DE2040084A1 - Comparison system - Google Patents

Description

COMPARISON SYSTEM The present invention relates to a comparison system for luminous objects, consisting of two photoelectric elements, in particular for cutting the front and rear ends of red-hot steel strips during of the rolling process.

The present invention is particularly in the field of steel rolling applicable. In the case of steel rolling, a hot block is generally assumed, which is rolled out in several process steps to the end product.

It often happens that during the. procedural steps carried out first the front end of a steel band is deformed. However, this causes an uneven load of the rollers performing the finishing treatment, whereby the latter can be damaged, which can result in an interruption in operation can. In order to avoid this, it has hitherto been customary for the operator to the rolling steel strip was visually observed and the deformed one by means of a cutting machine Cut off the end of the steel band. However, this had the disadvantage that very often either Too much or too little of the steel strip was cut, either resulted in increased waste or damage to the finished rolls.

The aim of the present invention is to create a comparison system, that does not have this disadvantage and that automatically cuts off the material to be rolled Allows steel band in the right place.

According to the invention this is achieved in that on the photoelectric Elements images of a part of the luminous object are depicted, whereby an output signal results, which is at least the shape, the temperature or the Intensity of the illumination of the image corresponds, and that a comparison circle is provided which detects the output signals of the photoelectric elements, where those parts of the luminous object whose images are on the photoelectric Elements are formed in terms of shape, temperature and / or intensity the lighting are compared with each other.

The comparison device according to the invention is very simple and reliable, by measuring the shape, temperature, or intensity of light. It will a pair of the same temperature having subregions with each other compared, with either the front part and the middle piece or the middle piece and the end of a luminous band - for example, one that is red hot Steel strip - during rolling in terms of shape, temperature or the intensity of the illumination are subjected to a measurement. The comparison device can be designed in such a way that an automatic Shutdown of the same takes place.

Preferably there are two photoelectric elements with corresponding Connected amplifiers, which have a variable gain.

An advantageous embodiment of the invention is characterized in that that in the direction of the movement of the luminous object the following elements the following are provided: a) three photoelectric elements arranged one behind the other, b) at least two sensors, of which the first in the area of the third photoelectric Element is arranged, c) end detectors, which the ends of the object to be measured determine, wherein d) a comparison circuit the output signals of the photoelectric Elements for the front end part of the article and the output signals of the second and third photoelectric element for the rear part of the object compares.

Further details of the invention are given below with reference to a Exemplary embodiment will be explained and described in more detail, with reference to the attached Drawing is referred to. FIG. 1 shows a block diagram of the comparison device according to the invention, Figure 2 is a graphical representation of the light-sensitive surface depending on the short-circuit current within the scope of the present invention used solar cell; Figures 3a and b are schematic perspective and side views, respectively the comparison device according to the invention, which in connection with a steel rolling process is usable.

Figure 4 is a block diagram of one embodiment of the invention in conjunction with the arrangement shown in Figure 3; Figure 5 is a more detailed circuit diagram the comparison device shown in Figure 4; Figure 6 a combined block and a circuit diagram of a modified embodiment of the invention for steel rolling processes; FIG. 7 shows a view similar to FIG. 6 of a further modified embodiment the invention; Figure 8 is a circuit diagram of a scanning device for in Figure 6 and 7 shown arrangement; Figure 9 shows a modified embodiment the scanning device shown in Figure 8; Figure 10 is a schematic circuit diagram of a circle for driving the scanning device shown in FIG. 9 and FIG 11 is a truth table of the flip-flop circuit shown in FIG.

In the various figures, the same reference symbols denote the same or similar items.

In Figure 1, a basic arrangement of the invention is shown. This arrangement consists of a pair of photo elements 1 and 2 - for example Solar cells - on which the pictures 3 and 4 of luminous to be compared Objects are in focus. These photoelectric elements 1 and 2 result in corresponding the area of the images output currents which are conducted to measuring circuits 5 and 6. The outputs of these measuring circuits 5 and 6 are connected to a comparison circuit 7, which emits an output signal at its output terminal 6.

The solar cells used as photoelectric elements 1 and 2 weisell has a current characteristic depending on the light receiving surface, see above as shown in FIG. The abscissa of this figure corresponds to the logarithmic one Value of the light receiving area in square millimeters, while the ordinate indicates the logarithmic value of the short-circuit current in microamps, where as Parameter the light intensity is given in lux. Based on Figure 2 one can recognize that the short-circuit current of the solar cells is directly proportional to the light receiving area and intensity of lighting is. In other words, the photoelectric Elements 1 and 2 produce an output current depending on the area and intensity of the Illumination of the object focused on the same.

Since the output currents of the photoelectric elements 1 and 2 with the help corresponding current measuring circuits 5 and 6 determined and in a comparison circle 7 are compared with each other, the output signal at terminals 8 results in a electrical quantity, which is the difference in size and the difference in intensity corresponds to the lighting or the temperature between the objects to be compared.

While the present invention has a wide variety of uses it is particularly useful in connection with steel rolling processes; consequently it is intended to be described below in connection with such methods.

Figures 3a and b explain the manner in which the present Invention is applicable in connection with a steel rolling process. Figure 3 shows a red-hot steel strip 9, the front end of which is a pair of rollers (not shown) just left. The front end just comes into the field of view of a focusing lens 11. The steel belt 9 moves at a predetermined speed in the direction of the arrow shown in Figure 3a. That emitted from the front end of the steel belt 9 Light comes through the lens 11 - as indicated by the line 10 is - focused, so that on the comparison device designed according to the invention 12 results in an image 9 '.

The comparison device according to the invention is preferably designed in such a way that as shown in FIG.

According to Figure 4, the measuring unit SU has a plurality of elongated photoelectric elements 13 to 17, which are parallel to each other in such a way are arranged so that the longitudinal axes according to the arrow of Figure 4 perpendicular to the direction of movement of the image 9 'run. The photoelectric elements 13, 14 and 15 correspond the photoelectric elements 1 and 2 shown in Figure 1, while the rest photoelectric elements 16 and 17 for another use to be described later to serve. Assume that the photoelectric elements 13 to 17 are solar cells are as they have already been described in connection with FIG. It can however, other types of photoelectric elements can also be used.

As shown in FIG. 3, the measuring unit SU also has three hot metal sensors 18, 19 and 20, which run along the longitudinal axis of the sliding Image 9 'are arranged. The sensors 18 and 19 are on both sides of the arranged in parallel photoelectric elements 13 to 17, while the Sensor 20 is arranged further downwards in the direction of the movement of the image 9 '. The significance of this sensor 20 will be described below.

The photoelectric elements 13, 14 and 15 are with one high input impedance and high gain amplifiers 21, 22 and 23 connected, while the remaining elements 16 and 17 with corresponding Amplifiers 24 and 25 are connected. All of the amplifiers 21-25 are preferred provided with feedback loops and identical in terms of their construction.

The amplifiers 21, 22 and 23 form the measuring circuit shown in FIG 5 and 6.

While a red-hot steel band in the direction of the arrow from figure 4 is moved, an image is formed on the photoelectric element 15 first and then on the photoelectric element 17. Before the photoelectric Element 17 receives light from the steel band 9, the relay contacts 30 and 32 connected to one another, so that a gate circuit 26 is controlled, the input of which is directly connected to the amplifiers 24 and 25. The sensors 18 and 19 on the one hand and the amplifier 21 via the relay contacts 31, 32 and the amplifier 23 via relay contacts 30 and 32, on the other hand, are connected to gate circuit 26.

Another advancement of the image 9 'of the steel belt 9 - according to FIG 4 up - causes the image to also hit the photoelectric element 14 falls. At this time, it indicates the photoelectric elements 15 or 17 formed image to maximum width, whereby the deformed front end is not more is perceived. The output currents of the photoelectric elements 14 and 15 are fed to a comparison circuit 27 via the amplifiers 22 and 23. This Comparison circle 27 corresponds the comparison circle shown in FIG 7. Since the photoelectric elements 4 and 5 are solar cells, the output currents are - as already described - proportional to the illuminated area respectively.

the intensity of the illumination of the sections of the photoelectric Elements. Provided that the steel strip 9 has the same temperature everywhere it can be assumed that the parts of the image have a constant illuminance exhibit. Since the photoelectric elements 14 and 15 are elongated and across the width of the transported steel strip 9 lie, the output signals are this photoelectric elements and consequently the amplifiers 22 and 23 proportionally the width of the corresponding sections of the steel strip 9.

The output signal of the amplifier 22 is now sent directly to the comparison circuit 27 supplied, while the output signal of the amplifier 23 through the now connected Relay contacts 30 and 32 are also passed to this comparison unit 27. In. In this comparison unit 27, both output signals are thus compared with one another. When the comparison unit 27 determines that the output of the amplifier 22 is the same as that of the amplifier 23, a time delay circuit 49 becomes a control signal fed; after a certain time delay this control signal arrives at a Cutting device shown in Figure 3b, which in terms of flow direction the comparison device 12 is arranged. This control signal is the Cutting device actuated, causing the deformed front end of the red-hot Steel band 9 is cut off.

By appropriately setting the amplification factors of the amplifiers 22 and 23 - for example by adjusting the gain of the amplifier 23 to 90% of the amplification factor of the amplifier 22 - is with the help of the comparison circle 27 set the point in time at which the width of the image 9 'on the photoelectric Element 14 is 90% of the width of the image 9 'formed on element 15. The cutting device 50 can thus be operated on that part of the steel belt 9, the width of which in about 90% of the maximum width of the steel belt, causing the deformed front Part of the steel band is separated from the rest.

The steel belt 9 is then - according to FIG. 4 upwards - moved further, to the front end, the face area of the photoelectric elements 15 and 17 leaves. At this time, the photoelectric elements 16 and 17 and 16 operate the associated amplifiers 24 and 25 with the gate circuit 26 to the presence of the rear end of the steel strip 9 in the field of view of the measuring unit SU. The relay contact 32 is then instead of the relay contact 30 with the relay contact 31 connected so that the comparison unit 27 the output signals of the photoelectric Compare items 13 and 14 with each other.

At the same time, the relay contact 35 separates from the relay contact 33 and uses the relay contact 34, as will be described below will.

The described in connection with the front part of the steel band 9 The process is then repeated in connection with the rear end piece. Similar like the amplifier 23 can also be used by the amplifier 21 with its gain factor be set to 90% of the gain of amplifier 22 to avoid the deformed to remove the rear end of the steel belt 9, the width of which is approximately 90% of the corresponds to the maximum width.

The hot metal sensors 18, 19 and 20 respond to the presence a red-hot steel strip 9 in the field of view of the measuring unit SU to the corresponding Relay contacts not shown to close, so that individual signal result. These signals, together with the output signals of the amplifier 24 and 25 in the gate circuit 26 used to determine when a particular Steel band 9 is processed. The comparison circuit 27 thus gives a control signal for the steel strip 9 only when the measuring unit SU is the front or rear Part sees; accordingly, the cutter 50 is prevented from being erroneously to be served as long as the middle part of a steel belt a below the measuring unit located. For this purpose, the hot metal sensors 18, 19 and 20 are equipped with a Fault detection circuit 28 connected, which is also output signals of the gate circuit 26 receives. This fault detection circuit is used to detect malfunctions in the system 28 is also connected to a fault detection circuit 2a. The latter fault detection circuit 29 is on the input side with the gate and comparison circuits 26 and 27 and consequently connected to the amplifier 24, while on the output side - as shown in FIG. 1 is shown - is connected to terminal 8.

The switching arrangement shown in Figure 4 can preferably according to the switching arrangement of Figure 5 formed be in which same Reference symbols denote identical or corresponding components of FIG. As shown in Figure 5, the photoelectric elements or Solar cells 13 to 17 are connected to amplifiers 21 to 25, which have a high input impedance exhibit. Because of the high amplification factor these amplifiers 21 to 25 can Input potential be essentially zero, feedback resistors R being provided whose indices correspond to the corresponding amplifiers. On these amplifiers 21 to 25 thus result in electrical output signals which the short-circuit current of the respective photoelectric elements 13-17 multiplied by the resistance correspond to the feedback resistances. Each of the feedback resistors - for example the feedback resistor R13 - is in parallel with a capacitor - For example a capacitor C13 - arranged to avoid instabilities of the corresponding Amplifier 21 to 25 to eliminate which by a greater length of the coaxial Connection cables to the amplifiers 21 to 25 are required. About differences in sensitivity of the photoelectric elements 13, 14 and 15 are the outputs the amplifiers 21, 22 and 23 are connected to respective potentiometers 50, 51 and 52. Appropriate setting of this potentiometer results in the presence of images of the steel strip appearing on the photoelectric elements 13, 14 and 15 9 of the same width on the output lines 79, 80 and 81 of the potentiometers 50, 52 and 51 voltages of the same magnitude. The output line 80 is with an inverter and amplifier 22 'connected, the output side a potentiometer 53 and a with the movable scanning point of the potentiometer 53 and the Input connected feedback resistor R22. The potentiometer 53 is used to determine the ratio of the maximum width to the width to be cut front and rear ends of the steel belt 9. The output of the amplifier 22 ' is connected to a comparator 27, which is designed as a feedback amplifier is, with a resistor 61 and the amplifier 21 and 23 via corresponding relay contacts 30, 31 and 32 are connected to the comparator 27. The resistor 62 is there the same size as the resistor 61. The amplifiers 24 'and 25' are in the same way on the one hand via resistors 64 and 66 to the amplifiers 24 and 25, on the other hand via the mentioned relay contacts and resistors 63 and 65 with the amplifiers 21 and 23 connected. Zener diodes are attached to the corresponding amplifiers 26, 24 'and 25' 67, 68 and 69 connected to the voltages occurring on the output side between zero and the Zener voltage.

Once the hot metal sensor 18 is the front end of a red-hot Steel belt 9 determines which in the direction of a final treatment resulting Roller pair is performed, close its contacts 18 '. By closing the Contacts 18 'becomes the base electrode of a transistor 77 through one through elements 70 to 75 formed circle positively biased, whereby interfering signals are rejected and prevents a multiple operation due to relay contact rattling is triggered. The transistor 77 is then saturated, so that on one line 82 a zero potential occurs. The line 82 therefore receives a logical one Zero value. Since the hot metal sensor 19 does not yet see the steel strip 9, the remain appropriate Relay contacts 19 'open. As a result, the associated Line 83 is held at a positive potential or at a logic value 1. The NAND gates 90 and 91 connected to lines 82 and 83 thus receive at their respective outputs 84 and 85 values of ZERO and ONE, respectively. To the same At the instant, the two lines 94 and 95 have logical values of ONE and ZERO on.

The lines 84 and 85 are with the setting and the reset terminal an Eip-Flop 92 connected, which is switched in its set state, as soon as a zero value is applied. Under these circumstances, the flip-flop 92 becomes in brought its set state, so that a value of ONE results at the output 86. This causes the base of a transistor 93 to be positively biased, thereby saturating the transistor. As a result, the relay winding 87 is energized, whereby their contacts 32 and 35 come into contact with contacts 30 and 33.

When moving the steel belt 9 is on the photoelectric Element 15 and then an image 9 'on the photoelectric element 17. Both photoelectric elements 15 and 17 are connected to respective amplifiers 25 and 23 of opposite polarity connected. The outputs of these amplifiers 25, 23 are fed to the amplifier or comparator 25 'via resistors 66 and 65, resistor 66 being smaller than resistor 65. When on the photoelectric Elements 15 and 17 images of the same width occur, the comparator 25 results a positive signal at its output. This results in 88 on line a signal with the value ZERO, while on line 89 a signal with the value ONE occurs.

A further movement of the steel belt 9 causes the photoelectric Element 14 sees a picture of the deformed front end portion of the steel belt, so that at the amplifier 22 a negative output signal occurs. On the photoelectric Element 15 then creates an image of the part of the steel strip 9 of maximum width. This results in a positive voltage at the output of the amplifier 23. The output signals of the amplifiers 22 'and 23 are then passed through appropriate resistors 61 and 62 are fed to the comparator 27.

Since the amplifier 22 'has a lower output signal first as the amplifier 23, the comparator 27 gives a zero signal at its output away. As soon as the deformed front part of the steel belt 9 continues to move forward thereby the width of the image appearing on the photoelectric element 14 approaches the maximum width, the output of amplifier 22 'becomes one certain point in time greater than that of the amplifier 23. The comparator then generates 27 a positive output signal. The point in time at which the output signal of the Comparator 27 changes its polarity depends on the ratio of the voltage division through the potentiometer 53. Assume that this ratio is i%, - this ratio being 90% in the embodiment of Figure 4 - so the output of the comparator 27 becomes positive as soon as the width of the image of the steel strip on the photoelectric element 14 reached i% of the maximum width. This has the effect that at output 100 of a NAND gate has a zero value occurs, whereby the output 101 of a flip-flop changes from a ONE value changes a ZERO value, thereby turning off transistor 102. To this Point in time and thereafter, a capacitor 105 charges via resistors 103 and 105 on. As soon as the capacitor 105 has a higher voltage than the Zener voltage Having Zener diode 106, a transistor 107 receives on its base-emitter path a positive bias, which is thereby saturated. This has the consequence that the collector potential drops to a zero value. The associated flip-flop will then retriggered so that a value ONE appears on output line 101. From this it follows that the other output of this flip-flop gives a pulse, the duration of which corresponds to the time interval during which the capacitor 105 is charged up to the Zener voltage of the Zener diode 106. Accordingly, form the transistors 102 and 107 and the associated switching elements form a timer circuit.

Since the NAND gate 99 at its inputs via lines 89 and 94 positive signals corresponding to logic values ONE receives, the transistor 109 saturated as long as the output 108 has a signal with the logic state ONE having. This causes the connected to the collector of transistor 109 Relay winding remains energized so that contacts 111 and 112 are connected together are. This closing of contacts 111 and 112 connects to contact 112 connected output terminal 115 via the normally closed relay contacts 124 and 125 with a different output terminal 116. Both terminals 115 and 116 are with the control input of the cutting device 50 connected. As a result the connection of terminals 115 and 116 causes the control to be unlocked, until the deformed end piece of the steel strip 9 is cut off.

When the front end of the deformed part of the steel belt 9 is relatively is sharply pointed, so that the width of the image on the photoelectric Element 14 does not reach the value% of the total width before the image on the photoelectric Element 16 is formed, then the amplifier 24 'is connected via a NAND gate 117 operated so that the line 100 receives a ZERO value, which is a cutting signal triggers. The output terminals 115 and 116 are thus described in the above Way connected to each other so that the deformed front part of the steel belt 9 is cut off.

As soon as the steel strip 9 is transported further and through the hot metal sensor 19 is scanned, the relay contacts 19r are closed, creating a transistor 76 is saturated in the same way as with respect to the hot metal sensor 18. This causes all lines 94, 95 and 96 to be NULL. this ensures that despite the presence of a corresponding output signal of the comparator 27 a signal with a ONE value or a cutting signal for the Steel band 9 can occur.

As a result, it is prevented that even during an intermediate piece of the steel strip 9, a cutting signal is generated.

The steel belt 9 will then continue to be transported, whereupon the rear end part leaves the area of the hot metal sensor 18, which is an investigation of the end part. At this point in time, the sensor 19 continues to see that Steel band 9 so that the output line 84 to the NAND gate 90 has a ZERO state results, while lines 95 and 96 each result in a ONE state. As a result flip-flop 92 generates a ZERO state. The transistor 93 is then switched off, whereby the relay winding 84 is de-energized. As a result, the contact 32 with the contact 31 and the contacts 35 connected to the contact 34, so that the comparator 27 is operated to generate a signal corresponding to the width of the image of the Steel strip 9 on the photoelectric element 14 with a signal accordingly the width of the image of the steel strip 9 on the photoelectric element 13 increases to compare.

The steel belt 9 continues to run forward until the image of the rear Part comes out of the area of the photoelectric elements 17. This will make that The output of amplifier 25 'is reduced to zero so that lines 88 and 97 have a potential corresponding to a ONE state. The further movement of the steel belt causes the rear end portion to hit the photoelectric element 14 is focused. The width of this image focused on element 14 increases gradually until the valueoC% of the maximum width is reached. At this time the output signal of the comparator 26 decreases from a positive value to one Zero value. As a result, the signal present on line 100 changes from a value ONE to a value NULL, so that the matching flip-flop emits a signal corresponding to a value ONE at its output 108. To this At this point in time, lines 88 and 95 are held ONE, making a NAND gate 98 outputs a ZERO value, which saturates transistor 110, causing a closure which results in contacts 113 and 114. This is due to the closure of contacts 113 and 114 caused signal is via terminals 118 and 119 and the normally closed relay contacts 126 and 127 of the control of the not shown in Figure 5 Cutting device fed, with the result that the end piece of the steel strip 9 is cut off.

The NAND gate 120 represents errors or malfunctions of the system fixed when red-hot steel strip detected by a probe sensors 18 and 19 9 should also address the photoelectric elements 16 and 17.

If one of these elements 16 and 17 does not lock the steel band should while the steel belt below the detector 12 with the photoelectric Elements 16 and 17 and the hot metal sensors 18 and 19 is - which is a faulty one Functionality or a disturbance means -, then generates the NAND gate 120 on a signal on its output line 121, which puts the flip-flop in its set State is brought, wherein the connected to the flip-flop transistors 121 and 122 are saturated. As a result, the corresponding relay contacts loosen 124 and 126 from the corresponding relay contacts 125 and 127, whereby the cutting signal is prevented from reaching the cutting device via clamps 115 and 116 or 117 and 118 50 directed / to be. /to Any disruption of work and functionality of the system is determined by a steel band 9 from both the detector elements 16 and 17 as well as the sensors 18 and 19 must be determined. this means in other words that - as long as the hot metal sensors 18 and 19 the steel strip 9 do not see - the photoelectric elements 16 and 17 also no steel band should see. As long as there is no steel band 9 under the detector elements 16 and 17 and the sensors 18 and 19 is present, a photoelectric element 16 or 17 see a strip 10, which is also a malfunction of the system or a faulty one Operating mode means. Under these circumstances, the NAND gate yields 120 as well an output signal with a NULL value. The one above then repeats itself Paragraph described sequence, whereby the cutting signal is prevented to the Control device of the cutting device 50 to be guided.

The hot metal sensor 20 is used to determine whether another steel strip 9 follows the steel band that has already been determined. In the presence of a subsequent one Steel strip, the output 121 of the NAND gate 120 is locked in the ONE state, whereby a closure of the contacts 124 and 125 'and the contacts 126 and 127 ensured will. As a result, such a disruption has no further consequences.

It should be understood that a set of relay contacts are similar the relay contacts 123 and 1214 can be provided to an alarm lamp or a To operate the buzzer.

While the photoelectric elements 13, 14 and 15 respectively the The previous description is elongated solar cells, so it should be understood be that they can also be designed in a different spatial configuration, as described in the embodiment shown in FIG. According to this Figure 6 is a plurality of small photoelectric elements 130a, b, n ~ side by side in a direction perpendicular to the direction of movement of the steel strip 9 arranged at a certain distance, creating a first linear arrangement of the photoelectric Elements 130 results. At a certain distance from this is another number of small photoelectric elements 131a, b, ... n arranged in the same way, whereby another set of photoelectric elements 131 results. The two Arrays 130 and 131 are substantially parallel and facing an equal number of elements. The small photoelectric elements / from same construction, where the / are individual elements of the two arrangements are arranged in alignment with one another. A third linear array of photoelectric Elements can also be parallel and at a certain distance from the second electrical Arrangement 131 can be arranged in accordance with the arrangements of Figure 4, if so desired should be. Similar to the arrangement of FIG. 4, FIG. 6 shows a pair of photoelectric elements 16 and 17 on the outer sides of both assemblies 130 and 131 arranged. It is assumed that the arrays of solar cells exist.

The photoelectric arrangements 130 and 131 are on the output side connected to individual scanners 134 and 135. Both scanners are of the same construction, so that in the following only a single scanner 134 with reference to FIG figure 8 should be described.

According to Figure 8 is a plurality of N-channel field effect transistors 134a to n arranged parallel to one another. These transistors forming the scanner 134 each have a source electrode, each with different photoelectric Elements 130 a, b, ... n of the first arrangement 130 are connected, the other Ends are laid to earth.

Furthermore, the gate electrodes are connected to the respective gate terminal 180a, b, ... n connected, while the drain electrodes are connected to a common output terminal 175 are connected.

As long as the gate terminals 180a, b, ... n held at negative potential a series of pulses a, b, ... n are applied to them in sequence, the output signals of the photoelectric elements 180a, b, n of the first arrangement to feel. The output signals then become the common output terminal one after the other 175 supplied. The output signals of the second array 131 are sequentially a common output terminal 177 in the same way via field effect transistors 135a, b, ... n supplied.

The scanner 134 can have the configuration shown in FIG. 9, where like reference numerals denote the same elements of Figure 8 #. the photoelectric elements 130a, b, ... i, - the number of which is equal to i - result Output signals successively via corresponding field effect transistors 1314a, b, ... i a common amplifier provided with negative feedback 181 are supplied. In this way, each group becomes i photoelectric elements - for example the element no. ti + 1) - via no. 2i to one Amplifier coupled which is identical to amplifier No. 181a. Figure 9 only shows the first amplifier 181a and the j-th amplifier 181i. The amplifiers 181 have in each case field effect transistors 190a ... i, which have corresponding feedback resistances 192a ... i are connected so that the corresponding input signals are only amplified when the associated transistor 190 is in its off state. The outputs of the amplifiers 181d ... i are via corresponding semiconductor diodes 193a ...

1931 fed to a common feedback amplifier 193, in to which the output signals are added. The resulting sum of the output signals is fed to an output line 175.

The arrangement shown in Figure 9 can have the number of i x i - Scan inputs, with i and 1 each being a number of separate driver pulses are. The pulse generator circuit shown in FIG. 10 can preferably be used for this purpose be used. A square pulse generating circle 197, 198 is with a plurality - in this example i - connected by flip-flops 195a, b ... i. The producer group is on the one hand via a line driver or a NAND gate 199 with a time terminal T of parallel loops 195a, b ... i on the other hand via a further line driver or a NAND gate 200 connected to a return terminal R. The i th flip-flop 195i is via a line driver or a NAND gate 202 with a parallel connection connected by flip-flops 196a, b .. i.

The flip-flops have a truth table, just like them is shown in FIG.

During operation, terminal 201 is at positive potential held, whereby the NAND gate 200 outputs a zero potential ,. through which the Flip-flops 195a to i and 196a to i are reset. In the deferred State, the Q terminals of the flip-flops are brought to a positive potential, while the Q-terminals then have a zero potential. The ones with the Output terminals connected to flip-flops are thus switched in such a way that the output terminals 181a a zero potential and the output terminals 181b to i a negative potential have, while the output terminal 191a has a negative potential and the output terminals 191b to 191i have a zero potential. It should be noted that the output terminal 181a with the gate terminals lBOa, 180.1802i + 1 for the transistors 180a, 180i + 1, 1802i + 1 and terminal 181i is connected to gate terminal 180l, 1802i + 1 ..., while the output terminal 190a with the gate terminals 190a, 190i + 1, 1902i + 1 for the transistors 192a, 192i + 1, 1922i + 1 and the terminal 19li with the gate terminals l90iX 1902i, 190 is connected. The flip-flops are in the reset state the transistor 134a is accordingly in its on state, during the Transistor 192a is in its off state. This causes in the with the Output of the photoelectric elements 130a connected scanner 134 that at the Output terminal 175 a readout takes place.

When the reset terminal 201 changes from the positive value to a zero potential is decreased, the NAND gate 200 gives a positive potential, so that the pulse generating circuit 197-198 begins to oscillate. The time signal of this oscillating Circle becomes the flip-flops 195 of the time terminal via the linear driver or the NAND gate 199 T supplied. Once the output voltage of NAND gate 199 is down from its positive Value drops to zero, the Q terminal of the flip-flop 195a changes from its positive Value to a zero value while the Q terminal of flip-flop 195b is down from its zero value rises to a positive potential.

This causes the potentials at terminals 181a and b to be negative or become zero. At this point, transistor 134b is in its ON state and transistors 134a, c ... n in their OFF state during the Transistor 192a in its OFF state and transistors b, c n in their ON state are. This enables the output of the photoelectric element 130b is read out at the output terminal 175 of the scanner 134. Talk this way the flip-flops respond to the occurrence of successive timing signals; the flip flops are thus triggered until the output terminal 181i has a zero potential and the Output terminal 181a to h has a negative potential, whereupon the signal of the Photo of electrical element 130i is read out.

Then the next time signal comes to the flip-flops. This causes the potentials at terminals 181a and 181b through i to be zero or negative while the flip-flops 196a and b are triggered at the same time will. As a result, a zero potential occurs at terminal 191a, while the Terminal \ -19lb receives a negative potential, whereby the transistor, not shown 192b is turned off. This enables the scanner 134 to read the outputs of the photoelectric Elements 130i reads at its terminals 175, whereupon the above-described Process repeated.

Based on the preceding description it can be seen that the driver circuits of Figure 10, the number of which is i + i, a number of i + i input signals can feel.

Reference should again be made to FIG. 6 below.

It is assumed that a picture 9 'of a red-hot steel strip 9 is to be read, the steel band - according to Figure 6 upwards - so long is transported until it is detected by the photoelectric element 17.

Under these circumstances, the photoelectric element 17 is on Amplifier 151 connected, which emits a positive potential, whereby the output 152 of a NAND gate is changed from a value ZERO to ONE.

The image 9 'of the steel strip 9 continues to migrate, so that it is of the second and first photoelectric assemblies 131 and 130 is detected. As a result the scanners 134 and 135 are operated in the manner already described, wherein an output signal of ONE value only from those photoelectric elements is read, which have corresponding parts of the image. This results in output waveforms as represented by reference numerals 164 and 165. These waveforms 164 and 165 are supplied to counters 136 and 137, which are common Have input terminal 168.

The input terminal 168 receives a control signal 166 of the same frequency as the signal to drive the scanner so that counters 136 and 137 count the number of the pulses emitted by the samplers 134 and 135 count, and only while of the positive wave ranges of the output signal from these samplers. The counters 136 and 137 are connected to a subtractor 138, through which during a complete sampling at samplers 134 and 135 is a difference in counts both counters 136 and 137 is detected. The difference in the count of the difference calculator 138 is fed to a comparator 139 via an input terminal, in which a A comparison is made with a reference width that of the other input terminal 140 is fed. The comparator 139 is designed such that when a deformed front end of one below the photoelectric assemblies 130 and 131 Passed steel strip 9 has an output signal depending on the output of the Difference former 138 is output with respect to the reference width.

As shown in Figure 6, the output signals the samplers 134 and 135 to the reset terminals corresponding flip-flops 141 and 143 supplied. The flip-flops 141 and 143 respond to the presence of signals at the outputs of the respective scanners 134 and 135, so that by their position One output signals appear on output lines 142 and 144.

The flip-flops 142 and 143 have a common reset terminal 145 to which a formed by the falling edge of a pulse 162 Pulse is supplied.

The pulse 162 is developed after each completion of a scan cycle. A pulse corresponding to the leading edge of the Pulse 167 supplied.

At the point in time at which, consequently, a measured difference in width of a given image falls below the reference width difference, the Line 100 generates a ZERO signal, as a result of which via a NAND gate 99 a cutting signal is generated in the same way as already described in connection with FIG has been. The elements generating the cutting signal are thereby through the same Reference numerals denote the same as the corresponding components from FIG. 5.

After the image 9 'of the steel belt 9 on the photoelectric element 16 has been thrown, an amplifier 150 connected to it gives a positive Potential at its output, causing lines 152 and 153 to go to the ZERO state to be brought. Accordingly, the NAND gates show 99 and 98 at their outputs a ONE state, which ensures that the relay contacts 111, 112 and the relay contacts 113, 114 even in the presence of a control signal on the conductor 148 are held in their open position. This prevents the control device the cutting device 50 is actuated. As with the embodiment of FIG. 5, the system is thus prevented from being erroneously actuated for as long an intermediate piece of the steel strip 9 below the photoelectric elements 17, 131, 130 and 16 glides past.

After an image of the deformed end piece on the photoelectric Element 17 has been passed, the detection of this part is triggered immediately. Under these circumstances, amplifiers 150 and 151 will give positive and zero outputs, respectively, whereby ZERO and ONE signals appear on lines 152 and 153, respectively.

When the rear part of the steel belt 9 on the photoelectric Arrangement 131 and 130 falls, the counter 135 gradually decreases its count in Compared to counter 135, resulting in an increase in the output of the di # erence former 138 leads. The comparator 139 is provided for the rear part of the steel strip 9, which at its output a signal depending on the output signal of the difference calculator 138 with respect to the reference signal. The signal from the comparator 139 is used for generating a cutting signal passed through NAND gate 98, such as this has already been described in connection with FIG. The elements for creation of the cutting signal are denoted by the same reference numerals as those of the corresponding elements of Figure 5.

The output signals of the samplers 134 and 135 can be obtained by the in FIG 7 are processed with the same reference symbols Designate identical components of FIG. 6. The output signals of the samplers 134 and 135 are fed to the own inputs of AND gates 170 and 171 while other inputs are connected to a timing terminal 172 at which timing pulses 166 # are placed, as they have already been described in connection with FIG are. Both AND gates 170 and 171 are with an OR gate 173 and accordingly connected to a counter 174.

similar to the embodiment of Figure 6, at the output terminal 175 of the scanner 134 shows a waveform 164 corresponding to the photoelectrical arrangement 130 formed, while the photoelectric arrangement 1 # 1 conditional Waveform occurs at output terminal 177 of sampler 135. The inversions of waveforms 164 and 165 also appear on the other output terminals 176 and 178 of samplers 134 and 135. In these circumstances the OR gate enables 173 that the timing pulses 166 are only passed if the waveform 164 has a positive potential or ONE value during the waveform i65 has a fULL potential or a NULL value. OR gate 173 results thus at the output time pulses, the number of which is the difference in widths between corresponds to both waveforms. The counter 174 counts the time pulses through the OR gate 173 pass through. In other respects, this embodiment is both in terms of construction and mode of operation of those shown in FIG Embodiment identical.

The embodiments of the invention described herein can be Pair of luminous parts regardless of the temperatures thereof with respect to compare the shape, these embodiments being particularly applicable to methods of Steel belt rollers are suitable. For example, with such a device one of both deformed end parts of a steel belt 9 to form a minimal accumulation of waste, increasing economy is increased while at the same time preventing uneven loading the end rollers come about, which results in damage to the same.

While the present invention is used in connection with the formation of Steel bands has been described, it should be understood that they also for temperature - and / or intensity measurement of lighting can be used is. Various modifications of the present invention are possible. For example the scanner can be built with field effect transistors which are not of the N-channel type are. The present invention can also be used for non-luminous objects as long as they are reflective. In the latter case, a too the comparative object is illuminated by means of a suitable light source, wherein the reflected light is compared in the manner already described will. Accordingly, the term "luminous" used is also intended to indicate emission of light due to reflection.

Claims (7)

Claims che Comparison system for luminous objects, consisting of two photoelectric Elements, especially for cutting off the front and rear ends of glowing steel strips during the rolling process, characterized in that on the photoelectric elements images (3, 4) of a part of the luminous object (9) are, resulting in an output signal that is at least the shape, the temperature or corresponds to the intensity of the illumination of the image, and that a comparison circle (7) is provided, which the output signals of the photoelectric elements (1 and 2) establishes, with those parts of the luminous object (9), its images (3, 4) are formed on the photoelectric elements (1, 2) with respect to compared the shape, temperature and / or intensity of the lighting are. 2) comparison system according to claim 1), characterized in that Ca ') two amplifiers (5, 6) are additionally provided and that the gain factor this amplifier (5, 6) is adjustable such that the comparison value of the Output signals of both amplifiers (5, 6) comparing comparison circle a measure for the relationship between the shape, temperature and intensity of the lighting. 3) comparison system according to claim 1 or 2, characterized in that that a voltage divider device is also provided, which the output signal at least a photoelectric element (I, 2) shares. 4) comparison system according to one of claims 1) to 3), characterized in that. that the photoelectric elements (1, 2) 130, 131) are solar cells 5) comparison system according to one of the preceding claims, characterized in that in the direction the following elements are provided for the movement of the luminous object (9): a) three photoelectric elements (14, 15, 16) arranged one behind the other, b) at least two sensors, of which def the first in the area of the third photoelectric element is arranged, c) end detectors, which the ends of the object to be measured determine, wherein d) a comparison circuit the output signals of the photoelectric Elements for the front end part of the object (9) and the output signals of the second and third photoelectric elements for the rear part of the object (9) compares. 6} comparison system according to claim 5), characterized in that the luminous objects (9) have essentially the same temperature and are compared with one another in terms of their shape. 7) comparison system according to claim 5), characterized in that at least four sensors are provided, which in the direction of movement of the object (9) are arranged one behind the other that two test circuits are also provided, one of them responding at the same time and the other not responding the sensors checks, and that a protective circuit is provided that the comparison system in the event of signals from one of these test circuits goes out of operation.