JP2007146336A - Knitting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent failure from secondarily increasing and specify the source of failure when load or control element of a knitting machine is broken down. <P>SOLUTION: In a knitting machine in which pulse driving is carried out by connecting FET122 to a coil 8 of actuator of the knitting machine, a resistance R2 for detecting electric current is provided and peak value and average value of the current waveform are monitored by comparators 32 and 34 and whether the current waveform is lower than monitoring level of breaking of wire or not is monitored by a comparator 36. The waveforms of clock signal, data signal and load pulse of FPGA4 for control are further monitored by an output pin of FPGA4. When any abnormality is detected, the cause is recorded and displayed and knitting action of the knitting machine is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a knitting machine such as a flat knitting machine, a circular knitting machine, a warp knitting machine, a sock or a glove knitting machine, and more particularly to detection of an abnormality between a pulse operation load and a control element.

  In a knitting machine such as a flat knitting machine, a circular knitting machine, a warp knitting machine, a sock or glove knitting machine, a selection actuator such as a needle selection actuator, a transfer jack or a loop presser is used. These actuators are provided with electromagnets, and the coils are pulse-controlled through control elements. The needle selection actuator and the selection actuator are collectively referred to as a selection actuator. Furthermore, failure and abnormality are synonymous. In the knitting machine, in addition to the selected actuator, a keep solenoid or the like for controlling entrainment of the yarn carrier is used, and similarly, pulse control is performed via the control element.

  When a load such as a selected actuator is short-circuited due to a failure, an overcurrent flows to the control element side, and the control element also secondarily fails. Further, when the control element is short-circuited due to a failure, the load side also secondarily fails due to an overcurrent. For this reason, after the abnormality has expanded secondarily and the load and the control element have become abnormal, it is difficult to identify which caused the failure.

An object of the present invention is to prevent a failure from being secondarily expanded when a load or a control element of a knitting machine fails, and to identify the cause of the failure.
A secondary problem of the present invention is to detect an abnormality of a control IC that controls a control element, a short circuit of a pin, and the like.
A secondary problem of the present invention is that when a load or a control element breaks down, it is possible to reliably prevent the failure from being secondaryly expanded and to make it easy for an operator to confirm the cause of the failure. There is.

  According to the present invention, in a knitting machine that is connected to a control element and detects an abnormality of a load that operates in a pulse manner, the peak value of a current flowing through the load is monitored, and the peak value exceeds a first predetermined value. A short-circuit detecting means for detecting a short-circuit of the load and an average value for monitoring an average value of the current flowing through the load and detecting an abnormality of the control element when the average value exceeds a second predetermined value A value detection means and a stop means for stopping the operation of the load when a short circuit of the load or an abnormality of the control element is detected are provided.

  Preferably, a means for monitoring a potential waveform on the output pin side of the control IC for controlling the control element is further provided to detect abnormality of the control IC.

  Preferably, the stopping means is configured to shut off the power supply of the load when an abnormality is detected, and further provided with means for outputting the cause of the abnormality when the abnormality is detected.

  Preferably, the load is an actuator, and the control element performs chopper control of the load.

  According to the present invention, it is possible to identify whether the abnormality has started from the load side or from the control element side, and when the abnormality occurs, the load is stopped by the stop means to prevent the abnormality from being secondarily enlarged. Since secondary expansion of the abnormality is prevented, the cause of the abnormality can be specified at the load side or the control element side during maintenance.

  When the potential waveform on the output pin side of the control IC for controlling the control element is monitored, it is possible to detect an abnormality inside the IC and a short circuit of the output pin from whether or not the waveform such as the pulse width of the output signal is normal.

  If the load power supply is shut off when an abnormality is detected, the abnormality can be prevented from expanding more reliably. In addition, when an abnormality is detected, if the cause of the abnormality is output to a monitor, a log file, or a LAN connected to the knitting machine, the operator can easily know the cause of the abnormality.

  It is important to use an electromagnet or solenoid coil as the load. If the coil load is short-circuited, the control element can easily fail. Even if the control element is short-circuited, the coil designed for pulse operation is easily short-circuited. Especially when the load is chopper controlled by pulses, there are multiple pulses to turn on the load, so the control element is more prone to failure than the keep solenoid driven by a single pulse, and the peak value and average value of the load current are detected separately. Is easy.

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  1 to 6 show an embodiment and its modifications. In each figure, reference numeral 2 denotes a CPU, which is provided in a controller of a knitting machine such as a flat knitting machine, a circular knitting machine or a warp knitting machine, and controls the entire knitting machine. 4 is an FPGA (Field Programmable Gate Array), and 6 is a PLD (Programmable Logic Device). Reference numeral 8 denotes a coil of a selection actuator. Here, a coil of an actuator for selecting a movable member such as a needle of a knitting machine, a transfer jack, or a loop presser, specifically, a coil of an electromagnet for selection thereof. Reference numerals 10 and 12 denote FETs, which may be other MOS transistor switches, bipolar transistor switches, or relays. D1 is a diode, R1 is a resistor, and is used to consume power of the coil 8 when the FET 10 is turned off.

  The CPU 2 is provided with a failure processing unit 14, a display unit 16 such as a liquid crystal touch panel, and a log file 18. When a failure occurs, the occurrence and cause of the failure are displayed on the display unit 16, and the failure occurs in the log file 18. The data for identifying the coil, the cause of the failure (error code, coil short-circuit, FET short-circuit failure, disconnection, type of signal that caused an abnormality such as FPGA) and the date and time of occurrence of the failure are recorded. The CPU 2 and the FPGA 4 are connected by a bus 20 such as a PCI, 22 is an input interface, 24 is a control signal generator in the FPGA, and generates control signals such as a clock signal, a data signal, and a load pulse signal. The load pulse check unit 26, the data signal check unit 28, and the clock signal check unit 30 are connected to the pins to check the load pulse signal, the data signal, and the clock signal. An abnormality detection signal generated in the FPGA 4 is called e4, and types such as a clock signal abnormality, a data signal abnormality, and a load pulse abnormality are described in the abnormality detection signal e4.

  R2 is a resistance for current detection, and has the meaning of limiting the overcurrent when the coil 8 is short-circuited or when the FET 12 is short-circuited due to a failure and delaying the expansion of the failure. The current flowing through the resistor R2 is i. To do. R3 to R5 are resistors, and C1 to C3 are capacitors. The resistor R3 and the capacitor C1, the resistor R4 and the capacitor C2, the resistor R5 and the capacitor C3 constitute an integrating circuit, and 32 to 36 are comparators. The reason why the integrating circuits (R3, C1) and (R5, C3) are used here is to avoid an inrush current when the FET 12 is turned on, which becomes a noise. The time constant of the integrating circuit for monitoring the peak current constituted by the resistor R3 and the capacitor C1 is made shorter than the time constant of the integrating circuit for monitoring the average current constituted by the resistor R4 and the capacitor C2. The output voltage of the capacitor C1 is a peak current monitoring signal v1, which is a voltage corresponding to the peak value of the current i. The output voltage of the capacitor C2 is an average current monitoring signal v2, which is a signal representing the on-duty ratio of the FET 12. The output voltage of the capacitor C3 may be the disconnection monitoring signal v3, and the disconnection monitoring signal v3 may be replaced by the peak current monitoring signal v1 or the average current monitoring signal v2.

  The IC 38 monitors the outputs of the comparators 32 to 36, and ref1 to ref3 are comparison potentials to the comparators 32 to 36. The IC 38 outputs an abnormality detection signal e1 that means a short circuit of the coil 8 when the comparator 32 changes from on to off. The IC 38 also outputs an abnormality detection signal e2 containing the short-circuit failure of the FET 12 as the comparator 34 changes from on to off. Further, when the comparator 36 changes from on to off, an abnormality detection signal e3 containing the disconnection of the coil 8 or the like is output. The power supply Vcc, coil 8, resistor R1, diode D1, FETs 10 and 12 to the ground line are provided in the carriage of the knitting machine (not shown). The parts from CPU2 to PLD6 and the parts from resistors R3 to R5 to IC38 are provided. It is provided on the controller side of the knitting machine. The abnormality detection signals e1 to e3 are fed back to the CPU 2.

  The CPU 2 in FIG. 1 controls various members in addition to the FPGA 4, and the FPGA 4 keeps the yarn carrier entrainment control solenoid (a solenoid operated by a single pulse) through other control ICs in addition to the PLD 6. To control. Further, the PLD 6 is provided for each selection actuator such as a needle selection device of a knitting machine, a transfer jack or a loop presser, and one selection actuator is usually provided with a plurality of electromagnets, for example, the same selection actuator by signals P ′ and P ″. Control other coils. The power source Vcc is a DC power source and can be turned on / off independently for each selected actuator.

  FIG. 2 shows a modified current monitoring IC 40. The signals v1 and v2 are AD converted by the AD converter 42, and the three comparison voltages ref1 to ref3 stored in the comparison voltage storage unit 44 are used to obtain the peak current monitoring signal v1. Compared with the comparison voltage ref1, the average current monitoring signal v2 is compared with the comparison voltage ref2. The signal v2 is also used as a disconnection monitoring signal and is compared with the comparison voltage ref3. In the case of more accurately detecting the presence or absence of disconnection, it can be used that the current i changes in synchronization with the on / off of the FET 12. Therefore, in this case, for example, it is preferable to detect whether or not the signal v2 changes with an amplitude greater than or equal to the comparison voltage ref3 in synchronization with the on / off of the FET 12. When the comparison unit 46 detects a short circuit of the coil 8 of the selected actuator, a failure (short circuit) of the control FET 12, a disconnection of the coil 8, etc. of the selected actuator, the result is output from the output interface 48 to the abnormality detection signals e 1 to e. Output as e3.

  The IC 40 in FIG. 2 can read a signal at a predetermined timing. Therefore, the integration circuit can be made unnecessary by changing the reading timing and reading the voltage of the resistor R2. For example, when a signal P is input from the FPGA 4 or PLD 6 to the IC 40 and a voltage at a timing near the time when the signal P changes from on to off is used as a peak value monitoring signal and a disconnection monitoring signal. Disconnection can be detected with a short circuit of 8 or less than another predetermined value. Further, a signal after a predetermined time has elapsed after being turned off is used as an average value monitoring signal. If this signal further exceeds another predetermined value, a short-circuit failure of the FET 12 is assumed.

  3 to 5 show operation waveforms of the embodiment. 3 shows the control signal En of the FET 10, and when the coil 8 is operated, the control signal En is set to high level to turn on the FET 10. The FET 12 is turned on in a pulse manner by the control signal P, and when the coil 8 is operated once to select a needle or the like, selection is performed by chopper control using a plurality of pulses. The duty ratio of the pulse signal P is changed according to the temperature of the coil 8 or the ambient temperature. When selecting a needle with a two-stage selection actuator, the number of selected needles around the second-stage selection actuator changes. Here, the selected needle is attracted by the permanent magnet in the selected actuator, and the coil in the selected actuator generates a magnetic flux for canceling the attraction by the permanent magnet. Since the magnetic flux from the permanent magnet flows into the selected needle, the value of the coil current required for the second stage selection may vary depending on the number of needles selected in the first stage. Even in such a case, the duty ratio of the signal P is changed. The solid line waveform in 2) of FIG. 3 shows a standard waveform of the signal P, and the chain line waveform shows a waveform when the duty ratio is increased at the time of activation or the like. 3) in FIG. 3 is a standard waveform of the current i flowing through the resistor R2, and an inrush current is generated when the FET 12 is turned on.

  2) of FIG. 4 shows the waveform of the peak current monitoring signal v1, the solid line shows the waveform at normal time, the one-dot chain line shows the waveform at abnormality, and the two-dot chain line shows the comparison voltage ref1. When the coil 8 is short-circuited, for example, when the short-circuit occurs due to welding of the winding in the coil 8 or adhesion of conductive foreign matter, the peak value of the current i increases, and accordingly, one point of 2) in FIG. A signal v1 having a high peak value such as a chain line is generated. Therefore, a short circuit of the coil 8 can be detected by comparing this signal with the comparison voltage ref1.

  When the FET 12 fails and is short-circuited, the average current monitoring signal v2 becomes a substantially constant high value as indicated by the one-dot chain line in 3) of FIG. Therefore, the failure of the FET 12 can be detected by comparing this with the comparison voltage ref2. When the FET 12 fails, the source and the drain are almost short-circuited. Further, when the duty ratio for turning on the FET 12 is increased, the signal v2 changes as indicated by the broken line in 3). However, if the comparison voltage ref2 is selected to an appropriate value, the FET 12 is short-circuited (duty ratio 100%) and For example, it can be detected separately from when the duty ratio is increased. 4) shows the waveform of the disconnection monitoring signal v3, and the comparison voltage ref3 is selected so as to be lower than the minimum value of the signal v3 when no disconnection occurs in the coil 8, the FET 12, or the like. Therefore, when a break occurs around the coil 8 or the FET 12, the signal v3 falls below the comparison voltage ref3, and the break can be detected.

  FIG. 5 shows the detection of an abnormality at the output pin of the FPGA 4, and the circles indicate the rise or fall of the signal to be monitored. The potential waveform of the output pin of the clock signal is monitored to detect whether the clock signal rises or falls within a predetermined time interval τ1. For example, if the time τ1 is longer than ½ period of the clock signal, there should be a rise or fall during this time. When neither rising nor falling edge exists, the clock signal generation unit or the output pin is abnormal. 2) shows the monitoring of the potential waveform of the output pin of the data signal, and detects whether there is a fall within a predetermined time τ2 from the rise of the data signal. In 2), the monitoring target is indicated by a circle for 3 pulses, but actually monitoring is continued for the subsequent pulses. Further, in 2), since it is shown as active high, the falling of the data signal is monitored, but when it is active low, the rising is detected.

  5) shows monitoring of the potential waveform at the output pin of the load pulse signal, and the PLD 6 enables the reading of the data signal by receiving the load pulse signal. While the carriage of the knitting machine is performing knitting, the load pulse signal should rise or fall within a predetermined time τ3. Therefore, the load pulse signal is checked for abnormalities based on the presence or absence of rise or fall.

  Further, when the output pin of the FPGA 4 is short-circuited, the pin potential is fixed to a specific value. Therefore, if the potential waveform of the output pin is monitored, an abnormality can be detected even when the output pin is short-circuited. The potential waveform of the output pin may be monitored with the potential waveform of the pin itself or with the potential waveform of the wiring connected to the pin. The PLD 6 is a simpler IC than the FPGA 4 and the occurrence of abnormality is mostly on the FPGA 4 side. Therefore, the potential waveform of the output pin on the FPGA 4 side is monitored. If an abnormality such as a short circuit occurs in the input pin on the PLD 6 side, it can be detected by an abnormality in the potential waveform of the output pin on the FPGA 4 side.

  FIG. 6 shows a diagnosis algorithm for the actuator of the knitting machine. When the peak current when the FET 12 is on is a predetermined value or more, a short circuit of the coil 8 of the actuator is detected. When the average value of the current flowing through the current monitoring resistor R2 is equal to or greater than a predetermined value, a short circuit failure of the FET 12 is detected. Further, when the minimum value of the voltage v3 is equal to or less than a predetermined value, the disconnection of the coil 8 is detected. In addition, an abnormality of the FPGA 4 is detected by the abnormality detection signal e4.

  For each cause of abnormality, data identifying the actuator and its coil in which the failure occurred, or data identifying the FPGA, and the cause of the abnormality (coil short circuit, FET failure, disconnection, control element abnormality type) Error code) and the date and time of occurrence of the abnormality are recorded in the log file 18. Further, the CPU 2 or the FPGA 4 or the like cuts off the power source Vcc from the coil 8 and stops the knitting operation in the carriage including the coil 8 in which an abnormality has occurred. When the knitting machine includes a plurality of carriages, the knitting operation is stopped only for the carriage having the coil 8 or the FET 12 in which an abnormality has occurred, and the knitting is continued with another carriage. Further, the monitor 16 displays that a failure has occurred and its cause, and waits for maintenance. When the knitting machine is connected to the LAN, the occurrence of the abnormality and the cause thereof are output to the LAN. The reason why the knitting is stopped due to the occurrence of an abnormality is that, for example, when the coil 8 is short-circuited, the FET 12 fails next due to overcurrent, and when the FET 12 fails, the coil 8 is next short-circuited due to overcurrent.

In the embodiment, the following effects can be obtained.
(1) Abnormalities can be detected while identifying the cause of the short circuit of the actuator coil 8, the failure (short circuit) of the control switch (FET 12), the disconnection, and the failure of the control IC 4.
(2) By using the peak current monitoring signal v1, a short circuit of the coil 8 of the actuator can be reliably detected.
(3) By using the average current monitoring signal v2, a failure of a switch such as the FET 12 can be reliably detected. Note that a failure of a switch such as the FET 12 cannot be detected with the peak current monitoring signal v1, and if a short circuit of the coil 8 is detected with the average current monitoring signal v2, it is difficult to distinguish from a case where the duty ratio for turning on the coil 8 is increased.
(4) Disconnection of the coil 8 or disconnection around the FET 12 can be detected.
(5) It is possible to monitor abnormalities such as internal abnormalities of the control IC 4 and output pin shorts.
(6) The resistance R2 can limit the short-circuit current and delay the secondary expansion of the abnormality between the coil 8 and the FET 12.

Block diagram of the diagnosis device for the actuator of the knitting machine of the embodiment Block diagram of a current monitoring IC of a modified example In the waveform diagram of the diagnostic apparatus of FIG. 1, 1) shows the waveform of the control signal En of the regenerative FET, 2) shows the waveform of the control signal P of the selected actuator, and 3) shows the waveform of the current i to the current detection resistor R2. Indicates. 1) shows the waveform of the current i to the current detection resistor R2, 2) shows the peak current monitoring signal v1, 3) shows the average current monitoring signal v2, and 4) shows disconnection. The waveforms of the monitoring signal v3 are shown respectively. In the waveform diagram of the self-diagnosis signal of the control IC, 1) shows monitoring of the clock signal, 2) shows monitoring of the data signal, and 3) shows monitoring of the load pulse signal. In the control flowchart of an Example, the process until it detects an abnormality of an actuator, stops a knitting machine, and displays the cause of abnormality is shown.

Explanation of symbols

2 CPU
4 FPGA
6 PLD
8 Selected actuator coil 10, 12 FET
14 Fault processing unit 16 Display unit 18 Log file 20 Bus 22 Input interface 24 Control signal generation unit 26 Load pulse check unit 28 Data signal check unit 30 Clock signal check unit 32-36 Comparator 38, 40 IC
42 AD Converter 44 Comparison Voltage Storage Unit 46 Comparison Unit 48 Output Interface D1 Diodes R1 to R5 Resistors C1 to C3 Capacitor Vcc Power Supply P Control Signal v1 Peak Current Monitoring Signal
v2 Average current monitoring signal v3 Disconnection monitoring signal
e1 to e4 error detection signal

Claims (4)

In a knitting machine that is connected to a control element and detects a load abnormality that operates in a pulse manner,
Short-circuit detection means for monitoring a peak value of the current flowing through the load and detecting a short-circuit of the load when the peak value exceeds a first predetermined value;
An average value detecting means for monitoring an average value of the current flowing through the load and detecting an abnormality of the control element when the average value exceeds a second predetermined value;
A knitting machine, comprising: a stopping means for stopping the operation of the load when a short circuit of the load or an abnormality of the control element is detected. 2. The knitting machine according to claim 1, further comprising means for monitoring a potential waveform on the output pin side of the control IC for controlling the control element so as to detect an abnormality of the control IC. . The knitting machine according to claim 1 or 2, wherein the stopping means is configured to shut off a load power supply when an abnormality is detected, and further provided with means for outputting the cause of the abnormality when the abnormality is detected. The knitting machine according to any one of claims 1 to 3, wherein the load is an actuator and the control element performs chopper control of the load.

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