JP5040697B2 - Machine Tools - Google Patents

Description

  The present invention relates to a machine tool, and more particularly, to a machine tool that can early identify a controlled device in which a short circuit or a ground fault has occurred.

  Conventionally, a large number of devices such as relays, electromagnetic valves, motors, limit switches (hereinafter collectively referred to as “controlled devices”) are connected to machine tools. And the drive control and monitoring control of a controlled apparatus are performed by performing control which switches the voltage applied with respect to these controlled apparatuses as needed by a machine tool. Here, if a short circuit or ground fault occurs in the controlled device itself or in the connecting line that connects the machine tool and the controlled device, the overcurrent flows through the machine tool and the controlled device and breaks. There is a risk that. Therefore, when a short circuit and a ground fault occur, it is necessary to immediately stop the voltage application, identify the location where the short circuit and the ground fault occur, take measures, and restore control.

However, there are often very many controlled devices connected to the machine tool. In this case, it takes a lot of time to identify the location where the short circuit and the ground fault occur and take measures to make it recoverable. Under such circumstances, when a short circuit and a ground fault occur, turn ON in order for all combinations of the ON state of multiple general-purpose output elements, detect the voltage in each case, and determine the location of the occurrence of the short circuit and the ground fault By specifying, the control apparatus which enabled it to respond rapidly with respect to generation | occurrence | production of a short circuit and a ground fault is proposed (for example, refer patent document 1).
JP-A-53-386

  However, in the control device described in Patent Document 1, it is necessary to sequentially turn on all combinations of the ON states of a plurality of general-purpose output terminals. Therefore, when there are a large number of general-purpose output terminals, the number of combinations of the ON states becomes very large, and there is a problem that it takes a long time to identify the location where a short circuit and a ground fault occur. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a machine tool capable of quickly identifying the occurrence of a short circuit and a ground fault.

In order to solve the above-described problem, a machine tool according to a first aspect of the present invention is a machine tool that controls a controlled device by switching applied voltages to a plurality of controlled devices to be connected. A power source for applying a voltage to the controlled device, and a continuity switching means for switching an applied voltage to each controlled device by switching conduction / non-conduction of the electric circuit between the power source and each controlled device; Device control means for controlling the conduction switching means, sequentially switching the applied voltage to each controlled device to control each controlled device, and storage means for storing a history of switching of the applied voltage by the device control means; A detection means for detecting that a short circuit or a ground fault has occurred, a switch for opening and closing an electric circuit between the power source and the controlled device, and a case where the detection means detects a short circuit or a ground fault. An opening means for controlling the switch to open an electric circuit between the power source and the controlled device and interrupting the energization; and an energization between the power source and the controlled device is interrupted by the opening means In this state, notification means for notifying history information, which is history information stored in the storage means, and the detection means detect a short circuit or a ground fault, and the opening means controls the switch. Then, in a state where the energization to the controlled device is cut off, the conduction switching means is controlled to make the electric circuit between the power source and all the controlled devices non-conductive, and the switch is controlled again. Closing means for closing an electric circuit between the power source and the controlled device and resuming energization, and in the state where energization between the power source and the controlled device is resumed by the closing means, the storage means History stored in Based on the information, device history control means for controlling the conduction switching means that has switched the electrical circuit to the conduction state at the time when the detection means detects a short circuit or a ground fault, and the device history control means, While the applied voltage is being switched, the detection unit detects the short circuit or the ground fault again, and the detection unit detects the short circuit or ground fault when the energization between the power source and the controlled device is interrupted by the open unit. Specifying means for specifying the controlled device that is electrically connected to the power source when a short circuit or a ground fault is detected by the means, and the notification means is the target specified by the specifying means. The control device is notified to the outside .

Further, the machine tool of the invention according to claim 2, in addition to the configuration of the invention according to claim 1, wherein the detecting means detects that the voltage of the power supply is equal to or less than the predetermined range, the power source and the A short-circuit detection means for determining that a short-circuit that is electrically connected to a signal ground that is a reference potential for a power source has occurred, and a current flows between the frame ground of the machine tool connected to the ground and the signal ground, thereby Ground fault detection means for detecting that a potential difference has occurred between the frame ground and the signal ground, and determining that a ground fault has occurred between the power source and the frame ground.

Further, in the machine tool of the invention according to claim 3 , in addition to the configuration of the invention of claim 2 , the controlled device is a switch for switching between conduction / non-conduction between the first contact and the second contact. In the case where the switch is provided with a first connection line connecting the conduction switching means and the first contact, and a second connection line connected to the second contact of the switch, The machine tool includes switch voltage detection means for detecting the voltage of the second connection line.

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, the machine tool in the state where the first contact and the second contact of the switch are non-conductive. While the voltage applied to the switch is sequentially switched by the history control means, the ground fault detection means detects the occurrence of a ground fault, and simultaneously with the detection by the ground fault detection means, A first connection line ground fault judgment means for judging that a ground fault has occurred in the first connection line when the switch voltage detection means does not detect a voltage of a predetermined value or more; and the first connection line First connection line notification means for notifying the first connection line determined by the ground fault determination means to the outside.

Further, in the machine tool of the invention according to claim 5 , in addition to the configuration of the invention of claim 3 or 4 , in a state where the first contact and the second contact of the switch are non-conductive, While the voltage applied to the switch is being sequentially switched by the device history control means, the ground fault detection means detects the occurrence of a ground fault simultaneously with the detection by the ground fault detection means. A first second connection line that determines that a ground fault has occurred simultaneously in both the first connection line and the second connection line when the switch voltage detection means detects a voltage greater than or equal to a predetermined value. Ground fault determination means, and first second connection line notification means for notifying the first connection line and the second connection line determined by the first second connection line ground fault determination means to the outside.

In addition to the configuration of the invention according to any one of claims 3 to 5 , the machine tool of the invention according to claim 6 is in a state in which the first contact and the second contact of the switch are electrically connected. When the ground fault detecting means detects the occurrence of a ground fault while the applied voltage to the switch is being switched in order by the device history control means, a ground fault occurs in the second connection line. 2nd connection line ground fault judgment means which judges that it has generate | occur | produced, and 2nd connection line notification means which notifies the said 2nd connection line judged by said 2nd connection line ground fault judgment means to the exterior .

In the machine tool according to the first aspect of the present invention, when a short circuit and a ground fault are detected, the switch is controlled to open an electric path between the power source and the controlled device, thereby interrupting energization. Then, the stored history information is notified to the outside. Therefore, when a short circuit or a ground fault occurs in the controlled device connected to the machine tool, the voltage application to the controlled device is immediately stopped, thereby causing an overcurrent flow to the machine tool and the controlled device. It becomes possible to prevent damage. In addition, by displaying the history information, the administrator can quickly identify the controlled device that is the cause of the occurrence of a short circuit or ground fault, and take countermeasures. Can be recovered early. In addition, after detecting a short circuit and ground fault, opening the electrical path to the controlled device and shutting off the power, the electrical circuit is in a conductive state when the detection means detects a short circuit or ground fault based on the stored history information The applied voltage is switched by controlling the conduction switching means that has been switched to. And when a short circuit or a ground fault is detected again, the controlled apparatus with which the electric circuit between the power supplies is conducted at the time when a short circuit or a ground fault is detected is specified. Then, the specified controlled device is notified to the outside. Therefore, by controlling the controlled device again according to the history information, it becomes possible to identify the controlled device in which a short circuit or a ground fault has occurred, and to notify the administrator of the identified controlled device. This facilitates the work of investigating the cause of the occurrence of a short circuit or ground fault by the administrator. Then, when the manager eliminates the cause of the occurrence of the short circuit or the ground fault, the current supply to the controlled device can be restarted at an early stage, and the drive control of the controlled device by the machine tool can be restored.

Further, since the machine tool of the invention according to claim 2 includes the short-circuit detection means and the ground fault detection means, in addition to the effect of the invention according to claim 1 , a short-circuit has occurred, or the ground It is possible to determine whether or not an entanglement has occurred. This makes it possible for the manager to narrow down the locations where short circuits and ground faults occur. Then, by eliminating the cause of the occurrence of the short circuit or the ground fault, the administrator can restart the current supply to the controlled device at an early stage and restore the drive control of the controlled device by the machine tool.

Further, in the machine tool of the invention according to claim 3 , in addition to the effect of the invention of claim 2, when the controlled device is a switch, ON / OFF of the switch can be detected.

Moreover, in the machine tool of the invention according to claim 4 , in addition to the effect of the invention according to claim 3 , the switch in which the ground fault has occurred is specified, and the ground fault of the connection lines connected to the switch is specified. It is possible to identify the connection line in which the occurrence is the first connection line and notify the administrator. This makes it possible for the administrator to identify the location of the ground fault at an early stage, eliminate the cause early, restart the current supply to the switch, and restore the switch monitoring control by the machine tool. Is possible.

Further, in the machine tool of the invention according to claim 5 , in addition to the effect of the invention of claim 3 or 4 , the switch in which the ground fault has occurred is specified, and among the connection lines connected to the switch It is possible to identify and notify the administrator that the connection line where the ground fault has occurred is both the first connection line and the second connection line. This makes it possible for the administrator to identify the location of the ground fault at an early stage, eliminate the cause early, restart the current supply to the switch, and restore the switch monitoring control by the machine tool. Is possible.

Moreover, in the machine tool of the invention according to claim 6 , in addition to the effect of the invention according to any one of claims 3 to 5 , the switch in which the ground fault has occurred is specified and the connection connected to the switch It becomes possible to identify and notify the administrator that the connection line in which the ground fault has occurred is the second connection line. This makes it possible for the administrator to identify the location of the ground fault at an early stage, eliminate the cause early, restart the current supply to the switch, and restore the switch monitoring control by the machine tool. Is possible.

  Embodiments of the present invention will be described below with reference to the drawings. First, the hardware configuration of the machine tool 1 will be described with reference to FIG. The machine tool 1 according to the present embodiment is a machine that can perform drive control by switching voltage application to a large number of connected controlled devices. FIG. 1 is a block diagram illustrating an example of a hardware configuration of a machine tool 1 and controlled devices connected to the machine tool 1. In this embodiment, as will be described later, there are a total of four relays (first relay 51, second relay 52, third relay 53, fourth relay 54, hereinafter collectively referred to as "relay 65" as controlled devices. And a total of two limit switches (first switch 55, second switch 56, hereinafter collectively referred to as "switch 66") are connected to the machine tool 1 (hereinafter referred to as connected relays). 65 and the switch 66 are collectively referred to as “controlled device 67”). And the case where the operation of the controlled device 67 is controlled by switching the voltage applied to the controlled device 67 by the machine tool 1 is assumed. Note that the types and quantities of the controlled devices 67 connected to the machine tool 1 of the present invention are not limited to the present embodiment.

  As shown in FIG. 1, the machine tool 1 provides an operator with an operation panel 61 including switches and buttons for operating the machine itself, and an operation state of the machine tool 1 and a place that causes an abnormality. And a display 62 for notification. The machine tool 1 is connected to the ground at the ground portion 4 of the housing frame 3 (hereinafter, the potential of the housing frame 3 is referred to as “frame ground” and “FG”). Built in. The signal ground (hereinafter referred to as “SG”) of the control board 2 and the CPU 10 are connected. The control board 2 includes a CPU 10 that controls the entire machine tool 1, and the aforementioned operation panel 61 and display device 62 are connected to each other. Then, the CPU 10 receives an electrical signal generated when the operation panel 61 is operated by the operator, so that the operation content can be grasped. Further, the image displayed on the display device 62 can be controlled by transmitting a control signal from the CPU 10 to the display device 62.

  The control board 2 includes a ROM 11 that is a non-volatile storage element that stores a program necessary for the CPU 10 to operate, and a volatile storage element that temporarily stores data required when the CPU 10 performs arithmetic processing. The RAM 12 is provided. The ROM 11 and RAM 12 are connected to the CPU 10 via a bus. Further, the control board 2 includes a power source 15 for applying a voltage to the controlled device 67 (relay 65 and switch 66) to be connected. (Hereinafter simply referred to as “ON”) / non-conduction (hereinafter simply referred to as “OFF”) or the bias voltage of the switch 66 can be applied.

  In addition, an electromagnetic switch 16 and a first FET 21 to a sixth FET 26 (hereinafter collectively referred to as “FET 68”) are inserted in the electric path between the power supply 15 and the controlled device 67, respectively. Among these, the electromagnetic switch 16 is connected to the CPU 10 so that the CPU 10 can control the opening / closing of the contacts. The electromagnetic switch 16 is opened between the power supply 15 and the FET 68 so that the contact is opened when the CPU 10 detects an overcurrent flow, and the machine tool 1 and the controlled device 67 can be prevented from malfunctioning and accidents. It is inserted in series in the electric circuit.

  Further, the FET 68 is inserted in series in the electric circuit between the electromagnetic switch 16 and the controlled device 67 in order to switch the conduction state from the power source 15 to the controlled device 67 under the control of the CPU 10. The source signal of the FET 68 is connected to the controlled device 67, the drain signal is connected to the electromagnetic switch 16, and the gate signal is connected to the output port of the CPU 10. Therefore, by controlling the voltage level of the output port of the CPU 10, the conduction (hereinafter simply referred to as “ON”) / non-conduction (hereinafter simply referred to as “OFF”) between the drain and source of the FET 68 can be switched. It is possible.

  The FET 68 is connected to a relay 65 (first relay 51 to fourth relay 54) and a switch 66 (first switch, second switch). Among these, the source signal of the first FET 21 and the coil of the first relay 51 are connected by the connection line 31, the source signal of the second FET 22 and the coil of the second relay 52 are connected by the connection line 32, and the third The source signal of the FET 23 and the coil of the third relay 53 are connected by a connection line 33, and the source signal of the fourth FET 24 and the coil of the fourth relay 54 are connected by a connection line 34. The side of each coil that is not connected to the FET is connected to SG, which is the reference potential of the power supply 15. As a result, the CPU 10 can control the current to the coil by switching ON / OFF between the drain and source of the first FET 21 to the fourth FET 24, and can switch ON / OFF of the relay 65.

  Further, the source signal of the fifth FET 25 and one contact 55 a of the first switch 55 are connected by a connection line 35, and the other contact 55 b of the first switch 55 and the input port of the buffer 27 provided on the control board 2. Are connected by a connection line 37. The source signal of the sixth FET 26 and one contact 56 a of the second switch 56 are connected by a connection line 36, and the other contact 56 b of the second switch 56 and the input port of the buffer 28 provided on the control board 2. Are connected by a connection line 38. Further, the output ports of the buffers 27 and 28 are connected to the input port of the CPU 10. As a result, the CPU 10 can apply the bias voltage of the switches 55 and 56 by switching ON / OFF between the drain and source of the fifth FET 25 or the sixth FET 26, and from the input signals from the buffers 26 and 27. It is possible to determine whether the contacts of the switches 55 and 56 are conductive (hereinafter simply referred to as “ON”) / non-conductive (hereinafter simply referred to as “OFF”).

  The control board 2 is provided with a short circuit detection circuit 13 and a ground fault detection circuit 14. The short circuit detection circuit 13 is a circuit for detecting the occurrence of a short circuit between the power supply 15 and SG (referred to as “short circuit”) (details will be described in detail in FIG. 2 (described later)). The ground fault detection circuit 14 is a circuit for detecting the occurrence of a short circuit between the power supply 15 and the FG (referred to as “ground fault”) (details are described in detail in FIG. 3 (described later)). To do.) The short circuit detection circuit 13 and the ground fault detection circuit 14 are connected to the CPU 10, and when it is detected that a short circuit and a ground fault have occurred, the CPU 10 can be notified by an electrical signal. . As a result, the CPU 10 controls the electromagnetic switch 16 to open the contact when a short circuit and a ground fault occur, opens the circuit from the power source 15, and prevents overcurrent caused by the short circuit and the ground fault. It is possible to prevent the occurrence of a failure by interrupting energization.

  In the present embodiment, as a cause of occurrence of a short circuit and a ground fault, there is a short circuit between the wiring on the control board 2 and SG and FG, and connection lines 31 to 38 that connect the machine tool 1 and the controlled device 67. A short circuit between the connection lines 31 to 38 and the FG, a short circuit between the internal wiring of the controlled device 67 and SG, FG, etc., which are generated by being sandwiched between the housing frame 3 and the lid (not shown). The details will be described later.

  Next, an outline of the circuit configuration of the short circuit detection circuit 13 and the ground fault detection circuit 14 will be described with reference to FIGS. FIG. 2 is a schematic diagram of a circuit configuration of the short circuit detection circuit 13, and FIG. 3 is a schematic diagram of a circuit configuration of the ground fault detection circuit 14.

  First, an outline of the circuit configuration of the short circuit detection circuit 13 will be described with reference to FIG. As shown in FIG. 2, the short circuit detection circuit 13 detects an electric potential difference between the + side input port and the − side input port and notifies the CPU 10 that a short circuit has occurred, and a power source 15. And resistors 71 and 72 that divide the voltage of the power source 15 and a reference power source 74 for determining the voltage divided by the resistors 71 and 72.

  Among these, the power source 15 is connected to one end side of the resistor 71, the other end side of the resistor 71 is connected to one end side of the resistor 72, and the other end side of the resistor 72 is connected to SG. Further, the negative side input port of the OP amplifier 73 is connected to the connection portion 76 between the resistors 71 and 72, and the positive side input port of the OP amplifier 73 is connected to the positive side of the reference power source 74. The-side is connected to SG. The output port of the OP amplifier 73 is connected to the input port of the CPU 10 (see FIG. 1). The voltage of the reference power source 74 is set in advance so as to be equal to or lower than the voltage generated at the connection portion 76 between the resistor 71 and the resistor 72 in the above circuit configuration.

  In the short circuit detection circuit 13 shown in FIG. 2, in a normal state where the power supply 15 and SG are not short-circuited, the voltage at the − side input port of the OP amplifier 73 is higher than the voltage at the + side input port. Become. Therefore, the voltage output from the output port of the OP amplifier 73 is 0 V (hereinafter referred to as “Low level”). On the other hand, in a state where a short circuit in which the power supply 15 and SG are short-circuited occurs, the voltage at the − side input port of the OP amplifier 73 is 0V, but the voltage at the + side input port is the voltage of the reference power supply 74. A voltage level having a predetermined + polarity (hereinafter referred to as “Hi level”) is output from the output port of the OP amplifier 73. The voltage output from the OP amplifier 73 is detected by the CPU 10.

  As described above, the short circuit detection circuit 13 is configured to be able to displace the output voltage when a short circuit occurs. Then, the signal from the short circuit detection circuit 13 is constantly monitored by the CPU 10, and it is determined that the short circuit has not occurred in the low level state, and it is determined that the short circuit has occurred in the high level state. Is done.

  Next, an outline of the circuit configuration of the ground fault detection circuit 14 will be described with reference to FIG. As shown in FIG. 3, the ground fault detection circuit 14 detects the current flow and pulls up the photocoupler 85 for notifying the CPU 10 that a ground fault has occurred and the output signal of the photocoupler. Power source 15 and resistor 86, and resistors 81 and 82 connected in series between FG and SG.

  Among these, one end side of the resistor 81 is connected to the FG, the other end side of the resistor 81 is connected to one end side of the resistor 82, and the other end side of the resistor 82 is connected to SG. The anode port of the diode constituting the photocoupler 85 is connected to the connection portion 87 between the resistor 81 and the resistor 82, and the cathode port of the diode constituting the photocoupler 85 is connected to SG. Further, the power supply 15 and one end side of the resistor 86 are connected, the other end side of the resistor 86 and the collector port of the transistor constituting the photocoupler 85 are connected, and connected to the input port of the CPU 10 (see FIG. 1). . The emitter port of the transistor constituting the photocoupler 85 is connected to SG.

  In the ground fault detection circuit 14 shown in FIG. 3, in a normal state where the power supply 15 and the FG are not short-circuited, the FG and SG are connected at only one point via the resistor 81 and the resistor 82, and the potential difference between the two. Does not occur. Therefore, since no current flows through the resistor 82, no voltage is generated between the anode port and the cathode port of the diode constituting the photocoupler 85, and the collector port of the transistor constituting the photocoupler 85 is in a high impedance state. Become. Since the collector port is pulled up by the power supply 15, the collector port has a predetermined + polarity voltage level (hereinafter referred to as “Hi level”). On the other hand, in a state where a ground fault has occurred where the power supply 15 and FG are short-circuited, a potential difference is generated between FG and SG, and a current flows through the resistor 82. Thus, a potential difference is generated between the anode port and the cathode port of the diode constituting the photocoupler 85, the transistor collector port and the emitter port of the transistor are brought into conduction, and the collector port is referred to as 0 V (hereinafter referred to as “Low level”). ) Then, the voltage of the collector port is detected by the CPU 10.

  As described above, the ground fault detection circuit 14 has a configuration capable of displacing the voltage at the collector port of the transistor constituting the photocoupler 85 when a ground fault occurs. The signal from the ground fault detection circuit 14 is constantly monitored by the CPU 10, and it is determined that no ground fault has occurred in the Hi level, and a ground fault occurs when the Low level is reached. It is judged that

  Next, an outline of the storage area of the RAM 12 included in the control board 2 will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic diagram showing an overview of the storage area of the RAM 12, and FIG. 5 is a schematic diagram showing an overview of the history information storage area 302 of the RAM 12. Note that the storage area of the ROM 11 provided in the control board 2 is omitted.

  First, the outline of the storage area of the RAM 12 will be described with reference to FIG. The RAM 12 is provided with a control content information storage area 301, a history information storage area 302, a connected controlled device information storage area 303, and other storage areas.

  Among these, in the control content information storage area 301, the control content (controlled device to be controlled) of the controlled device 67 (see FIG. 1) operated by the operator via the operation panel 61 (see FIG. 1). When a number, ON / OFF, etc.) are input, this input information is stored as control content information. Alternatively, when the controlled device 67 (see FIG. 1) is controlled in the process in which the CPU 10 controls the machine tool 1 based on a machining program stored in an external storage device (not shown), the above-described control content is controlled as control content information. It is stored in the content information storage area 301. Further, when the controlled devices 67 are actually controlled, the controlled devices 67 are driven by controlling the application of voltage to the connected controlled devices 67 based on the stored control content information. I let you.

  In the history information storage area 302, the type and ON / OFF information of the FET 68 (see FIG. 1) that has been controlled to switch on / off of voltage application, and the information on the time at which the control was performed are recorded as history information. Remembered. And the recovery process (refer FIG. 7, FIG. 8) after a short circuit and the occurrence of a ground fault is performed by referring to the stored history information (details will be described later).

  In the connected controlled device information storage area 303, the type of the controlled device 67 connected to the machine tool 1 (see FIG. 1) is stored in association with each connected FET 68 (see FIG. 1). The For example, in the configuration of the controlled device 67 shown in FIG. 1, the first relay 51 is connected to the first FET 21, the second relay 52 is connected to the second FET 22, and the third relay 53 is connected to the third FET 23. Are connected, and the information that the fourth relay 54 is connected to the fourth FET 24 is stored in the connected controlled device information storage area 303, respectively. Further, information indicating that the first switch 55 is connected to the fifth FET 25 and the second switch 56 is connected to the sixth FET 26 is stored in the connected controlled device information storage area 303, respectively. When the voltage application of the controlled device 67 (see FIG. 1) is controlled based on the information stored in the control content information storage area 301, the FET 68 connected to the controlled device 67 to be controlled is controlled. In addition, when a short circuit and a ground fault occur, the controlled device 67 connected to the source signal of the FET 68 is specified (see FIGS. 7 and 8; described later). ).

  Next, an overview of the history information storage area 302 of the RAM 12 will be described with reference to FIG. As shown in FIG. 5, in the history information storage area 302, history information of ON / OFF switching between the drain signals and the source signals of the first FET 21 to the sixth FET 26 is stored together with time information. When new history information is stored, the history information with numbers “1” to “5” in “history order” shown in FIG. 5 is moved down one row at a time to “2” to “6”. , And information on ON / OFF switching between the drain signal to the source signal of the first FET 21 to the sixth FET 26 is stored together with time information in the stage “1”.

  For example, in the example shown in FIG. 5, at the timing of “20: 50: 5” 09, the first FET 21 is “ON”, the second FET 22 is “OFF”, and the third FET 23 is “ON”. This indicates that the fourth FET 24 is “ON”, the fifth FET 25 is “ON”, and the sixth FET 26 is “OFF”. Also, at the timing of “20:48:45”, the first FET 21 is “OFF”, the second FET 22 is “OFF”, the third FET 23 is “OFF”, and the fourth FET 24 is “OFF”. The fifth FET 25 is “ON” and the sixth FET 26 is “OFF”. In addition, at the timing of “20:46:30”, the first FET 21 is “ON”, the second FET 22 is “OFF”, the third FET 23 is “OFF”, and the fourth FET 24 is “ON”. This shows that the fifth FET 25 is “ON” and the sixth FET 26 is “ON”. Further, at the timing of “20:46:30” 01, the first FET 21 is “OFF”, the second FET 22 is “ON”, the third FET 23 is “ON”, and the fourth FET 24 is “OFF”. The fifth FET 25 is “OFF”, and the sixth FET 26 is “OFF”. In addition, at the timing of “20:30:10 seconds 56”, the first FET 21 is “ON”, the second FET 22 is “OFF”, the third FET 23 is “ON”, and the fourth FET 24 is “OFF”. The fifth FET 25 is “OFF”, and the sixth FET 26 is “ON”.

  Next, a flowchart of processing executed by the CPU 10 (see FIG. 1) of the machine tool 1 when a short circuit or ground fault occurs will be described with reference to FIGS. FIG. 6 is a main flowchart of the control process of the controlled device 67 (see FIG. 1) and the recovery process executed when a short circuit and a ground fault occur. FIG. 7 is a flowchart of a recovery process executed when a short circuit or a ground fault occurs. FIG. 8 is a subroutine flowchart of a process for identifying a short-circuit ground fault occurrence site, which is executed when the cause of the occurrence of the short circuit and the ground fault is in the switch 66 (see FIG. 1) and its surroundings. Note that the CPU 10 can perform multitask processing, and the CPU 10 can perform processing for controlling the machine tool 1 based on the above-described processing program separately from the processing shown in FIG. The process of FIG. 6 is executed every predetermined time.

  First, the control process of the controlled device 67 (see FIG. 1) executed by the CPU 10 (see FIG. 1) included in the control board 2 of the machine tool 1 and the recovery process executed when a short circuit and a ground fault occur. The main flowchart will be described with reference to FIG. The CPU 10 controls the application of voltage to the connected controlled device 67 based on the control content information stored in the control content information storage area 301 (see FIG. 5) of the RAM 12, and drives the controlled device 67. Yes.

  As shown in FIG. 6, first, the control content information stored in the control content information storage area 301 (see FIG. 5) of the RAM 12 is read, and the controlled application for switching the voltage application based on the read content. Whether the device 67 (see FIG. 1) is the first relay 51 to the fourth relay 54, the first switch 55, or the second switch 56 (see FIG. 1) is specified. At the same time, referring to the connected controlled device information stored in the connected controlled device information storage area 303 (see FIG. 5) of the RAM 12, the FET 68 to which the specified controlled device 67 is connected (see FIG. 1). Is specified from among the first FET 21 to the sixth FET 26 (see FIG. 1) (S10).

  Next, the control is applied to the specified controlled device 67 to be controlled (any one of the first relay 51 to the fourth relay 54, the first switch 55, and the second switch 56) (see FIG. 1). It is determined whether the control (hereinafter simply referred to as “ON”) or the control to cancel the voltage application state (hereinafter simply referred to as “OFF”) (S11).

  When the control is to turn on the voltage for the controlled device 67 specified as the control target (see FIG. 1) (S11: YES), it is specified as the FET 68 (see FIG. 1) to which the controlled device 67 is connected. In addition, the gate signal of any one of the first FET 21 to the sixth FET 26 (see FIG. 1) is controlled to turn on between the drain signal and the source signal, and the power source 15 (see FIG. 1) The electric circuit between the control device 67 is made conductive, and a voltage is applied to the controlled device 67 (S13). Thus, if the specified controlled device 67 is the relay 65 (see FIG. 1), ON / OFF is switched, and if the controlled device 67 is the switch 66 (see FIG. 1), a bias voltage is applied. Thus, it becomes possible to monitor the ON / OFF of the switch 66.

  Next, the information on whether the identified FET 68 (see FIG. 1) is the first FET 21 to the sixth FET 26 (see FIG. 1) and the voltage ON / OFF information are recorded in the history of the RAM 12 together with the controlled time information. It is stored in the information storage area 302 (see FIG. 5) (S15).

  Next, the drain signal to the source signal of the FET 68 (see FIG. 1) are turned on to make the electric circuit between the power supply 15 and the controlled device 67 (see FIG. 1) conductive, and the voltage applied to the controlled device 67 is turned on. It is determined whether or not a short circuit has occurred at the timing (S17). In the part to which voltage is applied in the controlled device 67, and in the connection lines 31 to 38 (see FIG. 1) connecting the machine tool 1 (see FIG. 1) and the controlled device 67, the part to which the voltage is applied and SG If there is a portion where the two are short-circuited, a short circuit in which an overcurrent flows through the portion at the timing when the applied voltage is turned ON. This short circuit occurrence is detected by the short circuit detection circuit 13, and the displacement of the output voltage is output to the CPU 10 (see FIG. 1), so that it is determined that a short circuit has occurred (S17: YES). If it is determined that a short circuit has occurred, the process then proceeds to a process of opening the electromagnetic switch 16 (see FIG. 1) to cut off the energization of the controlled device 67 and a recovery process (S29 to S37). To do.

  When a short circuit is not detected by the short circuit detection circuit 13 (see FIG. 1) (S17: NO), the drain signal to the source signal of the FET 68 (see FIG. 1) are turned ON to turn on the power source 15 (see FIG. 1). It is determined whether or not a ground fault has occurred at the timing when the electrical path to the controlled device 67 (see FIG. 1) is turned on and the voltage applied to the controlled device 67 is turned on (S19). In the part to which the voltage is applied in the controlled device 67, and in the connection lines 31 to 38 (see FIG. 1) connecting the machine tool 1 (see FIG. 1) and the controlled device 67, the part to which the voltage is applied and the FG If there is a portion in which the short circuit is short-circuited, a ground fault in which an overcurrent flows through the portion at the timing when the applied voltage is turned ON. The occurrence of the ground fault is detected by the ground fault detection circuit 14, and the displacement of the output voltage is output to the CPU 10 (see FIG. 1), so that it is determined that the ground fault has occurred (S19: YES). If it is determined that a ground fault has occurred, the process then opens the electromagnetic switch 16 (see FIG. 1) to cut off the energization of the controlled device 67 and the recovery process (S29 to S37). Will migrate.

  When there is no controlled device 67 (see FIG. 1) that turns on the voltage application state (S11: NO), or the short circuit detection circuit 13 (see FIG. 1) does not detect a short circuit (S17: NO), and the ground fault If the detection circuit 14 (see FIG. 1) does not detect a ground fault (S19: NO), then control is performed based on the control content information read from the control content information storage area 301 (see FIG. 5) of the RAM 12. The control for the controlled device 67 (one of the first relay 51 to the fourth relay 54, the first switch 55, and the second switch 56) identified as the target (see FIG. 1) is a control for turning off the voltage application state. It is specified whether or not there is (S21). When there is no controlled device 67 (see FIG. 1) that turns off the voltage application state (S21: NO), the process proceeds to S10.

  When the control is to turn off the voltage for the controlled device 67 specified as the control target (see FIG. 1) (S21: YES), it is specified as the FET 68 (see FIG. 1) to which the controlled device 67 is connected. For any one of the first FET 21 to the sixth FET 26 (see FIG. 1), the gate signal is controlled so as to turn off between the drain signal and the source signal, and the power source 15 (see FIG. 1) and controlled The electrical path to the device 67 is turned off, and the application of voltage to the controlled device 67 is stopped (S23). Next, the information on whether the identified FET 68 (see FIG. 1) is the first FET 21 to the sixth FET 26 (see FIG. 1) and the voltage ON / OFF information are recorded in the history of the RAM 12 together with the controlled time information. The information is stored in the information storage area 302 (see FIG. 5) (S25). Then, the process proceeds to S10.

  When the short circuit detection circuit 13 (see FIG. 1) detects a short circuit in S17 (S17: YES), or when the ground fault detection circuit 14 (see FIG. 1) detects a ground fault in S19 (S19: YES), First, the electromagnetic switch 16 (see FIG. 1) is controlled by the CPU 10 (see FIG. 1), and between the power source 15 (see FIG. 1), the FET 68 (see FIG. 1), and the controlled device 67 (see FIG. 1). The electric circuit is opened, and the energization to the controlled device 67 whose applied voltage is ON is cut off (S29). This prevents overcurrent from flowing to the machine tool 1 (see FIG. 1) and the controlled device 67 (see FIG. 1), thereby preventing the occurrence of a failure.

  Next, in this state, for the FET 68 (see FIG. 1) whose gate signal is controlled so that the voltage applied to the controlled device 67 (see FIG. 1) is turned on, the drain signal to the source signal are turned off. The gate signal is controlled. As a result, the electric circuit to the controlled device 67 (see FIG. 1) connected to all the FETs 68 is interrupted (S31). Next, of the history information stored in the history information storage area 302 of the RAM 12 (see FIG. 5), history information at the time when a short circuit or a ground fault occurs (hereinafter referred to as “latest history information”) is read. The latest history information includes information on which FET was turned on at the time of occurrence of a short circuit or a ground fault. Then, based on the connected controlled device information stored in the connected controlled device information storage area 303 (see FIG. 5) of the RAM 12, the short circuit or the ground fault occurs in the connected controlled devices 67. The controlled device whose applied voltage is in the ON state is identified. Then, the specified controlled device 67 is displayed on the display device 62 (see FIG. 1) (S33).

  Thus, the operator can recognize the controlled device 67 (see FIG. 1) to which a voltage is applied when a short circuit or a ground fault occurs. The occurrence of a short circuit or a ground fault occurs in a portion to which a voltage is applied in the controlled device 67 and connection lines 31 to 38 (see FIG. 1) connecting the machine tool 1 (see FIG. 1) and the controlled device 67. This occurs at the timing of voltage application to the controlled device 67 when there is a portion that has short-circuited with SG or FG. Therefore, it can be specified that the controlled device 67 displayed on the display device 62 (see FIG. 1) is a cause of a short circuit or a ground fault. As a result, the operator can identify the controlled device 67 that is a cause of occurrence of a short circuit or a ground fault at an early stage. At this time, when there are a plurality of controlled devices 67 whose applied voltages are in an ON state when a short circuit or a ground fault occurs, at least one of the controlled devices 67 among the controlled devices 67 is selected. However, this may be a cause of short circuit or ground fault.

  After the controlled device 67 (see FIG. 1) whose applied voltage was in the ON state at the time of occurrence of a short circuit or ground fault is identified and displayed on the display device 62 (see FIG. 1), it is then continuously executed. In order to prompt the operator to shift to the recovery process (see FIG. 7, which will be described later), the display unit 62 displays whether or not there is a shift to the recovery work, and makes the worker select in this state (S35). ). In the restoration process, when there are a plurality of controlled devices 67 whose applied voltages are in an ON state when a short circuit or a ground fault occurs, in any of the controlled devices 67, the cause of the occurrence of the short circuit or the ground fault is It is identified whether it occurred. If the operator selects an instruction to shift to the recovery process (S35: YES), the process shifts to the recovery process (S37, see FIG. 7, described later). On the other hand, if the controlled device displayed in S33 is the only one and the controlled device that has caused the short circuit or ground fault at this time can be specified by the operator, no instruction to select the restoration work is given. Therefore (S35: NO), the main process is terminated.

  Next, restoration processing executed by the CPU 10 (see FIG. 1) provided in the control board 2 will be described with reference to FIG. In the recovery process that is executed when the operator gives an instruction to select the transition to the recovery process (S35: YES, see FIG. 6), the controlled device 67 (FIG. 1) that is the cause of the occurrence of a short circuit or ground fault. In addition, when the controlled device 67 is the switch 66 (see FIG. 1), a process for specifying in more detail the part where the ground fault has occurred is executed. .

  As shown in FIG. 7, in the restoration process, first, the connected controlled device information stored in the connected controlled device information storage area 303 (see FIG. 4) of the RAM 12 is read and connected to the controlled device 67 connected. The type (see FIG. 1) is determined. When the connected controlled device 67 does not include the switch 66 (see FIG. 1) (S41: NO), the process proceeds to S45. When the connected controlled device 67 includes the switch 66 (see FIG. 1) (S41: YES), it is then determined whether or not all of these switches 66 are turned off. (S43). Specifically, it is determined as follows. First, the display device 62 (see FIG. 1) displays a message prompting the operator to turn off all the switches 66. Next, an input signal from the operation panel 61 (see FIG. 1) is monitored (S43: NO). Then, when it is confirmed that the operator has turned off all the switches 66 by recognizing the operation content via the operation panel 61, it is determined that all the switches 66 have been turned off (S43: YES). ), The process proceeds to S45.

  Note that the determination of whether or not the switch 66 (see FIG. 1) is turned off is not limited to the method described above. For example, a control signal line capable of feeding back the ON / OFF state of the switch 66 (see FIG. 1) to the CPU 10 (see FIG. 1) is provided between the switch 66 and the CPU 10, and this control signal line is monitored. Thus, it may be determined that all the switches 66 have been turned off.

  Next, the latest history information stored in the history information storage area 302 (see FIG. 5) of the RAM 12 is read (S45). And FET68 (refer FIG. 1) which is turning ON the voltage application to the controlled apparatus 67 (refer FIG. 1) is extracted from the newest history information (S47). In this state, the electromagnetic switch 16 (see FIG. 1) is controlled, the electric circuit between the power source 15 (see FIG. 1) and the controlled device 67 is closed, and energization is resumed (S49).

  In S31 of FIG. 6, the gate signals of all FETs 68 (see FIG. 1) are controlled so that the interval between the drain signal and the source signal is OFF. That is, even if the electromagnetic switch 16 (see FIG. 1) is closed and the electric circuit between the power source 15 (see FIG. 1) and the FET 68 is energized, the voltage is not applied to the controlled device 67 (see FIG. 1). Not applied. Therefore, in the part to which voltage is applied in the controlled device 67, or in the connection lines 31 to 38 (see FIG. 1) connecting the machine tool 1 (see FIG. 1) and the controlled device 67, short-circuiting with SG or FG. Even if there is a part that has been removed, no short circuit or ground fault should occur.

  However, in a state where the electromagnetic switch 16 (see FIG. 1) is closed and the electric circuit between the power source 15 (see FIG. 1) and the FET 68 (see FIG. 1) is energized, the short circuit detection circuit 13 (see FIG. 1). Detects a short circuit (S51: YES), or if the ground fault detection circuit 14 (see FIG. 1) detects a ground fault (S51: NO, S53: YES), the machine tool 1 (not the controlled device 67 side) It is determined that there is a cause of occurrence of a short circuit and a ground fault inside the side (see FIG. 1). Then, the display 62 (see FIG. 1) is notified that a short circuit or a ground fault has occurred inside the machine tool 1 side and notified to the operator (S55), the restoration process is terminated, and the main process ( Return to FIG.

  In this way, it is possible to notify the operator that the cause of the occurrence of the short circuit and the ground fault exists inside the machine tool 1 (see FIG. 1). In addition, the cause of occurrence of a short circuit and a ground fault assumed here is a short circuit or a ground fault generated by a short circuit between patterns or wirings on the control board 2 (see FIG. 1), for example.

  On the other hand, the electromagnetic switch 16 (see FIG. 1) is closed and the electric circuit between the power source 15 (see FIG. 1) and the FET 68 (see FIG. 1) is energized, and the short circuit detection circuit 13 (see FIG. 1). Does not detect a short circuit (S51: NO) and the ground fault detection circuit 14 (see FIG. 1) does not detect a ground fault (S53: NO), then, the FET 68 extracted in S47 (FIG. 1) Any one of (see) is selected (S57).

  Next, it is determined whether the controlled device 67 (see FIG. 1) connected to the source signal of the selected FET 68 (see FIG. 1) is the relay 65 (see FIG. 1) or the switch 66 (see FIG. 1). Then, the short-circuit or ground fault occurrence specifying process corresponding to the type of the controlled device 67 is executed. With reference to the connected controlled device information stored in the connected controlled device information storage area 303 (see FIG. 4) of the RAM 12, the controlled device 67 connected to the source signal of the selected FET 68 is switched to the switch 66 (FIG. 1). It is determined whether or not (refer to S59). If it is determined that it is not the switch 66 (S59: NO), since the controlled device 67 connected to the source signal of the selected FET 68 is the relay 65, any of the plurality of relays 65 is selected. Processing for identifying whether a short circuit or ground fault has occurred is executed (S67 to S71). On the other hand, if it is determined that the controlled device 67 connected to the source signal of the selected FET 68 is the switch 66 (S59: YES), the connection connecting the switch 66 and the CPU 10 (see FIG. 1). A short-circuit ground fault region specifying process is performed to specify at which part of the lines 35 to 38 (see FIG. 1) the ground fault has occurred (S61, see FIG. 8, described later).

  It is determined that the controlled device 67 (see FIG. 1) connected to the source signal of the FET 68 (see FIG. 1) selected in S57 is not the switch 66 (see FIG. 1) but the relay 65 (see FIG. 1). If this occurs (S59: NO), then the gate signal is controlled so that the drain signal to the source signal of the selected FET 68 (see FIG. 1) are turned on, and voltage application to the relay 65 connected to the source signal is performed. Is turned on (S67). In this state, when a short circuit is detected by the short circuit detection circuit 13 (see FIG. 1) (S69: YES), a portion to which a voltage is applied in the relay 65 connected to the FET 68 that is turned on, or the machine tool 1 (FIG. 1). 1) and the relay 65 (see FIG. 1), there is a portion that is short-circuited with SG. It is determined that a short circuit has occurred.

  Further, when a ground fault is detected by the ground fault detection circuit 14 (see FIG. 1) (S69: NO, S71: YES), a portion to which a voltage is applied in the relay 65 (see FIG. 1), or the machine tool 1 In connection lines 31 to 34 (see FIG. 1) connecting the relay 65 to the relay 65 (see FIG. 1), there is a portion that is short-circuited with the FG. It is determined that a ground fault has occurred where overcurrent flows. This makes it clear that the relay 65 with the applied voltage turned ON has a cause of occurrence of a short circuit and a ground fault.

  Next, in order to prevent the machine tool 1 (see FIG. 1) and the relay 65 (see FIG. 1) from failing due to overcurrent flow, control is performed to open the electromagnetic switch 16 (see FIG. 1). Thus, the power supply between the power source 15 (see FIG. 1) and the FET 68 (see FIG. 1) is cut off (S79). Next, in step S67, the gate signal is controlled so that the gate signal is controlled again so that the drain signal and the source signal are turned off with respect to the FET 68 that has been controlled and the gate signal is controlled so that the drain signal and the source signal are turned on. (S81). Then, referring to the connected controlled device information storage area 303 (see FIG. 4) of the RAM 12, the FET 68 in which the gate signal is controlled so as to turn off the drain signal to the source signal in S81. The relay 65 connected to the FET 68 having the generation factor is specified (S83). Then, the specified controlled device 67 is displayed on the display device 62 (see FIG. 1) (S85). Then, the process ends and the process returns to the main process (see FIG. 6).

  By executing the above processing, the operator short-circuits and grounds the relay 65 (see FIG. 1) displayed on the display device 62 (see FIG. 1) after the recovery processing of the machine tool 1 (see FIG. 1). It becomes possible to specify the relay 65 having the cause of the occurrence of the entanglement. As a result, the operator can quickly identify the relay 65 having a cause of occurrence of a short circuit and a ground fault. And it becomes possible to prevent the recurrence of the short circuit and the ground fault by early handling the short circuit of the specified relay 65 and the ground fault factor.

  On the other hand, if a short circuit and a ground fault are not detected in the short circuit detection circuit 13 or the ground fault detection circuit 14 (see FIG. 1) (S69: NO, S71: NO), the FET 68 selected in S57 and turned on in S67 ( 1 is turned OFF (S73), and it is determined whether or not the above-described processing has been executed for all the FETs 68 that are turned ON in the latest history information read in S45 (S75). If there is an unprocessed FET 68 (S75: NO), one of the remaining FETs 68 is selected (S65), and the process returns to S59 and is repeated. On the other hand, when all the FETs 68 have been processed (S75: YES), the electromagnetic switch 16 (see FIG. 1) is opened and the process returns to the main process (see FIG. 6).

  On the other hand, when it is determined that the controlled device 67 (see FIG. 1) connected to the source signal of the FET 68 (see FIG. 1) selected in S57 is the switch 66 (see FIG. 1) (S59: YES). In addition, a short-circuit ground fault location specifying process is performed to specify at which part of the connection lines 35 to 38 (see FIG. 1) connecting the switch 66 and the CPU 10 (see FIG. 1) a short-circuit and a ground fault have occurred. (S61).

  With reference to FIG. 8, the short-circuit ground fault region specifying process (S61, see FIG. 7) will be described. As shown in FIG. 8, in the short-circuit ground fault region specifying process, first, the voltage of the contacts 55 b and 56 b (see FIG. 1) on the side where the FETs 25 and 26 are not connected in the switches 55 and 56 (see FIG. 1). A monitoring process is executed via the buffers 27 and 28 (see FIG. 1) (S91). The voltage at the contacts 55b and 56b is monitored in order to specify a detailed ground fault occurrence location in the switches 55 and 56 (details will be described later). In this state, in S31 (see FIG. 6), the gate signal is controlled so that the drain signal to the source signal of the FETs 25 and 26 to which the switches 55 and 56 are connected is turned off, and S43 ( In FIG. 7), the switches 55 and 56 are OFF. Therefore, the output voltage from the buffers 27 and 28 is 0V.

  Next, the gate signal of the FET 68 (see FIG. 1) selected in S57 (see FIG. 7) is controlled to turn ON between the drain signal and the source signal, and the switches (55, 56 (FIG. 1) connected to the source signal. The applied voltage is turned ON (S93). In this state, it is determined whether a short circuit or a ground fault occurs. When a ground fault is detected by the ground fault detection circuit 14 (see FIG. 1) (S95: YES), first, an overcurrent flows due to the occurrence of a ground fault, and the machine tool 1 (see FIG. 1) and the switch 66 (see FIG. 1). In order to prevent failure, the electromagnetic switch 16 (see FIG. 1) is opened to open the circuit between the power source 15 (see FIG. 1) and the FET 68, and the switch is de-energized. (S99). Next, it is determined that the cause of the occurrence of the ground fault exists in the switch (one of 55 and 56 (see FIG. 1)) in which the applied voltage is ON and the connection lines 35 to 38 (see FIG. 1). Further, the detailed processing for identifying the location where the ground fault occurs is performed (S107 to S117).

  At this time, the switch 66 (see FIG. 1) is turned off in S43 (see FIG. 7). Therefore, in the state where the applied voltage is turned on in this state, that is, in a state where the connection lines 35 and 36 (see FIG. 1) are short-circuited with FG, a ground fault occurs due to the voltage application being turned on. It is assumed that In order to confirm this, the output voltage from the buffers 27 and 28 (see FIG. 1) started monitoring in S91 is the power supply at the time of ground fault detection (see S95) by the ground fault detection circuit 14 (see FIG. 1). It is confirmed whether or not the displacement is greater than 15 (see FIG. 1) (S107).

  At the time of ground fault detection (see S95) by the ground fault detection circuit 14 (see FIG. 1), the output voltage from the buffers 27 and 28 (see FIG. 1) is not displaced so as to be equal to or higher than the power supply 15 (see FIG. 1). (S107: NO), it is determined that a ground fault has occurred in the connection lines 35 and 36 (see FIG. 1). The reason is that the switches 55 and 56 are OFF in this state, and only the connection lines 35 and 36 are applied with voltage. For example, in the example shown in FIG. 1, as indicated by “A” in FIG. 1, it is determined that a ground fault has occurred in this portion as a result of the connection lines 35 and 36 being short-circuited with the FG.

  Next, the source signal of the FET 68 (see FIG. 1) selected in S57 (see FIG. 7) based on the connected controlled device information stored in the connected controlled device information storage area 303 (see FIG. 4) of the RAM 12. The switch 66 (see FIG. 1) connected to the line is specified (S113). Then, in order to notify the operator of the specified switch (either 55 or 56) and the specified connection line (either 35 or 36), the display 62 (see FIG. 1) displays the switch. (S117). Then, the process ends, and the process returns to the recovery process (see FIG. 7).

  On the other hand, when the ground fault is detected by the ground fault detection circuit 14 (see FIG. 1) (see S95), the output voltage from the buffers 27 and 28 (see FIG. 1) is displaced so as to be equal to or higher than the power supply 15 (see FIG. 1). In the case (S107: YES), it is determined that a ground fault has occurred in both the connection lines 35 and 36 (see FIG. 1) and the connection lines 37 and 38 (see FIG. 1). The detected output voltages from the buffers 27 and 28 are such that, as a result of the connection lines 35 and 37 and the connection lines 36 and 38 being short-circuited to FG, the voltage applied to the connection lines 35 and 36 is the connection line 36. , 38, it is determined that this occurred. For example, in the example shown in FIG. 1, as indicated by “B” in FIG. 1, both the connection lines 35 and 37 and the connection lines 36 and 38 are short-circuited with the FG, resulting in a ground fault in this portion. It is judged that

  Next, the source signal of the FET 68 (see FIG. 1) selected in S57 (see FIG. 7) based on the connected controlled device information stored in the connected controlled device information storage area 303 (see FIG. 5) of the RAM 12. The switch 66 (see FIG. 1) connected to the line is specified (S115). In order to notify the operator of the specified switch (one of 55 and 56) and the specified connection line (one of 35 and 37, or 36 and 38), the display device 62 ( (See FIG. 1) (S117). Then, the process ends, and the process returns to the recovery process (see FIG. 7).

  On the other hand, with the applied voltage to the switch 66 (see FIG. 1) connected to the source signal of the FET 68 (see FIG. 1) selected in S57 (see FIG. 7) turned on (S93), the ground fault detection circuit 14 A case where a ground fault is not detected (see S95: NO) will be described. In this case, first, the display device 62 (see FIG. 1) displays a message prompting the operator to turn on the switch 66 whose applied voltage is turned off. In this state, the process waits until it is confirmed that the switch 66 is turned on (S97: NO). If it is confirmed that the switch 66 is turned on (S97: YES), the process proceeds to S101.

  Note that the determination of whether or not the switch 66 (see FIG. 1) is ON is not limited to the above-described method. For example, a control signal line capable of feeding back the ON / OFF state of the switch 66 to the CPU 10 (see FIG. 1) is provided between the switch 66 and the CPU 10, and the control signal line is monitored, whereby the switch It may be determined that 66 is turned on.

  Next, it is determined whether or not a ground fault has been detected by the ground fault detection circuit 14 (see FIG. 1) with the switch 66 (see FIG. 1) turned on (S101). When the output signal of the ground fault detection circuit 14 is determined and it is determined that a ground fault has occurred (S101: YES), an overcurrent flows due to the occurrence of the ground fault, and the machine tool 1 (see FIG. 1) and the switch In order to prevent 66 from failing, the electromagnetic switch 16 (see FIG. 1) is opened to open the circuit between the power supply 15 (see FIG. 1) and the FET 68 (see FIG. 1), and to the switch 66. Is turned off (S109).

  And it is judged that the ground fault has generate | occur | produced in the connection lines 37 and 38 (refer FIG. 1) (S111). When the switches 55 and 56 are turned off, no voltage is applied to the connection lines 37 and 38. On the other hand, when the switches 55 and 56 are turned on, a voltage is applied to the connection lines 37 and 38, and a ground fault occurs. Is determined to have occurred. For example, in the example shown in FIG. 1, as indicated by “C” in FIG. 1, it is determined that a ground fault has occurred in this portion as a result of a short circuit between the connection lines 37 and 38 and FG. In order to notify the operator of the identified switch (either 55 or 56) and the identified connection line (either 37 or 38), the display 62 (see FIG. 1) is displayed. (S117). Then, the process ends, and the process returns to the recovery process (see FIG. 7).

  On the other hand, when the ground fault is not detected by the ground fault detection circuit 14 (see FIG. 1) even when the switch 66 (see FIG. 1) is turned on, the display 62 (see FIG. 1) is used. The fact that the ground fault location is unknown is displayed (S105), the process is terminated, and the process returns to the recovery process (see FIG. 7).

  In the recovery process, as shown in FIG. 7, when the ground fault occurrence part is specified in the short-circuit ground fault region specifying process (see FIG. 8) (S63: YES), the process is terminated as it is and the main process (FIG. 6) is performed. Return to Browse. On the other hand, when the ground fault occurrence site is not specified (S63: NO), the process proceeds to S73, and which of the remaining FETs 68 (see FIG. 1) has a short circuit and a ground fault generated. Continue to be judged.

  As described above, in the case where control is performed by switching ON / OFF of the voltage applied to the controlled device 67 to which the machine tool 1 is connected, information on the ON / OFF history of voltage application is stored. When a short circuit and a ground fault are detected by the short circuit detection circuit 13 and the ground fault detection circuit 14, the electromagnetic switch 16 is opened to cut off the energization, and the applied voltage is detected when the short circuit and the ground fault are detected. The controlled device 67 that is turned on is displayed on the display device 62. As a result, the operator can quickly identify the controlled device 67 that is the cause of the occurrence of a short circuit and a ground fault, and can take measures early to restore control.

  In addition, the applied voltage is turned on again in order for the controlled device 67 that has turned on the applied voltage when a short circuit and a ground fault are detected. Then, the controlled device 67 whose applied voltage is ON when the short circuit and the ground fault occur again is identified as the controlled device 67 that is the cause of the short circuit and the ground fault, and is displayed on the display device 62. As a result, when there are a large number of controlled devices 67 whose applied voltage is turned ON when a short circuit and a ground fault are detected, the controlled object that causes a short circuit and a ground fault is selected. The device 67 can be specified, and control can be restored by taking measures at an early stage.

  Further, when the controlled device 67 to be connected is the switch 66, it is possible to identify which part of the connection line connected to the switch 66 has a ground fault and display it on the display device 62. Is possible. As a result, the operator can take a countermeasure by specifying the site where the ground fault occurs in detail.

  Note that the FET 68 in FIG. 1 corresponds to the “conduction switching means” of the present invention, and the CPU 10 that performs control to switch the FET 68 on and off in S11 and S21 shown in FIG. 6 serves as the “device control means” of the present invention. Equivalent to. In S15 and S25 in FIG. 6, the CPU 10 that performs processing for storing the history information of the FET 68 ON / OFF in the history information storage area 302 of the RAM 12 in FIGS. Correspondingly, the output signals from the short circuit detection circuit 13 and the ground fault detection circuit 14 shown in FIG. 1 are judged, and S17 and S19 shown in FIG. 6, S51, S53, S69, S71 shown in FIG. 7, and FIG. In S <b> 95 and S <b> 101, the CPU 10 that performs processing for detecting occurrence of a short circuit and a ground fault corresponds to the “detection unit” of the present invention. Further, the electromagnetic switch 16 shown in FIG. 1 corresponds to the “switch” of the present invention, and a process of opening the electromagnetic switch 16 in S29 in FIG. 6, S79 in FIG. 7, and S99 shown in FIG. The CPU 10 to perform corresponds to the “opening means” of the present invention, the history information shown in FIG. 5 corresponds to the “history information” of the present invention, and the latest history information is displayed on the display device 62 in S33 shown in FIG. The CPU 10 that performs the process corresponds to “notification means” of the present invention.

  Further, the CPU 10 that performs the process of closing the electromagnetic switch in S49 in FIG. 7 after turning off all the FETs 68 in S31 shown in FIG. 6 corresponds to the “closing means” of the present invention, and is shown in FIG. The CPU 10 that performs the process of turning on the FET 68 in S67 and S93 shown in FIG. 8 corresponds to the “apparatus history control means” of the present invention. In S83 shown in FIG. 7, the process of specifying the controlled apparatus 67 is performed. The CPU 10 to perform corresponds to the “specifying means” of the present invention.

  Further, the voltage range of the connection portion 76 and the reference power supply 74 in the short circuit detection circuit 13 shown in FIG. 2 corresponds to the “predetermined range” of the present invention, and the output signal from the short circuit detection circuit 13 is detected to short circuit. The CPU 10 that performs the process of determining the occurrence of occurrence corresponds to the “short circuit detecting means” of the present invention. Further, the CPU 10 that detects the output circuit from the ground fault detection circuit 14 shown in FIG. 3 and determines the occurrence of the ground fault corresponds to the “ground fault detection means” of the present invention.

  Further, the switches 55 and 56 in FIG. 1 correspond to the “switch” of the present invention, the contacts 55a and 56a in the switches 55 and 56 correspond to the “first contact” of the present invention, and 55b and 56b correspond to the main switch. The CPU 10 that corresponds to the “second contact” of the invention and that performs the process of detecting the output voltage from the buffers 27 and 28 in S107 shown in FIG. 8 corresponds to the “switch voltage detecting means” of the invention.

  1 corresponds to the “predetermined value” of the present invention, and when the output voltage is not detected in S107 shown in FIG. 8, the connection line 35 or 36 is grounded in S113. The CPU 10 that performs the process of specifying that a fault has occurred corresponds to the “first connection line ground fault determination unit” of the present invention, and performs the process of displaying the specified connection line on the display device 62 in S117. The CPU 10 corresponds to the “first connection line notification unit” of the present invention. In addition, when the output voltage is detected in S107 shown in FIG. 8, the CPU 10 that performs processing for specifying that a ground fault has occurred in the connection lines 35, 37 or 36, 38 in S115 is the present invention. The CPU 10 that performs the process of displaying the identified connection line on the display device 62 in S117 corresponds to the “first second connection line notification unit” of the present invention. Equivalent to. In addition, when a ground fault is detected in S101 shown in FIG. 8, the CPU 10 that performs the process of specifying that a ground fault has occurred in the connection lines 37 and 38 in S111 is the “second” of the present invention. The CPU 10 that performs the process of displaying the identified connection line on the display device 62 in S117 corresponds to the “second connection line notification unit” of the present invention.

  In addition, this invention is not limited to the said embodiment, The change in the range which does not change the summary of invention is possible. In the above embodiment, four relays 65 and two switches 66 are connected to the machine tool 1, respectively, but the type and quantity of the controlled device 67 are not limited to this. Therefore, controlled devices other than relays and limit switches may be connected, and the number thereof may be other than the number in the above embodiment.

  In the above embodiment, the short circuit detection circuit 13 has a circuit configuration including the OP amplifier 73, and the ground fault detection circuit 14 has a circuit configuration including the photocoupler 85. However, the present invention is not limited to this. Therefore, the short circuit detection circuit 13 and the ground fault detection circuit 14 may be realized by other circuit configurations.

  Further, in the above embodiment, it is determined that a voltage displacement has occurred when the output signals from the buffers 27 and 28 are displaced more than the voltage of the power supply 15, but the present invention is not limited to this. Absent. Therefore, the presence or absence of voltage displacement may be determined based on another threshold voltage.

  Moreover, in the said embodiment, the connection lines 35-37 connected to the switch 66 contact the housing frame 3 as a generation | occurrence | production factor of a short circuit and a ground fault when the controlled apparatus 67 connected is the switch 66. Assuming a short circuit between the connection lines 35 to 37 and the FG, which is generated by doing this, only the cause of the ground fault is specified, but it is not limited to this. Therefore, when a short circuit between the voltage application portion and SG in the switch 66 occurs, the short circuit detection circuit 13 detects the short circuit and executes a process of notifying that the short circuit has occurred in the switch 66 from the display device 62. It doesn't matter.

It is a block diagram which shows an example of the hardware constitutions of the machine tool. 3 is a schematic diagram of a circuit configuration of a short circuit detection circuit 13. FIG. 2 is a schematic diagram of a circuit configuration of a ground fault detection circuit 14. FIG. 3 is a schematic diagram showing an outline of a storage area of a RAM 12. FIG. 3 is a schematic diagram showing an outline of a history information storage area 302 of a RAM 12. FIG. 6 is a main flowchart of control processing and recovery processing of the controlled device 67. It is a subroutine flowchart of a recovery process. It is a subroutine flowchart of the process which specifies a short circuit ground fault generation | occurrence | production site | part.

DESCRIPTION OF SYMBOLS 1 Machine tool 13 Short circuit detection circuit 14 Ground fault detection circuit 15 Power supply 16 Electromagnetic switch 21 First FET
21 First FET
22 Second FET
23 Third FET
24 Fourth FET
25 Fifth FET
26 Sixth FET
26, 27, 28 Buffer 31, 32, 33, 34, 35, 36, 37, 38 Connection line 51 First relay 52 Second relay 53 Third relay 54 Fourth relay 55 First switch 56 Second switch 55a, 55b 56a, 56b Contact 62 Display 66 Switch 67 Controlled device 68 FET
73 OP amplifier 302 History information storage area

Claims (6)

A machine tool that controls the controlled device by switching applied voltages to a plurality of controlled devices to be connected,
A power source for applying a voltage to the controlled device;
Conduction switching means for switching the applied voltage to each controlled device by switching conduction / non-conduction of the electric circuit between the power source and each controlled device;
Device control means for controlling the conduction switching means, sequentially switching the voltage applied to each controlled device, and controlling each controlled device;
Storage means for storing a history of switching of applied voltage by the device control means;
Detection means for detecting the occurrence of a short circuit or a ground fault;
A switch that opens and closes an electrical circuit between the power source and the controlled device;
When the detection means detects a short circuit or a ground fault, the opening means for controlling the switch to open the electric circuit between the power source and the controlled device and to cut off the energization;
A notification means for notifying the history information that is the history information stored in the storage means to the outside in a state where the energization between the power source and the controlled device is interrupted by the opening means ;
In the state where the detection means detects a short circuit or a ground fault, and the opening means controls the switch to cut off the energization to the controlled device, the conduction switching means is controlled to control the power supply and all the A closing means for turning off the electrical circuit between the controlled device, controlling the switch again to close the electrical circuit between the power source and the controlled device, and resuming energization;
When the detection means detects a short circuit or a ground fault based on the history information stored in the storage means in a state where the energization between the power source and the controlled device is resumed by the closing means. Device history control means for switching the applied voltage by controlling the conduction switching means that has switched the electric circuit to the conduction state;
While the applied voltage is switched by the device history control unit, a short circuit or a ground fault is detected again by the detection unit, and the energization between the power source and the controlled device is interrupted by the opening unit. When the short circuit or the ground fault is detected by the detection means, the specifying means for specifying the controlled device that is electrically connected to the power source,
The notifying means notifies the controlled device specified by the specifying means to the outside . The detection means includes
Short-circuit detecting means for detecting that the voltage of the power source is equal to or lower than a predetermined range, and determining that a short circuit has occurred in which the power source and a signal ground that is a reference potential for the power source are conducted;
When a current flows between the frame ground of the machine tool connected to the ground and the signal ground, it is detected that a potential difference has occurred between the frame ground and the signal ground, and the power source and the frame are detected. The machine tool according to claim 1, further comprising a ground fault detection unit that determines that a ground fault that is electrically connected to the ground has occurred. The controlled device is a switch that switches between conduction / non-conduction between the first contact and the second contact,
In the case where the switch is provided with a first connection line connecting the conduction switching means and the first contact, and a second connection line connected to the second contact of the switch,
The machine tool is
The machine tool according to claim 2 , further comprising switch voltage detection means for detecting a voltage of the second connection line. In a state where the first contact and the second contact of the switch are non-conductive,
While the voltage applied to the switch is being sequentially switched by the device history control means, the ground fault detection means detects the occurrence of a ground fault simultaneously with the detection by the ground fault detection means. A first connection line ground fault determination means for determining that a ground fault has occurred in the first connection line when the switch voltage detection means does not detect a voltage greater than or equal to a predetermined value;
The machine tool according to claim 3 , further comprising first connection line notification means for notifying the first connection line determined by the first connection line ground fault determination means to the outside. In a state where the first contact and the second contact of the switch are non-conductive,
While the voltage applied to the switch is being sequentially switched by the device history control means, the ground fault detection means detects the occurrence of a ground fault simultaneously with the detection by the ground fault detection means. A first second connection line that determines that a ground fault has occurred simultaneously in both the first connection line and the second connection line when the switch voltage detection means detects a voltage greater than or equal to a predetermined value. Ground fault judgment means,
Claim 3 or, characterized in that a first second connecting line notifying means for notifying said second connecting line and the first connection line is determined by the first second connection line ground fault judging means to the outside 4. The machine tool according to 4 . In a state where the first contact and the second contact of the switch are conductive,
A ground fault occurs in the second connection line when the ground fault detection means detects the occurrence of a ground fault while the applied voltage to the switch is being sequentially switched by the device history control means. A second connection line ground fault judging means for judging that
The machine tool according to any one of claims 3 to 5, characterized in that a second connecting line notifying means for notifying the second connecting line is determined by the second connecting line ground fault judging means to the outside .

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