CA1135384A - Control of thread processing machinery - Google Patents
Control of thread processing machineryInfo
- Publication number
- CA1135384A CA1135384A CA000341767A CA341767A CA1135384A CA 1135384 A CA1135384 A CA 1135384A CA 000341767 A CA000341767 A CA 000341767A CA 341767 A CA341767 A CA 341767A CA 1135384 A CA1135384 A CA 1135384A
- Authority
- CA
- Canada
- Prior art keywords
- monitoring
- processing
- transducers
- thread
- tension
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
- D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
- D02G1/00—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics
- D02G1/02—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist
- D02G1/0206—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist by false-twisting
- D02G1/0266—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist by false-twisting false-twisting machines
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Textile Engineering (AREA)
- Spinning Or Twisting Of Yarns (AREA)
- Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
Abstract
14.
ABSTRACT
Control of Thread Processing Machinery In a thread processing, e.g. a false twist crimping, machine, thread tension is monitored by microprocessors scanning tension transducers in groups, so that fast sampling, e.g. 80 samples/second, can detect fast tension transients that could otherwise lead to noticeable fabric faults. A typical 216 threadline machine has nine microprocessors each scanning twenty four threadlines and reporting to and receiving instructions from a central display and control unit.
ABSTRACT
Control of Thread Processing Machinery In a thread processing, e.g. a false twist crimping, machine, thread tension is monitored by microprocessors scanning tension transducers in groups, so that fast sampling, e.g. 80 samples/second, can detect fast tension transients that could otherwise lead to noticeable fabric faults. A typical 216 threadline machine has nine microprocessors each scanning twenty four threadlines and reporting to and receiving instructions from a central display and control unit.
Description
1353~ ' Control of Thread Processing Machinery This invention relates to monitoring systems for yarn or thread processing machines of the kind in which a plurality of threads is processed in a plurality of similar processing stations, each processing station comprising a transducer giving an electrical output representative of the value of a processing parameter in that processing station for monitoring or control purposes.
Such thread processing machines may comprise false twist yarn bulking machines. These have a plurality of similar yarn processing stations - up to 200 or so - arranged side by side along the machine. At each processing station yarn is withdrawn from a supply package and fed through a heater and a false twister -either of the pin or of the friction type - so as to impart a bulk and crimp thereto. On some machines the thus treated yarn, which is capable of undergoing substantial contractions, may be subjected, under controlled contraction, to a further heating step before being wound up, to produce what is known as set yarn.
For quite a few years now such machines have had close control and monitoring of their heater temperatures - there being heaters to heat the false twisted yarn, and post-treating heaters to set the yarn under controlled contraction. To avoid a multiplicity of dials or ocher indicating devices, thermometers (usually resistance thermometers) in the heaters have been"scanned" - that is to say, inspected serially by electric switching means, the temperatures (or, rather, temperature errors) being displayed consecutively on a common indicator. Such a system has also comprised alarm means adapted to warn of "off limits" temperature at any heater so that an operator can check the position and attend to any fault. By "off limits"
is meant either above or below a predetermined .,~ ;.,,~
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temperature range. Using such systems, machines have held their heater temperatures to within a degree of so Celsius at temperatures in the region of 200C.
Also on such machines, thread detectors have been used to indicate ends down. Such thread detectors have usually been applied individually at each spindle position, an indicator light of the thread detector illuminated at a particular position telling of an end down, a stop motion also being actuated to stop thread feeding at such position to avoid, among other things, laps on feed rollers.
More recently, attention has been paid to the monitoring of thread quality. This has become of some importance partly as a result of the advent of draw texturing (in which undrawn or, more usually, partially oriented yarn is used as the feed stock and drawing takes place on the false twisting machine) and partly as a result of demands for higher quality yarn - or ~erhaps as a result of a desire to produce more top-quality yarn to maximise the return on the high capital investment in modern processing machinery. Quality variations arise from a variety of factors - some as a result of variations in the frictional properties of the yarn, others as a result of some irregularity in the spinning process, while yet others arise within the false twisting process itself.
Up to a point, such quality variation can be tolerated.
If, however, the average quality of a yarn is different from that of other yarns being processed at the same time on the same machine, or if it varies over a period of time, and the difference or variation exceeds a certain value, the dye uptake and appearance of the resulting yarn or fabrics made from it will be uneven.
With this in mind, attempts have been made to monitor or control yarn quality in yarn processing machinery and 1~3S38~
some of these attempts have involved scanning tension-measuring transducers in similar fashion to the longer-established heater temperature scanning systems. These tension-monitoring systems have in large measure been modelled on the known temperature scanning systems.
W~ have found, however, that there are essential differences between temperature and tension variations that make these prior art tension-monitoring systems relatlvely ineffective.
The present invention provides an improved monitoring system particularly adapted to monitoring parameters that vary like thread tension.
The invention comprises a monitoring system in or for a thread processing machine of the kind inwhich a plurality of threads is processed ina plurality of similar processing stations, each processing station having a transducer giving an electrical output representative of the value of a processing parameter in that processing station, characterised in that said monitoring system comprises monitoring units (numbering less than the number of said processing stations),each monitoring unit being connected to a group of said transducers to receive, process and store information from the electrical outputs thereof serially and adapted to scan said group of transducers repeatedly, said monitoring units being connected to a common display and control unit for said system.
Thread processing machinery such as false twist crimping machinery is customarily assembled as a plurality of "bays" each bay having a plurality of processing stations. The bays are joined together-and completed by "end legs" housing drive and control equipment.
Each bay may then comprise at least one of said monitoring units.
A monitoring unit can then scan its group of ` ` ' ~ ~;
, ;"`~ ~ '~` `' , . .
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transducers in a time corresponding to a small thread throughput.
When monitoring thread tension, especially in today's high speed texturising machines, this is important in that thread tension is subject to short-lived variations -possibly caused, for example, by short-term lack or excess of lubricant on the thread. By comparison, heater temperature variation is a relatively leisurely affair, and temperature monitoring-based systems cannot cope with these short-term variations. However, even a variation of 10% in the tension level lasting only afraction of a second can give rise to a visible fault in a fabric knitted from the yarn. At 1,000 m/minute throughput, a tension surge lasting 0.1 sec. can spoil 1.67 metres of thread.
Such lengths of faulty yarn can easily give rise to notice-able fabric faults.
A monitoring unit may trigger an alarm when the monitored processing parameter is off limits; and the system may have a facility for adjusting the processing parameter limits (for example, for processing different kinds or weights of yarn). Such limit adjusting facility may be common to all monitoring units - and may be controlled from thecommon display and control unit located in an end leg, for instance, of a texturising machine.
A monitoring unit may comprise a microprocessor programmed to pass selected information derived from the transducers to a common data processing unit comprised in said display and control unit. The monitoring units and the common data processing unit may be connected by light guides - this is particularly advantageous in a noisy electrical environment to avoid interference and spurious signals originating from other nearby electrical equipment.
More than one parameter may be monitored, and the system can also be adapted to monitor "whole machine"
parameters as well as other individual threadline parameters such as heater temperatures.
.
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Examples of such "whole machine" parameters include overfeeds, main shaft speed, traverse speed (on the yarn wind-up mechanism, for instance), gearbox temperatures and so on. The system can be programmed to monitor S different parameters at different time intervals -gearbox temperature, for example, need not be sampled anything like so often as thread tension.
A monitoring system in a thread processing machine according to the invention will now be described with reference to the accompanying drawings, in which:-Figure 1 is a schematic diagram of a false twist texturising machine for producing set yarn.
Figure 2 is a block diagram of a monitoring system suitable for the machine illustrated in Figure 1, Figure 3 is a block diagram of a monitoring unit of the system illustrated in Figure 2, Figure 4 is a timing cycle for a microprocessor of the monitoring unit illustrated in Figure 3, and Figure 5 is a timing cycle for a data link - between the monitoring units and the common display and control unit of the system illustrated in Figure 2.
The false twist texturising machine illustrated in Figure 1 comprises a plurality of processing stations each having a support 11 for a supply of unprocessed partially o-iented yarn 12 on a package 13, the support 11 being part of a free-standing creel C. The yarn 12 is withdrawn from the package 13 by feed rollers 14 on a shaft 15. The yarn 12 is pulled ~ ough a heating and fa~e twisting ,~ . .
' ~13S389~
6.
zone 16 by further feed rollers 17. Each such zone 16 has a curved plate contact heater 18 processing two yarns 12 in separate grooves thereof, and two Positorq (Registered Trade Mark) friction false twist devices 20, 5 one for each yarn. The feed rollers 17 run faster than the rollers 14 by a factor o about 1.6 to 1 in order to draw the yarn simultaneously with the false twisting thereof.
At the feed rollers 17, the yarn is a potentially 10 contractible false twist crimped yarn which, however, has not yet been allowed to contract because of the relatively high tension to which it is subjected. However, the yarn is fed by the feed rollers 17 into a relaxation zone 30 including a second heater 19, the yarn being withdrawn 15 from said zone 30 by further feed rollers 21 which run some 15% more slowly than the feed rollers 17 thus allowing the yarn to contract. Because of its heat treatment in this relaxed condition, the yarn is relieved in large measure of its tendency to contract in length by 20 the development of crimp. The yarn delivered by the feed rollers 21 i5 wound up in wind up means 22, which run usually a little faster than the rollers 21, in order to build a stable yarn packa~e.
The yarns are traversed from end to end of the wind 25 up packages by traverse guides 23 on a traverse rod 24 reciprocated by a cam mechanism 25. The cam mechanism 25 has a disturber or "pattern breaker" mechanism 26 to eliminate the formation of "ribbons" of yarn during the wind.
The false twist devices 20 are driven by a belt 27 trained over pulleys 28, 29 at the ends of the machine, one pulley, 28, being connected to main drive motor 31 which also drives all the feed rollers and the wind up through suitable ~earing.
The machine is constructed of two "end legs" 32, 33 .
. .
.
~3S38~
housing the motor 31, pulleys 28, 29, gearing and main bearings for the shafts carrying the feed rollers and the wind-up rollers and other equipment, and a plurality of 'bays' 34 of processing stations. For example, a 5 machine having two hundred and sixteen processing stations can have nine bays each having twenty four stations, arranged twelve on each side of the machine. As mentioned, each of the heaters 18 serves two yarns so each bay has twelve such heaters, six on each side. The secondary 10 heater 19 is a tube heater, the tube being mounted along with twenty three others in a heating chamber 35 serving an entire bay 34 and having a single temperature sensor 36 connected to a temperature controller 37 of which there are nine, one for each heating chamber 35, in a 15 heater control arrangement 38 in end leg 32. The heaters 18, in the same way, have temperature sensors 39 connected to controllers 40 in the control arrangement 38.
Tension is sensed in such a machine on the output side of the Positorq (Registered Trade Mark) device, and 20 a tension transducer 41, comprising essentially a strain gauge, is situated between the Positorq device 20 and the feed rollers 21 at each processing station. Thus there is a total of two hundred and si~teen transducers 41, twenty four to each bay 34.
Figures 2 and 3 illustrate a monitoring system for the tension transducers 41 in such a machine. The system comprises nine monitoring units Ml, M2, .... M9 each one connected to the twenty four transducers 41 in one of the nine bays of the machine to receive, process and store 30 information from the electrical outputs thereof serially, and each adapted to scan its group of transducers 41 repeatedly, the monitoring units Ml, M2, .... M9 being connected to a common display and control unit 42 for the system. The display and control unit is housed in end 35 leg 32 (Figure 1). It includes a video display unit VDU, - - \
113S38~
which is also adapted as will be explained hereinafter to display information other than tension information.
Figure 3 illustrates one of the monitoring units Ml, M2, .... M9. It comprises a crystal-cont~olled, ~icro-processor 43 (for which an Intel 8085 is a~ SU~lt ~ e choice) together with an electrically programmed read only memory 44 and a random access memory 45 - the 8755 EPRO~ (2 kbyte capacity~ and the 8155 RAM 256 eight bit words) being complementary to the 8085 chip. The 8155 RAM and the 8755 EPROM provide ports for external data transfer.
The system has control, data and address busses 48, 49, 50 respectively.
The tension inputs from the twenty four tension transducers in the bay are multiplexed in a twenty five way multiplexer 51 (the twenty fifth input being from a dummy tension transducer 59 used as a check on the level of excitation of the active transducers). The transducers are driven by drive circuitry 60. The multiplexed tension inputs are converted to digital signals suitable for the microprocessor by an analogue to digital convertor 52.
The muliplexer 51 is controlled via a six bit word from RAM 46, which i5 sufficient to address the twenty five tension transducers.
Yarn tension in high speed false twist crimping machines may well contain frequency components up to 30 Hz.
A suitable sampling rate is eighty per second, giving a total input of 80 x 25 = 2,000 tension readings per second, or one rading every 500~ s. This can be achieved using a timing cycle as illustrated in Figure 4 as follows:-Al - data held on integrator - -5~ s A2 - multiplexer 51 stepped to next position - 20~ s A3 - data converted from analogue to digital - 30~ s ' ~ ' `
113S3~g 9~
A4 - integrator switched to sample next channel - 5~ s A5 - arithmetic to form average and test for limits - 40~ s A6 - integrator observes tension signal for 400~ s without attention from the micro-processor which can carry out other duties such as broken thread alarms and controlling the data link (see below) to the central processor - 400~s This is repeated for each of the twenty five tension channels Cl, C2, .... C25, and each complete scan, - 15 therefore takes 12.5 ms. The tension signal will be analysed in the microprocessor to determine its average and checked against limits for average tension.
Instantaneous level will also be checked against limits, either one of these tests giving rise, if required, to an alarm condition. Averaging takes, obviously, a few seconds. 256 samples of eight bit data add up to sixteen bits or two eight bit words. Thus, if 256 samples are chosen for averaging, the twenty four tension averages from a bay can be reported to the central processor in 2 x 24 = 48 words. 256 samples takes 3.2 seconds which is adequate for establishing an average tension.
The nine bays are multiplexed on the data link to the . .
central processor 42 which is via a data link controller ~DLC) 54. This converts data to serial form for transmission down a single transmission line and performs parity checks.
Broken thread detection is also monitored in the microprocessor, inputs from twenty four broken thread - :
., ~. :
. :
131 3S38~
10 .
detectors being connected through photo couplers 53 to inputs on the EPROM 44 and RAM 45.
Figure 5 shows how only about half the data link timing cycle is used to report bay data, leaving the other half for transmission of other data along the machine, for example, heater temperatures.
So the system allows very fast scanning of tension -eighty samples per second on each threadline - which is required to catch transient off-limits tensions, while still having capacity to include other machine variables for which additional memory can be provided if required.
This is in contradistinction to prior art tension monitoring systems that scan all two hundred or so threadlines serially, spending several seconds sampling each threadline, so that even quite long period off-limits tensions will pass unnoticed.
Connection of the DLC 54 to the control and display unit 42 is desirably by a light guide coupling 55 with input and output light guides 56, 57. This avoids interference from yarn cutters, temperature controllers and other neighbouring electrical equipment on the machine.
The control and display unit 42 illustrated in Figure
Such thread processing machines may comprise false twist yarn bulking machines. These have a plurality of similar yarn processing stations - up to 200 or so - arranged side by side along the machine. At each processing station yarn is withdrawn from a supply package and fed through a heater and a false twister -either of the pin or of the friction type - so as to impart a bulk and crimp thereto. On some machines the thus treated yarn, which is capable of undergoing substantial contractions, may be subjected, under controlled contraction, to a further heating step before being wound up, to produce what is known as set yarn.
For quite a few years now such machines have had close control and monitoring of their heater temperatures - there being heaters to heat the false twisted yarn, and post-treating heaters to set the yarn under controlled contraction. To avoid a multiplicity of dials or ocher indicating devices, thermometers (usually resistance thermometers) in the heaters have been"scanned" - that is to say, inspected serially by electric switching means, the temperatures (or, rather, temperature errors) being displayed consecutively on a common indicator. Such a system has also comprised alarm means adapted to warn of "off limits" temperature at any heater so that an operator can check the position and attend to any fault. By "off limits"
is meant either above or below a predetermined .,~ ;.,,~
~r;~
, '':
: ~ ".
1~353~3~
temperature range. Using such systems, machines have held their heater temperatures to within a degree of so Celsius at temperatures in the region of 200C.
Also on such machines, thread detectors have been used to indicate ends down. Such thread detectors have usually been applied individually at each spindle position, an indicator light of the thread detector illuminated at a particular position telling of an end down, a stop motion also being actuated to stop thread feeding at such position to avoid, among other things, laps on feed rollers.
More recently, attention has been paid to the monitoring of thread quality. This has become of some importance partly as a result of the advent of draw texturing (in which undrawn or, more usually, partially oriented yarn is used as the feed stock and drawing takes place on the false twisting machine) and partly as a result of demands for higher quality yarn - or ~erhaps as a result of a desire to produce more top-quality yarn to maximise the return on the high capital investment in modern processing machinery. Quality variations arise from a variety of factors - some as a result of variations in the frictional properties of the yarn, others as a result of some irregularity in the spinning process, while yet others arise within the false twisting process itself.
Up to a point, such quality variation can be tolerated.
If, however, the average quality of a yarn is different from that of other yarns being processed at the same time on the same machine, or if it varies over a period of time, and the difference or variation exceeds a certain value, the dye uptake and appearance of the resulting yarn or fabrics made from it will be uneven.
With this in mind, attempts have been made to monitor or control yarn quality in yarn processing machinery and 1~3S38~
some of these attempts have involved scanning tension-measuring transducers in similar fashion to the longer-established heater temperature scanning systems. These tension-monitoring systems have in large measure been modelled on the known temperature scanning systems.
W~ have found, however, that there are essential differences between temperature and tension variations that make these prior art tension-monitoring systems relatlvely ineffective.
The present invention provides an improved monitoring system particularly adapted to monitoring parameters that vary like thread tension.
The invention comprises a monitoring system in or for a thread processing machine of the kind inwhich a plurality of threads is processed ina plurality of similar processing stations, each processing station having a transducer giving an electrical output representative of the value of a processing parameter in that processing station, characterised in that said monitoring system comprises monitoring units (numbering less than the number of said processing stations),each monitoring unit being connected to a group of said transducers to receive, process and store information from the electrical outputs thereof serially and adapted to scan said group of transducers repeatedly, said monitoring units being connected to a common display and control unit for said system.
Thread processing machinery such as false twist crimping machinery is customarily assembled as a plurality of "bays" each bay having a plurality of processing stations. The bays are joined together-and completed by "end legs" housing drive and control equipment.
Each bay may then comprise at least one of said monitoring units.
A monitoring unit can then scan its group of ` ` ' ~ ~;
, ;"`~ ~ '~` `' , . .
113S;~
4.
transducers in a time corresponding to a small thread throughput.
When monitoring thread tension, especially in today's high speed texturising machines, this is important in that thread tension is subject to short-lived variations -possibly caused, for example, by short-term lack or excess of lubricant on the thread. By comparison, heater temperature variation is a relatively leisurely affair, and temperature monitoring-based systems cannot cope with these short-term variations. However, even a variation of 10% in the tension level lasting only afraction of a second can give rise to a visible fault in a fabric knitted from the yarn. At 1,000 m/minute throughput, a tension surge lasting 0.1 sec. can spoil 1.67 metres of thread.
Such lengths of faulty yarn can easily give rise to notice-able fabric faults.
A monitoring unit may trigger an alarm when the monitored processing parameter is off limits; and the system may have a facility for adjusting the processing parameter limits (for example, for processing different kinds or weights of yarn). Such limit adjusting facility may be common to all monitoring units - and may be controlled from thecommon display and control unit located in an end leg, for instance, of a texturising machine.
A monitoring unit may comprise a microprocessor programmed to pass selected information derived from the transducers to a common data processing unit comprised in said display and control unit. The monitoring units and the common data processing unit may be connected by light guides - this is particularly advantageous in a noisy electrical environment to avoid interference and spurious signals originating from other nearby electrical equipment.
More than one parameter may be monitored, and the system can also be adapted to monitor "whole machine"
parameters as well as other individual threadline parameters such as heater temperatures.
.
~13S;~
Examples of such "whole machine" parameters include overfeeds, main shaft speed, traverse speed (on the yarn wind-up mechanism, for instance), gearbox temperatures and so on. The system can be programmed to monitor S different parameters at different time intervals -gearbox temperature, for example, need not be sampled anything like so often as thread tension.
A monitoring system in a thread processing machine according to the invention will now be described with reference to the accompanying drawings, in which:-Figure 1 is a schematic diagram of a false twist texturising machine for producing set yarn.
Figure 2 is a block diagram of a monitoring system suitable for the machine illustrated in Figure 1, Figure 3 is a block diagram of a monitoring unit of the system illustrated in Figure 2, Figure 4 is a timing cycle for a microprocessor of the monitoring unit illustrated in Figure 3, and Figure 5 is a timing cycle for a data link - between the monitoring units and the common display and control unit of the system illustrated in Figure 2.
The false twist texturising machine illustrated in Figure 1 comprises a plurality of processing stations each having a support 11 for a supply of unprocessed partially o-iented yarn 12 on a package 13, the support 11 being part of a free-standing creel C. The yarn 12 is withdrawn from the package 13 by feed rollers 14 on a shaft 15. The yarn 12 is pulled ~ ough a heating and fa~e twisting ,~ . .
' ~13S389~
6.
zone 16 by further feed rollers 17. Each such zone 16 has a curved plate contact heater 18 processing two yarns 12 in separate grooves thereof, and two Positorq (Registered Trade Mark) friction false twist devices 20, 5 one for each yarn. The feed rollers 17 run faster than the rollers 14 by a factor o about 1.6 to 1 in order to draw the yarn simultaneously with the false twisting thereof.
At the feed rollers 17, the yarn is a potentially 10 contractible false twist crimped yarn which, however, has not yet been allowed to contract because of the relatively high tension to which it is subjected. However, the yarn is fed by the feed rollers 17 into a relaxation zone 30 including a second heater 19, the yarn being withdrawn 15 from said zone 30 by further feed rollers 21 which run some 15% more slowly than the feed rollers 17 thus allowing the yarn to contract. Because of its heat treatment in this relaxed condition, the yarn is relieved in large measure of its tendency to contract in length by 20 the development of crimp. The yarn delivered by the feed rollers 21 i5 wound up in wind up means 22, which run usually a little faster than the rollers 21, in order to build a stable yarn packa~e.
The yarns are traversed from end to end of the wind 25 up packages by traverse guides 23 on a traverse rod 24 reciprocated by a cam mechanism 25. The cam mechanism 25 has a disturber or "pattern breaker" mechanism 26 to eliminate the formation of "ribbons" of yarn during the wind.
The false twist devices 20 are driven by a belt 27 trained over pulleys 28, 29 at the ends of the machine, one pulley, 28, being connected to main drive motor 31 which also drives all the feed rollers and the wind up through suitable ~earing.
The machine is constructed of two "end legs" 32, 33 .
. .
.
~3S38~
housing the motor 31, pulleys 28, 29, gearing and main bearings for the shafts carrying the feed rollers and the wind-up rollers and other equipment, and a plurality of 'bays' 34 of processing stations. For example, a 5 machine having two hundred and sixteen processing stations can have nine bays each having twenty four stations, arranged twelve on each side of the machine. As mentioned, each of the heaters 18 serves two yarns so each bay has twelve such heaters, six on each side. The secondary 10 heater 19 is a tube heater, the tube being mounted along with twenty three others in a heating chamber 35 serving an entire bay 34 and having a single temperature sensor 36 connected to a temperature controller 37 of which there are nine, one for each heating chamber 35, in a 15 heater control arrangement 38 in end leg 32. The heaters 18, in the same way, have temperature sensors 39 connected to controllers 40 in the control arrangement 38.
Tension is sensed in such a machine on the output side of the Positorq (Registered Trade Mark) device, and 20 a tension transducer 41, comprising essentially a strain gauge, is situated between the Positorq device 20 and the feed rollers 21 at each processing station. Thus there is a total of two hundred and si~teen transducers 41, twenty four to each bay 34.
Figures 2 and 3 illustrate a monitoring system for the tension transducers 41 in such a machine. The system comprises nine monitoring units Ml, M2, .... M9 each one connected to the twenty four transducers 41 in one of the nine bays of the machine to receive, process and store 30 information from the electrical outputs thereof serially, and each adapted to scan its group of transducers 41 repeatedly, the monitoring units Ml, M2, .... M9 being connected to a common display and control unit 42 for the system. The display and control unit is housed in end 35 leg 32 (Figure 1). It includes a video display unit VDU, - - \
113S38~
which is also adapted as will be explained hereinafter to display information other than tension information.
Figure 3 illustrates one of the monitoring units Ml, M2, .... M9. It comprises a crystal-cont~olled, ~icro-processor 43 (for which an Intel 8085 is a~ SU~lt ~ e choice) together with an electrically programmed read only memory 44 and a random access memory 45 - the 8755 EPRO~ (2 kbyte capacity~ and the 8155 RAM 256 eight bit words) being complementary to the 8085 chip. The 8155 RAM and the 8755 EPROM provide ports for external data transfer.
The system has control, data and address busses 48, 49, 50 respectively.
The tension inputs from the twenty four tension transducers in the bay are multiplexed in a twenty five way multiplexer 51 (the twenty fifth input being from a dummy tension transducer 59 used as a check on the level of excitation of the active transducers). The transducers are driven by drive circuitry 60. The multiplexed tension inputs are converted to digital signals suitable for the microprocessor by an analogue to digital convertor 52.
The muliplexer 51 is controlled via a six bit word from RAM 46, which i5 sufficient to address the twenty five tension transducers.
Yarn tension in high speed false twist crimping machines may well contain frequency components up to 30 Hz.
A suitable sampling rate is eighty per second, giving a total input of 80 x 25 = 2,000 tension readings per second, or one rading every 500~ s. This can be achieved using a timing cycle as illustrated in Figure 4 as follows:-Al - data held on integrator - -5~ s A2 - multiplexer 51 stepped to next position - 20~ s A3 - data converted from analogue to digital - 30~ s ' ~ ' `
113S3~g 9~
A4 - integrator switched to sample next channel - 5~ s A5 - arithmetic to form average and test for limits - 40~ s A6 - integrator observes tension signal for 400~ s without attention from the micro-processor which can carry out other duties such as broken thread alarms and controlling the data link (see below) to the central processor - 400~s This is repeated for each of the twenty five tension channels Cl, C2, .... C25, and each complete scan, - 15 therefore takes 12.5 ms. The tension signal will be analysed in the microprocessor to determine its average and checked against limits for average tension.
Instantaneous level will also be checked against limits, either one of these tests giving rise, if required, to an alarm condition. Averaging takes, obviously, a few seconds. 256 samples of eight bit data add up to sixteen bits or two eight bit words. Thus, if 256 samples are chosen for averaging, the twenty four tension averages from a bay can be reported to the central processor in 2 x 24 = 48 words. 256 samples takes 3.2 seconds which is adequate for establishing an average tension.
The nine bays are multiplexed on the data link to the . .
central processor 42 which is via a data link controller ~DLC) 54. This converts data to serial form for transmission down a single transmission line and performs parity checks.
Broken thread detection is also monitored in the microprocessor, inputs from twenty four broken thread - :
., ~. :
. :
131 3S38~
10 .
detectors being connected through photo couplers 53 to inputs on the EPROM 44 and RAM 45.
Figure 5 shows how only about half the data link timing cycle is used to report bay data, leaving the other half for transmission of other data along the machine, for example, heater temperatures.
So the system allows very fast scanning of tension -eighty samples per second on each threadline - which is required to catch transient off-limits tensions, while still having capacity to include other machine variables for which additional memory can be provided if required.
This is in contradistinction to prior art tension monitoring systems that scan all two hundred or so threadlines serially, spending several seconds sampling each threadline, so that even quite long period off-limits tensions will pass unnoticed.
Connection of the DLC 54 to the control and display unit 42 is desirably by a light guide coupling 55 with input and output light guides 56, 57. This avoids interference from yarn cutters, temperature controllers and other neighbouring electrical equipment on the machine.
The control and display unit 42 illustrated in Figure
2 comprises the VDU with keyboard 58 for input of control parameters and instructions to an 8085 microprocessor 61 and associated circuitry including a Direct Memory Access (DMA) controller 62 and Programmable Peripheral Interface (PPI) 63. The light guides 56, 57 are connected to the DMA controller 62 via a light guide coupling 64 and an SDLC 65. The 8085 microprocessor 61 has an associated RAM 66 that accepts data and holds it acting as a buffer until it is called for by the 8085 unit 61, and an ROM 67 that holds necessary information for carrying out further tasks such as accepting and analysing data from other ~ ' '' - ':' ,.
~' .. ,. ~ .
~13S38~
11 .
sources such as temperature sensors, shaft speed, traverse speed, draw ratio, false twisting device parameters, over-feeds and so on. The DMA controller 62 acting through the PPI 63 allows rapid access to memories of the central processor and can transfer blocks of data rapidly without programme action from the microprocessor.
This arrangement can be programmed to perform the following tasks:-1. Communication with and control of the monitoring units Ml, M2, ..... M9.
2. Accepting and analysing data from these units.
~' .. ,. ~ .
~13S38~
11 .
sources such as temperature sensors, shaft speed, traverse speed, draw ratio, false twisting device parameters, over-feeds and so on. The DMA controller 62 acting through the PPI 63 allows rapid access to memories of the central processor and can transfer blocks of data rapidly without programme action from the microprocessor.
This arrangement can be programmed to perform the following tasks:-1. Communication with and control of the monitoring units Ml, M2, ..... M9.
2. Accepting and analysing data from these units.
3. Displaying required data on machine efficiency, tension averages, ends down etc.
4. Input of external (e.g. operator's) instructions e.g. tension parameters, limits, data display call-up etc.
A magnetic tape storage unit or other hard copy device 68 is provided for logging the data.
Clearly, modification and additions may be made to the system without departing from the primary object of providing a system for the high speed scanning of tension sensing devices. In addition to activating alarms, the system can also actuate stop motions for individual threadlines or for whole bays (if, for example, second heater temperature is off limits) or for the whole machine in the event, for example, of gear box overheating.
::
A magnetic tape storage unit or other hard copy device 68 is provided for logging the data.
Clearly, modification and additions may be made to the system without departing from the primary object of providing a system for the high speed scanning of tension sensing devices. In addition to activating alarms, the system can also actuate stop motions for individual threadlines or for whole bays (if, for example, second heater temperature is off limits) or for the whole machine in the event, for example, of gear box overheating.
::
Claims (14)
1. A monitoring system for a thread processing machine of the kind in which a plurality of threads is processed in a plurality of similar processing stations, each processing station having a transducer giving an electrical output represen-tative of the value of a processing parameter in that processing station, wherein said monitoring system comprises monitoring units numbering less than the number of said processing stations, each monitoring unit being connected to a respective group of said transducers to receive, process and store information sequentially from the electrical outputs thereof and to scan said respective group of transducers repeatedly, said monitoring units being connected to a common display and control unit for said system.
2. A system according to claim 1, in or for a textile thread processing machine of the kind assembled as a plurality of bays each having a plurality of processing stations, character-ised in that each bay comprises at least one of said monitoring units.
3. A system according to claim 1 or claim 2, character-ised in that a monitoring unit can scan its group of transducers in a time corresponding to a small thread throughput.
4. A system according to claim 1, or 2 characterised by being adapted to monitor thread tension.
5. A system according to claim 1 characterised in that a monitoring unit triggers an alarm when the monitored processing parameters is off limits.
6. A system according to claim 5, characterised by having a facility for adjusting the processing parameter limits.
7. A system according to claim 6, characterised in that said limit adjusting facility is common to all monitoring units.
8. A system according to claim 1, characterised in that a monitoring unit comprises a microprocessor programmed to pass selected information derived from the transducers to a common data processing unit comprised in said display and control unit.
9. A system according to claim 8, in which said com-mon data processing unit can be preset to desired parameter values and limits.
A system according to claim 8 or claim 9, character-ised in that the monitoring units are connected to said common data processing unit by light guides.
11. A system according to claim 1, characterised in that more than one parameter is monitored.
12. A system according to claim 11, characterised in that individual threadline parameters as well as whole machine parameters are monitored.
13. A system according to claim 11 or claim 12, characterised in that different parameters are monitored at dif-ferent time intervals.
14. A system according to claim 1, 2 or 11, character-ised in that each group of transducers monitoring a threadline parameter comprises the same number of transducers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000341767A CA1135384A (en) | 1979-12-12 | 1979-12-12 | Control of thread processing machinery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000341767A CA1135384A (en) | 1979-12-12 | 1979-12-12 | Control of thread processing machinery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1135384A true CA1135384A (en) | 1982-11-09 |
Family
ID=4115823
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000341767A Expired CA1135384A (en) | 1979-12-12 | 1979-12-12 | Control of thread processing machinery |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1135384A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4685179A (en) * | 1983-10-13 | 1987-08-11 | World Tech Fibres, Inc. | Air processing apparatus |
| US4720702A (en) * | 1985-07-03 | 1988-01-19 | Barmag Ag | Method and apparatus for monitoring the tension of an advancing yarn |
| US4720806A (en) * | 1984-03-31 | 1988-01-19 | Barmag Ag | Method and apparaus for centrally collecting measured values |
| US4782565A (en) * | 1983-10-13 | 1988-11-08 | World Tech Fibres, Inc. | Air processing apparatus |
| US5440870A (en) * | 1991-01-17 | 1995-08-15 | Barmag Ag | Method and apparatus of monitoring the quality of a false twist textured yarn |
| WO2016120187A1 (en) * | 2015-01-29 | 2016-08-04 | Oerlikon Textile Gmbh & Co. Kg | Method and device for producing a textured thread |
-
1979
- 1979-12-12 CA CA000341767A patent/CA1135384A/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4685179A (en) * | 1983-10-13 | 1987-08-11 | World Tech Fibres, Inc. | Air processing apparatus |
| US4782565A (en) * | 1983-10-13 | 1988-11-08 | World Tech Fibres, Inc. | Air processing apparatus |
| US4720806A (en) * | 1984-03-31 | 1988-01-19 | Barmag Ag | Method and apparaus for centrally collecting measured values |
| US4720702A (en) * | 1985-07-03 | 1988-01-19 | Barmag Ag | Method and apparatus for monitoring the tension of an advancing yarn |
| US5440870A (en) * | 1991-01-17 | 1995-08-15 | Barmag Ag | Method and apparatus of monitoring the quality of a false twist textured yarn |
| WO2016120187A1 (en) * | 2015-01-29 | 2016-08-04 | Oerlikon Textile Gmbh & Co. Kg | Method and device for producing a textured thread |
| CN107207178A (en) * | 2015-01-29 | 2017-09-26 | 欧瑞康纺织有限及两合公司 | Method and apparatus for manufacturing Texturized silk |
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