TRANSPORT DEVICE HAVING AT LEAST ONE CHAIN

Abstract

The invention relates to a transport device (100), in particular for transporting product carriers in a plant for manufacturing food products. The transport device (100) comprises at least one chain (1) to which measuring marks (4) are attached, an electrical drive system (20) for driving the chain (1) with a servo motor (25) and an absolute encoder (21), a plant control unit (30) and a measuring sensor (11) for detecting the measuring marks (4) with a switching frequency of greater than 2000/s. The plant control unit (30) comprises a first input (34) for receiving measurement data from the measuring sensor (11) and a second input (35) for receiving position data from the position sensor (21) and is designed to receive data from the measuring sensor (11) and from the position sensor (21), to mutually correlate said data correctly with respect to time, to determine therefrom lengths between measurement marks (4), more particularly between two consecutive measurement marks, and to produce a signal which provides information about the quality of the chain. A servo position actual value is ascertained by means of oversampling. (FIG. 2)

Claims

1-13. (canceled)

14. A transport device, having a. at least one chain, to which measuring marks are attached, b. an electric drive system for driving the at least one chain, comprising a servo motor and a position sensor, namely an absolute encoder, c. a plant control unit, d. a measuring sensor for detecting the measuring marks, with a switching frequency of greater than 2000/s, wherein the plant control unit comprises a first input for receiving measurement data from the measuring sensor and a second input for receiving position data from the position sensor and wherein the plant control unit is designed, to receive data from the measuring sensor and from the position sensor, to mutually correlate said data correctly with respect to time, to determine therefrom lengths between and to generate a signal which provides information about the quality of the chain, wherein the transport device comprises a processor unit for data preprocessing, which serves as an input card for the plant control unit and which has an input for data detected by the measuring sensor and an output for passing the data on to the plant control unit, having an oversampling function for determining a subclock in the event of a signal change at the input, and the plant control unit being designed to allocate a servo position actual value corresponding to the position of the drive in the event of a signal change with temporal accuracy.

15. The transport device according to claim 14, wherein the transport device is for transporting product carriers in a plant for producing food products.

16. The transport device according to claim 14, wherein the plant control unit is designed to allocate a servo position actual value corresponding to the position of the drive in the event of a signal change with temporal accuracy via the following relationship:
P.sub.x=(P.sub.t2−P.sub.t1)*(X.sub.pos−1)/OVS+P.sub.t1 [mm], wherein P.sub.x the servo position actual value to be determined, P.sub.t1 the servo position at time t1 with a bus clock, P.sub.t2 the servo position at time t2 at a subsequent bus clock, X.sub.pos the subclock at which a signal change from 0 to 1 takes place.

17. The transport device according to claim 14, wherein the measuring sensor is an inductive or optoelectronic sensor.

18. The transport device according to claim 14, wherein the at least one chain comprises at least one reference measuring mark.

19. The transport device according to claim 18, wherein the at least one reference measuring mark has a geometry differing from the other measuring marks.

20. The transport device according to claim 14, wherein the plant control unit is designed to synchronize received data with the plant clock.

21. The transport device according to claim 14, wherein the plant control unit comprises a plant clock, and the transport device has a clock-synchronous bus system for at least one of synchronizing the plant control unit and the electrical drive system and synchronizing the plant control unit and the incoming measurement data.

22. The transport device according to claim 14, wherein the plant control unit is adapted to at least one of a. to store raw data, b. to determine measurement events from measurement data, c. to determine lengths between measurement events and d. to detect changes in lengths between measurement events.

23. The transport device according to claim 14, wherein the plant control unit has at least one output and is designed to forward data.

24. The transport device according to claim 23, wherein the plant control unit is designed to forward data to at least one of a display unit and a cloud.

25. The transport device according to claim 14, wherein the electric drive system comprises an actuator with interface for data exchange with the plant control unit.

26. The transport device according to claim 25, wherein the interface is a frequency converter.

27. A plant for producing a food product comprising at least one transport device according to claim 14.

28. A method for determining lengths of segments of a chain which is driven by an electric drive, wherein a measuring sensor detects measuring marks applied to the chain, wherein data detected by the measuring sensor and data transmitted by an absolute encoder of a servomotor, which drives the chain, are assigned to one another with correct timing, a servo position actual value being determined by means of over-sampling, lengths between measurement marks are determined therefrom, and a signal is generated which provides information about the quality of the chain.

29. The method according to claim 28, wherein the electric drive is part of a transport device, having a. at least one chain, to which measuring marks are attached, b. an electric drive system for driving the at least one chain, comprising a servo motor and a position sensor, namely an absolute encoder, c. a plant control unit, d. a measuring sensor for detecting the measuring marks, with a switching frequency of greater than 2000/s, wherein the plant control unit comprises a first input for receiving measurement data from the measuring sensor and a second input for receiving position data from the position sensor and wherein the plant control unit is designed, to receive data from the measuring sensor and from the position sensor, to mutually correlate said data correctly with respect to time, to determine therefrom lengths between and to generate a signal which provides information about the quality of the chain, wherein the transport device comprises a processor unit for data preprocessing, which serves as an input card for the plant control unit and which has an input for data detected by the measuring sensor and an output for passing the data on to the plant control unit, having an oversampling function for determining a subclock in the event of a signal change at the input, and the plant control unit being designed to allocate a servo position actual value corresponding to the position of the drive in the event of a signal change with temporal accuracy.

30. The method according to claim 28, wherein for determining the servo position actual value the following relation is used:
P.sub.x=(P.sub.t2−P.sub.t1)*(X.sub.pos−1)/OVS+P.sub.t1 [mm], wherein P.sub.x the servo position actual value to be determined, P.sub.t1 the servo position at time t1 with a bus clock, P.sub.t2 the servo position at time t2 at a subsequent bus clock, X.sub.pos the subclock at which a signal change from 0 to 1 takes place.

31. The method according to claim 28, wherein at least one of a. raw data are stored, b. measurement events are determined from measurement data, c. lengths between measurement events are determined and d. changes in lengths between measurement events are detected.

32. The method according to one claim 28, wherein a plant control unit synchronizes measurement data detected by the measuring sensor and data transmitted by a position sensor of the electric drive by means of a clock-synchronous bus connection.

33. A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to perform the steps of the method of claim 28.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The invention is explained below in embodiment examples based on drawings.

[0103] They show

[0104] FIG. 1 a part of a transport device in perspective view;

[0105] FIG. 2 a schematic representation of a transport device;

[0106] FIG. 3a a schematic representation of a carrier;

[0107] FIG. 3b a schematic representation of a reference mark;

[0108] FIG. 3c a schematic representation of a measuring pattern of the carrier;

[0109] FIG. 3d a schematic representation of a measuring pattern of the reference mark;

[0110] FIG. 4 a perspective view of a measuring mark guide.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0111] FIG. 1 shows a part of a transport device 100 in perspective view.

[0112] The transport device 100 comprises a chain 1, to which measuring marks 4 are attached at regular intervals, and an electric drive system 20 for driving the chain 1. A section of the chain, in particular the section of the chain between two measuring marks 4, is called segment 2.

[0113] A measuring sensor 11 is mounted as far as possible from the electric drive system 20. With a measurement of the chain on the drive wheel 18 or in the immediate vicinity of the drive wheel 18, no or hardly any change in position could be detected, since the links of the chain 1 are forced onto the pinions of the drive wheel 18 and therefore maintain a defined distance there.

[0114] The measuring sensor 11 can be directed towards the empty run 17.

[0115] FIG. 2 shows a schematic representation of a transport device 100.

[0116] The electric drive system 20 comprises an electric motor 25, a position sensor 21, in this case an absolute encoder, a gear 22 and an actuator 23.

[0117] The transport device 100 comprises a plant control unit 30, which is synchronized with the electric drive system 20 via a clock-synchronous bus system 16. The plant control unit 30 controls the actuator 23, for example a frequency converter, and receives position data from the absolute encoder 21 via an input 35.

[0118] The transport device 100 further comprises a measuring sensor 11 for detecting the measuring marks 4 on the chain 1.

[0119] The plant control unit 30 has a first input 34 for receiving measurement data from the measuring sensor 11 and a second input 35 for receiving position data from the position sensor 21. The transport device 100 is designed to receive data from the measuring sensor 11 and from the position sensor 21, to assign them to each other in correct time and to determine therefrom lengths 3 between, in particular two consecutive measuring marks 4.

[0120] The plant control unit 30 may have a module for monitoring mechanical assemblies, for example a Simatic S7-1500.

[0121] The transport device 100 comprises a processor unit 13 for data pre-processing, which has an input 14 for data acquired by the measuring sensor 11 and an output 15 for passing the data on to the plant control unit 30, in particular by means of the clock-synchronous bus system 16.

[0122] The processor unit 13 may be a high-speed input card, for example a Simatic ET200SP.

[0123] The plant control unit 30 has at least one output 37 and is designed to forward data, in particular to a cloud 18.

[0124] FIG. 3a shows a schematic representation of a carrier 4 having a substantially triangular shape. FIG. 3b shows a schematic representation of a reference marker 5, which is designed as a carrier with a deviating geometric shape and has a hole 6.

[0125] FIG. 3c shows a schematic representation of a measurement pattern 7 generated by a carrier 4 according to FIG. 3a on an optical sensor 11. FIG. 3d shows a schematic representation of a measuring pattern 8, which generates a reference mark 6 according to FIG. 3b at the optical sensor 11.

[0126] For the length evaluation, the time at which the steep edge of the carrier 4 or the reference mark 5 passes the sensor 11 is preferably used.

[0127] FIG. 4 shows a guide rail 9 in perspective view. To ensure that the measuring marks 4 are at a defined distance from the measuring sensor 11, the measuring marks 4 are guided along between two guide jaws 10 as they pass the measuring sensor 11.