JP2007235408A - Multi-optical axis photoelectric safety device and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-optical-axis photoelectric safety device capable of switching a safety function mute and blanking or the like depending on a detection state of each optical axis. <P>SOLUTION: The multi-optical-axis photoelectric safety device is provided with a light emitting section and a light receiving section for configuring a sensing region by a plurality of optical axes, a controller section for generating a control output signal on the basis of a light incidence/light shield state of the optical axes and capable of outputting the control output signal externally, and an invalidating function for temporarily invalidating a safety function for outputting the control output signal, and also provided with a setting means for associating the light incidence/light shield state of one or more first optical axes with the invalidating function applied to one or more second optical axes, a control means for applying the invalidating function associated with the second optical axes by the setting means on the basis of the light incidence/light shield state of the first optical axes and generating the control output signal on the basis of the light incidence/light shield state of each optical axis and the invalidating function, and an output means for outputting a control signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multi-optical axis photoelectric safety device including a multi-optical axis photoelectric sensor and a control method thereof.

  The photoelectric sensor is also called a photoelectric switch, and can detect whether or not there is a detection target in the detection region. A multi-optical axis photoelectric sensor using a plurality of photoelectric sensors as a multi-optical axis is arranged in the vicinity of a device having a danger source such as a press or a folding machine, with a light projecting unit and a light receiving unit as a pair. In order to protect the safety of workers, it is used as a multi-optical axis photoelectric safety device. This multi-optical axis photoelectric safety device includes a light projecting unit in which a number of light projecting elements are arranged in a row, and a light receiving unit in which the same number of light receiving elements as the light projecting elements are arranged in a row. If a light curtain, that is, a protective barrier, is formed by the light receiving unit (hereinafter sometimes referred to as “projecting / receiving unit” collectively), and a light blocking object enters the detection area of this protective barrier, the control output signal notifies the danger. Forcibly stop the operation of danger sources such as presses and folding machines.

  The multi-optical axis photoelectric sensor basically has a safety function of outputting a control output so as to stop the danger source when any of the optical axes is shielded. However, a function for disabling the safety function is provided for all or a part of the optical axes so that the system does not stop due to the entry of a workpiece according to the normal operation. As such an invalidation function, a floating blanking function, a fixed blanking function, a muting function, and the like are known. Floating blanking is a function that does not stop the system even if one of the optical axes is shielded from light (or a predetermined number) or is turned off. This function is effective when the workpiece moves in the detection area. It is. For example, as shown in FIG. 1, when the wire 2 moves in the detection area constituted by the light curtain 1, the safety function does not function even if the wire 2 is shielded from light. The floating blanking function switches the control output to function the safety function when more light shielding occurs than the set number of optical axes.

  The fixed blanking function is a function that determines that the light-shielded state is normal. This function is effective, for example, when an obstacle such as the conveyor 3 always stays in the detection area as shown in FIG. 2, and the light curtain 1 can always be operated even if an obstacle exists.

On the other hand, the muting function is to temporarily stop the safety function while a signal from a muting device such as a sensor or a switch is being input. For example, as shown in FIG. 3, in an application in which workpieces W are transported on a conveyor 3, a plurality of muting sensors 4 are arranged along the approach path of the workpieces W, and the muting sensor 4 allows the workpieces to enter. The muting function is detected and turned on. During this time, the safety function is disabled for all optical axes or a part of the optical axes so that the apparatus does not stop, and work entry is permitted (see Patent Document 1, etc.). .
Japanese Patent Application Laid-Open No. 2004-5542

  However, the conventional multi-optical axis photoelectric sensor uniformly disables the safety function, so when the invalidation function works, all the optical axes are invalidated, and only a part of the optical axes are invalidated and the rest Control such as maintaining was not possible. In addition, the invalidation function such as mute and blanking cannot be switched according to the detection status of each optical axis of the multi-optical axis photoelectric sensor. Further, in order to use the muting function, a muting device such as a sensor and a switch is required separately, which is disadvantageous in terms of installation effort, space, and cost. In particular, the setting of the muting device requires an appropriate arrangement depending on the size of the work, and when the size of the work changes, it is necessary to readjust the position of the muting device. Furthermore, during normal operation, when any optical axis detects a workpiece, the output of the operation permission signal is stopped, so that the entire system is stopped. In the conventional multi-optical axis photoelectric sensor, since the safety-related output is one system in the entire system, it is necessary to prepare a plurality of multi-optical axis photoelectric sensors when stopping a plurality of devices individually.

  On the other hand, in the object recognition method according to Patent Document 1, whether a workpiece that has an entry permission (for example, a part of a machine) or a workpiece without an entry permission (for example, a human leg) exists in the detection region. 4, two or more moving objects in the detection region are recognized using a horizontal light grid 6 having a plurality of light blockers 5 parallel to each other as shown in FIG. Here, in order to allow a plurality of workpieces W to pass through the protection area at the same time without disabling the monitoring function, three criteria of an entry area for the workpiece W, a size of the workpiece W, and a distance between the workpieces are set. Monitor as a set. If even one of these criteria is not met, a warning signal is output and, for example, the equipment is shut down accordingly. In this method, since the workpiece size is registered in advance, only workpieces of the same size are accepted, and entry permission cannot be given to workpieces of this size. Depending on the line, it may be desirable to accept workpieces of various sizes, and when different workpieces flow on the same line, it is convenient if they can be distinguished by a multi-optical axis photoelectric sensor.

  The present invention has been made to solve such conventional problems. A main object of the present invention is to provide a multi-optical axis photoelectric safety device capable of switching a safety function of mute and blanking according to a detection state of each optical axis and a control method thereof.

  In order to achieve the above object, a multi-optical axis photoelectric safety device according to the first aspect of the present invention includes a light projecting unit having a plurality of light projecting elements for projecting light, a light projecting unit, Detected by a light receiving unit that is arranged to face each other and has a plurality of light receiving elements for receiving light projected from the light projecting unit, and a plurality of optical axes configured between the light projecting unit and the light receiving unit A multi-optical axis photoelectric safety device comprising a controller unit that constitutes a region, generates a control output signal based on the incident / shielded state of the optical axis, and is output to the outside. The apparatus includes a disabling function for temporarily disabling a safety function for outputting a control output signal, and the multi-optical axis photoelectric safety apparatus further includes a light incident / light shielding state of one or more first optical axes, Setting means for associating invalidation function applied to one or more second optical axes, and incident / shielding of the first optical axis Control for applying the invalidation function associated by the setting means to the second optical axis based on the state, and generating a control output signal based on the incident / shielding state and invalidation function of each optical axis Means and output means for outputting a control signal. Thereby, the mode of the invalidation function can be changed by the optical axis itself included in the multi-optical axis photoelectric safety device, and the entry of the workpiece can be permitted autonomously without providing a separate trigger or sensor.

  In the multi-optical axis photoelectric safety device according to the second aspect of the present invention, the first optical axis constitutes a normal workpiece shape detection area, and the second optical axis constitutes an abnormality detection area. Thereby, the mode of the invalidation function can be changed by the optical axis itself included in the multi-optical axis photoelectric safety device, and the entry of the workpiece can be permitted autonomously without providing a separate trigger or sensor.

  Furthermore, in the multi-optical axis photoelectric safety device according to the third aspect of the present invention, the setting means sets the incident / light-shielding pattern on the first optical axis constituting the normal workpiece shape detection area. The law is made available. This makes it possible to easily register a predetermined light incident / light-shielding pattern in the normal workpiece shape detection area by entering an actual workpiece and teaching it, and to ensure that the workpiece conforming to this pattern is normal and to allow entry. Can be disabled. If the registered light incident / light shielding pattern does not match, it is determined that the workpiece is abnormal, the safety function is validated, and the controlled device can be stopped by the control output signal.

  Furthermore, the multi-optical axis photoelectric safety device according to the fourth aspect of the present invention has at least one of a fixed blanking function, a floating blanking function, and a muting function as an invalidating function.

  Furthermore, the multi-optical axis photoelectric safety device according to the fifth aspect of the present invention is disposed so as to face a light projecting unit having a plurality of light projecting elements for projecting light. A light receiving part having a plurality of light receiving elements for receiving the light projected from the light projecting part, and a plurality of optical axes formed between the light projecting part and the light receiving part to form a detection region, A multi-optical axis photoelectric safety device comprising a controller unit that generates a control output signal based on a light incident / light-shielding state of an axis and can output the control output signal to the outside. The multi-optical axis photoelectric safety device further includes a workpiece detection sensor for detecting the intrusion of the workpiece along the traveling direction of the workpiece, and a workpiece detection function. Work detection sensor input times for inputting the work detection signal from the detection sensor And setting means for setting the invalidation function to be applied to a predetermined optical axis in advance, and the invalidation function set by the setting means based on the workpiece detection signal input by the workpiece detection sensor input circuit is applied. Control means for changing the optical axis, and output means for outputting a control signal. As a result, based on the workpiece detection signal of the workpiece detection sensor, the invalidation function can be demonstrated and the optical axis to which the invalidation function is applied can be changed. realizable.

  Furthermore, in the multi-optical axis photoelectric safety device according to the sixth aspect of the present invention, the disabling function includes at least one of a fixed blanking function, a floating blanking function, and a muting function, and the control means includes: Either the optical axis that enables the muting state, the optical axis that enables the floating blanking function, or the position of the optical axis that enables the fixed blanking function, the workpiece detection signal input by the workpiece detection sensor input circuit or It has a function to change based on the signal of the optical axis whose light incident / shielding state has changed. This makes it possible to effectively use various invalidation functions, for example, by changing the profile of the optical axis that has been invalidated according to the progress of the workpiece, and performing invalidation that matches the shape of the workpiece, thereby reducing the dead space. A curtain can be realized.

  Furthermore, in the multi-optical axis photoelectric safety device according to the seventh aspect of the present invention, the control means is based on the workpiece detection signal input by the workpiece detection sensor input circuit or the signal of the optical axis whose incident / light-shielding state has changed. The optical axis that activates the muting state after a certain period of time, the optical axis that activates the floating blanking function, and the optical axis that activates the fixed blanking function according to the timing at which the incident / light-blocking information of each optical axis changes. A function of changing any of the positions is provided. As a result, it is possible to predict the optical axis to be invalidated at the next timing according to the progress of the workpiece and sequentially change the optical axis that is the target of the invalidation function for the workpiece whose shape is known in advance. Accurate invalidation can be performed.

  Furthermore, the multi-optical axis photoelectric safety device according to the eighth aspect of the present invention further allows a plurality of detection areas to be specified, generates a plurality of control output signals for each detection area, and It has a detection area setting unit for assigning the optical axis to which it belongs, generates a control output signal in each detection area based on the incident / shielded state of the optical axis, and is configured so that the output means can output each control output signal. Yes. Thus, by using one multi-optical axis photoelectric safety device and assigning a plurality of optical axes included therein independently to a plurality of outputs, it is as if a plurality of multi-optical axis photoelectric safety devices are used. The same effect as the safety system can be obtained. In particular, by making it possible to control a plurality of outputs with a single multi-optical axis photoelectric safety device, it is possible to construct a safety system with ease of design with reduced wiring and low cost.

Furthermore, the control method of the multi-optical axis photoelectric safety device according to the ninth aspect of the present invention is:
Light receiving unit having a plurality of light projecting elements for projecting light, and a light receiving unit having a plurality of light receiving elements arranged to face the light projecting unit and receiving the light projected from the light projecting unit A detection region in which a plurality of optical axes are arranged in parallel with each other, and a step of arranging the detection region so that the detection region intersects or coincides with the entry direction of the workpiece, and the optical axis of the detection region is sequentially shielded. A step of setting a floating blanking function in which the blanking area in the detection area changes according to the position of the moving workpiece with respect to the optical axis previously shielded when the workpiece is loaded, Based on the incident / blocking information of the optical axis for which the ranking function is set, the floating blanking function is set for the next optical axis adjacent to the optical axis and muting is performed for the first optical axis. Or Muting or fixed blanking function sequentially from the incident light axis based on the incident light / light shielding information of the previously incident light axis when the workpiece passes through the process of setting the box blanking function And a step of returning to the operating state of the safety function. As a result, when the light is shielded according to a predetermined sequence, the safety function is invalidated so as to permit entry of the workpiece.

  According to the multi-optical axis photoelectric safety device and the control method thereof according to the present invention, the mode of the safety function can be sequentially changed according to the shape of the workpiece that enters, and the necessary workpiece can be passed without stopping the system. . In particular, the mode change trigger can be performed using the optical axis of the sensor instead of inputting from the outside such as a muting sensor. Further, the mode of the invalidation function can be sequentially changed according to the shape of the detection target detected by the multi-optical axis photoelectric safety device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a multi-optical axis photoelectric safety device and a control method thereof for embodying the technical idea of the present invention, and the present invention is a multi-optical axis photoelectric safety device. The control method is not specified as follows. In particular, the present specification by no means specifies the members shown in the claims as the members of the embodiments. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  In the present invention, the multi-optical axis photoelectric safety device includes all non-contact detectors that apply the photoelectric effect, but typically the amount of light received due to reflection, radiation or light shielding of the detection target itself to be detected. It is a photoelectric proximity switch in a narrow sense that detects the presence / absence, size, brightness / darkness, etc. of an object, depending on the size, and outputs a contact or non-contact switching output. Hereinafter, an example will be described in which a proximity switch that includes a semiconductor switching element as a photoelectric proximity switch and detects an object by either reflection of visible or invisible light or light shielding is described.

  FIG. 5 shows a block diagram of a multi-optical axis photoelectric safety device according to an embodiment of the present invention. The multi-optical axis photoelectric safety device 100 shown in this figure includes a pair of light projecting units 10, a light receiving unit 20, and a controller unit 30 for controlling them. The light projecting unit 10 is a light projecting unit in which a large number of light projecting elements 11 that project light to the detection region are arranged in a line. The light receiving unit 20 has the same number of light receiving elements 21 as the light projecting elements 11 in a line. It is the arranged light receiving unit. These light projecting and receiving units can be arranged on two or more surfaces such as both sides of the unit in addition to arranging the light projecting and receiving elements on one surface of the unit. In addition, the light projecting / receiving elements can be arranged not only in one row but also in two or more rows.

In the light projecting / receiving unit constituting the multi-optical axis photoelectric sensor, the light projecting element 11 and the light receiving element 21 constitute an optical axis, a light curtain, that is, a protective barrier is formed by a plurality of optical axes, and a desired region within the protective barrier. Set the detection area to. A control output signal is generated for each set detection region. That is, when a light shielding object (work) enters the detection area and any one of the optical axes is blocked, the controller unit 30 generates a control output signal according to the setting, and forcibly stops the operation of the controlled object. Control. As a method for generating the control output signal based on the light incident / light-blocking state of the optical axis, in addition to the method of detecting that the light-projecting state has been switched to the light-blocking state, the light-blocking state has been switched to the light-projecting state. It goes without saying that it is possible to adopt a method of detecting
(Light emitting unit)

  The light projecting unit 10 is provided with a light projecting circuit 12 for each light projecting element 11, and controls each light projecting circuit 12 with a light projecting control circuit. Further, the light projecting unit 10 includes a light projecting side communication circuit, and performs necessary data communication with the controller unit 30.

  The light projecting unit constituting the light projecting unit 10 shown in FIG. 5 includes N light projecting circuits 12 that individually drive light projecting elements 11 such as light emitting diodes (LEDs) and LDs (laser diodes), and these light projecting units. A light projecting control circuit 14 for controlling the optical circuit 12 and a light projecting side communication circuit 16 for controlling communication with the controller unit 30 are included. In response to an instruction from the controller unit 30, the light projection control circuit 14 sequentially activates the N light projection circuits 12, so that the light projection element 11 on the first optical axis to the Nth light projection element 11. Light up one after another. Accordingly, the light projecting unit sequentially emits light beams from the first optical axis to the Nth optical axis at a predetermined light projecting timing toward the light receiving unit.

The light projecting unit has an elongate case extended in one direction, and N light projecting elements 11 are arranged in a line along the longitudinal direction at almost equal intervals. Although the space | interval between the adjacent light projection elements 11 is not specifically limited, For example, it is 20 mm.
(Light receiving unit)

  On the other hand, the light receiving unit 20 is also provided with a light receiving circuit 22 for each light receiving element 21, and the light receiving control circuit 24 connected to each light receiving circuit 22 individually controls them. The light reception control circuit 24 includes a light reception data register 25 as a memory for holding the light reception data received by each light reception circuit 22 and a determination circuit 27 for making a determination according to the light reception data held in the light reception data register 25. . An electric signal corresponding to the amount of light received output from the light receiving circuit 22 is amplified by the amplifier circuit of the light receiving control circuit 24, and the output voltage of the amplifier circuit is converted into a digital value by the A / D converter and held in the light receiving data register 25. To do. Further, the light receiving unit 20 also includes a light receiving side communication circuit 26 for communicating with the controller unit 30.

The light receiving unit that constitutes the light receiving unit 20 shown in FIG. 5 includes N light receiving circuits 22 that individually drive light receiving elements 21 such as photodiodes, phototransistors, and PSDs (position detecting photodiodes), and these light receiving circuits. 22 and a light receiving side communication circuit 26 for controlling communication with the controller unit 30. The light receiving control circuit 24 receives the control signal from the controller unit 30 and operates the corresponding light projecting circuit 12 so that the corresponding light receiving element 21 can receive the light beams successively emitted from the light projecting units. In synchronization, the light receiving circuit 22 of the first optical axis to the light receiving circuit 22 of the Nth optical axis are sequentially enabled. As a result, a plurality of optical axes parallel to each other at substantially equal intervals are formed in an area shape, thereby constituting a light curtain.
(Controller part 30)

  The controller unit 30 includes a controller-side communication circuit 31 for performing data communication with the light projecting unit 10 and the light-receiving unit 20, and a controller control circuit 32 that is connected to the controller-side communication circuit 31 and performs various controls. The controller control circuit 32 constitutes control means. The controller control circuit 32 includes a teaching input circuit 33 for performing processing relating to teaching, a work detection sensor input circuit 34 for inputting from the work detection sensor, a memory 35 for holding various set values, and a determination result. Output circuit 36 for generating and outputting a control output signal based on this, setting result for displaying a determination result, setting contents, etc., or displaying a state display monitor 37, a user interface display unit 37, a detection area, etc. Part 38 and the like. The controller unit 30 can use a PLC. An enable switch, a mute sensor, a manual operation signal, or the like can be connected to the PLC. Note that the controller unit 30 is a separate member from the light projecting / receiving unit in the example of FIG. 5, but may be built in the light projecting unit or the light receiving unit.

  A light that is installed at the boundary of a work area including a machine tool, a punching machine, a press machine, a casting machine, an automatic controller, and other devices that can be a danger source, and is connected to the controller unit 30 to be controlled and driven. Configure the curtain. When a part of the body such as the fingertip of the operator enters the work area, this is detected by the multi-optical axis photoelectric sensor, and the controller unit 30 immediately stops the operation of the control target device and / or issues an alarm. Protect operators and workers. Here, a press machine is used as an example of the device to be controlled.

This multi-optical axis photoelectric safety device can output a plurality of safety signals, assign a plurality of areas, and output an independent control output signal for each area. The conventional light curtain has one output per unit, and even if a plurality of units are connected and handled as one unit, the output is only one output. In this configuration, one unit of the light curtain cannot be divided into a plurality of detection areas, and an operation permission signal corresponding to each can not be output. On the other hand, the multi-optical axis photoelectric safety device according to the present embodiment uses one multi-optical axis sensor and independently assigns a plurality of optical axes included therein to a plurality of outputs. The same effect as a safety system using a plurality of multi-optical axis photoelectric safety devices can be obtained. In particular, by making it possible to control a plurality of outputs with a single multi-optical axis photoelectric safety device, it is possible to construct a safety system with ease of design with reduced wiring and low cost. In this way, with respect to a plurality of adjacent devices, the entire area can be protected by one or a plurality of multi-optical axis photoelectric sensors added in series on the surface where the operator and the device face each other. It is possible to group the optical axes to be shielded for each group, and to individually provide a safety output for each group. In the past, one multi-optical axis photoelectric sensor was installed for each device, and a safety output was provided for each. However, according to the present invention, a single multi-optical axis photoelectric sensor can be used. The user can select an area to be protected freely without depending on down and the number of optical axes of the sensor.
(Output circuit 36)

  The output circuit 36 outputs OSSD or FSD as a control output signal. An OSSD (output signal switching device) is an ESPE component connected to a control system of a control target device such as a press machine, and is in an OFF state with the operation of a detector during normal operation of the control target device. is there. Note that ESPE (electro-sensitive protective equipment) means a group of equipment and / or parts that work together for human body protection or object detection, and have at least a detector, a control monitoring equipment, and an OSSD. . An FSD (final switching device) is a component of the safety-related control system of the device to be controlled, and shuts down the MPCE circuit when the OSSD is turned off. Note that the MPCE (machine primary control element) is an element that is electrically driven by directly controlling the normal operation of the device to be controlled, and operates last in time when starting or stopping the operation of the device to be controlled. Is an element. Thus, the control output signal functions as an operation stop signal for stopping the operation of the control target device.

In the example of FIG. 5, the output circuit 36 can output a plurality of control output signals. In order to output a plurality of control output signals, a plurality of output terminals are physically provided so that each can output a control output signal, and one output terminal can output a plurality of control output signals. The structure to perform is also included. As a means for outputting a plurality of control output signals at one output terminal, a known or future developed method such as time division multiplexing can be used as appropriate. Thus, a configuration in which one output terminal can output a plurality of control output signals is also expressed as a plurality of output units in this specification.
(Connection of light emitting / receiving unit)

  The light projecting / receiving unit constituting the multi-optical axis photoelectric sensor has a communication function and can be connected in a connected manner. FIG. 6 shows a state in which the light projecting / receiving unit is connected by the cable 40. The cable 40 is a communication line or a signal line. The light projecting unit or the light receiving unit includes a connector for connecting the cable 40, and a plurality of light projecting / receiving units can be connected in a daisy chain via the cable 40. Connectors are provided at both ends of the light projecting / receiving unit, and may be connected to either side of the two connectors.

  FIG. 7 shows an example in which the controller unit 30 is connected to the light projecting / receiving unit to constitute a safety system. A part of the cable 40 connected in this manner is connected to the controller unit 30. The controller unit 30 can control the connected light emitting / receiving units as if they were one light emitting / receiving unit. Thereby, it is not necessary to wire each light emitting / receiving unit individually, and wiring saving can be realized when a safety system is constructed.

  In addition to the light projecting / receiving unit, other devices such as the emergency stop switch 42, the door switch 44, and the operation indicator 46 can be connected on the line. These devices have a common standard with the communication standard on the line when a communication function is required. Thus, by connecting a plurality of devices on the same line and controlling them by the controller unit 30, it becomes possible to centrally manage and control information on all safety devices by the controller unit 30. Furthermore, by controlling with one line, it becomes possible to prevent mutual interference by shifting the operation timing of light projecting / receiving of a plurality of light projecting / receiving units. The controller unit 30 may be configured to automatically set the interference prevention function for the light curtain on the same bus so as to automatically set such temporal separation.

  RS485 or the like can be used as a communication method on the line. RS485 can use a multiple terminal (multi-drop) scheme that allows multiple terminations. Further, by connecting the lines of the light projecting / receiving unit connected by a cable in a loop shape, it becomes possible to perform more advanced detection and control than disconnection detection or the like. Further, the controller unit 30 is not limited to one unit, and two or more units can be connected on the same line.

  Needless to say, series connection of light curtains is also possible. If a plurality of connection terminals are prepared, an I / O connection that does not perform communication is possible.

The above describes the electrical connection by cables. However, in the present invention, connection typically means electrical connection, but it does not necessarily mean only physical connection, and may be electromagnetic, sound wave, regardless of wireless or wired. Communication using infrared rays, ultraviolet rays, visible rays, and the like is also included. Also, as seen in the transmission and reception of data and energy using electro-optical elements such as OEIC (Optoelectronic Integrated Circuit), transmission and reception of signal data using pressure, sound waves, radio waves, heat, etc. as a medium, including electricity and light. In addition, the state of being “connected” so as to be able to transmit and receive various types of energy is also referred to as the connection according to the present invention, and direct connection or indirect connection is not limited. Furthermore, it is not necessary to be always connected, and the switch circuit or the switching circuit is configured to be connected only when necessary (for example, only when charge, electricity, or current passes) according to the driving state of the drive circuit. Also good. Similarly, the light used as a medium by the photoelectric sensor is used in the meaning including all kinds of light including not only visible light but also infrared rays and ultraviolet rays.
(Granting identification information)

In order for the controller unit 30 to distinguish devices such as a light projecting / receiving unit connected on the same line, identification information is given to each device. The light emitting / receiving unit can be provided with a DIP switch for each unit, for example, and an individual ID can be manually set with the DIP switch. In order to save such manual setting, it is possible to recognize the light projecting / receiving unit to which the controller unit 30 is connected and automatically assign an ID. For example, when the power is turned on, the controller unit 30 transmits ID assigning signals to all the light projecting / receiving units, and assigns ID numbers to the light projecting / receiving units in the order of connection. The ID assigning signal can be transmitted in a packet including an ID number, processing contents, and an operation command.
(Specify detection area)

  The controller unit 30 can specify a plurality of detection areas. The detection area is specified by the setting unit. The setting unit assigns an optical axis belonging to each detection region. As a result, a control output signal is generated for each detection region and output from the output circuit. Therefore, the output circuit includes a plurality of output terminals corresponding to the number of detection areas that can be set.

  For example, consider an arrangement as shown in FIG. In this example, independent work is performed on each of the four work tables A to D arranged on the wall surface. Since each work platform contains a danger source such as a press machine, a pair of light emitting and receiving units are placed so as to surround each work table so that the press machine is stopped by detecting the operator's hand entering each work table. Are arranged so as to surround each press in a U-shape. On the other hand, since A to D are independent operations, it is desirable to stop only the work table that detects the insertion of the hand and to continue the work without stopping the other tables. In such a state, conventionally, since the output of the light projecting / receiving unit is only one system, as shown in FIG. 9, each work table is disposed so as to be surrounded by the light projecting / receiving unit, and the output of each sensor. Independent detection was required. In such an arrangement, it is necessary to place the light projecting / receiving unit in a double boundary between adjacent work tables, and as shown in FIG. 9, the light projecting / receiving units A1, B1 are adjacent to each other at the work table A, B boundary, The light projecting and receiving units B2 and C1 are adjacent to each other at the boundary between the work tables B and C, and the light projecting and receiving units C2 and D1 are adjacent to each other at the boundary between the work tables C and D. As described above, as the number of work tables adjacent to each other increases, the area where the light projecting and receiving units are installed twice increases and a larger space is required. Further, when the number of light emitting / receiving units used increases, the wiring becomes complicated and the cost increases. Furthermore, it is necessary to pay attention to mutual interference in which the operation becomes unstable due to the influence of adjacent light emitting / receiving units.

  On the other hand, as shown in FIG. 8, the multi-optical axis photoelectric sensor according to the present embodiment arranges only one row of light projecting / receiving units in adjacent regions. In the example of FIG. 8, the light projecting / receiving units E1 to E9 are arranged, only the light projecting / receiving unit E3 is provided at the boundary between the work tables A and B, and only the light projecting / receiving unit E5 is provided between the work tables B and C. Only the light projecting / receiving unit E7 is arranged between D. Then, the light projecting / receiving unit E1, E2, E3 is designated as the detection area A. Further, the light projecting / receiving unit E3, E4, E5 is designated as the detection area B. Similarly, the light projecting / receiving units E5, E6, E7 are designated as the detection area C, and the light projecting / receiving units E7, E8, E9 are designated as the detection area D. As a result, the photoelectric sensors can be shared without arranging a plurality of photoelectric sensors in the same site as shown in FIG. 9, and low cost and space saving can be realized. In particular, by arranging one light projecting / receiving unit at the boundary between adjacent regions and sharing it with the adjacent region, the number of the light projecting / receiving units to be used can be reduced and the same effect can be obtained. In addition, by reducing the number of light emitting / receiving units, a neat arrangement is achieved, and space saving, wiring saving, and cost reduction can be realized.

  Furthermore, the control output signal can be output individually for each detection region. For example, even if light shielding is detected in the detection area A and a control output signal is output, it only stops the press included in the detection area A, and does not affect the detection areas B to D. As a result, it is possible to achieve both safety and efficiency without stopping only the part that needs to ensure safety and stopping the entire system.

  In the above-described configuration, when light shielding is detected by the light projecting / receiving unit arranged in the adjacent area, it goes without saying that the press machine in the detection area assigned to the light projecting / receiving unit is stopped. Absent. For example, in the example of FIG. 8, when the light projecting / receiving unit E3 detects light shielding, the detection areas A and B are stopped, but this is not different from the configuration of FIG. 9 and the result.

  In the above example, the control signals are generated independently in the detection areas A to D. However, in a related area or the like, these can be designated as a combined detection area. For example, when the detection areas B and C are related and it is necessary to stop both of the presses included in the detection areas B and C at the time of stopping, the light projecting / receiving units E3, E4, E6, When E7 is designated and one of the optical axes is shielded, both the presses included in the detection areas B and C can be stopped.

  Furthermore, in the above example, the detection area is specified in units of light emitting / receiving units, but it is also possible to specify the detection area in units of optical axes included in the light emitting / receiving units. For example, as FIG. 10, consider an example in which a light projecting / receiving unit E10 having a length corresponding to this is arranged instead of the light projecting / receiving unit E2, E4, E6, E8 under the same conditions as in FIG. The detection area A includes the light projecting / receiving units E1, E3 and the optical axis e1 of E10, the detection area B includes the light emitting / receiving unit E3, the optical axes e2 of E5 and E10, and the detection area C includes the light projecting / receiving units E5, E7 and E10. The optical axis e3 and the detection area D can be designated like the optical axis e4 of the light projecting / receiving units E7, E9 and E10. Thereby, one light projecting / receiving unit can be designated like a plurality of light projecting / receiving units. Conversely, as shown in FIG. 8, a plurality of light projecting / receiving units can be grouped together as a single light projecting / receiving unit, or specification across a plurality of light projecting / receiving units can be performed. In the example of FIG. 11, instead of the light projecting / receiving unit E10 of FIG. 10, three light projecting / receiving units E11, E12, E13 are combined. Similarly to FIG. 10, in addition to the light projecting / receiving units E1 and E3, the detection area A is constituted by a part of the optical axis e1 of the light projecting / receiving unit E11, and in addition to the light projecting / receiving units E3 and E5, the light projecting / receiving unit E11. It is possible to specify a detection area across a plurality of light projecting / receiving units, for example, a detection area B is constituted by a part of the optical axis e2 ′ and a part of the light axis e2 ″ of the light projecting / receiving unit E12.

  FIG. 12 shows another example in which a partially overlapping area is designated as a detection area. As shown in this figure, consider an example in which two long light projecting / receiving units E14, E15 are arranged vertically and a light curtain is arranged in front of the presses A, B. When designating the detection area A1 for the press A and the detection area B1 for the press B with the optical axis of the light projecting / receiving unit, a part of the optical axes is set so that the detection areas A1 and B1 overlap at the ends. Can be shared. In this way, it is possible to divide like a plurality of light projecting / receiving units of one light projecting / receiving unit and to share a part of the optical axis. This makes it possible to specify a more detailed detection area.

  The plurality of detection areas are preferably each provided with an operation indicator. Thus, since the user can easily visually recognize the output state of each detection area, even if a plurality of detection areas are designated, confirmation can be easily performed. The operation indicator lamp is composed of, for example, red and green LEDs. When normal, the green LED is turned on and the red LED is turned off, and when abnormal, the green LED is turned off and the red LED is turned on. The operation indicator lamp may be externally attached, or any one of the sensor units may be provided with an output display unit such as an LED. In the latter case, at least one of the sensor units belonging to each detection region includes a sensor unit provided with an output display unit, and this output display unit is caused to function. Further, operation indicator lamps may be provided in all the sensor units, and the output display unit may function in all the sensor units belonging to the detection area group. Further, the output unit of the sensor unit and the operation indicator lamp may be combined.

In this way, by setting one optical axis to belong to a plurality of groups, it is sufficient to arrange only one light projecting / receiving unit, which conventionally has to be disposed twice in the boundary region. Thus, wiring saving and cost reduction are realized.
(Setting method)

  The association between the light projecting unit and the light receiving unit, that is, the designation of the light projecting / receiving unit constituting the pair can be performed from the external input means. Here, as an external input means, a setting program installed in a general-purpose device such as a computer is used, and the computer and the controller unit are connected by some method to exchange data.

For example, the controller unit 30 and the computer exchange data using general-purpose communication means such as USB or a medium such as a memory card. From the control circuit of the controller unit 30, the configuration data such as the number of optical axes / number of units / minimum detection body of the light projecting / receiving unit constituting the light curtain connected thereto is taken into the computer side, and the basic information is set. Then, set the setting items specifically. For example, the user turns off the outputs 1-A and 1-B when any part from the first optical axis to the 16th optical axis of the first unit is blocked by the setting program on the computer. When somewhere up to 64 optical axes is shielded, the outputs 2-A and 2-B are turned off. A total of two optical axes from the 32nd optical axis of the first unit to the final optical axis of the second unit are shielded. Then, settings such as turning off the outputs 3-A and 3-B are performed. In the case of a light curtain, it is preferable to provide two output lines for one system control output in preparation for failure of the output circuit. After the setting is completed, the set content is transmitted from the computer side to the control circuit of the controller unit 30, and the setting content of the control circuit of the controller unit 30 is updated. The control circuit of the controller unit 30 naturally includes light incident / light shielding data for each optical axis, so that signal processing is performed based on the rules set as described above, and a predetermined control output is output. Let
However, it is also possible to provide such a setting function in the controller unit itself so that the user operates the controller unit to perform the setting. The controller control circuit 32 of the controller unit 30 includes a setting unit 38. The setting unit 38 applies an invalidation function such as floating blanking to any area of the light curtain via a user interface, and to which area a normal operation is performed. Setting information on whether to apply the safety function is supplied to the light receiving unit 20. Examples of the user interface of the setting unit 38 include switch input, direct input of an invalidation function application area using a numeric keypad, and teaching input. The user can arbitrarily set the invalidation function application area using this user interface.

  The detection area can also be set by the teaching method. Teaching is set by actually passing the work and memorizing the light incident / light shielding state at that time. When execution of teaching is input from the teaching input circuit 33 of the controller control circuit 32, the teaching mode is set and the detection area is set by the teaching method. The set contents are held in the memory 35 which is a nonvolatile memory. When teaching, the grouping of detection areas is also set at the same time. For example, an area shielded during a predetermined operation is designated as group 1 of detection areas. After the teaching is completed, the multi-optical axis photoelectric safety device is manually or automatically switched to the normal operation mode.

  Furthermore, the setting by a handy console is also possible. For each optical axis, a group to which the detection area belongs is set, and a safety signal is set to be output on the multi-optical axis photoelectric safety device side for each group.

  In the above setting, the output for each optical axis of the multi-optical axis photoelectric sensor is managed on the safety control device side. Specifically, it is managed as an I / O of the safety PLC in the same manner as the internal relay of the programmable controller. By forming an OR circuit by a program in which the user sets the input for each optical axis, grouping of the optical axes is realized, and a signal that one of the optical axes in the group is shielded is It can be reflected in the associated safety output. The associated information is stored in the memory of the controller unit 30. This safety output is used for the purpose of shutting off the power source of the press machine, and is used not only for directly shutting off the power source of the press machine but also for opening and closing devices such as contactors through the shut-off.

In addition, it is desirable to manage the setting contents so that the setting cannot be easily changed because the setting can be easily changed, which may cause an unexpected decrease in safety and may cause an accident. Specifically, if the machine manufacturer makes settings at the time of shipment from the factory and then does not allow the setting change, or the user installs / sets under the supervision of an administrator with sufficient knowledge, Follow the instructions of the administrator. As an example for realizing this, a dedicated memory card that cannot be written by a general-purpose tool is used. Alternatively, it is possible to appropriately use a method such as management using a password or making writing possible only when the H / W key is connected to a computer.
Example 1

  Further, the multi-optical axis photoelectric safety device has a function capable of switching a safety function in accordance with a detection state of each optical axis. Specifically, it has a disabling function that disables the safety function so that it does not work even if a specific workpiece is detected. By switching ON / OFF the disabling function, a safety function is provided for the necessary work. Can be turned off for efficient system operation. Hereinafter, the multi-optical axis photoelectric safety device according to the first embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 13 shows an example in which a light curtain is arranged on a path along which the workpiece W is transported to the press machine. In this example, a light projecting / receiving unit 48 in which 13 optical axes of 1Ax to 13Ax are arranged on a straight line is used and arranged in the horizontal direction so that the longitudinal direction thereof coincides with the traveling direction of the workpiece W. A detection area is formed between the units, and the workpiece W enters by a conveyor or the like during this period. Naturally, the entry of the workpiece W is a normal operation, and even if the light projecting / receiving unit 48 detects the workpiece W, it is not desired to stop the system. For this reason, it is necessary to turn on a disabling function for temporarily disabling the safety function of the light projecting / receiving unit 48 so that the system does not stop when the work W enters.

  In the conventional system, when the workpiece W enters from the left in FIG. 13 and enters the light shielding state even with one optical axis, the light shielding state is immediately reflected in the control output, and the OSSD or FSD output of the output circuit is turned off. Will be stopped, which is not preferable.

  In contrast, in the multi-optical axis photoelectric safety device according to the present embodiment, the normal workpiece shape detection area is designated from the detection area, and the safety function is invalidated based on the detection result in the normal workpiece shape detection area. Configure to switch functions. Specifically, the first to fifth optical axes (1Ax to 5Ax) of the optical axis of the light projecting / receiving unit 48 are designated as the normal workpiece shape detection area. If this area is shielded in a sequence that is predicted in advance, it is determined that a normal workpiece W has entered as specified, and conversely, if it is blocked in an unexpected sequence, an error other than that specified is detected. It is determined that an intrusive work such as a human hand has been invaded.

  This process will be described in more detail based on the timing chart of FIG. By normal entry of the workpiece W, the light projecting / receiving unit 48 is sequentially shielded from the first optical axis (1Ax) to the second, third and fourth optical axes (2Ax to 4Ax). For example, at the timing a, the 2, 3, and 4 optical axes are shielded. From this light shielding state, it can be determined that the size of the workpiece W is a size for shielding the three optical axes.

  At the next timing b, the 3, 4, and 5 optical axes (3Ax to 5Ax) are in a light shielding state, and the workpiece W having a size that can shield the three optical axes is moved to a dangerous area where the press machine exists. Can be determined.

  The object of the present embodiment is to transfer a specified work to the work area (dangerous area) of the apparatus without turning off the control output (OSSD or FSD) of the light curtain, and other work such as a human body, etc. In case of intrusion, the system is promptly reflected in the control output and the system is stopped. In the present embodiment, 1 to 5 optical axes (1Ax to 5Ax) are designated as normal workpiece shape detection areas, but 6 to 13 optical axes (6Ax to 13Ax) are set as abnormality detection areas. That is, during normal operation, the control output is immediately turned off when even one optical axis is blocked, but the workpiece W determined as the designated workpiece in the normal workpiece shape detection area as described above is the normal workpiece shape. When moving sequentially from the detection area side, it is possible to pass the work W while the control output is in the OK state without reflecting the light shielding state by the work W in the control output.

  Specifically, as described above, at the timing b, information indicating that the designated workpiece W is moving toward the dangerous area can be determined, and next, the sixth optical axis (6Ax) is shielded. It can be easily predicted to be in a state. That is, the controller control circuit, which is one form of the control means, determines that the designated work W is in the light-shielded state at the next timing from the light-shielded state at the timing b, and the sixth optical axis is partially set in advance. Set to a mute state.

  Next, at the timing c, it is obvious that the fourth, fifth, and sixth optical axes are in a light shielding state, and the seventh optical axis is in a light shielding state next. That is, the controller unit sets the 6th and 7th optical axes (6Ax to 7Ax) to the mute state so that the 6th and 7th optical axes are not reflected on the control output by the work W.

  Similarly, at the timings d and e, the 8th and 9th optical axes (8Ax to 9Ax) are sequentially set to the muting state. However, at the timing f, since the work W has finished passing and has changed to the light incident state again, it is determined that this optical axis has passed the work W, and the muting setting is cancelled. That is, when the sixth optical axis (6Ax) is again blocked by a human body or the like, the control output is turned off. The above operation is repeated until the workpiece W completes passing through the abnormality detection area.

  By supplying a light curtain system that operates in this way, it is possible to eliminate the need for a muting device such as a conventional muting sensor for detecting a workpiece and starting mute. Further, since no muting device is required, wiring saving can be realized. Furthermore, since the size of the workpiece is strictly determined, it is possible to avoid erroneous determination between the specified workpiece and other workpieces. It is also possible to detect the length of the workpiece. For example, when a normal workpiece shape detection area is set by teaching, it is possible to measure and display how many workpieces are on the optical axis. In addition, since the optical axis is arranged along the work entry direction by installing the light projecting part and the light receiving part so that the longitudinal direction is parallel to the work entry direction, the length of the work in the longitudinal direction is detected. Can be done reliably.

  Furthermore, the size of the workpiece can be determined strictly, the muting function can be validated only in the area where the workpiece exists, and the normal safety function can be maintained in other areas. In other words, since the operation to turn off the control output is continued when some foreign matter is detected, even if the workpiece and the human body enter at the same time, the human body can be detected reliably, and the control output can be turned off, thereby preventing danger. .

  As described above, according to the first embodiment, the invalidation function such as the mute function can be reliably operated with a simple configuration, and the invalidation can be performed only with the minimum necessary portion, thereby maintaining high safety. In other words, in the past, when a light curtain was installed at the entrance of the hazardous area and only the workpiece was passed through the hazardous area using the mute function, two workpiece detection sensors (muting sensors) were provided. Or four were necessary. On the other hand, in Example 1, the same function can be provided only by the light curtain without using a muting device. From another point of view, a plurality of sensor units can be used, a part can be used as a safety sensor, and a part can be used in pairs as a shape discrimination sensor for the sensor unit. It is also possible to detect that a workpiece having a different shape has been input.

In the conventional method, the workpiece detection sensor needs to be properly arranged according to the size of the workpiece. If the workpiece size changes, the position of the workpiece detection sensor needs to be readjusted. is there. In contrast, in this embodiment, the size of the work can be recognized by the control circuit side by the number of light-shielding optical axes of the light curtain, and by providing a plurality of memories for storing the size of the work at the time of initial adjustment, For example, the size of the workpiece can be changed from the controller side. In addition, it is possible to mute only the necessary optical axis groups and set the other optical axis groups to the normal state, and achieve both safety and efficiency according to the state of the press machine to be controlled. Operation becomes possible.
(Example 2)

  In the first embodiment described above, the case where the light projecting / receiving unit 48 is horizontally placed so as to be along the traveling direction of the workpiece has been described. Of course, the light projecting / receiving unit can be arranged so as to be orthogonal to the advancing direction of the workpiece, that is, vertically. Hereinafter, the multi-optical axis photoelectric safety device according to the second embodiment of the present invention will be described with reference to FIGS. In the example of FIG. 15, the workpiece W2 conveyed by the conveyor 3 toward the press P has an inclined surface, and the area intersecting with the light curtain arranged in the vertical direction changes according to the progress of the workpiece W2. Therefore, the invalidation function can be exhibited by correctly detecting the progress of the workpiece W2 on the basis of the changing area, that is, the incident / shielded state.

  As shown in FIG. 15, a light curtain 49 having 12 optical axes of 1 Ax to 12 Ax is installed vertically at the entrance of the workpiece W2. In addition, sensors A1, A2, B1, and B2 are disposed as work detection sensors 50 on both sides of the path along the approach path of the work W2. The workpiece detection sensor 50 also forms an optical axis similar to that of the light curtain 49, and outputs a workpiece detection signal to the controller unit based on the incident / light-shielded state.

  A block diagram of this multi-optical axis photoelectric safety device is shown in FIG. As shown in this figure, the workpiece detection signal of the workpiece detection sensor 50 is input to the workpiece detection sensor input circuit 34 of the controller unit 30. The light projecting / receiving unit constituting the light curtain 49 is connected to the controller side communication circuit 31 of the controller unit 30. Further, the output circuit 36 of the controller unit 30 is connected to a STOP input for stopping the apparatus of the press machine P. When the output circuit of the controller unit 30 issues a control output signal based on the light incident / light shielding state of the light projecting / receiving unit, the STOP input is activated and the press P is stopped.

  In such a case, conventionally, muting for temporarily disabling the safety function of the light curtain is performed based on the light incident / light shielding information of the workpiece detection sensors A1, A2, B1, and B2 provided in the vicinity of the light curtain. It is common. In this case, it is necessary to invalidate all the detection areas or invalidate all the optical axes in a range corresponding to the maximum size of the workpiece so that at least the workpiece can pass without being detected. In either case, there is a problem that when a foreign object such as a human hand enters at the same time as the work in the muting state, it cannot be detected. In particular, even in the latter case, since the optical axis in a range corresponding to the maximum size of the workpiece is invalidated, a region (dead space) that cannot be detected depending on the shape of the workpiece may be generated.

  Alternatively, a method may be considered in which not all areas in the area protected by the light curtain are invalidated, but the area in which the safety function is invalidated is changed stepwise by an external signal. For example, as shown in FIG. 17, a control device such as a PLC is arranged as a sequencer 52 that performs higher-level control, and a switching signal from the PLC is received by an area switching circuit 54, and the muting area is varied accordingly. Obviously, in this method, it is necessary to add a control device separately, and there is a problem that the control and configuration become complicated and costly.

  On the other hand, in the multi-optical axis photoelectric safety device according to the second embodiment, the safety function is not invalidated over the entire detection area during the muting operation, or the protection area is sequentially switched by an external signal such as PLC. It is possible to change the protection area automatically according to the intrusion of the workpiece by a predetermined sequence. Specifically, when the workpiece W2 enters, the workpiece detection sensor A1 and then A2 are in a light-shielded state, and the workpiece detection signal that is the output of these sensors is inverted. When the conventional muting function is used, the muting state is entered when the light shielding state occurs (timing 4 in the timing chart of FIG. 18), and the safety function by the light curtain is disabled over the entire detection area. On the other hand, in the case of the present embodiment, it is not invalidated over the entire protection area of the light curtain, but at this timing, the portion where the light curtain is first shielded with the intrusion of the work W2 (in this embodiment, 1, A partial muting state with only the second optical axis) is set (corresponding to the shaded portions of 1Ax and 2Ax at timings 4 and 5 in the timing chart of FIG. 18).

  Next, the workpiece W2 enters and the first and second optical axes of the light curtain are in a light-shielding state (timing 6 in the timing chart). In the operation so far, the first and second optical axes are set to the partial muting state, so that the output remains on even when the first and second optical axes are in the light shielding state. In addition, since the shape of the workpiece W2 is known in advance because the first and second optical axes are shielded, in the present embodiment, it can be easily predicted that the third optical axis will be shielded at the next timing. . Accordingly, the third optical axis is set to the muting state at the timing when the first and second optical axes are shielded (the state of timings 7 and 8 in the timing chart). Similarly, when the third optical axis is in a light-shielded state, the fourth optical axis is muted, and when the fourth optical axis is in a light-shielded state, the fifth optical axis is muted. In this way, settings are made sequentially. Thus, when the muting state is set up to the 11th optical axis and the light shielding state is reached up to the 11th optical axis, the light shielding state by the work W2 is interrupted at the next timing from the shape of the work W2, and 3 to 11 lights It is expected to be in the light incident state up to the axis. When the 3 to 11 optical axes are actually incident, the muting state of the 3 to 11 optical axes is temporarily canceled based on a preset sequence. As a result, when the light is blocked in the range of 3 to 11 optical axes, it is expected that a person is present in this portion. Therefore, the light curtain turns off the control output, and the device of the press machine P is turned off. It can be stopped (timing 27 and 28 in the timing chart). Considering the shape of the workpiece W2, it is expected that the 3 to 11 optical axes will again be in a light-shielded state. Therefore, after a certain period of time has passed, it is necessary to put the 3 to 11 optical axes in the muting state. This timing is muting after a preset time elapses, considering the shape of the work W2 and the speed of the conveyor line from the time when the 3-11 optical axis enters the light incident state at the timing of 25 → 26 in the timing chart. The state is set again (timing 29 in the timing chart).

  Thereafter, when the eleventh optical axis enters the light incident state in accordance with the shape of the workpiece W2 set in advance, the muting state of the eleventh optical axis is canceled (timing 32 in the timing chart), and thereafter, the muting is sequentially performed in the same manner. In the same way as in the conventional example, the release state of the muting state of the 1 and 2 optical axes is finally released when the workpiece detection sensors B1 and B2 are in the light incident state after all of the workpieces W2 have passed. Release with.

  With the above method, when a light curtain with a muting function is installed at the work entrance, if a person enters the work at the same time as the muting state, the person cannot be detected. Can be resolved. Further, compared to a method of changing the muting area according to an external switching signal such as a PLC, it is possible to realize a minimum muting state in accordance with the work shape by a system having only a light curtain. For this reason, as shown in FIG. 16, it can simplify compared with the conventional structure shown in FIG.

  Similarly, in the present embodiment, the description has been given by limiting the function to the muting function. However, the setting may be performed by combining not only the muting function but also the floating blanking function and the fixed blanking function. For example, the third optical axis at timing 4 of the timing chart, the twelfth optical axis at timings 24, 25, and 26 may be shielded from light due to flapping of the workpiece. In that case, not only the muting function, but at timing 4 in the timing chart, for example, flapping of the work occurs by setting the 1 and 2 optical axes to the muting function and the 3 and 4 optical axes to the floating blanking function. Even in this case, there are merits such as stabilization of the operation under actual use conditions such as the control output is not immediately turned off.

  Setting means for setting the muting function, the floating blanking function, the fixed blanking function, and the like can be performed by a teaching method in addition to using an external input means such as a computer as described above. That is, after switching to the teaching mode by the teaching input circuit 33 of the controller control circuit 32, the workpiece is actually intruded between the optical axes of the light curtain, and the change in the incident / light-shielding state at that time is stored and registered as a pattern. Can be made. Further, when a work different from the registered pattern intrudes, it can be detected that a work different from the registered work has entered. The setting is made in units of one optical axis or in units of a plurality of optical axes according to the relationship between the work penetration speed and the response speed of the multi-optical axis photoelectric sensor. Furthermore, the total length, shape, etc. of the workpiece at this time can be detected from the light-shielded state of the optical axis. It is also possible to register a plurality of workpieces in advance and distinguish them. Furthermore, in this method, since the change in the incident / light-shielding state can be registered not by time but by a pattern, it is possible to appropriately cope with a line stop or speed change. In addition, since the shape of the workpiece is determined in a region where the workpiece first shields the optical axis of the light curtain, the determination process at an early stage can be started, and an advantage that a rapid process is possible is also obtained.

  The multi-optical axis photoelectric safety device and the control method thereof according to the present invention can be suitably used as a photoelectric sensor, a photoelectric proximity switch, or the like constituting a light curtain. Further, the present invention can be applied not only to a transmissive light curtain but also to a reflector type in which a projector and a light receiver are integrated.

It is explanatory drawing explaining the outline | summary of a floating blanking function. It is explanatory drawing explaining the outline | summary of a fixed blanking function. It is explanatory drawing explaining the outline | summary of a muting function. It is a top view which shows a mode that a workpiece | work enters a protection area with the conventional recognition method. 1 is a block diagram showing a multi-optical axis photoelectric safety device according to an embodiment of the present invention. It is explanatory drawing which shows the state which connects a light projection / reception unit with a cable. It is a block diagram which shows the example which connects a controller part with a light projection / reception unit, and comprises a safety system. It is a schematic plan view which shows the example which each sets a detection area | region based on embodiment of this invention surrounding each press machine of AD to U shape. It is a schematic top view which shows the prior art example which surrounds each press of A to D in a U shape, and sets a detection area individually. It is a schematic plan view which shows the example which has arrange | positioned the long light projection / reception unit on the same conditions as FIG. It is a schematic plan view which shows the example which has arrange | positioned three light projection / reception units on the same conditions as FIG. FIG. 10 is a schematic plan view showing an example in which detection regions are individually set based on the embodiment of the present invention under the same conditions as in FIG. 9. It is a perspective view which shows the example which detects a workpiece | work with the multi-optical axis photoelectric safety apparatus which concerns on Example 1 of this invention. It is a timing chart which shows the state which detects the workpiece | work of FIG. 13 with a multi-optical axis photoelectric safety device. It is a perspective view which shows the example which detects a workpiece | work with the multi-optical axis photoelectric safety apparatus which concerns on Example 2 of this invention. It is a block diagram which shows the multi-optical axis photoelectric safety device which concerns on Example 1 of this invention. It is a block diagram which shows the conventional multi-optical axis photoelectric safety device. It is a timing chart which shows the state which detects the workpiece | work of FIG. 15 with a multi-optical axis photoelectric safety device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Multi-optical axis photoelectric safety device 1 ... Light curtain 2 ... Wire 3 ... Conveyor 4 ... Muting sensor 5 ... Optical circuit breaker 6 ... Optical grid 10 ... Light projection part 11 ... Light projection element 12 ... Light projection circuit 14 Light emitting control circuit 16 Light emitting side communication circuit 20 Light receiving unit 21 Light receiving element 22 Light receiving circuit 24 Light receiving control circuit 25 Light reception data register 26 Light receiving side communication circuit 27 Determination circuit 30 Controller unit 31 Controller side communication circuit 32 ... Controller control circuit 33 ... Teaching input circuit 34 ... Work detection sensor input circuit 35 ... Memory 36 ... Output circuit 37 ... Display unit 38 ... Setting unit 40 ... Cable 42 ... Emergency stop switch 44 ... Door switch 46 ... Operation indicator 48 ... Light emitting / receiving unit 49 ... Light curtain 50 ... Work detection sensor 52 ... Sequencer 4 ... area switching circuit W, W2 ... work P ... press

Claims (9)

A light projecting unit having a plurality of light projecting elements for projecting light;
A light receiving unit that is arranged to face the light projecting unit and has a plurality of light receiving elements for receiving light projected from the light projecting unit;
A controller capable of forming a detection region with a plurality of optical axes configured between the light projecting unit and the light receiving unit, generating a control output signal based on the light incident / shielding state of the optical axis, and outputting the control output signal to the outside And
A multi-optical axis photoelectric safety device comprising:
The multi-optical axis photoelectric safety device includes an invalidation function for temporarily invalidating a safety function for outputting a control output signal,
The multi-optical axis photoelectric safety device further includes:
Setting means for associating a light incident / shielding state of one or more first optical axes with the invalidation function applied to one or more second optical axes;
Applying the invalidation function associated with the second optical axis by the setting means based on the incident / shielded state of the first optical axis, and the incident / shielded state of each optical axis and Control means for generating a control output signal based on the invalidation function;
An output means for outputting the control signal;
A multi-optical axis photoelectric safety device comprising: The multi-optical axis photoelectric safety device according to claim 1,
The multi-optical axis photoelectric safety device, wherein the first optical axis constitutes a normal workpiece shape detection area, and the second optical axis constitutes an abnormality detection area. The multi-optical axis photoelectric safety device according to claim 2,
A multi-optical axis photoelectric system in which the setting means is configured to be able to use a teaching method in order to set a light incident / light shielding pattern on the first optical axis constituting the normal workpiece shape detection area. Safety device. The multi-optical axis photoelectric safety device according to any one of claims 1 to 3,
A multi-optical axis photoelectric safety device having at least one of a fixed blanking function, a floating blanking function, and a muting function as the invalidation function. A light projecting unit having a plurality of light projecting elements for projecting light;
A light receiving unit that is arranged to face the light projecting unit and has a plurality of light receiving elements for receiving light projected from the light projecting unit;
A controller capable of forming a detection region with a plurality of optical axes configured between the light projecting unit and the light receiving unit, generating a control output signal based on the light incident / shielding state of the optical axis, and outputting the control output signal to the outside And
A multi-optical axis photoelectric safety device comprising:
The multi-optical axis photoelectric safety device includes an invalidation function for temporarily invalidating a safety function for outputting a control output signal,
The multi-optical axis photoelectric safety device further includes:
A workpiece detection sensor for detecting intrusion of the workpiece along the workpiece traveling direction;
A workpiece detection sensor input circuit for inputting a workpiece detection signal from the workpiece detection sensor;
Setting means for setting in advance to apply the invalidation function to a predetermined optical axis;
Control means for changing the optical axis to which the invalidation function set by the setting means is applied based on the workpiece detection signal input by the workpiece detection sensor input circuit;
An output means for outputting the control signal;
A multi-optical axis photoelectric safety device comprising: The multi-optical axis photoelectric safety device according to claim 5,
The invalidation function includes at least one of a fixed blanking function, a floating blanking function, and a muting function,
The control means uses the workpiece detection sensor input circuit to select one of an optical axis for enabling the muting state, an optical axis for enabling the floating blanking function, or an optical axis for enabling the fixed blanking function. A multi-optical axis photoelectric safety device having a function of changing based on an input workpiece detection signal or a signal of an optical axis whose light incident / shielding state has changed. The multi-optical axis photoelectric safety device according to claim 6,
Based on the workpiece detection signal input by the workpiece detection sensor input circuit or the signal of the optical axis whose light incident / light-shielding state has changed, the control means, after a lapse of a certain time, according to the timing of change of the light incident / light-shielding information of each optical axis A multi-optical axis comprising a function of changing any one of an optical axis for enabling a muting state, an optical axis for enabling a floating blanking function, and an optical axis for enabling a fixed blanking function. Photoelectric safety device. The multi-optical axis photoelectric safety device according to any one of claims 1 to 7, further comprising:
A plurality of the detection areas can be specified, and a plurality of the control output signals are generated for each detection area, and a detection area setting unit for assigning an optical axis belonging to each detection area is provided,
A multi-optical axis photoelectric safety characterized in that a control output signal is generated in each detection region based on the incident / light-shielded state of the optical axis, and the output means can output each control output signal. apparatus. A control method for a multi-optical axis photoelectric safety device,
A light projecting unit having a plurality of light projecting elements for projecting light, and a plurality of light receiving elements arranged to face the light projecting unit and receiving light projected from the light projecting unit Forming a detection region in which a plurality of optical axes are arranged substantially in parallel with the light receiving unit, and arranging the detection region so as to intersect or coincide with the entry direction of the workpiece;
Floating blanking in which the blanking area in the detection area fluctuates according to the position of the moving workpiece with respect to the previously blocked optical axis when the work is loaded so that the optical axis in the detection area is sequentially shielded A process of setting functions;
Based on the incident / blocking information of the optical axis for which the floating blanking function is set, the floating blanking function is set for the next optical axis adjacent to the optical axis, and the first optical axis is set. Setting the muting or fixed blanking function,
When the work passes, the muting or fixed blanking function settings are released sequentially from the incident light axis based on the incident / light-blocking information of the previously incident light axis, and the safety function is operating. The process of returning to
A control method for a multi-optical axis photoelectric safety device, comprising:

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