System with one sensor and method with one sensor for monitoring multiple protection areas

Abstract

System (1) with at least one sensor (2) for monitoring several protection zones (SB1, SB2, SB3, SB4) for violation by at least one object (3) and with a control unit (4) for controlling a system to be protected (5) with a mechanically moving part (6), with the sensor (2) for at least area-wide monitoring of the protection zones (SB1, SB2, SB3, SB4) with a control and evaluation unit (7) for evaluating the received signals of the sensor (2) in order to determine which of the protection zones (SB1, SB2, SB3, SB4) is violated by the object (3), hereinafter referred to as protection zone violation, and which protection zone (SB1, SB2, SB3, SB4) the object (3) has left, hereinafter referred to as protection zone release, with the control (4) for generating and outputting a switching signal which is an enable signal for enabling plant operation, wherein the controller (4) is configured to output the release signal when the controller (4) detects a predetermined sequence of events, wherein the events consist of protection area violations and protection area releases of the protection areas (SB1, SB2, SB3, SB4) and each event is either a protection area violation or a protection area release, wherein the mechanically movable part has a first working area (AB1) and a second working area (AB2), wherein the mechanically movable part (6) is located either in the first working area (AB1) or in the second working area (AB2), where the first work area (AB1) is assigned a first protection area (SB1) and a second protection area (SB2), wherein the first protection area (SB1) borders the first work area (AB1) and the second protection area (SB2) borders the first protection area (SB1), wherein the first protection area (SB1) is only accessible via the second protection area (SB2), where the second work area (AB2) is assigned a third protection area (SB3) and a fourth protection area (SB4), wherein the third protection area (SB3) borders the second work area (AB2) and the fourth protection area (SB4) borders the third protection area (SB3), wherein the third protection area (SB3) is only accessible via the fourth protection area (SB4), wherein the control (4) is configured to start the mechanically moving part (6) when an object (3) has left the first protection area (SB1) and then the second protection area (SB2), thereby providing a protection area release in the first protection area (SB1) and subsequently in the second protection area (SB2) or An object (3) has left the third protection zone (SB3) and then the fourth protection zone (SB4), resulting in a protection zone release in the third protection zone (SB3) and subsequently in the fourth protection zone (SB4), whereby, if the mechanically moving part (6) is active in the first working area (AB1), in the event of protection zone violations in the fourth protection zone (SB4), the control (4) is configured to switch the mechanically moving part (6) into a safe working mode. and in the event of a breach of the protection zone in the second protection zone (SB2), the control unit (4) is designed to stop the mechanically moving part (6), whereby if the mechanically moving part (6) is active in the second working area (AB2), in the event of a breach of the protection zone in the second protection zone (SB2), the control unit (4) is designed to switch the mechanically moving part (6) into a safe working mode. and in the event of violations of the protection area in the fourth protection area (SB4), the control (4) is designed to stop the mechanically moving part (6).

Description

[0001] The present invention relates to a system with a sensor for monitoring a plurality of protection areas for violation by at least one object according to the preamble of claim 1 and to a method with a sensor for monitoring a plurality of protection areas for violation by at least one object according to the preamble of claim 8.

[0002] EP 3 153 885 B1 discloses an optoelectronic protective device for optically monitoring a plurality of protection areas for violation by at least one object and for controlling a system to be protected, with a sensor to determine which of the protection areas is violated by the object, hereinafter referred to as protection area violation, and which protection area the object has left, hereinafter referred to as protection area release, with a controller for generating and outputting a switching signal which is an enable signal for enabling system operation, wherein the controller is designed to output the enable signal only when the controller detects a predetermined sequence of events, wherein the events consist of protection area violations and protection area releases of the protection areas and each event is either a protection area violation or a protection area release.

[0003] DE 10 2019 111 640 A1 discloses a method for securing at least one hazard point of a hazardous machine, wherein objects in the vicinity of the hazard point are detected from measurement data of at least one 3D sensor and, in the event of imminent danger, a safety-related reaction of the machine takes place, wherein, during operation of the machine, switching to at least one newly secured hazard point is carried out and a check is carried out to determine whether the newly secured hazard point is free of objects.

[0004] DE 20 2018 103 012 U1 discloses a device for securing a danger zone of a system controlled by a controller, with a sensor arrangement by means of which a protection zone adapted to the danger zone is monitored, wherein upon detection of an object penetrating the protection zone by means of the sensor arrangement a switching signal is generated by means of which dangerous operation of the system is stopped, characterized in that the sensor arrangement detects the movement sequence of the object when leaving the protection zone, and that upon registration of a valid movement sequence by means of the sensor arrangement a release signal is generated by means of which the dangerous operation of the system is reactivated.

[0005] DE 10 2013 111 570 A1 discloses a work cell arrangement with a protected work area surrounded by a protective device with multiple protective elements. The work area is divided into a first and a second work cell by a separating device. The separating device is adjustable between a first and a second working position, so that in the first working position, the first work cell is larger than in the second working position, and the second work cell is larger in the second working position than in the first working position, the size of the work area remaining constant. The invention further relates to a robot cell arrangement with such a work cell arrangement.

[0006] An object of the invention is to provide an improved system for object detection which has a higher availability.

[0007] The object is achieved according to claim 1 by a system with at least one sensor for monitoring a plurality of protection areas for violation by at least one object and with a controller for controlling a system to be protected with a mechanically movable part, with the sensor for at least surface-level monitoring of the protection areas with a control and evaluation unit for evaluating the received signals from the sensor in order to determine which of the protection areas is violated by the object, hereinafter referred to as protection area violation, and which protection area the object has left, hereinafter referred to as protection area release, with the controller for generating and outputting a switching signal which is a release signal for releasing the system operation.

[0008] The controller is configured to output the release signal when the controller detects a predetermined sequence of events, wherein the events consist of protection area violations and protection area releases of the protection areas, and each event is either a protection area violation or a protection area release.

[0009] The mechanically movable part has a first working area and a second working area, wherein the mechanically movable part is located either in the first working area or in the second working area, wherein a first and a second protection area are assigned to the first working area, wherein the first protection area borders on the first working area and the second protection area borders on the first protection area, wherein the first protection area can only be reached via the second protection area, wherein a third and a fourth protection area are assigned to the second working area, wherein the third protection area borders on the second working area and the fourth protection area borders on the third protection area, wherein the third protection area can only be reached via the fourth protection area.

[0010] The control system is designed to start the mechanically movable part when an object has left the first protection area and then the second protection area, whereby a protection area release exists in the first protection area and then in the second protection area, or an object has left the third protection area and then the fourth protection area, whereby a protection area release exists in the third protection area and then in the fourth protection area, wherein when the mechanically movable part is active in the first working area, in the event of protection area violations in the fourth protection area, the control system is designed to switch the mechanically movable part to a non-hazardous working mode and in the event of protection area violations in the second protection area, the control system is designed to stop the mechanically movable part,Wherein, if the mechanically movable part is active in the second working area, in the event of protection area violations in the second protection area, the control is designed to switch the mechanically movable part into a safe working mode and, in the event of protection area violations in the fourth protection area, the control is designed to stop the mechanically movable part.

[0011] The object is further achieved according to claim 8 with a method having at least one sensor for monitoring several protection areas.

[0012] The mechanically movable part can, for example, be a driven mechanism, in particular a robot, a robot part, a movable machine part or the like.

[0013] With the solution according to the invention, the mechanically moving part is not stopped when workpieces are picked up or placed in the work area in which the mechanically moving part is not currently operating. If the mechanically moving part is operating in the first work area, workpieces can be picked up or placed in the second work area. If the mechanically moving part is operating in the second work area, workpieces can be picked up or placed in the first work area. This offers the advantage of increased productivity.

[0014] For this purpose, the area in front of the mechanically moving part, for example, a loading robot with two loading stations, is divided into two work areas, for example, a right and left work area, or even a first and second work area. Two protective fields are assigned to each of the two work areas, so that a total of four protective areas or protective fields are monitored simultaneously.

[0015] The protective fields can also be monitored with two or more sensors. A single first sensor can, for example, monitor the first and second protective zones, and a single second sensor can, for example, monitor the third and fourth protective zones. It can also be provided that a single first sensor monitors the second and fourth protective zones, and a single second sensor monitors the first and third protective zones.

[0016] In the first and second protection areas and in the third and fourth protection areas, an independent sequence monitoring is implemented in which the entry and exit sequence is monitored.

[0017] An object or person must first enter the second protection zone and then the first protection zone to be legally able to reach the first work zone. If the first protection zone is entered without first entering the second protection zone, the mechanically moving part is stopped immediately.

[0018] Likewise, an object or person must first enter the fourth protection zone and then the third protection zone to be legally able to reach the second work zone. If the third protection zone is entered without first entering the fourth protection zone, the mechanically moving part is stopped immediately.

[0019] A step behind is detected by the protection areas becoming free in the specified order.

[0020] However, in the event of a permissible entry into the first or third protective field, i.e., in the event of a previously described entry via the second and fourth protective fields, a stop of the mechanically moving part is not always initiated. For example, if the mechanically moving part is operating in the second work area, a permissible entry into the first protective field does not initiate a stop of the mechanically moving part, since the person in the first protective zone is in a safe area. Sequence monitoring remains active to detect stepping behind.

[0021] This allows a workpiece to be picked up or placed in the first work zone without stopping the mechanically moving part. To ensure safety when a person comes close to the mechanically moving part, interrupting the second protection zone can, for example, reduce the speed of the mechanically moving part or switch to collaborative operation.

[0022] This allows workpieces to be picked up or set down in the second work zone without stopping the mechanically moving part. To ensure safety when a person comes close to the mechanically moving part, the fourth protection zone is interrupted, for example, by reducing the speed of the mechanically moving part or switching it to collaborative operation.

[0023] The advantage is that the mechanically moving part can continue to operate productively while a person can simultaneously pick up or set down the other workpiece. A manual reset or automatic restart is not necessary.

[0024] The protection areas or protective fields can, for example, have any shape or be configured with any shape. For example, parts of the protection areas or protective fields can be straight, curved, circular, and / or elliptical. The shape of the protection areas is only limited by the angular and distance resolution of the sensor.

[0025] In a further development of the invention, the mechanically movable part is a mechanically movable part for loading pallets, wherein a pallet is present in the first working area and / or in the second working area.

[0026] According to the further development, the mechanically moving part is not stopped if a pallet is picked up or placed in the work area in which the mechanically moving part is not currently operating. If the mechanically moving part is operating in the first work area, a pallet can be picked up or placed in the second work area. If the mechanically moving part is operating in the second work area, a pallet can be picked up or placed in the first work area. This offers the advantage of increased productivity in the automated loading of pallets.

[0027] In a further development of the invention, the controller is designed to generate the stop signal if a protection area is violated and the predetermined sequence has not been completed.

[0028] An object or person must first enter the second protection zone and then the first protection zone to be legally able to reach the first work zone. If the first protection zone is entered without first entering the second protection zone, the mechanically moving part is stopped immediately.

[0029] Likewise, an object or person must first enter the fourth protection zone and then the third protection zone to be legally able to reach the second work zone. If the third protection zone is entered without first entering the fourth protection zone, the mechanically moving part is stopped immediately.

[0030] In a further development of the invention, the controller includes a timer so that the controller can monitor whether successive events, i.e., successive protected area violations or successive protected area releases, occur within specific time windows. The timers are tuned, for example, to the movement speed of a person as an object.

[0031] In a further development of the invention, the sensor is a laser scanner. A laser scanner is an optoelectronic sensor, wherein the transmitter is a light transmitter and the receiver is a light receiver for contactless scanning of the monitored area with the protected zones by transmitting light beams into the monitored area and detecting returning reflected light beams from objects within the monitored area. The control and evaluation unit evaluates the returning reflected light beams.

[0032] For example, a laser scanner is a time-of-flight sensor, i.e., a laser scanner based on time-of-flight analysis, or a time-of-flight camera. In particular, a laser scanner is a safety laser scanner or any optoelectronic environment detection sensor.

[0033] For example, a plurality of light transmitters and a plurality of light receivers are arranged, wherein the light transmitters and the light receivers are arranged in a common housing, wherein the light beams are emitted in different angular directions in a fan shape by the light transmitters and received by the light receivers, wherein a circular segment-shaped partial protection field is formed by the light beams of a light transmitter and a reception field of view of the light receiver, wherein the partial protection fields of adjacent reception elements adjoin one another and several partial protection fields form a protection area or a protection field.

[0034] This means the sensor does not require any mechanically moving parts. No rotating or oscillating mirror is required. This makes the sensor more robust against vibration and shock loads. Furthermore, the sensor without mechanically moving parts is more cost-effective and has a longer service life.

[0035] In an alternative embodiment, the laser scanner has a scanning unit rotatable about a rotation axis, with at least one scanning module for scanning the surveillance area during the rotation of the scanning unit about the rotation axis and for generating corresponding received signals as well as the control and evaluation unit for obtaining information about the objects from the received signals, wherein the scanning module comprises at least the light transmitter for emitting one light beam or several separate light beams and at least the light receiver for generating the received signals from the light beams remitted by objects.

[0036] According to the alternative embodiment, only a single light transmitter and only a single light receiver are necessary to generate the planar protection areas, since the light transmitter and the light receiver continuously detect the environment at different angles via the rotatable scanning unit.

[0037] In a further development of the invention, the sensor is a 3D camera for three-dimensional detection of the protection areas.

[0038] For example, the optoelectronic sensor for detecting objects in a three-dimensional surveillance area is designed with at least one image sensor which can record a pixel image of the surveillance area by means of a plurality of light-receiving elements, and with at least the control and evaluation unit which is designed to detect an object from image data of the pixel image, wherein a plurality of image sensors are provided, each having at least one pixel row with light-receiving elements and wherein the image sensors are arranged at a distance from one another so that each image sensor can record its own plane of the surveillance area, wherein the image sensors are arranged such that the planes are non-overlapping and substantially parallel to one another or diverge from one another in a fan-shaped manner starting from the image sensors.

[0039] The advanced development is based, for example, on the idea of ​​expanding existing, cost-effective area sensors. By duplicating and appropriately arranging such sensors, the monitoring of a three-dimensional spatial area is also possible.

[0040] In a further development of the invention, the sensor is a radar sensor.

[0041] According to the further development, the sensor is a radar sensor, wherein the transmitter is a radar transmitter, wherein the receiver is a radar receiver for contactless scanning of the monitoring area by transmitting radio waves into the monitoring area and detecting returning reflected radio waves from objects within the monitoring area and evaluating the returning reflected radio waves by the control and evaluation unit.

[0042] The radar sensor or radar device comprises the radar transmitter and the radar receiver for transmitting a radar signal into the surveillance area and receiving it from there. The radar transmitter and radar receiver are preferably designed together as a transceiver. The control and evaluation unit evaluates the received signal from the radar receiver to determine object properties. Preferably, a distance is measured from the signal propagation time of the radar signal. Other examples of object properties include speed or the mere determination of the presence or absence of objects in the first surveillance area.

[0043] Radar surveillance is well-known and used in many fields of application. Various principles are known for measuring the distance to a detected object, such as pulse radar, continuous wave radar, or FMCW (Frequency-Modulated Continuous Wave) radar. Direct measurement of speed using the Doppler effect is also a typical radar application.

[0044] Radar penetrates many materials and is therefore relatively robust. This also applies to outdoor weather conditions such as fog, rain, or snow.

[0045] The invention will be explained below with reference to further advantages and features, using exemplary embodiments, with reference to the accompanying drawings. The figures of the drawing show: Fig. 1 and Fig. 2 a system with at least one sensor for monitoring several protection areas.

[0046] In the following figures, identical parts are provided with identical reference numerals.

[0047] Fig. 1 shows a system 1 with at least one sensor 2 for monitoring a plurality of protection areas SB1, SB2, SB3, SB4 for violation by at least one object 3 and with a controller 4 for controlling a system 5 to be protected with a mechanically movable part 6, for example a robot 6 with the sensor 2 for at least surface monitoring of the protection areas SB1, SB2, SB3, SB4 with a control and evaluation unit 7 for evaluating the received signals of the sensor 2 in order to determine which of the protection areas SB1, SB2, SB3, SB4 is violated by the object 3, hereinafter referred to as protection area violation, and which protection area the object 3 has left, hereinafter referred to as protection area release, with the controller 4 for generating and outputting a switching signal which is a release signal for releasing the system operation.

[0048] The mechanically movable part 6 can be, for example, a driven mechanism, in particular a robot 6, a robot part, a movable machine part, or the like. An application with a robot 6 is described below, for example.

[0049] The controller 4 is designed to output the release signal when the controller 4 detects a predetermined sequence of events, wherein the events consist of protection area violations and protection area releases of the protection areas SB1, SB2, SB3, SB4 and each event is either a protection area violation or a protection area release.

[0050] The robot 6 has at least a first work area AB1 and a second work area AB2, wherein the robot 6 is located either in the first work area AB1 or in the second work area AB2, wherein the first work area AB1 is assigned a first protection area SB1 and a second protection area SB2, wherein the first protection area SB1 borders on the first work area AB1 and the second protection area SB2 borders on the first protection area SB1, wherein the first protection area SB1 can only be reached via the second protection area SB2, wherein the second work area AB2 is assigned a third protection area SB3 and a fourth protection area SB4, wherein the third protection area SB3 borders on the second work area AB2 and the fourth protection area SB4 borders on the third protection area SB3, wherein the third protection area SB3 can only be reached via the fourth protection area SB4.

[0051] The first work area AB1, the second work area AB2, the first protection area SB1, and the third protection area SB3 are secured against access at the sides by a barrier 11. The barrier 11 can be a fence or similar.

[0052] Furthermore, a conveying device 12 is provided for supplying material or goods to the robot. The conveying device can be, for example, a conveyor belt or similar.

[0053] The controller 4 is designed to start the robot 6 when an object 3 has left the first protection area SB1 and then the second protection area SB2, whereby a protection area release exists in the first protection area SB1 and then in the second protection area SB2, or an object 3 has left the third protection area SB3 and then the fourth protection area SB4, whereby a protection area release exists in the third protection area SB3 and then in the fourth protection area SB4, wherein when the robot 6 is active in the first working area AB1, in the event of protection area violations in the fourth protection area SB4, the controller 4 is designed to switch the robot 6 into a safe working mode and in the event of protection area violations in the second protection area SB2, the controller 4 is designed to stop the robot 6,Wherein, when the robot 6 is active in the second working area AB2, in the event of protection area violations in the second protection area SB2, the controller 4 is designed to switch the robot 6 into a safe working mode, and in the event of protection area violations in the fourth protection area SB4, the controller 4 is designed to stop the robot 6.

[0054] Robot 6 is not stopped if workpiece 8 is picked up or placed in the work area in which robot 6 is not currently working. If robot 6 is working in the first work area AB1, workpiece 8 can be picked up or placed in the second work area AB2. If robot 6 is working in the second work area AB2, workpiece 8 can be picked up or placed in the first work area AB1. This offers the advantage of increased productivity.

[0055] For this purpose, the area in front of robot 6—for example, a loading robot with two loading stations—is divided into two work areas AB1, AB2, for example, the left and right work areas or the first work area AB1 and the second work area AB2. Two protective fields SB1, SB2, SB3, SB4 are assigned to each of the two work areas AB1, AB2, so that a total of four protective areas SB1, SB2, SB3, SB4, or four protective fields, are monitored simultaneously.

[0056] In the first protection area SB1 and the second protection area SB2 as well as in the third protection area SB3 and the fourth protection area SB4, an independent sequence monitoring is implemented in which the entry and exit sequence is monitored.

[0057] An object 3 or a person 10 must first enter the second protection area SB2 and then the first protection area SB1 in order to be able to legally reach the first work area AB1. If the first protection area SB1 is entered without first entering the second protection area SB2, the robot 6 is stopped immediately.

[0058] Likewise, an object 3 or a person 10 must first enter the fourth protection zone SB4 and then the third protection zone SB3 in order to be legally able to reach the second work area AB2. If the third protection zone SB3 is entered without first entering the fourth protection zone SB4, the robot 6 is stopped immediately.

[0059] This detects a stepping behind, where a person 10 could enter directly into the danger zone, i.e. the first work area AB1 or the second work area AB2.

[0060] However, in the event of a permissible entry into the first protection area SB1 or the third protection area SB3, i.e., in the event of a previously described entry via the second protection area SB2 and the fourth protection area SB4, a stop of robot 6 is not always initiated. For example, if robot 6 is working in the second work area AB2, a permissible entry into the first protection area SB1 does not initiate a stop of robot 6, since person 10 is in a safe area in the first protection area SB1. Sequence monitoring remains active to detect stepping behind.

[0061] Thus, a workpiece can be picked up or placed in the first work area AB1 without stopping the robot 6. To ensure safety when the person 10 comes close to the robot 6, the robot 6 is reduced in speed or switched to collaborative operation, for example, when the second protection area SB2 is interrupted.

[0062] Thus, a workpiece can also be picked up or deposited in the second work area AB2 without stopping the robot 6. To ensure safety when the person 10 comes close to the robot 6, the robot 6 is, for example, reduced in speed or switched to collaborative operation when the fourth protection area SB4 is interrupted.

[0063] The advantage is that the robot 6 can continue to work productively and at the same time a person 10 can pick up or put down the other workpiece 8.

[0064] The protective zones SB1, SB2, SB3, SB4 or protective fields can, for example, have any shape or be configured with any shape. For example, parts of the protective zones SB1, SB2, SB3, SB4 or protective fields can have straight, curved, circular, and / or elliptical shapes.

[0065] According to Fig. 2, the robot 6 is a robot 6 for loading pallets 9, wherein a pallet 9 is present in the first work area AB1 and / or in the second work area AB2.

[0066] According to the further development, the robot 6 is not stopped if a pallet 9 is picked up or placed in the work area in which the robot is not currently working. If the robot is working in the first work area AB1, a pallet 9 can be picked up or placed in the second work area AB2. If the robot 6 is working in the second work area AB2, a pallet 9 can be picked up or placed in the first work area. This offers the advantage of increased productivity in the automated loading of pallets 9.

[0067] For example, the controller 4 is designed to generate the stop signal if a protection area SB1, SB2, SB3, SB4 is violated and the predetermined sequence has not been completed.

[0068] For example, the controller 4 has a timer so that the controller 4 can monitor whether successive events, i.e., successive protected area violations or successive protected area releases, occur within specific time windows. The timers are tuned, for example, to the movement speed of a person 10 as object 3.

[0069] For example, sensor 2 is a laser scanner. A laser scanner is an optoelectronic sensor, where the transmitter is a light transmitter and the receiver is a light receiver for contactless scanning of the monitoring area with the protection zones SB1, SB2, SB3, SB4 by transmitting light beams into the monitoring area and detecting returning reflected light beams from objects 3 within the monitoring area, and evaluating the returning reflected light beams by the control and evaluation unit 7.

[0070] For example, the laser scanner is a time-of-flight sensor, i.e., a laser scanner based on time-of-flight analysis, or a time-of-flight camera. In particular, the laser scanner is a safety laser scanner.

[0071] For example, the sensor is a 3D camera for three-dimensional detection of the protected areas SB1, SB2, SB3, and SB4. For example, the sensor is a radar sensor. Reference symbol: 1 system 2 sensors SB1 first protection area SB2 second protection area SB3 third protection area SB4 fourth protection area 3 Object 4 Control 5 Appendix 6 mechanically moving part or robot 7 Control and evaluation unit AB1 first work area AB2 second work area 8 Processing material 9 pallets 10 people 11 Barrier 12 Conveyor device

Claims

[1] System (1) with at least one sensor (2) for monitoring several protection areas (SB1, SB2, SB3, SB4) for violation by at least one object (3) and with a control (4) for controlling a system to be protected (5) with a mechanically movable part (6), with the sensor (2) for at least area monitoring of the protection areas (SB1, SB2, SB3, SB4) with a control and evaluation unit (7) for evaluating the received signals of the sensor (2) in order to determine which of the protection areas (SB1, SB2, SB3, SB4) is violated by the object (3), hereinafter referred to as protection area violation, and which protection area (SB1, SB2, SB3, SB4) the object (3) has left, hereinafter referred to as protection area release, with the controller (4) for generating and outputting a switching signal which is an enable signal for enabling the system operation, wherein the controller (4) is designed to output the release signal when the controller (4) detects a predetermined sequence of events, wherein the events consist of protection area violations and protection area releases of the protection areas (SB1, SB2, SB3, SB4) and each event is either a protection area violation or a protection area release, wherein the mechanically movable part has a first working area (AB1) and a second working area (AB2), wherein the mechanically movable part (6) is located either in the first working area (AB1) or in the second working area (AB2), wherein a first protection area (SB1) and a second protection area (SB2) are assigned to the first working area (AB1), wherein the first protection area (SB1) is adjacent to the first working area (AB1) and the second protection area (SB2) is adjacent to the first protection area (SB1), wherein the first protection area (SB1) is only accessible via the second protection area (SB2), wherein a third protection area (SB3) and a fourth protection area (SB4) are assigned to the second working area (AB2), wherein the third protection area (SB3) is adjacent to the second working area (AB2) and the fourth protection area (SB4) is adjacent to the third protection area (SB3), wherein the third protection area (SB3) is only accessible via the fourth protection area (SB4), wherein the controller (4) is designed to start the mechanically movable part (6) when an object (3) has left the first protection area (SB1) and then the second protection area (SB2), whereby a protection area release is present in the first protection area (SB1) and subsequently in the second protection area (SB2) or an object (3) has left the third protection area (SB3) and then the fourth protection area (SB4), whereby a protection area release exists in the third protection area (SB3) and then in the fourth protection area (SB4), wherein if the mechanically movable part (6) is active in the first working area (AB1) in the case of protection area violations in the fourth protection area (SB4), the control (4) is designed to switch the mechanically movable part (6) into a safe working mode and in the event of protection area violations in the second protection area (SB2), the control system (4) is designed to stop the mechanically movable part (6), wherein when the mechanically movable part (6) is active in the second working area (AB2), in the event of protection area violations in the second protection area (SB2), the control system (4) is designed to switch the mechanically movable part (6) into a safe working mode and in the event of protection zone violations in the fourth protection zone (SB4), the control system (4) is designed to stop the mechanically movable part (6). [2] System (1) according to claim 1, characterized by that the mechanically movable part (6) is a mechanically movable part (6) for loading pallets (9), wherein a pallet (9) is present in each case in the first working area (AB1) and / or in the second working area (AB2). [3] System (1) according to one of the preceding claims, characterized by that the controller (4) is designed to generate the stop signal if a protection area (SB1, SB2, SB3, SB4) is violated and the predetermined sequence has not been completed. [4] System (1) according to one of the preceding claims, characterized by that the controller (4) has a timer so that the controller (4) can monitor whether successive events occur within certain time windows. [5] System (1) according to one of the preceding claims, characterized by that the sensor (2) is a laser scanner. [6] System (1) according to one of the preceding claims, characterized by that the sensor (2) is a 3D camera for three-dimensional detection of the protection areas. [7] System (1) according to one of the preceding claims, characterized by that the sensor (2) is a radar sensor. [8] Method with at least one sensor (2) for monitoring several protection areas (SB1, SB2, SB3, SB4) for violation by at least one object (3) and with a control (4) for controlling a system to be protected (5) with a mechanically movable part (6), with the sensor (2) for at least area monitoring of the protection areas (SB1, SB2, SB3, SB4) with a control and evaluation unit (7) for evaluating the received signals of the sensor (2) in order to determine which of the protection areas (SB1, SB2, SB3, SB4) is violated by the object (3), hereinafter referred to as protection area violation, and which protection area (SB1, SB2, SB3, SB4) the object (3) has left, hereinafter referred to as protection area release, with the controller (4) for generating and outputting a switching signal which is an enable signal for enabling the system operation, wherein the controller (4) is designed to output the release signal when the controller (4) detects a predetermined sequence of events, wherein the events consist of protection area violations and protection area releases of the protection areas (SB1, SB2, SB3, SB4) and each event is either a protection area violation or a protection area release, wherein the mechanically movable part (6) has a first working area (AB1) and a second working area (AB2), wherein the mechanically movable part (6) is located either in the first working area (AB1) or in the second working area (AB2), wherein a first protection area (SB1) and a second protection area (SB2) are assigned to the first working area (AB1), wherein the first protection area (SB1) is adjacent to the first working area (AB1) and the second protection area (SB2) is adjacent to the first protection area (SB1), wherein the first protection area (SB1) is only accessible via the second protection area (SB2), wherein a third protection area (SB3) and a fourth protection area (SB4) are assigned to the second working area (AB2), wherein the third protection area (SB3) is adjacent to the second working area (AB2) and the fourth protection area (SB4) is adjacent to the third protection area (SB3), wherein the third protection area (SB3) is only accessible via the fourth protection area (SB4), wherein the mechanically movable part (6) is started when an object (3) has left the first protection area (SB1) and then the second protection area (SB2), whereby a protection area release is present in the first protection area (SB1) and subsequently in the second protection area (SB2) or an object has left the third protection area (SB3) and then the fourth protection area (SB4), whereby a protection area release exists in the third protection area (SB3) and then in the fourth protection area (SB4), wherein if the mechanically movable part (6) is active in the first working area (AB1) in the event of protection area violations in the fourth protection area (SB4), the mechanically movable part (6) is switched by the control (4) to a safe working mode and in the event of protection zone violations in the second protection zone (SB2), the mechanically movable part (6) is stopped by the control system (4), Wherein, when the mechanically movable part (6) is active in the second working area (AB2), in the event of protection area violations in the second protection area (SB2), the mechanically movable part (6) is switched into a safe working mode by the control system (4) and in the event of protection zone violations in the fourth protection zone (SB4), the mechanically movable part (6) is stopped by the control system (4).

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