Network device and system with bi-directional energy supply

Abstract

In order to provide an improved, simplified and / or more flexible design of energy supply to bus subscribers and / or energy transfer in a bus system, the invention proposes a network device comprising at least one bus interface (110) for connecting the network device (100) to a bus line (400), in particular a two-wire bus line, wherein the bus interface (110) is designed for data transmission and for energy transmission, and wherein the network device (100) is designed to selectively draw electrical energy from the bus line (400) or to feed electrical energy into the bus line (400) depending on an operating mode of the network device (100). The invention also provides a system having at least two network devices of this type interconnected via a bus line.

Description

Technical Field

[0001] The present invention generally relates to energy and data transmission in a bus system and in particular to a network device for connecting to a bus line and a system having a plurality of such network devices. Background Art

[0002] Different types of bus systems are used in many areas for data transmission between several users. Depending on the intended use, the corresponding bus lines have a different number of wires. Particularly cost-effective and easy-to-operate bus systems barely use 2-wire lines.

[0003] In addition to transmitting data, devices connected to each other via the bus system can also be supplied with electrical energy via the bus system, whereby the bus line can include additional lines for a power supply for this purpose. Supplying power via the bus line offers the advantage that a separate power supply for the devices, for example using separate power cables and network devices or using batteries, can be dispensed with.

[0004] It is also known to use the data lines of a bus system to transmit energy. One such technology is PoDL (power over data line), which is, for example, an improved form of PoE (power over Ethernet), which is used, for example, in the field of industrial automation and IoT (Internet of Things) for simultaneous data and energy transmission via SPE (single pair Ethernet). For example, using PoDL, energy is transmitted from a DC voltage source of a bus user to a receiving device (senke) of another bus user. The separation of additional data transmitted via two lines with relatively high frequencies is achieved by means of frequency crossing (also called duplexing). Inductors and capacitors are usually used because inductors have high impedance for high-frequency data signals, i.e. they act as barriers, while capacitors have low impedance for high-frequency data signals, i.e. they are permeable. For low-frequency DC or AC energy signals of the power supply, the inductor is low impedance, i.e. conductive, while the capacitor has a blocking effect. In this way, data signals and energy signals can be transmitted via the same two lines. Summary of the invention

[0005] The object of the invention is to provide a method which improves, simplifies and / or makes more flexible the energy supply of bus users and / or the transmission of energy in a bus system.

[0006] This object is achieved by the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims, whereby the specified features and advantages may substantially apply to all independent claims.

[0007] Therefore, the above technical problem is solved by a network device, which includes at least one bus interface, which is used to connect the network device to a bus line, in particular to a two-wire bus line, wherein the bus interface is designed for data transmission and energy transmission, and wherein the network device is designed to selectively obtain electrical energy from the bus line or feed electrical energy into the bus line depending on the operating mode of the network device.

[0008] A core aspect of the invention is therefore to provide a network device for connection to a bus line, with which a flexible bidirectional energy transmission can be achieved, for example so that some users can feed energy into the bus while other users can draw energy from the bus. In this way, the network device can also be advantageously supplied with energy during configuration, so that the network device only needs to be connected via the bus interface when operating, for example in order to configure the network device.

[0009] In order to separate the combined data and energy signal present at the bus interface into a data signal and an energy signal, or to combine the data signal and the energy signal into a combined data and energy signal, the network device advantageously comprises a duplex device connected to the bus interface for separating the signals in a frequency-selective manner. In addition, the network device preferably comprises a circuit for energy distribution and a transmission / reception device for transmitting and receiving data, whereby the bus interface is connected to the circuit for energy distribution and to the transmission / reception device via the duplex device. The duplex device is particularly designed to transmit electrical energy between the bus line and the energy distribution circuit, and to transmit data signals between the bus line and the transmission / reception device, in each case bidirectionally.

[0010] The network device can advantageously have an energy supply device, whereby the energy supply device can be designed, for example, as a power supply unit for connection to a mains power supply or as a battery. Preferably, the network device has a normal operating mode and a configuration operating mode, wherein in the normal operating mode, the network device is supplied with electrical energy by the energy supply device, and in the normal operating mode, the network device is designed to feed the electrical energy provided by the energy supply device into a bus line connected to the bus interface, and wherein the network device is designed to obtain electrical energy from the bus line connected to the bus interface in the configuration operating mode in order to supply energy to the network device. The switching between the normal operating mode and the configuration operating mode preferably occurs automatically depending on whether electrical energy is provided by the energy supply device.

[0011] Advantageously, the network device comprises at least one control unit and a storage unit, wherein the network device is designed to supply electrical energy to at least the control unit and the storage unit in a configuration operating mode and to provide access to the storage unit via the control unit for another network device, in particular the configuration device, which can be connected to the network device via the bus interface. The control unit and the storage unit can also be formed by a common unit or arranged in a common unit. For example, an integrated circuit (IC) can be provided, which includes the control unit and the storage unit.

[0012] In this way, at startup, the network device can be configured in a particularly simple manner by simply connecting the network device via a bus interface to a configuration device which supplies the network device with electrical energy via a connecting line, so that the control unit and the storage unit of the network device operate effectively and the configuration parameters can be stored in the storage unit with the help of the configuration device.

[0013] In normal operation, the configuration operating mode is preferably used as an emergency operating mode, whereby the network device is advantageously designed to automatically switch to the configuration operating mode if a power supply device fails. In this way, if the energy supply device of the network device itself fails, the network device can advantageously be supplied with electrical energy via the bus or bus line.

[0014] To avoid interference, it can be advantageously provided that the components of the network device involved in data and / or energy transmission via the bus interface are electrically isolated from other components of the network device. The electrical isolation can be achieved, for example, inductively, capacitively or optoelectronically.

[0015] The energy distribution circuit is preferably designed to receive, smooth, limit, rectify, switch and / or regulate voltage and / or current signals. In particular, the energy distribution circuit can be designed to provide a supply voltage to the control unit and / or the storage unit. By the voltage regulation and smoothing performed by the energy distribution circuit, trouble-free operation of the control unit and / or the storage unit is advantageously ensured.

[0016] Advantageously, the network device comprises a measuring device for measuring the voltage applied to the bus line, whereby the network device is designed to feed electrical energy into the bus line only when the polarity of the voltage applied to the bus line corresponds, or to adjust the polarity of the voltage to be fed into the bus line depending on the voltage measured on the bus line.

[0017] Advantageously, the network device may also have a plurality of bus interfaces, for example at least a first bus interface and a second bus interface. In this embodiment, the network device is advantageously designed to selectively establish or interrupt an electrical connection between the first bus interface and the second bus interface.

[0018] The technical problem is further solved by a system comprising at least two of the above-mentioned network devices and a bus line, in particular a two-wire bus line, via which the network devices are connected to one another.

[0019] It can be particularly advantageous if at least one of the at least two network devices draws electrical energy from the bus line and at least one of the at least two network devices feeds electrical energy into the bus line. In this way, a bus user whose own power supply fails, for example, can be supplied with power by the other bus users. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other advantages, features and possible applications of the present invention will become apparent from the following description of the embodiments and the accompanying drawings. The accompanying drawings show:

[0021] Figure 1 A simplified schematic diagram showing the structure of a preferred embodiment of a network device according to the present invention is shown.

[0022] Figure 2 A schematic diagram showing the principle of how PoDL works,

[0023] Figure 3 A highly simplified schematic diagram showing a first preferred embodiment of the system according to the invention,

[0024] Figure 4 A highly simplified schematic diagram is shown of a second preferred embodiment of the system according to the invention. DETAILED DESCRIPTION

[0025] Figure 1 The basic structure of a network device 100 is shown, which acts as a bus user and therefore has a bus interface 110 for connecting to a bus line. In the example shown, the bus interface is designed for connection to both lines of a two-wire bus line.

[0026] In the exemplary embodiment shown, the network device 100 comprises two areas which are electrically isolated from each other by an isolation barrier, which is indicated by a dashed line 200. In the exemplary embodiment shown, the isolation barrier comprises, for example, a transformer 120 for inductive electrical isolation and a coupler 130, which can be designed for capacitive or optoelectronic electrical isolation and can be designed, for example, as an optocoupler or a digital coupler.

[0027] In this example, the lower region below the isolation barrier comprises the actual device functionality, whereby a power supply 140 is usually arranged therein, as well as a host controller 145 which can be designed, for example, as a microcontroller and is supplied with electrical energy via the power supply 140 .

[0028] The upper area above the isolation barrier mainly includes the components of the network device 100 participating in the bus communication. The electrical isolation of the two areas achieved by the isolation barrier is advantageously used to avoid mutual interference between the corresponding components. It should be noted that electrical isolation is an advantageous design, but is not essential for the operation of the network device.

[0029] In normal operation of the network device 100 , the upper region of the network device 100 is supplied with electrical energy via the transformer 120 , whereby the power supply 140 is connected to the transformer 120 via the drive circuit 141 for this purpose.

[0030] The network device 100 shown also includes an energy distribution circuit 150, which can receive, smooth, limit, switch and regulate voltage and / or current signals, and can also control energy flow. For example, the DC voltage supplied via the transformer 120 and the rectifier schematically shown as a diode 121 can be supplied to the control unit 160 as a power supply voltage in normal operation and optionally to a storage unit 165 connected to the control unit 160 for communication, thereby supplying them with electrical energy accordingly. The control unit 160 can be designed as a microcontroller, for example. The control unit 160 and the storage unit 165 can also be accommodated in a common component. Voltage regulation and smoothing within the energy distribution circuit 150 advantageously ensure trouble-free operation of the control unit 160.

[0031] The control unit 160 can now exchange data with the host controller 145 via the optional isolation barrier, i.e. via the coupler 130, for example using an SPI data interface. The actual data flow via the bus system is ensured by the control unit 160 via a transmission / reception device 170, for example in the form of a transceiver, which is responsible for processing the data, and via a duplex unit 180, which will be explained in more detail below and which transmits and receives data on two bus lines.

[0032] The duplex unit 180 is composed of various hardware components and has various tasks. On the one hand, the duplex unit 180 is designed for frequency separation, whereby the main operating modes of frequency separation performed by the duplex unit 180 are described below in conjunction with Figure 2 Shown.

[0033] Figure 2An example of how to solve the simultaneous transmission of data and energy through SPE (Single Pair Ethernet) using the PoDL (Power over Data Line) method is shown. In the example shown, electrical energy is transmitted to the receiving device 320 of the user 302 via the DC voltage source 310 of the user 301. Since the data is also transmitted at a high frequency via two lines, separation is achieved by means of frequency crossing. The four inductors 331, 332, 333 and 334 shown have high impedance for high-frequency data signals, that is, they act as barriers here, while the four capacitors 341, 342, 343 and 344 have low impedance for high-frequency data signals, that is, they are conductive. For low-frequency DC or AC energy signals, that is, power supply voltage, the inductor is low impedance, that is, conductive, while the capacitor has a blocking effect. This means that data signals and energy signals can be transmitted via the same 2 lines.

[0034] Reference again Figure 1 , the energy supply can therefore be separated from the data signal by means of frequency crossover, ie by means of a duplex unit 180 , for example using inductors and capacitors, as will be explained in more detail below.

[0035] If necessary, a voltage, preferably a regulated voltage, can also be switched from the energy distribution circuit to the bus line via a frequency crossover via the switch 195 and the duplex unit 180. The control unit 160 has control over the switch 195, i.e. the switch 195 is designed as a controllable switch and can be controlled by the control unit 160 via a corresponding control line indicated by a dashed line. The control unit 160 preferably closes the switch 195 only if a measurement performed by the duplex unit 180 shows that no voltage or a correctly polarized voltage is present on the bus line. The result of the measurement is transmitted from the duplex unit 180 to the control unit 160 via a suitable signal or data line. This is done in a controlled manner. Figure 1 195. If the measurement shows that the bus voltage and the bus state (i.e. in particular the polarity of the voltage on the bus line) are suitable for feeding, the voltage can be switched to the bus line by closing the switch 195. It is also advantageously possible to adjust the polarity of the voltage fed into the bus line as a function of the voltage measured on the bus line and in this way achieve reverse polarity protection. For this purpose, a corresponding reverse polarity protection circuit is advantageously provided, which is not Figure 1 Shown in.

[0036] Advantageously, the energy distribution circuit 150 is also designed for current limiting, so that only a current having a predetermined maximum current strength can be provided on the bus line.

[0037] In the following, we consider the actual device functions (e.g. Figure 1The situation that the host controller 145 (represented in FIG. 1 ) fails and / or does not supply power but the network device 100 is connected via the bus line. This can be the case, for example, when the device is put into operation using a special bus configuration adapter not shown. This can also occur if, for example, the network device 100 is defective and therefore cannot provide power via the power supply 140.

[0038] In this case, the duplex unit 180 can forward the voltage present on the bus to the energy distribution circuit 150, for example using a bridge rectifier circuit 190. It should be noted that the voltage present on the bus (i.e. on the bus line) is advantageously provided by at least one other bus user. The advantage of the bridge rectifier circuit 190 is that it enables the current to be drawn independently of the polarity of the voltage applied to the bus line.

[0039] The energy distribution circuit 150 can now advantageously limit, regulate and / or smooth the voltage provided by the duplex unit 180 as required in the manner described and forward the corresponding limited, regulated and / or smoothed voltage as supply voltage to the control unit 160 and / or the storage unit 165, so that the control unit can communicate via the bus as described above despite the lack of device voltage from the power supply 140. For example, even in the event of a fault, configuration data can be read from the storage unit 165 or written to the storage unit 165 during the configuration phase.

[0040] It should be noted that, depending on the intended use, the network device 100 may include Figure 1 Other parts and / or components not shown.

[0041] For example, optional internal termination may be provided.

[0042] In addition to the "duplex" unit, other optional components may be provided, which are not shown in the figure because they are not directly related to the present invention. For example, optional internal terminations may be provided. As mentioned above, a reverse polarity protection circuit may also be provided, which ensures that the communication function is independent of the polarity of the DC voltage applied to the bus.

[0043] Figure 3 An example of a system 10 with three bus users 100-1, 100-2 and 100-3 is shown, whereby each bus user corresponds to a combined Figure 1The network device 100 described above. The bus users are connected to a common two-wire bus line 400 via corresponding bus interfaces 110. It is now assumed that the power supply of bus user 100-3 is defective. As described above, in this case, the present invention advantageously enables bus user 100-3 to be supplied with electrical energy by other bus users 100-1 and 100-2. For this purpose, bus users 100-1 and 100-2 feed electrical energy into bus line 400 as described above, while bus user 100-3 draws electrical energy from bus line 400. This is accomplished by Figure 3 According to the specific configuration of the system, only one of the two bus users 100-1 and 100-2 can still provide energy for the bus user 100-3, or the required energy is provided by the bus users 100-1 and 100-2 in unequal portions.

[0044] This is an advantageous way of ensuring data communication between the three bus devices 100 - 1 , 100 - 2 and 100 - 3 even if the internal power supply of one of the bus devices fails.

[0045] To keep it simple, Figure 1 The network device 100 is shown to comprise only one bus interface 110. However, depending on the type and topology of the bus used, the network device according to the invention may also have a plurality of bus interfaces or ports.

[0046] Figure 4 An exemplary embodiment of a system 20 according to the present invention is schematically shown in FIG. 2 , wherein the network device has a plurality of ports. Figure 4 A highly simplified sketch showing the connections of three network devices 510, 520, and 530 within a network topology. Figure 4 As can be seen in FIG. 1 , the network 20 shown includes, for example, first, second and third network devices 510, 520 and 530, each of which is electrically connected to the bus 600. The bus 600 shown can be advantageously designed as a two-wire bus, and Figure 4 In the exemplary embodiment, a daisy chain topology is constructed so that a point-to-point connection is established between each network device 510, 520 and 530 of the system 20, and the network devices 510, 520, 530 are arranged in a row or chain. To this end, Figure 4 Each individual network device 510, 520, 530 in the example of the embodiment includes two connection ports 511, 512, 521, 522, 531, 532, also referred to as ports or physical connection points, wherein the first connection port 512 of the first network device 510 is connected to the first connection port 521 of the second network device 520, and the second connection port 522 of the second network device 520 is connected to the first connection port 531 of the third network device 530. Even if Figure 4Not shown, other network devices on the left side of the first network device 510 and / or on the right side of the third network device 530 may still be connected to the network 20 or may be connected to the bus system 600 according to the network topology used.

[0047] exist Figure 4 In the illustrated network 20 , the network devices may advantageously include circuit components designed to selectively establish or interrupt an electrical connection between a first bus interface and a second bus interface of a corresponding network device. Figure 4 The network device shown advantageously has an analog structure for bidirectional energy transmission, that is, it can selectively provide power to the bus or obtain power from the bus, as described above in conjunction with Figure 1 The network device 100 is shown.

[0048] As described above, the present invention advantageously enables a bus device to be used both as a power source and as a power receiving device, i.e. as an energy transmitter or receiver depending on the operating mode. In this way, a flexible bidirectional energy transmission can be achieved, whereby, for example, some bus users can feed power to the bus and other bus users can draw power from it. In addition, for ease of use, it can be advantageous to provide reverse polarity protection, in particular for bus devices acting as power sources, so that a rectifier can be provided, in particular for bus devices acting as power receiving devices, in order to provide a voltage of a predetermined polarity, regardless of the polarity of the voltage applied to the connected bus line. Another advantage of the present invention is that if the bus users are connected and configured when, for example, they are put into operation only via the bus line, power can also be provided in the case of configuration.

[0049] Reference numerals list

[0050] 10, 20 system

[0051] 100 Network devices

[0052] 100-1, 100-2, 100-3 Network device with one bus interface

[0053] 110 bus interface

[0054] 120 Transformer

[0055] 121 Rectifier

[0056] 130 Coupler

[0057] 140 Power Supply

[0058] 141 Driving Circuit

[0059] 145 Host Controller

[0060] 150 Energy Distribution Circuit

[0061] 160 Control Unit

[0062] 165 Storage Units

[0063] 170 Transceiver

[0064] 180 duplex units

[0065] 190 Bridge Rectifier

[0066] 195 Controllable switch

[0067] 301, 302 users

[0068] 310 DC voltage source

[0069] 320 Receiving device

[0070] 331 to 334 Inductor

[0071] 341 to 344 Capacitor

[0072] 400 bus lines

[0073] 510, 520, 530 Network devices with two bus interfaces

[0074] 511, 512 bus interface

[0075] 521, 522 bus interface

[0076] 531, 532 bus interface

[0077] 600 bus.

Claims

1. A network device (100), comprising: - at least one bus interface (110) for connecting the network device (100) to a bus line (400), in particular a two-wire bus line, the bus interface (110) being designed for data transmission and for energy transmission, and the network device (100) being designed to draw electrical energy from the bus line (400) or to feed electrical energy into the bus line (400) depending on the operating mode of the network device (100).

2. The network device according to claim 1, comprising: - a duplexing device (180) for separating the signals in a frequency-selective manner, - an energy distribution circuit (150), and - a transmission / reception device (170) for transmitting and receiving data, wherein The bus interface (110) is connected to the energy distribution circuit (150) and to the transmission / reception device (170) via the duplex device (180).

3. The network device according to any of the preceding claims, comprising an energy supply device (140), The network device (100) is supplied with electric energy by the energy supply device (140) in a normal operation mode, and is designed to feed the electric energy provided by the energy supply device (140) into a bus line (400) connected to the bus interface (110) in the normal operation mode, and The network device (100) is designed to obtain electrical energy from a bus line (400) connected to the bus interface (110) in a configuration operation mode, so as to supply energy to the network device (100).

4. The network device according to claim 3, comprising: - at least one control unit (160), and - a storage unit (165), The network device is designed to supply electrical energy to at least the control unit (165) and the memory unit (165) in the configuration operating mode and to provide access to the memory unit (165) to another network device, in particular a configuration device, via the control unit (160), which can be connected to the network device (100) via the bus interface (110).

5. The network device according to claim 4, which is adapted to automatically switch to the configuration operating mode in the event of a failure of the energy supply device (140).

6. A network device according to claim 4 or 5, wherein the components of the network device (100) involved in the data transmission and / or energy transmission via the bus interface (110) are electrically isolated from other components of the network device (100).

7. The network device according to any of the preceding claims, wherein the energy distribution circuit (150) is configured to receive, smooth, limit, rectify, switch and / or regulate voltage and current signals.

8. A network device according to any of the preceding claims, wherein the network device (100) comprises a measuring device for measuring the voltage applied to the bus line (400), and wherein the network device (100) is designed to adjust the polarity of the voltage to be fed into the bus line (400) according to the voltage measured on the bus line (400).

9. A network device (510, 520, 530) according to any one of the preceding claims, wherein the network device comprises at least a first bus interface (511, 521, 531) and a second bus interface (512, 522, 532), and wherein the network device (510, 520, 530) is designed to selectively establish or interrupt an electrical connection between the first bus interface and the second bus interface.

10. A system (10, 20), comprising: - at least two network devices (100-1, 100-2, 100-3, 510, 520, 530) according to any one of claims 1 to 9, and - a bus line (400, 600), in particular a two-wire bus line, The network devices are connected to each other via the bus line.

11. A system according to claim 10, wherein at least one network device (100-3) of the at least two network devices (100-1, 100-2, 100-3) obtains electrical energy from the bus line (400), and at least one other network device (100-1, 100-2) of the at least two network devices (100-1, 100-2, 100-3) feeds electrical energy into the bus line.

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