EP0153350B1 - Method and installation for monitoring working stations of a textile machine - Google Patents

Abstract

For each monitoring station there is provided a measuring member and a common processor (53) is affected to a plurality of measuring members, which processor groups the signal working processes with the same repetition rates into classes , and intermingles both classes during the progress thereof so that, as to the different monitoring positions, the corresponding signal treatment processes are repeated at least approximately periodically. It is thus possible to distribute the work load of the processors (53) without having to wave the processing periodicity; it is also possible with a given processor to simultaneously serve more monitoring stations in the case of a predetermined yarn speed.

Description

The invention relates to a method for the simultaneous monitoring of the yarn quality at a plurality of similar monitoring points of a textile machine, in which for each monitoring point a measuring element and processors assigned to the measuring elements are used for processing the signals supplied by the measuring elements and a common processor is assigned to several measuring elements.

DE-A-30 05 746 and EP-A-50 83 disclose methods of this type for monitoring process parameters on false twist crimping machines or on ring spinning machines. A specific sensor is used for each operating state or process parameter, the output signal of which is subjected to a specific signal processing process.

Processes of the type mentioned at the outset are used, inter alia, on yarn cleaning and yarn quality monitoring systems for alternative spinning processes such as rotor spinning and the like. In addition to the known yarn defects, such as short thick spots, coarse threads and thin spots, periodic and aperiodic error chains, number deviations and deviations in the yarn uniformity can also occur. All of these types of errors can be derived from the signal of one type of measuring device, which are subjected to various signal processing processes.

When using known methods of digital signal processing to analyze the signals from the measuring elements, it is necessary, for example for the detection of short thick spots as well as periodic and aperiodic error chains, to run suitable algorithms for this every 5 mm per length of the yarn that has passed through, using measured values that are used for average cross-section or diameter of about 5 mm of yarn are proportional.

For the detection of coarse threads or long thin spots, it is sufficient to use suitable algorithms only every 10 to 20 cm using average values of the yarn cross-section or diameter over the last 10 to 20 cm, and the detection of number deviations is only useful if Analysis average values over several meters can be used. The algorithms or signal processing processes mentioned must therefore run per monitoring point according to a fixed cycle, some with a high repetition rate, others with one or more orders of magnitude slower.

If systems of the type described in DE-A-30 05 746 or in EP-A-50 83 were to be used for the yarn cleaning and yarn quality monitors mentioned, then the capacity of the processors would have to cope with the load peaks, that is, the signal processing processes with the highest repetition rate, which would make the arrangement extremely expensive. On the other hand, if the costs remain within a reasonable range, then certain types of errors may not have to be recorded.

The invention is intended to enable inexpensive monitoring of all types of errors.

This object is achieved with the features specified in the characterizing part of claim 1.

A further considerable reduction in the complexity of the implementation in terms of circuit technology can be achieved by separating the functions of error analysis and error handling between stationary operation and start-up operation.

The invention further relates to a device for performing the above-mentioned method, each with a measuring element for the individual monitoring points and with a plurality of measuring elements assigned to processors for processing the signals supplied by the measuring elements, the processors being assigned a common central device and with them via a Communication channel is connected, and each processor has a multiplexer controlled by a timer for cyclic sampling of the output signals of the measuring elements assigned to this processor.

The device according to the invention is characterized by the features specified in the characterizing part of claim 9.

• Fig. 1a, 1b, 1c einen schematischen Ausschnitt aus einem zeitlichen Ablauf der wichtigsten Signalverarbeitungsprozesse, und
• Fig. 2 das Blockschema einer möglichen Ausführungsform einer erfindungsgemässen Vorrichtung.

The invention is explained in more detail below using an exemplary embodiment and the figures; show it :

• 1a, 1b, 1c a schematic section from a chronological sequence of the most important signal processing processes, and
• Fig. 2 shows the block diagram of a possible embodiment of a device according to the invention.

The timing diagram of FIGS. 1a to 1c, which are to be thought of as lined up on their narrow sides, shows the most important signal processing processes running in a processor. It is assumed that this processor is assigned to a group of 24 monitoring points and thus measuring heads.

In the upper zone 100 of the flowchart, those processes are shown which are used to analyze the signals derived from the measuring heads and which are assigned to the monitoring points 1 to 24 entered on the ordinate. In the lower part, the chronological arrangement of processes for auxiliary and additional functions 102 to 111 is in a first line 101, and the chronological arrangement of processes 202 to 204 for preparation and processing in a second line 201 tion of messages in connection with the mutual exchange of results between different processes, in a third line 301 the timing of waiting time intervals 302 to 311 for synchronization characters and in lines 401, 501 and 601 the timing of these synchronization characters 402, 502, 602 are shown .

According to the legend 30 in FIG. 1a, the processes shown in zone 100 are divided into three classes characterized by different hatching: processes 31 of class I, processes 32 of class II and processes 33 of class 111. The synchronization symbol 402 is encountered in each case the time-critical processes 31 (class I), the synchronization symbol 502 the time-critical processes 32 (class II) and the synchronization symbol 602 the time-critical processes 33 (class 111). These synchronization characters 402, 502 and 602 occur periodically, with a periodicity T _o corresponding to a yarn length of 5 mm.

The processes 31 of class I relate, among other things, to the analysis of short yarn defects which require a sampling rate of 5 mm yarn run, for example, short thick spots as well as periodic and aperiodic error chains.

The processes 32 of class II, which are designated 701, 702 and 703, run with respect to the individual monitoring points with a repetition rate which is only 1/8 of that of the processes 31. These processes include analysis of coarse threads and long thin spots. In relation to the thread run, they therefore run at a repetition rate of 4 cm. This reduced repetition rate is achieved (while maintaining the periodicity per monitoring point) by alternating the monitoring points 1 to 3, 4 to 6, 7 to 9, ....., 22 to 24.

Finally, processes 33 of class 111, of which process 801 is drawn, run at a repetition rate that has been reduced again to 1/8, that is to say every 32 cm in relation to the yarn run. The following are possible here: analyzes of number deviations as well as the sending and receiving of data packets in communication with the central control unit and possibly other groups.

The sending and receiving of data packets with processes 33 of class III is to be understood in such a way that a packet is exchanged (sent or received) each time in the rhythm of the repetition rate of class I. According to the example shown, each can be a permanently formatted package from a structured stock of 64 such packages, which are exchanged cyclically in succession. A package that contains similar information (setting parameters or shutdown commands for certain monitoring points) accordingly only comes every 64 times, ie. H. every 32 cm yarn run for transmission. This principle can be varied within wide limits and adapted to current needs without deviating from the inventive idea.

The various auxiliary functions 102 to 111 shown in line 101 are necessary to carry out the extensive multiplexing process: to switch to the individual monitoring points, to reduce data (averaging, generalized: decimation), to initialize and to carry out and analyze the data traffic, etc. Under the assumption that these additional functions are carried out by the processor mentioned, they must also be expediently assigned to one of the three classes.

For example, the reduction of the data rate to 1/8 and the associated decimation is an auxiliary function that has to be carried out separately for the yarn signal of each monitoring point. A corresponding decimation algorithm must therefore be run before or after the respective class I signal analysis algorithm as preparation for the class II signal analysis. The same applies to data reduction and preparation of class IIL signal analysis.

As auxiliary and additional functions that cannot be assigned to the individual monitoring points, the management of address pointers, of memory locations for the intermediate storage of intermediate results and the waiting for synchronization signals and their acceptance are to be mentioned.

For example, the auxiliary function 102 prepares the waiting character interval 302 for the synchronization character 402, which then triggers the processes 31 of class I for the 24 monitoring points. The next following synchronization symbol 402 for the processes 31 is then received after the period T _o corresponding to a yarn length of 5 mm, whereupon the processes 31 are in turn triggered for all 24 monitoring points.

The auxiliary function 103 prepares the waiting character interval 303 for the synchronization character 502, which triggers the processes 32 of class II designated 701 for the monitoring points 1 to 3. The synchronization symbol 502 following after the period T _o then triggers the processes 32 designated 702 for the monitoring points 4 to 6, and so on.

The block diagram of FIG. 2 shows a central processing unit 51 and a processor 53 connected to it via a communication channel 80, generally several processors 53 being connected to the communication channel 80 and each of these processors 53 serving a number of similar monitoring points.

In the exemplary embodiment shown, the processor 53 is fed by 24 (analog) yarn signals 55, which are emitted by sensors (measuring heads) of known technology attached to the textile machine. The processor 53 has 24 outputs 56 on the machine for shutdowns and n times 24 outputs 57 for alarm signals. One output 56 for shutdown and n outputs 57 for alarm signals are therefore provided for each monitoring point. The outputs 56 are used for Interruption of the fiber supply or to trigger a cleaner cut, the outputs 57 serve to indicate the type of yarn defects discovered at the corresponding monitoring point, the state of the monitoring point and similar parameters and information.

The processor 53 is constructed using known microprocessor technology and contains at its heart a microprocessor 58, which is connected to an address, data and control line bus (A, D, S) and receives its clock from an external timer 59. A decoder 60 is used to decode addresses of individual modules. The yarn signals are passed via an analog multiplexer 61 controlled by the timer 59 to an A / D converter 62, from where they are called up by the microprocessor 58. The shutdown and alarm signals 56, 57 are emitted to the outside world via a driver 63.

A special communication processor 64 handles the packet-by-packet data traffic between communication channel 80 and microprocessor 58. Communication with the central unit 51 takes place serially on a separate line for sending and receiving, communication with the microprocessor 58 takes place in parallel via transmit and receive registers provided by the microprocessor 58 loaded or read. Transmission and reception are controlled by timer 59.

The functions performed by the processor 53 are those which are incurred in the stationary running operation of the textile machine. For example, if this textile machine is a rotor spinning machine with typically 200 or more spinning positions, then it processes the same yarn quality on all spinning positions, i.e. H. the values of the setting parameters are the same for all spinning positions. The rotor spinning machine is operated by a single moving piecing machine, so that piecing or splicing, i.e. a function during the start-up or in the steady-state running operation of the spinning machine, only takes place at a single spinning station. For this reason, the measuring head of the respective spinning station is connected to the central unit 51 in the start-up state and, after reaching the steady-state operation, is switched off and switched back to the corresponding processor 53. The monitoring point of a machine position in the start-up state is connected to the central unit 51 via a relay bank 65 controlled by the microprocessor 58; the yarn signal 66 is sent to the central unit 51 as an analog signal.

The functions of error analysis and error handling in steady-state operation can be divided into two categories: In processes of a first category that run synchronously with the Garniauf, this is the analysis for suspected errors (processes of the three classes in zone 100 of FIG. 1), and in processes of a second category that do not necessarily run synchronously with the garnish, these are the decisions about interventions to be initiated and alarms to be triggered. The processes in the first category are carried out by the processor 53, those in the second category by the central unit 51, which sends appropriate signals for an alarm 67 and commands for interventions 68 to the central control of the textile machine.

The central unit 51 is constructed using known microprocessor technology, so that a special explanation is unnecessary here. Connections to input stations, data systems, etc., which are known from the prior art and are readily possible, are not shown since they do not form the subject of the invention.

The communication channel 80 is designed according to FIG. 2 as a bus system. The messages to be exchanged between the processor 53 and the central processing unit 51 (FIG. 1, line 201) are transmitted digitally and serially on two direction-separated lines 82, 83. A special clock line 81 is used for synchronization. The analog yarn signal 66 of a machine position in the start-up phase is transmitted to the central processing unit 51 as an analog voltage via a common line 84.

The physical separation of the functions "error analysis and error handling in stationary operation and" error analysis and error handling in startup mode "brings a considerable reduction in the complexity of the circuitry implementation compared to conventional methods: The scanning of the yarn signals must be in a rigid cycle (every 5 to 10 mm yarn run ) proceed, whereby the error analysis during running is carried out according to relatively simple criteria and the error analysis in the start-up state (examination for cut double threads, coarse threads and thin spots) is more complicated and more complex. The reduction in effort in the case of the aforementioned separation of the two functions results from the fact that only one device is required for the more complex function.

A further reduction in effort results from the division of the function «error analysis and error handling in stationary running operation into processes of the first category running synchronously with the yarn run (analysis for suspected errors) and into processes of the second category not necessarily synchronously running (decision on interventions to be initiated and alarms to be triggered). Because the analysis of suspected errors is based on very simple criteria and usually ends negatively. On the other hand, the criteria for triggering an alarm and / or for switching off a machine position require additional features that can only be taken into account if a positive error is suspected. Although the triggering of shutdowns and alarms as well as the scanning of the yarn signals is also time-critical, delays of 10 to 20 cm and more (based on the yarn sequence) are quite permissible, since at least 1 m of yarn is removed when the machine is turned off and then restarted . Since there are also yarn defects in the textile machines in question are very rare events, it makes sense to deal with the suspected errors in the common central unit 51, which is responsible for several processors 53 and many monitoring stations.

There are cheap one-chip microprocessors available on the market today that are ideal for implementation. In the textile machines under consideration, the yarn run-off speeds today are a maximum of about 150 m / min. This allows the operation of 12 to 24 monitoring points with a single processor, if this is only used for the analysis of the most time-critical criteria (suspected errors). Such a number of monitoring points (machine positions) also makes sense from a textile point of view and corresponds to a normal «section».

The additional effort for the exchange of the data packets between the two categories of processes is minimal, since there are cheap one-chip microprocessors on the market today, where the communication processors required for bit-serial transmission are hardware-integrated on the same chip. The specified data rates are so high that a bus procedure is possible without any problems.

The nesting of the suspected error analysis on long coarse threads and thin spots enables efficient handling of these types of errors. Due to the sampling theorem (Nyquist), a sampling and processing rate in the order of magnitude of only 5 to 10 cm of yarn run is necessary for digital signal processing. The fact that only a part of all of the monitoring points is processed alternately in between means that the load on the processor 53 used can be balanced over time without having to forego the periodicity of the processing. The practical consequence of this is that a given processor can process more monitoring points at the same time with a given yarn running speed than without this nesting.

Claims (9)

1. Method for the simultaneous monitoring of yarn quality at a plurality of similar monitoring stations of a textile machine, wherein a measurement device for each the monitoring station as well as processors associated with measurement devices are used for the processing of the signals delivered by the measurement devices, and wherein a common processor is associated in each case with a plurality of measurement devices, characterised in that for one run of the various signal processing processes for the individual monitoring stations with different repetition rates, the signal processing processes with the same repetition rates are combined into classes (31, 32, 33) and these classes are so interleaved during their running that, related to the individual monitoring stations, the corresponding signal processing processes are repeated at least approximately periodically.

2. Method in accordance with claim 1, characterised in that the interleaving of the individual classes (31, 32, 33) of signal processing processes takes place in such a way that processes with the highest repetition rate run cyclically for all monitoring positions, and those with a slow repetition rate run in each case for only a few monitoring stations.

3. Method in accordance with claim 2 for analysing the signals of the measurement devices by the processors (53) for features of short and long faults, characterised in that the analysis for short and long faults is carried out in each case with a frequency which approximately corresponds to the inverse ratio of the reference lengths for the respective features.

4. Method in accordance with claim 3, characterised in that the analyses of the signals of the measurement devices for features of long yarn faults are carried out with a scanning rate which is artificially reduced relative to the yarn length and with corresponding average values ; and in that the reduction factor for the scanning rate corresponds approximately to the ratio between the reference lengths for the features of the long and short faults.

5. Method in accordance with claim 4, characterised in that per scanning interval (To), all monitoring stations are analysed in a cyclical sequence for the features of short faults and in accordance with the reduction factor for the scanning rate, in each case only some of the monitoring stations are analysed individually and among themselves in a cyclical sequence for the features of long faults.

6. Method in accordance with claim 5, characterised in that the signals of the measurement devices are analysed for features of extremely long yarn faults with a scanning rate which is again reduced.

7. Method in accordance with one of the claims 1 to 6, characterised in that one uses the processors (53) for processing the signal processing processes which are combined into mutually interleaved classes (31, 32, 33) for fault analysis and for dealing with faults in steady state running operation ; and in that one provides an additional special arrangement (51) for the analysis of faults and for dealing with faults during start-up and the initial steady state running operation, onto which one switches each monitoring station which is in a starting state, and the switches it away again after reaching the steady state running operation.

8. Method in accordance with claim 7, characterised. in that one splits up the signal processing processes for dealing with faults and for the analysis of faults in steady state running operation into those which take place synchronously with the movement of the yarn, and into those which do not necessarily take place synchronously with the movement of the yarn ; and in that one deals with the last category of signal processing processes with the additional special arrangement (51).

9. Apparatus for carrying out the method of claim 7, with one measurement device for the individual monitoring stations and with processors which are in each case associated with a plurality of measurement devices for processing the signals delivered by the measurement devices, with a common central apparatus being associated with the processors and being connected with the latter via a communication channel, and with each processor having a multiplexer controlled by a clock for the cyclical scanning of the output signals of the measurement devices associated with this processor; characterised in that the processors (53) are provided for fault analysis and for dealing with faults in the steady state running operation, and the central apparatus (51) is laid out for the analysis of faults and for dealing with faults during starting up and at the start of the steady state running operation ; and in that the signals of the measurement device of a monitoring station in the starting up state are transmitted to the central apparatus via the respective communication channel (80).

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