JPH0795101B2 - Function photoelectric switch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photoelectric switch, and in particular, it arbitrarily ignores slight light blocking during light entering, or ignores slight light entering during light blocking. The present invention relates to a functional photoelectric switch having a function.

(Prior Art) A conventional photoelectric switch mainly includes a light emitter, a light receiver for receiving the light emitted from the light emitter, and a comparator for comparing the output of the light receiver with a reference voltage.

In such a photoelectric switch, a noise pulse may be included in the output signal of the comparator due to the influence of noise such as ambient light. Such a noise pulse may cause a malfunction in an electric device to which the photoelectric switch is connected, so it is necessary to remove it.

In addition, even if it is not a noise component, there is a case where it is desired to ignore a slight light blocking during light entering, or to ignore a slight light entering during light blocking. For example, when a certain component is aligned and supplied to the transport path by a so-called parts feeder, a photoelectric switch is provided at an appropriate position of the transport path to detect the presence or absence of the component in the transport path. Then, when there are more than a certain number of parts in the transport path, the parts feeder is stopped to prevent wear of the parts, while when there are less than a certain number of parts in the transport path, the parts feeder is operated continuously. Supplies parts to the transport path.

In the latter case, an output signal having a short pulse width is output from the photoelectric switch when a component being supplied to the transport path crosses a photoelectric switch provided on the way of the transport path. However, in this case, since the parts are being supplied, it is not desirable to stop the parts feeder depending on the output signal. Even in such a case, when the parts feeder stops, the parts feeder stops and starts every time the parts pass through the transport path, so that not only the parts are not smoothly supplied, but also the parts feeder is stopped. Noise accompanying stop and start may cause malfunction of other electric devices, which is inconvenient.

Therefore, in order to ignore the noise component included in the output signal of the comparator of the photoelectric switch, the slight light blocking during the light reception, or the slight light input during the light blocking, the following means is provided. Has been taken.

Firstly, there is a means for installing a filter for removing noise in a hardware manner on the side of an electric device to which such a photoelectric switch is connected.

Secondly, there is a means for removing noise or the like contained in the output signal by software when the output signal of the photoelectric switch is taken into the microcomputer which is the control unit of the electric device.

(Problems to be Solved by the Invention) However, according to the first means, since the constant of the filter is fixed, for example, when changing the light-shielding time width to be ignored during light reception, etc. Each time,
There is the annoyance of having to recreate the filter.

Further, according to the second means, the inconvenience of the first means is avoided, but the microcomputer of the electric device to which the photoelectric switch is connected is used for processing the output signal of the photoelectric switch. While occupied, the original signal processing of the electric device cannot be performed, which may cause inconvenience in control of the electric device.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a functional photoelectric switch capable of easily changing the setting of the time width of light reception or light shielding to be ignored.

Another object of the present invention is to provide a functional photoelectric switch that does not occupy the control unit of the electric device to which the photoelectric switch is connected in processing the output signal of the photoelectric switch.

(Means for Solving the Problems) The present invention has the following features in order to achieve the above object.

That is, the functional photoelectric switch according to the present invention comprises a light projecting means,
A light receiving means for receiving and detecting the light emitted from the light emitting means, a comparing means for comparing the output signal of the light receiving means with a reference voltage, and a processing procedure of the output signal of the comparing means are arbitrarily selected and set. The function selecting means, the control means for processing and outputting the output signal from the comparing means by the processing procedure set by the function selecting means, and the one-shot pulse width or the delay time of the output signal of the controlling means are arbitrary. And a timer setting means for setting.

(Embodiment) FIG. 1 is a schematic view of the appearance of a functional photoelectric switch according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the outline of the configuration of the functional photoelectric switch shown in FIG.

In FIG. 1, reference numeral 1 indicates a switch body. The switch body 1 includes an electric circuit having the configuration shown in FIG. That is, the switch body 1 includes a light emitting diode 11 as a light projecting means, and a photodiode 12 as a light receiving means for detecting the light emitted from the light emitting diode 11.

The light emitting diode 11 is driven by a light projecting circuit 13. The output of the photodiode 12 is given as one input of the amplification / comparison circuit 14. As the other input of the amplification comparison circuit 14, the variable resistor 1 connected to the reference voltage source Vref
A reference voltage divided by 5 is given.

The output signal of the amplification comparison circuit 14 is given to the microcomputer 16 as a control means for processing the output signal. A function selection switch SW1 and a timer set switch SW2 are provided in association with the microcomputer 16.

The function selection switch SW1 corresponds to a function selection means for instructing the microcomputer 16 to process the output signal of the amplification comparison circuit 14. In addition, timer set switch SW2
Corresponds to timer setting means for arbitrarily setting the one-shot pulse width or the delay time of the output signal of the microcomputer 16 and instructing the microcomputer 16 in relation to the output signal of the amplification comparison circuit 14.

On the other hand, one end of an optical fiber 2 is attached to the switch body 1. One end of the optical fiber is optically coupled to the light emitting diode 11 and the photodiode 12. The light emitted from the light emitting diode 11 is transmitted through the optical fiber 2 and is emitted from the other end of the optical fiber 2. The other end of the optical fiber 2 is appropriately installed in relation to the detected object. The light emitted from the optical fiber 2 is reflected by the object to be detected, and the reflected light is transmitted through the optical fiber 2 and is incident on the photodiode 12.

Reference numeral 3 shown in FIG. 1 is a resistance value adjusting screw of the variable resistor 15, which is used for setting the reference voltage applied to the amplification comparison circuit 14. Reference numeral 4 shown in the figure denotes a cable for transmitting the output signal of the microcomputer 16 to an electric device (not shown).

Next, the operation of the functional photoelectric switch having the above configuration will be described.

3 to 9 are flowcharts showing the operation procedure of the microcomputer 16, and FIGS. 10 to 17 show output waveform charts of the amplification comparison circuit 14 and output waveform charts of the microcomputer 16 in each function. There is.

First, by setting the function selection switch SW1, the microcomputer 16 is instructed to process the output signal of the comparison and amplification circuit 14. The function selection switch SW1 is composed of a 4-bit digital switch and is capable of instructing 16 kinds of processing procedures. In this embodiment, 8
Instructing the kind of processing procedure.

Further, the timer set time is appropriately set in the timer set switch SW2. Timer set switch SW2 is 4
It is composed of a bit digital switch, and indicates the digit (for example, msec, 10 msec, 100 msec, 1 sec) of the timer set time by the combination of the switches of the last two digits. In addition, a numerical value (for example, 1, 2, 3, 4) of the timer set time is instructed by the combination of the upper two digit switches.

Hereinafter, the signal processing procedure of the microcomputer 16 after the instruction by these switches is performed will be described.

As shown in FIG. 3, the microcomputer 16 reads the state of the function selection switch SW1.

If the function selection switch SW1 is set to "0000",
It means an instruction of a procedure for outputting the output signal of the amplification comparison circuit 14 as it is. Therefore, the microcomputer 16 processes the output signal in accordance with the procedure stored in advance as shown in FIG. That is, it is determined whether or not light is incident, and "H" is output if light is incident, and "L" is output if light is not incident. And the function selection switch
Read the status of SW1 and repeat the same signal processing procedure. As a result, the comparison and amplification circuit as shown in FIG.
The 14 output signals (hereinafter referred to as comparison output signals) are directly output as the output signals of the microcomputer 16 (hereinafter referred to as processing output signals) as shown in FIG. 10 (b).

If the function selection switch SW1 is set to "0001",
It means an instruction of a processing procedure for inverting and outputting the comparison output signal. Therefore, as shown in FIG. 5, the microcomputer 16 determines whether or not there is light incident, outputs “L” if light is incident, and outputs “H” if light is not incident. . As a result, an inverted processed output signal as shown in FIG. 11 (b) is output with respect to the comparison output signal as shown in FIG. 11 (a).

If the function selection switch SW1 is "0010",
It means the instruction of the procedure to give a one-shot “H” output when there is light incident. Therefore, the microcomputer 16
Determines whether or not light is incident, as shown in FIG. When light is received, read the instruction of the timer set switch SW2 and set the timer. Then, "H" is output and this state is maintained until the timer expires.
When the timer expires, "L" is output. The "L" state is maintained as long as the light continues to enter. On the other hand, when there is no light incident, the state of the function selection switch SW1 is read again. As a result, the comparison output signal shown in FIG. 12 (a) is output as the processed output signal as shown in FIG. 12 (b). As is clear from FIG. 12, the pulse waveform appearing within the timer set time from the rising of the comparison output signal is ignored.

If the function selection switch SW1 is set to "0011",
It means the instruction of the procedure to give a one-shot “H” output when shielded from light. Therefore, the microcomputer 16
Determines whether or not light is incident, as shown in FIG. When the light is blocked, read the instruction of the timer set switch SW2 and set the timer. Then, "H" is output and this state is maintained until the timer expires.
When the timer expires, "L" is output. The "L" state is maintained as long as the light is blocked. On the other hand, when light is incident, the state of the function selection switch SW1 is read again. As a result, the comparison output signal shown in FIG. 13 (a) is output as the processed output signal as shown in FIG. 13 (b). As is clear from FIG. 13, the Hals waveform appearing within the timer set time from the fall of the comparison output signal is ignored.

On the other hand, when the function selection switch SW1 is set to "0100", it means the instruction of the procedure to give the one-shot "L" output when the light is incident. The processing procedure of the microcomputer 16 based on this instruction is almost the same as that in FIG. However, "L" is output at the step in the figure and "H" is output at the step. The comparison output signal at this time is shown in FIG. 14 (a), and the processed output signal is shown in FIG. 14 (b).

Further, when the function selection switch SW1 is "0101", it means the instruction of the procedure to give the one-shot "L" output when the light is shielded. The processing procedure of the microcomputer 16 based on this instruction is shown almost in the same manner as in FIG. However, "L" is output at step and "H" is output at step. The comparison output signal at this time is shown in FIG. 15 (a), and the processed output signal is shown in FIG. 15 (b).

If the function selection switch SW1 is "0110",
It means the instruction of the procedure to ignore the momentary incoming light. Therefore,
As shown in FIG. 8, the microcomputer 16 first determines whether or not there is light incident. When light enters,
Read the instruction from the timer switch SW2 and set the timer. The timer set time at this time is appropriately determined in advance in relation to the light-shielding time to be ignored. Then, it is determined whether or not the timer set time has expired. When the timer set time ends, "H" is output. The "H" state is maintained while light is entering, and "L" is output when the light is blocked. As a result, the momentary incident light in the comparison output signal as shown in FIG. 16 (a) is ignored, and the processed output signal as shown in FIG. 16 (b) is output.

If the function selection switch SW1 is "0111",
It means the instruction of the procedure to ignore the momentary shading. Therefore,
As shown in FIG. 9, the microcomputer 17 determines whether or not light is incident, and outputs "H" when light is incident. Next, the timer set time is read, and it is judged again whether or not there is light incident. The time during which the light is incident returns to the step, and the "H" state is maintained. When the light is shielded, it is determined whether or not the timer set time has expired. If the timer set time has not expired, return to step. When the timer set time ends, "L" is output. As a result, the momentary shading in the comparison output signal shown in FIG. 17 (a) is ignored, and the processed output signal as shown in FIG. 17 (b) is output.

In the description of the embodiments, the processing of eight types of comparison output signals has been described, but the present invention is not limited to this. For example, in FIGS. 8 and 9, the case where "H" is output by the incident light has been described as an example, but this may give a reverse output. The procedure shown in FIG. 8 is a so-called on-delay function, and the procedure shown in FIG. 9 is a so-called off-delay function. The comparison output signal is processed by combining both such on-off delays. It is also possible.

(Effect) As is apparent from the above description, the functional photoelectric switch according to the present invention includes the processing of the output signal of the comparing unit in the functional photoelectric switch according to the procedure instructed by the function selecting unit and the timer setting unit. The control unit is doing this. Therefore, according to the present invention, when changing the time width of light input or light blocking to be ignored, the change setting of the processing procedure of the output signal of the comparing means corresponding to this is set by the function selecting means and the timer setting means. Since it can be easily done by changing the instruction, it is much more convenient compared to the conventional method where the filter circuit was recreated, and it is also easy to change the detected object such as setting the light shielding time width and changing the processing procedure. Can now correspond to.

Furthermore, since the functional photoelectric switch according to the present invention includes the control unit that processes the output signal of the comparison unit according to the instructed procedure, in processing the output signal, the electrical device to which the photoelectric switch is connected is processed. Does not occupy the control unit. Therefore, according to the present invention, the utilization efficiency of the control unit of the electric device to which the photoelectric switch is connected is improved, which is convenient for performing the original control of the electric device.

[Brief description of drawings]

FIG. 1 is an external view of a functional photoelectric switch according to an embodiment, FIG.
FIG. 10 is a block diagram showing the configuration of the functional photoelectric switch shown in FIG. 1, FIGS. 3 to 9 are flowcharts showing the processing procedure of the comparative output signal of the photoelectric switch according to the embodiment, and FIG.
FIG. 17 to FIG. 17 are operation waveform diagrams of the comparison output signal and the processed output signal in each signal processing. 11 …… Light emitting diode, 12 …… Photodiode, 13 ……
Emitter circuit, 14 …… Comparison amplifier circuit, 15 …… Variable resistor, 16
…… Microcomputer. SW1 …… Function selection switch, SW2 …… Timer set switch.

Claims (1)

[Claims] 1. A light projecting means, a light receiving means for receiving and detecting light emitted from the light projecting means, a comparing means for comparing an output signal of the light receiving means with a reference voltage, and an output signal of the comparing means. A function selecting means for arbitrarily selecting and setting a processing procedure, a control means for processing and outputting an output signal from the comparing means by the processing procedure set by the function selecting means, and an output signal of the control means. A functional photoelectric switch comprising a timer setting means for arbitrarily setting a one-shot pulse width or a delay time.