WO2012013759A2

WO2012013759A2 - Measuring device, roll stand and method for operating the two devices

Info

Publication number: WO2012013759A2
Application number: PCT/EP2011/063052
Authority: WO
Inventors: Stefan Brombach
Original assignee: Sms Siemag Ag
Priority date: 2010-07-28
Filing date: 2011-07-28
Publication date: 2012-02-02
Also published as: WO2012013759A3

Abstract

The invention relates to a measuring device, to a roll stand and to associated methods for high-precision position detection. In order to increase the measuring precision and reliability of the measuring device in the form of a position sensor, according to the present invention the position sensor is designed as a photoelectric position sensor, and a signal transducer unit (120) associated with the photoelectric position sensor is designed to the effect that the position sensor measurement signal (S1) of the photoelectric position sensor is not only received and converted into the transducer output measurement signal using the desired signal format, but the amplitude of the position sensor measurement signal is also compared there to a predetermined amplitude threshold value.

Description

Measuring device and roll stand and method for operating the two devices

The invention relates to a measuring device with a position sensor for generating a position encoder measuring signal, which represents the respective current position of an actuator, and a signal converter device for converting the position encoder measuring signal into a converter output measuring signal having a desired signal format. The signal converter device is further configured to perform an integrated first monitoring function by comparing the amplitude of the position encoder measuring signal with a predetermined amplitude threshold value. Moreover, the invention relates to a corresponding measuring method, a roll stand with the said measuring device and a method for operating the roll stand.

In the prior art rolling mills are well known for rolling in particular metallic rolling. The rolling stands typically have two working rolls set against each other, which span a roll gap, for rolling the rolling stock. In addition to the work rolls, the rolling stands can also have support and intermediate rolls. The rolls are typically set or positioned by hydraulic cylinders as desired. The position of the adjusting cylinder or the rollers is typically detected and monitored by means of position encoders. Traditionally, typically magneto-magnetic, magnetoresistive, inductive or special sensors such as LVDT linear variable transformers have been used as locators. Other measuring principles, for example capacitive ones, are virtually not used because either the required measuring range can not be covered or the measuring accuracy is insufficient or because these position encoders can cope with the difficult ambient conditions. conditions when used on rolling stands (for example, high temperature or high humidity) can not withstand.

According to a traditional measurement chain, the position encoder measurement signal generated by the traditionally used position sensors is fed via a signal line to a signal converter which reads the position encoder measurement signal and converts it into a desired signal format, for example into a signal format suitable for a subsequent further processing. Finally, the converted signal is output via a further signal line to a control device, for example for the rolling stand. In addition to the functions mentioned, the traditional signal converter devices also perform various monitoring functions. These are, for example, monitoring the speed with which the position transmitter or an associated actuator is moved, monitoring the supply voltage provided for the position transmitter or monitoring the quality of the position sensor measuring signal, in particular by evaluating its amplitude. The results of these surveys are also traditionally provided at typically digital status outputs of the signal wall device for further use and processing. The tapping of this status information can be done for example with the help of a professional bus. An example of a traditionally used signal converter, also called a gateway, which is suitable for connection to the Profibus, is, for example, the signal converter "Profibus DPVO" from Leine & Linde GmbH, Aalen, Germany This not only results in the failure of the corresponding measuring system, but often also in the failure of a complete system, for example a rolling stand.These monitoring functions in the signal conditioners (condition monitoring) are therefore traditionally a tried and tested means for the plant operators, errors in the traditionally used Early detection of sensors and these demo- be replaced accordingly early, preferably before a failure of an entire system takes place.

The signal converter devices are always specially adapted to the particular position transmitter used, in particular to the position sensor measurement signal generated by it. Signal converter devices with the mentioned monitoring functions for realizing a desired condition monitoring are currently only available for the abovementioned traditionally used magnetostrictive, magnetoresistive or LVDT sensors. Such a measuring system consisting of position sensors and signal converters tuned thereto, as used in particular for rolling stands, is produced, for example, by Magnescale Europe GmbH, Mori Seiki Co. Ltd. offered. The position encoder comprises a scale MSS 976 R and a read head HA-705-Lk-907. A suitable signal converter (gateway) is the MD 50 2 N (2 channels) or the MD 50 4 N (4 channels).

However, the mentioned and traditionally used position encoder types often no longer meet today's requirements for high measuring accuracy in the micrometer range. To achieve these measurement accuracies, photoelectric position sensors are preferably used. An example of such a photoelectric position sensor with a resolution in the micrometer range is known from the series LIA Numerik Jena. Another advantage of these known photoelectric position sensor is the extended measuring range, which meets the requirements in the field of rolling technology. The disadvantage of this optically scanning position sensor is that it is more susceptible to contamination than the above-mentioned traditionally used sensors. It is therefore preferably installed in a rolling mill-compatible protective housing.

Photoelectric encoders are not signal compatible with known signal transducers having said integrated monitoring functions. Based on this prior art, the present invention has the object, a known measuring device, an associated measuring method, a known rolling stand and an associated method for operating the rolling mill further to the effect that detects the position of actuators with a higher accuracy and at the same time the reliability, in particular the reliability of the position sensor and the roll stand can be increased.

This object is first achieved by the claimed measuring device. This measuring device is characterized in that the position sensor is designed in the form of a photoelectric position sensor and the signal conversion device is adapted to receive the position sensor measuring signal of the photoelectric position sensor, convert into the Wandlerausgangsmesssig- signal with a desired signal format and in the context of an integrated first monitoring function, the amplitude of Position encoder measuring signal to compare with a predetermined amplitude threshold. The result of this comparison is preferably output at a first status output of the signal converter device.

This claimed measuring device advantageously combines the very high measuring accuracy of the photoelectric position sensor in the micrometer range with the first monitoring function for the position sensor. The amplitude comparison in the context of the first monitoring function can advantageously be a conclusion to the operability of the position sensor and / or the protective housing and / or an associated actuator of a system, for example a rolling stand to. In this way, the reliability of the position sensor and the system is significantly increased.

The claimed conversion of the signal format is required in order to output the position encoder measurement signal or the converter output measurement signal to a control device of the system can. The control device is in usually only able to recognize and process a particular, the desired signal format.

The control device or the automation system of the system can be advantageously supplied with the aid of the present invention preferably in real time with highly accurate position measurement data, which are also reliable due to the monitoring function (s) performed.

According to a first embodiment, the photoelectric position sensor is advantageously designed to represent the position of the actuator with a resolution of 80-1 microns, preferably even 50-1 microns. Furthermore, it can be provided that, after an interpolation of the position encoder measuring signal in the signal converter device, the converter output measurement signal (S3) represents a resolution for the position of the actuator (120) of 10-1 pm, preferably 4-0.01 pm.

The direct coupling of the photoelectric position sensor with its output signal to the signal converter means, without intermediate transformers are connected therebetween, offers the advantage of greater measurement accuracy and signal representation. According to the invention, the signal converter device is designed to receive the position encoder measurement signal and to convert it into the desired signal format. An intermediate conversion is undesirable because of the associated additional fault liability and also not required. In accordance with a second monitoring function, which is likewise preferably realized in the signal converter device, the supply voltage provided for the photoelectric position transmitter is compared with at least one predetermined voltage threshold value and the result is displayed at a second status output of the signal converter device. In this way, condition monitoring ensures that a fault in the power supply of the photoelectric position sensor takes place in good time can be detected and corrected before the locator may fail completely.

As part of a third monitoring function, the speed derived from the position encoder measurement signal and / or the determined acceleration with which a change in the position of the actuator is compared with a predetermined speed and / or acceleration threshold value and the result of this comparison on a If the predetermined speed and / or acceleration threshold values are exceeded or exceeded, the result can be a defect in the position transmitter or in the actuator. Individual or both components can then be replaced immediately, in some cases long before routine check-ups, which typically only occur at longer intervals. Furthermore, a calibration function can be provided in the signal converter device for recalibrating the photoelectric position sensor. The recalibration comprises, in particular, an automatically regulated adaptation of the input impedance of the signal converter device to the impedance of the line between the position transmitter and the signal converter device. The recalibration can be displayed on a fourth status output of the signal converter device.

The second and third monitoring functions as well as the calibration function may be present individually or in combination in addition to the first monitoring function.

The status signals at the status outputs of the signal converter simplify troubleshooting and increase operational safety and system availability. The status outputs enable an alarm to be generated upon reaching or exceeding or falling below the specified threshold values. Advantageously, the signal converter device can be connected to a data bus, for example the profile bus, preferably the real-time bus EtherCat. In particular, the status outputs of the signal converter can be conveniently read out via the data bus. Signal converters can also be parameterized remotely via the bus interface. The signal converter device with its numerous functions is preferably designed in the form of a Field Programmable Gate Array FPGA.

The abovementioned object of the invention is furthermore achieved by a measuring method, a rolling stand with the claimed measuring device and by a method for operating the rolling stand. The advantages of these solutions correspond to the advantages mentioned above with reference to the claimed measuring device. With reference to the claimed rolling stand, which is an example of the system mentioned in claim 1, it should be mentioned that the actuators according to the invention are, for example, hydraulic cylinders. These can be used in the roll stand for different functions and, accordingly, also at different positions in the roll stand. For example, a first actuator can be a setting cylinder for setting the roller perpendicular to the plane xz of the rolling stock to be rolled, that is, for adjusting the rolling gap of the rolling stand. A second actuator may serve to displace the roller in its axial direction z. A third actuator may be configured to move the roller in or against the rolling direction x parallel to the plane xy of the rolling stock (horizontal shifting). Finally, a fourth actuator may also be designed as a bending device, in particular as a bending cylinder for setting a desired bending of the roller, in particular the working and / or intermediate rollers. In the adjusting device, individual or a combination of the first, second, third and fourth actuators may be provided.

The term "roller" in the sense of the invention means a work roll, a support roll and / or an intermediate roll in the roll stand.

To protect the photoelectric position sensor against the harsh environment of the rolling stand during operation, in particular for protection against excessive temperatures and against contaminated air or atmosphere, the position sensor is advantageously installed in a protective housing. The first monitoring function advantageously makes it possible, in particular, to monitor the protective housing for mechanical errors (leaks and / or mechanical games) and to predict a possible failure on the basis of the signal amplitude.

The description is attached to two figures, wherein

Figure 1 shows the measuring chain of the present invention; and FIG. 2 shows a rolling stand with the photoelectric according to the invention

Positioners shows.

The invention will be described in detail below with reference to the said figures in the form of embodiments. In all figures, the same technical features are designated by the same reference numerals. FIG. 1 shows the measuring device 100 according to the invention as part of a measuring chain. The measuring device 100 initially comprises a photoelectric posi- tion generator 1 10, which is associated with a system, for example a rolling stand. The position sensor 1 10 is followed directly, without the interposition of an intermediate converter means, a signal converter means 120 downstream. The signal converter device 120 supplies the position transmitter 1 10 with a supply voltage U. The photoelectric position sensor 1 10 generates a position transmitter measuring signal S1 as an output signal, which is received by the signal converter device 120. The signal converter device 120 is designed to convert the received position encoder measurement signal S1 into a desired signal format and to output the resulting signal as a converter output measurement signal S3, for example to a controller 200 for the system (not shown in FIG. 1). The desired signal format corresponds to the signal format, which can be received and processed by the control device. The control device 200 may generally be an automation device, in particular also a control device. The control device 200 is typically designed to control at least one actuator 320 of the system, preferably taking into account the received converter output measurement signal S3. The signal lines shown in FIG. 1 for transmitting the position encoder measuring signal S1, the converter output measuring signal S3 and for controlling the actuator 320 may be formed at least partially in the form of optical waveguides. The use of optical waveguides offers the advantage of low losses in signal transmission over long distances and low susceptibility to interference, in particular to electromagnetic interference. The signal transmission on all the said signal lines is preferably in real time.

Preferably, the signal converter device 120 is adapted to be coupled to a preferably digital data bus, for example the Profibus. Especially recommended for use in metallurgical plants, such as rolling mills, is the real-time bus EtherCat. This bus has the advantage that both the position encoder measuring signal and the status signals generated by the signal converter device 120 and the transducer output measurement signal may preferably be transmitted jointly via the bus.

The preferably digital status signals output at the status outputs 121, 122, 123, 124 of the signal converter device 120 can, for example, be output via the data bus 130 to the control device 200 and / or a display device 500.

FIG. 2 shows a preferred application for the measuring device according to the invention, namely a rolling stand 300. The rolling stand 300 comprises two opposing work rolls 310, which are arranged at a distance from one another and span a rolling gap for rolling rolling stock 400. In addition to the work rolls 310, the roll stand 300 optionally includes the intermediate rolls 312 and support rolls 314, likewise shown in FIG. 2, which are mounted so as to be displaceable in bearing housings, so-called chocks, in the stand window 330 of the rolling mill stand 300. In FIG. 2, the rolling direction is designated by the parameter x. From this, the parameters y and z denote the other Cartesian coordinates.

In Figure 2, actuators 320 are further shown for hiring the rollers, in particular the work rolls. Thus, the first actuator 320-1 is adapted to effect a vertical adjustment of the rollers and in particular the work rolls and thus an adjustment of the size of the nip between the work rolls. Furthermore, actuators 320-2 are shown, which may be formed as a bending device for setting a desired bending of the work rolls 310 and / or the intermediate rolls 312. In addition to the two shown actuators for vertical adjustment and bending further actuators for axial and horizontal displacement of particular Work rolls can be provided, which are not shown in Figure 2. All or at least some of said actuators are according to the invention associated with photoelectric position sensor 1 10 for detecting the respective current position of the actuators 320, preferably with a resolution of 1-100 microns, preferably 1-50 microns. The position of the actuator thus detected is in each case represented by the position sensor measurement signal S1 generated by the position transmitter 110 and supplied to the signal converter device 120 according to FIG.

Apart from the conversion to a desired signal format, the position encoder measurement signal S1 is evaluated in the signal converter device 120 in various ways. A first evaluation takes place within the framework of a performance of a first monitoring function, which provides that the amplitude of the position encoder measuring signal S1 is compared with a predetermined amplitude threshold value. Such monitoring of the signal level or the amplitude allows a statement about the quality of the position encoder measurement signal. The signal quality in turn allows a statement about the functionality of the position sensor 1 10 or its associated parts of the system, in particular the actuators 320 or the protective housing. By appropriate selection of the amplitude thresholds, a statement can be made as to whether the amplitude of the position encoder measurement signal reaches the predetermined amplitude threshold value to 100% or only to a limited extent, for example to 87, 63 or even only 44% percent. As a result of this monitoring in the signal converter device 120, it is possible to draw conclusions about the general and / or mechanical state of, in particular, the measuring device 100, more particularly the position measuring device 110.

Example:

The photoelectric encoder typically includes an optoelectronic readhead and a high resolution ruler in the micrometer range, wherein in one measurement either the ruler on the readhead or vice versa, the readhead is pushed past the ruler. In this way The position of, in particular, the actuator 320 is determined precisely. Long periods of operation can cause soiling and / or wear, such as knock-outs or mechanical play. These fouling or wear can also occur, although the photoelectric position sensor is preferably housed in a protective housing. If the threshold comparison shows that the position encoder 1 10 no longer delivers the full amplitude, this suggests that the said mechanical wear or contamination of the position sensor. In addition to the first monitoring function, a second monitoring function can be integrated in the signal converter device 120. This second monitoring function provides for comparing the supply voltage U, which is typically provided by the signal converter device 120 for the position transmitter 1100, with at least one predetermined voltage threshold value. In this way it can be easily checked whether the supply voltage for the position sensor 1 10 does not fall below a predetermined minimum value. The result of this comparison is preferably output at a second digital status output 122 of the signal converter device 120. Furthermore, a third monitoring function can be integrated in the signal converter device 120, the position encoder measuring signal S1 being evaluated with regard to the speed and / or the acceleration with which the change of the position of the actuator takes place. The thus determined speed and / or acceleration is in each case compared with a predefined speed and / or acceleration threshold value, and the result of this comparison is preferably output digitally at a third status output 121 of the signal converter device 120. Alternatively, the third monitoring function can also provide that no comparison takes place and that the determined speed and / or acceleration as such is output eg via the data bus from the signal converter device. A detected deviation, for example the determined acceleration from the acceleration threshold value, may indicate a more or less existing play of the mechanical components in the roll stand, for example play of the chocks of the rolls 310, 312, 314 or play with the position sensor not mounted correctly.

Furthermore, a calibration function can be integrated in the signal converter device, which checks, for example, whether the calibration of the photoelectric position sensor is still correct. With or without such prior checking, the integrated calibration function is configured to recalibrate the photoelectric position sensor.

Finally, an interpolation function can be integrated in the signal converter device which interpolates the received position encoder measurement signal. The transducer output measurement signal then represents the interpolated (and typically also converted) position encoder measurement signal. The interpolation has the advantage that the resolution of the position of the actuator associated with the position transmitter can be specified even more accurately than by the non-interpolated position sensor measurement signal. While the photoelectric position encoder measurement signal already enables a resolution of 80-1 pm, preferably 50-1 pm, the interpolated position encoder measurement signal or the converter output measurement signal permits a resolution of 10 -1 pm, preferably 4 - 0.01 pm. The signal converter device 120 with the integrated first, second and / or third monitoring function and optionally also with the calibration function and the interpolation function is preferably in the form of a field-programmable gate array. The signal converter 120, also called a gateway, provides the status signals which enable monitoring, in particular, of the position transmitter 110, but also of the associated system parts; Keyword: "Condition Monitoring" be designed to provide certain additional information, such as operating time, error rate, type of error, semi-absolute position and the above-mentioned monitoring functions or provide. To provide the semi-absolute position, the signal converter device 120 preferably receives a position value via the data bus. For this position value, the signal converter device 120 can add, depending on the direction, the respective current position, which is represented by the position encoder measuring signal S1, and the thus formed semi-absolute position can subsequently be interrogated again via the data bus.

LIST OF REFERENCE NUMBERS

100 measuring device

1 10 position transmitter

120 signal transducers

121 First status output

122 Second status output

123 Third status output

124 Fourth status output 130 data bus

200 control device for rolling stand

300 rolling stand

310 stripper

312 intermediate roller

314 back-up roll

320 actuator

330 pedestal window

400 rolling stock

500 display device

S1 position encoder measurement signal S3 transducer output measurement signal

U Supply voltage for position encoder

x rolling direction

z width direction of the rolling stock, longitudinal direction of the rolls y direction perpendicular to the plane of the rolling stock.

Claims

claims:

1 . Measuring device (100) with:

a position sensor (1 10) for generating a position encoder measuring signal (S1), which represents the respective current position of an associated actuator (320) of a system; and

a signal converter (120) for converting the position encoder signal (S1) into a converter output measurement signal (S3) having a desired signal format, the signal converter means (120) having an integrated first monitor function for comparing the amplitude of the encoder signal with a predetermined amplitude threshold;

characterized in that

the position sensor (1 10) is designed in the form of a photoelectric position sensor; and

the signal converting means (120) is adapted to receive the position encoder measuring signal (S1) of the photoelectric position sensor, to convert it to the converter output measuring signal (S3) with the desired signal format, and to compare the amplitude of the photoelectric position encoder measuring signal with the predetermined amplitude threshold value.

2. Measuring device (100) according to claim 1,

characterized,

in that the position sensor measurement signal of the photoelectric position sensor of the signal converter device (120) represents a resolution for the position of the actuator of 80-1 pm, preferably 50-1 pm; and or

in that the transducer output measurement signal (S3) has a resolution for the position of the actuator (120) of 10-1 pm, preferably after interpolation of the position encoder measurement signal in the signal converter device represented by 4-0.01 μΓΠ.

3. Measuring device (100) according to one of the preceding claims,

characterized in that the signal converter means (120) is the photoelectric position sensor (1 10) immediately downstream.

4. Measuring device (100) according to one of the preceding claims, characterized in that when the first monitoring function is executed, the result of the comparison is output at a first status output (121) of the signal converter device.

5. Measuring device (100) according to one of the preceding claims,

characterized in that

the signal converter device (120) is designed to carry out a second monitoring function, in which the supply voltage (U) provided for the photoelectric position sensor (110) is compared with at least one predetermined voltage threshold value and outputting the result of this comparison at a second status output (122 ) of the signal converter device.

6. Measuring device (100) according to one of the preceding claims,

characterized in that

the signal converter means (120) is adapted to carry out a third monitoring function in which the received position encoder measurement signal is evaluated with regard to the speed and / or the acceleration with which a change in the position of the actuator (320); and wherein the determined speed and / or the determined acceleration are output and / or compared with a predetermined speed and / or acceleration threshold value and the result of this comparison is output at a third status output (123) of the signal converter device (120). will give.

7. Measuring device (100) according to one of the preceding claims,

characterized in that

the signal converter means (120) is adapted to perform a calibration function in which the photoelectric encoder (110) is recalibrated, preferably after previously detecting a misalignment of the photoelectric encoder, and indicating the successful or unsuccessful recalibration at a fourth status output (124) the signal converter means (120).

8. Measuring device (100) according to one of the preceding claims,

characterized in that

the signal converter device (120) is connectable to a data bus (130), preferably the bus EtherCat, for reading out the first, second, third and / or fourth status output (121, 122, 123, 124) via the data bus.

9. Measuring device (100) according to one of the preceding claims,

characterized in that

the signal converter device (120) is designed in the form of a Free Programmable Gate Array FPGA.

10. Measuring device (100) according to one of the preceding claims,

characterized in that

the first, second and / or third monitoring function and preferably also the calibration function and / or an interpolation function are integrated in the signal converter device (120).

1 1. Measuring method with the following steps:

Generating a position sensor measuring signal (S1), which the respective ak- represents the current position of an associated actuator (320);

Converting the position encoder measurement signal (S1) in a signal converter means (120) into a converter output measurement signal (S3) having a desired signal format; and

Performing a first monitoring function in the signal converter means (120) by comparing the amplitude of the position encoder measurement signal with a predetermined amplitude threshold value;

characterized in that

the position sensor measuring signal (S1) is generated as an output signal from a photoelectric position sensor (1 10); and

the position sensor measurement signal (S1) of the photoelectric encoder in the signal converter means (120) is converted into the converter output measurement signal (S3) having the desired signal format and the amplitude of the position encoder measurement signal is compared with a predetermined amplitude threshold value.

12. Measuring method according to claim 1 1,

characterized in that the position sensor measurement signal (S1) of the photoelectric position sensor represents a resolution for the position of the actuator (120) of 80-1 pm, preferably 50-1 pm; and or

the transducer output measurement signal (S3), after interpolation of the position encoder measurement signal in the signal converter device, represents a resolution for the position of the actuator (120) of 10-1 pm, preferably 4-0.01 pm.

13. measuring method according to claim 1 1 or 12,

characterized in that the position sensor measuring signal (S1) of the photoelectric position sensor (1 10) without intermediate conversion directly into the signal converter means (120) and there converted into the Wandlerausgangsmesssignal (S3).

14. Measuring method according to one of the preceding claims 1 1 to 13, characterized in that

when the first monitoring function is exercised, the result of the amplitude comparison is output at a first status output (121) of the signal converter device.

15. Measuring method according to one of the preceding claims 1 1 to 14, characterized in that

for carrying out a second monitoring function, the supply voltage (U) provided for the photoelectric position sensor (110) is compared with at least one predetermined voltage threshold value and the result of this comparison is output at a second status output (122) of the signal converter device.

16. Measuring method according to one of the preceding claims 1 1 to 15, characterized in that

for performing a third monitoring function, the position encoder measuring signal is evaluated with regard to the speed and / or the acceleration with which the change of the position of the actuator takes place, and the determined speed and / or the determined acceleration is output and / or with a predetermined speed and / or acceleration threshold value is compared and the result of this comparison at a third status output (123) of the signal converter means (120) is output.

17. Measuring method according to one of the preceding claims 1 1 to 16, characterized in that

recalibration of the photoelectric position sensor is performed automatically or manually, preferably after a misalignment of the photoelectric position sensor has previously been detected, and an indication of successful or unsuccessful recalibration at a fourth status output (124) Signal converter device takes place.

18. Roll stand (300) for rolling a rolling stock (400), comprising:

at least one roller (310, 312, 314);

an adjusting device with at least one actuator (320) for adjusting the roller (310, 312, 314);

at least one position sensor (110) associated with the actuator for generating a position encoder measuring signal (S1), which represents the respectively current position of the actuator and thus the current position of the at least one roller;

signal conversion means (120) for converting the position encoder measurement signal into a transducer output measurement signal (S3) having a desired signal format and performing a first monitor function by comparing the amplitude of the position encoder measurement signal with a predetermined amplitude threshold; and control means (200) for controlling the rolling stand (300) and driving the actuator (320) in accordance with the received transducer output measurement signal (S3);

characterized in that

the signal converter means (120) is adapted to receive the position encoder measurement signal (S1) of the photoelectric position sensor, to convert it to the converter output measurement signal (S3) with the desired signal format, and to compare the amplitude of the position encoder measurement signal with the predetermined threshold value.

19. roll stand (300) according to claim 18,

characterized,

the position sensor measuring signal (S1) of the photoelectric position sensor of the signal converter device (120) represents a resolution for the position of the actuator of 80-1 pm, preferably 50-1 pm. advantage; and or

the converter output measurement signal (S3) represents a resolution for the position of the actuator (120) of 10-1 pm, preferably of 4-0.01 μm, after an interpolation of the position encoder measurement signal in the signal converter device.

20. rolling stand (300) according to claim 18 or 19,

21. Rolling stand (300) according to one of the preceding claims 18 to 20, characterized in that

the adjusting device comprises a first actuator (320-1) for adjusting the roller (310, 312, 314) in a direction (y) perpendicular to the plane (x, z) of the rolling stock to be rolled.

22. Rolling mill (300) according to one of the preceding claims 18 to 21, characterized in that

the adjusting device has a second actuator for setting the roller (310) in the axial direction (z) of the roller.

23. rolling stand (300) according to one of the preceding claims 18 to 22, characterized in that

the adjusting device has a third actuator for displacing the roller in a direction (x) parallel to the plane of the rolling stock in or counter to the rolling direction (x).

24. Roll stand (300) according to one of the preceding claims 18 to 23, characterized in that

the adjusting device has a fourth, the actuator (320-2), which is designed as a bending device for setting a desired Bend of the roller.

25. rolling stand (300) according to one of the preceding claims 18 to 24, characterized in that

the signal converter device (120) is designed, in the execution of the first monitoring function, the result of the amplitude

Preferably output comparison at a first status output (121) of the signal converter means.

26. rolling stand (300) according to one of the preceding claims 18 to 25, characterized in that

the signal converter device (120) is designed to carry out a second monitoring function, in which the supply voltage (U) provided for the photoelectric position sensor (110) is compared with at least one predetermined voltage threshold value and outputting the result of this comparison at a second status output (122 ) of the signal converter means (120).

27. rolling stand (300) according to one of the preceding claims 18 to 26, characterized in that

the signal converter device (120) is designed to carry out a third monitoring function, in which the position encoder measurement signal is evaluated with regard to the speed and / or the acceleration with which the position of the actuator is changed by the determined speed and / or the issued acceleration and / or each with a predetermined

Compare speed and / or acceleration threshold and output the result of this comparison at a third status output (123) of the signal converter means (120).

28. rolling stand (300) according to one of the preceding claims 18 to 27, characterized in that the signal converter means (120) is adapted to perform a calibration function in which the photoelectric encoder is recalibrated, preferably after previously detecting a misalignment of the photoelectric encoder, and indicating the successful or unsuccessful recalibration at a fourth status output (124) signal converter device.

29. Roll stand (300) according to one of the preceding claims 18 to 28, characterized in that

the signal converter device (120) is connectable to a data bus (130), preferably the bus EtherCat, for reading out the status outputs via the data bus.

30. Roll stand (300) according to one of the preceding claims 18 to 29, characterized in that

the signal converter device (120) with the integrated first, second and / or third monitoring function and preferably also with the calibration function and / or an interpolation function is designed in the form of a Free Programmable Gate Array FPGA.

31. Rolling stand (300) according to one of the preceding claims 18 to 30, characterized in that

the at least one roller is a work roll (310), a backup roll (314) or an intermediate roll (312).

32. Roll stand (300) according to one of the preceding claims 18 to 31, characterized in that

a protective housing is provided for receiving the photoelectric position sensor (1 10).

33. A method for operating a rolling stand (300) having at least one roller (310, 312, 314) for rolling a rolling stock (400), with an adjusting device with at least one actuator (320) for adjusting the roller, with at least one associated with the actuator Position sensor (1 10) for generating a position encoder measuring signal (S1), which represents the respective current position of the actuator (320) and thus the current position of the at least one roller, with a signal converter means (120) and with a control device (200) for controlling the rolling stand (300) and for driving the actuator (320), the method comprising the steps of:

Converting the position encoder measurement signal (S1) into a transducer output measurement signal (S3) of the signal converter device (120) having a desired signal format;

Performing a first monitoring function in the signal converter means by comparing the amplitude of the position encoder measurement signal with a predetermined amplitude threshold; and

Activating the actuator (120) in accordance with the received transducer output measurement signal (S3);

characterized in that

the position sensor measuring signal (S1) is generated by the position sensor (1 10) in the form of a photoelectric position sensor; and converting the position encoder measurement signal of the photoelectric position sensor in the signal converter means (120) into the converter output measurement signal (S3) having the desired signal format and comparing the amplitude of the position encoder measurement signal with the predetermined amplitude threshold value.

34. The method according to claim 33,

characterized in that

the position sensor measurement signal (S1) of the photoelectric encoder of the signal converter means (120) represents a resolution for the position of the actuator of 80-1 m, preferably 50-1 m; and

the transducer output measurement signal (S3) represents a resolution for the position of the actuator (120) of 10-1 .mu.m, preferably of 4-01 .mu.m, after an interpolation of the position encoder measurement signal in the signal converter device.

35. The method according to claim 33 or 34,

characterized in that the method further comprises the steps of the measuring method according to one of claims 13 to 17.