JPH0540896U - Detection switch device - Google Patents

Abstract

(57) [Summary] [Purpose] Automatically sets the judgment level and notifies whether or not detection can be performed reliably. [Structure] When the first and second setting switches 9 and 10 are operated, the microcomputer 1 executes a detection program (main program) and a gain setting program to generate a light reception signal depending on the presence or absence of an object to be detected. The levels are stored and the light receiving gain of the light receiving gain variable circuit 8 is set according to the levels. Further, the microcomputer 1 outputs an alarm signal to the alarm output transistor 20 and outputs the alarm display LED 1 when the level difference between the stored light receiving signals is smaller than the set margin value.
Turn on 3. On the other hand, when it is larger than the margin value, the margin value for the ambient light or noise is exceeded in the setting state, so that the detection can be reliably performed, so that it is not necessary to actually perform the test using the object to be detected.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

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

[0002]

[Prior Art]

 A photoelectric switch, which is an example of this type of detection switch device, is provided with a light projecting unit that irradiates the detected area with light and a light receiving unit that receives the reflected light from the detected area. The presence / absence of an object is detected by determining whether or not the level of the detection signal corresponding to the above exceeds a preset determination level.

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

With this, the user does not need to perform a troublesome work such as operating the sensitivity setting volume and the like to set the detection condition, and the detection setting switch and the non-detection setting switch can be used by actually using the object to be detected. It can be set easily by operating the detection setting switch.

[0005]

[Problems to be solved by the device]

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

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

Therefore, for example, when the product flowing through the line is used as the detected object of the photoelectric switch, the detection output can be reliably obtained only when the detected object is present due to the determination level set as described above. It is necessary to test whether it can be obtained. If the test results show that the detection operation cannot be performed reliably, it is necessary to perform the setting work again. Even if the detection operation is started, it is impossible to completely eliminate the occurrence of erroneous detection because it is not known whether there is a sufficient margin for ambient light or noise.

The present invention has been made in view of the above circumstances, and an object thereof is to be able to set a determination level of the presence or absence of an object by a simple operation, and to set the determination level by disturbance light. Another object of the present invention is to provide a detection switch device capable of confirming whether or not erroneous detection due to noise or hysteresis characteristics of a comparator can be prevented.

[0009]

[Means for Solving the Problems]

 The present invention is directed to a detection switch device that determines the presence or absence of an object to be detected by comparing the level of a detection signal output from a detection unit with a determination level and outputs an object detection signal. A first setting switch operated in the presence of the detected object; a second setting switch operated in the absence of the detected object; and a second setting switch operated when the first setting switch is operated. The level of the detection signal supplied from the detection unit is set as the first detection level, and the level of the detection signal supplied from the detection unit when the second setting switch is operated is stored as the second detection level. Judgment level setting means for setting the judgment level based on the first and second detection level values, and a judgment margin in which the difference between the first and second detection level values is stored in advance. Having features and alarm output means for outputting an alarm signal when less than the value at which is constructed set only.

[0010]

[Action]

 According to the detection switch of the present invention, when the first setting switch is operated in the presence of the detected object and the second setting switch is operated in the absence of the detected object, the judgment level setting means is , The level of the detection signal obtained in each state is stored, and the determination level is set based on those levels. Then, the alarm output means determines whether or not the difference between the stored first detection level and the stored second detection level is smaller than a preset determination margin value. An alarm signal is output indicating that the detection operation cannot be performed reliably, and if the alarm signal is not output, the detected object can be reliably detected by the set judgment level. It becomes unnecessary to confirm the detection operation by using.

[0011]

【Example】

 Hereinafter, a first embodiment in which the present invention is applied to a reflective photoelectric switch will be described with reference to FIGS. 1 to 4.

In FIG. 1 showing the overall electrical configuration, a microcomputer 1 is a so-called one-chip microcomputer in which a CPU, a ROM, a RAM, an A / D conversion circuit and the like are built in, and a decision level setting means. It also has a function as an alarm output means, and an object detection and detection sensitivity setting program described later is stored in advance.

The anode of the light emitting diode 2 is connected to the DC power supply terminal 4 via the resistor 3, and the cathode is grounded via the transistor 5. The base of the transistor 5 is connected to the output terminal A of the microcomputer 1. The cathode of the photodiode 6 is connected to the DC power supply terminal 4, and the anode is connected to the analog input terminal B of the microcomputer 1 through the amplifier 7 and the input / output terminals P and S of the light receiving gain variable circuit 8. The selection input terminal of the light receiving gain variable circuit 8 is connected to the output terminal C of the microcomputer 1.

The detection setting switch 9 as the first setting switch and the non-detection setting switch 10 as the second setting switch are respectively connected between the input terminals D and E of the microcomputer 1 and the ground. .. The anode of the output display light emitting diode (hereinafter referred to as LED) 11 is connected to the output terminal F of the microcomputer 1, and the cathode is grounded via the resistor 12. The anode of the LED 13 for alarm display is connected to the output terminal G of the microcomputer 1, and the cathode is grounded via the resistor 14.

The data input / output terminal of the EEPROM (rewritable nonvolatile memory) 15 is connected to the data input / output terminal H of the microcomputer 1. The microcomputer 1 is adapted to read or write necessary data, which will be described later, from the EEPROM 15 at any time.

The base of the npn-type transistor 16 for object detection output is connected to the output terminal I of the microcomputer 1 via the resistor 17, the collector is connected to the output terminal 18, the emitter is grounded and the GND terminal 19 is connected. It is connected to the. The base of the npn transistor 20 for abnormal alarm output is connected to the output terminal J of the microcomputer 1 via the resistor 21, the collector is connected to the alarm output terminal 22 and the emitter is connected to the GND terminal 19.

Next, as shown in FIG. 2, the above-described light-receiving gain variable circuit 8 is connected to the amplifier 24 via the first-stage multiplexer 23, and its output terminal is connected to the second-stage multiplexer 25. The output terminal of the amplifier 26 is connected to the input terminal B of the microcomputer 1.

Each of the multiplexers 23 and 25 has, for example, n input terminals, and adjacent input terminals are connected by a predetermined voltage dividing resistor r, and the input terminal Xn of the first-stage multiplexer 23 is connected. Is connected to the input terminal P and the output terminal X is connected to the non-inverting input terminal of the amplifier 24. The input terminal X n of the second stage multiplexer 25 is connected to the output terminal of the amplifier 24, and the output terminal X is connected to the output terminal S.

The multiplexers 23 and 25 are adapted to be supplied with a selection signal from the output terminal C of the microcomputer 1 at their selection input terminals, and output one of the input terminals Xn to X1 according to the selection signal. The multiplexer 23 is brought into conduction with the terminal X, whereby the multiplexer 23 supplies the detection signal input from the input terminal P to the amplifier 24 with 0 to n−1 resistances r, and the multiplexer 24. Similarly, 25 also puts the output signal of the amplifier 24 at the output terminal S by setting the resistance r through 0 to n-1. Therefore, the first-stage and second-stage multiplexers 23 and 25 can output the detection signal from the input terminal P to the output terminal S after adjusting n × n stages.

Next, the operation of this embodiment will be described with reference to FIGS. 3 and 4. In the present embodiment, the case where the number of selection stages of the multiplexers 23 and 25 is 32 (n = 32) will be described. As the operation of the microcomputer 1, the detection operation (1) performed according to the detection program shown in the flowchart of FIG. 3 will be briefly described, and subsequently, the detection setting switch 9 or the non-detection setting switch 10 is operated. The (2) sensitivity adjustment operation at this time will be described in detail.

(1) Detection Operation First, when the power is turned on, the microcomputer 1 starts the detection program, and when the initialization operation is executed in step S1, the detection time setting switch 9 is executed in the following steps S2 and S3. Alternatively, it is determined whether or not the non-detection setting switch 10 is turned on. Now, since it is considered that neither of the switches 9 and 10 has been operated, the microcomputer 1 proceeds to the subsequent step S4.

At this time, the microcomputer 1 outputs a light emission signal from the output terminal A so as to turn on the LED 2 by an interrupt operation by another program not shown. Therefore, when there is reflected light from the object to be detected, the photodiode 6 detects the light reception signal. The light receiving signal from the photodiode 6 is given to the input terminal B of the microcomputer 1 as an analog signal via the amplifier 7 and the light receiving gain variable circuit 8.

The microcomputer 1 converts the analog signal supplied to the input terminal B into a digital detection signal L (A / D conversion), and in step S4, the value of the detection signal L is set to a preset comparison level. It is determined whether it is larger than R. Then, when the magnitude of the detection signal L is larger than the comparison reference level R, the microcomputer 1 determines "YES" and proceeds to step S5 to output the "H" level signal from the output terminal I. The object detection output transistor 16 is turned on, and in step S6, an "H" level signal is output from the output terminal F to energize and light the object detection display LED 11.

On the other hand, when the microcomputer 1 determines “NO” in step S 4, it leaves both the transistor 16 and the LED 11 in the off state (steps S 7, S 8). Then, when step S6 or S8 is completed, the microcomputer 1 returns to step S2 again and repeats the above detection operation.

(2)-(a) Sensitivity Adjustment Operation (Main Program) Next, the sensitivity adjustment operation when either the detection setting switch 9 or the non-detection setting switch 10 is turned on will be described. That is, when the detection setting switch 9 is turned on, the microcomputer 1 determines "YES" in step S2, moves to step S9, and executes the gain setting program.

This gain setting program will be described in detail later, but in short, the detection signal L obtained by A / D conversion in the microcomputer 1 with respect to the light reception signal given from the photodiode 6 is the comparison reference level R. This is a program for obtaining the light-receiving gain W in the light-receiving gain variable circuit 8 when the transistor 16 is turned on beyond the range.

Therefore, in this case, since the microcomputer 1 can obtain the light receiving gain V1 in the state where the object to be detected is present, in step S10, when the gain value W obtained by the gain setting program is detected. It is stored as the light receiving gain V1.

On the other hand, when the non-detection time setting switch 10 is turned on, the microcomputer 1 determines “YES” in step S3, moves to step S11, and executes the gain setting program in exactly the same manner as described above. carry out. In this case, since the non-detection setting switch 10 is turned on in the absence of the object to be detected, the microcomputer 1 sets the light receiving gain W obtained in the subsequent step S12 to the light receiving gain at the time of non-detection. It is stored as IN V2.

In this way, when the light receiving gains V1 and V2 at the time of detection and at the time of non-detection are obtained, the microcomputer 1 determines the average value of the values of these light receiving gains V1 and V2 in the following step S13. The gain is set as VS (= (V1 + V2) / 2). Next, in step S14, the microcomputer 1 sets the hysteresis value H for the value of the gain VS thus obtained.

The hysteresis value H is a value set to prevent chattering when the detection signal L and the comparison reference level R are compared in the microcomputer 1, and the hysteresis value H differs depending on the set gain VS. The (VS) data is pre-stored in the memory so that the optimum hysteresis value H can be set without making it unnecessarily large.

Now, in a succeeding step S15, the microcomputer 1 determines whether or not the gain difference ΔVS (= V1−V2) between the light receiving gains V1 and V2 is larger than the predetermined margin value M. In this case, the margin value M is stored in advance in the memory in accordance with the magnitude of the light receiving gain V1 as a value that does not cause false detection of the detected object due to ambient light or noise. When the setting gain VS is set to a large value because the level of the received light signal is low, the adverse effect of ambient light or noise may be large, so the value of the margin value M is also set to a large value. There is.

When it is determined in step S15 that the gain difference ΔVS is smaller than the margin value M and “NO”, the microcomputer 1 proceeds to step S16 to turn on the transistor 20 for alarm output. The signal of "H" level is output from J, and subsequently, the signal of "H" level is output from the output terminal G in step S17 to turn on the alarm display LED 13 by energizing.

In such a state, since the margin is small with the obtained set gain VS, a reliable detection operation cannot be guaranteed, and erroneous detection cannot be avoided. It can be seen that it is necessary to reset by changing the detection conditions.

On the other hand, when the value of the gain difference ΔVS is larger than the margin value M, the microcomputer 1 determines “YES” in step S15, moves to steps S18 and S19, and outputs the alarm output transistor 20 and The alarm display LED 13 is held in the off state.

In other words, this indicates that the set gain VS obtained in step S13 has a sufficient margin, so that the object can be reliably detected. Therefore, it is not necessary to perform a test using the test object after setting, and the actual detection operation can be directly performed.

(2)-(b) Sensitivity Adjustment Operation (Gain Setting Program) Next, details of the gain setting program will be described with reference to the flowchart of FIG. Here, a case where the detection time setting switch 9 is turned on and the gain value when the microcomputer 1 exhibits the detection state of the object by the received light signal is 21 will be described as an example.

When the program is started, the microcomputer 1 first substitutes a temporary value W0 for the value of the light reception gain W as a variable in step P1, and subsequently, in step P2, the maximum number of repetitions B0 ( For example, 5) is substituted. Subsequently, in step P3, the micro computer 1 substitutes the value 16 which is ½ of the maximum volume change width Vm (= 32) into the gain variable V, and in step P4 the gain change amount variable DV is gained. The value 8 which is 1/2 of the value of the variable V (= 16) is substituted, and in step P5, the counter C is adjusted the number of adjustments C0 (in this case, the multiplexers 23 and 25 can be adjusted in 32 steps). Therefore, the number of adjustments C0 is 6).

Next, the microcomputer 1 proceeds to Step P to temporarily prohibit the light projecting operation, and in this state, the gain setting value VS is set to the gain variable V (= 16) described above in Step P7. Along with setting the value, the hysteresis value H corresponding to the gain setting value VS is read from the hysteresis function H (V) in the memory and set in step P8. After that, the microcomputer 1 permits and starts the light projecting operation in step P9. This is for obtaining the light reception gain V when the detection output always shifts from the off side to the on side in the light reception detection operation.

Now, in this state, the microcomputer 1 receives the light receiving signal from the photodiode 6, and the gain-adjusted output by the light receiving gain VS that has been set is input. In step P10, the microcomputer 1 compares the detection signal L internally obtained by A / D conversion with the comparison reference level R, and if the detection signal L is large, determines "NO" and proceeds to step P11. If not, the process proceeds to step P12.

In step P11, the microcomputer 1 resets a value obtained by subtracting the value 8 of the gain change amount variable DV from the current value 16 of the gain variable V as the gain variable V (= 8). However, in this case, since it is assumed that the finally obtained gain value is 21, the microcomputer 1 determines to be "YES" in step P10, and therefore proceeds to step P12.

Then, in step P12, the microcomputer 1 substitutes the value 8 of the gain change amount variable DV into the gain change amount addition variable AV, and in the subsequent step P13, is the value of the substituted variable AV 0? It is determined whether or not it is determined to be "NO" in this case, and the process proceeds to step P14. In step P14, the microcomputer 1 adds the value 8 of the variable AV to the gain variable V (= 16) (V = V + AV) to set the value of the gain variable V to 24. When the value of the variable AV is 0 in step P13, the microcomputer 1 substitutes 1 for the value of the variable AV and proceeds to step P14.

Next, in step P16, the microcomputer 1 divides the value 8 of the gain change amount variable DV by 2 and substitutes it into the variable DV, and subtracts 1 from the value of the counter C to 5 (C ← C- 1) In the following step P18, it is determined whether or not the value of the counter C is 0. The microcomputer 1 determines "NO" in step P18 and returns to step P6.

Hereinafter, the microcomputer 1 repeats steps P 6 to P 17 until the value of the counter C becomes 0. At the time of this repetition, the value of the gain variation variable DV gradually changes from 8 to 4, 2, 1, 0, so that the gain value 21 to be finally obtained approaches after the end of 5 repetitions. Yuki is set in units of 1 level. In order to detect the gain value 32, the number of additions AV is set to 1 at the time of the sixth iteration even after the variable DV becomes 0 at the steps P13 and P15 after the fifth iteration. ..

In this case, since it is assumed that the gain value is 21, the light receiving signal L is compared in step P10 with the value of the gain variable V set to 24 in the second iteration, Since the value of the gain variable V is sometimes large, the gain change amount variable DV of 4 is subtracted at the third time, and the gain variable V becomes 20, and the gain variable V becomes 22 at the fourth time. Subsequently, at the fifth time, the gain variable V becomes 21 and matches the desired gain value 21.

When the six repetitions have been completed in this way, the value of the counter C is 0, so the microcomputer 1 determines “YES” in step P18, and proceeds to step P19. Here, it is determined whether the value of the light receiving gain W (= W0) is equal to the value of the gain variable V (= 21), and in this case, it is determined to be "NO". Then, in step P20, the microcomputer 1 substitutes the value 21 of the gain variable V into the light receiving gain W, then in step P21, the value of the repeat counter B is decremented by 1 to 4, and in step P22, "NO" , "And returns to step P3 again.

Hereinafter, the microcomputer 1 repeats steps P3 to P18 to set the value of the gain variable V again. At this time, when the value of the gain variable V becomes the same value 21 as the previous value, Then, in step P19, it is determined to be "YES" and this program is terminated. In other words, when the gain value is detected twice and exactly the same value is obtained, that value is regarded as a highly reliable gain value.

On the other hand, when it is determined to be “NO” in Step P19, that is, when the level of the received light signal is unstable and the gain value of the second time does not match the value of the first time, the gain of the second time is obtained. After substituting the value set in the variable V into the light receiving gain W (step P20), the repeat counter B is decremented by 1 again (step P21), and the process returns to step P3 to repeat the above process. This repetition is repeated up to 5 times, but if the previous light receiving gain W and the value of the gain variable V match midway, the program ends there, and if it does not match 5 times, Then, the program is terminated with the value of the gain variable V for the fifth time as it is as the light receiving gain W.

As described above, the light receiving gain W in the presence of the object to be detected is obtained, and the light receiving gain V1 at the time of detection is set in the main program. When the non-detection setting switch 10 is turned on, the above-described gain setting program is executed in exactly the same manner, and the light receiving gain W in the absence of an object is obtained. The light receiving gain V2 is set.

With this gain setting program, it is possible to retrieve the light receiving gain of 32 stages by the detection operation of 6 times, and by repeating the same detecting operation of the retrieved light receiving gain value up to 5 times, more accurate Value can be detected.

According to the present embodiment as described above, the user can easily set the light receiving gain by only operating the detection setting switch 9 and the non-detection setting switch 10. In the process of setting the light-receiving gain, when there is a gain difference, that is, a margin that is not erroneously detected due to hysteresis width, ambient light, noise, etc., it is set as it is, and when there is no margin, an alarm output is output and the transistor 20 is turned on. At the same time, since the alarm output display LED 13 can be turned on to notify the user, the user need not carry out a test of the detection operation using the object to be detected, and the detection operation can be performed reliably. You can get the status.

FIGS. 5 and 6 show a second embodiment of the present invention. The difference from the first embodiment is that the detection time setting switch 9 and the non-detection setting switch 10 are separated from the main body 27. It has just been configured.

That is, the input terminals D and E of the microcomputer 1 are connected to the input terminals 28 and 29, respectively, and the signal lines 18a, 5b corresponding to the five terminals 18, 19, 22, 28 and 29, respectively. 19a, 22a, 28a, and 29a are connected, and a power supply line 4a is connected to the DC power supply terminal 4 to form an input / output cable 30 for the main body 27.

With this configuration, the detection-time setting switch 9 and the non-detection-time setting switch 10 can be used by connecting them to the signal lines 28a and 29a of the input / output cable 30, for example, the main body 27. Even if it is difficult for the user to operate the setting switch 9 for detection and the setting switch 10 for non-detection at the place where the is installed, it is possible to easily operate from a distant position, and to obtain a better operability. You can

In each of the above embodiments, the determination level is set by changing the level of the light receiving signal by setting the light receiving gain V by using the light receiving gain variable circuit 8. However, the setting is not limited to this. Instead, for example, the judgment level may be changed and set substantially by changing the projection amount, or the comparison reference level itself may be changed in the microcomputer 1 to set the judgment level. But it's good.

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

Furthermore, in the above-described embodiment, the detection-time setting switch 9 and the non-detection-time setting switch 10 are provided separately, but the present invention is not limited to this, and a configuration having a similar function with one switch is also possible. Is also good. That is, for example, the detection program stored in the microcomputer is configured to function as a detection time setting switch when the switch is first operated and as a non-detection time setting switch when the switch is operated next. Is also good.

[0057]

As described above, according to the detection switch device of the present invention, by providing the alarm output means, the difference between the first and second detection levels is smaller than the preset judgment margin value. Since the alarm signal is output at the time of opening, whether or not the presence or absence of the detected object can be reliably detected at the set determination level can be determined without actually using the detected object. This eliminates the need for troublesome setting work and improves the usability for the operator.

[Brief description of drawings]

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

FIG. 2 is an electrical configuration diagram showing a portion of a light receiving gain variable circuit.

FIG. 3 is a flowchart of a detection program.

FIG. 4 is a flowchart of a gain setting program.

FIG. 5 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 6 is a side view showing an input / output cable portion.

[Explanation of symbols]

1 is a microcomputer (determination level setting means, alarm output means), 2 is a light emitting diode, 4 is a DC power supply terminal,
6 is a photodiode, 8 is a light receiving gain variable circuit, 9 is a detection setting switch (first setting switch), 10 is a non-detection setting switch (second setting switch), 11 is an output display LED, and 13 is An alarm output display LED, 15 is an EEPROM, 16 is a detection output transistor, 20 is an alarm output transistor, 23 and 25 are multiplexers, 27 is a main body, and 30 is an input / output cable.

Claims (1)

[Scope of utility model registration request] 1. A detection switch device for determining the presence or absence of an object to be detected by comparing the level of a detection signal output from a detection section with a determination level and outputting an object detection signal, wherein the object to be detected is present. A first setting switch operated in a state of being operated, a second setting switch operated in a state in which the object to be detected does not exist, and provided from the detection unit when the first setting switch is operated. The level of the detection signal is set as a first detection level, and the level of the detection signal given from the detection unit when the second setting switch is operated is stored as a second detection level and the first and second detection levels are stored. The judgment level setting means for setting the judgment level based on the detection level value, and the difference between the first and second detection level values being smaller than a preset judgment margin value. And a warning output means for outputting a warning signal when the detection switch device is used.