GB2205951A - Detecting the amount of wire on a reel - Google Patents
Detecting the amount of wire on a reel Download PDFInfo
- Publication number
- GB2205951A GB2205951A GB08714150A GB8714150A GB2205951A GB 2205951 A GB2205951 A GB 2205951A GB 08714150 A GB08714150 A GB 08714150A GB 8714150 A GB8714150 A GB 8714150A GB 2205951 A GB2205951 A GB 2205951A
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- Prior art keywords
- reel
- wire
- amount
- output
- coil
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
Abstract
Apparatus for detecting the amount of wire on a reel (10) e.g. wire for winding comprises an input coil (30) and an output coil (32) each surrounding the reel (10), a signal generator (36) that applies an alternating electrical signal to the input coil (30) and thereby induces in the output coil (32) an alternating electrical signal whose magnitude is affected by the amount of wire on the reel, and detector means (40) that rectifies the alternating signal induced in the output coil (32) to produce an output signal whose magnitude is representative of the amount of wire on the reel. The coils (30), (32) may be positioned axially of the reel (10) and spaced axially of one another. In the case of a plurality of reels each is provided with a respective coil assembly and detector means and switching means are provided to sequentially pass the output of the detector means to a display or wire constant decision circuit. <IMAGE>
Description
DETECTING THE AMOUNT OF WIRE ON A REEL
This invention relates to detecting the amount of wire on a reel.
It is known to manufacture electrical coils by means of automatic winding machines that withdraw wire from a reel and wind it on a bobbin or former. Often, such a machine will wind several like coils simultaneously, withdrawing wire from a corresponding plurality of reels. It is desirable, in such machines, not to commence a coil winding cycle if the reel or each reel does not hold a sufficient amount of wire to complete the winding operation. This is because, if a reel runs out (that is, becomes empty of wire) during a coil winding cycle, the coil being made has to be rejected: that is, there is a process loss. Furthermore, in the case of a machine that winds several coils simultaneously, the flailing loose wire end may damage adjacent coils being wound on the machine, thereby causing further rejects (process losses).
The problem of avoiding the running out of a reel, and therefore making the production process more efficient and less costly by minimising process losses, is not so simple to solve as first might appear te be the case. Firstly, the reels may not be positioned so that they can readily be seen by the machine operator. However, even if, for example by means of a mirror, the operator is able to see the reels readily, manual observation is not a reliable technique for estimating whether there is sufficient wire on each reel to complete a coil winding cycle. Particularly in the case of coils which require a lot of wire, it may not be possible to see that the wire is running out until it is too late.
There is therefore a need for a technique of detecting the amount of wire on a reel which does not rely on visual observation of the reel by an operator.
According to one aspect of the invention there is provided apparatus for detecting the amount of wire on a reel, the apparatus comprising:
an input coil and an output coil each positioned so as to surround the reel;
a signal generator operative to apply an alternating electrical signal to the input coil and thereby to induce in the output coil an alternating electrical signal whose magnitude is affected by the amount of wire on the reel; and
detector means operative to rectify the alternating signal induced in the output coil to produce an output signal whose magnitude is representative of the amount of wire on the reel.
The signal generator preferably comprises a square wave oscillator or generator and a differentiator for differentiating the square wave produced by the oscillator, whereby the alternating electrical signal applied to the input coil is a differentiated square wave. In a preferred embodiment described hereinbelow the frequency of the square wave is substantially equal to 350 Hz, though it is believed that higher frequencies may be employed.
The apparatus preferably includes wire amount decision means for generating a low wire supply signal if the magnitude of the output signal of the detector means is less than a level corresponding to a predetermined amount of wire remaining on the reel. The low wire supply signal can be used to provide an alarm (for example a visual alarm) and/or to inhibit operation of an associated coil winding machine until the reel is replaced.
The apparatus my include wire amount display means for displaying the magnitude of the output signal of the detector means and thereby displaying the amount of wire on the reel.
The apparatus may be used to detect the amount of wire on a plurality of reels. In this case, the input and output coils and the detector means may be replicated for each reel and switching means may be provided for switching the output signals from the respective detector means to the wire amount decision means and/or the wire amount display means in a predetermined sequence. Further, means may be provided for displaying, during said sequence, which of the reels is currently being monitored.
In the preferred embodiment described hereinbelow, the input and output coils are spaced axially of one another; and axially of the reel.
According to a second aspect of the invention there is provided a method of detecting the amount of wire on a reel, the method comprising:
positioning the reel with respect to an input coil and an output coil so that each coil surrounds the reel;
supplying an alternating electrical signal to the input coil so as to induce in the output coil an alternating electrical signal whose magnitude is affected by the amount of wire on the reel; and
rectifying the alternating signal induced in the output coil to produce an output signal whose magnitude is representative of the amount of wire on the reel.
The invention will now be further described, by of illustrative and non-limiting example, with reference to the accompanying drawings, in which:
Figure 1 is a cross-sectional view of a reel of wire positioned for use in an automatic coil winding machine;
Figure 2 is a side view, corresponding to Figure 1, showing input and output coils of an apparatus embodying the invention, the coils being positioned on a tubular surround for the reel;
Figure 3 is a block diagram of the apparatus embodying the invent ion;
Figure 4 is a circuit diagram of a square wave generator of the apparatus;
Figure 5 is a circuit diagram of a differentiator, a precision average detector, the pair of coils and a relay contact set of the apparatus;
Figure 6 is a circuit diagram of an amplifier and wire amount decision circuit of the apparatus;;
Figures 7A and 7B show waveforms observed across the input and output coils, respectively, for an empty (run out) reel;
Figures BA and 8B show waveforms corresponding to Figures 7A and 7B, respectively, for a partly used reel; and
Figures 9A and 9B show waveforms corresponding to Figures 7A and 7B, respectively, for a full (unused) reel.
Figure 1 shows an arrangement for housing a reel 10 of wire W which supplies wire to an automatic coil winding machine used for manufacturing flyback transformers, that is to say transformers for producing high voltages in colour television receivers. The arrangement comprises a tubular surround 12 which is formed of transparent plastics-material and is secured to a support surface 14.
The reel 10 rests on the support surface 14 within the surround 12. An inverted funnel-shaped member 16 rests on top of the surround 12. An end of the wire W on the reel 10 is led out through the top of the member 16, through a wire guide 18 secured to the top of the member 16, and is directed from there to the winding machine. In use, the winding machine applies tension te the wire to withdraw it from the reel 10.
The winding machine is operative to wind up to twelve coils simultaneously. Accordingly, tne arrangement shown in Figure 1 is replicated 12 times, the respective arrangements being positioned in two staggered rows of six on the support surface 14, which is arranged at the rear of the machine. In use, over a winding cycle that takes several minutes, the winding machine withdraws enough wire from each of the reels to form about 3000 turns of the wire around a slotted plastics bobbin.
The reel 10 comprises upper and lower flanges 20, 22 formed at opposite ends of, and integrally with, a slightly tapered spool 24.
The wire is round around the spool 24 between the flanges 20, 22. The diameter of the wire is 0.07 mm. The height of the reeled wire, that is to say the vertical dimension between the confronting faces of the flanges 20 and 22, is approximately equal to 100 mm. The maximum outer diameter of the reeled wire, at the base, before (as shown in
Figure 1) any substantial amount of wire has been drawn from the wheel, is approximately 95 mm. The wire 10 is of copper coated with a polyurethane varnish instant and conforms to a Japanese wire specification 1 UEW.
As explained aDove, it is desirable not to commence a coil winding cycle (an automatic operation for winding up to 12 coils simultaneously) if all of the reels do not hold a sufficient amount of wire to complete the winding operation. This is because, if a reel runs out (that is, becomes empty of wire), during a coil winding cycle, the coil being made has to be rejected: that is, there is a process loss. Furthermore, the flailing loose wire end may damage adjacent coils being wound in the machine, thereby causing further rejects (process losses).
An apparatus embodying the invention and described hereinbelow endeavours to solve this problem by detecting the amount of wire on each reel 10.
As shown in Figure 2, the apparatus includes an input coil 30 and an output coil 32 each wound around the exterior of the tubular surround 12 whereby, when a reel 10 is contained within the surround 12, each of the coils 30, 32 surrounds the reel 10. The reel 10 is shown in phantom in Figure 2 so that the positions of the coils 30, 32 with respect to the reel can be seen. The input coil 30 has 300 turns and the output coil 32 has 550 turns. The coils 30, 32 are spaced axially of one another, the confronting edges of the'coils being substantially adjacent one another, and axially of the surround 12 (and therefore of the reel 10). The lower edge of the coil 30 is positioned about 20 mm above the bottom edge of the surround 12. The axial heights of the coils 30 and 32 are about 30 mm and 60 mm, respectively.The external diameter of the surround 12, and therefore the internal diameters of the coils 30 and 32, is about 120 mm.
The ends of the coils 30, 32 are connected te a connection block 34 which may (as shown) be connected to the support surface 14 and/or may be connected to the surround 12. This enables the coils 30, 32 to be connected as described below. A capacitor (not shown) may be mounted to the connection block so as to be in series with a lead extending from the input coil 32 to the rest of the apparatus in order to reduce noise.
The apparatus, including the coils 30, 32, is shown in block diagram form in Figure 3. The apparatus includes a 350 Hz square wave generator or oscillator 36 which is connected via a differentiator 38 to the input coil 30 of one of the twelve reels 10 whereby, in use, a differentiated square wave is applied across the coil 30. One end of the input coil 30 is connected to one end of the output coil 32 and the connected ends are earthed (grounded). In a manner described more fully hereinbelow, the differentiated square wave applied across the input coil 30 leads to the induction in the output coil 32 of an alternating electrical signal whose magnitude is affected by the amount of wire on the reel 10.This signal is passed to a precision average detector 40 which rectifies the signal induced in the coil 32 to produce a dc output signal whose magnitude is representative of the amount of wire on the reel, the amplitude of the signal varying, for example, between about 2V for an empty reel and about 15V for a full reel. The dc output signal is connected via a relay contact set 42 to a line 44.
As shown partly in Figure 3, the combination of the differentiator 38, the coils 30, 32, the precision average detector 40 and the relay contact set 42 is replicated for each of the twelve reels 10. To this end, the square wave oscillator or generator 36 is connected by a line 46 to all twelve differentiators 38 and the line 44 is connected to all twelve relay contact sets 42.
The line 44 connected to the relay contact sets 42 is connected to an input of an amplifier 48. An output of the amplifier 48 is connected to a bar graph display driver 50, which drives a bar graph display 52, and to a wire amount decision circuit 52. The wire amount decision circuit 52 produces either a "LOW" output, on a line 54, which signifies that the amount of wire remaining on a reel is less than a predetermined value (lower limit) sufficient to wind another coil, or an "OK" output, on a line 56, which signifies that the amount of wire exceeds the predetermined value. The line 54 is connected to an input port of the winding machine to inhibit operation of the machine when the LOW output is generated.
The apparatus further comprises a square wave generator or oscillator 58 which operates at a frequency of 100 Hz and may comprise an astable multivibrator. An output of the generator 58 is connected to a divide-by-100 circuit 60 which supplies pulses at a frequency of 1 Hz on a line 62 to a reel selection control means 64. The reel selection control means 64 is responsive to the pulses applied thereto at the frequency of 1 Hz to monitor in turn the amounts of wire on the twelve respective reels 10. To this end, the reel selection control means (64) is connected to energise, in turn, respective ones of twelve relay coils 66 that operate the contact sets 42 so that a respective one of the output signals of the twelve precision average detectors 40 is supplied to the amplifier 48, via the line 44, at any one time.
The reel selection control means 64 is connected also to a reel number display means 68 (for example a conventional 7-segment display means) that will display the reel that currently is being monitored by displaying an appropriate one on the numbers 1 to 12.
The reel selection control means 64 is further connected to a reel status display means 70 that comprises 12 pairs of light omitting diodes (LEDs), each pair comprising a green LED and a red LED and each pair being associated with a respective one of the twelve reels 10.
The reel selection control means 64 enables energisation of each of the 12 pairs of LEDs of the reel status display means 70 in turn. The lines 54, 56 carrying the "LOW" and "OK" outputs of the wire amount decision circuit 52 are connected to the reel status display means 70 whereby, when energisation of a pair of the LEDs of the display means 70 is enabled, the green LED is illuminated in the event of the presence of the OK output and the red LED (which may be caused to flash) is energised in the event of the presence of the LOW signal.
The line 54 carrying the LOW output from the wire amount decision circuit 52 is connected also te the square wave generator 58 to inhibit its operation when the LOW output is present, thereby preventing the reel selection control means 64 from stepping to a further reel in the event that it is detected that the supply of wire on any one reel 10 is too low, that is lower than the predetermined value or lower limit.
Figure 4 shows the square wave generator or oscillator 36 in more detail. The generator 36 comprises a conventional operational amplifier circuit constituted by a differential amplifier 72, a variable resistor 74, a capacitor 76 and fixed resistors 78, 80 and 82. In a manner known per se, this produces a square wave output, the frequency of which can be tuned or adjusted by means of the variable resistor 74. The amplitude of the output of the operational amplifier circuit is clamped to 1.2 V peak to peak by means of diodes 84 connected as shown in a back-to-back configuration. The clamped output voltage is passed via another operational amplifier circuit, including a differential amplifier 86 and associated resistors, via an inductor 88 (330 microhenries) to the line 46 connected to the inputs of the twelve differentiators 38.
Figure 5 shows in more detail, for one of the reels 10, the combination of the differentiator 38, the coils 30, 32, the precision average detector 40 and the relay contact set 42.
The differentiator 38 is a conventional operational amplifier circuit comprising a differential amplifier 90 and an associated capacitor and resistors, the output of the circuit being applied across the input coil 30.
The precision average detector 40 comprises a capacitor 92 (0.22 microfarads), a variable resistor 94 and a fixed resistor 96 which connect the alternating electrical signal induced in the output coil 32, in the manner shown, to a precision rectifier 98 and an averager 100, each of which is of a conventional operational amplifier construction based upon a differential amplifier and associated passive components. In a manner Known per se, the precision rectifier 98 performs precision rectification of the signal induced in the output coil 32 and the averager 100 performs precision averaging of the rectified signal, whereby the averager 100 produces the abovementioned dc output signal, which is a precise average of the alternating signal induced across the coil 32.
Figure 6 shows the amplifier 48 and wire amount decision circuit 52 in more detail.
The amplifier 48 includes a differential amplifier 102. The dc output signal on the line 44, from whichever of the relay contact sets 42 is currently closed, is directed via a resistor 104 to the noninverting input of the differential amplifier 102. A set point dc signal from a potentiometer 106 is applied via a resistor 108 to the inverting input of the differential amplifier 102. The set point established by the potentiometer 106 is selected so as to correspond to the amount of wire remaining on the associated reel 10 being equal to the above-mentioned predetermined value (lower limit), that is to the amount of wire being insufficient to wind a further coil. If the dc output signal applied to the non-inverting input of the amplifier 102 is less than the set point signal applied to the inverting input, no signal is applied to the bar graph display driver 50.If, on the other hand, the dc output signal applied to the non-inverting input of the differential amplifier 102 is greater than the set point signal, a signal proportional to the difference is applied to the bar graph display driver 50. Accordingly, the bar graph display driver 50 drives the bar graph 52 to indicate the amount cf wire on the reel.
Bar graph display drivers and bar graph displays are, of course, well known, a bar graph serving to provide a linear display of the magnitude of a quantity. The bar graph may, for example, comprise 16
LEDs arranged in a line, the arrangement being such that all 16 are illuminated when the reel 10 is full and none cf them is illuminated when the reel 10 is below the set point corresponding to a low wire level. Note that, since the dc output signal from the precision average detector 40 may not vary linearly with the amount of wire on the reel 10, the number of illuminated LEDs on the bar graph 52 may not be linearly related to the amount of wire on the reel 10.
The output of the differential amplifier 102 of the amplifier 48 is passed also to an input of the wire amount decision circuit 52.
The circuit 52 comprises a differential amplifier 110 which receives the output of the differential amplifier 102 via a pair of back to back diodes 112 and a resistor 114. In similar manner to the differential amplifier 102 of the amplifier 48, the differential amplifier 110 of the decision circuit 52 compares the signal it receives at its noI1-inverting input with a set point signal applied to its inverting input from a potentiometer 116 via a resistor 114, the set point signal corresponding to the amount of wire remaining on the associated reel 10 being equal to the above-mentioned predetermined value (lower limit). The-back-to-back diodes 112 provide that only a signal having a magnitude of more than about 0.7v (in either direction) is passed to the non-inverting input of the amplifier 110.
An output signal from the differential amplifier 110 is passed via a diode 120 to a circuit comprising transistors 122, 1 1. The transistors 122, 124 are switched by the output of the differential amplifier 110, in such a manner that either the above-mentioned "OK" output (amount of wire remaining on the reel 10 greater than the predetermined lower limit) is produced on the line 56 or the "LOW" output (amount of wire remaining on the reel 10 less than the lower limit) is produced on the line 54. The differential amplifier 110 has a very high gain in order to switch the transistors 122, 124 very quickly in response to the dc signal arriving from the selected relay contact set 42 so that the OK or LOW output is developed by the decision circuit 52 well within the one second time interval allotted by the reel selection control means 64.
The apparatus functions, prior to the commencement of each winding cycle of the winding machine, in the following manner. The reel selection control means 64 causes energisation of one of the reel selection relay coils 66, whereby the corresponding one of the contact sets 42 thereof is closed, and causes the reel number display means 68 to display the number of the associated reel. The square wave from the generator 36 is differentiated by the associated differentiator 38 and applied to the associated input coil 30. The signal induced in the associated output coil 32 is averaged by the associated precision average detector 40 and passed via the closed contact set 42 to the amplifier 48 which causes the amount of wire on the associated reel 10 to be displayed on the bar graph 52 via the bar graph display driver 50.Provided that the amount of wire remaining on the reel 10 is greater than the predetermined lower limit, the wire amount decision circuit 52 produces the OK output on the line 56 whereby the green one of the associated pair of LEDs of the reel status display means 70 is illuminated.
One second later, the reel selection control means 64 steps to the next one of the relay contact sets 42 whereby the above procedure is repeated for the next reel. The stepping from reel to reel is repeated at one second intervals provided that it is determined that the amount of wire on each reel is above the predetermined lower limit. Suppose, however, that on stepping to a reel, the dc output signal from the associated precision average detector 40 indicates that the amount of wire on the associated reel 10 is below the lower limit. In this case, a zero display is produced on the bar graph 52.
Alsc, the wire amount decision circuit 52 produces the LOW output on the line 54. This causes three things to happen. Firstly, an inhibit signal is supplied to the winding machine input port so that the winding machine cannot be operated. Secondly, the red one of the associated pair of LEDs of the reel status display means 70 is illuminated to signal to the operator that the associated reel is low.
Thirdly, the operation of the square wave generator 58 is inhibited whereby the reel selection control means 64 does not step operation to the next reel until the current reel is replaced.
As indicated above, the apparatus relies for its operation on the surprising fact that the magnitude of the signal induced in the output coil 32 is affected by the amount of wire on the reel 10. The way in which the amount of wire on the reel 10 affects the magnitude of the signal induced in the output coil 32 will now be further described with reference to Figures 7A to 9B.
Figure 7A shows the waveform of the signal applied across the input coil 30 in the case cf an empty reel. It will immediately be appreciated that this a differentiated square wave. Figure 7B shows the corresponding signal induced across the output coil 32 in this case. It will be seen that this comprises a series of "spikes" (corresponding to the spikes of the input signal of Figure 7A) with a high frequency ripple effect known as "ringing" superimposed both on the spikes and on the parts of the signal between them. It is believed that the amount of ringing is proportional to the amount of wire on the reel. It will be appreciated that, when the signal shown in Figure 7B (that is, the fundamental component and the ringing component) is rectified and then averaged by the precision average detector- 40, it will not have a large magnitude.In fact, it has a magnitude of about 2 V dc.
Figure 8A shows the waveform of the signal applied across the input coil 30 in the case of a partly full reel 10. It will be observed that, in this case, a somewhat lower frequency ripple component is present on the input signal. Figure 8B shows that both the high frequency ripple and the low frequency ripple component appear on the output signal across the output coil 32. It will be evident from Figure 8B that, once the signal shown therein is full wave rectified and averaged in the precision average detector 40, it will have a somewhat higher de component. In fact, in this case the dc level is about 5 V.
Figure 9A shows the signal present across the input coil 30 in the case of a full reel. In will be observed that, in this case, both the high and low frequency ripple components appear in the input signal. Figure 9B shows the corresponding output signal, that is to say that induced across the output coil 32, and it will be seen that, in this case, both the high and low frequency ripple components again appear in the output signal. It will further be observed that, once the signal shown in Figure 9B has been rectified and averaged, it will have still greater dc level. The level in this case is in fact about 12 V.
The reason for the rather surprising effect that the amount of wire on the reel 10 affects the magnitude of the signal induced across the winding 32 is not clearly understood. It is at first tempting to consider the reel 10 as acting like the core of a transformer.
However, this analogy is not helpful, bearing in mind that the reel 10 does not contain magnetically susceptible material whereby varying the amount of wire on the reel 10 does not constitute an alteration in the reluctance of a magnetic circuit. It is possible that the coupling effect is predominently or even wholly capacitive rather than magnetic. It appears that the secondary coil 32 may act somewhat like a receiving aerial (antenna) for the signal applied to the input coil 30, the quality of reception of the signal in the coil 32 being affected by the amount of wire on the reel 10. The above-mentioned ringing phenomenon appears to play an important part, possibly a crucial part, in the action: in fact, it is believed that the magnitude of the ringing component is proportional to the amount of wire on the reel. Certainly, it was found that the use of a differentiated square wave, which is presumed to engender the ringing by virtue of the high frequency component thereof caused by differentiation, produces by far the best results. Other waveforms that can cause ringing may be satisfactory. Probably, the use of a smoothly alternating wave form such as a sinusoid would not produce acceptable results.
Further, some care was necessary to choose an appropriate frequency. As indicated above, tuning the signal applied to the input coil 30 to a frequency close to or equal to 350 Hz was found necessary for correct operation in the present case. However, it may well be that, for reels 10 of different dimensions and/or numbers of turns, other frequencies, especially higher ones, would be appropriate.
Claims (24)
1. Apparatus for detecting the amount of wire on a reel, the apparatus comprising:
an input coil and an output coil each positioned so as to surround the reel;
a signal generator operative to apply an alternating electrical signal to the input coil and thereby to induce in the output coil an alternating electrical signal whose magnitude is affected by the amount of wire on the reel; and
detector means operative to rectify the alternating signal induced in the output coil to produce an output signal whose magnitude is representative of the amount of wire on the reel.
2. Apparatus according to claim 1, wherein the signal generator comprises a square wave oscillator or generator and a differentiator for differentiating the square wave produced by the oscillator, whereby the alternating electrical signal applied to the input coil is a differentiated square wave.
3. Apparatus according to claim 2, wherein the frequency of the square wave is substantially equal to 350 Hz.
4. Apparatus according to claim 2, wherein the frequency of the square wave is greater than 350 Hz.
5. Apparatus according to any one of the preceding claims, wherein the input and output coils are spaced axially of one another.
6. Apparatus according to claim 5, wherein the input and output coils are positioned axially of the reel.
7. Apparatus according to any one of the preceding claims, which includes wire amount decision means for generating a low wire supply signal if the magnitude of the output signal of the detector means is less than a level corresponding to a predetermined amount of wire remaining on the reel.
8. Apparatus according to any one of the preceding claims, which includes wire amount display means for displaying the magnitude of the output signal of the detector means and thereby displaying the amount of wire on the reel.
9. Apparatus according to claim 7, for detecting the amount of wire on a plurality of reels, in which a respective input and output coil and a respective detector means are provided for each reel and switching means is provided for switching the output signals from the respective detector means to the wire amount decision means in a predetermined sequence.
10. Apparatus according to claim 8, for detecting the amount of wire on a plurality of reels, in which a respective input and output coil and a respective detector means are provided for each reel and switching means is provided for switching the output signals from the respective detector means to the wire amount display means in a predetermined sequence.
11. Apparatus according to claim 9 or claim 10, which includes means for displaying, during said predetermined sequence, which of the reels is currently being monitored.
12. Apparatus for detecting the amount of wire on a reel, the apparatus being substantially as herein described with reference to the accompanying drawings.
13. A method of detecting the amount of wire on a reel, the method comprising:
positioning the reel with respect to an input coil and an output coil so that each coil surrounds the reel;
supplying an alternating electrical signal to the input coil so as to induce in the output coil an alternating electrical signal whose magnitude is affected by the amount of wire on the reel; and
rectifying the alternating signal induced in the output coil to produce an output signal whose magnitude is representative of the amount of wire on the reel.
14. A method according to claim 13, wherein the alternating electrical signal applied to the input coil is a differentiated square wave.
15. A method according to claim 14, wherein the frequency of the square wave is substantially equal to 350 Hz.
16. A method according to claim 14, wherein the frequency of the square wave is greater than 350 Hz.
17. A method according to any one of claims 13 to 16, wherein the input and output coils are spaced axially of one another.
18. A method according to claim 17, wherein the input and output coils are positioned axially of the reel.
19. A method according to any one of claims 13 to 18, wherein a low wire supply signal is generated if the magnitude of the output signal is less than a level corresponding to a predetermined amount of wire remaining on the reel.
20. A method according to any one of claims 13 to 19, which includes displaying the magnitude of the output signal and thereby displaying the amount of wire on the reel.
21. A method according to claim 19, for detecting the amount of wire on a plurality of reels, wherein a respective input and output coil is provided for each reel, said rectifying step is performed for each reel, and the output signals produced by the respective rectifying steps are supplied to a common wire amount decision means, for generating said low wave supply signal, in a predetermined sequence.
22. A method according to claim 20, for detecting the amount of wire on a plurality of reels, wherein a respective input and output coil is provided for each reel, said rectifying step is performed for each reel, and the output signals produced by the respective rectifying steps are supplied to a common display means for displaying the amounts of wire on the respective reels in a predetermined sequence.
23. A method according to claim 21 or claim 22, including displaying, during said predetermined sequence, which of the reels is currently being monitored.
24. A method of detecting the amount of wire on a reel, the method being substantially as herein described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08714150A GB2205951A (en) | 1987-06-17 | 1987-06-17 | Detecting the amount of wire on a reel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08714150A GB2205951A (en) | 1987-06-17 | 1987-06-17 | Detecting the amount of wire on a reel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8714150D0 GB8714150D0 (en) | 1987-07-22 |
| GB2205951A true GB2205951A (en) | 1988-12-21 |
Family
ID=10619062
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08714150A Withdrawn GB2205951A (en) | 1987-06-17 | 1987-06-17 | Detecting the amount of wire on a reel |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2205951A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2234496A (en) * | 1989-07-05 | 1991-02-06 | Gd Spa | Web monitoring |
| GB2238876A (en) * | 1989-11-20 | 1991-06-12 | Motorola Inc | Solder paste dispensing sensor |
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| GB2097929A (en) * | 1981-04-01 | 1982-11-10 | Newtek Electronic Products Ltd | Apparatus for sensing the level of coins |
| GB2107875A (en) * | 1981-09-15 | 1983-05-05 | Cardrox Systems Limited | Inductive switches |
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1987
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1022373A (en) * | 1963-10-24 | 1966-03-09 | Head Wrightson & Co Ltd | Improvements relating to control of flow of particulate solid materials through pipes |
| GB1426211A (en) * | 1972-08-31 | 1976-02-25 | Siemens Ag | Determining the degree of insertion of nuclear reactor control members |
| GB1418476A (en) * | 1972-10-17 | 1975-12-24 | Frankel Aluminium Ltd J | Detection of ferromagnetic materials |
| US4083002A (en) * | 1976-02-17 | 1978-04-04 | Allport John J | Method and apparatus for measuring cross sectional area and weight per unit length of elongated, conductive material by magnetic field displacement |
| GB2097929A (en) * | 1981-04-01 | 1982-11-10 | Newtek Electronic Products Ltd | Apparatus for sensing the level of coins |
| GB2107875A (en) * | 1981-09-15 | 1983-05-05 | Cardrox Systems Limited | Inductive switches |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2234496A (en) * | 1989-07-05 | 1991-02-06 | Gd Spa | Web monitoring |
| US5177446A (en) * | 1989-07-05 | 1993-01-05 | G. D. Societa Per Azioni | Device for monitoring the depletion of material uncoiling from rolls, applicable in particular to wrapping machines |
| GB2234496B (en) * | 1989-07-05 | 1994-03-23 | Gd Spa | A device for monitoring the depletion of material uncoiling from rolls,applicable in particular to wrapping machines |
| GB2238876A (en) * | 1989-11-20 | 1991-06-12 | Motorola Inc | Solder paste dispensing sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8714150D0 (en) | 1987-07-22 |
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| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |