Communication system and control system

Abstract

To provide a communication system and control system capable of miniaturizing a connection structure.SOLUTION: First wiring 10 connects a control device 300 to a cable 400 and supplies a first power signal from the control device 300 to the cable 400. The first wiring 10 includes first and second nodes 1 and 2. Second wiring 20 connects a drive device 200 to the cable 400 and supplies the first power signal from the cable 400 to the drive device 200. The second wiring 20 includes third and fourth nodes 3 and 4. A power supply part 30 is connected to the first node 1 to supply a second power signal. A power receiving part 40 is connected to the third node 3 to give the second power signal supplied from the power supply part 30 to a detection device 500. A first communication part 50 is connected to the fourth node 4. A second communication part 60 is connected to the second node 2 to transmit or receive a communication signal to or from the first communication part 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to communication and control systems that provide signals. [Background technology]

[0002] In a servo motor system used in a robot or automated equipment, a servo motor and a servo amplifier are connected by a cable, and power is supplied from the servo amplifier to the servo motor via the cable. The servo motor is also equipped with various devices for detecting the operating state of the servo motor, and these devices are connected to the servo amplifier by multiple wires. Therefore, the connection structure between the servo motor and the servo amplifier tends to be large.

[0003] For example, Patent Document 1 describes a control device in which a temperature detector and an encoder device are provided on a motor. The encoder device is connected to a control circuit by a pair of DC power supply lines and three pairs of output signal lines. DC power is supplied from the control circuit to the encoder device via the pair of DC power supply lines. A pulse signal indicating the rotation speed of the motor is output from the encoder device to the control circuit via the three pairs of output signal lines. In addition, a signal detected by the temperature detector in accordance with the temperature of the motor is output as a DC signal to the control circuit via the pair of DC power supply lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-149899 Summary of the Invention [Problem to be solved by the invention]

[0005] In the control device described in Patent Document 1, there is no need to provide a dedicated signal line for outputting the signal detected by the temperature detector to the control circuit. This reduces the need for a large connection structure. However, in servo motor systems and the like, there is a demand for even smaller connection structures.

[0006] An object of the present invention is to provide a communication system and a control system that can reduce the size of the connection structure. [Means for solving the problem]

[0007] A communication system according to one aspect of the present invention is a communication system provided between a drive device and a control device that controls the operation of the drive device through a cable based on the operating state of the drive device detected by a detection device, and includes: a first wiring that connects the control device to the cable and has a first node and a second node, and supplies a first power signal from the control device to the cable; a second wiring that connects the drive device to the cable and has a third node and a fourth node, and supplies the first power signal from the cable to the drive device; a power supply unit connected to the first node of the first wiring and supplies a second power signal; a power receiving unit connected to the third node of the second wiring and supplies the second power signal supplied from the power supply unit to the detection device; a first communication unit connected to the fourth node of the second wiring; and a second communication unit connected to the second node of the first wiring and transmitting or receiving a communication signal indicating arbitrary information between the first communication unit and the first communication unit.

[0008] A control system according to another aspect of the present invention includes a cable, a drive device, a detection device that detects the operating state of the drive device, a control device that controls the operation of the drive device through the cable based on the operating state of the drive device detected by the detection device, and the above-mentioned communication system provided between the drive device and the control device. [Effects of the Invention]

[0009] According to the present invention, the connection structure in a communication system can be made smaller. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a configuration of a control system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram illustrating a cable configuration. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a power supply unit. [Figure 4] FIG. 10 is a diagram illustrating another example of the configuration of the power supply unit. [Figure 5] FIG. 2 is a diagram illustrating a configuration of a power receiving unit. [Figure 6] FIG. 10 is a diagram illustrating a configuration of a composite filter. [Figure 7] FIG. 1 is a diagram illustrating a configuration of a band-pass filter. [Figure 8] 3A and 3B are diagrams illustrating frequency characteristics of various signals and various filters. [Figure 9] FIG. 2 is a diagram illustrating a transmission path of a drive signal. [Figure 10] FIG. 2 is a diagram illustrating a transmission path of a power supply signal. [Figure 11] FIG. 2 is a diagram illustrating a transmission path of a communication signal. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. Control system configuration A communication system and a control system according to an embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a control system according to an embodiment of the present invention. As shown in FIG. 1, a control system 600 includes a communication system 100, a driving device 200, a control device 300, a cable 400, and a detection device 500. The communication system 100 is provided between the driving device 200 and the control device 300.

[0012] In this example, the control system 600 is a servo motor system including a servo motor 610, a servo amplifier 620, and a command device 630. The driving device 200 and the detection device 500 are provided as parts of the servo motor 610. The driving device 200 is the motor body. The detection device 500 includes, for example, an encoder, and is attached to the rotating shaft of the driving device 200. The detection device 500 may be provided integrally as a detection unit of the driving device 200. The detection device 500 detects the rotation speed or rotation angle of the rotating shaft of the driving device 200 as the operating state of the driving device 200.

[0013] The control device 300 includes, for example, a CPU (Central Processing Unit) and a power supply, and is provided as part of the servo amplifier 620. The control device 300 controls the operation of the drive device 200 based on commands given from the command device 630 and / or the operating state of the drive device 200. The command device 630 includes, for example, a CPU. The command device 630 commands the control device 300 to output a drive signal, which will be described later, mainly when the drive device 200 starts operating.

[0014] The communication system 100 includes a wiring 10, a wiring 20, a power supply unit 30, a power receiving unit 40, a communication unit 50, a communication unit 60, a pair of composite filters 70, a pair of band-pass filters 80, and a pair of high-pass filters 90. The power receiving unit 40 and the communication unit 50 may be provided as part of a servo motor 610. The power supply unit 30 and the communication unit 60 may be provided as part of a servo amplifier 620. The communication units 50 and 60 are capable of communicating with each other.

[0015] The wiring 10 connects the control device 300 to one end of the cable 400. Nodes 1 and 2 are provided on the wiring 10. In the example of FIG. 1, nodes 1 and 2 are provided in this order from left to right on the page, but the order of nodes 1 and 2 is not limited. Furthermore, power from the control device 300 is supplied to the cable 400 via the wiring 10 as a drive signal. The drive signal is an example of a first power signal.

[0016] The wiring 20 connects the driving device 200 to the other end of the cable 400. Nodes 3 and 4 are provided on the wiring 20. In the example of FIG. 1, the nodes 3 and 4 are provided in this order from right to left on the page, but the order of the nodes 3 and 4 is not limited thereto. A driving signal from the cable 400 is supplied to the driving device 200 via the wiring 20. The driving device 200 is driven by the supply of the driving signal. Therefore, when driving of the driving device 200 is to be stopped, the supply of the driving signal is stopped.

[0017] The power supply unit 30 is connected to node 1 of the wiring 10 and supplies power as a power supply signal. The power supply signal is an example of a second power signal. The power receiving unit 40 is connected to node 3 of the wiring 20. As a result, the power supply signal from the power supply unit 30 is supplied to the power receiving unit 40. The power receiving unit 40 receives the power supply signal and supplies power to the communication unit 50 and the detection device 500. As a result, the communication unit 50 and the detection device 500 operate. The operating state of the drive device 200 is detected by the detection device 500 not only while the drive device 200 is operating, but also while it is stopped. Therefore, the power supply signal needs to be supplied before the drive signal.

[0018] The communication unit 50 is connected to a node 4 of the wiring 20. The communication unit 50 includes, for example, a PLC (Power Line Communication) modem, and outputs a communication signal indicating the operating state of the drive device 200 detected by the detection device 500. The communication unit 60 is connected to a node 2 of the wiring 10. The communication unit 60 includes, for example, a PLC modem, and acquires the communication signal output by the communication unit 50 and provides it to the control device 300. Note that, like the communication unit 50, the communication unit 60 is also supplied with power, but the form in which power is supplied to the communication unit 60 is not particularly limited.

[0019] When the control device 300 instructs the detection device 500 to detect the operating state, the communication unit 60 may output a detection instruction signal instructing the detection. In this case, the communication unit 50 acquires the detection instruction signal output by the communication unit 60 and provides it to the communication unit 50. As a result, the operating state of the drive device 200 is detected by the detection device 500.

[0020] Of the pair of composite filters 70, one composite filter 70 is provided on the wiring 10, and the other composite filter 70 is provided on the wiring 20. Here, nodes 1 and 2 on the wiring 10 are located between one composite filter 70 and the cable 400. Also, nodes 3 and 4 on the wiring 20 are located between the other composite filter 70 and the cable 400. Each composite filter 70 consists of a band-elimination filter and a low-pass filter.

[0021] Of the pair of band-pass filters 80, one band-pass filter 80 is provided between node 1 of wiring 10 and power supply unit 30, and the other band-pass filter 80 is provided between node 3 of wiring 20 and power receiving unit 40. Of the pair of high-pass filters 90, one high-pass filter 90 is provided between node 4 of wiring 20 and communication unit 50, and the other high-pass filter 90 is provided between node 2 of wiring 10 and communication unit 60.

[0022] The composite filter 70 provided in the wiring 20, the band-pass filter 80 between the node 3 and the power receiving unit 40, and the high-pass filter 90 between the node 4 and the communication unit 50 may be provided as part of the servo motor 610. The composite filter 70 provided in the wiring 10, the band-pass filter 80 between the node 1 and the power supply unit 30, and the high-pass filter 90 between the node 2 and the communication unit 60 may be provided as part of the servo amplifier 620.

[0023] 2. Three-phase cable Fig. 2 is a diagram showing the configuration of cable 400. As shown in Fig. 2, in this embodiment, cable 400 is a three-phase cable including wires 410, 420, and 430. Communication system 100 includes three wires 10 and three wires 20. When distinguishing between the three wires 10, the three wires 10 are referred to as wires 11, 12, and 13, respectively. When distinguishing between the three wires 20, the three wires 20 are referred to as wires 21, 22, and 23, respectively.

[0024] The control device 300 is connected to one end of the wirings 410, 420, and 430 by wirings 11, 12, and 13, respectively. The driving device 200 is connected to the other end of the wirings 410, 420, and 430 by wirings 21, 22, and 23, respectively. The nodes 1 and 3 are provided on wirings 10 and 20, respectively, which are connected to one or more common wirings among the wirings 410, 420, and 430. Similarly, the nodes 2 and 4 are provided on wirings 10 and 20, respectively, which are connected to one or more common wirings among the wirings 410, 420, and 430.

[0025] In this example, node 1 is provided on each of the wirings 11 to 13. Node 3 is provided on each of the wirings 21 to 23. Node 2 is provided on each of the wirings 11 and 12. Node 4 is provided on each of the wirings 21 and 22. A composite filter 70 is provided on each of the wirings 11 to 13, and a composite filter 70 is provided on each of the wirings 21 to 23. A band-pass filter 80 is provided between the power supply unit 30 and each node 1, and a band-pass filter 80 is provided between the power receiving unit 40 and each node 3. A high-pass filter 90 is provided between the communication unit 50 and the two nodes 4, and a high-pass filter 90 is provided between the communication unit 60 and the two nodes 2.

[0026] Power supplying unit 30 supplies power supply signals having phases that differ by 120 degrees to wiring 11 to 13, respectively. FIG. 3 is a diagram showing an example of the configuration of power supplying unit 30. As shown in FIG. 3, power supplying unit 30 includes an internal power supply 31 and a signal generating unit 32, and is connected to an external power supply. The external power supply is, for example, a DC power supply, and supplies DC power. Internal power supply 31 provides power supplied from the external power supply to signal generating unit 32. Signal generating unit 32 receives power from internal power supply 31 and generates a power supply signal.

[0027] FIG. 4 is a diagram showing another example of the configuration of the power supply unit 30. As shown in FIG. 4, the power supply unit 30 may further include a transformer 33. The transformer 33 includes a primary coil La and a secondary coil Lb that are electrically insulated from each other and magnetically coupled to each other. The primary coil La is connected to an external power supply 640. The secondary coil Lb is connected to an internal power supply 31. Therefore, the external power supply 640 and the internal power supply 31 are electrically insulated from each other. The transformer 33 may be built into the internal power supply 31. The transformer 33 transforms DC power from the external power supply 640 and supplies it to the internal power supply 31. The internal power supply 31 converts the supplied DC power to a predetermined magnitude and provides it to the signal generating unit 32.

[0028] The signal generating unit 32 is configured by, for example, an electric circuit. The signal generating unit 32 receives DC power from the internal power supply 31 and generates three sinusoidal power supply signals that are different in phase by 120 degrees. The three power supply signals generated by the signal generating unit 32 are supplied to the wirings 11 to 13 via band-pass filters 80, respectively. In each of the wirings 11 to 13, the supplied power supply signal is superimposed on a drive signal.

[0029] 5 is a diagram showing the configuration of power receiving unit 40. As shown in FIG. 5, power receiving unit 40 includes rectifier unit 41 and power supply unit 42. Rectifier unit 41 includes, for example, rectifying elements connected in a bridge configuration. Rectifier unit 41 acquires power supply signals from wirings 11 to 13 and rectifies the acquired power supply signals to generate DC power. Power supply unit 42 converts the DC power generated by rectifier unit 41 to a predetermined magnitude and supplies it to detection device 500 and communication unit 50 in FIG. 2.

[0030] 3. Frequency characteristics The frequency characteristics of various filters and various signals will be described below. Fig. 6 is a diagram showing the configuration of a composite filter 70. As shown in Fig. 6, in the composite filter 70, a band-elimination filter 71 and a low-pass filter 72 are connected in series. The band-elimination filter 71 has a configuration in which a coil L1 and a capacitor C1 are connected in parallel. The low-pass filter 72 is formed by a coil L0. Fig. 7 is a diagram showing the configuration of a band-pass filter 80. As shown in Fig. 7, the band-pass filter 80 has a configuration in which a coil L2 and a capacitor C2 are connected in series.

[0031] FIG. 8 is a diagram showing the frequency characteristics of various signals and various filters. The upper part of FIG. 8 shows a graph illustrating the relationship between the frequency and intensity of various signals. The lower part of FIG. 8 shows a graph illustrating the relationship between the frequency and pass gain of various filters. Note that the frequency characteristics of the band-elimination filter 71 in the lower part of FIG. 8 are shown by a dashed line for ease of visualization. As shown in the upper part of FIG. 8, the drive signal, power supply signal, and communication signal have peak frequencies f1, f2, and f3, respectively. The peak frequencies f1 to f3 are different from one another. In this example, the peak frequency f2 is higher than the peak frequency f1 and lower than the peak frequency f3.

[0032] As shown in the lower part of Figure 8, the band-elimination filter 71 of the composite filter 70 has a cutoff frequency fa. Therefore, the band-elimination filter 71 eliminates signals having frequencies near the cutoff frequency fa. The low-pass filter 72 of the composite filter 70 has a cutoff frequency fb. Therefore, the low-pass filter 72 passes signals having frequencies equal to or less than the cutoff frequency fb and attenuates signals having frequencies greater than the cutoff frequency fb.

[0033] The band-pass filter 80 has a cutoff frequency fc. Therefore, the band-pass filter 80 passes signals having frequencies near the cutoff frequency fc. The high-pass filter 90 has a cutoff frequency fd. Therefore, the high-pass filter 90 passes signals having frequencies equal to or greater than the cutoff frequency fd and attenuates signals having frequencies lower than the cutoff frequency fd.

[0034] Each of cutoff frequencies fa and fc is set to peak frequency f2. Cutoff frequency fb is set to a frequency between peak frequency f1 and peak frequency f3. In this example, cutoff frequency fb is set to a frequency between peak frequency f1 and peak frequency f2. Cutoff frequency fd is set to a frequency between peak frequency f2 and peak frequency f3. In this example, peak frequency f1 is several tens of kHz, peak frequency f2 is several MHz, and peak frequency f3 is several tens of MHz.

[0035] The values ​​of the peak frequencies f1 to f3 are not limited to the above example, but the peak frequency f2 may be 300 kHz or more and 30 MHz or less. In this case, it is easy to configure a band-elimination filter 71 having a cutoff frequency fa that matches the peak frequency f2. Similarly, it is easy to configure a band-pass filter 80 having a cutoff frequency fc that matches the peak frequency f2. The cutoff frequency fa is a resonant frequency determined by the inductance of the coil L1 and the capacitance of the capacitor C1 in FIG. 6. The cutoff frequency fc is a resonant frequency determined by the inductance of the coil L2 and the capacitance of the capacitor C2 in FIG. 7.

[0036] 4. Control System Operation FIG. 9 is a diagram showing the transmission path of the drive signal. As shown in FIG. 9, the control device 300 outputs a drive signal based on the operating state of the drive device 200 indicated by a command signal provided by the command device 630 and / or a communication signal provided by the communication unit 60. The peak frequency f1 of the drive signal does not match the cutoff frequency fa of the band-elimination filter 71 of each composite filter 70 and is lower than the cutoff frequency fb of the low-pass filter 72. Therefore, the drive signal output by the control device 300 passes through the pair of composite filters 70 and is provided to the drive device 200. This drives the drive device 200.

[0037] On the other hand, the peak frequency f1 of the drive signal does not match the cutoff frequency fc of each band-pass filter 80. Therefore, the drive signal output by the control device 300 hardly passes through each band-pass filter 80, and is not supplied to the power supply unit 30 and the power receiving unit 40, as indicated by the crosses in FIG. 9. Furthermore, the peak frequency f1 of the drive signal is lower than the cutoff frequency fd of each high-pass filter 90. Therefore, the drive signal output by the control device 300 hardly passes through each high-pass filter 90, and is not supplied to the communication units 50 and 60, as indicated by the crosses in FIG. 9.

[0038] FIG. 10 is a diagram showing a transmission path of a power supply signal. As shown in FIG. 10, the power supply unit 30 outputs a power supply signal. The peak frequency f2 of the power supply signal matches the cutoff frequency fc of each band-pass filter 80. Therefore, the power supply signal output by the power supply unit 30 passes through the pair of band-pass filters 80 and is provided to the power receiving unit 40. This activates the detection device 500 and the communication unit 50. As a result, the operating state of the drive device 200 is detected by the detection device 500. Furthermore, a communication signal is output from the communication unit 50 based on the detection result.

[0039] On the other hand, the peak frequency f2 of the power feed signal coincides with the cutoff frequency fa of the band-elimination filter 71 of each composite filter 70. Therefore, the power feed signal output by the power supply unit 30 hardly passes through the band-elimination filter 71 of each composite filter 70, and is not supplied to the driving device 200 and the control device 300, as indicated by the crosses in FIG. 10. Furthermore, the peak frequency f2 of the power feed signal is lower than the cutoff frequency fd of each high-pass filter 90. Therefore, the power feed signal output by the power supply unit 30 hardly passes through the high-pass filter 90, and is not supplied to the communication units 50 and 60, as indicated by the crosses in FIG. 10.

[0040] 11 is a diagram showing a transmission path of a communication signal. As shown in FIG. 11, the communication unit 50 outputs a communication signal based on the detection result of the operating state of the drive unit 200 by the detection device 500. The peak frequency f3 of the communication signal is higher than the cutoff frequency fd of each high-pass filter 90. Therefore, the communication signal output by the communication unit 50 passes through the pair of high-pass filters 90 and is provided to the communication unit 60. As a result, the communication signal is provided from the communication unit 60 to the control device 300.

[0041] On the other hand, the peak frequency f3 of the communication signal is higher than the cutoff frequency fb of the low-pass filter 72 of each composite filter 70. Therefore, the communication signal output by the communication unit 50 hardly passes through the low-pass filter 72 of each composite filter 70, and is not supplied to the drive unit 200 and the control unit 300, as indicated by the cross marks in FIG. 11. Furthermore, the peak frequency f3 of the communication signal does not match the cutoff frequency fc of each band-pass filter 80. Therefore, the communication signal output by the communication unit 50 hardly passes through the band-pass filter 80, and is not supplied to the power supply unit 30 and the power receiving unit 40, as indicated by the cross marks in FIG.

[0042] 5.Effects In communication system 100 according to this embodiment, control device 300 and cable 400 are connected by wiring 10, and a drive signal from control device 300 is supplied to cable 400 via wiring 10. Driving device 200 and cable 400 are connected by wiring 20, and a drive signal from cable 400 is supplied to driving device 200 via wiring 20. This drives driving device 200.

[0043] Nodes 1 and 2 are provided on wiring 10. Nodes 3 and 4 are provided on wiring 20. A power supply signal is supplied from power supply unit 30 connected to node 1 of wiring 10. The power supply signal is supplied from power supply unit 30 to power receiving unit 40 connected to node 3 of wiring 20. This activates detection device 500 and communication unit 50. Therefore, the operating state of drive device 200 is detected by detection device 500.

[0044] A communication signal indicating the operating state of the drive device 200 detected by the detection device 500 is output by a communication unit 50 connected to node 4 of the wiring 20. The communication signal output by the communication unit 50 is acquired by a communication unit 60 connected to node 2 of the wiring 10. The communication signal acquired by the communication unit 60 is provided to the control device 300. As a result, the operation of the drive device 200 is controlled by the control device 300 based on the operating state of the drive device 200.

[0045] According to this configuration, in control system 600 in which drive device 200, detection device 500, power receiving unit 40, and communication unit 50 are arranged apart from control device 300, power supply unit 30, and communication unit 60, there is no need to provide dedicated wiring for connecting power receiving unit 40 and power supply unit 30. In addition, there is no need to provide dedicated wiring for connecting communication unit 50 and communication unit 60. Therefore, the connection structure in communication system 100 can be made smaller.

[0046] The drive signal, power supply signal, and communication signal each have peak frequencies f1 to f3. The peak frequencies f1 to f3 are different from one another. In this case, the drive signal, power supply signal, and communication signal can be easily separated. In particular, in this example, peak frequency f2 is higher than peak frequency f1 and lower than peak frequency f3. In this case, the drive signal, power supply signal, and communication signal can be more easily separated. Furthermore, by setting peak frequency f2 between peak frequencies f1 and f3, the composite filter 70, band-pass filter 80, and high-pass filter 90 can each be configured using inexpensive and compact coils or capacitors, etc.

[0047] Specifically, a composite filter 70 consisting of a band-elimination filter 71 and a low-pass filter 72 is provided on each of the wirings 10 and 20. In this case, the drive signal can be separated from the power supply signal and the communication signal with a simple configuration. The cutoff frequency fa of the band-elimination filter 71 is the peak frequency f2, and the cutoff frequency fb of the low-pass filter 72 is between the peak frequencies f1 and f3. In this case, it is possible to supply a drive signal from the control device 300 to the drive device 200, while preventing the power supply signal and the communication signal from being supplied to the drive device 200 and the control device 300.

[0048] Furthermore, band-pass filters 80 are provided between node 1 of wiring 10 and power supply unit 30, and between node 3 of wiring 20 and power receiving unit 40. In this case, the power supply signal can be separated from the drive signal and the communication signal with a simple configuration. The cutoff frequency fc of band-pass filter 80 is peak frequency f2. In this case, it is possible to supply the power supply signal from power supply unit 30 to power receiving unit 40, while preventing the drive signal and the communication signal from being supplied to power supply unit 30 and power receiving unit 40.

[0049] Furthermore, a high-pass filter 90 is provided between node 4 of wiring 20 and communication unit 50, and between node 2 of wiring 10 and communication unit 60. In this case, the communication signal can be separated from the drive signal and power supply signal with a simple configuration. The cutoff frequency fd of the high-pass filter 90 is between peak frequencies f2 and f3. In this case, it is possible to supply the communication signal from communication unit 50 to communication unit 60, while preventing the drive signal and power supply signal from being supplied to communication unit 50 and communication unit 60.

[0050] Cable 400 is a three-phase cable including three wires 410, 420, and 430. Nodes 1 and 3 are provided on wires 10 and 20, respectively, which are connected to one or more common wires among wires 410, 420, and 430. Nodes 2 and 4 are provided on wires 10 and 20, respectively, which are connected to one or more common wires among wires 410, 420, and 430.

[0051] In this case, not only the drive signal but also the power supply signal and the communication signal can be supplied using a three-phase cable. In this example, nodes 1 and 3 are provided on each of the three wirings 10 (wirings 11 to 13). The power supply unit 30 supplies power supply signals to the wirings 11 to 13, each of which has a phase difference of 120 degrees. With this configuration, the power supply signals are supplied via the wirings 11 to 13, so that a large amount of power can be supplied even if the amplitude of the power supply signal to each of the wirings 11 to 13 is small.

[0052] In the power supply unit 30, the internal power supply 31 and the external power supply 640 are electrically insulated. Power supplied from the external power supply 640 is provided to the signal generation unit 32 by the internal power supply 31. A power feed signal is generated by supplying power to the signal generation unit 32. With this configuration, even if there is variation in the elements constituting the signal generation unit 32, it is possible to eliminate common mode current in each wiring due to phase fluctuations of the power feed signal. This makes it possible to reduce common mode noise in the power feed signal.

[0053] In power receiving unit 40, rectifier 41 rectifies the power supply signal to generate DC power, which is then provided to power supply unit 42. Power supply unit 42 converts the DC power generated by rectifier 41 to a predetermined magnitude and provides it to detection device 500 and communication unit 50. This causes detection device 500 to operate, and the operating state of drive device 200 is detected.

[0054] 6. Other Embodiments (1) In the above embodiment, node 1 is provided on each of wires 11 to 13, and node 3 is provided on each of wires 21 to 23, but the embodiment is not limited to this. Nodes 1 and 2 may be provided on wires 10 and 20, respectively, which are connected to two common wires among wires 410, 420, and 430 of the three-phase cable. Furthermore, power supply unit 30 may supply feed signals with phases that differ by 180 degrees to the two common wires. With this configuration, the feed signal is supplied via two of wires 11 to 13, so that a relatively large amount of power can be supplied even if the amplitude of the feed signal to each wire is small.

[0055] Furthermore, when the power consumption of power receiving unit 40 is small, there is no need to supply a large amount of power to power receiving unit 40. Therefore, nodes 1 and 3 may be provided on wiring 10 and wiring 20, respectively, which are connected to one common wiring among wirings 410, 420, and 430 of the three-phase cable, and a power supply signal may be supplied from power supply unit 30 to power receiving unit 40 through these wirings 10 and 20.

[0056] (2) In the above embodiment, the composite filter 70 includes the band-elimination filter 71, but the embodiment is not limited to this. If the power supply signal hardly passes through the low-pass filter 72, the composite filter 70 does not need to include the band-elimination filter 71. In other words, the low-pass filter 72 may be provided instead of the composite filter 70.

[0057] Furthermore, in the above embodiment, a band-pass filter having a cutoff frequency near the peak frequency of the communication signal may be provided instead of the high-pass filter 90. Even in this case, it is possible to prevent the drive signal and power supply signal from being supplied to the communication unit 50 and the communication unit 60 while still allowing the communication signal to be supplied from the communication unit 50 to the communication unit 60.

[0058] (3) In the above embodiment, the cable 400 is a three-phase cable, but the embodiment is not limited to this. The cable 400 may be a two-phase cable or a single-phase cable.

[0059] (4) In the above embodiment, the control system 600 is a servo motor system, but the embodiment is not limited to this. The control system 600 may be another system including the drive unit 200 and the control unit 300. For example, the control system 600 may be an Ethernet communication system. Alternatively, the control system 600 may be a system that does not include the drive unit 200 and the control unit 300.

[0060] (5) The functions of the above-disclosed elements may be implemented using circuitry or processing circuitry, including general-purpose processors, special-purpose processors, integrated circuits, ASICs (application-specific integrated circuits), conventional circuitry, and / or combinations thereof, configured to perform the disclosed elements or programmed to perform the disclosed functions. A processor is considered processing circuitry or circuitry when it includes transistors and other circuitry therein. In this disclosure, a circuitry, unit, or means is hardware that performs the recited function or hardware programmed to perform the function. The hardware may be any hardware disclosed herein or other known hardware programmed to perform or configured to perform the recited function. When the hardware is a processor, which may be considered a type of circuitry, the circuitry, means, or unit is a combination of hardware and software, software used to configure the hardware, and / or processor.

[0061] 7. Correspondence between each element of the claims and each part of the embodiment Below, examples of correspondence between each element of the claims and each element of the embodiments will be described, but the present invention is not limited to the following examples. Various other elements having the configuration or function described in the claims can also be used as each element of the claims.

[0062] In the above-described embodiment, driving device 200 is an example of a driving device, detecting device 500 is an example of a detecting device, cable 400 is an example of a cable, control device 300 is an example of a control device, communication system 100 is an example of a communication system, and nodes 1 to 4 are examples of first to fourth nodes, respectively. Wiring 10 to 13 are examples of first wiring, wiring 20 to 23 are examples of second wiring, power supply unit 30 is an example of a power supply unit, power receiving unit 40 is an example of a power receiving unit, and communication units 50 and 60 are examples of first and second communication units, respectively.

[0063] Peak frequencies f1 to f3 are examples of first to third peak frequencies, band-elimination filter 71 is an example of a band-elimination filter, and low-pass filter 72 is an example of a low-pass filter. Composite filter 70 is an example of a composite filter, cutoff frequencies fa to fd are examples of first to fourth cutoff frequencies, and band-pass filter 80 is an example of a band-pass filter. High-pass filter 90 is an example of a high-pass filter, wiring 410, 420, and 430 are examples of wiring, signal generation unit 32 is an example of a signal generation unit, internal power supply 31 is an example of an internal power supply, rectification unit 41 is an example of a rectification unit, power supply unit 42 is an example of a power supply unit, and control system 600 is an example of a control system.

[0064] 8. Summary of the embodiment (1) The communication system according to paragraph 1 is A communication system provided between a drive device and a control device that controls operation of the drive device through a cable based on an operating state of the drive device detected by a detection device, a first wiring that connects the control device and the cable, has a first node and a second node, and supplies a first power signal from the control device to the cable; a second wiring that connects the drive device and the cable, has a third node and a fourth node, and supplies the first power signal from the cable to the drive device; a power supply unit connected to the first node of the first wiring and supplying a second power signal; a power receiving unit connected to the third node of the second wiring and configured to provide the second power signal supplied from the power supply unit to the detection device; a first communication unit connected to the fourth node of the second wiring; and a second communication unit connected to the second node of the first wiring and transmitting or receiving a communication signal indicating any information to or from the first communication unit.

[0065] According to this communication system, in a control system in which the drive device, power receiving unit, and first communication unit are disposed apart from the control device, detection device, power supply unit, and second communication unit, there is no need to provide dedicated wiring for connecting the power receiving unit and the power supply unit. Also, there is no need to provide dedicated wiring for connecting the first communication unit and the second communication unit. Therefore, the connection structure in the communication system can be made smaller.

[0066] (2) In the communication system according to (1), the first power signal has a first peak frequency; the second power signal has a second peak frequency; the communication signal has a third peak frequency; The first peak frequency, the second peak frequency and the third peak frequency may be different from each other.

[0067] In this case, the first power signal, the second power signal, and the communication signal can be easily separated.

[0068] (Item 3) In the communication system according to item 2, The second peak frequency may be higher than the first peak frequency and lower than the third peak frequency.

[0069] In this case, the first power signal, the second power signal, and the communication signal can be more easily separated.

[0070] (4) The communication system according to the third aspect of the present invention is The signal processing device may further include a composite filter provided on each of the first wiring and the second wiring, the composite filter including a band-elimination filter and a low-pass filter.

[0071] In this case, the first power signal can be separated from the second power signal and the communication signal with a simple configuration.

[0072] (5) In the communication system according to the fourth aspect, A first cutoff frequency of the band-stop filter of the composite filter may be the second peak frequency.

[0073] In this case, it is possible to prevent the second power signal from being supplied to the drive device and the control device, while allowing the control device to supply the first power signal to the drive device.

[0074] (Item 6) In the communication system according to item 4 or 5, A second cutoff frequency of the low pass filter of the composite filter may be between the first peak frequency and the third peak frequency.

[0075] In this case, it is possible to prevent a communication signal from being supplied to the drive device and the control device while allowing the control device to supply the first power signal to the drive device.

[0076] (7) The communication system according to any one of paragraphs 3 to 6, The power supply device may further include a band-pass filter provided between the first node of the first wiring and the power supply unit, and between the third node of the second wiring and the power receiving unit.

[0077] In this case, the second power signal can be separated from the first power signal and the communication signal with a simple configuration.

[0078] (Item 8) In the communication system according to item 7, A third cutoff frequency of the bandpass filter may be the second peak frequency.

[0079] In this case, it is possible to prevent the first power signal and the communication signal from being supplied to the power supply unit and the power receiving unit, while allowing the second power signal to be supplied from the power supply unit to the power receiving unit.

[0080] (Item 9) The communication system according to any one of items 3 to 8, The device may further include a high-pass filter provided between the fourth node of the second wiring and the first communication unit, and between the second node of the first wiring and the second communication unit.

[0081] In this case, the communication signal can be separated from the first power signal and the second power signal with a simple configuration.

[0082] (Item 10) In the communication system according to item 9, A fourth cutoff frequency of the high-pass filter may be between the second peak frequency and the third peak frequency.

[0083] In this case, it is possible to prevent the first power signal and the second power signal from being supplied to the first communication unit and the second communication unit while enabling the supply of a communication signal from the first communication unit to the second communication unit.

[0084] (Item 11) In the communication system according to any one of items 1 to 10, the cable is a three-phase cable containing three wires; the control device is connected to the three wirings of the three-phase cable by three of the first wirings, respectively; the drive device is connected to the three wirings of the three-phase cable by three of the second wirings, respectively; the first node and the third node are provided on the first wiring and the second wiring, respectively, which are connected to one or more common wirings among the three wirings of the three-phase cable; The second node and the fourth node may be provided on the first wiring and the second wiring, respectively, which are connected to one or more common wirings among the three wirings of the three-phase cable.

[0085] In this case, a three-phase cable can be used to supply not only the first power signal, but also the second power signal and the communication signal.

[0086] (12) In the communication system according to claim 11, the first nodes are provided on the three first wirings, respectively; the third node is provided on each of the three second wirings, The power supply unit may supply the second power signals to the three first wirings, the second power signals being different in phase by 120 degrees each.

[0087] According to this configuration, the second power signal is supplied via the three wires of the three-phase cable, so that even if the amplitude of the second power signal to each wire is small, a large amount of power can be supplied.

[0088] (13) In the communication system according to claim 11, the first node is provided on each of two of the first wirings connected to two of the three wirings of the three-phase cable, the third node is provided on each of the two second wirings connected to the two wirings of the three-phase cable, respectively; The power supply unit may supply the second power signals to the two first wirings, the second power signals being out of phase with each other by 180 degrees.

[0089] According to this configuration, the second power signal is supplied via two of the three wires of the three-phase cable, so that a relatively large amount of power can be supplied even if the amplitude of the second power signal to each wire is small.

[0090] (14) In the communication system according to either of paragraphs 12 or 13, The power supply unit a signal generating unit that receives a supply of power and generates the second power signal; The power supply may include an internal power supply that is electrically insulated from an external power supply and supplies power supplied from the external power supply to the signal generating unit.

[0091] This configuration can eliminate common-mode currents in the wiring due to phase fluctuations of the second power signal even when there is variation in the elements that make up the signal generating unit, thereby reducing common-mode noise in the second power signal.

[0092] (Item 15) In the communication system according to any one of items 1 to 14, The power receiving unit is a rectification unit that rectifies the second power signal to generate DC power; The power supply may include a power supply unit that supplies the DC power generated by the rectifier unit to the detection device and the first communication unit.

[0093] In this case, the second power signal can be used to operate the detection device and the first communication unit.

[0094] (16) The control system according to the 16th paragraph is Cable and A drive unit; a detection device for detecting an operating state of the drive device; a control device that controls the operation of the drive device through the cable based on the operating state of the drive device detected by the detection device; The communication system according to any one of paragraphs 1 to 15 is provided between the drive device and the control device.

[0095] According to this control system, the above-mentioned communication system is provided between the drive device and the control device, so that the connection structure in the control system can be made compact. [Explanation of symbols]

[0096] 1-4...nodes, 10-13, 20-23, 410, 420, 430...wiring, 30...power supply unit, 31...internal power supply, 32...signal generation unit, 33...transformer, 40...power receiving unit, 41...rectification unit, 42...power supply unit, 50, 60...communication unit, 70...composite filter, 71...band elimination filter, 72...low-pass filter, 80...band-pass filter, 90...high-pass filter, 100...communication system, 200...drive unit, 300...control unit, 400...cable, 500...detection unit, 600...control system, 610...servo motor, 620...servo amplifier, 630...command unit, 640...external power supply, C1, C2...capacitor, f1-f3...peak frequency, fa-fd...cutoff frequency, L0-L2...coil, La...primary coil, Lb...secondary coil

Claims

1. A communication system provided between a drive device and a control device that controls operation of the drive device through a cable based on an operating state of the drive device detected by a detection device, a first wiring that connects the control device and the cable, has a first node and a second node, and supplies a first power signal from the control device to the cable; a second wiring that connects the drive device and the cable, has a third node and a fourth node, and supplies the first power signal from the cable to the drive device; a power supply unit connected to the first node of the first wiring and supplying a second power signal; a power receiving unit connected to the third node of the second wiring and configured to provide the second power signal supplied from the power supply unit to the detection device; a first communication unit connected to the fourth node of the second wiring; a second communication unit connected to the second node of the first wiring and configured to transmit or receive a communication signal indicating any information to or from the first communication unit.

2. the first power signal has a first peak frequency; the second power signal has a second peak frequency; the communication signal has a third peak frequency; 2. The communication system of claim 1, wherein the first peak frequency, the second peak frequency, and the third peak frequency are different from each other.

3. 3. The communication system according to claim 2, wherein the second peak frequency is higher than the first peak frequency and lower than the third peak frequency.

4. 4. The communication system according to claim 3, further comprising a composite filter provided in each of said first wiring and said second wiring, said composite filter comprising a band-elimination filter and a low-pass filter.

5. 5. The communication system of claim 4, wherein a first cutoff frequency of said band-stop filter of said composite filter is said second peak frequency.

6. 6. The communication system according to claim 4, wherein the second cutoff frequency of the low-pass filter of the composite filter is between the first peak frequency and the third peak frequency.

7. The communication system according to any one of claims 3 to 5, further comprising a band-pass filter provided between the first node of the first wiring and the power supply unit, and between the third node of the second wiring and the power receiving unit.

8. 8. The communication system according to claim 7, wherein a third cutoff frequency of said band-pass filter is said second peak frequency.

9. The communication system according to any one of claims 3 to 5, further comprising a high-pass filter provided between the fourth node of the second wiring and the first communication unit, and between the second node of the first wiring and the second communication unit.

10. 10. The communication system of claim 9, wherein a fourth cutoff frequency of the high-pass filter is between the second peak frequency and the third peak frequency.

11. the cable is a three-phase cable including three wires; the control device is connected to the three wirings of the three-phase cable by three of the first wirings, respectively; the drive device is connected to the three wirings of the three-phase cable by three of the second wirings, respectively; the first node and the third node are provided on the first wiring and the second wiring, respectively, which are connected to one or more common wirings among the three wirings of the three-phase cable; The second node and the fourth node are respectively provided on the first wiring and the second wiring connected to one or more common wirings among the three wirings of the three-phase cable. A communication system according to any one of claims 1 to 5.

12. the first nodes are provided on the three first wirings, respectively; the third node is provided on each of the three second wirings, 12. The communication system according to claim 11, wherein the power supply unit supplies the second power signals to the three first wirings, the second power signals being out of phase with each other by 120 degrees.

13. the first node is provided on each of two of the first wirings connected to two of the three wirings of the three-phase cable, the third node is provided on each of the two second wirings connected to the two wirings of the three-phase cable, respectively; 12. The communication system according to claim 11, wherein the power supply unit supplies the second power signals to the two first wirings, the second power signals being out of phase with each other by 180 degrees.

14. The power supply unit a signal generating unit that receives a supply of power and generates the second power signal; 13. The communication system according to claim 12, further comprising an internal power supply that is electrically insulated from an external power supply and that supplies power supplied from the external power supply to the signal generating unit.

15. The power receiving unit is a rectification unit that rectifies the second power signal to generate DC power; 6. The communication system according to claim 1, further comprising: a power supply unit that supplies the DC power generated by the rectifier unit to the detection device and the first communication unit.

16. Cable and A drive unit; a detection device for detecting an operating state of the drive device; a control device that controls the operation of the drive device through the cable based on the operating state of the drive device detected by the detection device; A control system comprising: the communication system according to any one of claims 1 to 5, provided between the drive device and the control device.

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