JP2006112982A - Multi-axis photoelectric sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine connection failure or disconnection of a cable for interconnecting projectors of a master unit and a slave unit and/or a cable for interconnecting light receivers, when a plurality of multi-axis photoelectric sensors are interconnected in series and operated as one light curtain. <P>SOLUTION: When a connector cover 12 is mounted on a connector cover 12 for covering the opening 5A for connecting the slave unit of the multi-axis photoelectric sensor 1, and when the connector cover 12 is not mounted, the logical value of a terminal 13e for recognizing the series connection is varied. The logical value is set to indicate a normal state when the connector cover 12 is mounted, and to indicate the normal state also when the cable 7 is connected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multi-optical axis photoelectric sensor.

  A multi-optical axis photoelectric sensor is frequently used as a security device for detecting that an object (for example, an operator's hand or finger) has entered the danger area. The multi-optical axis photoelectric sensor is configured by a set of a light projector including a plurality of light projecting elements and a light receiver including a plurality of light receiving elements corresponding thereto. As described in Patent Document 1, the multi-optical axis photoelectric sensor has a timing circuit and a drive circuit provided for each light projecting element or light receiving element, and sequentially operates the light projecting elements one by one. The light beam is emitted, and the corresponding light receiving element is activated in synchronization with the light beam. After confirming that the light receiving element has received the light beam, the next light projection and reception is performed at a predetermined timing. When the light receiving element does not receive the light beam, a light shielding signal is output from the multi-optical axis photoelectric sensor. In other words, the multi-optical axis photoelectric sensor is also called a light curtain. If any of the many optical axes that make up this light curtain is shielded, it outputs a light shielding signal and issues an alarm or is installed in a hazardous area. The operation of the press machine and the working robot can be stopped.

When a set of multi-optical axis photoelectric sensors is insufficient to partition a dangerous area, it is common to connect a plurality of sets of multi-optical axis photoelectric sensors in series and use them as one light curtain. Recent multi-optical axis photoelectric sensors include a control circuit (gate array or CPU) for each set of light emitters / receivers as described in Patent Documents 1 to 3, and the multi-optical axis photoelectric sensors are connected to a dedicated cable. Each multi-optical axis photoelectric sensor is designed to automatically recognize a relative connection relationship and operate as a parent device or a child device. That is, the recent multi-optical axis photoelectric sensor is not designed exclusively for the master unit or the slave unit, but is designed to operate as the master unit or the slave unit depending on the usage mode. When optical axis photoelectric sensors are connected in series and used as one light curtain, one multi-optical axis photoelectric sensor operates as a master unit and outputs a light shielding signal to the outside, and the other multi-optical axis photoelectric sensor The sensor operates as a slave unit to supply a light shielding signal to the master unit, and the master unit that has received the signal outputs the light shield signal to the outside.
Japanese Patent Laid-Open No. 11-345548 WO98 / 0150516 (Japanese Patent No. 3465263) JP 2002-303684 A

  For example, when a light curtain is made by connecting two sets of multi-optical axis photoelectric sensors in series, the connection between the two projectors is normal, but the cable connecting the two receivers is disconnected for some reason. In such a case, only the light receiver of the parent device operates in a state where the light receiver of the child device does not operate. On the other hand, the two projectors operate normally, and light beams are sequentially emitted from the many projector elements included in the two projectors. In such a case, since the slave unit on the receiver side is not operating, even if a light beam is emitted from the projector of the slave unit, the receiver of the slave unit does not receive light. The photoelectric sensor outputs a light shielding signal, which makes it possible to know that some abnormality has occurred in the light curtain composed of two sets of multi-optical axis photoelectric sensors. The same applies to the case opposite to the above case, that is, when the connection between the light receivers is normal, but the cable connecting the projectors is disconnected for some reason.

  As another method, based on information on the number of optical axes output from the light projecting / light receiving element switching circuit (optical axis switching circuit) when the power is turned on or during operation, Obtain the number of axes and the number of optical axes of the main unit / slave unit of the receiver, determine whether the number of optical axes of the corresponding projector / receiver is the same, and if it does not match, recognize an error and lock out By configuring so as to be in a state (output of a light shielding signal due to an error), it is possible to know the disconnection of one of the connection cables.

  However, if both the projectors and receivers that make up the two sets of multi-optical axis photoelectric sensors are defective in connection for some reason, for example, maintenance of a press machine installed in a construction or danger area, for example, Therefore, if you forget to reconnect the cables that connect the projectors and the cables that connect the receivers, and forget to reconnect them after this operation is completed, The sensor recognizes itself as being installed without a slave unit and operates only with the master unit even though the slave unit does not operate at all.

  Therefore, although it is originally a light curtain composed of two sets of multi-optical axis photoelectric sensors, it is left without knowing the fact that the part of the slave unit is completely invalidated, There is a possibility that it will continue to be used under the recognition that it is a light curtain composed of two sets of multi-optical axis photoelectric sensors.

  Here, the relationship between the master unit and the slave unit is relative, and when one light curtain is made with two sets of multi-optical axis photoelectric sensors, the multi-optical axis photoelectric sensor that outputs a light shielding signal to the outside is A multi-optical axis photoelectric sensor connected to the parent device is a child device. When one light curtain is made with three sets of multi-optical axis photoelectric sensors, one multi-optical axis photoelectric sensor that outputs a light shielding signal to the outside is related to other multi-optical axis photoelectric sensors connected thereto. The other multi-optical axis photoelectric sensor becomes the parent device, and the light-shielding signal is output from the child device to the one multi-optical axis photoelectric sensor which is the parent device, and the one multi-light receiving the same The shaft photoelectric sensor outputs a light shielding signal to the outside. In addition, the other multi-optical axis photoelectric sensor is a master unit with respect to still another multi-optical axis photoelectric sensor connected thereto, and the further other multi-optical axis photoelectric sensor is a slave unit. Further, the other multi-optical axis photoelectric sensor that is the slave unit outputs a light shielding signal to the other multi-optical axis photoelectric sensor that is the master unit, and receives the other multi-optical axis photoelectric sensor. The sensor outputs a light shielding signal to the one multi-optical axis photoelectric sensor described above, which is a master unit with respect to the other multi-optical axis photoelectric sensor, and the one multi-optical axis photoelectric sensor outputs the light shielding signal to the outside. Output.

  An object of the present invention is to connect a plurality of sets of multi-optical axis photoelectric sensors in series to operate as one light curtain, and to connect cables and / or light receivers between projectors of a master unit and a slave unit. It is an object of the present invention to provide a multi-optical axis photoelectric sensor that can determine whether a cable for connecting is poorly connected or not connected.

  A further object of the present invention is to provide a multi-optical axis photoelectric sensor capable of automatically recognizing whether or not the usage mode is connected to a slave unit.

According to the present invention, the above technical problem is
A multi-optical axis photoelectric sensor consisting of a set of a projector and a receiver has a connector for connecting a slave unit and a connector for connecting a master unit, and a plurality of multi-optical axis photoelectric sensors are connected in series using a cable. The optical axis photoelectric sensor is a multi-optical axis photoelectric sensor that operates as a base unit or a slave unit from a relative connection relationship, and can be used as a single light curtain.
A serial connection recognition terminal provided in the connector for connecting the slave unit of at least one of the projector or the receiver;
A switch capable of switching the potential of the serial connection recognition terminal between a first potential indicating normality and a second potential indicating abnormality;
When the second potential is applied to the serial connection recognition terminal by the switch, the cable is connected to another multi-optical axis photoelectric sensor by the cable, so that the potential of the serial connection recognition terminal changes to the first potential. ,
Provided is a multi-optical axis photoelectric sensor that operates normally when the series connection recognition terminal is at a first potential and outputs an abnormal signal when the terminal is at the second potential. Is achieved.

  The switch is preferably a manual switch that is typically operated by a user. By causing the user to operate the manual switch, it is possible to know whether or not the user intends to connect the slave unit to the multi-optical axis photoelectric sensor. Although the user intends to connect the slave unit, when the cable is not connected, the potential of the serial connection recognition terminal takes the second potential. Since the multi-optical axis photoelectric sensor includes control means such as a CPU and a gate array, the control means can be used to determine abnormality. When it is determined that there is an abnormality, the light shielding signal may be output by the output means inherent to the multi-optical axis photoelectric sensor, and when the multi-optical axis photoelectric sensor is provided with the display means, You may make it notify a user of abnormality by a display means.

  The slave unit connector is generally covered with a connector cover when not used. It is preferable to operate the switch using the connector cover as an operation member. As a result, it is possible to discriminate between a normal state and an abnormal state including the connection state of the cable only by performing the same work as the work contents so far.

According to another aspect of the present invention, in order to achieve the above technical problem,
A multi-optical axis photoelectric sensor consisting of a set of a projector and a receiver has a connector for connecting a slave unit and a connector for connecting a master unit, and a plurality of multi-optical axis photoelectric sensors are connected in series using a cable. The optical axis photoelectric sensor is a multi-optical axis photoelectric sensor that operates as a base unit or a slave unit from a relative connection relationship, and can be used as a single light curtain.
A memory for storing an initial state of the light curtain when the light curtain is constructed by the multi-optical axis photoelectric sensor, provided in at least one of a projector or a light receiver of the multi-optical axis photoelectric sensor;
Comparison means for comparing the initial state of the light curtain and the current state of the light curtain stored in the memory by a trigger from inside or outside the multi-optical axis photoelectric sensor;
There is provided a multi-optical axis photoelectric sensor having an output means for outputting an abnormal signal when the current state of the light curtain is different from the initial state by the comparing means.

  Typical information preferable as the initial state of the light curtain typically includes the number of optical axes of the light curtain, but may be the number of multi-optical axis photoelectric sensors. Most preferably, the memory that stores the initial state of the light curtain is a non-volatile memory. This makes it easy to maintain the information stored in the memory even when the light curtain is turned off.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a multi-optical axis photoelectric sensor 1. The illustrated multi-optical axis photoelectric sensor 1 includes a pair of a projector and a light receiver that are paired with each other, and the light projector and the light receiver have substantially the same appearance. The multi-optical axis photoelectric sensor 1 is formed of an aluminum extruded material and has a main body case 2 that is open at both ends, and an end case 3 that is disposed at both ends of the main body case 2, and has an elongated outer shape. The end case 3 has a shape in which one end is open and the other end is closed, and is made of a plastic molded product or a die-cast molded product of zinc or aluminum. Inside the multi-optical axis photoelectric sensor 1, light projecting elements or light receiving elements incorporated in the main body case 2 and the end case 3 are arranged at equal intervals.

  The light projecting surface or light receiving surface 4 of the multi-optical axis photoelectric sensor 1 is composed of a front cover that allows light of a specific wavelength to pass through. A light beam is emitted from the light projector through the front cover 4 or from the light projector. A light beam is incident on the receiver. The front cover 4 includes a main cover 4a substantially corresponding to the main body case 2 and an end cover 4b substantially corresponding to the end case 3. The main cover and the end covers 4a and 4b are different from each other. It is a part.

  The end case 3 has a connector opening 5, and each connector opening 5 opens from the back side to the front side of the end case 3, and as shown in FIG. By pushing toward the back side of the multi-optical axis photoelectric sensor 1, it is possible to connect to a control device (not shown) or another adjacent multi-optical axis photoelectric sensor through the cable 7.

  Returning to FIG. 1, one connector opening 5 </ b> A among the connector openings 5 provided at both ends of the multi-optical axis photoelectric sensor 1 is a slave unit connection opening for connecting the slave units in series. The connector opening 5B is an opening for a master unit or an external output. 1 and 2, reference numeral 8 indicates a recess formed in the end case 3, and the end of the cable 7 is accommodated in the recess 8. Further, in FIG. 1, reference numeral 9 indicates a band-shaped metal part disposed at the boundary between the main cover 4a and the end cover 4b, and the band-shaped metal part 9 is not shown in FIG. .

  FIG. 3 shows an example in which three sets of multi-optical axis photoelectric sensors 1 are connected in series, and three sets of multi-optical axis photoelectric sensors 1 are identified by adding A, B, and C thereto. In the figure, reference numerals 100 and A, B, and C are assigned to the projectors constituting the multi-optical axis photoelectric sensors 1A, 1B, and 1C, and reference numerals 200 and A are assigned to the light receivers. , B and C are attached. Note that, when the three sets of multi-optical axis photoelectric sensors 1A to 1C are collectively described, they are simply described with reference numeral “1”. Similarly, the projectors 100A to 100C and the light receivers 200A to 200C will be described by simply adding “100” or “200” when they are collectively described. The three sets of multi-optical axis photoelectric sensors 1A to 1C connected in series with each other by the dedicated cable 7 operate as one light curtain, and when the operator's hand or finger or some object IS blocks the optical axis and blocks light, A light-shielding signal is output from the first light receiver 200A through the cable 10a.

  FIG. 4 shows the internal structure of the multi-optical axis photoelectric sensor 1. Referring to FIG. 4, projector 100 includes N drive circuits 102 that drive N projector elements 101, a projector element switching circuit 103 that scans these drive circuits 102 in a time-sharing manner, and projector 100. And a projector control circuit 104 for overall control. The projector control circuit 104 may be composed of a CPU or a dedicated gate array.

  The projector control circuit 104 receives the clock signal from the clock generation circuit 105 and generates the light projection timing for sequentially emitting the N light projecting elements 101. Thus, one N light projecting element 101 is provided. Light is emitted at a predetermined timing.

  The projector 100 further controls communication between the first projector communication control circuit 106 that controls bidirectional transmission / reception with the projector 100 or the light receiver 200 of the master unit and the projector 100 of the slave unit. And a second projector communication control circuit 107.

  On the other hand, the light receiver 200 includes N drive circuits 202 that drive the N light receiving elements 201, a light receiving element switching circuit 203 that scans these drive circuits 202 in a time division manner, an amplifier circuit 204, and a light receiver 200. And a photoreceiver control circuit 205 for overall control. The photoreceiver control circuit 205 may be configured by a CPU or a dedicated gate array.

  In addition, the light receiver control circuit 205 receives a signal from the clock generation circuit 206 and sequentially activates the N light receiving elements 201 so that the light beam from the corresponding light projecting element 101 can be received. On the other hand, light other than the selected light receiving element 201 is disabled.

  The light receiver 200 is further connected between the first light receiver communication control circuit 207 that controls transmission and reception of bidirectional signals with the projector 100 or the light receiver 200 of the parent device, and the light receiver 200 of the child device. A light-receiving signal generated by the light-receiving control circuit 205 is sent to the light-receiving device 200 of the master unit or an external device such as a press machine via the output circuit 209. This stops the lighting of the warning light and the operation of the press.

  In the connection example of FIG. 3, the three sets of multi-optical axis photoelectric sensors 1A to 1C have a relative connection relationship, and the lower set of multi-optical axis photoelectric sensors 1A operate as a master unit, and the multi-optical axis in the middle. A set of photoelectric sensors 1B operates as a slave unit with respect to the lowermost multi-optical axis photoelectric sensor 1A. The middle group of multi-optical axis photoelectric sensors 1B operates as a master unit for the uppermost group of multi-optical axis photoelectric sensors 1C, and the uppermost multi-optical axis photoelectric sensor 1C operates as a slave unit.

  In the projector 100A of the lowermost multi-optical axis photoelectric sensor 1, first, synchronization timing is generated by the projector control circuit 104, and this synchronization timing is transmitted via the cable 10b to the receiver communication control circuit 107 of the lowermost receiver 200A. To the light receiver control circuit 205, and the N drive circuits 102 of the lowermost multi-optical axis photoelectric sensor 1A, the N drive circuits 102 of the light receiver 200A, and the corresponding drive circuits 202 operate one by one. Further, the light shielding signal generated by the light receiver control circuit 205 is supplied to the outside through the output circuit 209 and the cable 10a.

  Regarding the light projection and reception in the three sets of multi-optical axis photoelectric sensors 1A to 1C, a timing signal of light projection and light reception is supplied from the lowest multi-optical axis photoelectric sensor 1A to the next multi-optical axis photoelectric sensor 1B, and the middle multi-light The timing signal of light projection / reception is supplied from the axial photoelectric sensor 1B to the next uppermost multi-optical axis photoelectric sensor 1C, whereby all the light in the light curtain composed of the three sets of multi-optical axis photoelectric sensors 1A to 1C is supplied. The shaft sequentially performs light projection and reception at a predetermined timing. When no light is received in the process, a light shielding signal is output by the output circuit 209.

  FIG. 5 illustrates that the multi-optical axis photoelectric sensors 1 and 1 are connected in series by a dedicated cable 7, and FIG. 6 is a connection diagram related thereto. FIG. 5 also shows that the slave unit connection opening 5A of the multi-optical axis photoelectric sensor 1 can be covered with the connector cover 12, and FIG. 7 is a connection diagram related thereto.

  The sensor side connector 13 facing the slave unit connection opening 5A of the multi-optical axis photoelectric sensor 1 includes a power connection terminal 13a, a ground connection terminal 13b, a communication (+) connection terminal 13c, and a communication (-) connection terminal 13d. In addition, a serial connection recognition terminal 13e for detecting the presence / absence of connection of the slave unit is provided, and one end of an identification resistor 15 is connected to the identification wiring 14 connected to the serial connection recognition terminal 13e. . On the other hand, the sensor-side connector 17 facing the base unit connection opening 5B of the multi-optical axis photoelectric sensor 1 includes a power connection terminal 17a, a ground connection terminal 17b, a communication (+) connection terminal 17c, and a communication (-) connection. In addition to the terminal 17d, a grounded connection terminal 17e is provided.

  The cable-side connectors 6 at both ends of the cable 7 that connects the multi-optical axis photoelectric sensor 1 in series are provided with connector pins 6a to 6e that can enter the connection terminals 13a to 13e and 17a to 17e.

  The slave unit connection opening 5 </ b> A of the multi-optical axis photoelectric sensor 1 can accept the connector cover 12 instead of the connector 6 of the serial connection cable 7. The connector cover 12 has pins 12 a and 12 b that can be connected to the ground connection terminal 13 b and the series connection recognition terminal 13 e, and these two connection pins 12 a and 12 b are connected by an internal wiring 18.

  In the above configuration, when the multi-optical axis photoelectric sensors 1 and 1 are connected to each other by the series connection cable 7, the series connection recognition terminal 13e of the sensor side connector 13 facing the slave unit connection opening 5A on the master unit side is provided. The terminal is connected to the grounded connection terminal 17e on the slave unit side via the cable 7, so that the connection terminal 17e on the master unit side is short-circuited, and the potential becomes the GND potential, that is, "L". When the connector cover 12 is attached to the slave unit connection opening 5A on the master unit side, the serial connection recognition terminal 13e of the sensor side connector 13 is connected via the connection pins 12a and 12b and the internal wiring 18 of the connector cover 12. Is connected to the ground connection terminal 13b and short-circuited, so that the series connection recognition terminal 13e on the parent device side becomes the GND potential, that is, "L".

  On the other hand, when either one of the cable-side connectors 6 and 6 at both ends of the cable 7 is disconnected, the serial connection recognition terminal 13e of the sensor-side connector 13 on the base unit side is not connected. The potential of the serial connection recognition terminal 13e is “H”. Similarly, when the cable 7 is disconnected, the potential of the serial connection recognition terminal 13e is “H”.

  The above aspect will be described with reference to FIG. 3. When a user constructs a light curtain by connecting three sets of multi-optical axis photoelectric sensors 1A to 1C in series, the uppermost projector / receiver 100C, The connector cover 12 is attached to the 200C child machine connection opening 5A. In this aspect, the series connection recognition terminal 13e of the uppermost projector / receiver 100C, 200C has a fixed value, that is, a GND potential ("L"). When the connector cover 12 is not attached, the potential of the serial connection recognition terminal 13e of the light emitter / receiver 100C, 200C is “H”. Then, by connecting the slave unit to the uppermost projector / receiver 100C, 200C, the serial connection recognition terminal 13e of the projector / receiver 100C, 200C becomes the GND potential ("L"). Therefore, the GND potential can be directly input to the control circuits 104 and 205 of the projector / receiver 100C and 200C, for example, and can be determined by the control circuits 104 and 205 to be in a normal state.

  On the other hand, at least one of the two cables 7 connecting the lowermost projector / receiver 100A, 200A and the projector / receiver 100B, 200B in the middle of the slave unit is disconnected or the connectors at both ends of the cable 7 are disconnected. When either one of 6 or 6 is disconnected, the logical value of the serial connection recognition terminal 13e of the projector / receiver 100A and / or 200A, which is the master unit, is “H”. Thus, for example, the control circuits 104 and 205 of the projector / receivers 100A and 200A of the master unit can determine that an abnormality has occurred, and immediately output a light shielding signal, for example, to notify the user of the abnormality. Further, when each multi-optical axis photoelectric sensor 1 is provided with an indicator light such as a display LED, the user can be informed of the abnormality by lighting or blinking the indicator light.

  According to the above embodiment, the serial connection recognition terminal 13e is connected to the connector cover 12 covering the slave unit connection opening 5A of the multi-optical axis photoelectric sensor 1 when the connector cover 12 is attached and when it is not attached. The logic value is configured to change, and when the connector cover 12 is attached, the logic value indicating normality is taken, and when the cable 7 is connected, the logic value indicating normality is also taken. is there. Accordingly, the fact that the connector cover 12 is not attached and the cable 7 is not connected is in a state different from the user's intention, and in this unintended state, the logical value of the serial connection recognition terminal 13e indicates an abnormality. Since the logic value is taken, the change in the logic value can be used to notify the user of connection failure or disconnection of the cable-side connector 6 or disconnection of the cable 6.

  That is, when the connector cover 12 is attached, the connector cover 12 can be operated assuming that there is no slave unit associated with the multi-optical axis photoelectric sensor 1. Further, when the multi-optical axis photoelectric sensors 1 and 1 are connected in series by the cable 7, the connection of the multi-optical axis photoelectric sensor 1 of the master unit is recognized depending on whether the connection is normal or abnormal. Since the terminal 13e has a different logic value and becomes “L” when normal, and “H” when abnormal, the change in the potential of the serial connection recognition terminal 13e is used to determine whether the cable 7 is poorly connected or not. It is possible to detect that the connection or the cable 7 is disconnected, and thereby output a light shielding signal to notify the user of the abnormality. Further, when each multi-optical axis photoelectric sensor 1 is provided with an indicator light such as a display LED, the user can be informed of the abnormality by lighting or blinking the indicator light.

  In addition, the control circuits 104 and 205 correspond to the number of optical axes instead of determining whether or not the logical value H or L as described above is supplied as a signal supplied to the serial connection recognition terminal 13e. You may make it detect abnormality by determining whether a pulse signal is supplied at a timing.

  Further, instead of directly monitoring the serial connection recognition terminal 13e by the control circuits 104 and 205, an error is caused in an error check circuit other than the serial connection confirmation based on a logical value indicating that the serial connection recognition terminal 13e is abnormal. A simple circuit may be provided. Here, the error check circuit other than the serial connection check is, for example, a check circuit for the number of optical axes, such as a check circuit for checking whether the light projecting drive circuit or the light receiving drive circuit of each optical axis is operating normally. . For example, in the case of a check circuit for the number of optical axes, causing an error in the error check circuit reduces the count number of the optical axis or sets the count number to exceed the maximum number of optical axes allowed by the multi-optical axis photoelectric sensor. Etc. Thus, by sharing the monitoring of the serial connection recognition terminal 13e with other error check circuits, the routing of wiring is reduced and the burden on the control circuits 104 and 205 is reduced.

  The above configuration is most preferably provided in both the light projector 100 and the light receiver 200, but may be provided in either one. For example, in the case where the projector 100 is provided only in the projector 100, a connection failure of the cable 7 that connects between the master unit and the slave unit of the projector 100 can be detected immediately on the master unit side by the above configuration. When the connection failure of the cable 7 or the like occurs on the light receiver 200 side that does not have the above configuration, the user is abnormal due to the light shielding signal that is output with the above-described mismatch of the number of optical axes with the projector 100. I can inform you.

  As described above, according to the configuration of the embodiment, when the connection between the master unit and the slave unit connected in series is disconnected, this can be detected on the master unit side, thereby displaying the master unit. It is possible to notify the user of an abnormality in the light curtain by turning on or blinking the lamp or outputting a light shielding signal. In addition, it is possible to immediately detect the connection failure of the slave unit without changing the work contents conventionally performed such as attaching / detaching the connector cover 12 or attaching the serial connection cable 7. In addition, only by performing the same work as before, it is possible to prevent incomplete operation of the light curtain due to disconnection or poor connection between the master unit and the slave unit and disconnection of the cable.

As mentioned above, although the preferable Example of this invention was described, this invention is not limited to this, The following modification is included.
(1) In the above embodiment, the connector cover 12 is provided with the connection pins 12a and 12b connectable to the ground connection terminal 13b and the series connection recognition terminal 13e. At least one of the projector 100 or the light receiver 200 of the photoelectric sensor 1 is provided with a manually operated switch such as a dip switch so that the switch is switched between when the slave unit is not connected and when the slave unit is connected. Also good.

(2) After providing a non-volatile memory in at least one of the projector 100 or the light receiver 200 of the multi-optical axis photoelectric sensor 1 and the user constructs the light curtain using the multi-optical axis photoelectric sensor 1, for example, the power source of the light curtain Light curtains such as the number of optical axes of the initial light curtain and the number of multi-optical axis photoelectric sensors 1 by turning on, teaching switches, external inputs, or operations from external devices such as personal computers and handheld consoles connected separately Is stored in the non-volatile memory, and a means for determining whether or not the initial state of the light curtain stored in the memory and the current light curtain state is the same is provided. When it is detected that the light curtain is different from the initial state, May be notified the user of the abnormality display lamp of the multi-optical axis photoelectric sensor 1 outputs a light or or shading signal is flashing Chi.

(3) After the user constructs a light curtain using the multi-optical axis photoelectric sensor 1, the number of light axes of the light curtain, the number of the multi-optical axis photoelectric sensor 1 and the like are determined according to external devices such as personal computers and handy console units. By communicating between the light curtain and external equipment when the repair of the press in the hazardous area partitioned by the light curtain is completed, or periodically, or when the light curtain is turned on Compare the number of light axes of the current light curtain and the initial state of the light curtain stored in the external device to determine whether the current light curtain is the same as the initial state. When different from the above, an alarm may be issued to the user such as lighting of an indicator lamp.

(4) Whether the past or previous connection information stored in the memory provided in the multi-optical axis photoelectric sensor 1 matches the current connection information using the communication function between the multi-optical axis photoelectric sensors 1 and 1 If there is a discrepancy, the user may be notified of the abnormality by turning on an indicator lamp provided in the multi-optical axis photoelectric sensor 1. The confirmation as to whether or not they match may be triggered by turning on the power of the light curtain or triggered by an input from an external device. It is preferable that the connection information stored in the memory can be updated for the first time by a user's artificial input operation, for example, by turning on a manual switch provided in the multi-optical axis photoelectric sensor 1.

It is a figure for demonstrating the external shape of a multi-optical axis photoelectric sensor. It is a figure for demonstrating the connection port for connectors provided in the edge part of a multi-optical axis photoelectric sensor, and the cable for series connection fitted in this. It is a figure which shows the example of a connection which connects 3 sets of multi-optical axis photoelectric sensors in series, and operate | moves as one light curtain. It is a block diagram which shows the structure of the light projector and light receiver which comprise a multi-optical axis photoelectric sensor. It is a figure for demonstrating selectively using the cable for connecting a multi-optical axis photoelectric sensor, and the connector cover which covers the connector connection port of a multi-optical axis photoelectric sensor when not connecting a subunit | mobile_unit. It is a figure for demonstrating the connection relation when connecting a multi-optical axis photoelectric sensor using a cable. It is a figure for demonstrating the connection relation when the connector for a subunit | mobile_unit connection of a multi-optical axis photoelectric sensor is covered with the connector cover.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-optical axis photoelectric sensor 5A Slave unit connection connector opening 5B Master unit or external output connector opening 6 Cable side connector 7 Dedicated cable for serial connection 12 Connector cover 13 Sensor side connector 13e Series connection recognition terminal 100 Flood projector 103 Flood projector Control circuit 200 Light receiver 205 Light receiver control circuit 209 Shading signal output circuit

Claims (12)

A multi-optical axis photoelectric sensor consisting of a set of a projector and a receiver has a connector for connecting a slave unit and a connector for connecting a master unit, and a plurality of multi-optical axis photoelectric sensors are connected in series using a cable. The optical axis photoelectric sensor is a multi-optical axis photoelectric sensor that operates as a base unit or a slave unit from a relative connection relationship, and can be used as a single light curtain.
A serial connection recognition terminal provided in the connector for connecting the slave unit of at least one of the projector or the receiver;
A switch capable of switching the potential of the serial connection recognition terminal between a first potential indicating normality and a second potential indicating abnormality;
When the second potential is applied to the serial connection recognition terminal by the switch, the cable is connected to another multi-optical axis photoelectric sensor by the cable, so that the potential of the serial connection recognition terminal changes to the first potential. ,
The multi-optical axis photoelectric sensor, wherein the multi-optical axis photoelectric sensor operates normally when the series connection recognition terminal is at a first potential, and outputs an abnormal signal when the terminal is at the second potential.   The multi-optical axis photoelectric sensor according to claim 1, wherein the switch is a manual switch operated by a user.   The operation member of the switch is constituted by a connector cover that covers the slave unit connection connector, and when the user attaches the connector cover to the slave unit connection connector, the potential of the serial connection recognition terminal is the first potential. The multi-optical axis photoelectric sensor according to claim 2, wherein when the connector cover is not attached, the potential of the serial connection recognition terminal becomes the second potential. A multi-optical axis photoelectric sensor consisting of a set of a projector and a receiver has a connector for connecting a slave unit and a connector for connecting a master unit, and a plurality of multi-optical axis photoelectric sensors are connected in series using a cable. The optical axis photoelectric sensor is a multi-optical axis photoelectric sensor that operates as a base unit or a slave unit from a relative connection relationship, and can be used as a single light curtain.
A memory for storing an initial state of the light curtain when the light curtain is constructed by the multi-optical axis photoelectric sensor, provided in at least one of a projector or a light receiver of the multi-optical axis photoelectric sensor;
Comparison means for comparing the initial state of the light curtain and the current state of the light curtain stored in the memory by a trigger from inside or outside the multi-optical axis photoelectric sensor;
A multi-optical axis photoelectric sensor comprising: an output unit that outputs an abnormal signal when the current state of the light curtain is different from an initial state by the comparison unit.   The number of optical axes of the light curtain is stored in the memory as an initial state of the light curtain, and the number of optical axes in the initial state is compared with the current number of optical axes by the comparison unit. Multi-optical axis photoelectric sensor.   The multi-optical axis photoelectric sensor according to claim 4 or 5, wherein the memory is a nonvolatile memory. A multi-optical axis photoelectric sensor consisting of a set of a projector and a light receiver has a connector for connecting a slave unit and a connector for connecting a master unit, and a plurality of cables are connected using a cable detachably connected to the connector of the multi-optical axis photoelectric sensor. By connecting the multi-optical axis sensors in series, each multi-optical axis photoelectric sensor supplies the detection information to the master unit or the master unit that supplies at least one of the power and the synchronization signal to the slave unit from the relative connection A multi-optical axis photoelectric sensor that operates as a slave and can be used as a single light curtain,
At least one of the light projector or the light receiver is a first terminal for recognizing series connection provided on the connector for connecting a slave unit and a second terminal different from the first terminal provided on the connector for connecting a slave unit And a circuit for recognizing series connection connected to the connector for connecting the master unit,
The cable includes a first conductor connected to the first terminal for serial connection recognition, and a second conductor connected to the second terminal and insulated from the first conductor in the cable,
The cable is connected to a connector for connecting a slave unit and a connector for connecting a master unit of another multi-optical axis photoelectric sensor, whereby the first conductor of the cable, the second conductor of the cable, and the first conductor The first terminal and the second terminal are connected by a connection circuit consisting of the series connection recognition circuit provided in the other multi-optical axis photoelectric sensor connected to the second conductive wire,
The multi-optical axis photoelectric sensor operates normally when the cable is connected, and operates in an abnormal state when the cable is not connected.   The multi-optical axis photoelectric sensor supplies a first signal indicating normality to the first terminal for serial connection recognition by being connected to the connection circuit when the cable is connected, and when the cable is not connected, The multi-optical axis photoelectric sensor according to claim 7, further comprising a signal circuit that supplies a second signal indicating abnormality to the first terminal for serial connection recognition.   The multi-optical axis photoelectric sensor according to claim 7 or 8, wherein the series connection recognition circuit is a circuit that short-circuits the first conductor and the second conductor.   The multi-optical axis photoelectric sensor has a connector cover containing a circuit equivalent to the series connection recognition circuit connected to the connector for connecting the slave unit. The multi-optical axis photoelectric sensor according to any one of claims 7 to 9, wherein two terminals are connected and the connector cover operates normally when connected.   A multi-optical axis photoelectric sensor in which the connector cover is connected to a connector for connecting a slave unit of a multi-optical axis photoelectric sensor disposed at the end as the slave unit, and the multi-optical axis photoelectric sensor is relatively disposed as a master unit When the cable is connected to the connector for connecting the slave unit and the connector for connecting the master unit to the corresponding slave unit, when the cable is connected and at least one of the connector cover and the cable is not connected The multi-optical axis photoelectric sensor according to claim 10, which operates in an abnormal state.   The multi-optical axis photoelectric sensor includes a mechanical switch capable of short-circuiting the first terminal and the second terminal, and the first multi-optical axis photoelectric sensor is connected to the first terminal and the first terminal by the mechanical switch. The multi-optical axis photoelectric sensor according to any one of claims 7 to 9, which operates normally by short-circuiting two terminals.

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