TWI400471B - Optoelectronic sensor and optoelectronic sensor system - Google Patents

Description

Photoelectric detector and photo-sensing system

The present invention relates to an optical sensor and a photo-sensing system for detecting the presence or absence of a subject based on a difference in the level of a light-receiving signal when a light-emitting element and a light-receiving element are present.

In the photodetector and photo-sensing system for detecting the presence or absence of the object to be detected based on the difference between the light-receiving signal level when the object to be detected exists between the light-emitting element and the light-receiving element, the pair of light-emitting elements The light receiving element is generally disposed such that the light path from the light projecting element to the light receiving element is parallel to the axis of the object to be detected. However, when the thickness of the subject is thin, for example, when the subject is a thin flat plate, the optical path parallel to the axis of the subject is not blocked by the subject, and thus the subject may not be detected. In JP-A-H08-148981 (Patent Document 1), a detection method has been proposed which is disposed in a multi-optical-axis photodetector in which a plurality of light projecting portions and a light receiving portion are opposed to each other. The light-receiving portion of the segment different from the light projecting portion that emits the light-emitting signal is detected.

According to this method, since the light path from the light projecting portion to the light receiving portion has an angle with respect to the horizontal direction, that is, the tilt, even if the thin flat object is disposed such that its axis is horizontal, the light path is detected. This detection can be achieved by body shading.

[Patent Document 1] Japanese Patent Publication No. 8-148981

However, in the case where the object to be detected is extremely thin, there is a case where it cannot be detected by the method disclosed in Patent Document 1. Further, even when the subject is shielded from the light path, if the subject is translucent, the change in the light receiving level of the light receiving unit is small, and the detection is affected by the disturbance of illumination or reflection around the light receiving unit. The result becomes an incorrect question.

Therefore, an object of the present invention is to provide a photodetector and a photo-sensing system that can accurately detect a subject without being disturbed even when the subject is extremely thin.

In the first aspect of the photodetector of the present invention, the light projecting portion and the light receiving portion are provided to face each other, and the intensity of the light receiving signal of the light receiving portion is detected to be detected between the light projecting portion and the light receiving portion. The presence or absence of the object to be detected in the space, and the light receiving unit has the first light receiving element and the second light receiving element that operate in synchronization with the light emission timing signal of the light projecting unit. Further, the light projecting unit includes a first light projecting element, and the light projecting signal is arranged such that the light projecting signal reaches the first light receiving element without intersecting with the object to be detected, and reaches the first light receiving element when intersecting with the object to be detected. The second light-receiving element and the second light-emitting element are arranged such that the light-emitting signal reaches the second light-receiving element without crossing the object, and reaches the first light-receiving device when intersecting with the object. element. Then, a pair of the first light projecting element and the first light receiving element, and a pair of the first light projecting element and the second light receiving element are referred to as a first group, and the second light projecting element and the pair A pair of the first light-receiving elements and a pair of the second light-emitting elements and the second light-receiving element are set to the second group, and in the first group, the first group is not attenuated by the object. The positional difference between the light receiving signal of the light receiving element and the light receiving signal of the second light receiving element that is attenuated by the object to detect the presence or absence of the object. Further, in the second group, the light receiving signal of the first light receiving element attenuated by the object and the level difference of the light receiving signal of the second light receiving element which is not attenuated by the object are compared. In order to detect the presence or absence of the subject, the information on the presence or absence of the subject obtained from the first group and the presence or absence of the subject obtained from the second group are detected in a double comparison.

In this case, the comparison of the level differences in the first group may be performed at the light emission timing of the first light projecting element, and the light emission timing of the second light projecting element may be performed in the second group. Comparison of this bit difference. Further, in this photodetector, the light-receiving signals from one of the light-emitting elements are received by the two light-receiving elements, and this type is sometimes referred to as a first photo-electrical sensor in the following description.

In the second aspect of the photodetector of the present invention, the light projecting portion and the light receiving portion are provided to face each other, and the intensity of the light receiving signal of the light receiving portion is detected to be detected between the light projecting portion and the light receiving portion. The presence or absence of the object to be detected in the space, and the light projecting portion is projected on the first light projecting element that has reached the light projecting signal of the light receiving unit without intersecting the object to be detected; and is projected to intersect the object to be detected. In the case of the second light projecting element that reaches the light projecting signal of the light receiving unit. Then, the time-division light-receiving signal generated by receiving the light-emission signal that is not attenuated by the object from the first light-emitting element is compared, and the object from the second light-emitting element is received by the object. The level difference of the other time-division received light signal generated by the attenuated light projecting signal to detect the presence or absence of the detected object. In this case, the light-emitting elements receive the light-emitting signals from the two different light-emitting elements. In the following description, this type may be referred to as a second photo-electric detector. Further, although two light-receiving signals are generated from one light-receiving element, the light-receiving signal is divided into a light-receiving time from one of the light-emitting elements and a light-receiving time from the other light-emitting element, that is, time-division light is received, and The light receiving time of the former is a time-sharing light signal, and the light receiving time of the latter is another time-sharing light signal. A third aspect of the photodetector of the present invention has a light projecting portion and a light receiving portion that are disposed opposite to each other, and is detected between the light projecting portion and the light receiving portion by a change in intensity of a light receiving signal of the light receiving portion. The presence or absence of the object to be detected in the space includes the first light projecting element and the second light projecting element. Further, the light receiving unit has a light projecting signal that receives the light from the first light projecting element that is not attenuated by the object, and a light projecting signal that is attenuated by the object from the second light projecting element. a first light receiving element; and a light projecting signal from the second light projecting element that is not attenuated by the object and a light projecting signal that is attenuated by the object from the first light projecting element; The second light receiving element. Further, a pair of the first light projecting element and the first light receiving element, and a pair of the second light projecting element and the first light receiving element are referred to as a first group, and the second light projecting element and the pair A pair of the second light-receiving elements and a pair of the first light-emitting elements and the second light-receiving elements are set to the second group, and the first group is not attenuated by the first object. The time-division light-receiving signal of the light-receiving element and the level difference of the other time-division light-receiving signal of the first light-receiving element that is attenuated by the object to be detected are detected to detect the presence or absence of the object. Further, in the second group, the time-division light-receiving signal of the second light-receiving element attenuated by the object and the other time-sharing of the second light-receiving element that is not attenuated by the object are compared. The position difference of the received light signal is used to detect the presence or absence of the object, and the presence or absence of the object obtained from the first group and the object obtained from the second group are detected in a double comparison. Whether or not there is information.

In this case, the comparison of the level differences may be performed at the time division projection timing of the first light projecting element and the second light projecting element.

In addition, since the photodetector also receives the light projecting signal from one of the light projecting elements by the two light receiving elements, the following description is the same as the second type of the present invention, sometimes referred to as the second photo inductor. Detector.

Further, when the light projecting unit has the first and second light projecting elements and has the first and second groups, the presence or absence of the object and the second information obtained in the first group may be The presence/absence information of the subject obtained by the group is double compared to the presence or absence of the subject, and the abnormal state and/or the sensing of the subject is detected without detecting the presence or absence of the subject. The device is faulty.

Further, the photodetector may be configured in a plurality of stages, and a photodetector for detecting a plurality of the objects to be detected may be formed, or may be shared by the second group of light projecting elements of the second group and used for The second light-emitting elements of the first group are shared by the second light-receiving elements of the second group and the other light-receiving elements of the first group adjacent to the detected object in the second group and used for the The other object to be detected is the first light receiving element of the first group. Alternatively, the second light projecting element may share the first light projecting element as another object to be detected adjacent to the object to which the light is projected, and the second light receiving element may be shared. The first light receiving element of the other object to be detected.

Furthermore, in either case, the pair of light projecting sections and the light receiving sections may be unitized.

The photo-sensing system of the present invention includes any one of the plurality of photo-sensing devices described above, and includes a first management sub-station connected to the series of the light-emitting portions and a series of ones corresponding to the light-emitting portions The second management substation to which the light receiving unit is connected. Further, the first management substation generates the light emission timing signal, and the second management substation generates a timing signal of the light receiving signal synchronized with the light emission timing signal.

Moreover, the photo-sensing system of the present invention may be configured such that a plurality of the light projecting portions and a series of the light-receiving portions are connected to a common data signal line, and the presence or absence of information of the object to be detected is transmitted to the parent station. Detection of abnormal state of the body and / or sensor failure information.

Further, the photo-sensing system of the present invention may be provided in the first group and the second group of light-emitting elements having the first and second light-emitting elements, and the first and second groups of optical-inductance sensors may be provided in the first group. The presence or absence of the obtained information of the subject and the presence or absence of the subject obtained in the second group are compared with the presence or absence of the subject, and the presence or absence of the subject is not detected. An abnormal state of the object to be detected and/or a sensor failure.

The photodetector of the present invention causes the light receiving portion to function as a reference sensor and a detecting sensor, that is, a sensor (reference sensor) that functions to receive a light projecting signal that is not blocked by the object to be detected, and is received by A sensor (detection sensor) that emits a light signal that is blocked by the object when the object is positioned between the light projecting portion and the light receiving portion, and detects by comparing the reference sensor and the detecting sensor The presence or absence of the detected object. At this time, since the light receiving unit that is the detecting sensor receives the light projecting signal that reaches the light receiving unit when the light projecting portion intersects with the object to be detected, the light receiving signal is attenuated when the object is present. Further, by comparing the two detection results, that is, by obtaining the difference between the two received light signals, the influence of the disturbance can be eliminated. Therefore, even when the object to be detected is extremely thin, it is not affected by the disturbance, and the object to be detected can be accurately detected.

Moreover, the comparison between the received light signal that is received by the light receiving unit and is not attenuated by the object and the level difference of the light receiving signal that is attenuated by the object is performed at the end of the light receiving end of the received light signals, that is, When the photodetector is in the light projecting timing of the light projecting portion, and the second photodetector is in the light projecting timing of the second light projecting element, the presence or absence of the object to be detected is detected in each segment. Therefore, the response time to the detected object is short, and a high-speed response speed can be obtained.

Further, in the light projecting unit, the first and second light projecting elements are used, and the light receiving unit includes the first and second light receiving elements, and the pair of the first light projecting element and the first light receiving element, and the first light projecting unit. A pair of the element and the second light receiving element is the first group, and a pair of the second light projecting element and the first light receiving element and a pair of the second light projecting element and the second light receiving element are set to the second group. By double the detection structure, the detection accuracy of the subject can be made higher. Further, in this case, in the first photodetector, the collimation timing of the first light projecting element is compared with the level difference of the first group, and the light projection timing of the second light projecting element is performed for the second time. In the comparison of the positional difference of the group, in the second photodetector, the light projection timing of the second light projecting element is performed, whereby the presence or absence of the object to be detected is detected in each segment. Therefore, the response time to the detected object is short, and a high-speed response speed can be obtained. Further, by comparing the presence or absence of the object to be detected, if the presence or absence of the object is not detected, the abnormal value of the object can be detected based on the logical value obtained by logically determining the plurality of received light signals. Or storage status (inclined placement), or sensor failure.

Further, the light projecting unit has the first and second light projecting elements, and the light projecting element and the light receiving element have the first and second groups. When the scattered light from the light projecting element is used, the light is shared by the second group. The second light projecting element and the first light projecting element in the first group of the other object to be detected adjacent to the object to be detected in the second group have halved the light projecting element. Simpler construction.

Further, when the pair of light projecting portions and the light receiving portion are unitized, since the interval between the respective segments can be freely set, the object to be detected can be applied to various thicknesses or sizes, and the object to be detected can be greatly enlarged. The range of applications where the shapes are different.

In the photo-sensing system of the present invention, since the photodetector of the present invention is provided, even when the object to be detected is extremely thin, it is not affected by the disturbance, and the object to be detected can be accurately detected. Moreover, the response time of the presence or absence of the subject is increased, and the detection structure is doubled, thereby obtaining an improvement that the presence or absence of the subject can be reliably detected. Further, based on the logical value obtained by logically determining the plurality of received light signals, the abnormality holding or storage state (oblique placement) of the object or the sensor failure can be detected, and reliability can be improved. Further, since the interval between the segments can be freely set, it is possible to greatly expand the range of application to the case where the thickness or the size of the object to be detected differs from the shape of the object to be detected.

In addition, since the optical inductance detector can be used to detect the abnormality of the object to be detected or stored (oblique) or the logic of the sensor failure, the judgment of the photo-sensing system can also be utilized. The device (PLC or main computer, etc.) is performed.

Hereinafter, an embodiment of a first photodetector and a photo-sensing system including the photo-electrical sensor of the present invention will be described with reference to the drawings.

1 is an overall view of an embodiment of a photo-sensing system of the present invention, and FIG. 2 is a block diagram of the photo-sensing system. The photo-sensing system connects a plurality of photo-inductors 11 to a DP signal line 7 and a DN signal line 8 which are shared data signal lines. The photodetector 11 is composed of a management substation 10a, 10b, a plurality of substation input units 12b connected in series from the management substation 10b, and a plurality of substation output units 12a connected in series from the management substation 10a. The substation input unit 12b corresponds to the light projecting unit of the present invention, and the substation output unit 12a corresponds to the light receiving unit of the present invention for detecting the presence or absence of being detected between the substation output unit 12a and the substation input unit 12b. body. For example, in a system in which the position of the scaffold in which the object to be detected is located in the scaffolding structure is grasped, the position or condition of the scaffold in which the semiconductor wafer, the liquid crystal panel, or the like is stored is grasped. However, the object to be detected is not limited to this, and may be an object that is not shaped or has a different shape.

The management substation 10a, 10b, the substation input unit 12b, and the substation output unit 12a constituting the photodetector 11 share the parent station 6 and the data, and the parent station 6 transmits and receives data to and from the control unit 1 in parallel signals. That is, the control unit output signal 4 which is a parallel (parallel) output signal is sent from the output unit 2 of the control unit 1 to the parent station 6, and the input unit 3 receives the parallel input signal from the parent station 6 as the control unit input signal 5, and is received. The communication between the control unit 1 of the main system and the parent station 6 is to transmit and receive parallel signals and perform signal transmission at high speed. The mother station 6 is connected to the DP signal line 7, the DN signal line 8, and is connected to the photodetector 11 to which the signal line is connected. Further, the substation input unit 12b and the substation output unit 12a constituting the photodetector 11 are also connected to the DP signal line 7 and the DN signal line 8. In addition, the control unit 1 can grasp the configuration of all the control and monitoring data via the parent station 6. Further, in the first diagram, although the management sub-stations 10a and 10b are included in the configuration of the photodetector 11, they may be separated from the photo-inductance detector 11.

The structure of the photodetector is shown enlarged in Fig. 3. As shown in Fig. 3, the photodetector 11 is connected to a plurality of sensing portions 11a and 11b composed of a pair of substation output unit 12a and substation input unit 12b. In addition, the number of sensing units is not limited, and the required number can be connected according to needs. The photo-sensing device also connects a plurality of sensing units, but only two sensing units are indicated on the third figure. unit.

The management substation 10a, the management substation 10b, and the sensing portion 11a are connected by the bridge wiring 13, and the sensing portion 11a and the sensing portion 11b of the next segment are connected by the inter-substation connection 34. Further, the sensing units of the subsequent sections of the sensing unit 11b are connected by the inter-substation connection 34 in the same manner.

The connector 33 is used by the connection of the bridge wiring 13 or the sub-station connection 34. To simplify the connection. Further, in the case where the plurality of sub-station connections 34 are equally spaced, the length of the inter-substation connection 34 is normalized to simplify wiring, and in the case of not being equally spaced, by connecting the sub-station 34 The length is matched with the interval to simplify wiring work and connection work.

The management substation 10a is a management substation on the light projecting side, and sends a serial connection signal to a plurality of substation output units 12a that are connected in series to the management substation 10a, and sets an operation sequence of the plurality of substation output units 12a. On the other hand, the management substation 10b is a management substation on the light receiving side. The serial sequence signal is sent to a plurality of substation output units 12b connected in series to the management substation 10b, and the operation timing of the plurality of substation output units 12b is set.

The sensor units 11a and 11b which are the sub-station output unit 12a of the light projecting unit and the sub-station input unit 12b that is the light-receiving unit are themselves transmissive sensors, and the subject 35a is accommodated in the sub-station output unit 12a and the sub-unit. Between the station input units 12b. The substation input unit 12b of the sensor unit 11a has the first light receiving element PD1d received from the light projecting element LD1d of the substation output unit 12a and reaches the substation input unit 12b without crossing the subject 35a. The optical signal and the second light receiving element PD1u receive a light projecting signal that reaches the substation input unit 12b when intersecting with the subject 35a from the light projecting element LD1d. Further, the substation output unit 12a includes the second light projecting element LD1u in addition to the light projecting element LD1d, and is arranged such that the light projecting signal reaches the second light receiving element PD1u without crossing the object 35a, and When the subject 35a crosses, the first light receiving element PD1d is reached. The sensing portion 11b and the like connected to the lower portion of the sensing portion 11a are also configured in the same manner. In the following description, the numbers of the light-emitting elements and the light-receiving elements are given 1 to the first-stage sensing portion 11a, 2 to the next-stage sensing portion 11b, and n to the n-th photo-inductor 11n. Therefore, for example, the second light projecting element of the sensor unit 11b is LD2u, and the second light projecting element of the sensor unit 11n is LDnu.

The light-emitting signal from the light-emitting element LDnd to the first light-receiving element PDnd is a light-receiving signal that is not blocked by the object 35a, and is a reference signal that is compared with the case where the light-emitting signal is shielded by the object 35a. In addition, the light-emitting signal obliquely dispersed from the light-emitting element LDnd to the second light-receiving element PDnu is blocked by the object 35a, and the light-receiving signal of the second light-receiving element PDnu is attenuated, and becomes a detection signal of a minute level. Then, the level difference between the reference signal and the detection signal is compared, and the presence or absence of the information of the subject 35a is detected. Therefore, there is a feature that is hard to be affected by the periphery of the light receiving element.

The detection determination based on the comparison of the reference signal and the detection signal is performed at the light projection timing of the light projecting portion. Further, the timing for performing the detection determination is not limited, and may be performed by, for example, a timer operation built in each of the sensing units, or may be performed after all the sensing units are patrolled. However, when the detection timing of the light projection timing of the light projecting unit is compared with the detection signal and the detection signal, the response time of the detected object is shortened as compared with the case where the detection determination is performed after all the sensing units are patrolled. , and can achieve high speed response speed. In addition, the details of the detection judgment will be described later. In addition, when the detection determination is performed by the timer operation built in each of the sensing units, the area in which the memory retention reference signal and the detection signal are set is set in advance, and the comparison is performed by the substation input unit 12b, and the memory holding area will be described later. .

On the other hand, the light projection signal from the second light projecting element LDnu to the second light receiving element PDnu is a light receiving signal that is not blocked by the object 35a, and is compared with the case where the light projecting signal is shielded by the object 35a. In the reference signal, the light-emitting signal obliquely dispersed from the second light-emitting element LDnu to the first light-receiving element PDnd is blocked by the detector 35, and the light-receiving signal of the first light-receiving element PDnd is attenuated to become a minute level detection signal. Therefore, a pair of the light projecting element LDnd and the first light receiving element PDnd, and a pair of the light projecting element LDnd and the second light receiving element PDnu are the first group, and the second light projecting element LDnu and the first light receiving element PDnd are A pair and a pair of the second light projecting element LDnu and the second light receiving element PDnu are used as the second group, and the presence or absence of the information of the object obtained from the first group and the information obtained from the second group can be detected by double comparison. The presence or absence of information on the subject. Therefore, the subject 35a can be detected with the detection accuracy of the highly reliable sensor. Further, the comparison of the level difference between the reference signal of the first group and the detection signal is performed at the light projection timing of the light projecting element LDnd, and the comparison of the level difference between the reference signal of the second group and the detection signal is performed. 2 The light projection timing of the light projecting element LDnu is performed.

As described above, the management substation 10a and the management substation 10b each transmit a serial signal (hereinafter sometimes referred to as a TDn signal) to each of the subsequent substation output unit 12a and the substation input unit 12b at the same timing. The substation input unit 12b or the substation output unit 12a receives the address timing of the own station transmitted based on the TDn signal. Further, as described above, since the management sub-stations 10a and 10b are connected to the DP signal line 7 and the DN signal line 8, respectively, the TD0 signal for determining the operation timing of the photo-detector 11 can be generated from the transfer clock signal to be described later. Therefore, even if the substation output unit 12a and the substation input unit 12b are long distances, the management substation 10a, 10b generates its own address timing, and can be supplied to the paired substation output unit 12a and the substation input unit 12b. The serial signal is sent at the same time.

The substation input unit 12a or the substation output unit 12a that has received the TD0 signal generates an address sequence of the next substation input unit 12b or the substation output unit 12b that is connected in series between the subsequent inter-substation connections 34. For example, the address sequence of the plurality of substation output units 12a is set to #A0, #A1, #A2, ..., for example, the address timing of the plurality of substation input units 12b is set to #B0, #B1, #B2. In the case of ..., the substation output unit 12a of #A0 that receives the concatenation signal (TD0 signal) from the management substation 10a outputs the output signal from the light projecting element to the substation input units 12a, 12b at the timing of the TDn signal. Cast light. The substation input unit 12b that receives the #B0 of the concatenated signal (TD0 signal) from the management substation 10b receives the light emission signal from the light receiving element at the timing of the TDn signal. In this manner, the substation output unit 12a of #A0 and the substation input unit 12b of #B0 operate in pairs. Then, the substation output unit 12a of #A1 of the substation output unit 12a of the #A0 and the substation input unit 12b of the #B1 of the substation input unit 12b of the #B0 are also projecting and receiving light at the same timing in the same manner. In other words, in the present embodiment, the plurality of pairs of sub-station output units 12a and sub-station input units 12b constitute a multi-optical-axis photo-inductor that sequentially switches the timing of the serial signal (TDn signal) and detects the detected object. . Then, whether or not there is a subject between the substation output unit 12a of the light projecting unit and the substation input unit 12b which is the light receiving unit is detected based on the intensity change of the light receiving signal.

Here, as shown in Fig. 1, in the photo-sensing system, since a plurality of photo-inductors 11 composed of a series of sensing portions 11a, 11b, ... are connected, they are paired (same sensing) The address of the management substation 10a, 10b of each of the substation output unit 12a and the substation input unit 12b (meaning the address for distinguishing the plurality of photodetectors 11) must be the same, and the substation output unit 12a The serial signals (from the TD1 signal to the TDn signal) generated by the respective management sub-stations 10a and 10b of the sub-station input unit 12b are at the same timing from the sub-station output unit 12a of #A0 to #An to #B0 to #Bn. The substation input unit 12b transmits the timings of the light projection and the light reception in synchronization. In addition, in the second drawing, the substation input unit 12a of #An is turned to the substation input unit 12b of #Bn (from the substation output unit 12a of #A0 to the substation input unit 12b of #B0, and the child of ##1 The light projection signal (arrow) written by the station output unit 12a to the substation input unit 12b of #B1, etc., indicates that the plurality of substation output units 12a and the substation input unit 12b are simultaneously projecting at the timing of the serial signal. Received light.

Figure 4 is a functional block diagram of the management substation in the photo-sensing system, and Figure 5 is a system block diagram of the management sub-station. Further, since the management sub-station 10a to which the sub-station output unit 12a is connected is the same as the functional block diagram of the management sub-station 10b to which the sub-station input unit 12b is connected, both the fourth and fifth figures show the management. The symbol of the substation is set to 10.

As shown in Fig. 4, the DP signal line 7 and the DN signal line 8 are connected to the management substation 10 via DP and DN connection terminals. In the management substation 10, first, power is generated by a power supply unit composed of a capacitor and a diode for obtaining power of the own station from the transmission signal, and the transmission signal is from the DP signal line 7, the DN signal line 8. It was transmitted and overlapped with electricity. The power superposed by the signal lines charges the capacitor via the diode to obtain the power supply voltage Vcc. This power supply voltage Vcc is supplied as a power source in the management substation 10. The wiring is omitted in such a manner that the power is superimposed on the transmission signal to obtain the power of the own station, and the so-called wiring is realized. At the same time, the management substation 10 extracts the CK signal from the DP signal line 7, the DN signal line 8, and hands it to the MCU 15. Further, the management substation 10 has an address setting 14 and uses the address setting function to perform its own address setting.

The MCU 15 analyzes the input and output signals based on the clock signal CK included in the transmission signal transmitted via the DP signal line 7 and the DN signal line 8, and holds the data information of each substation in the memory. The clock signal CK includes a long period start signal and a short period transfer clock. After the MCU 15 recognizes the start signal, it counts the number of transmission clocks and sets the time coincident with the address set in the address setting 14 of the own station address as the own station operation timing. In the management substation 10, the address timing of the own station is obtained from the CK signal according to the transmission clock, and the TD0 signal is used as a serial signal from the Tout terminal to the substation input unit 12b or #A0 of #B0 which is subsequently managed by the substation 10. The substation output unit 12a sends out. The MCU 15 is composed of a CPU 18, a RAM 19, and a ROM 20, and operates in accordance with a flow of a program flow chart to be described later based on a program stored and stored in the ROM 20. The CPU 18 has an internal clock generating circuit and performs control in the MCU 15 in accordance with this internal clock.

The DP signal line 7 and the DN signal line 8 constituting the bridge wiring 13 or the inter-substation connection 34, and the string wiring 17 for transmitting the TDn signal are as described above, and the sub-station input portion 12b or # of the subsequent #B0 is utilized by the connector 33. The substation output unit 12a of A0 is connected, and has a structure in which wiring work can be easily performed.

As shown in Fig. 5, the CPU 18 is connected to the RAM 19 and the ROM 20 by the internal bus of the MCU 15, and has an internal clock for exchanging data with the RAM 19 and the ROM 20 in accordance with the clock timing. Further, the CPU 18 is connected to the I/O bus bar 21. When the MCU 15 is initialized by the initialization program in the ROM 20 at the same time as the startup of the power supply, the system starts operating using the program PRG1 stored in the ROM 20. The RAM 19 has a data area, holds the data obtained from the CK signal, and at the same time, the timing of the ADRS signal received from the address setting unit, and the Tout signal of the serial signal to the subsequent substation respectively passes through the I/O bus 21 Send and receive data with the outside.

Fig. 6 is a system configuration diagram of the output unit of #An's substation, and Fig. 7 is a system block diagram of the substation output unit. In addition, the same reference numerals are given to components having the same functions as those of the management substation.

As shown in Fig. 6, the substation output unit 12a is also generated similarly to the management substation 10, and the own station power is generated from the transmission signals transmitted via the DP signal line 7 and the DN signal line 8. Next, the substation output unit 12a of the #A0 connected to the management substation 10a receives the TD0 signal which is the serial signal from the Ti0 terminal 27 from the management substation 10a, and proceeds to the substation output unit 12a of the following #A1 via the Tout terminal 24. Send the TD1 signal. Similarly, the sub-station output unit 12a of #An receives the TDn signal which is the concatenated signal from the Tin terminal 27 from the sub-station output unit 12a of #An+1, and goes to the sub-station of #An+1 via the Tout terminal 24 The output unit 12a sends a TDn+1 signal. In other words, the substation output unit 12a connected in the next stage outputs a serial signal of 1 to the address of the own station as a TDn signal. The MCU 15 has its own clock signal generating circuit, and performs I/O control via the RAM 19, the ROM 20, and the I/O bus bar 21 based on the clock signal.

The substation output unit 12a that has received the TDn signal transmits a signal from the Ld terminal 32 to the light emitting diode LDnd at the timing of receiving the TDn signal in the order of the serial signal sent from the management substation 10a, and emits a signal. The polar body LDnd generates a first light projecting signal. On the other hand, after the first light projecting signal is generated, a signal is sent from the LU terminal 30 to the light emitting diode LDnu to generate a second light projecting signal. Further, although the LU terminal 30 and the light-emitting diode LDnu are surrounded by a broken line, this means that it can be omitted according to the embodiment. An embodiment in which the light-emitting diode LDnu is omitted will be described later.

As shown in Fig. 7, the CPU 18 executes the program based on the unique internal clock signal, and appropriately transmits and receives data to and from the RAM 19 and the ROM 20 via the system. The CPU 18 is connected to the I/O bus bar 21. When the MCU 15 is initialized by the initialization program in the ROM 20 at the same time as the startup, the system starts operating using the program PRG2L stored in the ROM 20. Further, the MCU 15 has a data area in the RAM 19, receives the CK signal or the TDn signal from the Tin terminal 27 via the I/O bus bar 21, and performs an output operation of the Tout terminal 24, the LU terminal 30, and the Ld terminal 32, and performs external operation. Signal exchange. The CPU 18 monitors the CK terminal 22, confirms that the TDn signal which is the light projection timing of the own station has been taken in from the Tin terminal 27, and sends a signal from the Ld terminal 32 to the light emitting diode LDnd to generate the first light projection signal, and then from the LU. The terminal 30 sends a signal to the light emitting diode LDnu to generate a second light projecting signal. Here, the LU terminal 30 and the light-emitting diode Ldnu are also indicated by broken lines and may be omitted according to the embodiment.

Fig. 8 is a system configuration diagram of the substation input unit, and Fig. 9 is a system block diagram of the substation input unit, and shows a signal busbar connecting the circuit elements constituting the substation input unit in a mode. In addition, as in the sixth and seventh figures, the same components as those having the same functions as those of the management substation are denoted by the same reference numerals.

As shown in Fig. 8, the substation input unit 12b is connected to the DP signal line 7 and the DN signal line 8 via DP and DN connection terminals. Similarly to the management substation 10 or the substation output unit 12a, the substation input unit 12b generates electric power of the own station from a transmission signal in which the power supply voltage is superimposed. The CK signal, which is the input signal of the MCU 15 and is the transfer clock signal of the sensing system, is received, and the TDn signal is received from the Tin terminal 27, and the input processing is performed at this timing, and the TDn+1 signal is sent from the Tout terminal 24. Further, the A/D converter 16 converts the received light signal (analog signal) received from the light-emitting diodes PDnu and PDnd of the light-receiving element into a digital signal, and serves as data of the input signal ADATu signal and data of the ADATd signal. The memory is kept in the RAM 19. The CPU 18 calculates the difference between the data of the ADATu signal and the data of the ADATd signal stored in the RAM 19, and stores the result of the determination of the object 35 in the memory area of the RAM 19. For example, in the sensing units 11a and 11b of Fig. 3, the subject 35 is detected. Here, in Fig. 8, the light-emitting diodes PDnu and the A/D converter 16 of the light-receiving element are also indicated by broken lines, and may be omitted according to the embodiment.

Further, the MCU 15 sends the ENu signal and the ENd signal as the effective operation signals for inputting the ADATu signal and the ADATd signal to the A/D converter u and the A/D converter d, and takes in the signals from the A/D converter u and the A/D. The signal of converter d. Further, the substation input unit 12b connected in series on the next stage side outputs a serial signal concatenated signal when the falling edge of the CK signal is counted twice from the address timing of the own station as the serial signal (TDn signal). (TDn+1 signal). Further, the light receiving signal of the light receiving element PDnd is a reference signal when it is a light receiving signal from the light projecting element LDnd, and the light receiving signal of the other light receiving element PDnu is a detection signal for detecting the presence or absence of the object.

The operation of the substation input unit 12b is determined by the program PRG2P stored in the ROM 20 shown in Fig. 9, and is initialized at the same time as the input of the power supply, and is operated in accordance with the flow of the program flow chart to be described later, and is calculated by the signal calculation described later. It is used to detect the determination of the subject 35 or the determination of the abnormality. The MCU 15 is composed of a CPU 18, a RAM 19 and a ROM 20 for transmitting and receiving data to and from the CPU 18 via an internal bus bar, and an I/O bus bar 21. The CPU 18 has its own clock signal generating circuit, and operates in accordance with the program PRG2P stored in the ROM 20 at the same time as the input of the power source. Further, the main function of the program PRG2P is to receive the CK signal as the input signal, receive the TDn signal from the Tin terminal 27, accept the ADATu signal and the ADATd signal, determine the reception of each signal, and send the output signal from the Tout terminal 24 to A/. The D converter 16 sends out the ENu signal, the ENd signal, and the output signal from the Iout terminal 31.

The transmission and reception timing of the signal will be described with reference to FIG. Figure 10 is a timing diagram of the transmitted signal.

In Fig. 10, the uppermost stage shows the transmission signals on the DP signal line 7 and the DN signal line 8 on which the power source is superimposed. At the beginning of the transmission signal, the periodic operation is performed starting from the signal STB0 which is a start bit longer than the clock period of the general photo-sensing system. That is, in the case where the data length of the address after the start bit (Start Bit) is 1 bit, as shown in FIG. 10, the 1st bit becomes the address 1 (ADRS1), and the 2nd bit becomes the bit. Address 2 (ADRS2), only the number of sub-station input units or sub-station output units, and then back to the start bit (Start Bit). The address data in the case where the data length of the address has a width becomes the division of the data of the address width, and here, the case where the data length of the address is one bit is indicated. The CK signal of the second stage is a transfer clock signal having a peak value from 0 to 5V. The next TD0 signal indicates the TD0 signal sent from the management substation 10 after the start bit (Start Bit).

As shown in Fig. 10, in the case where the data length of the address is 1 bit, after the TD0 signal, each signal from the TD1 signal to the TDn-1 signal is connected as a serial signal every 2 bits. Further, the LD1d signal rises in synchronization with the falling edge of the CK signal, and becomes a half-clock projection signal. In the subsequent transfer clock cycle, the LD1u signal rises to become a half-clock spread signal. And in the subsequent transmission clock cycle, the LD2d signal rises to become a half-clock projection signal. As before, the LDnu signal rises. The LDnu signal also becomes a half-clock projection signal. The signal reflected or transmitted by the light-emitting signal on the object to be detected is received by the light-receiving element, and the PD1d signal, the PD1u signal, the PD2d signal, and the PD2u signal are generated, and thereafter, the PDnu signal is generated by the PDnu signal. The received light signal PD1d signal is generated as a result of receiving the light emitting signal LD1d or LD1u signal, and then the PD1u signal is also generated as a result of receiving the light emitting signal LD1d or LD1u signal. The PD1d signal and the PD1u signal also include signals generated when a light projecting signal that intersects with the object is received. The received light signal PD2d signal is also generated as a result of receiving the light projecting signal LD2d or LD2u signal, similarly to the PD1d signal. The PD1d signal and the PD1u signal also include signals generated when a light projecting signal that intersects with the object is received. And to the PDn signal, the received light signal is generated as a result of receiving the LDnd or LDnu signal, and each of the received light levels is memorized in the memory area. In the PD1d signal to the PD2u signal in Fig. 10, the portion where the peak value is low indicates the state in which the light projection signal is attenuated due to the subject.

Next, the specific operation of the signal reception and signal output at the management substation will be described in accordance with the flow of the program PRG1. Figure 11 is a flow chart of the management subroutine program PRG1.

The program PRG1 is started at the rising edge of the power supply, and the initial processing S1 is performed. Next, it is determined whether or not the CK signal of the transfer clock is the start bit (S2). The address counter is incremented by 1 at the falling edge of the next clock CK signal (S3), and it is determined whether it is the address setting value of the management substation (S4). In the case where the address of the management substation is not set, the address counter is incremented by 1 (from S3 to S4) on the falling edge of the next clock CK signal to the address of the management substation. In the case of the address setting value of the management substation, the Tout signal (the output signal from the Tout terminal 24, the following expression about "signal" may be the same expression) is set to "on" (S5), on the next clock CK. The falling edge of the signal adds 1 to the address counter (S6), and then determines whether it becomes the address setting value +2 (S7). If it is not the address setting value +2, it returns to the top of step S6, if it is the address setting value. +2, set the Tout signal to "off" and return to the top of step S2. In this way, the program inside the management substation operates according to the flowchart.

Next, the specific operation of the signal reception and signal output at the substation output unit will be described in accordance with the flow of the program PRG2L. Fig. 12 and Fig. 13 are flowcharts of the substation output unit program PRG2L.

The program PRG2L is started at the rising edge of the power supply, and the initial processing S9 is performed. Next, it is determined whether or not the CK signal (hereinafter referred to as CK in the following description) of the transfer clock is the start bit (S10). The address counter is incremented by 1 at the falling edge of the next clock CK signal, and it is determined whether or not the Tin signal is "on" (S11). If the Tin signal is not "on", the address counter is incremented by one, and the judgment of whether the Tin signal is "on" is repeated (S11). When it is confirmed that the Tin signal is "on", the value of the address counter is set to the address value (S11). Next, LDnd is set to "on" (S13). It is determined whether CK is "on" (S14), and if CK is not "on", the process returns to the top of step S13. If CK is "on", LDnd is set to "off" (S15). The address counter is incremented by 1 at the falling edge of the next clock CK signal (S16). Next, set LDnu to "on" (S17). Next, it is determined whether CK is "on" (S18), and if CK is not "on", the process returns to the top of step S17. If CK is "on", set LDnu to "off".

Next, the address counter is incremented by 1 at the falling edge of the next clock CK signal (S20). Next, it is judged whether or not the address counter is (address value + address data width 2) (S21). If it is (address value + address data width 2), the Tout signal is set to "on" (S22), and if not (address value + address data width 2), the process returns to the top of step S20. The address counter is incremented by 1 at the falling edge of the next clock CK signal (S23). It is judged whether or not the address counter is (address value + address data width 2 + 1) (S24). If the address counter is not (address value + address data width 2+2), it returns to the top of step S23 and waits for the next clock CK signal. If the address counter is (address value + address data width 2+2), set the Tout signal to "off" (S25). Then, it returns to the forefront of this step S10.

Next, the specific operation of the signal reception and signal output at the management substation will be described in accordance with the flow of the program PRG2P. Fig. 14 to Fig. 18 are flowcharts of the substation input unit program PRG2P.

The program PRG2P starts the power ON at the same time as the input of the system power. Next, initial processing is performed (S26). It is judged from the CK signal whether it is a start bit (STB0) (S27). In the case of the start bit (STB0), the address counter value is incremented by 1 at the falling edge of the next clock CK signal (S28). If it is not the start bit (STB0), it returns to the top of step S27. Next, it is judged whether or not the Tin signal is "on" (S29). If the Tin signal is not "on", it returns to the forefront of step S28 and waits for the next clock CK signal. If the Tin signal is "on", the address counter value is stored in the address value memory address (S30). Next, the operation of the A/D converter d and the A/D converter u is performed (S31).

Then, the ADATd which is the data of the A/D converter d is used as the ADATndd memory (S32).

Further, ADATu which is the data of the A/D converter u is used as the ADATnud memory (S33).

Next, it is judged whether or not the object detection data Dna "on/off" is "on" (S34). If the object detection data Dna "on/off" is not "on", set the Iout signal to "off" (S35). On the other hand, if the object detection data Dna "on/off" is "on", the Iout signal is set to "on" (S36). That is, at the address of step S30, the object detection data Dna "on/off" information is transmitted from the substation input unit 12b to the parent station 6.

Next, as shown in Fig. 15, the address counter value is incremented by 1 at the falling edge of the next clock CK signal (S37). And the Iout signal is set to "off" (S38). Next, the operation of the A/D converter d and the A/D converter u is performed (S39), and the ADATd which is the data of the A/D converter d is stored as ADATndu (S40). Further, ADATu which is the data of the A/D converter u is used as the ADATnuu memory (S41). Next, it is judged whether or not the abnormality detection data An "on/off" is "on" (S42). If the abnormality detection data An "on/off" is not "on", the Iout signal is set to "off" (S43).

If the abnormality detection data An "on/off" is "on", the Iout signal is set to "on" (S44). Next, Tout is set to "on" (S45). The address counter value is incremented by 1 at the falling edge of the next clock CK signal (S46), and the Iout signal is set to "off" (S47). Next, it is judged whether or not (address value + address data width 2+2) (S48). If not (address value + address data width 2+2), return to the top of step S46. If (address value + address data width 2+2), set Tout to "off" (S49). That is, the abnormality detection data An "on/off" information is transmitted from the substation input unit 12b to the parent station 6 at the address of step S37.

Next, as shown in Fig. 16, it is judged whether or not it is ADATnuu≧S (S50). Here, S is a threshold data for determining that the ADATnuu which is a reference signal that is not masked by the subject is a predetermined value or more.

In the case of ADATnuu≧S, the straight logic determination value Snu "on/off" (the logical signal based on the comparison between the reference signal of the second group and S) is set to "on" (S51). If it is not ADATnuu≧S, set Snu "on/off" to "off" (S52).

Next, it is judged whether or not it is ADATndd≧S (S53). Here, S is a threshold data for determining that the ADATndd which is a reference signal which is not blocked by the subject is a predetermined value or more.

In the case of ADATndd≧S, the straight logic determination value Snd "on/off" (the logical signal based on the comparison of the reference signal of the first group and S) is set to "on" (S54). If it is not ADATndd≧S, set Snd "on/off" to "off" (S55).

Next, as shown in Fig. 17, the calculation result of [ADATnuu-ADATndu] is memorized in ΔADATnd (S56).

Further, the calculation result of [ADATndd-ADATnud] is memorized in ΔADATnu (S57).

Then, it is judged whether or not it is ΔADATnd≧C (S58). Here, C is a threshold data for judging that the ADMTnuu which is the reference signal and the level difference of the ADATndu which is the detection signal are predetermined values or more.

In the case of ΔADATnd≧C, the cross logic determination value Cnd "on/off" (the logic signal based on the comparison between the reference signal of the second group and the level difference of the detection signal and C) is "on" (S59). If it is not ΔADATnd≧C, the cross logic determination value Cnd "on/off" is set to "off" (S60). Similarly, it is judged whether or not it is ΔADATnu≧C (S61). Here, C is a threshold data for judging that the ADMTndd of the reference signal and the level difference of the ADATnud of the detection signal are equal to or greater than a predetermined value.

In the case of ΔADATnu≧C, the cross logic determination value Cnu "on/off" (the logic signal based on the comparison between the reference signal of the first group and the level difference of the detection signal and C) is "on" (S62). If it is not ΔADATnu≧C, the cross logic determination value Cnu "on/off" is set to "off" (S63).

Then, as shown in Fig. 18, the object detection data Dne "on/off" is set to "off", and the object non-existence detection data Dna "on/off" is set to "off" (S64). Next, the judgment of the formula (1) is calculated for the following logic (S65).

[Math 1]

Snd × Cnu × Cnd × Snu =" on "...(1)

If it is "on", the object detection data Dne "on/off" is set to "on" (S66). If it is not "on", it jumps to step S67. The judgment of the formula (2) is calculated for the following logic (S67).

[Math 2]

: Anti-Logic of Cnu

: The inverse logic of Cnd

When the logic calculation formula (2) is satisfied, the object non-existence detection data Dna "on/off" is set to "on" (S68). If it is not "on", it jumps to step S69. The equation (3) is judged (S69) for the following logic.

[Math 3]

: Dna 's inverse logic

: Dne 's inverse logic

When the logic calculation formula (3) is satisfied, the abnormality detection data An "on/off" is set to "off" (S70), and the process returns to the top of step S27.

When the equation (3) of the logic calculation is not satisfied, the abnormality detection data An "on/off" is set to "on" (S71), and the process returns to the forefront of step S27.

From the step S50 to the step S71, the calculation processing for determining the presence or absence of the object to be detected is described, and the outline of the logic determination will be described with reference to Fig. 19. If the straight logic decision value Snu "on/off" is "on" and Snd "on/off" is "on", and the cross logic determination value Cnu "on/off" is "on" and Cnd "on/off" is "on" can detect the detected object. Further, if the straight logic determination value Snu "on/off" is "on" and Snd "on/off" is "on", and the cross logic determination value Cnu "on/off" is "off" and Cnd "on/off" If it is "off", it can detect that there is no object to be detected. When the logical decision value is other than the other logic, an abnormal state is detected.

The calculation process will be described using the #Bn (nth) substation input unit 12b as an example. Further, in the following description, the Δ (triangle) symbol indicates differential data.

The difference calculation result between the nth reference signal and the nth detection signal is set to ΔADATnd. When the reference signal of the nth second group is set to ADATnuu, and the detection signal of the nth second group is set to ADATndu, the memory holds ΔADATnd=ADATnuu-ADATndu.

When the reference signal of the nth first group is set to ADATndd, and the detection signal of the nth first group is set to ADATnud, the memory holds ΔADATndu=ADATndd-ADATnud.

If the ADATnuu of the reference signal of the nth second group is larger than the threshold data S for judging that it is a predetermined value or more, the straight logic determination value Snu "on/off" state becomes "on", and the nth number is judged. The reference signals of the two groups operate normally.

If the ADATnuu of the reference signal of the nth second group is smaller than the threshold data S for judging that it is a predetermined value or more, the state of the straight logic determination value Snu "on/off" becomes "off", and the nth number is judged. The reference signals of the two groups did not operate normally.

If the ADATndd of the reference signal of the nth first group is larger than the threshold data S for judging that it is a predetermined value or more, the state of the straight logic determination value Snd "on/off" becomes "on", and the nth number is judged. The reference signal of one group operates normally.

If the ADATndd of the reference signal of the nth first group is smaller than the threshold data S for judging that it is a predetermined value or more, the state of the straight logic determination value Snd "on/off" becomes "off", and the nth number is judged. The reference signal of group 1 does not operate normally.

Further, when ΔADATnd is larger than the threshold data C for determining that the value is equal to or greater than the predetermined value, the cross logic determination value Cnd "on/off" state becomes "on", which means that the subject is present in the second group.

In addition, when ΔADATnd is smaller than the threshold data C for determining that the value is equal to or greater than the predetermined value, the cross logic determination value Cnd "on/off" state becomes "off", which means that the subject does not exist in the second group.

Further, if ΔADATnu is larger than the threshold data C for judging that it is a predetermined value or more, the cross logic determination value Cnu "on/off" state becomes "on", which means that there is a possibility that the subject exists in the first group. Sex.

Further, if ΔADATnu is smaller than the threshold data C for judging that it is a predetermined value or more, the cross logic determination value Cnu "on/off" state becomes "off", meaning that there is no subject in the first group. possibility.

When the logical value of the following formula (4) is "on", the object detection data Dne "on/off" is set to "on". This means the state in which the subject is completely present.

[Math 4]

Snd × Cnu × Cnd × Snu ...(4)

When the logical value of the equation (4) is "off", the object detection data Dne "on/off" is still "off". This means a state in which the subject is completely absent.

The "on" and "off" states of the Dne "on/off" are memorized.

When the logical value of the following formula (5) is "on", the object non-existent detection data Dna "on/off" is set to "on". This means a state in which the subject is completely absent.

[Math 5]

: Anti-Logic of Cnu

: The inverse logic of Cnd

When the logical value of the equation (5) is "off", the object detection data Dna "on/off" is still "off". This means that the subject is not in a non-existent state.

The "on" and "off" states of the Dna "on/off" are memorized. In other words, the logic of the object detection data Dne "on/off" indicating that the object is completely present and the object indicating that the object is completely absent does not have the detection data Dna "on/off" become mutually exclusive.

When the mutual exclusion logic of the equation (6) of the mathematics is "on", the abnormality detection data An "on/off" is set to "off".

[Math 6]

: Dna 's inverse logic

: Dne 's inverse logic

When the mutual exclusion logic of the equation (6) of the mathematics is not "on", the abnormality detection data An "on/off" is set to "on". In other words, when the object detection data Dne "on/off" and the logic of the object non-existent detection data Dna "on/off" are not mutually exclusive, the abnormality detection data An "on/off" is set to "on". When the abnormality detection data An "on/off" is "on", it indicates a failure state of the light projecting unit 36 and the light receiving unit 37, or a state in which the abnormality of the object to be detected is maintained.

Figure 20 is a RAM memory map at the memory of the input of the substation of #Bn. In this figure, the data is arranged from the data in the lowermost channel to the n channel, and the data items are the signal data (A/D converted data) and crossover of the light-emitting diode (light-receiving element) from the left. Differential data, straight logic decision data, cross logic decision data, object detection data, and anomaly detection data. These data are the memory address memories that the CPU 18 makes for the RAM 19 each time.

Fig. 21 is a view showing the names of the respective materials of the calculation data at the sub-station input unit of #Bn. In this figure, as in the 20th figure, it is an arrangement of data from the calculation data of the first channel located at the lowermost stage to the n channel. From the left, the data items are the sequential illumination state of the emitter LD, the signal data of the light-emitting diode (light-receiving element), the cross-difference data, the straight logic determination data, the cross logic determination data, the object detection data, and the anomaly detection data. These data are also the memory address memory that the CPU 18 makes for the RAM 19 each time.

In the photo-sensing system, as described above, the pair of the light-emitting element LDnd and the first light-receiving element PDnd and the pair of the light-emitting element LDnd and the second light-receiving element PDnu are set to the first group, and the second projection is performed. A pair of the optical element LDnu and the first light receiving element PDnd and a pair of the second light projecting element LDnu and the second light receiving element PDnu are set to the second group, and the object obtained from the first group is detected in a double alignment. The presence or absence of information and the presence or absence of information on the subject obtained from the second group. However, it is also possible to detect using only one of the first group or the second group without taking into consideration the required accuracy. In this case, the substation output unit may have only one light projecting element.

In addition, the sensor unit 11n used in the photo-sensing system is combined and unitized by the light-projecting unit 36 constituting the sub-station output unit 12a and the light-receiving unit 37 constituting the sub-station output unit. In the case of unitization, since the interval of each segment can be freely set, there is an advantage that the range of application can be expanded.

Further, when the presence or absence of the subject 35a is not detected, it is also possible to detect an abnormal state of the subject 35a, a sensor failure, or both. The logical calculation in this case may be performed by each substation input unit 12b, or may be performed by the parent station 6 or the control unit 1.

Further, in the photo-sensing system, the two light-receiving elements PDnu and PDnd are used as the sub-station input unit 12b. However, as described above, one of them may be omitted. In other words, as the substation input unit 12b, one having only one light receiving element can be used. Fig. 22 is a view showing the configuration of another embodiment of the photo-electrical sensor of the present invention. It is to be noted that the same reference numerals are given to the portions that are substantially the same as those in the first embodiment to the first embodiment, and the description thereof will be simplified or omitted. Further, since the photo-sensing system using the photo-sensing device has substantially the same configuration as the photo-sensing system shown in FIGS. 1 to 21, the illustration of the system is omitted.

The photodetector 11 shown in Fig. 22 is connected to a plurality of sensing units including a substation output unit 12a having a single light projecting element LDnd and a substation input unit 12b having a single light receiving element PDnd. There is no limit to the number of sensing units, and the required number can be connected as needed. Although the photo-sensing device is also connected to a plurality of sensing units, only the five sensing units are indicated on the right in FIG. 11a, 11b, 11c, 11d, and 11e (hereinafter, these are collectively referred to as the sensing unit 11 in some cases).

Further, the photodetector 11 is connected to the DP signal line 7 and the DN signal line 8 via the management sub-station 10a on the light-emitting side and the management sub-station 10b on the light-receiving side, and can be controlled via the parent station 6. The management sub-station 10a on the light-emitting side and the management sub-station 10b on the light-receiving side are connected to the sensing unit 11a via the bridge wiring 13, and are connected in series from the sensing unit 11a to the sensing unit 11e by the inter-substation connection 34. Further, each of the sensing units 11 is connected to the DP signal line 7 and the DN signal line 8, and sends a detection signal of the presence or absence of the object to the DP signal line 7 and the DN signal line 8 from each of the sensing units 11.

In the photo-detector 11, the light-emitting signal from the light-emitting element LDnd to the light-receiving element PDnd of the same sensing portion 11n becomes a light-receiving signal that is not blocked by the object 35a, that is, a reference signal. Further, a light-emitting signal obliquely dispersed from the light-emitting element LDnd to the light-receiving element PD(n+1)d of the sensing portion 11n+1 (upper side) adjacent to the sensing portion 11n having the light-emitting element LDnd is a subject 35a is shielded, and the light receiving signal of the light receiving element PD(n+1)d is attenuated, and becomes a minute level detection signal. Then, the level difference between the reference signal and the detection signal is compared, and the presence or absence of the object 35a is detected. Further, the sensing portion adjacent to the sensing portion 11n having the light emitting element LDnd may be the sensing portion 11n-1 (the first stage side). However, since there is no difference in mass between the sensing portions of either one, only the case of the sensing unit 11n+1 will be described below.

In this manner, even if the substation input unit 12b does not have two light receiving elements, it can be used as the case of using the substation input unit having the two light receiving elements by using the light receiving elements of the adjacent substation input unit 12b. .

Each of the management sub-station 10a and the management sub-station 10b transmits a serial signal (hereinafter sometimes referred to as a TDn signal) to the respective sub-station output unit 12a and the sub-station input unit 12b at the same timing. The substation input unit 12b or the substation output unit 12a receives the address timing of the own station transmitted by the TDn signal, and outputs the serial connection signal (TDn+1 signal) to the substation input unit 12b connected in series to the next stage side. ). At this time, the TDn+1 signal which is the serial signal is output to the address of the own station when the falling edge of the CK signal is counted twice. The TDn signal is the same as the photo-sensing system shown in Figs. 1 to 21, and becomes the address timing signal of the subsequent substation output or substation input. For example, in the substation input unit 12b of the sensing unit 11b, the light receiving timing is the light projection timing of the light projecting element LD1d of the sensing unit 11a and the light projection timing of the light projecting element LD2d of the sensing unit 11b. At the light emission timing of the light projecting element LD1d, the light receiving signal of the light receiving element PD1d becomes a reference signal, and the light receiving signal of the light receiving element PD2d becomes a detection signal. Moreover, at the light emission timing of the light projecting element LD2d, the light receiving signal of the light receiving element PD1d becomes a detection signal, and the light receiving signal of the light receiving element PD2d becomes a reference signal. In other words, the sensing unit 11n receives the light receiving signal at the light emission timing of the LD(n-1)d and the light emission timing of the LDnd. The received light signal is the same as the photo-sensing system shown in Figs. 1 to 21, and the received light signal is converted into digital signal data by the A/D converter and stored in each memory area.

Further, in the photodetector 11, the presence or absence of information of the subject 35a can be detected in a double comparison. In this case, a pair of the light projecting element LDn and the light receiving element PDn of the sensing unit 11n, and a pair of light receiving elements LDn of the sensing unit 11n and the light receiving element PDn+1 of the sensing unit 11n+1 are also provided. In the first group, the pair of light projecting elements LDn+1 of the sensing portion 11n+1 and the light receiving element PDn of the sensing portion 11n, and the light projecting element LDn+1 of the sensing portion 11n+1 and the light receiving element A pair of PDn+1 may be set as the second group.

Further, since the basic configuration of the substation input unit 12b in the photodetector 11 is the same as that of the photo-sensing system shown in Figs. 1 to 21, the system configuration diagram of the substation input unit in Fig. 8 is referred to.

The substation input unit 12b omits the light receiving element PDnu indicated by a broken line in Fig. 8, and has only the light receiving element PDnd.

The adjacent sensing unit is the sensing unit 11n+1. However, when the detection is doubled, the sensing unit 11n-1 and the sensing unit 11n+1 are provided.

Next, the operation of the photodetector 11 will be described with reference to Fig. 22. First, the TD0 timing signal is sent from the management sub-stations 10a and 10b. At this time, the light-receiving element PD1d of the sensing unit 11a and the light-receiving element PD2d of the sensing unit 11b receive light by the A/D converter 16 of each sensing unit. The signal is digitized and signaled by the analog signal, and as the data level of the ADAT, the memory is kept in the respective RAM 19. At this time, the light receiving signal of the light receiving element PD1d is used as the data level of the ADATd signal, and the light receiving signal of the light receiving element PD2d is used as the data level of the ADATu signal, and is stored and held in the RAM 19. The respective CPUs 18 calculate the difference between the data level of the ADATu signal held in the RAM 19 and the data level of the ADATd, and retains the result of the presence or absence of the object to be detected 35a in the memory area of the RAM 19. In the example of the photodetector 11, it is detected that the object 35a is detected between the sensing portion 11a and the sensing portion 11b.

In Fig. 22, the subject 35b indicated by a broken line indicates that the subject to be accommodated in a normal state does not exist. The position of the subject 35b is such that the light receiving signal of the light receiving element PD2d of the sensing unit 11b is the data level of the ADATd signal, and the light receiving signal of the light receiving element PD3d of the sensing unit 11c is used as the data level of the ADATu signal, and is respectively A. The /D converter 16 performs digital signalization and is memory-held in the RAM 19. The CPU 18 of each of the sensing units 11b and 11c performs calculation processing for determining the difference between the data level of the ADATu signal memorized and held by the RAM 19 and the data level of the ADATd signal. In the example of the photo-electrical sensor, the object to be detected does not exist, and the light-emitting signals from the light projecting element LD2d of the sensing unit 11b to the light-receiving element PD2d and the light-receiving element PD3d are not attenuated. Therefore, the difference becomes a value close to 0, and the subject 35b is judged to be absent, and the result of the determination is stored in the memory area of the RAM 19.

With respect to the subject 35c, the sensing unit 11c and the sensing unit 11d perform the same operation as the sensing units 11a and 11b of the subject 35, and are detected.

The subject 35d is held in an abnormally inclined state, and the light projecting signal from the light projecting element LD4d to the light receiving element PD4d of the sensor unit 11d that is not normally blocked is in a state of being shielded by the subject 35d. On the other hand, the light projection signal from the light projecting element LD4d to the light receiving element PD5d of the sensing unit 11e is in a state of being shielded by the object 35d. Since both the reference signal and the detection signal are shielded, it is detected that the abnormality of the detected object 35d or the storage state (inclined placement) is abnormal.

Referring to Fig. 23, the timing of transmitting and receiving signals of the photodetector 11 will be described. Figure 23 is a timing diagram of the transmitted signal. In addition, since the main difference between the timing chart of FIG. 23 and the timing chart of FIG. 10 is the light projecting signal and the light receiving signal, the other signals are substantially the same, and therefore, only the light receiving signal is described here. PD1d signal, PD2d signal and PD3d signal.

The received light signal PD1d signal is generated as a result of receiving the LD1d signal or the LD2d signal, and the next received light signal PD2d signal is the received LD1d signal, LD2d and LD3d signals (not shown). The PD1d signal and the PD2d signal also include signals generated when a light projecting signal that intersects with the object is received. The subsequent received light signal PD3d signal is also generated as a result of receiving the LD2d signal, the LD3d signal (not shown), and the LD4d signal (not shown), similarly to the PD2d signal. The PD3d signal also includes a signal generated in the case of receiving a light projecting signal that intersects the object to be detected. And the PDnd signal is generated as a result of receiving the LD(n-1)d signal, the LDnd signal, and the LD(n+1) signal, and each of the received light levels is memorized in the memory area. In the PD3d signal in the figure, a portion indicated by a broken line having a low wave height value indicates a case where the object to be detected is accommodated, that is, a state in which the general light projecting signal is attenuated.

The sensor unit 11n in the photodetector is the same as that shown in FIGS. 1 to 21, and is composed of a light projecting unit 36 constituting the substation output unit 12a and a light receiving unit 37 constituting the substation output unit. Unitizer. Therefore, it is possible to freely set the interval of each segment and apply it to various thicknesses or sizes of the object to be detected, and it is possible to greatly expand the range of application in the case where the shape of the object to be detected is different.

Further, in this embodiment, the light-emitting signals from one light-emitting element are received by the two light-receiving elements, and each of the light-receiving elements generates a reference signal and a detection signal. However, it is also possible to use one light-receiving element to receive the light-emitting signals from the two different light-emitting elements at their respective time-division projection timings, and to generate the reference signal and the detection signal for each of the time-division projection timings. In this case, it is an embodiment of the second photodetector of the present invention. In the second photodetector, in addition to the above-described effects, even if the light receiving unit includes a single light receiving element, it is not necessary to transmit and receive signals to and from the adjacent light receiving unit, and the reference signal and the detection signal can be obtained. The bit difference also has the advantage of making the circuit or calculation simpler.

1. . . Control department

2. . . Output unit

3. . . Input unit

4. . . control signal

5. . . Surveillance signal

6. . . Mother station

7. . . DP signal line

8. . . DN signal line

10. . . Management substation

11. . . Photoelectric detector

11a,...,11n. . . Sensing department

12. . . Substation input unit, substation output unit

13. . . Bridge wiring

14. . . Address setting

15. . . MCU

16. . . A/D converter

17. . . String wiring

18. . . CPU

19. . . RAM

20. . . ROM

twenty one. . . I/O bus

twenty two. . . CK terminal

twenty four. . . Tout terminal

27. . . Tin terminal

30. . . LU terminal

31. . . Iout terminal

32. . . Ld terminal

33. . . Connector

34. . . Substation connection

35. . . Subject

36. . . Projection unit

37. . . Light receiving unit

Fig. 1 is a system overall view showing an embodiment of the photo-electrical sensing system of the present invention.

Figure 2 is a block diagram of the photo-sensing system.

Figure 3 is a block diagram of the photo-electrical sensor in the photo-sensing system.

Figure 4 is a functional block diagram of the management substation in the photo-sensing system.

Figure 5 is a system block diagram of the management substation in the photo-sensing system.

Fig. 6 is a system configuration diagram of the output unit of the substation in the photo-sensing system.

Figure 7 is a system block diagram of the output of the substation in the photo-sensing system.

Fig. 8 is a system configuration diagram of a substation input unit in the photo-sensing system.

Figure 9 is a system block diagram of the input of the substation in the photo-sensing system.

Figure 10 is a timing diagram of the transmitted signals in the photo-sensing system.

Figure 11 is a flow chart of the management substation program in the photo-sensing system.

Figure 12 is a flow chart of the program output of the substation in the photo-sensing system.

Fig. 13 is a flow chart showing the program of the substation output portion of the photo-sensing system of Fig. 12;

Figure 14 is a flow chart of the substation input program in the photo-sensing system.

Fig. 15 is a flow chart showing the program of the substation input unit in the photo-sensing system of Fig. 14.

Fig. 16 is a flow chart showing the program of the substation input section in the photo-sensing system of Fig. 15.

Fig. 17 is a flow chart showing the program of the substation input unit in the photo-sensing system of Fig. 16.

Fig. 18 is a flow chart showing the program of the substation input section in the photo-sensing system of Fig. 17;

Figure 19 is a logic diagram of the photo-sensing system.

Figure 20 is a RAM memory diagram of the input of the substation #Bn in the photo-sensing system.

Figure 21 is the calculation data of the input section of the #Bn substation in the photo-sensing system.

Fig. 22 is a view showing the configuration of a photo-electrical sensor according to another embodiment of the photo-sensing system of the present invention.

Figure 23 is a timing diagram of the transmitted signals of the photo-sensing system using the photo-electrical sensor.

1. . . Control department

2. . . Output unit

3. . . Input unit

6. . . Mother station

7. . . DP signal line

8. . . DN signal line

11. . . Photoelectric detector

Claims (12)

An optical sensor having a light projecting portion and a light receiving portion that are disposed opposite to each other, and detecting a space accommodated between the light projecting portion and the light receiving portion by a change in intensity of a light receiving signal of the light receiving portion The presence or absence of the object to be detected; the light receiving unit has a first light receiving element and a second light receiving element that operate in synchronization with a light emission timing signal of the light projecting unit; and the light projecting unit has a first light projecting element configured to be cast The optical signal reaches the first light receiving element without crossing the object, and reaches the second light receiving element when intersecting the object; and the second light projecting element is configured to emit a light signal When the second light-receiving element is not crossed, the second light-receiving element is reached, and when the object is crossed, the first light-receiving element is reached, and the first light-emitting element and the first light-receiving element are And a pair of the first light projecting element and the second light receiving element is a first group; a pair of the second light projecting element and the first light receiving element; and the second light projecting element The pair of the second light receiving elements is set to the second group; in the first group, the comparison is not a light-receiving signal of the first light-receiving element attenuated by the object and a level difference of a light-receiving signal of the second light-receiving element that is attenuated by the object to detect the presence or absence of the object; and, In the second group, the level difference between the light receiving signal of the first light receiving element attenuated by the object and the light receiving signal of the second light receiving element which is not attenuated by the object is compared. The presence or absence of the subject is detected, and the presence or absence of the subject obtained from the first group and the presence or absence of the subject obtained from the second group are detected in a double comparison. The optical inductance detector according to claim 1, wherein the comparison of the level difference in the first group is performed on a light projection timing of the first light projecting element, and the light is projected on the second light projecting element. Timing is performed on the comparison of the bit differences in the second group. An optical sensor having a light projecting portion and a light receiving portion that are disposed opposite to each other, and detecting a space accommodated between the light projecting portion and the light receiving portion by a change in intensity of a light receiving signal of the light receiving portion The presence or absence of the object to be detected; the light projecting unit includes: a first light projecting element that projects a light projecting signal that reaches the light receiving unit when there is no intersection with the object; and a second light projecting element that projects a light-emitting signal that reaches the light-receiving unit when the object is crossed, and a time-division light-receiving signal that is generated by receiving a light-emitting signal that is not attenuated by the object from the first light-emitting element, and The level difference of the other time-division light-receiving signal generated from the second light-emitting element due to the light-emitting signal attenuated by the object is received to detect the presence or absence of the object. A photoinductor characterized by: a light projecting unit and a light receiving unit that are disposed to face each other, and detect the presence or absence of the object to be detected in the space between the light projecting unit and the light receiving unit by the intensity change of the light receiving signal of the light receiving unit; a first light projecting element and a second light projecting element; the light receiving unit includes: a first light receiving element; and receives a light projecting signal from the first light projecting element that is not attenuated by the object, and the second light emitting signal a light projecting signal that is attenuated by the object to be detected by the light-emitting element; and a second light-receiving element that receives a light-emitting signal from the second light-emitting element that is not attenuated by the object and from the first a light projecting signal that is attenuated by the object to be detected by the light-emitting element; a pair of the first light-emitting element and the first light-receiving element; and a pair of the second light-emitting element and the first light-receiving element a first group; a pair of the second light projecting element and the second light receiving element; and a pair of the first light projecting element and the second light receiving element are referred to as a second group; Comparing the time-division light-receiving signal of the first light-receiving element that is not attenuated by the object to be detected, and the object to be detected Attenuating the level difference of the other time-division light receiving signal of the first light receiving element to detect the presence or absence of the object; and, in the second group, comparing the attenuation of the object by the second group (2) a time-division light receiving signal of the light receiving element and a level difference of another time-division light receiving signal of the second light receiving element that is not attenuated by the object to detect the presence or absence of the object; Aligning the detected object from the first group Information on whether or not there is information on the presence or absence of the subject obtained from the second group. The optical inductance detector of claim 4, wherein the comparison of the level difference is performed at a time division projection timing of the first light projecting element and the second light projecting element. An optical sensor according to claim 1, 2, 4 or 5, wherein the information on the presence or absence of the object obtained in the first group and the presence or absence of the object in the second group are The information on the presence or absence of the object is doubled, and when the presence or absence of the object is not detected, the abnormal state of the object and/or the sensor failure are detected. An optical sensor comprises a plurality of optical photodetectors as claimed in claim 1, 2, 4, 5 or 6 and detects a plurality of the detected objects. The photodetector is characterized by: Sharing the second light projecting element of the second group and the first light projecting element of the first group of the other subject, the first light projecting element of the first group of the other subject It is adjacent to the subject to be tested for the second group; the second light receiving element of the second group and the first light receiving element of the first group of the other subject are shared. An optical-inductance detector which comprises the optical-inductance detector of claim 3 in a plurality of stages, and detects a plurality of the objects to be detected. The photo-electrical sensor is characterized in that the second light-emitting element is The first light projecting element that is another object to be detected adjacent to the object to which the light projecting signal intersects is shared; the second light receiving element is shared as the other detected object The first light receiving element of the body. An optical-inductance detector according to claim 1, 3, 4, 7 or 8 wherein the pair of light projecting portions and the light receiving portion are unitized. A photo-sensing system comprising: a plurality of optical detectors according to any one of claims 1 to 9; a first management sub-station connected to the series of the light-emitting portions, and corresponding to the a second management substation connected to the light receiving unit by one of the light projecting units; the first management substation generates the light emission timing signal, and the second management substation generates a timing of the light receiving signal synchronized with the light emission timing signal signal. The optical-inductance measuring system of claim 10, wherein the plurality of light-emitting portions and the series of the light-receiving portions are connected to a common data signal line, and the information about the presence or absence of the object is communicated to the parent station. Abnormal state of the detected object and/or sensor failure information. A photo-sensing system comprising an optical detector as claimed in claim 1, 2, 4 or 5; information on the presence or absence of the object obtained in the first group and the result obtained in the second group The presence or absence of the object is double compared to the presence or absence of the object, and when the presence or absence of the object is not detected, the abnormal state of the object and/or the sensor failure are detected.