Drive system

Abstract

To further simplify wiring for inputting a signal related to stopping an electric motor to a drive system equipped with a plurality of control units that control an electric motor.SOLUTION: A drive system includes a plurality of control units that control corresponding electric motors according to commands supplied from a host device via a first wiring, a management unit including an input port that receives an input of a first signal related to stopping the electric motor, and a second wiring that connects the management unit and the plurality of control units and that is different from the first wiring. The management unit distributes the first signal input to the input port to each of the plurality of control units via the second wiring.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a drive system. Background Art

[0002] In a drive system for driving a motor, generally, motor control is performed by a driver in accordance with a command from a controller such as a PLC, or motor control is performed based on preset information. In such drive systems, servo drivers that drive multiple axes are also used (see, for example, Patent Documents 1 and 2). Prior Art Literature Patent Literature

[0003] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2005-086918 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2003-169497 Summary of the Invention Problems to be Solved by the Invention

[0004] A servo driver is provided with a safety input port that receives input of a signal related to stopping a servo motor from a safety controller. In recent years, so-called building block type servo systems, in which a plurality of inverter units that control servo motors are connected to a converter unit that supplies current, have also been used. In a building block type servo system, each of the plurality of inverter units is provided with a safety input port, so wiring between the safety controller and each of the plurality of inverter units becomes complicated, which increases the work burden and also carries a risk of incorrect wiring. Such problems can commonly occur in drive systems including servo systems.

[0005] One aspect of the disclosed technology aims to simplify the wiring required to input signals related to stopping an electric motor to a drive system that includes multiple control units that control an electric motor. [Means for solving the problem]

[0006] One aspect of the disclosed technology is exemplified by a drive system, which includes: a plurality of control units that control corresponding electric motors in accordance with commands supplied from a higher-level device via a first wiring; a management unit having an input port that receives input of a first signal relating to the stopping of the electric motors; and a second wiring, different from the first wiring, that connects the management unit to the plurality of control units. The management unit distributes the first signal input to the input port to each of the plurality of control units via the second wiring.

[0007] With the above drive system, if the first signal related to stopping the electric motor is input to the management unit, the management unit can distribute the first signal to multiple control units. In other words, with the above drive system, the first signal can be input to each control unit without having to prepare any wiring other than the second wiring. Therefore, with this drive system, the wiring for inputting the first signal to a drive system equipped with multiple control units can be made simpler.

[0008] In this drive system, the control unit may stop the motor when the first signal is no longer distributed from the management unit. When the first signal is distributed from the control unit, the motor may be stopped. Examples of the first signal related to stopping the motor include a safety signal and an ESTOP signal. The control unit stops the motor when the distribution of the safety signal is stopped. The control unit also stops the motor when the ESTOP signal is distributed. By having the above features, this drive system can stop the motor in response to the safety signal and the ESTOP signal.

[0009] This drive system may have the following features: The control unit synchronizes with the motors associated with other control units to stop the motors corresponding to its own unit. By having these features, this drive system can suitably stop motors even in systems where multiple axes operate in coordination, such as a gantry mechanism. Here, the method of stopping the motors may be any of the following: stopping by free run, stopping by reduction torque, or stopping by driving a braking device.

[0010] The drive system may also have the following features: Each of the multiple control units further includes a second input port that receives a second signal related to stopping the motor. Each of the multiple control units then selects either the first signal distributed from the management unit or the second signal input to the second input port to perform control related to stopping the motor. By having these features, the drive system can be configured to either input the first signal to the management unit or the second signal to the control units, thus increasing the flexibility in constructing the drive system.

[0011] The drive system may have the following features: Among the plurality of control units, a first control unit connected to the management unit by the second wiring and located next to the management unit further includes a detection circuit connected to the second input port for detecting abnormalities in the second input port, and the input port of the management unit and the detection circuit of the first control unit are connected by the second wiring, so that abnormalities in the input port are detected by the detection circuit. By having these features, the drive system can omit the detection circuit for detecting abnormalities in the input port from the management unit, thereby reducing the manufacturing cost of the management unit. [Effects of the Invention]

[0012] According to the disclosed technology, the wiring for inputting signals related to stopping the motor to a drive system equipped with multiple control units that control the motor can be simplified. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows an example of a servo system according to an embodiment. [Figure 2] Figure 2 is a schematic diagram showing the connection between the converter unit and the inverter unit in the servo system according to the embodiment. [Figure 3] Figure 3 shows a first example of a schematic configuration for distributing safety signals supplied from a safety controller in an embodiment. [Figure 4] Figure 4 shows a second example of a schematic configuration for distributing safety signals supplied from a safety controller in an embodiment. [Figure 5] Figure 5 shows a third example of a schematic configuration for distributing safety signals supplied from a safety controller in an embodiment. [Figure 6] Figure 6 is a first diagram illustrating the connection between the safety controller and the control unit in an embodiment. [Figure 7] Figure 7 is a second diagram illustrating the connection between the safety controller and the control unit in an embodiment. [Figure 8] Figure 8 shows an example of a servo system according to the first modified example. [Figure 9] Figure 9 shows a schematic diagram of the self-diagnostic circuit of the servo system in the second modified example. [Modes for carrying out the invention]

[0014] <Embodiment> The servo system according to the embodiment will be described below with reference to the drawings. Figure 1 is a diagram showing an example of the servo system 100 according to the embodiment. The servo system 100 includes a converter unit 1, an inverter unit 2a, an inverter unit 2b, and an inverter unit 2c. A servo motor 3a is connected to inverter unit 2a, a servo motor 3b is connected to inverter unit 2b, and a servo motor 3c is connected to inverter unit 2c. When inverter units 2a, 2b, and 2c are not distinguished, they will also be referred to as inverter unit 2. Similarly, when servo motors 3a, 3b, and 3c are not distinguished, they will also be referred to as servo motor 3. A PLC 5 is connected to the servo system 100 by an industrial network N1. A safety controller 4 is connected to the converter unit 1 of the servo system 100. The safety controller 4 may also be part of the PLC 5 system. The servo system 100 is an example of a "drive system".

[0015] The safety controller 4 is connected to the input port 112 of the converter unit 1 via a safety signal line N2. The safety controller 4 continuously outputs a safety signal to the input port 112 of the converter unit 1 via the safety signal line N2. An emergency stop button 41 is connected to the safety controller 4. When the emergency stop button 41 is pressed, the safety controller 4 stops outputting the safety signal to the converter unit 1. The safety signal is an example of "a signal related to stopping an electric motor".

[0016] The PLC 5 outputs command signals for the converter unit 1 and the inverter unit 2 of the servo system 100 via the industrial network N1. The PLC 5 functions as, for example, a monitoring device for the servo system 100 by executing processing in accordance with a prepared program in advance. The industrial network N1 is, for example, a TCP / IP network. The industrial network N1 is an example of "first wiring".

[0017] The servo system 100 is a building block type servo system including the converter unit 1 and a plurality of inverter units 2. In the servo system 100, it is possible to connect a plurality of inverter units 2 to one converter unit 1, and to disconnect the inverter unit 2 connected to the converter unit 1 from the converter unit 1. In FIG. 1, the servo system 100 includes three inverter units 2, but the number of inverter units 2 may be two or less, or four or more. The servo system 100 is an example of "a servo system".

[0018] Converter unit 1 and inverter unit 2 receive command signals from PLC 5 via industrial network N1. Converter unit 1 is equipped with a safety port 112. Converter unit 1 receives safety signals from safety controller 4 connected to safety port 112. Converter unit 1 also supplies current supplied from a power supply (not shown) to inverter unit 2. The safety signals input to safety port 112 are an example of the "first signal".

[0019] Converter unit 1 distributes the safety signals input from safety controller 4 to inverter units 2a, 2b, and 2c. When the emergency stop button 41 is pressed, the input of safety signals from safety controller 4 to converter unit 1 is stopped. Therefore, the distribution of safety signals from converter unit 1 to inverter units 2a, 2b, and 2c is also stopped. Converter unit 1 is an example of a "management unit".

[0020] The inverter unit 2 receives power from the converter unit 1 and supplies drive current to the servo motor 3. The inverter unit 2 receives feedback signals from the servo motor 3. The inverter unit 2 has a servo system that performs feedback control using a position controller, speed controller, current controller, etc., and uses these signals to servo control and drive the servo motor 3. The inverter unit 2 may be provided with a safety port 223 that receives safety signals from the safety controller 4. The inverter unit 2 stops the servo motor 3 when the distribution of safety signals from the converter unit 1 or the input of safety signals from the safety port 223 stops. The inverter unit 2 is an example of a "control unit". The safety port 223 is an example of a "second input port".

[0021] The servo motor 3 is, for example, an AC servo motor. The servo motor 3 operates by receiving a drive current supplied from the inverter unit 2. The servo motor 3 detects the displacement of its output shaft and outputs a feedback signal indicating the detected displacement to the inverter unit 2. The servo motor 3 is an example of an "electric motor".

[0022] Figure 2 is a schematic diagram showing the connection between the converter unit 1 and the inverter unit 2 in the servo system 100 according to the embodiment. A female other-unit connection port 113 is provided on the side of the converter unit 1. A male upstream connection terminal 221 is provided on the side of the inverter unit 2 that is on the converter unit 1 side (upstream side). A female downstream connection port 222 is provided on the side of the inverter unit 2 that is on the opposite side from the converter unit 1 side (downstream side). The other-unit connection port 113 of the converter unit 1 is connected to the upstream connection terminal 221 of the inverter unit 2a, the downstream connection port 222 of the inverter unit 2a is connected to the upstream connection terminal 221 of the inverter unit 2b, and the downstream connection port 222 of the inverter unit 2b is connected to the upstream connection terminal 221 of the inverter unit 2c. In the servo system 100, the internal signal lines described later are connected by connecting the converter unit 1 and the inverter unit 2 in this way. Once the internal signal wiring is connected, it becomes possible to supply current from converter unit 1 to inverter unit 2 and distribute safety signals.

[0023] Figures 3 to 5 illustrate a schematic configuration for distributing safety signals supplied from the safety controller 4 in an embodiment. Figures 3 to 5 also illustrate a case where safety signals are input to the safety port 223 of the inverter unit 2. The safety signals input to the safety port 223 of the inverter unit 2 may be input from the safety controller 4 by connecting a wire from the safety signal line N2 to the safety port 223, as illustrated in Figure 6. Alternatively, the safety signals input to the safety port 223 of the inverter unit 2 may be input from safety units individually provided for each of the inverter units 2, as illustrated in Figure 7. That is, the safety port 223 of inverter unit 2a and the safety controller 4a may be connected by the safety signal line N2a, the safety port 223 of inverter unit 2b and the safety controller 4b may be connected by the safety signal line N2b, and the safety port 223 of inverter unit 2c and the safety controller 4c may be connected by the safety signal line N2c. Furthermore, each of the inverter units 2 may receive a safety signal input from the safety controller 4 connected to its own safety port 223. In this specification, safety controllers 4, 4a, 4b, and 4c will be referred to simply as safety controller 4 without distinction. The safety signal input to the safety port 223 is an example of a "second signal".

[0024] Figure 3 shows a first example of a schematic configuration for distributing safety signals supplied from a safety controller in an embodiment. The safety signal input to the safety port 112 of the converter unit 1 is distributed to the inverter unit 2 via the internal signal line B2. The inverter unit 2 is provided with a NOR circuit 224 whose inputs are connected to the internal signal line B2 and the safety port 223. The output of the NOR circuit 224 is connected to a motor drive circuit 225 that drives the servo motor 3. When the safety signal is no longer input from either the safety port 112 or the safety port 223, the NOR circuit 224 outputs an emergency stop signal to the motor drive circuit 225. The motor drive circuit 225, upon receiving the emergency stop signal, stops the servo motor 3. The internal signal line B2 is an example of a "second wiring". The internal signal line B2 is not a single common signal line, but may be configured with a circuit in between.

[0025] Figure 4 shows a second example of a schematic configuration for distributing safety signals supplied from a safety controller in an embodiment. In Figure 4, to avoid making the diagram complex, the other unit connection port 113, the upstream connection terminal 221, and the downstream connection port 222 are not shown. In Figure 4, inverter unit 2a is equipped with a control circuit 201a instead of a NOR circuit 224. Inverter unit 2b is equipped with a control circuit 201b instead of a NOR circuit 224. Inverter unit 2c is equipped with a control circuit 201c instead of a NOR circuit 224. When control circuits 201a, 201b, and 201c are not distinguished, they are also referred to as control circuit 201. Control circuit 201 includes a processor and a memory unit, and executes various processes according to the program stored in the memory unit. When the safety signal is no longer input from either safety port 112 or safety port 223, control circuit 201 outputs an emergency stop signal to the motor drive circuit 225. Internal signal line B2 is an example of a "second wiring" configuration. Internal signal line B2 is not a single common signal line; it may be configured to be separated by control circuits 201a, 201b, and 201c.

[0026] Figure 5 shows a third example of a schematic configuration for distributing safety signals supplied from a safety controller in an embodiment. In Figure 5, to avoid making the diagram cluttered, the other unit connection port 113, the upstream connection terminal 221, and the downstream connection port 222 are omitted from the illustration. In the example in Figure 5, the converter unit 1 and the inverter unit 2 are equipped with a control circuit 201. In the converter unit 1, the safety signal input via safety port 112 is input to the control circuit 201. In the inverter unit 2, the safety signal input via safety port 223 is input to the control circuit 201.

[0027] In the example shown in Figure 5, the control circuit 200 of converter unit 1 and the control circuit 201 of inverter unit 2, as well as the control circuits 201 of inverter unit 2 themselves, are connected by an internal signal line B3 between control circuits. The safety signal input to converter unit 1 via safety port 112 is distributed to each of the control circuits 201 of inverter unit 2 via the inter-control circuit signal line B3. Each of the control circuits 201a, 201b, and 201c receives a specification from the user indicating whether to enable the safety signal distributed from converter unit 1 or the safety signal input from safety port 223. Each of the control circuits 201a, 201b, and 201c performs an emergency stop of the servo motor 3 according to the safety signal specified by the user.

[0028] <Effects of the Embodiment> In this embodiment, the safety signal input to the safety port 112 of the converter unit 1 is distributed to the inverter units 2a, 2b, and 2c. Therefore, according to this embodiment, the safety signal is distributed between each of the inverter units 2a, 2b, and 2c and the safety controller 4. Even without the connection via the safety signal line N2, the servo motors 3a, 3b, and 3c connected to the inverter units 2a, 2b, and 2c, respectively, can be stopped in an emergency in response to the safety signal from the safety controller 4. In other words, according to this embodiment, the connection via the safety signal line N2 between the inverter units 2a, 2b, and 2c and the safety controller 4 can be omitted, making the connection between a building block type servo system equipped with multiple inverter units and the safety controller simpler.

[0029] In this embodiment, safety signals are distributed from the converter unit 1 to the inverter units 2a, 2b, and 2c via the internal signal line B2, so the safety port 223 can be omitted from the inverter units 2a, 2b, and 2c. Therefore, according to this embodiment, the configuration of the servo system 100 can be made simpler.

[0030] In this embodiment, the inverter unit 2 may be provided with a safety port 223. By providing the safety port 223 on the inverter unit 2, the inverter unit 2 can directly receive safety signals from the safety controller 4. By adopting this configuration, the inverter unit 2 can receive safety signals distributed from the converter unit 1, or receive safety signals as input from the safety port 223, thus increasing the flexibility of constructing the servo system 100. If the safety port 223 is not provided on the inverter unit 2, the inverter unit 2 does not need to be equipped with a control circuit 200 or a NOR circuit 224.

[0031] <First variation> In this embodiment, the servo motor 3 was emergency stopped when the safety signal input from the safety controller 4 ceased. However, the configuration for emergency stopping the servo motor 3 is not limited to this configuration. In the first modification, a configuration in which an ESTOP signal is input to the converter unit 1 instead of a safety signal will be described.

[0032] Figure 8 shows an example of a servo system 100 according to the first modification. In the first modification, an emergency stop button 41a is connected to the safety port 112 of the converter unit 1 by an ESTOP signal line N3 instead of the safety controller 4.

[0033] When the emergency stop button 41a is pressed, it outputs an ESTOP signal that causes the servo motor 3 to be stopped in an emergency. The ESTOP signal output from the emergency stop button 41a is input to the converter unit 1 via the safety port 112. The converter unit 1 distributes the ESTOP signal input via the safety port 112 to the inverter unit 2 via the internal signal line B2. When the inverter unit 2 receives the ESTOP signal distributed from the converter unit 1, it stops the servo motor 3. The ESTOP signal is an example of a "signal related to stopping an electric motor".

[0034] Here, the servo motor 3 may be stopped, for example, by putting the servo motor 3 into a free-run state in response to a command from the inverter unit 2. Alternatively, the servo motor 3 may be stopped, for example, by applying a deceleration torque to the servo motor 3 in response to a deceleration command from the inverter unit 2. Alternatively, the servo motor 3 may be stopped, for example, by driving a braking device provided on the servo motor 3 in response to a command from the inverter unit 2. Here, the inverter units 2a, 2b, and 2c may each synchronously stop the servo motors 3a, 3b, and 3c, respectively. By stopping the servo motors 3 synchronously, the servo motors 3 can be suitably stopped even in systems where multiple axes operate in coordination, such as a gantry mechanism.

[0035] <Second variation> As described above, when the converter unit 1 is provided with a safety port 112, it is preferable that a self-diagnosis is performed to detect abnormalities in the safety port 112 provided in the converter unit 1. However, while the inverter unit 2 that controls the servo motor 3 is provided with a self-diagnosis circuit, the converter unit 1 that supplies power to the inverter unit 2 is often not provided with a self-diagnosis circuit. If the converter unit 1 is also provided with a self-diagnosis circuit, the configuration of the converter unit 1 becomes complex and also leads to an increase in the cost of the converter unit 1. Therefore, in the second modification, a modification is described in which the self-diagnosis circuit of the converter unit 1 is omitted while self-diagnosis of the safety port 112 is possible.

[0036] Figure 9 shows a schematic diagram of the self-diagnosis circuit of the servo system 100 in the second modified example. In the second modified example, the converter unit 1 does not have a diagnostic circuit for self-diagnosing the safety port 112. The safety port 112 of the converter unit 1 is connected to the other unit connection port 113 via the internal self-diagnosis signal line B4.

[0037] The inverter unit 2 is equipped with a diagnostic circuit 300 that performs self-diagnosis of safety ports 112 and 223. The diagnostic circuit 300 of the inverter unit 2 is connected to the upstream connection terminal 221, the safety port 223, and the downstream connection port 222 of the inverter unit 2. For example, the diagnostic circuit 300 of inverter unit 2a is connected to the upstream connection terminal 221, the safety port 223, and the downstream connection port 222 of inverter unit 2a. The diagnostic circuit 300 is an example of a "detection circuit".

[0038] The safety port 112 of the converter unit 1 is connected to the diagnostic circuit 300 of the inverter unit 2a, which is located next to the converter unit 1, via the internal self-diagnosis signal line B4, the other unit connection port 113, and the upstream connection terminal 221. The inverter unit 2a can perform a self-diagnosis of the safety port 112 of the converter unit 1 via the internal self-diagnosis signal line B4, the other unit connection port 113, and the upstream connection terminal 221. Therefore, according to the second modification, abnormality detection of the safety port 112 of the converter unit 1 can be performed without providing the diagnostic circuit 300 in the converter unit 1. The self-diagnosis of the safety port 223 of the inverter unit 2 can be performed by its own unit's diagnostic circuit 300.

[0039] Even if an abnormality is detected by a function implemented by the converter unit 1, the converter unit 1 may also notify the inverter unit 2a of the abnormality via the internal self-diagnostic signal line B4.

[0040] In the embodiments described above, the servo system 100 includes a converter unit 1 as the management unit and an inverter unit 2 as the control unit, but the servo system 100 may include other configurations. For example, the servo system 100 may include I / O with output functions other than output to the motor as an optional unit, or it may include a unit with combined functions of the converter unit, inverter unit, and optional unit. The management unit may also be an inverter unit, an optional unit, or a combined unit. Similarly, the control unit may also be an inverter unit, an optional unit, or a combined unit.

[0041] The embodiment described above is a so-called servo system in which the servo system 100 is controlled by a PLC 5, but the application of the technology according to this embodiment is not limited to servo systems. The application of the technology according to this embodiment is, for example, to a feed from an encoder. It could be a drive system that does not require feedback control (such as a stepping motor control system), or a so-called inverter system that operates independently without requiring commands from a higher level.

[0042] The embodiments and modifications disclosed above can be combined in any way.

[0043] <Note 1> Multiple control units (2) control the corresponding electric motor (3) according to commands supplied from a higher-level device (5) via a first wiring (N1), A management unit (1) is provided with an input port (112) that receives input of a first signal relating to the stopping of the electric motor, The management unit (1) and the plurality of control units (2) are connected, and a second wiring (B2) different from the first wiring is included, The management unit (1) distributes the first signal input to the input port (112) to each of the multiple control units (2) via the second wiring (B2). Servo system (100). [Explanation of symbols]

[0044] 1. Converter Unit 2. Inverter Unit 2a ··Inverter Unit 2b. Inverter Unit 2c Inverter Unit 3. Servo motor 3a. Servo motor 3b. Servo motor 3c... Servo motor 4. Safety Controller 5··PLC 41. Emergency Stop Button 41a. Emergency stop button 100 Servo System 101...Arithmetic unit 102·Storage device 112 ··Safety Port 113...Other unit connection port 200...control circuit 201...Control circuit 201a Control Circuit 201b...control circuit 201c...control circuit 221 ··Upstream connection terminal 222 ·· Downstream connection port 223 Safety Port 224··NOR circuit 300 diagnostic circuit B1...Interior Bath B2...Internal signal line B3...Internal signal lines between control circuits B4 Self-diagnostic internal signal wire N1 Industrial Network N2 Safety signal wire N2a Safety signal wire N2b Safety signal wire N2c Safety Signal Cable N3...ESTOP signal line

Claims

1. Multiple control units that control corresponding electric motors according to commands supplied from a higher-level device via a first wiring harness, A management unit having a first input port that receives input of a first signal relating to the stopping of the electric motor, The management unit and a second wiring which is internal wiring provided within the housings of the multiple control units, The upstream connection part and the downstream connection part provided on the management unit and each of the plurality of control units are directly connected, thereby connecting the second wiring. The management unit distributes the first signal input to the first input port to each of the multiple control units via the second wiring. Each of the multiple control units is, The system further includes a second input port for receiving a second signal related to the stopping of the electric motor, If neither the first signal nor the second signal is input, control is performed to stop the motor. Of the multiple control units, the first control unit, which is connected to the management unit by the second wiring and positioned next to the management unit, is further equipped with a detection circuit connected to the second input port for detecting abnormalities in the second input port. The first input port of the management unit and the detection circuit of the first control unit are connected by the second wiring, so that abnormality detection of the first input port is performed by the detection circuit. Drive system.

2. The control unit synchronizes with the motors associated with other control units to stop the motors associated with its own unit. The drive system according to claim 1.

3. The control unit stops the motor by allowing it to run free. The drive system according to claim 1 or 2.

4. The control unit stops the motor by applying a reduction torque to it. The drive system according to any one of claims 1 to 3.

5. The control unit stops the electric motor by driving the braking device provided for the electric motor. The drive system according to any one of claims 1 to 3.

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