EP1602761A2

EP1602761A2 - Setting device for loom

Info

Publication number: EP1602761A2
Application number: EP05008280A
Authority: EP
Inventors: Koki Yamazaki; Emiko Kitamura; Ryosuke Fujimori
Original assignee: Tsudakoma Industrial Co Ltd
Current assignee: Tsudakoma Corp
Priority date: 2004-05-24
Filing date: 2005-04-15
Publication date: 2005-12-07
Also published as: KR20060042375A; CN1702216A; JP2005336624A

Abstract

A setting device (20) for a loom includes error-detecting means (21, 22) for comparing a yarn signal with a threshold level and generating an error signal based on the comparison result; a loom controller (40) for stopping the loom in response to the error signal; a setting-display unit (41) connected with the error-detecting means (21, 22) and the loom controller (40) and receiving setting data including the threshold level, the setting-display unit (41) displaying data from the loom controller (40) on a display portion (43); and a memory unit (30) connected with the setting-display unit (41) and provided for storing the yarn signal for a predetermined time period. The setting-display unit (41) reads a waveform of the yarn signal stored in the memory unit (30), and displays the waveform of the yarn signal and the threshold level on the display portion (43) in an overlapping manner.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a setting device for a loom, in which settings of various types can be performed while referring to a waveform of a yarn signal and a threshold level for the yarn signal.

2. Description of the Related Art

Japanese Unexamined Patent Application Publication No. 62-184148, for example, discloses a reflective weft-sensor unit provided in a fluidic-jet-type loom. Such a weft-sensor unit emits light towards a weft-traveling path and compares the level of reflected light (yarn signal) with a predetermined threshold level. Based on the comparison result, the weft-sensor unit determines whether or not a weft-insertion process has been properly performed. If the weft-sensor unit has difficulty in detecting the level of a yarn signal that indicates the presence of a weft yarn, the loom may stop due to an unknown reason or a missed pick of weft yarn may be formed. For this reason, it is necessary to adjust the threshold level in a more highly accurate manner. For example, if the dents of the reed are closely arranged, there may be cases where a signal fluctuation may be caused due to the vibration of the dents.

Such an adjustment of the threshold level is commonly performed using a measuring instrument such as an oscilloscope, and may be problematic in that the adjustment process takes too much time for someone who is not experienced in using such an instrument. Accordingly, it is desired that the waveform of the yarn signal and other related data can be observed during the adjustment process.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a setting device in which a threshold level for a yarn signal can be accurately adjusted while observing a waveform of the yarn signal.

The present invention provides a setting device for a loom, which compares a yarn signal with a predetermined threshold level and generates an error signal based on the comparison result, the error signal being used for stopping the loom. Such a setting device includes error-detecting means for comparing the yarn signal with the threshold level and generating the error signal based on the comparison result; a loom controller for stopping the loom in response to the error signal; a setting-display unit including an input portion and a display portion and connected with the error-detecting means and the loom controller, the setting-display unit receiving setting data including the threshold level via the input portion, the setting-display unit displaying data from the loom controller on the display portion; and a memory unit connected with the setting-display unit and provided for storing the yarn signal for a predetermined time period. The setting-display unit reads a waveform of the yarn signal stored in the memory unit, and displays the waveform of the yarn signal and the threshold level on the display portion in an overlapping manner.

Accordingly, by displaying the waveform of the stored yarn signal and the threshold level on the display portion in an overlapping manner, the magnitude relationship between the waveform of the yarn signal and the threshold level can be checked visually through the setting device for the loom. This solves the problem of, for example, the stopping of the loom due to an unknown reason or the missed pick of weft yarn, and allows the threshold level to be set in a highly accurate manner.

Furthermore, the waveform of the yarn signal stored in the memory unit preferably corresponds to at least one pick of yarn. Moreover, when the loom is a multiple-color weft-insertion type, the memory unit preferably stores the waveform of the yarn signal and a weft-selection condition, and the setting-display unit preferably displays the waveform of the yarn signal and the threshold level corresponding to an input type of weft yarn.

Accordingly, since the waveform of the yarn signal stored in the memory unit corresponds to at least one pick of yarn, the characteristic of one repeat cycle can be observed, and moreover, the waveform of the yarn signal corresponding to a particular pick from a plurality of picks can be read and displayed. Furthermore, in a multiple-color weft-insertion loom, even if the stopping of the loom due to an unknown reason or the missed pick of weft yarn occurs during processing of a particular type of weft yarn, the magnitude relationship between the waveform of the yarn signal and the threshold level corresponding to the input type of weft yarn can be readily checked since the waveform of the yarn signal is stored together with the weft-selection condition.

The error-detecting means preferably includes two weft-sensor units disposed distant from each other along a weft-traveling path, each weft-sensor unit having a detection region on the weft-traveling path. Moreover, the yarn signal preferably includes at least one of yarn signals output from the respective weft-sensor units. Furthermore, the setting-display unit preferably displays the waveform of the yarn signal and the threshold level corresponding to one of cycles of weft insertion in which the error signal is generated.

Accordingly, since the yarn signal includes at least one of yarn signals output from the respective weft-sensor units, the inserted condition of the weft yarn can be readily checked, and moreover, the setting process is simplified. Furthermore, by displaying the waveform of the yarn signal and the threshold level corresponding to one of cycles of weft insertion in which the error signal is generated, the cause of the error can be quickly identified.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram illustrating a relevant section of a weft-insertion device in a loom;

Fig. 2 is a block diagram illustrating, for example, a setting device for a loom according to the present invention;

Fig. 3 is a schematic diagram of a display portion according to the present invention, in which an example of display is illustrated; and

Fig. 4 is a schematic diagram of the display portion according to the present invention, in which an example of display of levels is illustrated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1 illustrates a relevant section of a weft-insertion device 1 in a fluidic-jet-type loom, such as an air jet loom. In Fig. 1, a weft yarn 4 is pulled out from a yarn supplier 3 supported by a holder 2, and is guided to, for example, a rotatable weft-guide 6 provided in a weft measuring/holding drum unit 5. While a stopper pin 8 holds the weft yarn 4 on the outer periphery of a drum 7 in a stationary state, the rotatable weft-guide 6 rotates around the drum 7 so as to wind the weft yarn 4 around the outer periphery of the drum 7. Thus, the weft yarn 4 is measured for a predetermined length required for one cycle of weft insertion, and is held until the weft insertion process for the measured weft yarn 4 is performed.

When the weft insertion process is to be performed, the stopper pin 8 is driven by an operating unit 9 so as to be shifted away from the outer periphery of the drum 7. The weft yarn 4 wound around the drum 7, that is, the predetermined length of weft yarn 4 required for one cycle of weft insertion, is thus released from the drum 7 and is guided to a main nozzle 10, which functions as a weft-insertion nozzle.

For each cycle of weft insertion, the main nozzle 10 discharges an air jet 12 into a shed 14 formed between sets of warp yarns 13 for a predetermined time period so that the weft yarn 4 with the predetermined length for one cycle of weft insertion is inserted into the shed 14. Thus, the weft yarn 4 travels through a weft-traveling path in the shed 14. The pressure value of the air jet 12 is set at an appropriate value via pressure-adjustment means (not shown).

Furthermore, multiple groups of sub-nozzles 11 are arranged in the direction of weft insertion. While the weft yarn 4 travels through the weft-traveling path in the shed 14, the multiple groups of sub-nozzles 11 discharge air jets 15 toward the traveling weft yarn 4 at once or in a relay manner. In the latter case, that is, discharging in a relay manner, the air jets 15 are discharged according to the traveling rate of the weft yarn 4. Consequently, this gives momentum to the weft yarn 4 traveling in the shed 14 in the direction of weft insertion. The pressure value of the air jets 15 are also set at an appropriate value via pressure-adjustment means (not shown).

The discharging of air jet 12 and air jets 15 from the main nozzle 10 and the multiple groups of sub-nozzles 11 achieves proper weft-insertion of the weft yarn 4. The inserted weft yarn 4 is then beaten against a cloth fell 18 of cloth 17 with a reed 16. After the weft yarn 4 is woven into the cloth 17, a trailing end of the inserted weft yarn 4 near the main nozzle 10 is cut with a yarn cutter 19 so that the inserted weft yarn 4 is cut off from the weft yarn 4 remaining in the main nozzle 10.

The inserted condition of the weft yarn 4 is detected by a first weft-sensor unit 21 and a second weft-sensor unit 22, which define error-detecting means. The first weft-sensor unit 21 is provided with a sensor 24 which faces the weft-traveling path at a position near the leading end of the inserted weft yarn 4. The sensor 24 detects the weft yarn 4 at this position, and such a position is where a properly inserted weft yarn 4 should reach. On the other hand, the second weft-sensor unit 22 is provided with a sensor 25 which faces the weft-traveling path at a position distant from the leading end of the inserted weft yarn 4. The sensor 25 detects a leading end of a long-pick weft yarn 4 or a segment of a weft yarn 4 accidentally cut and blown due to the air jets. The output signals from these

sensors

24 and 25 are sent to a setting device 20 for a loom according to the present invention.

The

sensors

24 and 25 of the respective first and second weft-

sensor units

21 and 22 face the slits formed between the dents of the reed 16 (i.e. slits formed between dents of a profile reed) in a manner such that the

sensors

24 and 25 do not hit with the beating motion of the reed 16. Generally, each of the

sensors

24 and 25 is a projecting/receiving (reflective) sensor containing both a projector and a photoreceiver. Each projecting/receiving (reflective) sensor has a detection region on the weft-traveling path, and when the sensor detects the weft yarn 4 on the weft-traveling path, the sensor generates an electric output signal corresponding to the amount of reflected light received from the weft yarn 4. Alternatively, the

sensors

24 and 25 may be transmissive sensors or other types of sensors.

Fig. 2 illustrates the setting device 20 according to the present invention. In Fig. 2, the output signal from the sensor 24 is amplified by an amplifier circuit 26 included in the first weft-sensor unit 21 so as to generate a yarn signal S1. The yarn signal S1 is then input to a memory unit 30 and to a comparator 27. The amplification degree of the amplifier circuit 26 is preliminarily set at a value suitable for each type of weft yarn via an amplification setting unit 28.

The comparator 27 receives the yarn signal S1 and a threshold level L1 used for determining whether the inserted weft yarn 4 is present or not present. The comparator 27 compares the magnitude relationship between the yarn signal S1 and the threshold level L1. The threshold level L1 is preliminarily set at a level suitable for each type of weft yarn via a threshold-setting A/D converter 29.

In a case where threshold level L1 ≤ yarn signal S1, the comparator 27 generates, for example, an H-level signal S6 indicating that the weft yarn 4 is present, and sends the H-level signal S6 to a first input terminal of a determination circuit 38 included in a weft-insertion determination circuit-unit 31. In contrast, in a case where threshold level L1 > yarn signal S1, the comparator 27 outputs an L-level signal S6 indicating that the weft yarn 4 is not present. As an alternative to the example shown in Fig. 2, in which the yarn signal S1 generated by amplifying the output signal from the sensor 24 is directly used for determining whether the weft yarn 4 is present or not present, a differentiator or an integrator (not shown) may be provided between the amplifier circuit 26 and the comparator 27, such that the presence of the weft yarn 4 may be determined based on a differential signal of the yarn signal S1 or an integral signal obtained within a predetermined detection period. In that case, the output signal from the differentiator or the integrator may be treated substantially equivalent to the yarn signal S1.

On the other hand, an encoder 34 linked with a main shaft 33 of the loom generates a -signal indicating an angle  of the main shaft 33, and sends the -signal to a timing-signal generator 35. The timing-signal generator 35 receiving the -signal generates an H-level weft-detection timing signal S5 within a detection period T1 of the weft yarn 4, for example, a period in which the angle  of the main shaft 33 is from 200° to 290°. The timing-signal generator 35 then sends the timing signal S5 to a second input terminal of the determination circuit 38 and to a resetting circuit 36 and a timing-outputting circuit 37 included in the weft-insertion determination circuit-unit 31. On the other hand, the -signal is also sent to the memory unit 30.

The determination circuit 38 receives the timing signal S5 and the H-level or L-level signal S6. If the H-level signal S6 is input to the determination circuit 38 during the period in which the weft-detection timing signal S5 is generated, the determination circuit 38 determines that the weft insertion is properly performed and thus maintains an output signal from its output terminal at L level. In contrast, if the L-level signal S6 is input to the determination circuit 38 during the period in which the timing signal S5 is generated, the determination circuit 38 determines that an error has occurred in the weft insertion process, and outputs an H-level signal from its output terminal. The output signal from the determination circuit 38 is sent to a logic-signal generator 39. If the H-level signal is input to the logic-signal generator 39, the logic-signal generator 39 generates an error signal S2 at a timing of receiving the leading edge of a signal from the timing-outputting circuit 37, the signal being output from the timing-outputting circuit 37 after the main shaft 33 reaches the final angle (290°) in the detection period T1. Specifically, the error signal S2 is generated for stopping the operation of the loom due to an improper weft insertion, and is sent to a loom controller 40. Thus, the loom controller 40 applies brake on a driving motor (not shown) so as to stop the operation of the loom.

The determination circuit 38 is reset at a timing of receiving the leading edge of a reset signal from the resetting circuit 36, the reset signal being output from the resetting circuit 36 after the main shaft 33 reaches the start angle (200°) in the detection period T1. The reset determination circuit 38 then prepares for the subsequent cycle of weft insertion. On the other hand, after the loom recovers from what had caused the loom to stop, the logic-signal generator 39 is reset via a switch 23 operated by an operator (i.e. user), or alternatively, may be reset by, for example, generating an operation signal.

In the above example, if once the signal S6 reaches the H-level during the input period of the weft-detection timing signal S5, the weft-insertion determination circuit-unit 31 determines that the weft-insertion is properly performed. Alternatively, other determination methods are permissible. For example, the following determination conditions may be applied for determining whether the weft insertion is properly performed: a condition in which the proper performance of weft insertion is determined when the signal S6 reaches the H-level at the final point of the input period of the weft-detection timing signal S5; or a condition in which the proper performance of weft insertion is determined when the signal S6 continues to be at the H-level for a predetermined time period. These determination conditions may be selected for each type of weft yarn 4 used, or may be applied by combining two or more conditions.

Furthermore, the amplification degree set in the amplification setting unit 28 or the threshold level set in the threshold-setting A/D converter 29 may be adjusted according to the type of weft yarn (for example, the color or the thickness of weft yarn). Furthermore, in a multiple-color weft-insertion loom, the circuit structure may be formed in a manner such that the determination condition, the amplification degree, and the threshold level mentioned above are selected based on a selection signal of the weft yarn 4. Moreover, the determination process by the comparator 27 and the weft-insertion determination circuit-unit 31 for determining whether or not the weft insertion is properly performed may alternatively be achieved by using a microcomputer or software. In that case, the amplification degree, the threshold level, or the determination condition may be adjustable via a display unit 41 used also as a setting unit for the loom.

On the other hand, although the internal structure of the second weft-sensor unit 22 defining the error-detecting means is not shown in the drawings, the second weft-sensor unit 22 has substantially the same structure as the first weft-sensor unit 21. Specifically, the output signal from the sensor 25 is sent to an amplifier circuit contained in the second weft-sensor unit 22, and the amplifier circuit outputs a yarn signal S4 to, for example, the memory unit 30. At the same time, the second weft-sensor unit 22 compares the yarn signal S4 with a threshold level L2. Based on the comparison result, in a case where the threshold level L2 s the output signal from the sensor 25, the second weft-sensor unit 22 determines that a cut-and-blown segment of a weft yarn 4 or the leading end of a long-pick weft yarn 4 has been detected. Thus, the second weft-sensor unit 22 generates an error signal S3 so as to respond to the improper weft insertion, and sends the error signal S3 to the loom controller 40. In this case, the loom controller 40 stops the operation of the loom if necessary.

The loom controller 40 is connected with the setting-display unit 41 in a communicable manner, and the setting-display unit 41 is connected with the memory unit 30 also in a communicable manner. As mentioned above, the first weft-sensor unit 21 defining the error-detecting means compares the yarn signal S1 with the predetermined threshold-level L1; generates the error signal S2 based on the comparison result; and then sends the error signal S2 to the loom controller 40. In this case, the loom controller 40 stops the operation of the loom in response to the error signal S2. On the other hand, the second weft-sensor unit 22 also defining the error-detecting means compares the yarn signal S4 obtained from the sensor 25 with the predetermined threshold level L2; generates the error signal S3 based on the comparison result; and sends the error signal S3 to the loom controller 40. In this case, the loom controller 40 stops the operation of the loom if necessary in response to the error signal S3.

On the other hand, the memory unit 30 stores the yarn signal S1 from the first weft-sensor unit 21, the yarn signal S4 from the second weft-sensor unit 22, and the -signal. In addition to these signals, if the loom is a multiple-color weft-insertion type, the memory unit 30 receives a weft-selection signal S8 and stores corresponding waveforms of the yarn signals S1 and S4 for at least one pick and a weft-selection condition. The waveforms and the weft-selection condition are stored for a predetermined time period. On the other hand, the setting-display unit 41 is connected with the threshold-setting A/D converter 29 in the first weft-sensor unit 21, the second weft-sensor unit 22, and the loom controller 40. Thus, the setting-display unit 41 receives setting data including at least the threshold levels L1 and L2, and displays data, such as control data from the loom controller 40, on a display portion 43 contained in the setting-display unit 41.

Although the details of the structure of the setting-display unit 41 are not illustrated in the drawings, the setting-display unit 41 includes an input portion 44 for inputting setting values for the loom; the display portion 43 for displaying, for example, data from the loom controller 40 and yarn-signal waveforms (which will be described below in detail) by using characters, numerals, and graphs; a CPU (not shown) which is connected with the input portion 44, and is provided for controlling the display portion 43 and for controlling the sending and receiving of data between the memory unit 30 and the loom controller 40 connected with each other via a port (not shown); and a memory portion (not shown) for storing, for example, a software program used for controlling the CPU.

Various setting values for devices included in the loom may be input to the setting-display unit 41. For example, the setting values may include pressure values and timing values for discharging air jets from the main nozzle 10 and the sub-nozzles 11; a warp-tension setting value for a warp-tension controller; threshold levels to be compared with the yarn signals S1 and S4 in the respective first weft-sensor unit 21 and second weft-sensor unit 22; and "H1 timing" and "H2 timing" values to be used as weft-detection timings for the respective first weft-sensor unit 21 and second weft-sensor unit 22. The setting-display unit 41 has first and second output terminals respectively connected with the input terminals of the two threshold-setting A/D converters 29 included in the respective first weft-sensor unit 21 and second weft-sensor unit 22. Thus, the setting-display unit 41 outputs threshold signals S9a and S9b respectively from the first and second output terminals to the two threshold-setting A/D converters 29. The input portion 44 and the display portion 43 may be provided separately, but are preferably integrated to form a touch-screen setting unit having both an input function and a multi-color display function.

Fig. 4 illustrates an example in which such a touch-screen setting unit is used. The threshold levels to be compared with the yarn signals S1 and S4 in the first weft-sensor unit 21 and the second weft-sensor unit 22 respectively correspond to "H1 level" and "H2 level". For changing the setting of each of the threshold levels, a corresponding level bar may be moved by touching the corresponding icon displayed on the screen so that the threshold level is increased or decreased from the currently set level in a level-by-level manner. Consequently, the setting-display unit 41 outputs an electric signal corresponding to the newly-set threshold level to the corresponding A/D converter 29. The A/D converter 29 then sends the corresponding threshold signal S9a or S9b to the corresponding comparator 27.

In a case where the loom is a multiple-color weft-insertion type, multiple weft-insertion devices 1 are provided for corresponding types of weft yarns. A weft-selection-signal generator 42 receives a timing signal S7 and generates the weft-selection signal S8 based on a weft-selection procedure preliminarily set in the weft-selection-signal generator 42. The weft-selection-signal generator 42 then outputs the weft-selection signal S8 to the memory unit 30, whereby one of the weft-insertion devices 1 (the weft measuring/holding drum unit 5 or the main nozzle 10 of the corresponding weft-insertion device 1) selected in response to the weft-selection signal S8 is activated.

An operator may input data necessary for the operation of the loom by operating the input portion 44 in the setting-display unit 41. When necessary, the setting-display unit 41 reads waveforms of the yarn signals S1 and S4 stored in the memory unit 30 and displays the waveforms of the yarn signals S1 and S4 and the corresponding threshold levels L1 and L2 on the display portion 43 in an overlapping manner.

In a multiple-color weft-insertion loom, the memory unit 30 stores an input logic for weft selection and the waveforms of the yarn signals S1 and S4. On the other hand, the setting-display unit 41 selectively displays at least one of the waveforms of the yarn signals S1 and S4 and at least one of the threshold levels L1 and L2 corresponding to the type of weft yarn input by an operator. Where necessary, the setting-display unit 41 may display the waveforms of the yarn signals S1 and S4 and the threshold levels L1 and L2 corresponding to a cycle of weft insertion in which the error signals S2 and S3 are generated. Furthermore, in a case where the loom is a multiple-color weft-insertion type, the threshold levels L1 and L2 to be compared with the yarn signals S1 and S4 are adjustable according to each type of weft yarn 4 used, and are preferably selected for each selected type of weft yarn 4. In such a case, the threshold levels L1 and L2 to be displayed together with the yarn signals S1 and S4 on the display portion 43 correspond to the desired type of weft yarn 4.

Fig. 3 illustrates an example of display on the display portion 43. In Fig. 3, the waveform of the yarn signal S1 is displayed in the upper half of the display portion 43 together with the threshold level L1, whereas the waveform of the yarn signal S4 is displayed in the lower half together with the threshold level L2. Moreover, the bottommost section of the display portion 43 displays the detection period T1 of the first weft-sensor unit 21 and a detection period T2 of the second weft-sensor unit 22. The waveforms, the threshold levels, and the detection periods are all displayed along a time axis on the same screen. An operator can visually check the magnitude relationships between the waveforms of the yarn signals S1 and S4 and the threshold levels L1 and L2 on the setting device 20. Accordingly, the threshold levels can be set in a highly accurate manner while judging from the current situation. This contributes to an improvement in efficiency for the operational control of the loom.

Alternatively, the function of the setting device 20 for a loom according to the present invention or the signalprocessing functions of the first weft-sensor unit 21 and second weft-sensor unit 22 may be performed by using a program in a computer. This means that the memory unit 30, the loom controller 40, the setting-display unit 41, the first weft-sensor unit 21, and the second weft-sensor unit 22 included in the setting device 20 are replaceable with input means, output means, memory means, and calculating means (controlling means) included in a common computer.

Furthermore, the yarn signals S1 and S4 are not limited to be output from sensors for weft yarns (ex. weft-sensor unit, cut-yarn sensor), but may alternatively be output from sensors for warp yarns 13 (ex. dropper). Furthermore, it is also possible to read and display a waveform corresponding to an error signal, or read and display a waveform corresponding to a change in condition of the operation of the loom (ex. activation point, change in speed). Furthermore, in a multiple-color weft-insertion loom, the yarn signals corresponding to weft yarns of the selected color types may be selectively displayed.

The present invention is not limited to air jet looms, and may be applied to other fluidic-jet-type looms, such as water jet looms, that are capable of detecting the time in which an inserted weft yarn reaches a predetermined position.

Claims

A setting device (20) for a loom, which compares a yarn signal with a predetermined threshold level and generates an error signal based on the comparison result, the error signal being used for stopping the loom, the setting device (20) being characterized in comprising:

error-detecting means (21, 22) for comparing the yarn signal with the threshold level and generating the error signal based on the comparison result;

a loom controller (40) for stopping the loom in response to the error signal;

a setting-display unit (41) including an input portion (44) and a display portion (43) and connected with the error-detecting means (21, 22) and the loom controller (40), the setting-display unit (41) receiving setting data including the threshold level via the input portion (44), the setting-display unit (41) displaying data from the loom controller (40) on the display portion (43); and

a memory unit (30) connected with the setting-display unit (41) and provided for storing the yarn signal,

wherein the setting-display unit (41) reads a waveform of the yarn signal stored in the memory unit (30) and displays the waveform of the yarn signal and the threshold level on the display portion (43) in an overlapping manner.
The setting device (20) according to Claim 1, characterized in that the waveform of the yarn signal stored in the memory unit (30) corresponds to at least one pick of yarn.
The setting device (20) according to one of Claims 1 and 2, characterized in that, when the loom is a multiple-color weft-insertion type, the memory unit (30) stores the waveform of the yarn signal and a weft-selection condition, and
wherein the setting-display unit (41) displays the waveform of the yarn signal and the threshold level corresponding to an input type of weft yarn.
The setting device (20) according to any one of Claims 1 to 3, characterized in that the error-detecting means comprises two weft-sensor units (21, 22) disposed distant from each other along a weft-traveling path, each weft-sensor unit having a detection region on the weft-traveling path, and
wherein the yarn signal comprises at least one of yarn signals (S1, S4) output from the respective weft-sensor units (21, 22).
The setting device (20) according to any one of Claims 1 to 4, characterized in that the setting-display unit (41) displays the waveform of the yarn signal and the threshold level corresponding to one of cycles of weft insertion in which the error signal is generated.