BUS-CAPABLE LIGHTING SYSTEM PARTICIPANT WITH DECENTRALIZED BUS POWER SUPPLY

Description

[0001] The present invention relates to bus-capable lighting system participants, such as actuators and sensors in a lighting system with bus connection, as well as to methods for operating such a bus-capable lighting system participant.

[0002] The lighting system preferably has a bus designed to carry voltage in the idle state and thus serve as a power supply for actuators and sensors in the lighting system. An example of such a bus is the Digital Addressable Lighting Interface, or DALI for short, which is standardized in IEC 62386.

[0003] In building automation, DALI is a protocol for controlling lighting control devices, such as switching power supplies, electronic ballasts or electrical power dimmers, in order to control lamps, monitor their operating status and / or supply them with power.

[0004] Each control gear with a DALI interface can be individually controlled via corresponding DALI addresses and can change the intensity of a lamp or a sensor in the lighting system. Actuators are also provided. Bidirectional data exchange between a DALI control gear and a DALI device determines, for example, the status of an individual lamp or a group of lamps, or the control gear itself, and can also control it. DALI uses a serial asynchronous data protocol with a transmission rate of 1200 bps at a voltage level of 16 V using two-wire communication.

[0005] The lighting system's power supply is provided via a separate bus. Two communication lines, DA+ and DA-, are preferably galvanically isolated from the mains supply and polarity-free. These two communication lines, DA+ and DA-, also serve as power supply lines. These lines can be laid in any topology, i.e., star, line, or tree structure. Terminating resistors at the end of the power supply lines are not necessary. The two communication lines, which also serve as power supply lines, are referred to below as the power bus.

[0006] The DALI standard IEC 62386 stipulates that a maximum of 64 actuators can be controlled per bus. The maximum current consumption of the bus is limited to a specified value and is preferably 250 milliamperes, which is referred to below as the maximum current consumption.

[0007] To ensure that the maximum current draw of 250 milliamperes from the bus is not exceeded, a dedicated DALI power supply unit is provided. This DALI power supply unit generates a constant output current of nominally 200 milliamperes to 250 milliamperes at a supply voltage of 16 volts in the lighting system's standby mode.

[0008] The bus devices connected to the bus are not designed for a current draw above the specified maximum current draw, so the bus devices must be protected from current draw exceeding the maximum current draw. In particular, parallel connection of several DALI supply units is therefore not possible, as parallel connection would generate an output current on the bus that exceeds the maximum current draw.

[0009] Furthermore, according to the DALI standard IEC 62389, communication between individual elements of the lighting system, hereinafter also referred to as bus devices, is impossible until a start-up procedure wait time has elapsed. Only after this start-up procedure wait time has elapsed is the DALI bus considered stable and allows communication between the bus devices. The start-up procedure wait time is preferably 600 milliseconds.

[0010] If several DALI supply units were operated in parallel, a current flowing through the bus could exceed the maximum current draw within this start procedure waiting time, which could overload the bus devices and thus damage or destroy them.

[0011] WO 2017 / 046248 A1 discloses a supply unit for a bus. The bus device has a supply unit that outputs a measuring current to a building services bus. A control unit of the bus device detects and evaluates a bus current on the building services bus. DE102011080500A1 discloses another bus power supply for detecting short circuits.

[0012] Based on this prior art DE102011080500A1, the object of the present invention is to improve the connection of a decentralized power supply in a bus-capable lighting system participant to a bus that is live in the idle state.

[0013] This problem is solved by the features of the independent claims.

[0014] The dependent claims develop the central idea of ​​the invention in a particularly advantageous manner.

[0015] The invention therefore proposes a bus-capable lighting system device that has a power supply and connections for supplying a bus. Since the device can supply the bus that is not the central unit, a decentralized bus supply is present, which requires special measures and designs.

[0016] The bus is designed to carry voltage, specifically a non-zero DC voltage, in the idle state (no transmission on the bus). Furthermore, the device has a control circuit designed to detect a change in the voltage on the bus as a result of each of the following two events: a) Change in the voltage on the bus after the power supply of the participant is switched on, and b) Change in the voltage on the bus after the participant short-circuits the bus.

[0017] The control circuit is designed to detect, when the voltage supply is switched on to the bus, whether the polarity of the voltage on the bus changes during the switching on.

[0018] The control circuit is designed to detect how quickly the bus voltage recovers after a short circuit, i.e. how quickly it rises from the short-circuit level (0 V) back to the DC voltage level before the short circuit.

[0019] Typically, such a lighting system participant is an actuator such as a control device for light sources (LEDs, OLEDs, gas discharge lamps, etc.) or a sensor (motion sensor, presence sensor, light sensor such as daylight sensor, smoke detector, etc.).

[0020] The invention also relates to a method for operating a bus-capable lighting system device. The device has a power supply that can be selectively connected to supply a bus that is live in the idle state. For this purpose, the device preferably has two connections for supplying a pair of lines of the bus. According to the method according to the invention, the change in the bus voltage, i.e., the change in the DC level, is detected as a result of each of the following two events by the device: a) Switching on the power supply (of the participant), and b) Short-circuiting the bus by the participant.

[0021] Further features, advantages and properties of the invention will now be explained with reference to the figures of the accompanying drawings: The figure shows an embodiment of a decentralized bus participant according to the invention with a supply unit.

[0022] In Fig. 1 A supply unit 1 is shown, which according to the invention is part of a (decentralized) bus device, particularly in the field of building technology. The device with a bus supply unit can, for example, be an actuator (operating device for light sources) or a sensor in the field of lighting technology.

[0023] The supply unit 1 comprises input connections 2, represented as the mains line L and the neutral line N. The invention does not preclude the use of a supply unit 1 that additionally has a protective conductor PE. The supply unit 1 also has a DALI interface, represented here as a bus 3 with the lines DA+ and DA-. Such DALI supply units serve to supply a bus 3 with a DC voltage, to which additional DALI operating devices, electronic ballasts or power dimmers, actuators, or sensors are connected as bus devices. Preferably, however, no central bus supply is provided. Additional devices can also have bus supplies.

[0024] The supply unit according to Fig. 1For example, it is configured to supply bus 3 with a current of 240 milliamperes. A mains supply voltage of 220 volts to 240 volts is applied to input terminals 2. The mains supply voltage typically has a frequency of 50 or 60 hertz. The supply unit is therefore designed to deliver 5 watts of power. The output voltage is 16 volts with a tolerance of + / - 5%. The DALI signal is not SELV.

[0025] A control unit 4 is provided in the supply unit 1. The control unit 4 is designed, for example, as a microcontroller, as an ASIC, as an FPGA or CPLD. The control unit 4 is connected to the bus 3. A short-circuit switch 5 is also provided in the supply unit 1. The short-circuit switch 5 is provided to short-circuit the bus 3. For this purpose, the short-circuit switch 5 has a first switching state I in order to connect the lines DA+ and DA- to one another. In a second switching state II, the short-circuit switch 5 removes a connection between the power supply lines DA+ and DA-. The change in the switching state of the short-circuit switch 5 is initiated by the control unit 4. For this purpose, a switching signal is generated by the control unit 4. By means of the short-circuit switch 5, a current draw from the bus 3, which flows through the supply lines DA+, DA-, can now be detected.For this purpose, a measuring element 6 is provided in the connection between the supply lines DA+, DA-. The control unit 4 is designed to detect a voltage drop across, for example, a measuring element 6 designed as a current measuring resistor when the short-circuit switch 5 is short-circuited. Alternatively, a galvanic coupling is achieved via the measuring element 6, for example, using coupled coils, or alternatively using an optocoupler. The detected current draw from the bus 3 is evaluated in the control unit 4. Depending on the current value and in comparison to a predetermined value lx for a maximum current draw, for example, 240 mA according to the DALI standard IEC 62389, the supply unit 3 then provides a power supply to the bus 3 and opens the switch 5, or it does not provide the power supply and opens the switch 5.

[0026] Optionally, a memory element 7 is provided in the supply unit 1. This memory element 7 stores, for example, DALI addresses, DALI lighting groups, DALI lighting scenarios, and / or dimming values ​​intended for a specific setting of the lighting system A. When an operating device 8 in the lighting system A is replaced, the settings of the lighting system A can now be saved using the memory 7. All relevant data of the elements 8 connected to the lighting systems A can thus be stored in the memory 7. This data in the memory 7 thus serves as backup data in the event that an operating device in the lighting system A needs to be replaced. Inventive procedure for connecting the decentralized bus supply of a subscriber:

[0027] The inventive design of a participant or a method according to the invention is now as follows: Step 1:

[0028] In a first step, the device with the supply unit measures whether a power supply is already connected to the DALI bus. This power supply can be a centralized or decentralized power supply. However, it is preferable not to use a centralized power supply. This allows the device to determine, for example, whether current is flowing at the two DALI bus connections. If the result of this check is no, the power supply of the corresponding device is connected. No further testing steps are performed. Step 2:

[0029] However, if the result of step 1 is yes, meaning a measurable current can already flow between the terminals of the subscriber's DALI bus, the subscriber's own decentralized bus power supply is switched on. The subscriber's control unit checks whether a polarity reversal of the DC voltage on the DALI bus occurs when its own power supply is switched on, for example by the subscriber detecting whether the voltage on the bus crosses zero. If the result of this check is yes, meaning a polarity reversal occurs, it is concluded that the polarity of the subscriber's own power supply is reversed to the prevailing polarity on the DALI bus, and the subscriber switches its own DALI power supply off again. Preferably, no further steps are required. Alternatively, the polarity of the decentralized bus power supply is inverted and the process continues with step 3.

[0030] If the result of the check is "no," meaning no polarity reversal occurs, it is concluded that the polarity of the prevailing DALI polarity is identical to the polarity of the DALI supply of the device itself. The system then proceeds to step 3. Step 3:

[0031] The device sends test signals on the DALI bus, which means that the DALI bus, which carries the DC level in the idle state, is selectively short-circuited. The bus is then released again. The device records how long it takes for the DALI idle bus voltage to build up again after the DALI bus is short-circuited.

[0032] This duration measurement, or measurement of the steepness of the rising edge of the DALI DC bus voltage, is performed by the device once without the connected DALI power supply and once with its own DALI power supply connected. The device thus determines in which of the two scenarios the edge recovers more quickly, which means determining in which scenario (with or without its own connected DALI power supply) the power supply for the bus is stronger.

[0033] The test will then continue with the constellation in which the edge of the DALI bus recovered more quickly after short-circuiting. Step 4:

[0034] In the event that the scenario with a faster recovering rising edge of the DALI bus is the one in which the participant's own DALI supply is connected, the participant performs the following check: According to the DALI standard, as already explained above, there is a maximum limit of 250 milliamperes that can be supplied and consumed via the bus.

[0035] In this test step, a function or a table is used to check whether the resulting edge steepness when the bus is released (resolving the short circuit) is so large that a power supply of more than 250 milliamperes is detected.

[0036] If this happens, i.e., if the bus state "Logic high" recovers too quickly, the separate DALI supply is switched off again. This is a safety check to ensure that the maximum permissible current for the DALI bus is not exceeded.

[0037] If the bus idle state does not recover too quickly, the decentralized supply remains connected to the bus.

[0038] According to the invention, if it is determined that the polarity of the internal DALI supply is opposite to the prevailing polarity on the DALI bus, the polarity of the internal DALI supply is inverted.

Claims

1. Bus-capable lighting system user, comprising a voltage supply which can be selectively connected to supply a bus (3) which carries a voltage in the idle state, and a control circuit (4) which is designed to detect a change in the bus voltage as a result of each of the following two events: a.) the connection of the power supply of the user, and b.) a short-circuiting of the bus (3) by the user; characterized in that the control circuit (4) is further designed to detect, when the voltage supply is connected to the bus (3), whether the polarity of the voltage on the bus (3) changes in the course of the connection, and in that the control circuit (4) is designed to invert a polarity of the power supply of the user if the polarity of the voltage on the bus (3) changes during the aforementioned connection, and, if the polarity of the voltage on the bus (3) does not change, to short-circuit the bus, and after subsequent release: to detect how quickly the voltage on the bus rises after the short-circuit from the short-circuit level to the DC voltage level before the short-circuit, this being carried out once with and once without the power supply of the user being connected, or to detect the steepness of the rising bus voltage edge, this being carried out once with and once without the power supply of the user being connected.

2. Lighting system user according to the preceding claim, which is an operating device for lamps or a sensor.

3. Bus-based lighting system comprising one or more users according to either of the preceding claims.

4. Method for operating a bus-capable lighting system user, comprising a voltage supply which can be selectively connected to supply a bus (3) which carries a voltage in the idle state, a change in the bus voltage as a result of each of the following two events being detected in the method: a.) the connection of the power supply, and b.) a short-circuiting of the bus (3); characterized in that, when the voltage supply is connected to the bus (3), it is detected whether the polarity of the voltage on the bus (3) changes in the course of the connection, and in that during the aforementioned connection, if the polarity of the voltage on the bus (3) changes, the polarity of the power supply of the user is inverted, and if the polarity of the voltage on the bus (3) does not change, the bus is short-circuited, and after subsequent release: it is detected how quickly the voltage on the bus rises after the short-circuit from a short-circuit level to the DC voltage level before the short-circuit, this being carried out once with and once without the power supply of the user being connected, or the steepness of the rising bus voltage edge is detected, this being carried out once with and once without the power supply of the user being connected.