Control device and control system

Abstract

The present invention suppresses the occurrence of failure and malfunction in an encoder via a communication line when removing or attaching the encoder from / to a control device. A control device (2) controls a motor (4) on the basis of a detection signal from an encoder (3) that detects the operating position of the motor (4). The control device (2) comprises a communication unit (22), a pull-up resistor (R1), a first power supply (26), a first switch (SW1), and a control unit (27). The communication unit (22) transmits and receives a detection signal to / from the encoder (3) via a communication line (L2). The pull-up resistor (R1) is connected to the communication line (L2). The first switch (SW1) is provided to a first electrical circuit (L7) connecting the first power supply (26) and the pull-up resistor (R1) and causes the first electrical circuit (L7) to conduct current or be shut off. The control unit (27) controls the first switch (SW1).

Description

Control device and control system

[0001] The present disclosure relates to a control device and a control system, and more particularly to a control device that controls a motor based on a detection signal from an encoder that detects the operating position of the motor, and a control system that includes this control device.

[0002] The substrate-related operation machine described in Patent Document 1 includes a multi-axis rotary servo amplifier (controller), an encoder, and a motor. The encoder detects the rotation angle of the motor. The multi-axis rotary servo amplifier can communicate with the encoder via a multiplexed communication device. The multi-axis rotary servo amplifier controls the motor based on the detection signal of the encoder received via the multiplexed communication device.

[0003] International Publication No. 2017 / 179156

[0004] In the substrate-related operation machine of Patent Document 1, if the communication lines of the multiplexed communication device are connected to a power supply via a pull-up resistor, when the encoder is attached to the control device, a surge current from the power supply may flow to the encoder via the pull-up resistor and the communication lines, causing a malfunction or failure of the encoder. Also, when the encoder is removed from the control device while voltage is still being applied to the communication lines, a malfunction or failure of the encoder may occur.

[0005] An object of the present disclosure is to provide a control device and a control system that can prevent failures or malfunctions from occurring in the encoder via a communication line when the encoder is removed from or attached to the control device.

[0006] A control device according to one aspect of the present disclosure controls a motor based on a detection signal from an encoder that detects the operating position of the motor. The control device includes a communication unit, a pull-up resistor, a first power supply, a first switch, and a control unit. The communication unit transmits and receives the detection signal to and from the encoder via a communication line. The pull-up resistor is connected to the communication line. The first switch is provided in a first electrical path connecting the first power supply and the pull-up resistor, and connects and disconnects the first electrical path. The control unit controls the first switch.

[0007] A control system according to another aspect of the present disclosure includes the control device, the encoder, and the motor.

[0008] The control device and control system of the present disclosure have the advantage of being able to prevent failures or malfunctions in the encoder via the communication line when the encoder is removed from or attached to the control device.

[0009] FIG. 1 is a configuration diagram of a control system according to an embodiment. FIG. 2 is a configuration diagram of a control system according to Modification 1. FIG. 3 is a configuration diagram of a control system according to Modification 2. FIG. 4 is a flowchart illustrating a first operation example of a control unit according to Modification 2. FIG. 5 is a flowchart illustrating a second operation example of a control unit according to Modification 2. FIG. 6 is a configuration diagram of a control system according to Modification 3. FIG. 7 is a configuration diagram of a control system according to Modification 4. FIG. 8 is a partially enlarged view of FIG. 7, and is a configuration diagram illustrating a connector connected state. FIG. 9 is a configuration diagram illustrating a connector separated state in a control system according to Modification 4.

[0010] (1) Embodiments Hereinafter, a control device and a control system according to an embodiment of the present disclosure will be described with reference to the drawings.

[0011] (1-1) Overview of the Control Device FIG. 1 is a configuration diagram of a control system 1 according to this embodiment. As shown in FIG. 1, a control device 2 according to this embodiment controls a motor 4 based on a detection signal from an encoder 3 that detects the operating position of the motor 4. Here, the motor 4 is, for example, a motor such as a servo motor used in semiconductor manufacturing equipment or a production robot. Note that the motor 4 is not limited to a motor such as a servo motor used in semiconductor manufacturing equipment or a production robot. The control device 2 includes a communication unit 22, a pull-up resistor R1, a first power supply (e.g., a pull-up power supply 26), a first switch SW1, and a control unit 27. The communication unit 22 is, for example, a communication element having an electronic circuit, and is capable of transmitting and receiving detection signals to and from the encoder 3 via a communication line L2. The pull-up resistor R1, the termination resistor R2, and the pull-down resistor R3 are electrically connected to the communication line L2. The first switch SW1 is provided on a first electrical path (e.g., electrical path L7) that connects the first power supply (pull-up power supply 26) and the pull-up resistor R1, and turns on and off the first electrical path (electrical path L7). The control unit 27 controls the first switch SW1.

[0012] According to this configuration, the encoder 3 can be attached to and detached from the control device 2 with the first switch SW1 cutting off the first electric circuit (electric circuit L7). This makes it possible to prevent a malfunction or failure of the encoder 3 via the communication line L2 when attaching and detaching the encoder 3 to the control device 2. More specifically, it is possible to prevent a malfunction or failure of the encoder 3 caused by a surge current flowing from the first power supply (pull-up power supply 26) through the communication line L2 to the encoder 3 when attaching the encoder 3 to the control device 2, and to prevent a malfunction or failure of the encoder 3 caused by a sudden interruption of the communication line L2 (forced disconnection of the communication line L2) when removing the encoder 3 from the control device 2.

[0013] The control system 1 according to this embodiment also includes a control device 2, an encoder 3, and a motor 4. According to this configuration, the control system 1 including the control device 2 can be provided.

[0014] (1-2) Detailed Description of the Control System As shown in FIG. 1, the control system 1 includes a control device 2 (also called a servo amplifier), an encoder 3, a motor 4, and a main power supply 5.

[0015] In this control system 1, the rotational position (operating position) of the motor 4 is detected by the encoder 3, and the control device 2 controls the motor 4 based on the detection result of the encoder 3. This control system 1 is suitable for controlling, as the motor 4, for example, a servo motor used in semiconductor manufacturing equipment or a production robot.

[0016] (1-2-1) Main Power Supply The main power supply 5 is an AC power supply such as a commercial power supply. As shown in Fig. 1, the main power supply 5 supplies a power supply voltage to the control device 2, the encoder 3, and the motor 4. In this embodiment, the power supply voltage is supplied from the main power supply 5 to the control device 2, and the power supply voltage is supplied from the control device 2 to the encoder 3 and the motor 4. The main power supply 5 is connected to a power supply input terminal T1 of the control device 2 via a main power switch SW0.

[0017] (1-2-2) Control Device The control device 2 controls the motor 4 based on the rotational position of the motor 4 detected by the encoder 3. As shown in Fig. 1, the control device 2 includes a plurality of external terminals (power input terminal T1, power output terminal T2, communication terminals T3 and T4, and power supply terminals T5 to T7), an encoder power supply circuit 21, a communication unit 22, a motor power supply circuit 23, an inverter 24, a PWM (pulse width modulation) signal generation unit 25, a pull-up power supply 26, a pull-up resistor R1, a termination resistor R2, a pull-down resistor R3, a first switch SW1, a second switch SW2, first to third short-circuit switches SW3 to SW5, and a control unit 27.

[0018] The power supply input terminal T1 is a terminal for inputting a voltage (AC voltage) from the main power supply 5. The power supply input terminal T1 is connected to the main power supply 5 via the main power switch SW0.

[0019] The power supply output terminal T2 is a terminal for outputting the voltage (DC voltage) generated by the encoder power supply circuit 21 to the encoder 3. The power supply output terminal T2 is connected to a power supply input terminal T8 (described later) of the encoder 3 via a power cable L12.

[0020] The power cable L12 and electrical paths L11 and L13 (described later) form a power line L1 that connects the encoder power circuit 21 and the power circuit 31 in the encoder 3.

[0021] The communication terminals T3 and T4 are terminals for communication connection with the encoder 3. The communication terminals T3 and T4 are connected to communication terminals T9 and T10 (described later) of the encoder 3 via communication cables L22 and L32.

[0022] The communication cable L22 and the electric circuits L21 and L23 described below constitute one communication line L2 of two communication lines L2 and L3 connecting the communication unit 22 and the communication unit 33 in the encoder 3. The communication cable L32 and the electric circuits L31 and L33 described below constitute the other communication line L3 of the two communication lines L2 and L3.

[0023] The power supply terminals T5 to T7 are terminals for outputting the three-phase AC voltage generated by the motor power supply circuit 23 to the motor 4. The power supply terminals T5 to T7 are connected to power supply terminals T11, T12, and T13 of the motor 4 via power supply cables L42, L52, and L62.

[0024] The power supply cable L42 and an electric circuit L41 (described later) constitute a U-phase power supply line L4 that connects the inverter 24 and a U-phase power supply terminal T11 of the motor. The power supply cable L52 and an electric circuit L51 (described later) constitute a V-phase power supply line L5 that connects the inverter 24 and a V-phase power supply terminal T12 of the motor. The power supply cable L62 and an electric circuit L61 (described later) constitute a W-phase power supply line L6 that connects the inverter 24 and a W-phase power supply terminal T13 of the motor.

[0025] The encoder power supply circuit 21 generates a power supply voltage (DC voltage) for the encoder from the power supply voltage (AC voltage) of the main power supply 5. The encoder power supply circuit 21 includes, for example, an AC / DC converter and a transformer. The AC / DC converter converts the power supply voltage (AC voltage) of the main power supply 5 into a DC voltage. The transformer transforms the DC voltage converted by the AC / DC converter into a DC voltage having a predetermined voltage value (for example, 5 V).

[0026] The encoder power supply circuit 21 has an input section 21a and an output section 21b. The input section 21a is a section that inputs the power supply voltage of the main power supply 5, which is input to a power supply input terminal T1, to the encoder power supply circuit 21, and is connected to the power supply input terminal T1. The output section 21b is a section that outputs a DC voltage generated by the encoder power supply circuit 21 from the encoder power supply circuit 21, and is connected to a power supply output terminal T2 via an electrical path L11. A second switch SW2 is arranged on the electrical path L11.

[0027] The second switch SW2 is disposed on the electric line L11 and turns on or off the electric line L11 based on a control signal from the control unit 27. This switches on or off the supply of power supply voltage from the encoder power supply circuit 21 to the encoder 3.

[0028] The communication unit 22 performs data communication with a communication unit 33 (described later) of the encoder 3 in response to a control signal from the control unit 27. The communication unit 22 performs two-wire communication with the communication unit 33 of the encoder 3, for example, using two communication lines L2 and L3. The communication unit 22 receives rotational position information transmitted from the communication unit 33 of the encoder 3, and transmits control signals for the encoder 3 to the communication unit 33 of the encoder 3. The rotational position information is information about the rotational position of the motor 4 detected by the encoder 3.

[0029] The communication unit 22 has a transmission mode and a reception mode. The transmission mode is an operation mode in which the communication unit 22 transmits transmission data (e.g., control signals) to the communication unit 33 of the encoder 3 via the communication lines L2 and L3. The reception mode is an operation mode in which the communication unit 22 receives reception data (e.g., rotational position information) from the communication unit 33 of the encoder 3 via the communication lines L2 and L3. The operation mode of the communication unit 22 is switched between the transmission mode and the reception mode in response to a control signal from the control unit 27.

[0030] The communication unit 22 has two signal input / output units 22b and 22c, which are used to input and output data for data communication (the control signal and rotational position information) and are connected to communication terminals T3 and T4 by electrical paths L21 and L31, respectively.

[0031] The pull-up power supply 26 is a DC power supply (e.g., 5 V) for pulling up the electrical path L21 (i.e., the portion of the communication line L2 inside the control device 2). The pull-up power supply 26 is generated, for example, from the main power supply 5 input to the power input terminal T1.

[0032] The pull-up resistor R1, the termination resistor R2, and the pull-down resistor R3 are connected in series between the pull-up power supply 26 and ground. The pull-up resistor R1, the termination resistor R2, and the pull-down resistor R3 are arranged in this order from the pull-up power supply 26 toward ground. An electrical path L21 is connected to the connection point between the pull-up resistor R1 and the termination resistor R2. An electrical path L31 is connected to the connection point between the termination resistor R2 and the pull-down resistor R3. A first switch SW1 is disposed on the electrical path L7 connecting the pull-up power supply 26 and the pull-up resistor R1. Switching the first switch SW1 on and off switches the electrical path L7 between conductive and non-conductive, and this switching switches the enable and disable of the pull-up resistor R1 of the communication line L2. Enabling the pull-up resistor R1 pulls up the input voltage of the signal input / output unit 22b of the communication unit 22. The input voltage of the signal input / output unit 22c of the communication unit 22 is pulled down by the pull-down resistor R3.

[0033] The first switch SW1 is disposed on the electrical path L7 and switches the electrical path L7 between conductive and non-conductive states based on a control signal from the control unit 27. This switches between enabling and disabling pull-up of the voltage of the electrical path L21 (i.e., the input voltage of the signal input / output unit 22b of the communication unit 22).

[0034] The motor power supply circuit 23 generates a power supply voltage (DC voltage) for the motor from the power supply voltage of the main power supply 5. The motor power supply circuit 23 includes, for example, an AC / DC converter and a transformer. The AC / DC converter converts the power supply voltage (AC voltage) of the main power supply 5 into a DC voltage. The transformer transforms the DC voltage converted by the AC / DC converter into a DC voltage having a predetermined voltage value.

[0035] The inverter 24 converts the DC voltage generated by the motor power supply circuit 23 into a three-phase AC voltage and supplies the converted three-phase AC voltage to the motor 4. The inverter 24 has, for example, six transistors. The six transistors are configured as three pairs of transistors, each pair consisting of two transistors connected in series. The three pairs are connected in parallel to each other. The DC voltage generated by the motor power supply circuit 23 is applied in parallel to the three pairs of transistors. The junctions of the two transistors in the three pairs are connected to three power supply terminals T5 to T7 via electrical paths L41, L51, and L61, respectively, and are connected to three power supply terminals T11, T12, and T13 of the motor 4 via power supply cables L42, L52, and L62, respectively.

[0036] A first short-circuiting switch SW3, a second short-circuiting switch SW4, and a third short-circuiting switch SW5 are disposed between the electric paths L41, L51, and L61 and the ground, respectively.

[0037] The first shorting switch SW3, the second shorting switch SW4, and the third shorting switch SW5 constitute a dynamic brake for stopping the motor 4. The first shorting switch SW3 is disposed on a branch electric path connecting the U-phase power supply line L4 (more specifically, the electric path L41) and ground, and switches the conduction and interruption of the branch electric path based on a control signal from the control unit 27. The second shorting switch SW4 is disposed on a branch electric path connecting the V-phase power supply line L5 (more specifically, the electric path L51) and ground, and switches the conduction and interruption of the branch electric path based on a control signal from the control unit 27. The third shorting switch SW5 is disposed on a branch electric path connecting the W-phase power supply line L6 (more specifically, the electric path L61) and ground, and switches the conduction and interruption of the branch electric path based on a control signal from the control unit 27. By turning on the first short-circuiting switch SW3, the second short-circuiting switch SW4, and the third short-circuiting switch SW5, the discharge time of the motor 4 can be shortened, thereby allowing the motor 4 to be stopped more quickly.

[0038] In this embodiment, short-circuit switches (first short-circuit switch SW3 to third short-circuit switch SW5) are provided between each of the three power supply lines L4 to L6 and the ground, but it is sufficient that a short-circuit switch is provided in at least one of the three power supply lines L4 to L6.

[0039] The PWM signal generating unit 25 performs PWM (Pulse Width Modulation) control of the six transistors of the inverter 24 based on a control signal from the control unit 27. Through this control, the inverter 24 converts the DC voltage from the motor power supply circuit 23 into a three-phase AC voltage and switches between supplying and stopping the converted three-phase AC voltage to the motor 4. Furthermore, through the above control, the inverter 24 changes the rotation speed of the motor 4.

[0040] The control unit 27 controls the controlled objects (e.g., the first switch SW1, the second switch SW2, the communication unit 22, and the first to third short-circuiting switches SW3 to SW5) by outputting control signals to each of the controlled objects. More specifically, the control unit 27 controls the on / off switching of the first switch SW1 using the control signal, thereby controlling the switching between conduction and interruption of the electrical path L7. This controls the enable / disable of pull-up of the input voltage of the signal input / output unit 22b of the communication unit 22. The control unit 27 also controls the on / off switching of the second switch SW2 using the control signal, thereby controlling the switching between conduction and interruption of the electrical path L11 (i.e., the power line L1). This controls the switching between supply and cut-off of the power supply voltage supplied from the encoder power supply circuit 21 to the power supply circuit 31 of the encoder 3. The control unit 27 also switches the operation mode of the communication unit 22 between a transmission mode and a reception mode using the control signal. This switches the operation mode of the communication unit 22 between the transmission mode and the reception mode. The control unit 27 also controls the on / off switching of the first short-circuiting switch SW3 to the third short-circuiting switch SW5 using the control signal, thereby controlling the switching between conduction and interruption between the power supply lines L4 to L6 and the ground, thereby controlling the switching between activation and deactivation of the dynamic brake of the motor 4.

[0041] (1-2-3) Encoder As shown in Fig. 1, the encoder 3 detects the rotational position (operating position) of the motor 4. In this embodiment, the motor 4 is a rotary motor, so the encoder 3 detects the rotational position of the motor 4. However, if the motor 4 is a linear motor that operates linearly, the encoder 3 detects the movement position of the motor.

[0042] The encoder 3 includes a power input terminal T8, communication terminals T9 and T10, a power supply circuit 31, a detection circuit 32, a communication unit 33, a pull-up resistor R4, a termination resistor R5, and a pull-down resistor R6.

[0043] The power supply input terminal T8 is a terminal for inputting a voltage (DC voltage) from the encoder power supply circuit 21. The power supply input terminal T8 is connected to the power supply circuit 31 by an electric line L13. The power supply input terminal T8 is also connected to the power supply output terminal T2 of the control device 2 via a power cable L12.

[0044] The communication terminals T9 and T10 are terminals for communication connection with the control device 2. The communication terminals T9 and T10 are connected to the communication terminals T3 and T4 of the control device 2 via communication cables L22 and L32.

[0045] The power supply circuit 31 transforms (steps down) the DC voltage (e.g., 5 V) supplied from the encoder power supply circuit 21 of the control device 2 to generate a power supply voltage (e.g., 3 V) for the internal circuits of the encoder 3 (e.g., the detection circuit 32 and the communication unit 33).

[0046] The detection circuit 32 operates using the power supply voltage supplied from the power supply circuit 31 and detects the rotational position of the motor 4. The detection circuit 32 detects the rotational position (rotational angle) of the motor 4, for example, by detecting the rotational position (rotational angle) of a rotor fixed to the rotating shaft of the motor 4.

[0047] The communication unit 33 is, for example, a communication element having an electronic circuit, and performs data communication with the communication unit 22 of the control device 2. As described above, the communication unit 33 performs two-wire communication with the communication unit 22 using, for example, two communication lines L2 and L3. The communication unit 33 transmits the detection result of the detection circuit 32 (rotational position information related to the rotational position of the motor 4) to the communication unit 22, and receives control signals for the encoder 3 from the communication unit 22. The communication unit 33 has two signal input / output units 33b and 33c. The two signal input / output units 33b and 33c are units that input and output data for data communication (the above-mentioned control signal and rotational position information), and are connected to communication terminals T9 and T10 by electrical paths L23 and L33, respectively.

[0048] The pull-up resistor R4, the termination resistor R5, and the pull-down resistor R6 are connected in series between the electrical path L13 and ground. The pull-up resistor R4, the termination resistor R5, and the pull-down resistor R6 are arranged in this order from the electrical path L13 toward ground. The electrical path L23 is connected to the connection point between the pull-up resistor R4 and the termination resistor R5. This pulls up the input voltage of the signal input / output unit 33b of the communication unit 33. The electrical path L33 is connected to the connection point between the termination resistor R5 and the pull-down resistor R6. This pulls down the input voltage of the signal input / output unit 33c of the communication unit 33.

[0049] (1-2-4) Motor The motor 4 is, for example, a three-phase AC rotary servo motor, and is operated by a three-phase AC voltage supplied from the inverter 24 of the control device 2. The motor 4 is, for example, a servo motor used in semiconductor manufacturing equipment or a production robot. Note that the motor 4 is not limited to servo motors used in semiconductor manufacturing equipment or production robots. The motor 4 has three power supply terminals T11, T12, and T13 to which the three-phase AC voltage supplied from the inverter 24 of the control device 2 is input. The three power supply terminals T11, T12, and T13 are connected to three power supply terminals T5, T6, and T7 of the control device 2 via three power supply cables L42, L52, and L62, respectively. Note that the motor 4 may also be a linear motor that reciprocates linearly.

[0050] (1-2-5) Features of the Control System Configuration In the control device 2, a first switch SW1 is disposed on the electrical path L7 connecting the pull-up power supply 26 and the pull-up resistor R1. Therefore, the encoder 3 can be attached to and detached from the control device 2 with the electrical path L7 interrupted by the first switch SW1 (i.e., with the pull-up of the electrical path L21 (i.e., the portion of the communication line L2 within the control device 2) disabled). This prevents the encoder 3 from malfunctioning or failing via the communication line L2 when the encoder 3 is attached to or detached from the control device 2. More specifically, this prevents a surge current from flowing from the pull-up power supply 26 through the communication line L2 to the encoder 3 when the encoder 3 is attached to the control device 2, causing a malfunction or failure in the encoder 3, and prevents a sudden interruption of the communication line L2 (e.g., forcible disconnection of the communication line L2) when the encoder 3 is detached from the control device 2 from malfunction or failure in the encoder 3.

[0051] (1-3) Main Effects As described above, the control device 2 according to the embodiment controls the motor 4 based on a detection signal from the encoder 3, which detects the operating position of the motor 4. The control device 2 includes a communication unit 22, a pull-up resistor R1, a pull-up power supply 26 (first power supply), a first switch SW1, and a control unit 27. The communication unit 22 is capable of transmitting and receiving detection signals to and from the encoder 3 via a communication line L2. The pull-up resistor R1 is connected to the communication line L2. The first switch SW1 is provided in an electrical path L7 (first electrical path) that connects the pull-up power supply 26 and the pull-up resistor R1, and turns the electrical path L7 on and off. The control unit 27 controls the first switch SW1.

[0052] With this configuration, the encoder 3 can be attached to and detached from the control device 2 with the electric path L7 (first electric path) interrupted by the first switch SW1 (i.e., with the pull-up of the electric path L7 disabled). This makes it possible to prevent a malfunction or failure of the encoder 3 via the communication line L2 when attaching and detaching the encoder 3 to the control device 2 (effect). More specifically, it is possible to prevent a malfunction or failure of the encoder 3 caused by a surge current flowing from the pull-up power supply 26 (first power supply) through the communication line L2 to the encoder 3 when attaching the encoder 3 to the control device 2, and to prevent a malfunction or failure of the encoder 3 caused by a sudden interruption of the communication line L2 (for example, by forcibly disconnecting the communication line L2) when removing the encoder 3 from the control device 2.

[0053] Furthermore, the pull-up power supply 26 (first power supply) is a power supply separate from the encoder power supply circuit 21 that supplies a power supply voltage to the encoder 3. With this configuration, the above-described effects can be achieved in a configuration in which the pull-up power supply 26 is a power supply separate from the encoder power supply circuit 21.

[0054] The control system 1 according to this embodiment also includes a control device 2, an encoder 3, and a motor 4. According to this configuration, the control system 1 including the control device 2 described above can be provided.

[0055] (2) Modifications Modifications of the above embodiment will be described below. In the following description, the same parts as those in the above embodiment will be denoted by the same reference numerals and explanations will be omitted, and only the differences will be described. Furthermore, the above embodiment and the following modifications may be combined.

[0056] (2-1) Modification 1 Fig. 2 is a configuration diagram of a control system 1 according to Modification 1. In the control device 2 according to the above embodiment, the encoder power supply circuit 21 and the pull-up power supply 26 are separate configurations. However, as shown in Fig. 2, the pull-up power supply 26 may be omitted, and the encoder power supply circuit 21 may also serve as the pull-up power supply.

[0057] More specifically, as shown in FIG. 2 , the control device 2 according to the first modification does not include the pull-up power supply 26 and the second switch SW2 in the control device 2 according to the above embodiment. Furthermore, in the control device 2 according to the first modification, the electrical path L11 connects the encoder power supply circuit 21 and the power output terminal T2, as in the above embodiment. In the first modification, the first switch SW1 is provided on the electrical path L11 and switches the electrical path L11 between conductive and non-conductive. Similarly to the above embodiment, the electrical path L7 connects the pull-up resistor R1 and one end of the first switch SW1 (the end on the encoder 3 side in the first modification).

[0058] In the control device 2 according to the first modification, the encoder power supply circuit 21 (first power supply) is connected to the pull-up resistor R1 via a first electrical path (i.e., an electrical path formed by electrical paths L11 and L7). A first switch SW1 is provided in the first power supply (more specifically, the electrical path L11) and switches the electrical path L11 between conductive and non-conductive states. This switching between conductive and non-conductive states switches the pull-up resistor R1 between enabled and disabled states.

[0059] Furthermore, in the control device 2 according to the first modification, the encoder power supply circuit 21 supplies a power supply voltage to the encoder 3 via the power supply line L1, as in the above embodiment. In the first modification, a portion of the power supply line L1 (electrical path L11) is shared with the first power supply. A first switch SW1 is further provided on the power supply line L1 (more specifically, the electrical path L11) and switches the power supply line L1 between conductive and cut-off states. This switching between conductive and cut-off switches between supplying and cutting off the power supply voltage from the encoder power supply circuit 21 to the encoder 3.

[0060] Furthermore, in the control device 2 according to the first modified example, the control unit 27 is configured in the same manner as the control unit 27 of the above embodiment, except that the function of controlling the second switch SW2 is omitted.

[0061] As described above, in the first modification, the first switch SW1 has both the function of switching on and off the supply of power supply voltage from the encoder power supply circuit 21 to the encoder 3, and the function of switching on and off the pull-up resistor R1.

[0062] According to the first modification, the encoder power supply circuit 21 is used both as an encoder power supply circuit and as a pull-up power supply. The first switch SW1 can also be used to turn on and off the first electrical path (the electrical path consisting of the electrical paths L11 and L7) and the power line L1 (the electrical path consisting of the electrical paths L11 and L13 and the power cable L12). This reduces the number of components.

[0063] Furthermore, with the power line L1 cut off by the first switch SW1, the encoder 3 can be attached to and detached from the control device 2. This prevents a surge current from flowing from the encoder power supply circuit 21 through the power line L1 to the encoder 3 when the encoder 3 is attached to the control device 2, causing a breakdown or malfunction in the encoder 3, and prevents a sudden interruption of the power line L1 (for example, forcibly pulling out the power line L1) when the encoder 3 is removed from the control device 2.

[0064] (2-2) Modification 2 (2-2-1) Description of Configuration Fig. 3 is a configuration diagram of a control system 1 according to Modification 2. As shown in Fig. 3, in the control device 2 according to Modification 2, in the control device 2 according to the above embodiment, the control unit 27 controls the control targets (for example, the first switch SW1, the second switch SW2, the communication unit 22, and the first to third short-circuit switches SW3 to SW5) based on a trigger signal input from the external device 7.

[0065] More specifically, the control device 2 according to the second modification further includes a signal input terminal T14 as an external terminal.

[0066] The signal input terminal T14 is connected to a signal input unit 27b of the control unit 27. The signal input terminal T14 is connected to the external device 7 via a signal cable L9.

[0067] The external device 7 is, for example, a programmable logic controller (PLC) or an amplifier. The external device 7 outputs a trigger signal to the signal input terminal T14 of the control device 2 via the signal cable L9 in response to, for example, an operation by an operator. The trigger signal is a signal that instructs the control unit 27 to start execution of a predetermined process for the control object (for example, a series of processes for multiple control objects). The external device 7 outputs different types of trigger signals (for example, first to third trigger signals described below) in response to the operation content of the operator.

[0068] In the control device 2 according to the second modification, the control unit 27 is configured in the same manner as the control unit 27 of the above embodiment, except that it controls the above-mentioned controlled object based on a trigger signal input to the signal input terminal T14.

[0069] (2-2-2) Description of Operation Next, the operation of the control unit 27 will be described.

[0070] (2-2-2-1) First Operation Example of Control Unit 27 Fig. 4 is a flowchart illustrating a first operation example of the control unit 27 according to Modification 2. When removing the encoder 3 from the control device 2, the operator operates the external device 7 to cause the external device 7 to output a first trigger signal. Then, when the control unit 27 in the control device 2 receives the first trigger signal from the external device 7 via the signal input terminal T14, it executes a series of processes of steps S1 to S4 shown in Fig. 4 for the communication unit 22, the first switch SW1, and the second switch SW2.

[0071] More specifically, as shown in FIG. 4 , upon receiving the first trigger signal (S1), the control unit 27 first switches the operation mode of the communication unit 22 to the receive mode (S2). The control unit 27 then switches the first switch SW1 from on to off (S3). This interrupts the electrical path L7, disabling the pull-up resistor R1 in the control device 2. Furthermore, the interruption of the electrical path L7 prevents the power supply current from the pull-up power supply 26 from flowing through the communication line L2, the pull-up resistor R4, and the electrical path L13 to the encoder 3. Finally, the control unit 27 switches the second switch SW2 from on to off (S4). This stops the power supply voltage from the encoder power supply circuit 21 from being supplied to the encoder 3 through the power line L1.

[0072] In this way, when the encoder 3 is removed from the control device 2, the first switch SW1 is switched off and then the second switch SW2 is switched off. As a result, when the second switch SW2 is in the cut-off state (i.e., when the power supply to the encoder 3 is turned off), the supply of power current from the pull-up power supply 26 to the power supply circuit 31 in the encoder 3 through the communication line L2, pull-up resistor R4, and electrical path L13 is stopped, thereby preventing the encoder 3 from operating unstably.

[0073] Furthermore, when the encoder 3 is removed from the control device 2, as described above, the operation mode of the communication unit 22 is switched to the reception mode, and then the first switch SW1 is switched from on to off, and the second switch SW2 is switched from off to on. This prevents the communication unit 22 of the control device 2 from going into the transmission mode and applying a voltage to the communication line L2 (which is undesirable) when the second switch SW2 is in the off state (i.e., the power supply to the encoder 3 is in the off state).

[0074] (2-2-2-2) Second Operation Example of Control Unit 27 Fig. 5 is a flowchart illustrating a second operation example of the control unit 27 according to Modification 2. When attaching the encoder 3 to the control device 2, the operator operates the external device 7 to cause the external device 7 to output a second trigger signal. Then, when the control unit 27 in the control device 2 receives the second trigger signal from the external device 7 via the signal input terminal T14, the control unit 27 executes a series of processes of steps S11 to S14 shown in Fig. 5 for the communication unit 22, the first switch SW1, and the second switch SW2.

[0075] 5, when the control unit 27 receives the second trigger signal (S11), it first switches the second switch SW2 from off to on (S12). This causes the power supply voltage from the encoder power supply circuit 21 to be supplied to the encoder 3 through the power supply line L1. Then, the control unit 27 switches the first switch SW1 from off to on (S13). This brings the electrical path L7 into conduction, enabling the pull-up resistor R1 in the control device 2. Then, the control unit 27 switches the operating mode of the communication unit 22 to either the transmission mode or the reception mode (S14).

[0076] In this way, when the encoder 3 is attached to the control device 2, the second switch SW2 is switched on and then the first switch SW1 is switched on. As a result, when the second switch SW2 is in the cut-off state (i.e., when the power supply to the encoder 3 is off), the supply of power current from the pull-up power supply 26 to the power supply circuit 31 in the encoder 3 through the communication line L2, pull-up resistor R4, and electrical path L13 is stopped, thereby preventing the encoder 3 from operating unstably.

[0077] Furthermore, when the encoder 3 is attached to the control device 2, as described above, the second switch SW2 is switched on, and then the first switch SW1 is switched on, and the operation mode of the communication unit 22 is switched to the reception mode or the transmission mode. This prevents the communication unit 22 of the control device 2 from entering the transmission mode and applying a voltage to the communication line L2 (i.e., undesirable) when the power supply to the encoder 3 is off (i.e., the second switch SW2 is off).

[0078] In the present embodiment, the control unit 27 performs both the on / off switching operation of each of the first switch SW1 and the second switch SW2 and the switching of the operation mode of the communication unit 22. However, the control unit 27 may omit the switching of the operation mode of the communication unit 22 and only perform the on / off switching of the first switch SW1 and the second switch SW2.

[0079] (2-2-2-3) Third Operation Example of the Control Unit When the motor 4 is removed from the control device 2, the operator operates the external device 7 to cause the external device 7 to output a third trigger signal. Then, upon receiving the third trigger signal from the external device 7 via the signal input terminal T14, the control unit 27 in the control device 2 executes the following processing for the first short-circuiting switch SW3 to the third short-circuiting switch SW5.

[0080] More specifically, when the control unit 27 receives the third trigger signal, it switches the first short-circuiting switch SW3 to the third short-circuiting switch SW5 from OFF to ON. This causes the electrical energy in the motor 4 to be discharged to ground through the first short-circuiting switch SW3 to the third short-circuiting switch SW5. This discharge completes the discharging of the motor 4 in a short time. Then, after the discharging of the motor 4 is completed (i.e., after a predetermined time has elapsed since the start of discharging), the motor 4 is removed from the control device 2.

[0081] In this way, when the motor 4 is to be removed from the control device 2, the first shorting switch SW3 to the third shorting switch SW5 are turned on immediately before the motor 4 is removed, thereby applying a dynamic brake to the motor 4. This reduces the discharge time of the motor 4, thereby shortening the time required to remove the motor 4 from the control device 2. This is particularly effective in a configuration in which the encoder 3 and motor 4 are integrated. In this case, the control unit 27 acquires the first trigger signal and the third trigger signal from the external device 7 immediately before the encoder 3 and motor 4 are removed from the control device 2.

[0082] (2-3) Modification 3 FIG. 6 is a configuration diagram of a control system 1 according to modification 3.

[0083] In the control device 2 according to the second modification, the control unit 27 controls the control objects (for example, the first switch SW1, the second switch SW2, the first short-circuiting switch SW3 to the third short-circuiting switch SW5, and the communication unit 22) based on a trigger signal from the external device 7. In contrast, in the control device 2 according to the third modification, as shown in FIG. 6 , the control unit 27 controls the control objects based on a trigger signal from a trigger button 8 (operation unit) provided in the control device 2. The trigger button 8 is an example of an operation unit that accepts operations from an operator. The operation unit is not limited to a button-type operation unit such as the trigger button 8.

[0084] More specifically, the control device 2 of variant example 3 is configured in the same manner as the control device 2 of variant example 2, except that it has a trigger button 8 instead of the signal input terminal T14.

[0085] The trigger button 8 includes a plurality of buttons that correspond one-to-one to different types of trigger signals (for example, the first to third trigger signals in Modification 2). When the operator selectively presses the plurality of buttons, the buttons output the corresponding types of trigger signals to the control unit 27. The trigger button 8 is arranged, for example, on the surface of the housing of the control device 2.

[0086] In the control device 2 according to the third modification, when the control unit 27 acquires each type of trigger signal (for example, the first to third trigger signals of the second modification) from the trigger button 8, it performs processing on the control object according to each type of trigger signal, as in the first to third operation examples of the control unit of the second modification.

[0087] According to the third modification, the control target can be controlled by inputting an operation to the trigger button 8 (operation unit).

[0088] (2-4) Modification 4 (2-4-1) Description of Configuration FIG. 7 is a configuration diagram of a control system according to Modification 4. As shown in FIG.

[0089] In the second modification, the control unit 27 of the control device 2 controls the controlled objects (for example, the first switch SW1, the second switch SW2, the first short-circuiting switch SW3 to the third short-circuiting switch SW5, and the communication unit 22) based on a trigger signal from the external device 7. In contrast, in the fourth modification, as shown in Fig. 7 , the control device 2 and the encoder 3 are detachably connected by the first connector 9 and the second connector 10, and the control unit 27 of the control device 2 controls the controlled objects based on a trigger signal output in response to the attachment and detachment of the first connector 9 and the second connector 10.

[0090] 7 , the control device 2 of Modification 4 is different from the control device 2 of Modification 2 in that the signal input terminal T14 is omitted. Furthermore, the control device 2 of Modification 4 includes a first connector 9 instead of the power output terminal T2 and the communication terminals T3 and T4 of the control device 2 of Modification 2. One end of each of the power cable L12 and the communication cables L22 and L32 is connected to the second connector 10. Furthermore, the control device 2 of Modification 4 further includes a detector 11 that detects the connection / disconnection of the first connector 9 and the second connector 10 in the control device 2 of Modification 2.

[0091] The first connector 9 is, for example, a male connector. The first connector 9 is connected to the control device 2. More specifically, the first connector 9 is disposed so as to be exposed to the outside from the surface of the housing of the control device 2. Fig. 8 is a partial enlarged view of Fig. 7, illustrating the connector connection state. As shown in Fig. 8, the first connector 9 has a first connector housing 91, a male power output terminal M2, a pair of male communication terminals M3 and M4, and a pair of male first terminals M5 and M6.

[0092] The power output terminal M2, the pair of communication terminals M3 and M4, and the pair of first terminals M5 and M6 are accommodated and arranged within the first connector housing 91. The power output terminal M2 is connected to one end of an electric circuit L11 and is connected to the output portion of the encoder power supply circuit 21 via the electric circuit L11. The pair of communication terminals M3 and M4 are connected to one end of electric circuits L21 and L31, respectively, and are connected to the signal input / output portions 22b and 22c of the communication portion 22 via the electric circuits L21 and L31. Of the pair of first terminals M5 and M6, one first terminal M5 is connected to the signal input portion 27a of the control portion 27 via the electric circuit L8, and the other first terminal M6 is grounded.

[0093] The signal input section 27a of the control section 27 is connected to the second power supply 28 (voltage Vcc) via a resistor R7 and is also connected to one of the first terminals M5. That is, the second power supply 28 is connected to the signal input section 27a of the control section 27 and one of the first terminals M5 via the resistor R7.

[0094] The detection unit 11 detects attachment / detachment (connection and separation) of the first connector 9 and the second connector 10, and outputs a first level signal or a second level signal as a trigger signal to the signal input unit 27a of the control unit 27 in accordance with the connection / detachment. That is, the detection unit 11 changes the voltage input to the signal input unit 27a of the control unit 27 in accordance with the attachment / detachment of the first connector 9 and the second connector 10. The first level signal is a signal indicating that the first connector 9 and the second connector 10 have been separated, and is, for example, an H (High) level signal. The second level signal is a signal indicating that the first connector 9 and the second connector 10 have been connected, and is, for example, an L (Low) level signal.

[0095] The detection unit 11 is composed of a pair of first terminals M5, M6, a second power supply 28, and a resistor R7. The pair of first terminals M5, M6 are connected to and disconnected from a pair of second terminals M11, M12 (described below) of the second connector 10 in response to the connection and disconnection of the first connector 9 and the second connector 10. In this manner, the pair of first terminals M5, M6 are connected to and disconnected from the pair of second terminals M11, M12 (which are shorted to each other), thereby establishing and breaking electrical continuity between the pair of first terminals M5, M6. When electrical continuity between the pair of first terminals M5, M6 is broken, the voltage Vcc of the second power supply 28 is input to the signal input unit 27a of the control unit 27 as a first-level signal (H-level signal). When electrical continuity between the pair of first terminals M5, M6 is established, the signal input unit 27a of the control unit 27 is connected to ground, and the ground potential is input to the signal input unit 27a of the control unit 27 as a second-level signal (L-level signal).

[0096] The control unit 27 of the modified example 4 is configured in the same manner as the control unit 27 of the modified example 2, except that it controls the above-mentioned controlled object based on the trigger signal (first level signal or second level signal) input from the detection unit 11.

[0097] The second connector 10 is connected to the encoder 3 via a power cable L12 and communication cables L22 and L32. The second connector 10 is a female connector that is detachably connected to the male first connector 9. As shown in Fig. 8, the second connector 10 has a second connector housing 101, a female power input terminal M8, a pair of female communication terminals M9 and M10, and a pair of female second terminals M11 and M12.

[0098] The power input terminal M8, the pair of communication terminals M9, M10, and the pair of second terminals M11, M12 are housed and arranged within the second connector housing 101.

[0099] The power input terminal M8 is a female terminal that is detachably connected to the male power output terminal M2 of the first connector 9. The power input terminal M8 is connected to one end of the power cable L12 and is connected to the power supply circuit 31 of the encoder 3 via the power cable L12 and the electrical path L13. The pair of communication terminals M9, M10 are female terminals that correspond one-to-one to the pair of communication terminals M3, M4 of the first connector 9 and are detachably connected to the corresponding communication terminals. The pair of communication terminals M9, M10 are connected to one ends of the communication cables L22, L32, respectively, and are connected to the communication unit 33 of the encoder 3 via the communication cables L22, L32 and the electrical paths L23, L33. The pair of second terminals M11, M12 are female terminals that correspond one-to-one to the pair of male first terminals M5, M6 of the first connector 9 and are detachably connected to the corresponding first terminals. That is, the second terminal M11 corresponds to the first terminal M5, and the second terminal M12 is connected to the first terminal M6. The pair of second terminals M11 and M12 are short-circuited to each other.

[0100] (2-4-2) Description of the operation of the detection unit This section describes the operation when the detection unit 11 outputs a trigger signal (first trigger signal or second trigger signal) to the signal input unit 27a of the control unit 27 when the first connector 9 and the second connector 10 are connected and disconnected.

[0101] (2-4-2-1) Operation When the First Connector and the Second Connector are Separated FIG. 9 is a configuration diagram showing the connector separated state in the control system according to the fourth modification.

[0102] 9 , when the first connector 9 and the second connector 10 are separated, the first connector housing 91 of the first connector 9 and the second connector housing 101 of the second connector 10 are separated from each other. As a result, the power output terminal M2, the pair of communication terminals M3 and M4, and the pair of first terminals M5 and M6 in the first connector 9 are separated from the power input terminal M8, the pair of communication terminals M9 and M10, and the pair of second terminals M11 and M12 in the second connector 10, respectively. As a result of the pair of first terminals M5 and M6 being separated from the pair of second terminals M11 and M12 at this time, the input voltage to the signal input unit 27a of the control unit 27 is pulled up to the voltage Vcc of the second power supply 28. As a result, the voltage Vcc of the second power supply 28 is input to the signal input unit 27a of the control unit 27 as a first level signal (trigger signal).

[0103] When the control unit 27 acquires the first level signal (trigger signal), it controls the first switch SW1, the second switch SW2, and the communication unit 22 as described in the first operation example of the control unit of modified example 2, or it controls the first short-circuiting switch SW3 to the third short-circuiting switch SW5 to apply a dynamic brake to the motor 4 as described in the third operation example of the control unit of modified example 2.

[0104] 8 , when the first connector 9 and the second connector 10 are connected, the first connector housing 91 of the first connector 9 and the second connector housing 101 of the second connector 10 are connected to each other. As a result, the power output terminal M2, the pair of communication terminals M3 and M4, and the pair of first terminals M5 and M6 in the first connector 9 are connected to the power input terminal M8, the pair of communication terminals M9 and M10, and the pair of second terminals M11 and M12 in the second connector 10, respectively. The connection of the pair of first terminals M5 and M6 to the pair of second terminals M11 and M12 at this time connects the signal input unit 27a of the control unit 27 to ground via the electrical path L8, the pair of first terminals M5 and M6, and the pair of second terminals M11 and M12. As a result, the ground potential is input to the signal input unit 27a of the control unit 27 as a second-level signal (trigger signal).

[0105] When the control unit 27 acquires the second level signal (trigger signal), it controls the first switch SW1, the second switch SW2, and the communication unit 22 as described in the second operation example of the control unit of the second modified example.

[0106] (2-4-3) Advantages of Modification 4 According to Modification 4, the control targets (e.g., the first switch SW1, the second switch SW2, the first short-circuiting switch SW3 to the third short-circuiting switch SW5, and the communication unit 22) can be automatically controlled by connecting or disconnecting the first connector 9 and the second connector 10 (i.e., connecting or disconnecting the control device 2 and the encoder 3). In addition, the detection unit 11 can be configured with a simple structure.

[0107] (3) Aspects Based on the above-described embodiments and modifications, the present disclosure includes the following aspects.

[0108] A control device (2) according to a first aspect controls a motor (4) based on a detection signal from an encoder (3) that detects the operating position of the motor (4). The control device (2) includes a communication unit (22), a pull-up resistor (R1), a first power supply (26; 21), a first switch (SW1), and a control unit (27). The communication unit (22) transmits and receives the detection signal to and from the encoder (3) via a communication line (L2). The pull-up resistor (R1) is connected to the communication line (L2). The first switch (SW1) is provided in a first electrical path (L7; L11, L7) that connects the first power supply (26; 21) and the pull-up resistor (R1), and turns on and off the first electrical path (L7; L11, L7). The control unit (27) controls the first switch (SW1).

[0109] According to this configuration, the encoder (3) can be attached to and detached from the control device (2) with the first switch (SW1) cutting off the first electric circuit (L7; L11, L7). This makes it possible to prevent a malfunction or failure of the encoder (3) via the communication line (L2) when attaching or detaching the encoder (3) to the control device (2). More specifically, it is possible to prevent a surge current from flowing from the first power source (26; 21) through the communication line (L2) to the encoder (3) when attaching the encoder (3) to the control device (2), causing a malfunction or failure of the encoder (3), and to prevent a sudden interruption of the communication line (L2) (e.g., by forcible disconnection) when removing the encoder (3) from the control device (2).

[0110] In the control device (2) according to the second aspect, in the first aspect, the first power supply (21) is an encoder power supply circuit (21) that supplies a power supply voltage to the encoder (3) via a power supply line (L1). The first switch (SW1) is provided in the power supply line (L1) and turns on and off the power supply line (L1).

[0111] According to this configuration, the first power supply (21) can be used both as a pull-up power supply and as the encoder power supply circuit (21). Furthermore, the first switch (SW1) can turn on and off the first electrical path (the electrical path consisting of the electrical paths L11 and L7) and the power line (L1). As a result, the number of components can be reduced. Furthermore, the encoder (3) can be attached to and detached from the control device (2) with the power line (L1) turned off by the first switch (SW1).

[0112] In the control device (2) according to the third aspect, in the first aspect, the first power supply (26) is a pull-up power supply (26) and is a power supply separate from the encoder power supply circuit (21) that supplies a power supply voltage to the encoder (3).

[0113] According to this configuration, in a configuration in which the first power supply (26) is a pull-up power supply (26) separate from the encoder power supply circuit (21), the effect of the first aspect can be achieved.

[0114] The control device (2) according to a fourth aspect is the third aspect, and further includes an encoder power supply circuit (21) and a second switch (SW2). The second switch (SW2) connects the encoder power supply circuit (21) and the encoder (3) to each other and turns on and off the power line (L1). The control unit (27) further controls the second switch (SW2).

[0115] According to this configuration, the encoder (3) can be attached to and detached from the control device (2) while the power line (L1) is cut off by the second switch (SW2).

[0116] In the control device (2) according to the fifth aspect, in the fourth aspect, when the encoder (3) is removed from the control device (2), the control unit (27) cuts off the first electric circuit (L7) with the first switch (SW1) and then cuts off the power line (L1) with the second switch (SW2).

[0117] According to this configuration, when the encoder (3) is removed from the control device (2), it is possible to prevent the encoder (3) from breaking down or becoming defective.

[0118] In the control device (2) according to the sixth aspect, in the fourth or fifth aspect, when the encoder (3) is attached to the control device (2), the control unit (27) causes the power line (L1) to be conductive by the second switch (SW2), and then causes the first electric circuit (L7) to be conductive by the first switch (SW1).

[0119] According to this configuration, when the encoder (3) is attached to the control device (2), it is possible to prevent malfunctions or failures from occurring in the encoder (3).

[0120] In the control device (2) according to the seventh aspect, in the fifth aspect, the communication unit (22) is switchable between a transmission mode and a reception mode, and when the encoder (3) is detached from the control device (2), the control unit (27) switches the communication unit (22) to the reception mode and then causes the first switch (SW1) to interrupt the first electrical circuit (L7).

[0121] According to this configuration, when the encoder (3) is removed from the control device (2), the second switch (SW2) cuts off the power line (L1) to cut off the power supply to the encoder (3), and the communication unit (22) is in the transmission mode, and thus voltage is prevented from being applied to the communication line (L2). This makes it possible to prevent malfunctions and breakdowns of the encoder (3).

[0122] In the control device (2) according to the eighth aspect, in the sixth aspect, the communication unit (22) is switchable between a transmission mode and a reception mode. When the encoder (3) is attached to the control device (2), the control unit (27) switches the communication unit (22) to the transmission mode or the reception mode after conducting the first electrical circuit (L7) with the first switch (SW1).

[0123] According to this configuration, when the encoder (3) is attached to the control device (2), the transmission mode of the communication unit (22) can be prevented from applying voltage to the communication line (L2) when the power line (L1) is cut off by the second switch (SW2) and power supply to the encoder (3) is cut off, thereby preventing breakdowns and malfunctions of the encoder (3).

[0124] In the control device (2) according to the ninth aspect, in any one of the fourth to eighth aspects, the control unit (27) controls switching between a transmission mode and a reception mode of the first switch (SW1), the second switch (SW2), and the communication unit (22) based on a trigger signal from the external device (7).

[0125] According to this configuration, the switching between the transmission mode and the reception mode of the first switch (SW1), the second switch (SW2), and the communication unit (22) can be controlled by a trigger signal from the external device (7), thereby allowing the first switch (SW1) to be controlled by remote operation.

[0126] The control device (2) according to a tenth aspect is the control device (2) of any one of the fourth to eighth aspects, further including an operation unit (8) that accepts an operation for outputting a trigger signal. The control unit (27) controls the first switch (SW1, the second switch (SW2), and switching of the communication unit (22) between a transmission mode and a reception mode based on the trigger signal from the operation unit (8).

[0127] According to this configuration, the first switch (SW1), the second switch (SW2), and the communication unit (22) can be switched between the transmission mode and the reception mode by inputting an operation to the operation unit (8).

[0128] The control device (2) according to an eleventh aspect is any one of the first to eighth aspects, further including a first connector (9) and a detection unit (11). The first connector (9) is detachably connected to a second connector (10) connected to the encoder (3). The detection unit (11) detects the connection and disconnection of the first connector (9) and the second connector (10). The control unit (27) controls the first switch (SW1) based on the detection result of the detection unit (11).

[0129] According to this configuration, the first switch (SW1) can be automatically controlled by connecting or disconnecting the first connector (9) and the second connector (10) (i.e., connecting or disconnecting the control device (2) and the encoder (3)).

[0130] In a control device (2) according to a twelfth aspect, in the eleventh aspect, the second connector (10) has a pair of second terminals (M11, M12) short-circuited to each other. The detection unit (11) has a pair of first terminals (M5, M6) and a second power source (28). The pair of first terminals (M5, M6) are provided in the first connector (9) and are detachably connected to the pair of second terminals (M11, M12) by connection between the first connector (9) and the second connector (10). The second power source (28) is connected to one of the pair of first terminals (M5, M6) and a signal input unit (27a) of the control unit (27) via a resistor (R7). The other of the pair of first terminals (M5, M6) is connected to ground. The detection unit (11) changes the input voltage to the signal input unit (27a) of the control unit (27) in response to the connection and disconnection of the first connector (9) and the second connector (10).

[0131] According to this configuration, the detection unit (11) can be configured with a simple structure.

[0132] A control device (2) according to a thirteenth aspect is the same as in the ninth or tenth aspect, in which the motor (4) is a three-phase AC motor. The control device (2) includes an inverter (24) and at least one short-circuiting switch (SW3 to SW5). The inverter (24) supplies three-phase AC current to the motor (4) via three power feeders (L4 to L6). The at least one short-circuiting switch (SW3 to SW5) is provided in at least one of the three power feeders (L4 to L6) and establishes or breaks conduction between the provided power feeder and ground. A control unit (27) controls the short-circuiting switches (SW3 to SW5) based on a trigger signal.

[0133] According to this configuration, the shorting switches (SW3 to SW5) constitute a dynamic brake for the motor (4). This allows a dynamic brake to be applied to the motor (4) in response to a trigger signal from an external device (7) or an operation unit (8). As a result, the discharge time of the motor (4) is shortened, thereby shortening the time required to remove the motor (4) from the control device (2). This is particularly effective in a configuration in which the encoder (3) and the motor (4) are integrated.

[0134] A control system (1) according to a fourteenth aspect includes the control device (2) according to any one of the first to thirteenth aspects, an encoder (3), and a motor (4).

[0135] According to this configuration, a control system (1) including the control device (2) can be provided.

[0136] The control device and control system of the present disclosure can prevent failures or malfunctions in the encoder via a communication line when the encoder is removed from or attached to the control device, making the control device and control system of the present disclosure industrially useful.

[0137] REFERENCE SIGNS LIST 1 control system 2 control device 3 encoder 4 motor 7 external device 8 trigger button 9 first connector 10 second connector 11 detection unit 26 pull-up power supply (first power supply) 21 encoder power supply circuit (first power supply) 22 communication unit 24 inverter 27 control unit 27a, 27b signal input unit 33 communication unit L1 power line L2, L3 communication line L4 to L6 power supply line L7, L8, L11, L13, L21, L23, L31, L33, L41, L51, L61 electrical circuit M5, M6 first terminal M11, M12 second terminal R1, R4 pull-up resistor R2, R5 termination resistor R3, R6 pull-down resistor R7 resistor SW1 first switch SW2 second switch SW3 First short-circuit switch SW4 Second short-circuit switch SW5 Third short-circuit switch

Claims

1. A control device that controls a motor based on a detection signal from an encoder that detects an operating position of the motor, a communication unit that transmits and receives the detection signal to and from the encoder via a communication line; a pull-up resistor connected to the communication line; a first power source; a first switch provided in a first electrical path connecting the first power supply and the pull-up resistor, the first switch connecting and disconnecting the first electrical path; a control unit that controls the first switch.

2. the first power supply is an encoder power supply circuit that supplies a power supply voltage to the encoder via a power supply line; The control device according to claim 1 , wherein the first switch is provided in the power supply line to make the power supply line conductive and cut off the conductive state.

3. 2. The control device according to claim 1, wherein the first power supply is a pull-up power supply, and is a power supply separate from an encoder power supply circuit that supplies a power supply voltage to the encoder.

4. the encoder power supply circuit; a second switch that connects the encoder power supply circuit and the encoder to each other and cuts off the power supply line; The control device according to claim 3 , wherein the control unit further controls the second switch.

5. 5. The control device according to claim 4, wherein, when the encoder is removed from the control device, the control unit causes the first switch to interrupt the first electrical path, and then causes the second switch to interrupt the power line.

6. 6. The control device according to claim 4, wherein when the encoder is attached to the control device, the control unit first causes the second switch to make the power line conductive, and then causes the first switch to make the first electrical path conductive.

7. the communication unit is capable of switching between a transmission mode and a reception mode, The control device according to claim 5 , wherein, when the encoder is removed from the control device, the control unit switches the communication unit to the receiving mode and then causes the first switch to interrupt the first electrical path.

8. the communication unit is capable of switching between a transmission mode and a reception mode, 7. The control device according to claim 6, wherein, when the encoder is attached to the control device, the control unit switches the communication unit to the transmission mode or the reception mode after causing the first switch to make the first electrical path conductive.

9. The control device according to claim 4 , wherein the control unit controls the first switch, the second switch, and switching of the communication unit between a transmission mode and a reception mode based on a trigger signal from an external device.

10. further comprising an operation unit that accepts an operation for outputting a trigger signal; The control device according to claim 4 , wherein the control unit controls switching of the first switch, the second switch, and the communication unit between a transmission mode and a reception mode based on the trigger signal from the operation unit.

11. a first connector detachably connected to a second connector connected to the encoder; a detection unit that detects attachment / detachment of the first connector and the second connector, 8. The control device according to claim 1, wherein the control unit controls the first switch based on a detection result of the detection unit.

12. the second connector has a pair of second terminals shorted to each other; The detection unit a pair of first terminals provided in the first connector and detachably connected to the pair of second terminals by connection between the first connector and the second connector; a second power supply connected to one of the pair of first terminals and the signal input section of the control section via a resistor; the other of the pair of first terminals is connected to ground, The control device according to claim 11 , wherein the detection unit changes an input voltage to the signal input unit of the control unit in response to attachment / detachment of the first connector and the second connector.

13. the motor is a three-phase AC motor, an inverter that supplies three-phase AC current to the motor via three power feeders; at least one short-circuiting switch provided in at least one of the three power supply lines, for establishing and interrupting conduction between the provided power supply line and ground; The control device according to claim 9 , wherein the control unit controls the shorting switch based on the trigger signal.

14. A control device according to any one of claims 1 to 5 and 7, the encoder; the motor.