DE102007044816B3 - Method for operating a bus system - Google Patents

Abstract

A bus system comprises a control unit 1 and a bus 5 originating from the control unit 1 with a signal transmission device. The bus 5 comprises at least two bus nodes 3, 4 connected via bus coupling points 6, 7 to the signal transmission device 2 of the bus 5. The bus system further comprises a second bus 12, designed as a structure bus, starting from the control unit and connected to the bus users 3, 4 is that these are addressable based on their arrangement in the second bus 12. In a method for operating a bus system comprising a bus 5, the bus subscribers 3, 4 are assigned individual addresses for initializing the bus 5 by means of a second bus 12 in accordance with their physical arrangement in this bus 12. In a method for operating a bus system comprising a bus 5, a second bus 12 for reactivating sleeping bus users 3, 4 and / or the control device 1 is used to implement a power-saving mode for the bus system.

Description

The The invention relates to a method of operating a first one Bus and several bus participants comprehensive bus system, in which the Bus participants over a separate from the first bus unidirectional second bus are connected in series in a row, wherein during the Initialization of the bus system of each bus participant in the direction of Operating the second bus, a message to the in-line arrangement downstream bus participant sends.

bus systems for communication spatially distributed System components, such as actuators, sensors and control units are known. Bus systems are used, for example, in vehicles, in systems for the office communication and in the field of automation technology. To automate the building technology Installation busses are used, wherein by means of a bus system Domestic appliances, Components of an alarm system and the devices for heating or air conditioning centrally controlled and remotely operated.

The Control of lighting equipment enabled by means of a bus system a user, for example, a plurality of bulbs simultaneously to control and by means of a single switch operation, for example select a programmed lighting scene for a variety of lamps a predetermined brightness is set, which is a typical Usage situation corresponds. Such a lighting control can also be made automated by using brightness sensors stocked Bus subscriber sensor data to the control unit return, then the corresponding its programming the building lighting automatically adjusts.

Examples for bus systems for control of lighting equipment are the control protocol DALI (Digital Addressable Lighting Interface), preferably for stage lighting used control protocol DMX (Digital Multiplex) and the on the European Installation bus (EIB) based KNX standard. Each one on such Bus system connected lighting device includes in addition to the actual Bulb or the photometric sensor a resource with a bus coupler, through which the respective lighting technology Device the Data exchange with the signal transmission device realized the bus system and executes the associated digital protocol.

following is for the different devices connected to the bus use the term "bus subscribers", preferably are this busable lighting equipment. For one such bus participants is a separation of the power supply and the device control so that the operating state, such as the on / off state or a Dimmer position, for each bus participant can be set individually.

To the It is necessary to address this to a single bus user to assign a unique address during initialization. In the simplest In case this is done by the setting of coding switches at the respective Attendees. This process may be for reasons of accessibility the coding switch or their small size be expensive. Furthermore the setting of coding switches is a possible source of error in the System initialization.

Alternatively, it is possible to work with predetermined serial numbers or random addresses which, in the case of a bidirectional bus system, the bus subscriber can report to the control unit during initialization. If this option is not given, then an address input must be made directly on the control unit, which in turn creates the risk of incorrect input. As an alternative to initialization is in DE 199 09 646 A1 discloses an individual address assignment for a lighting control installation bus. In this case, each bus subscriber connected to the installation bus comprises a resource and a light source. After connecting to the installation bus, the contact between the lamp and the equipment is briefly disconnected. As a result of this measure, the bus subscriber for the control unit is recognizably selected, since with a light source that is not connected, the operating medium transmits a message via the bus to the control unit. During the initialization phase, the controller responds with an address assignment. The method described above is particularly complicated when starting up larger, locally distributed lighting installations.

Another initialization procedure is through the DE 44 22 215 A1 disclosed. At the beginning of initialization, all bus subscribers have originating addresses that do not include information regarding their arrangement or grouping. These source addresses are first transmitted to the control unit in the bus system. The controller then activates each of the bus users individually with its source address. In the case of a light source provided in the bus subscriber, this activation may be a change in the illuminance, for example. At a selected bus subscriber, a monitoring device is installed which, in the event of activation, provides feedback to the control unit. In this case, the source address is replaced by an operating address from which the spatial arrangement or the classification of the bus user can be read. The The procedure is then repeated for each of the other bus subscribers, ie the supervisor is then re-placed each time. Accordingly, this initialization process, in particular for spatially extended installation bus systems in the implementation consuming.

An alternative to the assignment of individual addresses during initialization is when a bus station can only be addressed by its physical positioning in the bus system. This is given for the special case of a bus system in daisy-chain arrangement, in which the signal transmission device is designed so that the bus users are connected in a series arrangement. This is understood to mean a special bus topology for which each bus subscriber comprises a receiver and a transmitter. The receiver receives the data stream of the signal transmission device, processes it, possibly the data packets are modified or regrouped before they are in turn forwarded via the transmitter to the subsequent bus subscriber. Accordingly, the data stream passes through each bus subscriber in the series arrangement successively. Therefore, it is possible to uniquely identify and select each individual bus subscriber based on its position within the series arrangement. A bus system with the above-described series arrangement is, for example, in EP 1 530 108 B1 disclosed. A disadvantage of a bus system with daisy-chain arrangement is that in the event of failure of a single bus subscriber, the bus subscribers following in the series arrangement fail due to the separation in the bus for lack of controllability.

Further is the basic requirement for installation bus systems, to minimize their energy consumption. Especially complex Bus systems and the sum of the connected bus subscribers have a noticeable power consumption. Accordingly many times a power saving mode is provided in which the bus system or parts the bus system or the connected bus participants in one Go to sleep mode. To ensure that operation by a user too a control reaction leads, it is necessary, at least the query function of the controls regularly out to reactivate the sleep mode. However, there are longer periods of sleep the problem that a user has a significant delay in the execution of an actuating request perceives, which is disadvantageous is.

Out DE 44 28 502 A1 a bus system is known, comprising a control unit and an outgoing from the control unit bus with a signal transmission device and at least two connected via bus coupling points with the signal transmission means of the bus bus subscribers. The bus system is further associated with a second bus line, which is connected to the bus participants such that they are addressable according to their physical arrangement in this further bus line. As a result, an automatic address assignment to the bus participants is made in accordance with the respective activation of the inputs and outputs of the individual bus subscribers.

Basically identically constructed bus systems, as in DE 44 28 502 A1 are described, too DE 197 56 564 A1 such as EP 1 284 556 A1 known. The latter document also discloses the provision of a feedback of an individual address assignment of a newly addressed bus subscriber on the first bus to the control unit.

An automatic addressing of individual bus participants during the initialization of a bus system is in DE 10 2004 052 075 A1 described. Furthermore, it is off DE 199 47 407 C2 It is known to wake dormant bus subscribers by a signal sent over the second bus so that it receives a communication link with the controller via the first bus.

DE 197 15 880 C1 and FR 2 844 085 B1 each disclose a method of operating a bus system with a power saving mode in which the bus users are put into a sleep mode and reactivated as needed.

outgoing From this prior art, the invention is based on the object to develop a method of the type mentioned above in such a way that this optimized in terms of lower power consumption can be operated.

Is solved this object by a method having the features of the claim 1.

This Bus system is characterized by the use of two from each other independent and preferably different buses. A first bus is for normal operation provided and may depend on be selected adapted to the present control task. In particular it for the first bus not necessary to train this as a structure bus, because the physical position of a single bus device is itself not directly from the bus topology. For normal operation This means that a single bus participant due to a fault can be omitted without the first bus associated with the signal transmission device to interrupt. Typically, the first bus is designed to handle this also larger data volumes transferred quickly can be.

Further, as a first bus, a serial or a parallel bus can be used. For both off It is preferred to configure the first bus bidirectionally, so that feedback from the individual bus users to the control unit is possible.

Of the used according to the invention for the bus system second bus is as a structure bus, in particular in the form of a daisy-chain arrangement created. This results from the specially selected bus topology auto matically the physical arrangement of the connected bus devices. Prefers this is achieved in that the structure bus is a signal transmission device each having over the bus devices leads. Accordingly, each bus device has one receiver and a transmitter, wherein a communication link between the transmitter of a bus device and the receiver a physically subsequent further bus device. This results a defined series arrangement, resulting in a simplified installation the entire bus system can be used. This second, as Structured bus designed bus needs in a very simple configuration only a very small amount of data and ultimately only one signal transmitted to can. For this reason, this is much simpler and can be operated with a significantly lower energy consumption.

To initialize the bus system with its bus participants, the following steps are performed:
The starting point is initially a bidirectionally operated first bus. This is used to uniformly transmit a first address to the connected bus subscribers. This first address may comprise, for example, a structure counter with its start value, for example the value 1, or in the simplest case, the address of the structure counter itself.

In In a second method step, the second bus - the structure bus - is run through by the control unit, wherein along the series arrangement, the bus subscribers received Message from each bus participant is processed so that for the subsequent Bus subscriber an individual address arises. In the simplest Case this is realized by means of the structure counter, as above shown at the beginning of the run to a defined initial value, for example, set to 1. Is in every bus participant the structure counter increased by the value 1, so receives Each bus participant has a unique structure meter assignment, which is the simplest Case of the individual address corresponds. Due to the different Bus speeds, where the speed of the first bus a multiple of the speed of the second, as a structure bus trained bus, the two methods can in principle also be started at the same time.

is the first bus is bidirectional, it is possible to that each bus participant after the allocation of an individual Address a feedback on the first bus to the controller conducts, receives accordingly the control unit as information the total number of connected to the bus system Bus subscriber and can therefore derive the individual addresses. Accordingly, then in the sequence an addressing of individual bus participants possible, which reflects their physical arrangement. In addition, can the control unit the Accuracy of the procedure by a successive addressing query the individual bus participant.

alternative for feedback can at the control unit immediately the number of bus subscribers are entered, so it also possible is a simplified, only unidirectionally operable first Bus to use. Alternatively, the structure bus can be designed in such a way that he has an annular Topology, d. H. the transmitter of the in-line arrangement last bus subscriber is in communication with the Controller, so that when passing through the series arrangement of the state of the structure counter on last bus subscriber reported back by means of the second bus to the control unit then, in turn, becomes aware of the set individual Receives addresses and thus over the first bus can address the individual bus participants.

According to one Another exemplary embodiment, the passage through the series arrangement of Bus participants in the second bus not from the control unit, but from the end of Row arrangement of, d. H. starting with the bus subscriber who is in relation to the row shaped Topology of the second bus farthest from the controller is arranged. Will this be the starting value of the structure counter, typically 1, and correspondingly in the backward passage of the series arrangement the bus participant of the structure counter in every single bus device increased by the value 1, This again creates an individual addressing. In addition will the last structure counter value from the transmitter of the controller closest Bus participant transmitted to the control unit, so the controller receives the necessary information regarding the address assignment. In the simplest Case, this in turn is the knowledge of the number of connected Bus devices.

The second bus, which is designed as a structure bus, serves for addressing which reflects the physical arrangement of the bus users and is therefore used predominantly during the installation phase of the bus system. Accordingly, according to a preferred embodiment during normal operation, in which the bus users in terms their function is not needed, the second bus to be switched off.

Of the second bus will be executed a power saving operation of the bus system used by the simple created and thus little energy consuming second bus to transfer the Bus system or the first, the data transmission bus from sleep mode to normal operation mode. there may be the second bus to fulfillment This task can be used differently, depending on whether in sleep mode only the bus participants or a part of this or also in addition the control unit is set to a standby mode.

Becomes for example the first variant is a bus-capable one Switching element operated by a user, so in the case of a bidirectional first bus of these bus participants a message to the control unit deliver. All other bus subscribers are at this time to Saving energy in a sleep mode, d. H. their coupling devices to the first bus are disabled, so that one output via the first bus Message from a sleeping bus subscriber, for example one Luminaire, not processed. Therefore, first by means of the second bus, while of the energy-saving mode is active, the switching of the bus participants in the normal operating state causes. For this purpose are preferred at least the recipients the bus participant for the second bus constantly active, so starting from the control unit, the entire row arrangement starting with the control unit closest bus device can be activated. This is when activating a bus station this will resume its connection to the first bus and in addition Signal via its transmitter on the second bus to activate the following bus device send. Successively, all bus subscribers are reactivated in this way and are over the first bus accessible and thus controllable.

As set forth above, there is another variant in the embodiment of the energy saving operation therein, in addition to the control unit itself in to bring a standby mode. Will be for this case a single Bus participants about by an intervention by a user from the outside activated, so will first one from the respective bus subscriber on the bidirectional first Bus delivered message not perceived by the sleeping control unit. To activate it, the second bus is used again. in this connection it is necessary that along the row arrangement on the second bus of Bus subscribers to bus subscribers passed a message to the control unit can be. This assumes that the sequence consists of recipients and Transmitters to the control unit takes you. According to one embodiment this is achieved by means of a ring-shaped Topology for the second bus.

alternative is for every bus user the sender and receiver pairing with respect to the sender side to the control unit to align, d. H. the closest to the controller bus participants is connected by means of its transmitter with the control unit. In the foregoing, was a corresponding design variant in connection with an inverse, starting from the bus termination point initialization shown. If there is a connection to the control unit, then the Reactivation of the individual bus participants to the control unit itself be made. If this is activated, then the actual Message on the first bus to be processed and to a corresponding one Lead tax result.

following the invention with reference to an embodiment with reference on the attached Figures described. Show it:

1 FIG. 1: A schematically illustrated bus system with a first bus for the control of bus users during normal operation and an additional second bus in the form of a structure bus, optionally designed as a ring structure, FIG.

2 a further embodiment of a bus system with a second bus, whose unidirectional communication takes place towards the control unit and

3 : A diagram illustrating the initialization procedure for initializing the in 1 shown bus system.

An in 1 shown bus system B includes a control unit 1 from which two buses 5 . 12 out. The control unit 1 serves to control the two buses 5 . 12 , A first bus 5 comprises a signal transmission device 2 and reaches to a termination point 15 , With this first bus 5 is a first bus participant 3 over the first bus connection point 6 and a second bus participant 4 via the second bus connection point 7 in connection. In this figure, only two bus subscribers, namely the bus subscribers 3 . 4 for the sake of simplicity. At the first bus 5 a large number of other bus subscribers can be connected.

Every bus participant 3 . 4 typically includes a separate item of equipment not shown in detail, which includes the means for bus connection and the means for operating the device component of the subscriber. For a lighting device, this is, for example, a light source, such as an LED, a lamp or the like, or a light source group or a sensory device, about a brightness sensor. In the schematically simplified representation of 1 the voltage supply for the bus participants or the control unit is not shown in detail.

The example of a 2-wire arrangement sketched first bus 5 can for normal operation of the bus system, ie the control of the bus participants 3 . 4 , suitably chosen. In this case, the bus may be serially applied, in which case the 2-wire arrangement may be used to carry out a non-inverted and an inverted serial transmission channel. Furthermore, the use of a parallel bus as the first bus 5 conceivable. In this case, the signal transmission device 2 to design accordingly. In addition, the first bus 5 be created with any topology - to simplify the presentation is in 1 the first bus 5 presented stranded.

The bus system B, as already noted, a second bus 12 assigned, which also from the control unit 1 goes out and is designed as a structure bus. This is by a simple, unidirectional second bus 12 went out. Shown is a daisy-chain arrangement in which the bus subscribers 3 . 4 in a series arrangement in the structure bus 12 are involved. Each participant receives a bus 3 . 4 in the series arrangement over the second bus 12 transmitted signals from the preceding with respect to the arrangement bus subscriber. Accordingly, the transfer of the data flow to the subsequent bus subscriber takes place, wherein the data stream can be modified or regrouped within a bus subscriber. To carry out such a daisy-chain arrangement, the first bus subscriber comprises 3 a first receiver 8th and a first transmitter 9 and the second bus participant 4 a second receiver 10 and a second transmitter 11 , According to the sketch 1 there is a communication connection 13 in each case between the transmitter of the preceding bus subscriber to the receiver of a subsequent bus subscriber. Sketched in 1 is a communication connection 13 between the first transmitter 9 and the second receiver 10 , Furthermore, the first recipient stands 8th with the control unit 1 and the second transmitter 11 over a connecting line 14 with the Steuerge advises 1 in communication connection, so according to this embodiment, the second bus 12 is annular and one from the control unit 1 outgoing going back to the controller 1 returns. It should be noted that the connecting line 14 is optional and in principle only required if of the last in the series arrangement bus subscriber, here the bus subscriber 4 over the structure bus 12 a feedback to the controller 1 should be done. Basically, the connection is 14 not required.

2 shows an embodiment variant that no connection line 14 having. The denote with 1 matching reference numerals of the illustrated bus system B 'maintained for this embodiment components. Notwithstanding 1 For the illustrated embodiment, a line-shaped topology for the second bus 12 ' used. In the illustrated embodiment, the receiver / transmitter pairs are for each bus subscriber 3 . 4 each arranged so that the unidirectionally applied second bus 12 ' from the farthest from the controller 1 arranged bus participants from in the direction of the control unit 1 is passed through. According to the sketch of 2 sends the last bus participant with it 4 during operation of the second bus 12 ' with his second transmitter 11 to the first recipient 8th of the first bus participant 3 , The first bus participant 3 transfers the data stream for the second bus via its first transmitter 9 to the control unit 1 ,

The following is an initialization procedure for assigning individual addresses to the bus participants 3 . 4 shown (see also 3 ): In a first step is the on the first bus 5 connected bus subscribers 3 . 4 over this bus 5 assigned a first address. This is the same for all bus subscribers. The control unit 1 forgives itself the same address. This assigned individual address can be, for example, a structure counter, which is initially set to the value SZ = 0 in the described embodiment.

The further initialization for address assignment is via the designed as a structure bus bus 12 performed. Every bus participant 3 . 4 including the control unit 1 counts have received the address SZ = 0 in each case equally through the first addressing. In every bus participant 1 . 3 . 4 This obtained structure counter is increased by one counter and then via the second bus 12 transmitted to the downstream in the series arrangement bus subscribers. Thus, the controller transmits 1 to the first bus participant 3 its incremented by a counter structure counter and thus the signal SZ = 1. The first bus participant 3 sends to the downstream second bus subscriber 4 the same structure counter, namely SZ = 1.

The first bus participant 3 coming from the controller 1 over the second bus 12 has received the structure counter SZ = 1, increases this structure counter by one counter and sends again a structure counter, namely SZ = 2 to the downstream bus subscriber 4 , Each bus user retains the address which corresponds to the highest structure counter received by this subscriber. Thus, the controller 1 as the address of the structure counter SZ = 0, the bus subscriber 3 as the address of the structure counter SZ = 1 and the bus subscriber 4 the structure counter SZ = 2 are assigned. These steps will continue until all the bus participants via the structure bus 12 have received an individual address. Is, as in 1 represented, the last bus subscriber, here the bus subscriber 4 over the connecting line 14 with the control unit 1 connected, carried out in this way a response to the control unit 1 in that all bus subscribers have received an address.

The from the upstream in the series arrangement bus subscribers sent to the bus subscriber following in the series arrangement Signal can - like described above - the structure counter as such or merely a signal through which the counter of the the signal receiving bus subscriber increased by one counter becomes.

The The addressing method described above can also be reversed Direction performed be starting from the last in the series arrangement Bus participants towards the control unit.

The need for a connection to the controller 1 even if the first bus 5 is designed bidirectionally. In this case it is possible for each individual bus user to receive his individual address via the first bus 5 a message to the controller 1 sends and thus its initialization, ie the receipt of the individual address indicates. From the totality of these messages receives the control unit 1 the necessary addressing information for the first bus 5 , Similarly, after address assignment via the first bus 5 also device-specific data to the control unit 1 be sent so that the ECU side an evaluation of the individual, to the bus 5 connected devices can be done.

At the in 2 In the exemplary embodiment shown, the method described above is carried out in the reverse order and thus starting from the last bus subscriber, in this case the bus subscriber 4 carried out.

Furthermore, the invention includes a method based on the bus system according to the invention with a first bus 5 and a second bus 12 for the realization of an energy saving operation. For this case, it is assumed by way of example that the first bus subscriber 3 as the device component comprises a light source and the second bus subscriber 4 a switch that can be operated by a user, with the aim of the light source of the first bus device 3 to switch. For a system design according to 1 It is initially assumed that the first bus participant 3 and the second bus participant 4 in sleep mode, but not the controller 1 , Will the switch in the second bus participant 4 switched by a user, the reactivation of the second bus participant takes place 4 from sleep mode to normal operation due to external operation. As a result, on the first bus 5 , which is bidirectional for this case, a message about the switch operation to the control unit 1 forwarded. The controller can not immediately send a message to the first bus user 3 for the adjustment of the illuminance of the light emitting means, since the first bus subscriber 3 still in sleep state. Therefore, via the second bus 12 a message to the receiver of the bus station, in this case the first receiver 8th , delivered. It represents the only component of the first bus participant 3 which must also be queried regularly in sleep mode. With input of the signal on the first receiver 8th the first bus participant reactivates 3 and takes (again) to communicate over the first bus 5 Part and can thus in terms of user request by a control command from the controller 1 caused to switch the bulb accordingly.

If it is assumed for a process alternative that for the energy-saving operation also the control unit 1 in addition to the individual bus subscribers goes into sleep mode, starting from the case described above after the activation of the second bus subscriber 4 due to the switch operation, first a reactivation of the controller 1 be executed. This can in turn via the second bus 12 starting from an externally activated bus subscriber then take place when via the second bus 12 a message to the control unit 1 can be transmitted. In the embodiment of the 1 this succeeds due to the annular topology of the second bus 12 that is, the reactivation message continues over the series arrangement of the bus subscribers on the second bus 12 continue until over the connection to the controller 14 the control unit 1 is reached and can be reactivated. Was during the passage of the previous bus participants along the second bus 12 the bus subscriber to be addressed has not yet been reactivated, then the series arrangement in this case is passed through by the control unit 1 until the corresponding bus subscriber is reached, reactivated and via the first bus 5 is addressable. As shown above, the activation of bus subscribers takes place via the second bus 12 in each case by sending a message to the receiver by the previously activated previous bus subscriber.

The invention may in the context of the following claims are modified, in particular, the shape of the first bus and the second bus can be adapted to the required use. In general, however, the first bus will be characterized by fast communication and by a more complex digital protocol, while the second bus, designed as a structure bus, may be slow and can be designed to be particularly energy efficient in return for the first bus.

1

control unit

2

Signal transmission device

3

first bus device

4

second bus device

5

first bus

6

first Bus connection point

7

second Bus connection point

8th

first receiver

9

first transmitter

10

second receiver

11

second transmitter

12 12 '

second bus

13

communication link

14

connection to the control unit

15

termination point

B, B '

bus system

Claims (11)

Method of operating a first bus ( 5 ) and several bus participants ( 1 . 3 . 4 ) bus system (B, B '), in which the bus subscribers ( 1 . 3 . 4 ) over one of the first bus ( 5 ) separate unidirectional second bus ( 12 . 13 ) are connected in series in a series arrangement, wherein during the initialization of the bus system (B, B ') each bus subscriber ( 1 . 3 . 4 ) in the direction of the operation of the second bus ( 12 . 13 ) a message to the downstream in the series arrangement bus subscribers ( 3 respectively. 4 ), characterized in that - for the initialization of the bus system (B, B ') in a first step uniformly all bus subscribers ( 1 . 3 . 4 ) over the first bus ( 5 ) a first address is transmitted and - in a subsequent step, starting from a first bus subscriber as a control unit ( 1 ) along the row arrangement of the in the second bus ( 12 . 13 ) bus subscribers connected in series ( 1 . 3 . 4 ) of each bus subscriber ( 1 . 3 . 4 ) the received message is processed in such a way that for the respective downstream bus subscribers ( 3 respectively. 4 ) an individual address arises. Method according to claim 1, characterized in that the second bus ( 12 . 13 ) is designed as a structure bus, each bus subscriber ( 1 . 3 . 4 ) has a structure counter and the messages sent in the direction of operation of the second bus transmit counter readings of the structure counters. A method according to claim 2, characterized in that with the transmission of the first address in the bus subscribers ( 1 . 3 . 4 ) the respective structure counter is set with its count to a start value. Method according to claim 3, characterized the value 0 is set as start value. A method according to claim 3 or 4, characterized in that - by a successively connected bus subscriber ( 1 . 3 . 4 ) receive the structure counter of this bus user ( 1 . 3 . 4 ) to the meter reading transmitted in the message; - each bus participant ( 3 . 4 ) retains the received message with the highest count as its individual address; The processing of a received message by the bus users ( 1 . 3 . 4 ) for generating a message for the downstream bus subscriber ( 3 respectively. 4 ) by increasing the current count. Method according to Claim 5, characterized in that the counter steps by which the counter readings of the bus subscribers ( 1 . 3 . 4 ) are incremented in the processing of received messages having a value of 1. Method according to one of claims 1 to 6, characterized in that of the last bus subscriber ( 4 ) in the series arrangement of the bus subscribers connected in series ( 1 . 3 . 4 ) in the second bus ( 12 . 13 ) via a connecting line ( 14 ) an address assignment completion signal to the control unit ( 1 ) of the bus system (B) is transmitted. Method according to one of claims 1 to 7, characterized in that the allocation of the individual address to a bus subscriber ( 3 . 4 ) by a message from the newly addressed bus subscriber ( 3 . 4 ) on the first bus ( 5 ) for the control unit ( 1 ) is shown. Method according to one of claims 1 to 8, characterized in that for performing a power-saving operation of the first bus ( 5 ) the second bus ( 12 . 13 ) also to reactivate sleeping bus subscribers ( 3 . 4 ) and / or a sleeping control unit ( 1 ) serves. A method according to claim 9, characterized in that for reactivating a sleeping bus participant ( 3 . 4 ) of the bus system (B, B ') the control unit ( 1 ) a signal over the second bus ( 12 . 13 ) to at least the receiver of the sleeping, to be activated bus subscriber, so that this the communication link to the first bus ( 5 ). Method according to claim 9 or 10, characterized in that for the reactivation of a sleeping control device ( 1 ) of the bus system (B) an active bus subscriber by means of a signal via the second bus ( 12 . 13 ) and a connection line ( 14 ) all bus subscribers along the series arrangement of consecutively connected bus subscribers ( 3 . 4 ) to the control unit ( 1 ) is activated.