Control unit and method for operating a conveyor device

Abstract

The invention relates to a method for operating a conveyor, in particular an elevator, a crane, a continuous conveyor, etc., and to a control unit, wherein the conveyor comprises a drive unit (21) and a control unit (20) for controlling the drive unit, wherein the drive unit comprises at least two drives (43, 44), wherein the drives are controlled by a control device (22) of the control unit, wherein a rotary encoder (25, 38) of the control unit is in each case connected to a drive of a respectively assigned shaft of the drive unit of the conveyor and detects the rotation of the shaft, wherein an encoder device (26, 39) of the respective rotary encoder serves to transmit a rotation angle signal and / or a rotation speed signal to the control device for controlling the drive, wherein the control device determines the respective rotation speed of the shaft and compares it with a reference rotation speed, wherein the control device controls the drive in dependence on the comparison.

Description

[0001] The invention relates to a control unit for a conveying device, in particular a hoist, a crane, a continuous conveyor, etc., comprising a drive unit and a control unit for controlling the drive unit, and a method for operating a conveying device. The drive unit comprises at least two drives, which are controlled by a control device of the control unit. A rotary encoder of the control unit is connected to a shaft of the drive unit of the conveying device and records the rotation of the shaft, each shaft being assigned to a drive. A rotation angle signal and / or a rotation speed signal is transmitted to the control device by an encoder device of the respective rotary encoder for controlling the drives.

[0002] Such control units and methods are known in the prior art and are mainly used for recording the position and the rotation speed of a shaft. The rotary encoder of the control unit comprises at least one shaft, which can be coupled to the machine or is directly provided on a shaft of the machine. Furthermore, the rotary encoder comprises mechanical, optical or magnetic encoder devices or recording elements. For example, the encoder devices can form an incremental encoder or an absolute encoder. In a mechanical embodiment, the encoder devices can be switches or counters. The encoder devices can obtain signals of the rotation of the shaft, such as a rotation angle signal or a rotation speed angle. From these signals, the rotation angle position of the shaft or the rotation speed of the shaft can be determined by a control device of the control unit, to which the rotary encoder is connected by a signal line.

[0003] Furthermore, the rotary encoder is used in or on a conveying device, such as a hoist with a rope hoist, a crane, a boom, a crane, a winch, etc., and in or on a conveyor belt and is subjected to a high load during operation. Therefore, the housing of the rotary encoder is usually made of metal, so that the rotary encoder is relatively resilient to mechanical and thermal stresses. In order to transmit the signals of the encoder devices to the control device of the conveying device, the rotary encoder has a signal output device, if necessary, which pre-processes the signals for transmission to the control device, which is required, inter alia, for fiber optic cables.

[0004] Rotary encoders on the conveyor device are mainly used to obtain specific operating parameters of the conveyor device, such as the rotational speed of the rope drum or the motor or electric motor for driving the rope drum. Thus, conveyor devices are known, in which a drive unit is formed with a rope for lifting the bearing load, a rope drum, a motor and a transmission device which is switched between them. A rotary encoder can be provided on the shaft of the motor and / or on the shaft of the rope drum, which in each case transmits a rotational angle signal and / or a rotational speed signal to a control device of the conveyor device in order to control the assigned motor. Thus, the conveyor device usually has a plurality of such drives or motors, which means that a plurality of rotary encoders are installed in the hoist. The control device thus forms a control unit together with the rotary encoders, which regulates the drive unit depending on the bearing load. The control device receives information from the respective rotary encoder about the rotational speed of the shaft of the power transmission device driven by the motor or of the respective drive. For example, at a relatively large bearing load, the control device adjusts the rotational motor speed of the respective motor so that a certain speed or a rotational speed at the rope drum is not exceeded when lifting or lowering the bearing load. If the bearing load is relatively small, such as an empty container, the bearing load can be lifted at a higher speed, i.e. with a higher motor rotational speed. The respective motors are always adjusted independently of one another depending on the respective rotational speed. Thus, the adjustment of the drive unit by the control device always aims to adjust the performance of the drive unit to the bearing load so that the bearing load can be conveyed by the conveyor device or hoist as quickly as possible. In addition to this adjustment of the drives on the hoist, a control unit can also be provided on other conveyor devices, such as continuous conveyors or belt conveyors. In this case, too, a plurality of drives for transporting the load or working load are often used.

[0005] In the hoists known from the prior art, the control device is usually arranged in a control cabinet of the conveyor device and can be a programmable logic controller (PLC), which can be programmed by an external programming device, such as a standardized computer. In the programmable logic controller or rather the control device, a processing element is integrated, which processes the rotational angle signals and / or rotational speed signals from the rotary encoders of the conveyor device and converts them so that the drives can be controlled by the control device depending on the rotational speed. The disadvantage here is that the programmable logic controller always has to be programmed individually. This programming of the control device usually has to take into account the prevailing safety regulations, so that the thus implemented control device also has to be controlled individually for safety reasons. Furthermore, the conveyor speed is limited by the adjustment of the individual drives with the programmable logic controller or control device.

[0006] It is therefore the object of the present invention to propose a method for operating a conveyor device and a control unit as well as a conveyor device by each of which the conveyor device can be operated more efficiently.

[0007] The object of the present application is achieved by a method having the features of a method for operating a conveyor, in particular a hoist, a crane, a continuous conveyor, etc., a control unit having the features of a control unit for a conveyor, in particular a hoist, a crane, a continuous conveyor, etc., and a conveyor having the features of a conveyor, in particular a hoist, a crane, etc.

[0008] In the method for operating a conveyor, in particular a hoist, a crane, a continuous conveyor, etc., according to the present application, the conveyor comprises a drive unit and a control unit for controlling the drive unit, the drive unit comprising at least two drives, the drives being controlled by control means of the control unit, a rotary encoder of the control unit being connected to a shaft of the drive unit of the conveyor and recording the rotation of the shaft, the shafts being each assigned to a drive, the rotation angle signal and / or the rotation speed signal being transmitted to the control means by encoder means of the respective rotary encoder in order to control the drives, the control means determining the respective rotation speed of the shafts and comparing it to a reference rotation speed, the control means controlling the drives depending on the comparison.

[0009] In the method according to the present application, at least one rotary encoder is thus provided on each drive or power transmission device having one or more shafts, the rotary encoder being provided on at least one shaft, the rotary encoder being used to determine the rotation speed of the shaft of the power transmission device and thus of the drive. The respective rotary encoder transmits the rotation angle signal and / or the rotation speed signal of the encoder means of the rotary encoder to the control means. To this end, the rotary encoder can process the rotation angle signal and / or the rotation speed signal itself and can also transmit a rotation speed value or a value having rotation speed information to the control means. The control means can then determine the respective rotation speed of the shafts and thus of the individual drives. The control means further compare the respective rotation speeds of the shafts and the drives and compare them to a reference rotation speed. The control means can thus detect a rotation speed difference of each drive with respect to the reference rotation speed. The control means control the respective drives depending on the detected comparison of the rotation speed of the drives of the shafts to the reference rotation speed. All drives of the drive unit can thus be synchronized according to the reference rotation speed. A possible rotation speed difference between the drives is thus avoided, which can occur when each drive is individually adjusted according to the rotation speed of the assigned rotary encoder. Overall, a higher conveying speed can also be achieved since the drive having the lowest rotation speed within the drive unit no longer determines the maximum conveying speed. For example, the reference rotation speed can be positioned on the drive having the highest rotation speed, that is to say, the rotation speeds of the remaining drives are adjusted by the control means to the highest possible rotation speed.

[0010] Accordingly, the control device can determine the reference rotational speed from the rotational angle signal and / or the rotational speed signal of one of the rotary encoders, the control device being able to adjust each drive in accordance with the reference rotational speed. The control device can record all rotational speeds of the shafts or power transmission devices simultaneously by the respectively assigned rotary encoders and, for example, define the highest rotational speed as the reference rotational speed, in accordance with which the rotational speeds of the remaining drives are respectively adjusted. Accordingly, all drives can be operated with almost uniform synchronous rotational speeds. A possible slipping of the drive units between the drives, which can result in a loss of performance, can also be prevented.

[0011] Advantageously, the control device can determine the corresponding acceleration of the shafts and compare it to a reference acceleration, the control device being able to adjust each drive in accordance with the reference acceleration. The control device can determine or adjust the acceleration by means of the rotational angle signal and / or the rotational speed signal in combination with a time period. Accordingly, the acceleration of the corresponding shaft of the drive can also be adjusted in accordance with the reference acceleration. Also in this case, the control device can define or select the reference acceleration from one of the measured accelerations of the shafts. Adjusting the drives in accordance with the reference acceleration makes it possible to more precisely synchronize the rotational speeds of the drives or shafts.

[0012] It is particularly advantageous if the control device can record the load signals of the load sensors from the sensor devices assigned to the individual drives and compare them to a reference load, the control device being able to adjust each drive in accordance with the reference load. A load sensor can be assigned to each drive or power transmission device, which detects the operating load of the drive or the assigned shaft and transmits a load signal to the control device. In this case, the control device can compare the respective load signals to one another and correlate them to the reference load. One of the load signals can also be the reference load. The control device can then adjust all loads in accordance with the reference load, for example by adjusting the rotational speeds of the respective drives.

[0013] In the control device, range parameters for the rotational speeds, accelerations and / or loads can be stored; the reference rotational speed, the reference acceleration and / or the reference load can be limited by means of the range parameters. Accordingly, the control device no longer needs to query the rotational speeds, accelerations and / or loads detected by the rotary encoders and / or load sensors of the drives or power transmission devices as reference rotational speeds, reference accelerations and / or reference loads for adjusting the drives. For example, range parameters can be stored in the control device, so that the rotational speeds, accelerations and / or loads of all drives can be adjusted within the range of the range parameters during the operation of the conveyor device. However, in this case, the individual drives can be synchronized since the range parameters or the range can be selected close enough for the drives to be synchronized.

[0014] By means of the rotary encoders, load signals can be recorded by load sensors assigned to the drives, which are able to determine load-related variables from the rotary angle signals and / or the rotary speed signals and the load signals and to transmit them to the control device for controlling the device. In this way, the combination of the rotary angle signals and / or the rotary speed signals of the encoder devices of the rotary encoders and the load signals of the load sensors, which is usually intended to take place in the control device, can take place in the rotary encoders. Thus, each rotary encoder receives the load signals of the correspondingly assigned load sensors and processes these signals by means of data processing in combination with the rotary angle signals and / or the rotary speed signals of the respective rotary encoder to generate load-related variables, which can be transmitted to the control device. The load-related variables can be further processed by the control device directly for controlling the respective drive without the need for specific individual programming of the control device for combining the respective signals. The rotary encoders installed in the conveyor device can be standardized rotary encoders, which only require one-off control for safety reasons related to signal processing or programming. The programmable logic controller of the control device can thus be programmed with significantly less effort. The signal processing in the individual rotary encoders generally allows a faster processing speed of the control unit, since the control device no longer has to perform this signal processing. The load-related variables can also be transmitted as signals by the respective rotary encoders to the control device, which differ from the rotary angle signals and / or the rotary speed signals in that information directly related to the work load is contained in the signals.

[0015] The control device can limit the rotary speed of the drive or shut down the drive when the load is exceeded. Thus, it can be ensured at the conveyor device that for the work load to be conveyed, a maximum permissible rotary speed, for example a threshold rotary speed, is not exceeded. Thus, a work load that is too large for the conveyor device cannot be conveyed using the conveyor device.

[0016] By means of a plurality of load sensors each assigned to a drive, load signals of the work point, the rope load and / or the winding load can be recorded. For example, these load sensors can be arranged on the rope drum of the hoist or can even measure the winding speed, from which the winding load can be derived. Furthermore, load sensors can be used to measure load situations which involve mechanical interference, such as shaft breakage or movement of the hoist boom. Thus, a plurality of load sensors can be arranged on the hoist or conveyor device to measure various load situations.

[0017] Load plugs or load measuring units can be used as load sensors. For example, if the drive unit or drive has ropes, two load signals can be recorded for each rope in order to achieve redundancy of the load sensors.

[0018] It is particularly advantageous if the load signal is recorded by the load sensor assigned to the drive by a safety element of the respective rotary encoder, which is able to determine a load-dependent maximum threshold rotational speed from the rotational angle signal and / or the rotational speed signal and the load signal and to transmit them to the control device for controlling the drive. Since the respective threshold rotational speed is calculated by the safety element of the rotary encoder, the programming effort and the error-prone tendency of the control device are significantly reduced. The control device can then take the maximum threshold rotational speed value directly from the rotary encoder and further process this value for controlling the drive. Since the rotary encoder is able to process these signals, the control device no longer needs to be adjusted for specific types of rotational angle or rotational speed signals or load signals and no longer needs to be safety-certified, so that the effort for starting up the conveying device can be significantly reduced. Thus, each rotary encoder can be an independent rotary encoder system, which only needs a one-time safety check.

[0019] The safety element can determine a function of the threshold rotational speed from the rotational angle signal and / or the rotational speed signal and the load signal. For example, a mathematical adjustment function of the threshold rotational speed can be matched to the performance-specific curve of the electric motor of the drive. The threshold rotational speed can then be determined in an infinitely variable manner and in a way that is suitable for the possible maximum performance of the electric motor. This can advantageously increase the conveying speed of the drive or drive unit.

[0020] The safety element can correct the load signal of the load sensor while taking into account the acceleration of the work load at the conveying device. Thus, the safety element can take into account, for example, the acceleration of the rope and the acceleration of the work load when lifting or lowering the work load by the drive, the self-weight of the rope can be relevant for determining the threshold rotational speed. The safety element can also determine the net load and / or the total load. Furthermore, the safety element can be used to calculate the sum and the difference of the individual load values.

[0021] The safety element can determine the eccentricity of the work load or bearing load on the hoist from the load signal. For example, if a plurality of load sensors is provided or the drive unit has a plurality of ropes for lifting the bearing load, the load distribution on the ropes or load sensors can be determined. Depending on the type of bearing load, for example a container or different objects with a non-uniformly distributed load, a greater load can be measured at one rope opposite to another rope. The safety element can then take this load distribution into account and adjust the threshold rotational speed of the individual drives of the ropes depending on the maximum measured load.

[0022] The control device can transmit a status signal containing information about the type of operation of the drive to the safety element, which can take the status signal into account when determining the load-dependent threshold rotational speed. For example, the type of operation can be lifting or lowering the bearing load, exceeding the threshold load or overload, slack rope, empty run or rapid drive of the individual drives. For example, if the load from the rope weight is particularly low, the load-dependent threshold rotational speed can also be completely ignored during the empty run.

[0023] The safety element can determine lifting, lowering, overload, slack rope or empty run as the type of operation of the drive from the rotational angle signal and / or the rotational speed signal and / or the load signal and can transmit this information to the control device. In this way, the safety element can determine the type of operation itself by evaluating the respective signals and deriving the possible type of operation therefrom. For this purpose, certain numerical ranges or signal patterns can be stored in the safety element, which enable the type of operation to be determined by comparison. If the control device transmits the type of operation to the safety element, a plausibility comparison can be made in the safety element. If the results do not agree, the respective drive device or the entire drive unit can be switched off, for example, by the control device.

[0024] By means of a rotary encoder, a switching signal of an end switch of the sensor device can be recorded, which can determine the relative position of the drive load on the conveyor device from the switching signal, which the safety element can take into account when determining the load-dependent threshold rotational speed. For example, by means of the end switch, the relative position of the winch of the crane jib can be determined. It is thus also possible to determine that the working load or the bearing load moves at a lower threshold rotational speed in a safety-relevant region, for example, such as when the track is located below the crane. The end switch also allows the possible length of the rope at a specific position of the crane to be determined and taken into account when determining the threshold rotational speed.

[0025] The safety element can assign a maximum threshold load to each type of operation or relative position. With the respective maximum threshold load, the load-dependent threshold rotational speed associated therewith can be determined in turn. The maximum threshold load can be defined in particular with a view to safety and stored in the safety element for the respective type of operation or relative position. In this case, it can also be provided that, when the respective maximum threshold load is reached, the load signal of the load sensor is not taken into account.

[0026] It is particularly advantageous if the load signal is recorded by a counter of a rotary encoder, which is able to store the rotation angle signal and / or the rotation speed signal and the load signal within an operating period in order to determine a load-related damage value and to transmit it to a control element for controlling the drive. The counter can then store individual or all signals, load signals, rotation angle signals and / or rotation speed signals within an operating period and they can be added up. The counter element can detect a total load or a load collection corresponding to the load-related damage value. Thus, for example, each lifting of the bearing load leads to an increased fatigue of the components at the hoist, which must be inspected or replaced for safety reasons when a certain number of values or a total moving bearing load is reached.

[0027] The counter can determine a point in time at which the drive or other components have worn out from the stored signals. At this point, an inspection or repair is required, including the replacement of components if necessary. The counter can signal the point in time or the point in time itself and initiate a shutdown or a reduction of the operating performance of the drive or drive unit by transmitting the damage value to the control device.

[0028] The load signal can also be recorded by an evaluation element of the rotary encoder, which is able to determine the weight of the work load at the conveyor and transmit it to the control device from the load signal. Thus, the evaluation element can determine the net weight by means of the load signal of the evaluation element for weighing the work load or the bearing load. The use of load sensors, which are only used for weighing the bearing load and for determining the load on the components of the conveyor, is no longer necessary. Thus, the load sensors for weighing are no longer necessary.

[0029] It is also possible to connect a further rotary encoder of the control unit to a further shaft of the drive and to record the rotation of the further shaft, by means of which a rotation speed and / or load signal is recorded, which is able to determine a further load-related variable from the further rotation angle signal and / or the further rotation speed signal and the load signal and to transmit them to the control device for controlling the drive. The drive unit can comprise a plurality of rope drums, electric motors and transmission devices for transmitting individual work loads. The control device receives the latest load-related variable from the corresponding rotary encoder, which can be used by the control device for controlling the entire drive unit or individual motors and / or drives of the drive unit.

[0030] The control unit for a conveyor device, in particular a hoist, a crane, a continuous conveyor, etc., according to the invention comprises a control device and at least two rotary encoders, which can be connected to the shafts of the conveyor device in order to record the rotation of the respective shaft, each rotary encoder being assigned to a drive of the drive unit, the rotary encoders comprising encoder means for outputting a rotation angle signal and / or a rotation speed signal to the control device in order to control the drive unit, the respective rotation speed of the shafts being determinable by the control device and compared to a reference rotation speed, the drive device being controllable by the control device in accordance with the comparison. Details on the advantages of the control unit according to the invention are referred to the description of the advantages of the method according to the invention.

[0031] Advantageously, one of the plurality of rotary encoders can comprise the control device. In this case, the control unit only requires one control device integrated in one of the plurality of rotary encoders. The remaining rotary encoders can be directly connected to the rotary encoder comprising the control device. The rotation angle signals and / or rotation speed signals of the remaining rotary encoders can then be directly transmitted to the control device of one rotary encoder, which is able to further process the signals for controlling the drive unit or the individual drives without the control device having to be individually programmed in a specific manner to incorporate the respective signals. The rotary encoders installed in the conveyor device can be standardized rotary encoders, which only require a one-time check with regard to signal processing or programming for safety reasons. The programmable logic controller of the control device can be programmed with significantly less effort. The signal processing in the rotary encoders also allows for an overall faster processing speed of the control unit, since the control device no longer has to perform the signal processing. A load-related variable can also be transmitted as a signal by a load sensor to the control device of one rotary encoder, which differs from the rotation angle signal and / or the rotation speed signal in that the information related to the working load can be directly included in the signal. All rotary encoders of the control unit can be simply coupled to the control device via a field bus interface for exchanging data via the field bus. In general, the control device can also be arranged separately from the rotary encoders.

[0032] The rotary encoders can also comprise a switching output for exceeding or falling below a parameterizable load-related output value. The switching output can be equipped with a safety relay or a semiconductor relay. The parameterizable output value can be a rotation speed value, an excessively high or low rotation speed value, a rotation angle value or a rotation speed difference value.

[0033] The rotary encoders can be incremental encoders and / or absolute encoders. For example, if the rotary encoders are arranged on the drive or on the electric motor of the drive unit, an incremental encoder can be advantageously used. For example, if the rotary encoders are arranged on the rope drums of the drive unit, the incremental signals and / or the absolute signals can be advantageously further processed. The encoder device can output these signals in parallel to the rotary angle signal and / or the rotary speed signal or to a load-related variable. The absolute signal can be a signal which is referred to as a single-turn signal (reference to a single rotation of the shaft) or a multi-turn signal (reference to multiple rotations of the shaft). Furthermore, the rotary encoders can have a digital or an analog output for the absolute signal or the incremental signal. The analog output can be a power output or a voltage output.

[0034] The control unit can also comprise four or more rotary encoders. For example, the control unit can consist of two incremental encoders and two absolute encoders which are assigned to or connected with the two power transmission devices. However, if the conveying device is a continuous conveyor, such as a belt conveyor with multiple drives, the number of rotary encoders can be much greater.

[0035] Further advantageous embodiments of the control unit result from the description of the features of the dependent claims relating to a control unit for a conveying device, in particular a hoist, a crane, a continuous conveyor, etc.

[0036] The conveying device according to the application, in particular a hoist, a crane, etc., comprises a control unit according to the application and a drive unit with at least two electric motors, power transmission devices and two rope drums.

[0037] The application is described in more detail below with reference to the drawings.

[0038] Figure 1 is a schematic diagram of the configuration of a control unit according to the prior art;

[0039] Figure 2 is a schematic diagram of the configuration of a control unit.

[0040] Figure 3 is a simplified diagram of a drive unit.

[0041] Figure 1A control unit 10 according to the prior art is shown together with a drive unit 11, which has a drive not shown in the figure. The control unit 10 comprises a control device 12, a sensor device 13 with load sensors (not shown), a programming device 14 and a rotary encoder 15. A further rotary encoder 15, which is connected to the drive of the drive unit 11, can be connected to the control device 12. The control device 12 comprises a processing element 16, which can receive load signals of the load sensors from the sensor device 13. Furthermore, the processing element 16 can receive a rotational angle signal and / or a rotational speed signal of an encoder device 17 of the rotary encoder 15. In this case, the rotary encoder 15 is coupled to the drive unit 11 via a shaft 18, which is configured to comprise a rope drum (not shown) and an electric motor (not shown) and a transmission device (not shown). The control unit 10 and the drive unit 11 are part of a hoist or crane, both of which are not shown in the present example.

[0042] The processing element 16 calculates load-related variables, such as a maximum threshold rotational speed, from the load signals of the sensor device 13 and the rotational angle signal and / or the rotational speed signal of the rotary encoder 15, based on which control signals are transmitted to the control unit 10 and status signals are received from the drive unit 11. The control device 12 can be programmed by means of the programming device 14, which can be a computer (not further shown). Furthermore, the control unit 10 comprises a counter 19, which can add the load signals of the sensor device 13 present in the processing element 16 over an operating period and thus can determine a total load. Thereby, a damage value is generated, which can be transmitted back from the counter 19 to the processing element 16, for example, in the form of a shutdown signal.

[0043] Figure 2 A control unit 20 is shown together with a drive unit 21 in a simplified illustration. The control unit 20 comprises a control device 22, a sensor device 23 with load sensors 36, 37, a programming device 24 and rotary encoders 25 and 38. The rotary encoders 25 and 38 themselves comprise an encoder device 26 and 39, respectively, a safety element 27 and 40, respectively, and a counter 28 and 41, respectively, and are connected to drives 43 and 44 of the drive unit 21 via shafts 29 and 42, respectively.

[0044] When operating the drive unit 21 or the drives 43 and 44, the rotary encoder 25 coupled to the drive 43 and the rotary encoder 38 coupled to the drive 44 detect the respective rotational angle signal and / or rotational speed signal by means of the respective encoder means 26 and 39 and transmit these signals to the control means 22. Furthermore, the rotary encoders 25 and 38 each receive a load signal from the sensor means 23 or the respective load sensors 36 and 37, and the safety elements 27 and 40 each determine a load-dependent variable, for example a maximum threshold rotational speed of each drive 43 and 44, from the respective rotational angle signal and / or the respective rotational speed signal and the respective load signal, and the maximum threshold rotational speed is each transmitted to the control means 22 in order to control the drive unit 21 or the drives 43 and 44.

[0045] Furthermore, each counter 28 and 41 each add the respective load signal over the operating period of the drives 43 and 44 and transmit a damage value to the control means 22. For example, when a certain damage value is reached, the control means 22 can switch off the drive unit. The control means 22 can be programmed by means of the programming means 24. The control means 22 can also receive and further process the load signal directly from the sensor means 23. The control means 22 receives a status signal from the drive unit 21 or the drives 43 and 44 and forwards it to the respective rotary encoders 25 and 38. The status signal relates to the type of operation of the drives 43 and 44, such as lifting or lowering the bearing load or slackening the rope.

[0046] The rotational angle signal and / or the rotational speed signal transmitted by the rotary encoders 25 and 38 to the control means 22 are further processed by the control means, so that for each drive 43 and 44 a respective rotational speed of the drives 43 and 44 is determined. The control means 22 compares the respective rotational speed with a reference rotational speed, which can be stored in the control means 22 in the form of a range parameter. Furthermore, it is also possible to define one of the two rotational speeds from the control means 22 as the reference rotational speed. It is important that the control means 22 controls the drives 43 and 44 depending on the comparison of the respective rotational speed with the reference rotational speed. For example, if the drives 43 and 44 are adjusted using the control means 22 as a result of the rotational speed of the drives 43 and 44 resulting from the respective rotational angle signal and / or the rotational speed signal of the rotary encoders 25 and 38, the control means 22 can define the rotational speed assigned to the drive 43 as the reference rotational speed. The rotational speed is now compared with the reference rotational speed, so that the rotational speed and the reference rotational speed are identical in the drive 43. The rotational speed of the drive 44 is adjusted depending on the reference rotational speed. Furthermore, the control means can also make a supplementary adjustment depending on the acceleration and / or the load.

[0047] Figure 3is a schematic view of the drive unit 21 with the rotary encoders 25 and 38. The rotary encoders 25 and 38 are coupled with the rope drums 30 and 45, respectively, by the ropes 31 and 46, respectively, and by the shafts 29 and 42, respectively, which means that the rotary encoders 25 and 38 can each detect the angle of rotation and / or the rotational speed of the rope drums 30 and 45. The rope drums 30 and 45 each have a rope breaker 32 and 47, respectively, and are each coupled to an electric motor 34 and 48, which drives the rope drums 30 and 45 by a transmission 33. Optionally, a further rotary encoder 35 can be coupled to the electric motor 34 and a further rotary encoder 49 can be coupled to the electric motor 48, so that the rotational speed of the electric motors 34 and 48 can be detected by the rotary encoders 35 and 49. The rotary encoders 35 and 49 can then be implemented essentially similar to the rotary encoders 25 and 38 and are components of the control unit 20.

Claims

1. A method for operating a conveying device, the conveying device comprising a drive unit (21) and a control unit (20) for controlling the drive unit, the drive unit comprising at least two drivers (43, 44), the drivers being controlled by a control device (22) of the control unit, rotary encoders (25, 35, 38, 49) of the control unit being connected to shafts (29, 42) of the drive unit of the conveying device and recording the rotation of the shafts, each shaft being assigned to a driver, and a rotation angle signal and / or rotation speed signal being transmitted to the control device via an encoder device (26, 39) of the respective rotary encoder to control the drivers. Its features are, The control device determines the corresponding rotational speed of the shaft and compares the rotational speed of the shaft with a reference rotational speed. The control device controls the driver based on the comparison. The control device defines or selects a reference acceleration based on one of the measured accelerations of the shaft.

2. The method according to claim 1, characterized in that, The conveying device is a hoist, crane, or continuous conveyor.

3. The method according to claim 1 or 2, characterized in that, The control device (22) determines the reference rotation speed based on the rotation angle signal and / or rotation speed signal of one of the rotary encoders (25), and adjusts each driver based on the reference rotation speed.

4. The method according to claim 3, characterized in that, The control device (22) determines the corresponding acceleration of the shaft (29, 42) and compares the acceleration of the shaft with a reference acceleration, and the control device adjusts each driver (43, 44) according to the reference acceleration.

5. The method according to claim 4, characterized in that, The control device (22) records the load signal from the load sensor (36, 37) of the sensor device (23) of the control unit (20) assigned to the driver (43, 44), and compares the load signal with a reference load, according to which the control device adjusts each driver.

6. The method according to claim 5, characterized in that, The control device (22) stores range parameters of rotational speed, acceleration and / or load, and the reference rotational speed, the reference acceleration and / or the reference load are all limited by the range parameters.

7. The method according to claim 5 or 6, characterized in that, The load signal from the load sensor is recorded by the rotary encoders (25, 35, 38, 49). Each rotary encoder determines a load-related variable based on the rotation angle signal and / or the rotation speed signal and transmits the load-related variable to the control device (22) to control the driver (43, 44).

8. The method according to claim 5 or 6, characterized in that, The control device (22) limits the rotational speed of the drive (43, 44) or shuts down the drive when it is overloaded.

9. The method according to claim 5 or 6, characterized in that, Load signals of the working point, rope load and / or winding load are recorded by multiple load sensors (36, 37) each assigned to the drive (43, 44).

10. The method according to any one of claims 1, 2, 5, or 6, characterized in that, The load signal is recorded by the load sensor (36, 37) assigned to the driver (43, 44) through the safety element (27, 40) of the corresponding rotary encoder (25, 35, 38, 49), the safety element determines the maximum threshold rotational speed related to the load based on the rotation angle signal and / or the rotational speed signal and the load signal, and transmits the maximum threshold rotational speed to the control device (22) to control the driver.

11. The method according to claim 10, characterized in that, The safety element (27, 40) determines the threshold rotation speed as a function of the rotation angle signal and / or the rotation speed signal and the load signal.

12. The method according to claim 10, characterized in that, The safety elements (27, 40) correct the load signals of the load sensors (36, 37) while taking into account the acceleration of the working load at the conveying device.

13. The method according to claim 10, characterized in that, The safety element (27, 40) determines the operation type of the drive (43, 44) as lifting, lowering, overload, slack rope, or no-load operation based on the rotation angle signal and / or the rotation speed signal and / or the load signal, and transmits the operation type of the drive to the control device (22).

14. The method according to claim 10, characterized in that, The rotary encoder (25, 35, 38, 49) records the switching signals of the terminal switches of the sensor device. The rotary encoder determines the relative position of the working load on the conveying device based on the switching signals. When determining the threshold rotational speed related to the load, the safety element (27, 40) takes the switching signals into account.

15. The method according to claim 10, characterized in that, The load signal is recorded by the counters (28, 41) of the rotary encoders (25, 35, 49), which store the rotation angle signal and / or rotation speed signal and the load signal during the operation cycle. The load-related damage value is determined and transmitted to the control device (22) to control the driver (43, 44).

16. The method according to claim 10, characterized in that, The load signal is recorded by the evaluation device of the rotary encoder (25, 35, 38, 49), and the evaluation device determines the weight of the working load at the conveying device based on the load signal and transmits the weight of the working load to the control device (22).

17. A control unit (20) for a conveying device, the conveying device including a control unit (22) and at least two rotary encoders (25, 35, 38, 49), the rotary encoders being connectable to shafts (29, 42) of the conveying device to record rotation of the corresponding shafts, the shafts being assigned to respective drivers (43, 44) of a drive unit (21), the rotary encoders including encoder devices (26, 39) for outputting rotation angle signals and / or rotation speed signals to the control unit (22) to control the drive unit. Its features are, The control device can determine the corresponding rotational speed of the shaft and compare the corresponding rotational speed of the shaft with a reference rotational speed. The control device controls the driver based on the comparison. The control device defines or selects a reference acceleration based on one of the measured accelerations of the shaft.

18. The control unit according to claim 17, characterized in that, The conveying device is a hoist, crane, or continuous conveyor.

19. The control unit according to claim 17 or 18, characterized in that, One of the rotary encoders (25, 35, 38, 49) includes the control device (22).

20. The control unit according to claim 19, characterized in that, The rotary encoders (25, 35, 38, 49) are incremental encoders and / or absolute encoders.

21. The control unit according to claim 19, characterized in that, The control unit (20) includes four or more rotary encoders (25, 35, 38, 49).

22. A conveying device comprising a control unit (20) according to claim 17 and a drive unit (21), the drive unit having at least two electric motors (34, 48), a transmission device and two rope drums (30, 45).

23. The conveying device according to claim 22, wherein the conveying device is a hoist or a crane.

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