RU2275589C2 - Method of measuring length of rolling - Google Patents

Abstract

FIELD: control equipment.

SUBSTANCE: length to be measured is divided to several basic parts and position of end of rolling is determined by means of photoreceivers and irradiators disposed in opposition to photoreceivers. Irradiators are installed along borders of basic parts. Measurements are made inside basic parts by means of pulse detector, which pulses come from drive of displacement of rolling. Speed is measured at any basic part by means of pulse detector which speed is preset by drive. Value and sign of speed is also measured. Cross-section and weight of blank are taken into account and path, which should be passed by blank in case of absence of sliding, is calculated. The path is compared with the path calculated by pulse counter. Value of slide is determined by difference in two lengths. The latter is taken into account as correction for length calculated by pulse counter.

EFFECT: improved precision of measurement.

2 cl

Description

The invention relates to the field of instrumentation, and more particularly to methods for measuring the length of a rolling car.

A known method for measuring moving rolled products, including determining the position of the end of the rental relative to, for example, the cutting line or simultaneously determining the position of the front and rear ends using the required number of photodetectors installed along the measured area at certain intervals, the output signal of which has two values (dark light, zero unit). By processing these output signals, you can determine the desired length. (USSR author's certificate No. 1097895 MKI G 01 B 11/00 of 06/15/84, USSR author's certificate No. 1415039 MKI G 01 B 7/04 of 08/07/08, USSR author's certificate No. 1479818 MKI G 01 B 7/04 of 05/15. 89, Copyright Certificate No. 1663422 MKI G 01 B 21/00 dated 07/15/91, USSR Copyright Certificate No. 1188525 MKI G 01 B 11/00 dated 10/30/85).

This method of measuring the length of a rolling steel is implemented in devices that have high noise immunity, allow you to organize a self-test of the meter, provide good accuracy, but have a complex, cumbersome and expensive design.

. Кроме этого, к каждому фотоприемнику необходимо подвести кабель, содержащий, по крайней мере, три жилы. Суммарное количество проводников, идущих от фотодатчиков на приемные блоки, в этом случае будет составлять 600 единиц (200×3=600). Дополнительно к каждому излучателю также необходимо подвести два провода. Размещение такого количества аппаратуры в ограниченном пространстве весьма затруднительно, а в случае горячего проката потребуется еще и защита большого количества фотоприемников от нагрева их корпусов.For example, to measure the length of the workpieces in the range from 2 to 5 m with a measurement error not exceeding 15 mm, it is necessary to install 200 photodetectors, and in the case of cold rolled it is necessary to install 200 emitters on the opposite side

. In addition, a cable containing at least three wires must be connected to each photodetector. The total number of conductors going from the photosensors to the receiving units, in this case, will be 600 units (200 × 3 = 600). In addition to each radiator, it is also necessary to bring two wires. Placing such a quantity of equipment in a limited space is very difficult, and in the case of hot rolling, protection of a large number of photodetectors from heating their bodies will also be required.

There is a known method of measuring rolling stock, in which the measured length is divided into a number of base sections and the end position of the rental is determined using photodetectors and oppositely placed emitters installed along the boundaries of the base sections, and the measurement inside the base sections is carried out by means of a pulse sensor from the measuring contact roller, this path, the rental and the number of pulses at the output of the sensor during the passage of this path are interconnected. (I.A. Aronov, M.A.Sonkin "Devices for measuring the length of rolled products and pipes in the USSR and abroad" NIIINFORMTYAZHMASH, Metallurgical equipment, 1-68-13, M., 1968, p. 17, 40; "Instruments for automatic measurement of pipes and pipe products" Central Research Institute of Information and Technical and Economic Studies of Ferrous Metallurgy, Overview, Series 15, Issue No. 2, Moscow, 1974, p.24; Chelyustkin AB "Automation of rolling production processes "Moscow, Metallurgy, 1971, pp. 121-122, Fig. 44-45).

This method of measuring rolling stock is implemented in structurally simpler devices, since photodetectors are rarely installed along the length of the rolled steel, that is, their number is significantly reduced compared to the previous analogue, and the number of related equipment is also reduced. However, the measurement inside the base sections by means of impulse sensors from the contact roller leads to significant measurement errors and a decrease in the reliability of the measurement process, especially in the case of hot rolled products, since in this case the contact roller operates in severe thermal conditions (cyclic heating and cooling), and with a change in temperature, its dimensions change, which leads to measurement errors. Additionally, the measurement error increases due to slipping of the contact roller at the rental. In addition, if the range of rolled products changes, the implementation of the method is structurally significantly complicated, since a special design of the roller clamp is required, which allows you to quickly switch from one assortment to another, and in order for the roller not to be broken by moving workpieces, its clamp-spin must be synchronized with the movement of the measured workpieces.

A known method of measuring the length of the rental, adopted as a prototype, in which the measured length is divided into a number of base sections and determine the position of the end of the rental using photodetectors and oppositely placed emitters installed at the borders of the base sections, and the measurement inside the base sections is carried out using a pulse sensor with drive moving rental. (I.A. Aronov, M.A.Sonkin "Instruments for measuring the length of rolled products and pipes in the USSR and abroad" NIIINFORMTYAZHMASH, Metallurgical equipment, 1-68-13, M., 1968, p. 39, Fig. 12).

This method is implemented in devices that do not have the drawbacks described above, however, if it is used to measure the length of rolled metal moving along the roller table, that is, when installing a pulse sensor on the roller table drive, measurement errors significantly increase due to rolling slippage, which is a speed mismatch rolling motion and peripheral speed of the roller surface of the roller table. If the roller table accelerates, then the speed of the roller can be higher than the speed of the rolling movement, since the workpiece, due to its massiveness (inertia), continues to lie, and the rollers are already spinning under it. Speeds can only coincide in the case of slow and smooth acceleration of a non-massive and wide workpiece well adhered to the surface of the rollers. Thus, during acceleration, the pulse sensor can count either the correct length or the length greater than the correct one (but not less). When braking, the opposite phenomenon occurs: the rollers stop, and the inertia rolling continues to move. In this case, the pulse sensor can count either the correct length or a length smaller than the correct (but not large) one.

In addition, the aforementioned method of measuring the length of the rental does not diagnose the operation of the main elements of the length meter.

The problem solved by the invention is to increase the accuracy of the measurement by taking into account the possible slippage of the rental on the rolling table, as well as to increase reliability by providing a diagnosis of the operation of the main elements of the length meter.

This problem is solved as follows.

In the known method of measuring the length of a rolling car, in which the measured length is divided into a number of base sections and the end position of the rental is determined using photodetectors and oppositely placed emitters installed along the borders of the base sections, and the measurement inside the base sections is carried out by means of a pulse sensor from the drive to move the rental ACCORDING TO THE INVENTION, at each base portion, the speed determined by the drive, as well as the magnitude and sign of acceleration, are determined using a pulse sensor, except о take into account the cross section of the workpiece and its mass, calculate the path that must be traveled by the workpiece in the absence of slippage, and compare it with the path calculated by the pulse sensor, determine the slip value by the difference of these values and subsequently take this value into account as an adjustment to the length, counted by the pulse sensor, the correction being determined as:

+ Δ = f (a, s, m) - in the case of movement with deceleration, or as

-Δ = f (a, s, m) - in the case of movement with acceleration,

where f is a symbol of functional dependence;

a - acceleration of the drive;

s is the cross section of the workpiece;

m is the mass of the workpiece.

In addition, they organize a procedure for checking the meter’s operability by turning off / on the illuminators in the absence of a workpiece in accordance with the specified diagnostic procedure and analyzing the status of the photodetector outputs, fix the malfunction of the corresponding measuring paths in case of non-compliance, in addition, they constantly compare the base distance and the corresponding workpiece length, calculated pulse sensor, taking into account the error on slippage and in case of mismatch, they generate a signal or about a malfunction a certain photovoltaic path, or about a malfunction of the pulse sensor.

A method of measuring the length of a rolling rolled stock is implemented as follows.

The measured length is divided into a number of base sections and the position of the end of the rental is determined using photodetectors and oppositely placed emitters installed along the boundaries of the base sections, and the measurement inside the base sections is carried out using a pulse sensor with a drive to move the rental, while on each base section using a sensor pulses determine the amount of slippage and then take this value into account in the form of an adjustment to the length calculated by the pulse sensor.

The amount of slippage is determined as follows.

The rental speed is determined by dividing the path (50-60 mm) by its travel time and acceleration, calculating the speed difference in two adjacent sections (measurement time is the same) and dividing this difference by the measurement time. (The constant frequency of the pulses at the output of the pulse sensor is a constant speed. The frequency increases - acceleration (acceleration). The frequency decreases - deceleration (deceleration)).

Based on the calculations made determine the nature of the movement of the workpiece:

- without acceleration at a constant (measured) speed;

- with acceleration, the value of which is calculated and known;

- with deceleration, the value of which is calculated and known.

Next, consider the path traveled:

- ΔL = V × t - when moving without acceleration at a constant speed;

- ΔL = V × t + at ^2/2 - with motion acceleration;

- ΔL = V × t-at ^2/2 - when driving with deceleration.

The same lengths are determined using a pulse sensor. When driving at a constant speed, we believe that there is no slippage and ΔL = V × t (obtained by calculation) should coincide with the value calculated by the pulse sensor. The total length of the workpiece is determined by the addition of two quantities:

L _zag = L _bases. + ΔL,

where L _zag - the length of the workpiece;

L _bases - the distance between two photorelay;

ΔL is the distance calculated by the formula or determined by the pulse sensor.

When moving to the acceleration feel that the acceleration is constant and in the absence of slippage: ΔL = V × t + at ^2/2 (obtained by calculation) must coincide with the value counted pulser. If there is no coincidence and at the same time the pulse sensor has counted a large value, then we believe that there was slippage and we remember (in a special protocol for subsequent analysis) the acceleration and the workpiece data (mass and cross-section). If there is no coincidence and at the same time the pulse sensor has counted a smaller value, then we believe that either the corresponding photorelay is "knocked down" or the pulse sensor is faulty, or problems in the corresponding cable connections. In this case, we give the operator a warning message.

When driving with deceleration feel that the deceleration is constant and in the absence of slippage ΔL = V × t-at ^2/2 (obtained by calculation) must coincide with the value counted pulser. If there is no coincidence and at the same time the pulse sensor counts a smaller value, then we consider that there was slippage and we remember (in a special protocol for the subsequent analysis) the acceleration and the workpiece data. If there is no coincidence and at the same time the pulse sensor has counted a large value, then we believe that either the corresponding photorelay is "knocked down" or the pulse sensor is faulty, or problems in the corresponding cable connections. In this case, we give the operator a warning message.

The following should be especially noted. All (at least in metallurgy) modern automated process control systems (automated process control systems) (and the length meter is part of such a system) are built on the basis of programmable logic controllers (PLCs) and using personal computers (PCs). Those. Reception, processing, storage of information, development of control actions are carried out not by specialized computing and logic devices, but by universal PLCs and PCs.

By logical processing of the signals coming from the length meter, we find the dependence of slippage on acceleration and the workpiece data (its approximate mass and cross-section / area of its lower surface /). Data on the mass and cross section in the automatic process control system are always available. Acceleration values also do not lie in a wide range, but are selected on the basis of ensuring the necessary rate of transportation in a given section of the production line. The assortment of blanks is also not infinite. For a specific object in which the proposed solution is intended to be used, only two types of section and twenty possible lengths are specified. The real production situation is also favorable because the assortment does not change randomly, but some type of procurement is constantly going on for some time (days, weeks), then a planned transition to another type is carried out, etc.

Having found (using modern computer technology) the dependences of slippage on acceleration and the workpiece data (this may require only a few measurements), use these dependencies to adjust the measurement results, determining the correction as:

+ Δ = f (a, s, m) in the case of motion with deceleration, or as

-Δ = f (a, s, m) in the case of movement with acceleration,

where - f is a symbol of functional dependence;

a - acceleration of the drive;

s is the cross section of the workpiece;

m is the mass of the workpiece.

Slip can also be determined by the “semi-manual” method, i.e. comparing the values found by the length meter and then checked, for example, using a tape measure. Data on the parameters of the workpiece, accelerations and the length in the system are saved. Then, manually entering the corrections defined in this way into the system, they can be automatically taken into account when measuring the length. But it’s more modern to do this procedure with the help of existing computer technology, i.e. as in the present invention.

As a result of taking into account the correction described above, an increase in the measurement accuracy is achieved, and this is achieved without the use of any special devices, but due to a more complete use of the opportunities provided by the necessary equipment.

In addition, they organize the procedure for checking the meter’s operability by turning off / on the illuminators in the absence of a blank in accordance with the specified diagnostic procedure and analyzing the status of the outputs of the photodetectors, fixing the malfunction of the corresponding measuring paths in case of non-compliance, in addition, they constantly compare the base distance and the corresponding blank length, calculated by the pulse sensor taking into account the error on slippage, and in case of mismatch, they generate a signal or about a malfunction and the particular photoelectric tract or a pulse sensor malfunction.

The proposed actions are aimed at organizing a constant (during operation) check of the meter's operability. This check allows you to almost immediately detect a failure (or a noticeable malfunction) in the operation of the main elements of the length meter. Indeed, if in the absence of a blank all the illuminators are turned on, then the output of all photodetectors should have a "light" signal, if all the illuminators are turned off, then the output of all photodetectors should have a "dark" signal. A violation of this dependence indicates a malfunction in the path in which such a violation is detected. This situation can be immediately reported to the maintenance personnel with a specific path and reason, for example: “Caution! At the output of the 5th PD, the constant signal is“ dark. ”Then it is no longer difficult to determine what happened on the spot: if the illuminator does not turn on, then and faulty, if the illuminator turns on and its optical axis is not knocked down, then the photodetector is faulty.

If necessary, you can organize more complex diagnostic procedures, for example, the alternate inclusion of even / odd channels; running "unit"; or running zero. The speed of modern photosensors allows you to organize such a procedure without additional time in the technological gap between two adjacent measurements.

In addition to the above procedure for checking the meter’s operability, another procedure is organized based on the obvious fact that when moving a workpiece by the amount of the base distance (measured by signals from two adjacent photosensors), the same value (during the passage of this base distance) should be calculated and pulse sensor. The amount of slippage can be taken into account as described above. If these values (determined by the photorelay and counted by the pulse sensor) do not match (for example, the difference is greater, for example, 4 mm), then the meter will fail in this section. If a failure is detected at the next base site, then most likely the path for measuring the pulse sensor is faulty and this situation can be immediately reported to the service personnel with the reason: "Warning! The pulse sensor in the section 5-6 / 45 cm / counted a value of 27 cm; on a plot of 6-7 / 35 cm / counted a value of 23 cm. " If the failure occurred only in any one area, then this situation is also recorded and reported to the operator. If, during the measurement of the subsequent workpiece, a malfunction is detected in the same section, then most likely they are mechanically knocked down or a malfunction appears in one of the pair of photosensors forming this base section. This situation can also be reported to the operator.

The proposed diagnostics allows you to almost immediately detect a malfunction or frequent malfunctions of the main elements of the meter and even helps to identify a failed (malfunctioning) element. For production personnel, such diagnostics is of lasting importance, since it allows to significantly simplify troubleshooting and localization of malfunctions, which leads to a significant reduction in downtime, and as a result to an increase in productivity at this production site.

For the organization of diagnostic procedures, no additional equipment is used, but the elements of the meter itself are used. Diagnostics can be implemented either using a programmable logic controller or a personal computer, which are used without fail when building modern automation systems.

Claims (2)

1. The method of measuring the length of the rental, in which the measured length is divided into a number of base sections and determine the position of the end of the rental using photodetectors and the oppositely placed emitters installed on the borders of the base sections, and the measurement inside the base sections is carried out by means of a pulse sensor from the drive to move the rental, characterized in that at each base section using a pulse sensor determine the speed specified by the drive, as well as the magnitude and sign of acceleration, in addition, take into account the cross section for the forgings and its mass, calculate the path that the workpiece must pass in the absence of slippage, and compare it with the path calculated by the pulse sensor, determine the slip value by the difference between these values and subsequently take this value into account as an adjustment to the length calculated by the pulse sensor , the amendment is defined as + Δ = f (a, s, m) in the case of motion with deceleration, or as -Δ = f (a, s, m) in the case of movement with acceleration, where f is a symbol of functional dependence; a - acceleration of the drive; s is the cross section of the workpiece; m is the mass of the workpiece. 2. The method according to claim 1, characterized in that they organize the procedure for checking the meter’s operability by turning off / on the illuminators in the absence of a workpiece in accordance with the specified diagnostic procedure and analyzing the status of the photodetector outputs, fix the malfunction of the corresponding measuring paths in case of non-compliance, in addition, they constantly compare the base distance and the length of the workpiece corresponding to it, calculated by the pulse sensor, taking into account the error in slippage, and in case of mismatch form a signal either about a malfunction of a particular photovoltaic path, or about a malfunction of a pulse sensor.