System and method for controlling a rotary milking parlor device, computer program and non-volatile data carrier - Patents.com

Abstract

At least one drive unit (241, 242, 243, 244, 245) moves a rotating platform (130) of the rotary milking parlor apparatus in at least a first rotational direction (RF, RB) about a rotation point (P). Each drive unit comprises first and second drive motors arranged to engage a drive rail (230) of the rotating platform (130) and act on respective sides of the drive rail (230) to cause the rotating platform (130) to effect said movement. Each of the first and second drive motors generates a respective pace signal (p11, p12; p21, p22; p31, p32; p41, p42; p51, p52) indicative of the rotational speed of that drive motor. The control unit (220) receives pace signals (p11, p12; p21, p22; p31, p32; p41, p42; p51, p52) from each of the first and second drive motors of each drive unit. The control unit (220) compares the pace signal (p41) from the first drive motor with the pace signal (p42) from the second drive motor from each drive unit (241, 242, 243, 244, 245) to establish a respective difference in the rotational speeds of the drive units. If the difference exceeds a threshold, the control unit (220) triggers an alarm (A).

Description

[Technical field]

[0001] The present invention relates generally to a solution in which an animal is placed on a rotating platform while being milked. In particular, the present invention relates to a system for controlling a rotating platform of a rotary milking parlour apparatus and to a method implemented in such a system. The present invention also relates to a corresponding computer program and to a non-volatile data carrier storing such a computer program. [Background technology]

[0002] Today's automatic milking machines are very complex installations. In particular, the rotary milking parlor installation is one such example: here, a very heavy platform with a large number of animals rotates while the milker milks the animals on it. To rotate the platform, powerful electric motors are required. These motors must also be controllable with a very high precision, for example to adjust the rotation speed based on the milking characteristics of the animal currently on the platform. Furthermore, in case of an accident or breakdown, it must be possible to instantly stop and / or reverse the rotation of the platform.

[0003] Typically, one or more friction drive wheels are positioned below the platform and act perpendicularly to rotate the platform. For desired control, an integrated braking system may also be used, as described, for example, in U.S. Patent Application Publication No. 2016 / 0278340.

[0004] Applicant has discovered that efficiency and reliability of the system can be improved if the drive mechanism can be organized into one or more drive units disposed beneath the rotating platform to rotate the rotating platform, each drive unit including first and second drive motors that cooperate with one another, where the first drive motor is disposed to engage and act on one side of the drive rail of the platform, and the second drive motor is disposed to engage and act on the opposite side of the drive rail, and the two motors are continuously pushed toward one another to minimize slippage relative to the drive rail.

[0005] However, if one of the drive motors of a particular drive unit were to accidentally stop, there is a significant risk that friction between this stationary drive motor and the drive motors that are still running could push the drive rail up to such an extent that the platform would derail, which of course could lead to costly and dangerous consequences. Summary of the Invention

[0006] It is therefore an object of the present invention to provide a design which avoids the above problems. It is also an object of the present invention to provide early notification of a malfunctioning platform drive mechanism.

[0007] According to one aspect of the invention, the object is achieved by a system for controlling a rotary milking parlor apparatus, the rotary milking parlor apparatus comprising a rotating platform with a plurality of compartments, each of the plurality of compartments being configured to house a respective animal during milking. The system also comprises at least one drive unit and a control unit configured to control the operation of the at least one drive unit. The at least one drive unit is configured to move the rotating platform in at least a first rotational direction about a rotation point. Each of the at least one drive unit then comprises a first and a second drive motor arranged to engage with a drive rail of the rotating platform and act on a respective side of the drive rail such that the rotating platform performs said movement. Each of the first and second drive motors is configured to generate a respective pace signal indicative of a rotational speed of said drive motor. The control unit is configured to receive the pace signal from each of the first and second drive motors of each of the at least one drive unit. The control unit is further configured to compare the pace signal from the first drive motor with the pace signal from the second drive motor from each of the at least one drive unit to establish a respective difference in rotational speed. If the difference exceeds a threshold value, the control unit is configured to trigger an alarm. Depending on the current state of the system, the alarm may have different consequences. As a first measure, in case of an alarm, it is usually appropriate to at least temporarily stop the platform. However, in many cases, operation of the platform can continue after the alarm if appropriate measures are taken in response to the alarm.

[0008] The above system is advantageous because it not only detects stationary drive motors but also identifies malfunctioning drive motors whose rotational speed deviates excessively from their drive unit counterparts, thus significantly reducing the overall risk of the platform derailing.

[0009] According to one embodiment of this aspect of the invention, the control unit is further configured to, in response to the alarm, send a control signal to each drive unit whose pace signal triggered the alarm. The control signal is configured to disengage that drive unit from the drive rail. Thus, if the system includes at least one drive unit that is still functioning, the system may continue to operate based on this / these drive units. Naturally, this is desirable from a practical point of view, e.g., considering system uptime.

[0010] According to another embodiment of this aspect of the invention, each drive unit includes an actuator configured to disengage the drive unit from the drive rail by disengaging the first drive wheel from the second drive wheel in response to a control signal. Preferably, the actuator includes a pneumatic cylinder, a hydraulic cylinder, and / or an electric linear motor arranged to disengage the first and second drive wheels from one another, where the first drive wheel is disposed on a first side of the drive rail and is operated by a first drive motor in the drive unit, and the second drive wheel is disposed on a second side of the drive rail and is operated by a second drive motor in the drive unit. This makes disengagement of a malfunctioning drive unit very simple.

[0011] It is also advantageous if each drive unit has a sensor configured to check, in response to the control signal, whether the first drive wheel has been properly disengaged from the second drive wheel. If this is found to be the case, the sensor is configured to send a return signal to the control unit. The return signal confirms successful disengagement of the drive unit from the drive rail. As a result, the control unit is informed as to how the drive unit in question may affect the continued operation of the rotating platform.

[0012] According to yet another embodiment of this aspect of the invention, each drive unit includes at least one clamping member configured to, in an engaged mode, press a first drive wheel against a first side of the drive rail and a second drive wheel against a second side of the drive rail, such that sufficient contact between the drive wheels and the drive rail is maintained even if the drive rail is slightly uneven. Moreover, it is simple to release the clamping member in conjunction with disengagement via the actuator described above.

[0013] According to a further embodiment of this aspect of the invention, each drive unit includes an indicator-sensor arrangement configured to generate a pace signal indicative of the rotational speed of the first and second drive motors, respectively. The indicator-sensor arrangement includes first and second toothed metal collars. The first toothed metal collar is mechanically coupled to the first drive motor, and a first inductive sensor is configured to detect movement of the first toothed metal collar to generate the first pace signal. The second toothed metal collar is mechanically coupled to the second drive motor, and a second inductive sensor is configured to detect movement of the second toothed metal collar to generate the second pace signal. This provides reliable monitoring of the rotational speed of the drive motors, as the design is resistant to both dirt and mechanical influences.

[0014] Preferably, the first toothed metal collar is arranged to rotate with the first drive wheel and the second toothed metal collar is arranged to rotate with the second drive wheel, so that the pace signal is directly linked to the operation of the drive motor on the drive rail.

[0015] According to another aspect of the invention, the object is achieved by a method of controlling a rotary milking parlor apparatus, the rotary milking parlor apparatus comprising a rotating platform with a plurality of compartments, each of the plurality of compartments configured to house a respective animal during milking. It is further envisaged that the system comprises at least one drive unit configured to move the rotating platform in at least a first rotational direction about a rotation point. The method comprises controlling operation of the at least one drive unit. It is further envisaged that each of the at least one drive unit comprises first and second drive motors arranged to engage a drive rail of the rotating platform and act on respective sides of the drive rail to cause the rotating platform to perform said movement. Each of the first and second drive motors is configured to generate a respective pace signal indicative of a rotational speed of said drive motor. The method further includes receiving a pace signal from each of the first and second drive motors in each drive unit, comparing the pace signal from the first drive motor with the pace signal from the second drive motor from each drive unit to establish a respective difference in rotational speeds in each of the at least one drive unit, and triggering an alarm when the difference exceeds a threshold value. Advantages of this method, and preferred embodiments thereof, will be apparent from the above discussion of the system.

[0016] According to a further aspect of the invention the object is achieved by a computer program loadable onto a non-volatile data carrier communicatively connected to a processing unit, the computer program comprising software for carrying out the above method when the program is run on the processing unit.

[0017] According to another aspect of the invention, the object is achieved by a non-volatile data carrier comprising a computer program as described above.

[0018] Further advantages, beneficial features and applications of the present invention will become apparent from the following description and the dependent claims. [Brief description of the drawings]

[0019] The invention will now be explained in more detail by means of preferred embodiments disclosed as examples and with reference to the accompanying drawings, in which:

[0020] [Figure 1] 1 illustrates a rotating platform of a rotary milking parlor apparatus according to one embodiment of the present invention; [Diagram 2] 1 illustrates a system for controlling a rotating platform according to one embodiment of the present invention. [Figure 3a] 1 shows a schematic diagram of a drive unit according to an embodiment of the present invention; [Figure 3b] 1 shows a schematic diagram of a drive unit according to an embodiment of the present invention; [Figure 4] 1 shows a perspective view of a drive according to an embodiment of the present invention; [Figure 5a] 4 illustrates diagrammatically how a drive unit is disengaged according to one embodiment of the present invention; [Figure 5b] 4 illustrates diagrammatically how a drive unit is disengaged according to one embodiment of the present invention; [Figure 6] 1 illustrates a flow chart of a general method according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In Fig. 1, a rotating platform 130 is shown forming part of a rotary milking parlour arrangement. In this example, the rotating platform 130 has 18 milking compartments S. However, of course, a greater or lesser number of compartments S is conceivable according to the invention. Nevertheless, each compartment S is adapted to accommodate a respective animal while being milked by the milking machine.

[0022] The system according to the present invention includes at least one drive unit and control unit 220. Figure 1 shows five drive units, namely 241, 242, 243, 244, and 245, respectively, which are configured to move the rotating platform 130 in at least a first direction of rotation RF about a rotation point P. Depending on the size of the rotating platform 130, the number of drive units can be anywhere from 1 to 12.

[0023] 3a and 3b show schematic diagrams of a drive unit 244 according to an embodiment of the present invention. FIG. 3a shows the operation of the drive unit 244, in which the rotating platform 130 is moved in a first direction RF, e.g., forward. FIG. 3b shows the operation of the drive unit 244, in which the rotating platform 130 is moved in a second direction RB, e.g., backward. Each drive unit includes first and second drive motors 341 and 342 arranged to engage with a drive rail 230 of the rotating platform 130, which is preferably arranged below the rotating platform 130 and follows the circular contour of the rotating platform 130. The drive units act on each side of the drive rail 230 to cause the rotating platform 130 to perform its movement. Each of the first and second drive motors 341 and 342 of each drive unit 241, 242, 243, 244 and 245 is configured to generate respective pace signals p11, p12; p21, p22; p31, p32; p41, p42 and p51, p52 indicative of the rotational speed of that drive motor.

[0024] The control unit 220 is configured to control the operation of the drive units 241, 242, 243, 244 and 245. Among other things, this means that the control unit 220 is configured to receive pace signals p11, p12; p21, p22; p31, p32; p41, p42 and p51, p52 from each of the first and second drive motors 341 and 342 of each drive unit 241, 242, 243, 244 and 245. The control unit 220 is further configured to compare the pace signal p41 from the first drive motor 341 with the pace signal p42 from the second drive motor 342 from each drive unit 241, 242, 243, 244 and 245 to establish a respective difference in rotational speeds in each of said at least one drive unit. If the difference exceeds a threshold value, the control unit 220 is configured to trigger an alarm A. The alarm A may be expressed in the form of an acoustic and / or optical signal adapted to alert an operator. Alternatively or additionally, the alarm may also be expressed by a signal transmitted wirelessly or by cable to a monitoring unit, where it is configured to provide a notification to a user and / or to be registered in an automatic recording means, e.g. a data log.

[0025] In response to alarm A, the control unit 220 is preferably configured to stop the platform 130, at least temporarily, until steps are taken to overcome the problem that caused alarm A to be generated. In response to alarm A, the control unit 220 is preferably further configured to send a control signal to each drive unit whose pace signal triggered alarm A. Thus, given that it is pace signals p41 and p42 from drive unit 244 that triggered the alarm, the control unit 220 sends a control signal C4 to this drive unit 244. The control signal C4 is configured to disengage the drive unit 244 from the drive rail 230.

[0026] 4, the drive unit 244 may include, for example, an actuator 410 that is configured to, in response to a control signal C4, disengage the drive unit 244 from the drive rail 230 by separating the first drive wheel 351 from the second drive wheel 352. The actuator 410, in turn, may include a pneumatic cylinder, a hydraulic cylinder, and / or an electric linear motor arranged to separate the first and second drive wheels 351 and 352 from one another.

[0027] A first drive wheel 351 is disposed on a first side of the drive rail 230, e.g., on the inside of the circular loop formed by the drive rail 230. The first drive wheel 351 is operated by a first drive motor 341 in the drive unit 244. A second drive wheel 352 is disposed on a second side of the drive rail 230, e.g., on the outside of the circular loop, and is operated by a second drive motor 342 in the drive unit 244.

[0028] Preferably, the drive unit 244 includes at least one clamp member, which in an engagement mode presses the first drive wheel 351 against a first side of the drive rail 230 and the second drive wheel 352 against a second side of the drive rail 230. The embodiment of the invention shown in FIG. 4 has two clamp members 421 and 422, respectively, which can be represented by elastic elements such as helical springs and / or leaf springs. Thus, in practice, whenever the actuator 410 is deactivated, the clamp members 421 and 422 press the drive wheels 351 and 352 towards the drive rail 230, so that the drive wheels 351 and 352 can engage with the drive wheels and rotate the platform 130. FIGS. 5a and 5b show this function, where the actuation of the actuator 410 results in the entire motor and drive wheel arrangements 341 / 351 and 342 / 352, respectively, being pivoted away from each other by rotation about the axis R.

[0029] According to one embodiment of the present invention, the drive unit 244 includes at least one sensor configured to check whether the first drive wheel 351 has been properly decoupled from the second drive wheel 352 in response to the control signal C4. If it is found that the first drive wheel 351 has indeed been properly decoupled from the second drive wheel 352, the at least one sensor is configured to send a return signal (not shown) to the control unit 220. The return signal confirms the successful disengagement of the drive unit 244 from the drive rail 230. This informs the control unit 220 as to what extent the drive unit 244 may affect the continued operation of the rotating platform 130. For example, if a system includes a relatively large number of drive units, especially if the drive units involved are not adjacent to each other, it may be possible to disengage one or two of these drive units without significantly affecting the overall functioning of the system. However, if the original number of drive units in the system is relatively small, for example less than four, it is usually not possible to continue operating the rotating platform 130 with fewer than all drive units active. That is, in addition to propelling the rotating platform 130, the drive units are also preferably arranged to maintain stable rotation about a rotation point P. If the distribution of active drive units becomes too unbalanced, it may become difficult or impossible to ensure such stable rotation about a fixed rotation point.

[0030] Of course, if disengagement of the malfunctioning drive unit fails, the rotating platform 130 cannot continue to operate. Thus, if the control unit 220 does not receive a return signal within a certain interval after sending the control signal C4, the control unit 220 is configured to stop the rotating platform 130.

[0031] 4, according to one embodiment of the invention, each drive unit 244 has an indicator-sensor device configured to generate pace signals p41 and p42 indicative of the rotational speeds of first and second drive motors 341 and 342, respectively, within the drive unit 244. The indicator-sensor devices include first and second toothed metal collars 461 and 462, respectively.

[0032] The first toothed metal collar 461 is mechanically coupled to the first drive motor 341, for example by being arranged to rotate with the first drive wheel 351. The first inductive sensor 471 is configured to detect the movement of the first toothed metal collar 461 and generate a first pace signal p41 in response thereto. Similarly, the second toothed metal collar 462 is mechanically coupled to the second drive motor 342, for example by being arranged to rotate with the second drive wheel 352. The second inductive sensor 472 is configured to detect the movement of the second toothed metal collar 462 and generate a second pace signal p42. The first and second toothed metal collars 461 and 462 are preferably designed such that the relationship between the tooth width and the tooth spacing is in the range of 50:50 to 25:75, preferably about 1 / 3 to 2 / 3.

[0033] It is generally advantageous if the control unit 220 is configured to carry out the above procedures automatically by executing a computer program 227. The control unit 220 may therefore comprise a memory unit 225, i.e. a non-volatile data carrier, which stores a computer program 227, the computer program 227 comprising software for causing a processing circuit in the form of at least one processor 223 in the central control unit 220 to carry out the aforementioned operations when the computer program 227 is made to run in the at least one processor 223.

[0034] To summarize, and with reference to the flow chart of FIG. 6, a general method according to the present invention for controlling a rotating platform of a rotary milking parlor will now be described.

[0035] In a first step 610, a pace signal is received from each drive motor of each drive unit, so for example if there are four drive units, a total of eight pace signals are received.

[0036] Next, in step 620, the pace signal from the first drive motor is compared to the pace signal from the second drive motor from each drive unit to establish a respective difference in the rotational speed of each drive unit.

[0037] In the following step 630 it is checked whether the difference exceeds a threshold value, and if so, continues with step 640. If not, the procedure returns to step 610.

[0038] In step 640, an alarm is triggered, indicating a functional problem with at least one of the drive units. Preferably, the alarm also specifies the drive unit that triggered the alarm.

[0039] In a preferred embodiment of the invention, step 650 follows step 640. In step 650, in response to the alarm, a control signal is sent to each drive unit which triggered the alarm, which control signal is configured to result in that drive unit being disengaged from the drive rail of the rotating platform, so that the rotary milking parlor can continue to operate, at least temporarily, for example while emptying the rotating platform of animals.

[0040] After step 640 or 650, the procedure returns to step 610.

[0041] All the process steps, and sub-sequences of steps, described with reference to FIG. 6 may be controlled using a programmed processor. Furthermore, although the embodiments of the invention described above with reference to the figures include a processor and a process executed on at least one processor, the invention therefore extends to a computer program, in particular a computer program on or in a carrier adapted for putting the invention into practice. The program may be in the form of source code, object code, code intermediate source and object code, e.g. partially compiled form, or any other form suitable for use in implementing the process according to the invention. The program may be part of an operating system or another application. The carrier may be any entity or device capable of executing a program. For example, the carrier may include a storage medium such as a flash memory, a ROM (read only memory), e.g. a DVD (digital video / versatile disc), a CD (compact disc), or a semiconductor ROM, an EPROM (erasable programmable read only memory), an EEPROM (electrically erasable programmable read only memory), or a magnetic recording medium, e.g. a floppy disk or a hard disk. Furthermore, the carrier may be a transmissible carrier, such as an electrical or optical signal, which may be transmitted via an electrical or optical cable, or by radio or other means. When the program is embodied in a signal which may be conveyed directly by a cable or other device or means, the carrier may be constituted by such a cable or device or means, or the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted for performing, or for use in the performance of, the relevant processes.

[0042] As used in this specification, the term "comprises / comprising" is used to describe the presence of stated features, integers, steps or components, but this term does not exclude the presence or addition of one or more additional features, integers, steps, components or groups thereof.

[0043] The invention is not limited to the embodiments described in the drawings but may be freely varied within the scope of the claims.

Claims

1. A system for controlling a rotary milking parlor apparatus, the rotary milking parlor apparatus comprising a rotating platform (130) with a plurality of compartments (S), each of the plurality of compartments (S) configured to house a respective animal during milking, the system comprising: at least one drive unit (241, 242, 243, 244, 245) configured to move said rotating platform (130) in at least a first rotational direction (RF, RB) about a rotation point (P); a control unit (220) configured to control the operation of the at least one drive unit (241, 242, 243, 244, 245); each of the at least one drive unit includes first and second drive motors (341, 342) arranged to engage a drive rail (230) of the rotating platform (130) and act on a respective side of the drive rail (230) to cause the rotating platform (130) to perform said movement, each of the first and second drive motors (341, 342) configured to generate a respective pace signal (p11, p12; p21, p22; p31, p32; p41, p42; p51, p52) indicative of a rotational speed of the respective drive motor, and the control unit (220) further receiving the pace signals (p11, p12; p21, p22; p31, p32; p41, p42; p51, p52) from the first and second drive motors (341, 342) of each of the at least one drive units (241, 242, 243, 244, 245); comparing the pace signal (p41) from the first drive motor (341) with the pace signal (p42) from the second drive motor (342) from each of the at least one drive unit (241, 242, 243, 244, 245) to establish a respective difference in the rotational speeds of each of the at least one drive unit, and if the difference exceeds a threshold value, A system configured to trigger an alarm (A).

2. 2. The system of claim 1, wherein the control unit (220) is further configured to, in response to the alarm (A), send a control signal (C4) to each of the one or more drive units (244) whose pace signals (p41, p42) triggered the alarm (A), the control signal (C4) configured to disengage the drive units (244) from the drive rail (230).

3. each of the drive units (241, 242, 243, 244, 245) includes an actuator (410), the actuator (410) being configured to, in response to the control signal (C4), disengage the drive unit (244) from the drive rail (230) by separating a first drive wheel (351) from a second drive wheel (352); the first drive wheel (351) is disposed on a first side of the drive rail (230) and is operated by a first drive motor (341) of the drive unit (244); 3. The system of claim 2, wherein the second drive wheel (352) is disposed on a second side of the drive rail (230) and is operated by a second drive motor (342) of the drive unit (244).

4. 4. The system of claim 3, comprising at least one of a pneumatic cylinder, a hydraulic cylinder, and an electric linear motor arranged to separate the actuator (410), the first and second drive wheels (351; 352) from one another.

5. 5. The system of claim 3 or 4, wherein each of the drive units (241, 242, 243, 244, 245) includes at least one clamp member (421, 422), configured to, in an engagement mode, force the first drive wheel (351) toward the first side of the drive rail (230) and force the second drive wheel (352) toward the second side of the drive rail (230).

6. Each of the drive units (241, 242, 243, 244, 245) further comprises at least one sensor, the at least one sensor being responsive to the control signal (C4) to: checking whether the first drive wheel (351) is properly decoupled from the second drive wheel (352); and if it is found that the first drive wheel (351) is properly decoupled from the second drive wheel (352), The system of any one of claims 3 to 5, configured to: send a return signal to the control unit (220), the return signal confirming successful disengagement of the drive units (241, 242, 243, 244, 245) from the drive rail (230).

7. Each of the drive units (241, 242, 243, 244, 245) includes an indicator-sensor device configured to generate the pace signal (p41, p42) indicative of the rotational speed of the first and second drive motors (341, 342) of the drive unit (244), respectively, the indicator-sensor device comprising: a first toothed metal collar (461) mechanically coupled to the first drive motor (341) and a first inductive sensor (471) configured to detect movement of the first toothed metal collar (461) to generate a first pace signal (p41); 7. The system of claim 1, further comprising: a second toothed metal collar (462) mechanically coupled to the second drive motor (342); and a second inductive sensor (472) configured to detect movement of the second toothed metal collar (462) and generate a second pace signal (p42).

8. the first toothed metal collar (461) is arranged to rotate with the first drive wheel (351); A system according to claim 7 when dependent on any one of claims 3 to 6, wherein the second toothed metal collar (462) is arranged to rotate together with the second drive wheel (352).

9. A method of controlling a rotary milking parlor apparatus, said rotary milking parlor apparatus comprising a rotating platform (130) with a plurality of compartments (S), each of said plurality of compartments (S) configured to house a respective animal during milking, a system comprising at least one drive unit (241, 242, 243, 244, 245) configured to move said rotating platform (130) in at least a first rotational direction (RF, RB) about a rotation point (P), said method comprising: controlling the operation of said at least one drive unit (241, 242, 243, 244, 245); wherein each of the at least one drive unit includes first and second drive motors (341, 342) arranged to engage a drive rail (230) of the rotating platform (130) and act on a respective side of the drive rail (230) to cause the rotating platform (130) to perform said movement, each of the first and second drive motors (341, 341) configured to generate a respective pace signal (p11, p12; p21, p22; p31, p32; p41, p42; p51, p52) indicative of a rotational speed of the drive motor, the method further comprising: receiving the pace signals (p11, p12; p21, p22; p31, p32; p41, p42; p51, p52) from each of the first and second drive motors (341, 342) of each of the at least one drive unit (241, 242, 243, 244, 245); comparing the pace signal (p41) from the first drive motor (341) with the pace signal (p42) from the second drive motor (342) from each of the at least one drive unit (241, 242, 243, 244, 245) to establish a respective difference in the rotational speeds of each of the at least one drive unit, and if the difference exceeds a threshold value, and triggering an alarm (A).

10. In response to the alarm (A), the method further comprises:

10. The method of claim 9, further comprising transmitting a control signal (C4) to each of the one or more drive units (244) that triggered the alarm (A), the control signal (C4) being configured to disengage the drive units (244) from the drive rail (230).

11. A computer program (227) loadable onto a non-volatile data carrier (225) communicatively connected to a processing unit (223), said computer program (227) comprising software for carrying out a method according to any one of claims 9 to 10 when said computer program (227) is executed on said processing unit (223).

12. A non-volatile data carrier (225) containing a computer program (227) according to claim 11.

Images