(Hardware Configuration) In FIG.
U, and a light projecting element 22 that performs a light projecting operation on an object to be detected is connected to the CPU 21 via a drive circuit 23. Further, a light receiving element 24 for receiving the reflected light from the detection object is provided, and the light receiving element 24 is connected to the CPU 2 via an amplifier circuit 25 and an A / D conversion circuit 26.
1 connected. Further, the CPU 21 has a storage unit 27 in which an object detection program for performing object detection on an object to be detected is written, an output unit 28 that outputs a detection signal based on the detection result, and an automatic sensitivity setting routine. The teaching switch SW1 is connected. Note that the storage unit 27 corresponds to a reference value storage unit of the present invention. The teaching switch SW1 is a push switch as in the first embodiment.

(Object Detection Program) FIG. 10 shows a flowchart of the object detection program. First, it is determined whether or not the teaching switch SW1 is turned on (Q1). When the teaching switch SW1 is turned on, an automatic sensitivity setting routine described later is executed (Q2).

Thereafter, the received light value D is read (Q3), and it is determined whether or not the received light value D is equal to or larger than the threshold value X (Q
4). If the threshold value X is exceeded, the output unit 28 outputs a detection signal (Q5), and if it is smaller than the threshold value X, the detection signal is not output (Q6). That is, the object is detected by determining whether or not the light receiving value D is equal to or more than the threshold value X. In the present embodiment, the received light value corresponds to a value corresponding to the measurement signal according to the present invention.

Subsequently, it is determined whether or not the teaching switch SW1 is turned on (Q7). If the teaching switch SW1 is turned on, the automatic sensitivity setting routine is executed again, and the next light reception value D is determined. If not, the next light reception value D is determined without executing the automatic sensitivity setting routine.

(Automatic Sensitivity Setting Routine) The automatic sensitivity setting routine is executed based on a reference sample as an object to be detected, as in the first embodiment. First, a reference range setting routine for setting a reference range based on a state where the reference sample is not in the inspection area is executed (Q10).
0). Subsequently, an object determination routine (corresponding to the object determination means of the present invention) for determining whether or not the reference sample is within the detection area based on the reference range is executed (Q200). If it is determined that the reference sample is within the detection area, the threshold value X is obtained from the received light value D0 and the received light value D1 read by the reference range setting routine and the object determination routine as follows (Q30).
0). X = (D0 + D1) / 2 That is, the threshold value X is set between the light receiving value D0 when there is no reference sample in the inspection area and the light receiving value D1 when there is a reference sample in the inspection area. The setting of the threshold value X corresponds to the sensitivity adjusting means of the present invention.

(Reference range setting routine) When the reference sample is not in the inspection area, the received light value D0 is read (Q101), and the allowable value a corresponding to the received light value D0 is read from the table in the storage unit 27 (Q102). . Then, the reference range (B−, B +) is calculated as follows, and the calculation result is stored in the storage unit 28 (Q103). B- indicates the lower limit of the reference range, and B + indicates the upper limit of the reference range. This reference range corresponds to the reference value according to the present invention. B− = D0−a B + = D0 + a

(Object determination routine) The received light value D1 is read (Q201). Then, it is determined whether or not the received light value D1 is within the reference range (B-, B +) (Q20).
2). If the received light value D1 is not within the reference range, it is determined that the reference sample has reached the inspection area, and the object confirmation range (T−, T +) is determined as follows in order to perform a discriminating operation for confirming that. Storage unit 2
7 (Q203). T- indicates the lower limit of the object confirmation range, and T + indicates the upper limit of the object confirmation range. T− = D1−a T + = D1 + a

Subsequently, the received light value D2 is read (Q20).
4) The received light value D2 is the object confirmation range (T-, T +).
It is determined whether it is within the range (Q205), and the received light value D2
If is not within the object confirmation range, the process returns to Q201 and the received light value
Read 1

The received light value D2 is within the object confirmation range (T−, T +).
), The received light value D3 is further read (Q20).
6) The received light value D3 is the object confirmation range (T-, T +).
It is determined whether or not it is within (Q207). If the received light value D3 is not within the object confirmation range, the process returns to Q201 to read the received light value D1. If the received light value D3 is within the object confirmation range, it is first determined that the reference sample is within the detection area, and the determination operation for confirmation is terminated.

FIG. 14 shows a timing chart of the light receiving signal and the like. In the figure, a is a state where the sample is not in the detection area, b is a state where the sample is approaching the detection area, and c is a state where the reference sample has completely entered the detection area. The reference range is set from the received light value in the state a (Q101 to Q103). At t1, the light receiving signal changes, so that it is determined that the reference sample has approached the inspection area, and then the object confirmation range (T-, T +) is set (Q2).
01 to Q203).

Since the light reception value is not within the object confirmation range from t1 to t1, the light reception value is repeatedly read in the object determination routine. And t3, t4, t
Since the received light value continuously falls within the object confirmation range in step 5, the threshold X, which is the detection sensitivity, is set here for the first time (Q
300). Thereafter, at t6, the received light value is determined based on the set threshold value X (Q4), and the received light value is
If so, a detection signal is output (Q5).

As described above, in the present embodiment, the sensitivity (threshold value X) can be adjusted only by passing the object to be detected (reference sample) through the detection area. This eliminates the need for manual work or the like for setting in the area, so that the sensitivity can be easily adjusted even when the detection area cannot be reached. Moreover, after it is determined that the object is approaching the detection area, the received light value is changed to the object confirmation range (T-
, T +), it is determined that the object is within the detection region on condition that the object is within the detection region on condition that the received light value does not change more than a predetermined width. Since the determination is made, the determination of the presence or absence of the detection object can be made surely, so that the sensitivity adjustment can be performed more accurately. When the reference sample is passed through the inspection area, sensitivity adjustment is performed, and at the same time, object detection is performed on the reference sample based on the adjusted sensitivity.
Therefore, there is no need to pass the actual object to the inspection area after the sensitivity adjustment to determine whether or not the sensitivity adjustment is appropriate, and quick post-processing for the sensitivity adjustment can be performed.

It should be noted that the present invention is not limited to the above embodiments, but can be modified as follows, for example, and these embodiments also belong to the technical scope of the present invention. (1) In each of the above embodiments, the sensitivity adjustment is performed when the color sample or the reference sample passes through the detection region once. However, a plurality of samples are prepared and these are passed through the detection region. The sensitivity may be adjusted based on the average value or the maximum value and the minimum value.

(2) The first embodiment may have the following functions. That is, a switch for enabling / disabling the teaching switch SW1 may be provided, and the teaching switch SW1 may be disabled while the transport line is operating. This prevents the teaching switch from being erroneously pressed during the operation of the transport line. Further, a switch may be provided to determine whether the sensitivity adjustment is performed automatically as described above or manually, as in the related art, so that the sensitivity adjustment means can be selected as needed.

(3) In the background color range setting routine of the first embodiment, the background saturation range and the background lightness range are set based on one received light value in a state where the color sample is not in the detection area. Alternatively, a plurality of light reception values may be read in a state where the color sample is not in the detection area, and the background saturation range and the background lightness range may be set from the average value or the like. Similarly, in the reference range setting routine of the second embodiment, a plurality of received light values may be read in a state where the reference sample is not in the detection area, and the reference range may be set from an average value or the like.

(4) Although the second embodiment is applied to a reflection type photoelectric sensor, it can be applied to a transmission type photoelectric sensor. In this case, since the level of the light receiving signal output from the light receiving element is opposite to that of the reflection type,
When an object to be detected is determined in the object detection program, it is determined to be equal to or less than the threshold value.

(5) In each of the above embodiments, the determination as to whether or not the saturation value or the received light value is within the object confirmation range, etc., is implemented by software. May be used.

(6) In each of the above embodiments, when the saturation value or the received light value is continuously within the object confirmation range, it is determined that the color sample or the reference sample is within the detection area. May be determined based on the amount of change.

(7) In each of the above embodiments, an example in which the present invention is applied to a color sensor or a photoelectric sensor has been described.
You may apply to a temperature sensor, a proximity sensor, etc.

(8) In the first embodiment, the sampling period for the light receiving signal is set to 200 μS to 300 μS. However, the present invention is not limited to this. What is necessary is just to set to an appropriate value.

(9) In the above embodiments, the sensitivity adjustment range, the brightness determination range, and the threshold value are adjusted as the sensitivity adjustment. However, the amplification rate in the amplifier circuit or the light projection amount of the light emitting element is adjusted. You may make it.

(10) In each of the above embodiments, the object is determined to be within the detection area if the saturation value or the received light value falls within the object confirmation range three times in succession. It may be the number of times.

(11) In the first embodiment, if the saturation value is continuously within the object confirmation range, the sensitivity (saturation determination range and lightness determination) is determined from the last read light reception values R3, G3, B3. Range), but the sensitivity adjustment is not limited to this, and the sensitivity adjustment is performed by calculating the average value of the received light values (R1, G1, B1 to R3, G3, B3) related to the continuous saturation value within the object confirmation range. The light receiving values (R1, G1) related to the continuous saturation values within the object confirmation range may be obtained.
, B1 to R3, G3, B3) as long as the sensitivity is adjusted based on at least one of them.

(12) In the first embodiment, the object confirmation range is set based on the received light values R1, G1, and B1 after the saturation value and the background saturation range are different. The confirmation range may be set based on the received light values R0, G0, B0 when the color sample is not in the detection area.

(13) In the first embodiment, the object detection means (object detection routine) compares the saturation value with the background saturation range and the like. In this configuration, the presence or absence of an object (color sample) in the detection area is determined by repeatedly determining whether or not the object is within the object confirmation range. However, after the value corresponding to the received light signal is different from the reference value. Alternatively, the configuration may be such that during a predetermined time, the presence or absence of an object to be detected in the detection area is determined based on whether or not a value corresponding to the light receiving signal is within a certain area. The same applies to the object detection means (object detection routine) of the second embodiment.

(14) In each of the above embodiments, the automatic sensitivity setting routine is configured to be executed when the teaching switch SW1 is turned on. However, the teaching switch is not provided, and, for example, a timer unit is used. The automatic sensitivity setting routine may be executed when a predetermined time elapses after the power is turned on or when the sensor is reset.
In addition, the present invention can be implemented with various modifications without departing from the scope.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the entire first embodiment.

FIG. 2 is a flowchart of a color determination program of the embodiment.

FIG. 3 is a flowchart illustrating an automatic sensitivity setting routine of the embodiment.

FIG. 4 is a flowchart showing a background color range setting routine of the embodiment.

FIG. 5 is a flowchart illustrating a first part of an object determination routine according to the fifth embodiment.

FIG. 6 is a flowchart showing a latter part of the object determination routine of the embodiment.

FIG. 7 is a flowchart illustrating a sensitivity adjustment routine of the embodiment.

FIG. 8 is a waveform chart showing a light receiving signal of the embodiment.

FIG. 9 is a block diagram showing the entire second embodiment.

FIG. 10 is a flowchart showing an object detection program of the embodiment.

FIG. 11 is a flowchart showing an automatic sensitivity setting routine of the embodiment.

FIG. 12 is a flowchart showing a reference range setting routine of the embodiment.

FIG. 13 is a flowchart illustrating an object determination routine of the embodiment.

FIG. 14 is a timing chart of the embodiment.

[Explanation of symbols]

 4 ... Light receiving element (detection unit) 9 ... Storage unit (reference value storage unit) 24 ... Light receiving element (detection unit) 28 ... Storage unit (reference value storage unit)

Claims (1)

(57) [Claims] To 1. A sensor for various detection based on the measurement signal detector or RaIzuru force against the object to be detected that passes through the detection region, be one that automatically adjusts the detection sensitivity of the sensor A reference value storage unit that stores, as a reference value, a value corresponding to the measurement signal in a state before the object passes through the detection region; a reference value stored in the reference value storage unit and the measurement signal Object determination means that determines that there is an object in the detection area on the condition that the value corresponding to the measurement signal does not change by a predetermined width or more after they differ, and And a sensitivity adjusting unit configured to perform sensitivity adjustment from a value corresponding to the measurement signal after the object to be detected is determined to be present in the detection area by the object determining unit. Automatic sensitivity adjustment device.