Expansion element for a device in a bus network

Abstract

An extension element (600) for a device (604), suitable for being connected in a linear network having a bus topology, comprising: - a first connection point (401) and a second connection point (402); - a switch (405) connected to the first connection point (401) and to the second connection point (402), so that in a closed state of the switch (405) there is a direct connection between the first connection point (401) and the second connection point (402); in an open state of the switch (405) the direct connection is interrupted; - a read-write connection (605) between a read port of a first interface (407) and a write port of a second interface (502), - a processing unit (406) configured to modify the state of the switch (405) and to change, via the processing unit (406), the impedance in said read-write connection or in a connection between the first interface (407) and the second interface (502), in order to change the state of the extension element (600) from an idle state to a forwarding state.

Description

Technical Field

[0001] This invention generally relates to the control of equipment in entertainment or other facilities. In particular, this invention provides a retrofit solution for systems using conventional RS-485 / DMX512 technology, thereby allowing for more efficient configuration and increased reliability. Background Technology

[0002] In entertainment applications such as festivals, concerts, and artistic performances, specialized facilities are used to control equipment. These devices include, for example, spotlights, loudspeakers, smoke machines, or motors used to drive the movement of decorative elements. Here, the behavior of the equipment is set via a central control element (e.g., a lighting or sound control console), and this control data is transmitted to various devices via a network of communication cables. These facilities are often quite extensive, with hundreds of connected devices.

[0003] Typically, devices are interconnected in a network, with the output port of one device connected to the input port of a subsequent device via a communication cable to form a chain. One end of this chain is then connected to a control console for lights or sounds. Each device has its own controller that drives the device based on received control data, such as providing light of a given color, sound of a given volume, or mechanical movement of a given action.

[0004] In the standard setup of such facilities, the RS-485 standard and the DMX512 protocol are used for network communication. RS-485 is a standard that defines the characteristics associated with the network physical layer. RS-485 uses differential signaling, where information is transmitted as a first voltage signal through a first conductor and as a second inverted voltage signal through a second conductor. Because the receiver only detects the voltage difference between the two conductors, this technique is less sensitive to electromagnetic noise. The RS-485 standard further enables the implementation of networks with a linear bus topology. With such a bus topology, the network has a common line, or "bus," along which data is communicated, and each device is connected to this common line via an interface. Therefore, all data is communicated via the common bus and received by every device in the network. Finally, the RS-485 standard only allows half-duplex communication, meaning that transmission and reception occur on the same signal line, but never simultaneously.

[0005] In professional entertainment facilities utilizing the RS-485 standard, a communication cable with a 3-pin or 5-pin XLR connector is used to connect the output of one device to the input of another; this is known as a "daisy chain." Since the inputs and outputs are directly connected within each device, the aforementioned bus topology is created: a common "bus" is formed on one hand by the communication cables between devices, and on the other hand by the input / output connections within each device. The advantage of this bus topology is that when one device experiences a power failure, the devices further down the chain continue to receive their signals correctly.

[0006] In the standard setup of professional entertainment facilities, the RS-485 standard is used in conjunction with the DMX512 (Digital Multiplexing) protocol. This protocol considers 512 channels, which are shared among devices in the network. Therefore, each device is assigned multiple channels, and each channel is used to control a given function on the device. The number of channels used by each device can vary from device to device. During configuration, each device is assigned a starting address; all devices receive the same data via a common bus, but each device's controller only listens to channels from its assigned starting address. Due to the common bus, each device in the chain receives its control data simultaneously, allowing for synchronous control of all devices.

[0007] The aforementioned conventional solution utilizing the RS-485 standard and DMX512 protocol has been known for over 30 years, but it remains very frequently used in the professional AV market. This conventional solution is also commonly used in applications outside of entertainment, such as controlling lights indicating whether parking spaces are occupied in a parking lot.

[0008] However, the use of this conventional solution comes with several drawbacks. The first drawback involves the configuration of the communication network. Configuration means determining which function of which device will be controlled by which channels. To do this, the corresponding locations of the devices must be mapped, and a starting address must be assigned to each device in the network so that it knows which channels it should listen on. For each new event or performance using a different arrangement, configuration must be done again.

[0009] Broadly speaking, there are two possible configuration methods. In the first method, a starting address is set for each individual device, such as using a row switch or DIP switch on the device. Calculations are often required to determine the correct switch positions, making the configuration complex and error-prone. Furthermore, a diagram needs to be manually drawn, tracking which device is located where in the network and which channels each device should use. Given the scope of specialized facilities, this configuration method is complex, time-consuming, and prone to errors.

[0010] The second configuration option uses the so-called RDM protocol. This protocol allows bidirectional communication via a request-response system. Thus, a list of devices present in the network can be created via a computer on the central control element, with each device identified by a unique ESTA code. During configuration, the central control element sends a request, such as: "Is there a device with a code between 0 and 100?" If multiple devices want to respond, the response is incomprehensible given the shared bus on which all communication takes place. Therefore, the request must be refined, for example: "Is there a device with a code between 0 and 50?" If only one device responds, then that device is identified. This query must continue iteratively until a list with the codes of all connected devices is obtained. Given the need to wait for a response each time and the potential for multiple iterations, this configuration method is also time-consuming. Furthermore, the list of devices can be built automatically in this way, rather than according to the order in which they are connected in the network. Therefore, it is still necessary to manually map the position of each device in the chain.

[0011] Besides the complex and time-consuming configuration, another drawback of conventional solutions involves reliability, and more specifically, defects in the communication cables. In the event of a cable break, there are existing systems that can address this problem: a special function then allows access to many devices in the network via an alternative route. For this, constructing the network as a ring suffices. However, in the event of a short circuit in the cable, all data traffic on the common bus stops due to the bus topology. Therefore, no devices can be controlled. Furthermore, it is impossible to automatically trace the cable where the defect occurred, which wastes a significant amount of time through manual intervention.

[0012] In addition to the conventional RS-485 / DMX512 solution described, Ethernet-based solutions have recently become known. Here, for example, the devices are serially connected, and each device has a switch that determines whether data packets are to be used by the device itself or should be transmitted to downstream devices. A drawback of this solution is that in the event of a power failure in one device, data flow to downstream devices stops. Furthermore, many users still currently have conventional RS-485 / DMX512 solutions, and switching to another type of solution would mean an expensive purchase.

[0013] Finally, known solutions in the prior art use a ring topology and forward data sequentially from one node to the next in the ring. Instead of using a common bus where data is received simultaneously by all nodes, this solution uses serial communication, where data is forwarded from one node to another. An example of this solution can be found in US2016 / 0275783A1. A drawback of this solution is that in the event of a power failure at one of the two nodes, the intermediate node cannot be reached. Furthermore, the solution in US2016 / 0275783A1 involves components controlling fire alarm, fire suppression, or oxygen reduction systems, such as gas sensors or fire extinguishing systems. For such applications, different requirements then apply to the control of recreational facilities. In particular, allowing synchronous control of all equipment in the recreational facility (e.g., changing the color of multiple lights precisely at the same time) is crucial.

[0014] Therefore, a solution is needed in which conventional RS-485 / DMX512 technology can still be used, but with modifications to compensate for deficiencies in configuration and reliability.

[0015] The purpose of this invention is to describe a solution that overcomes one or more deficiencies of the aforementioned prior art solutions. More specifically, the purpose of this invention is to describe a retrofit solution for systems using conventional RS-485 / DMX512 technology, thereby allowing for more efficient configuration and increased reliability. Summary of the Invention

[0016] According to a first aspect of the invention, the above objective is achieved by an extension element for a device as defined in claim 1, wherein the device is adapted to be connected to other devices in a linear network having a bus topology via a first communication cable and a second communication cable, and wherein the extension element comprises:

[0017] - A first connection point and a second connection point, adapted to connect the expansion element to a first communication cable and a second communication cable, respectively;

[0018] - A third connection point, suitable for connecting an expansion element to a control unit included in the device;

[0019] - Switch, connected to the first connection point and the second connection point;

[0020] - The processing unit is connected to the third connection point and is connected to the first and second connection points via a connection that does not include a switch;

[0021] - The first interface and the second interface are respectively adapted for data exchange between the first connection point or the second connection point and the processing unit;

[0022] - The read-write connection between the read port of the first interface and the write port of the second interface, and the write-read connection between the write port of the first interface and the read port of the second interface.

[0023] The processing unit is configured as follows:

[0024] - Modify the state of the switch so that

[0025] ○ When the switch is closed, there is a direct connection between the first connection point and the second connection point. This direct connection does not include the first interface and the second interface, and in the installed state, it forms part of the common bus of the network.

[0026] ○ With the switch on, the connection is directly disconnected;

[0027] - Change the impedance in the connection between the read-write connection or the write-read connection or the first interface and the second interface via the processing unit so as to change the state of the expansion element from an idle state in which there is no data traffic on the read-write and write-read connections to a forwarding state in which there may be data traffic on the read-write or write-read connections.

[0028] In other words, the present invention relates to an extension element for a device adapted to be connected to other devices in a linear network having a bus topology via a first communication cable and a second communication cable. A device is an apparatus designed to perform a specific action. For example, a device is a lamp, spotlight, or "light fixture" designed to generate light, or a loudspeaker designed to generate sound. A device can also be an AV (audio / video) device. Other examples of devices include projectors, cameras, screens, pulleys, movable decorative elements, apparatus for generating special effects such as fire or fog, etc. Typically, such devices form part of a complete facility (e.g., a specialized entertainment facility) with a large number of devices. A device includes electrical or mechanical components, such as actual lamps or loudspeakers, and a control unit. The control unit is a controller or regulator adapted to control various functions on the device based on received control data, such as turning lights on or off, setting desired light intensity or color, desired sound volume, moving decorative elements in a specific manner, etc.

[0029] The device is suitable for connection to other devices in a linear network via a first communication cable and a second communication cable. A linear network is a network in which consecutive devices are connected to each other, with a connection between each pair of consecutive devices at a time. The network may include a serial chain of devices or may form a loop. For example, devices have input ports and output ports, and communication cables connect to the output port of one device and the input port of a subsequent device. Communication cables are cables that allow the transport of data used to control the devices. For example, it is a cable with a 3-pin or 5-pin XLR connector.

[0030] The device is suitable for connection to other devices in a network with a bus topology. A bus topology refers to the existence of a common line or "bus" along which data is communicated, and each device is connected to this line or "bus" via an interface. Data is thus communicated via the common bus and received synchronously by each device in the network. For example, the network uses the RS-485 standard, which involves the physical layer for communication. In this case, data is transported using differential signaling, where information is transmitted as a first voltage signal through a first conductor and as a second inverted voltage signal through a second conductor, and only the voltage difference between the two lines is detected by the receiver. Typically, the network uses a bidirectional bus, thus suitable for half-duplex communication. This means that transmission and reception occur on the same signal line, but never simultaneously.

[0031] Devices connected to the network receive their control data from a central control element. This central control element is, for example, a lighting console, sound console, or computer connected to one side of a serial chain of devices. In this case, the output of the central control element is connected to the input port of the first device via a communication cable. Additional components, such as Ethernet-DMX converters, may also exist between the central control element and the first device. Furthermore, the network may be connected in a loop, with the central control element connected to the first device and the last device in the chain.

[0032] An expansion element is a physical component, such as one implemented as a printed circuit board (PCB). For example, a device may have a housing or enclosure, and the expansion element is arranged within the housing or enclosure of the existing device. In this way, the expansion element forms an addition or physical extension to a device already purchased by the user. The installation of the expansion element allows for retrofitting of existing equipment. In another embodiment, the expansion element is implemented as a separate device with its own housing, and this device can be connected to the device so that they can work together. In this case, the expansion element also allows for retrofitting of existing systems. In yet another embodiment, the expansion element is a component of a new device (i.e., a device that has not been used before). This means that the expansion element is assembled into the new device along with other components. In other words, the expansion element forms part of the new device, and this complete unit is sold to the user. For example, the device includes a PCB on which components corresponding to the design of the expansion element are arranged. In this case, the expansion element present in the new device to be sold allows for a wider range of possibilities compared to conventional equipment.

[0033] The expansion element includes a first connection point and a second connection point adapted to connect the expansion element to a first communication cable and a second communication cable, respectively. Such connection points can be physically designed in various ways. For example, the expansion element is implemented as a printed circuit board (PCB) with connectors provided on it as the first and second connection points. When the expansion element is installed in a device, a connection is then made between such connectors and the device's input / output ports. In this case, communication cables are connected to the device's input and output ports. In another embodiment, the expansion element is implemented as a separate device including two connectors to which communication cables can be connected. Regardless of how the first and second connection points are actually designed, once connected in the network, they allow data exchange to be established between the expansion element and the network. For this purpose, the connection points are customized according to the standards used for communication in the network. For example, the network uses the RS-485 standard, and therefore data exchange via the first and second connection points is conducted in half-duplex communication.

[0034] The expansion element further includes a third connection point adapted to connect the expansion element to the control unit of the device. Typically, a control unit, i.e., a controller or regulator, is already present in existing devices. The expansion element, then arranged in such a device, can be connected to the control unit via the third connection point. In another embodiment, a new device is assembled, in which the control unit, the expansion element, and the connections between them are installed.

[0035] The expansion element includes a switch connected to a first connection point and a second connection point. A switch is a component that can interrupt current in the open state. For example, it is a relay, where the mechanical switch is operated by an electromagnet. In the closed state of the switch, a direct connection exists between the first and second connection points. For example, when an expansion element is installed in a device, the existing connection between the input and output ports is broken, and a new direct connection is formed through the switch of the expansion element.

[0036] The extended elements further include a processing unit. The processing unit is, for example, a microprocessor, chip, or CPU. The processing unit can be programmed according to a specific type of logic to interpret received data and generate a given output based on that data.

[0037] The processing unit connects to a third connection point. Through this route, the processing unit can communicate with the control unit, for example, to transmit settings to the control unit or request data from the device. Optionally, an interface exists between the processing unit and the third connection point. In one embodiment, the control unit is designed for the RS-485 standard, while the processing unit is designed for another standard, such as an asynchronous serial bus (UART) or other board-level serial buses (such as I2C and SPI). In another embodiment, the RS-232 standard can be used at the processing unit level. The interface then allows communication between the two components. In yet another embodiment, the processing unit and the control unit use the same standard, and there is no interface at the location of the third connection point.

[0038] The processing unit is also connected to both the first and second connection points, each via a connection excluding the switch. Therefore, the processing unit is located in the first branch of the common bus, situated on one side of the switch. Data received via the first connection point can thus be transmitted to the processing unit without passing through the switch. A connection also exists between the second connection point and the processing unit, where this connection does not include the switch. Therefore, the common bus has two branches, located on either side of the switch. Data sent by the processing unit can thus reach the second connection point without passing through the switch. A first interface exists in the first branch leading to one side of the switch, and a second interface exists in the second branch leading to the other side of the switch. This interface allows the bus standard (e.g., RS-485) to be converted to the processing unit's standard (e.g., asynchronous serial bus (UART) or other board-level serial buses (such as I2C and SPI)). When the switch is closed, data flow occurs through the common bus. The processing unit branches off from this bus to receive all data transmitted on the bus. Data for the device can be transmitted to the control unit. When the switch is open, no data flow is possible on the common bus. However, communication between the processing unit and directly connected adjacent devices or directly connected central control elements remains possible via the first and / or second connection points of the expansion element. For example, status data or configuration messages can be exchanged via this route.

[0039] The expansion element further includes:

[0040] - The read-write connection between the read port of the first interface and the write port of the second interface.

[0041] - Write-read connection between the write port of the first interface and the read port of the second interface.

[0042] This means that the expansion element includes a first interface with read and write ports, and a second interface with read and write ports. The first and second interfaces are each located in a branch on either side of the switch and are each connected to the processing unit. A connection exists between the read port of the first interface and the write port of the second interface, referred to as a read-write connection. Similarly, a connection exists between the write port of the first interface and the read port of the second interface, referred to as a write-read connection.

[0043] The processing unit is configured to modify the state of a switch. For example, the switch is a relay, and the processing unit can adjust the power supply to the electromagnet in the relay. The processing unit also includes a specific type of logic that determines when the switch state should be modified. The change of switch state can be made, for example, based on a request from the central control element. In another embodiment, the processing unit can actively change the switch state, for example, based on received measurements. In the closed state of the switch, a direct connection exists between the first and second connection points, which, in the installed state, forms part of the network's common bus. This means that when expansion elements are connected to the network, the network's common bus is formed, on the one hand, by communication cables, and on the other hand, by the direct connection between the first and second connection points in each expansion element. In the closed state of all switches, the central control element communicates with the network via this common bus. The data transmitted here is received synchronously by all devices. The system then operates in bus mode, similar to a conventional solution using the RS-485 standard and the DMX512 protocol. However, in the open state of the switch, the direct connection between the first and second connection points is broken. At that moment, the network's common bus is interrupted, and no more data traffic is possible on this bus.

[0044] The processing unit is further configured to change the state of the extended element from an idle state to a forwarding state, and vice versa. In the idle state, no data traffic is possible via read-write or write-read connections. In the forwarding state, data traffic is possible via both read-write and write-read connections. The state change is performed by the processing unit, which initiates an impedance change. This can involve the impedance in the read-write connection, or the impedance in the write-read connection, or the impedance in the connection between the first interface and the processing unit, or the impedance in the connection between the second interface and the processing unit. This means that, based on the output generated by the processing unit, the relative impedance is changed to force data to flow along the preferred path (i.e., the path with the lowest impedance).

[0045] Various embodiments are possible for implementing state changes. In a first embodiment, a component with adjustable resistance (e.g., a variable resistor or transistor) is placed in the read-write and write-read connections, thereby allowing changes in the impedance of the respective read-write / write-read connection. In a second embodiment, state changes are triggered by changing the impedance at the first and second interface levels without requiring additional adjustable components between the two interfaces. For example, adjustable impedance in the read-write / write-read connection can be obtained by adjusting the impedance of a specific pin present in the interface. For example, pins of an RS-485 driver can be placed in a high or low impedance state, or can be connected or disconnected to change the impedance. In a third embodiment, the impedance in the connection between the first interface and the processing unit, or the impedance in the connection between the second interface and the processing unit, is changed. For example, pins of a microprocessor can be placed in a low or high impedance state.

[0046] The extension element according to the invention allows for control of devices in a network in either bus or serial mode, offering advantages in terms of synchronization, reliability, and configuration efficiency. This will be explained in detail below.

[0047] First, the expansion elements allow for network control in bus mode. In fact, when all the switches of the expansion elements included in the network are closed, control data can be transmitted via the network's common bus, just as in a conventional RS-485 / DMX512 solution. Therefore, all devices receive control data simultaneously, allowing for synchronized control of all devices. For example, the colors of multiple lights in the network can change precisely at the same time. Furthermore, with the presence of switches controllable via the processing unit, it is possible to interrupt the network's common bus at specific locations. Thus, with the expansion elements, it is possible to interrupt the bus at carefully selected locations, thereby segmenting the chain as desired. This provides various possibilities, resulting in advantages over conventional RS-485 / DMX512 solutions.

[0048] First, when operating in bus mode, it is possible to turn on a switch in one of the network's extension elements. In this way, the network's public bus is interrupted at one point. Data flow on the bus is still possible until the point of interruption; one could say the bus can be shortened. This creates the possibility of executing the following sequence in the configuration, where the bus first reaches only the first device, then the first and second devices, and so on. In this way, it is possible to identify the first device in the first step, then the second device, and so on. Therefore, not only can a list of connected devices be established, but also the order in which the devices are connected in the network can be established. Thus, there is no longer a need to manually map which device is in which position in the chain. Once the devices have been identified and their order has been determined, each device can further be individually addressed by the central control element to assign a starting address. The entire configuration can be carried out automatically in this way. This contributes to a more efficient and less error-prone system configuration.

[0049] A second possibility arising from the use of expansion elements is to temporarily and completely disconnect the bus by turning on a switch on each expansion element. Thus, the processing unit of the expansion element appears to be decoupled from the bus. One-to-one communication is still possible between a device and a directly connected neighboring device, or between a device and a directly connected central control element. Communication then proceeds through the first and / or second connection points of the expansion elements. In a pure bus topology, such one-to-one communication, where a device communicates only with its neighbor, is impossible. This creates the possibility of configuring each device to determine the sequence of its neighbors. From this data, the central control element can again infer the order of the connected devices. Therefore, this provides an alternative method for automatically determining the order. Again, this contributes to a more efficient and less error-prone configuration.

[0050] A third possibility arising from the use of the expansion element is that, in bus mode operation, two switches can be opened in a targeted manner to isolate a section of cable from the bus. During normal operation, data flow proceeds through the bus with all switches closed. However, if a short circuit occurs in the cable, the two switches in the processing units to the left and right of the defect open. In this way, data flow on the bus becomes possible again, except for the defective isolated cable. All devices can then reach the bus again, although some may pass through other parts of the loop. Furthermore, it is possible to detect when a defect occurs via the processing units of the expansion element, for example, via voltage measurements at interfaces with a first or second connection point. In this way, short circuits are automatically detected, and data flow is automatically restored via the opening of the selected switches. This increases system reliability and reduces the need for manual intervention to locate defects.

[0051] In summary, this invention allows for bus-mode network control, while switches provide the possibility of interrupting the bus. Furthermore, intelligence is introduced into the device via a processing unit, allowing control of switches and the exchange of desired data with, for example, adjacent devices or control units. This can be adopted in a variety of applications, allowing for more efficient configuration and increased reliability. Moreover, the closure of all switches allows normal operation to be maintained as in conventional systems, data flow on the common bus results in synchronized control, and is not interrupted in the event of a power failure within the device.

[0052] Furthermore, the expansion elements allow for serial network control. This serial operation is achieved by disconnecting the bus while keeping each expansion element switched on while controlling the device. When transmitting control data to the device, the expansion element is in a forwarding state. Therefore, depending on the transmission direction, data flow occurs via a direct read-write or write-read connection to each expansion element. In this case, instead of a bus topology, a serial topology is used, where consecutive interfaces transmit data to each other. Serial mode or serial topology can also be referred to as cascaded topology or peer-to-peer communication. The advantage of this topology compared to a bus topology is that in the event of a cable short circuit, not all data flow stops, and data flow can still reach the device by redirection. The disadvantage of this topology is that in the event of a power failure in either of the two devices, the intermediate device cannot be reached. Therefore, in the event of an accidental power failure in a device, the switch can be temporarily closed again.

[0053] Furthermore, when operating in serial mode, the extension element still allows for synchronous control of connected devices in the network. In fact, since control data is only sent after the extension element is placed in forwarding mode, it is transmitted solely through passive connections. These passive connections are purely direct connections, or consist only of passive components. Therefore, data is not transmitted through active components, which introduce some logic or intelligence that can introduce delays. Transmission via passive connections allows for very fast transmission of control data across all devices without any delays introduced by various nodes. Therefore, even when operating in serial mode, it is still possible to synchronously control all devices, where all devices receive control data almost simultaneously.

[0054] Furthermore, in serial mode, the switch of each expansion element can remain open throughout the configuration phase. In fact, neighbor determination, required to determine the order of devices, can now be performed by temporarily opening read-write and write-read connections, thus placing the expansion elements in an idle state. Adjusting impedance to open and close those connections allows for faster operation than when neighbor determination is performed via opening and closing switches. In the latter approach, a specific waiting time required for stabilization must be applied after each switch closure. Otherwise, noise appearing on the line immediately after a switch closure would be incorrectly interpreted as a data signal. Conversely, this waiting time is unnecessary when changing the state of an expansion element by adjusting impedance. Moreover, an expansion element can be placed in an idle state again as soon as it detects the end of control data transmission. In this way, devices can receive messages from the central control element at any time, even when there is no control data exchange, such as for requesting status according to the RDM protocol. Here, the use of adjustable impedance allows for flexible changes in state from closed to open and vice versa, without waiting for any stabilization period.

[0055] Finally, this invention allows users to continue using their existing conventional equipment and cables, and the aforementioned advantages can be achieved through simple modifications. The modifications only require the inexpensive purchase of a suitable number of expansion components, which are then simply installed in or on the equipment.

[0056] Optionally, according to claim 2, the expansion element is adapted to be installed in the housing of the device, and the first connection point and the second connection point are respectively adapted to be connected to the input port and output port included in the housing of the device in the installed state. For example, the device is one previously used in a conventional RS-485 / DM512 setup. The device has a housing or enclosure in which the control unit and technology for generating light, sound, etc., are located. The device also has input and output ports adapted to be connected to with communication cables. To retrofit such a device, the housing must be opened, and then the expansion element must be installed. The expansion element then becomes an accessory to the existing device. Within the device, the connection existing between the input and output ports is removed, and a connection is established between the input port and the first connection point of the expansion element, and between the output port and the second connection point of the expansion element. In another embodiment, the device is a new device that has not been used before, and the expansion element is arranged in the housing when installing the new device. In both embodiments, the expansion element is located inside the device after installation. The advantage of doing so is that the device can be connected to the network as before by connecting the communication cable to the input and output ports.

[0057] Optionally, according to claim 3, the processing unit is configured as follows:

[0058] - Interpret the control data and configuration settings received via the first connection point, and transmit the control data and configuration settings to the control unit via the third connection point;

[0059] - Request one or more features of the device via a third connection point and transmit the feature via a first connection point.

[0060] This means that the processing unit includes a specific type of logic that interprets received data and generates a given output based on it. Therefore, the processing unit is configured to interpret control data and transmit it to the control unit. Control data refers to data used for the normal control of functions on the device, such as turning a light on or off, setting a desired light intensity or color, a desired sound volume, moving decorative elements in a specific manner, etc. When the processing unit receives control data, it can decide to transmit the control data to the control unit only if the data is intended for use with the corresponding device. In another embodiment, the processing unit may still transmit control data, and the control unit itself determines whether the data is intended for use with the device. The processing unit is further configured to transmit configuration settings to the control unit. For example, these could be settings such as an assigned starting address sent by a central control element. The processing unit is further configured to request one or more characteristics of the device from the control unit. For example, these could be the device's identifier or ID, or specific data (such as the duration a light has been on). These requested characteristics can be sent by the processing unit to the central control element.

[0061] Optionally, according to claim 4, the extension element is adapted to control the device according to a protocol, wherein the protocol defines the composition of a data frame including a sequence of control data intended for use by successive devices in the network, and an interruption period preceding the sequence of control data. The protocol refers to a communication protocol that defines a set of rules for communication in a network. In an embodiment, the protocol is the DMX512 protocol, a protocol commonly used to control devices (such as lights or smoke machines) in entertainment facilities. The protocol defines how the data frame is composed, i.e., which predefined sequence is used each time control data is sent to a device. The data frame includes an interruption period preceding a series of control data. The control data is actual data, for example, used to turn on a light or change its color. For example, in DMX512, the sequence of control data consists of 512 data slots, corresponding to the 512 channels available in DMX. Each device is assigned 512 channels, and each channel is used to control a given function on the device. The first part of the data frame includes the interruption period. The interruption period refers to a certain waiting time, i.e., a certain period of time during which the data frame has started but the actual control data has not yet been sent. For example, DMX512 specifies "BREAK" in the first part of the data frame, followed by "MARK AFTER BREAK".

[0062] Combining the extended element of this invention with a protocol that specifies an interrupt period in the data frame allows for highly accurate synchronization when controlling multiple devices simultaneously. In fact, when the extended element is used in serial mode, it is typically idle when no control data is being transmitted, allowing devices to exchange messages with a central control element, for example, according to RDM. Once the extended element detects the start of a data frame, its state changes to a forwarding state, allowing direct transmission via read-write or write-read connections. Each extended element in the chain will require some time to place its read-write / write-read connection into this forwarding state. By including an interrupt period at the beginning of the data frame, all extended elements in the chain are placed into the forwarding state when the first extended element in the chain begins receiving the actual sequence of control data. Therefore, the actual control data is transmitted very quickly through successive extended elements, each time using a direct read-write / write-read connection. Since the extended element does not introduce delay when forwarding the actual control data, each device in the chain receives the control sequence at almost the same time. In this way, highly accurate synchronization is achieved between multiple devices in the chain. For example, each light in the chain will change color at exactly the same time. Therefore, a serial-type topology can be used while still obtaining the same synchronous control as when using a classic bus topology.

[0063] Optionally, according to claim 5, the processing unit is configured to change its state from idle to forwarding at the start of a data frame and to change its state from forwarding to idle at the end of a data frame. This means that when the processing unit detects the start of a data frame, it adjusts the selected impedance to place the extension element in the forwarding state, thereby enabling direct transmission via the corresponding read-write or write-read connection. Depending on the direction of the data flow, a read-write connection or a write-read connection will be used. This allows direct transmission via the corresponding read-write or write-read connection. When the extension element detects the end of a data frame, it is returned to the idle state. This allows the device to exchange messages with a central control panel, for example, according to the RDM protocol. For example, the central control element can request the actual temperature of devices in the network. In an embodiment, the start of a data frame is detected whenever a common bus existing between successive devices becomes active. Bus activity means that data will be sent by the central control element, thereby triggering the RS-485 driver in the first / second interface of the extension element to generate a balancing signal according to RS-485. For example, a transition from a flag level to an interrupt level can be detected to indicate that the bus has become active. Since the processing unit of the extension element will detect this change on the first / second interface, this will trigger the processing unit to put the extension element into forwarding mode.

[0064] Optionally, according to claim 6, the processing unit includes a data tracker configured to actively follow data frames as they are transmitted via the read-write connection or the write-read connection, and to detect the end of a data frame based on the data frame composition defined by the protocol. This means that when data frames are transmitted via a direct read-write / write-read connection, the processing unit continuously reads the data that passes through. For this purpose, the processing unit includes a data tracker, which may also be referred to as a data parser or protocol follower. The processing unit can be programmed to know the standard frame composition defined in the protocol used. In this way, by actively tracking data frames, the processing unit knows when a data frame ends. For example, when using the DMX512 protocol, the processing unit detects the end of a data frame when the control sequence corresponding to the 512 channels passes. In this way, by actively tracking data frames as defined by the rules of the specified protocol, a very flexible way to detect the end of a data frame is obtained, and thus the extension element is switched from the forwarding state to the idle state. In fact, even when the duration for transmitting control data cannot be predicted, the processing unit programmed according to the specified rules of the protocol can always detect the end of a frame. This method can be used in conjunction with any type of protocol.

[0065] Optionally, according to claim 7, the processing unit is configured to identify neighboring devices by successively turning on switches, sending requests to neighboring devices via a second connection point, and receiving responses including identifiers of the neighboring devices. This means that the processing unit includes a specific type of logic that allows such a sequence to be executed. This can be used when the network is controlled in bus mode, but for initial configuration purposes, the corresponding switches can be turned on to allow the central control element to determine the order of successive devices in the network.

[0066] Further optionally, according to claim 7, the processing unit is configured to identify a neighboring device by successively bringing the expansion element into an idle state while the switch is in the open state, sending a request to the neighboring device via the second connection point, and receiving a response including the identifier of the neighboring device. This means that the processing unit includes a specific type of logic that allows such a sequence to be executed. This can be used when the network is controlled in serial mode, but for initial configuration purposes, the corresponding read-write / write-read connections can be disabled to allow the central control element to determine the order of successive devices in the network.

[0067] Optionally, according to claim 8, the processing unit is configured to detect defects in the second and first communication cables respectively by monitoring the second and first interfaces respectively, and upon detecting an anomaly, opening a switch and sending error messages via the first and second interfaces respectively. This can be used when the network is controlled in bus mode, but requires opening the selected switch to isolate the defective cable. A defect in the communication cable is, for example, a short circuit in the cable. The defect in the cable connected to the second connection point is detected by monitoring the second interface. The defect in the cable connected to the first connection point is detected by monitoring the first interface. Monitoring can be performed in various ways. For example, communication is via differential signaling, and a non-zero voltage difference between the two signal lines is indicated when a defect occurs. In another embodiment, the read and write ports of both interfaces are used to detect the defect.

[0068] Furthermore, the processing unit is configured to activate a switch upon detecting an anomaly. Activating the switch interrupts the bus at this point. Therefore, the section of the bus where the faulty cable is located cannot have bus traffic, but another section of the bus still has traffic. Error messages can also be sent by the processing unit to the central control element via this last section of the bus. In this way, it is possible to automatically detect which cable is defective. Furthermore, data traffic can be restored. In fact, both extension elements located on either side of the defective cable will detect the defect and activate their switches. In this way, the defective cable is isolated from the bus, and the bus can be used again for data traffic along either side. This leads to increased reliability of the solution.

[0069] According to a second aspect of the invention, a device as defined in claim 9 is provided, wherein the device is adapted to be connected to other devices in a linear network having a bus topology via a first communication cable and a second communication cable, and the device comprises:

[0070] - Electrical and / or mechanical components;

[0071] - A control unit suitable for controlling electrical or mechanical components;

[0072] - An extension element according to a first aspect of the invention, wherein a third connection point of the extension element is connected to a control unit.

[0073] The network, bus topology, communication cables, and devices are defined as described above. This device is suitable for connection to other devices in a linear network with a bus topology via a first communication cable and a second communication cable. For example, the device has input ports and output ports, and the communication cables connect to the output port of one device and the input port of a subsequent device. This device is suitable for connection to other devices in a network with a bus topology.

[0074] The device includes electrical and / or mechanical components, such as lights, speakers, motors for causing specific movements, etc. The device further includes a control unit suitable for controlling the electrical or mechanical components. The control unit is a controller or regulator suitable for controlling various functions on the device based on received control data, such as turning lights on or off, setting desired light intensity or color, desired sound volume, moving decorative elements in a specific manner, etc.

[0075] The expansion element is implemented according to one of the above embodiments. The expansion element is a physical component, such as a printed circuit board (PCB). For example, the device has a housing or enclosure, and the expansion element is arranged within the housing of the existing device. In another embodiment, the expansion element is implemented as a separate device with its own housing, and this device can be connected to the existing device so that they can work together and form a new device. In yet another embodiment, the expansion element is a component of a newly assembled device (i.e., a previously unused device). For example, the new device includes a PCB on which elements corresponding to the design of the expansion element are arranged.

[0076] The third connection point of the expansion element is connected to the control unit. In one embodiment, the first connection point of the expansion element is connected to the input port of the device, and the second connection point is connected to the output port of the device.

[0077] According to a third aspect of the invention, a system for controlling a network of devices as defined in claim 10 is provided, wherein the system comprises:

[0078] -One or more devices according to the second aspect of the invention;

[0079] - Central control element;

[0080] - One or more communication cables, wherein each communication cable connects two devices to each other or connects one device to a central control element, wherein the central control element is configured to transmit data to and receive data from the network.

[0081] The system therefore includes one or more devices as defined above, one or more communication cables as defined above, and a central control element. These devices are interconnected using the communication cables to form a chain. The first device in the chain is connected to the central control element. The central control element is, for example, a light control console, a sound control console, or a computer. Additional components, such as Ethernet-DMX converters, may also exist between the central control element and the first device. Furthermore, the network may be connected in a loop, with the central control element connected to the first device in the chain and the last device in the chain. The central control element is configured to send data to and receive data from the network. Various types of data are possible, such as control data, identification data, characteristics, configuration settings, messages, requests, etc. According to one of the embodiments defined above, each device included in the system includes an extension element. The extension elements allow control of the network in either bus mode or serial mode. In fact, when the switch of each extension element is closed, control data can be sent via the network's common bus. When the switch of each extension element is open, control data can be sent via a direct read-write / write-read connection present in each extension element after the extension element is placed in a forwarding state.

[0082] Optionally, the central control element includes a topology module configured to determine the order of devices in the network by sequentially performing the following operations:

[0083] - In the closed state of the switch in each device, a command is transmitted via the common bus to open the switch;

[0084] - Send a request that successively returns an identifier, closes a switch, and no longer responds if there are subsequent requests.

[0085] - And repeat this request until each device receives the identifier.

[0086] This can be used when the network is controlled in bus mode, but for configuration purposes, the switches are temporarily turned on to determine the order of devices in the network. Determining the order of devices in the network means identifying which device is the first connected in the chain, which is the second connected to the first device, and so on. The central control element includes a topology module, which makes it possible to determine this order of devices by executing a specific sequence. This sequence is based on successively turning on various switches and identifying the corresponding device each time. In this way, the order can be determined automatically. This contributes to more efficient and less error-prone system configuration.

[0087] Optionally, according to claim 11, the central control element includes a topology module configured to determine the order of devices in the network by sequentially performing the following operations:

[0088] - Transmit commands that enable each device's extension elements to identify neighboring devices;

[0089] - Request the device identifier and the identifiers of identified neighboring devices from each device. This relates to a second possible embodiment of the topology module, used during configuration, while normal network control is performed in bus mode. The topology module allows the order of connected devices in the network to be determined during initial configuration. For this, the network must include devices with extended elements suitable for identifying neighboring devices. The topology module makes it possible to determine this order of devices by executing a specific sequence. This sequence is based on each individual device that identifies neighboring devices. In this way, the determination of the order can be automated, which contributes to more efficient and error-free system configuration. This method of determining the order is also faster than the method described in the previous embodiments, as it does not have to wait for a response from the network each time.

[0090] Optionally, according to claim 12, the central control element and devices are connected in a loop, and the central control element includes a self-healing module configured to identify a defective communication cable and adjust data flow accordingly upon receiving an error message from one of the devices. A loop refers to a network in which the central control element is connected to the first device and the last device in a chain. The central control element includes a self-healing module by means of which data flow can be restored when the network is controlled in bus mode in the event of a defect (e.g., a short circuit) in the communication cable. The network must include devices with extension elements adapted to detect defects in the communication cable. Upon detection of an anomaly, the switch of the extension element on either side of the defective cable is turned on, and an error message is sent to the central control element. The central control element will then adjust the data flow accordingly. For example, one part of the chain arrives by sending data from the central control element to the first device, the second device, etc., while another part of the chain arrives by sending data from the central control element to the last device, the penultimate device, and so on. In this way, data flow on the bus will be automatically restored, resulting in increased reliability of the solution.

[0091] Optionally, the central control element includes a configuration module configured to transmit configuration settings to one or more devices. For example, after identifying the connected devices and their order, a message addressing the device is sent, where a starting address is assigned to the device. The entire configuration process can be automated in this manner.

[0092] According to a fourth aspect of the invention, a method for communication in a network of devices as defined in claim 13 is provided, wherein the devices are interconnected via a first communication cable and a second communication cable, wherein the network has a linear bus topology, and wherein the method comprises:

[0093] - Each device provides an expansion element, including: a first connection point, a second connection point, and a third connection point; a switch connected to the first and second connection points; a processing unit connected to the third connection point and to the first and / or second connection points via a connection excluding the switch; a first interface and a second interface adapted for data exchange between the first and second connection points and the processing unit, respectively; a read-write connection between the read port of the first interface and the write port of the second interface; and a write-read connection between the write port of the first interface and the read port of the second interface.

[0094] - Connect the first connection point and the second connection point to the first communication cable and the second communication cable respectively;

[0095] - Connect the third connection point to the control unit included in each device;

[0096] - The processing unit closes the switch, creating a direct connection between the first connection point and the second connection point, which forms part of the network's common bus, thereby controlling the network in bus mode;

[0097] - The processing unit opens a switch, interrupting this direct connection, thereby controlling the network in serial mode.

[0098] - In serial mode, the processing unit changes the impedance in the connection between the read-write connection and / or the write-read connection and / or the first interface and the second interface via the processing unit, thereby changing the state of the expansion element from an idle state in which there is no data traffic on the read-write and write-read connections to a forwarding state in which there may be data traffic on the read-write or write-read connections.

[0099] Optionally, according to claim 14, the method further includes:

[0100] - Control the network in serial mode;

[0101] - When the extension element of the successor device detects the start of a data frame: put the extension element into the forwarding state;

[0102] - Transmit data frames via read-write or write-read connections of successive devices;

[0103] - When the extension element of the successive device detects the end of a data frame: put the extension element into an idle state.

[0104] This means the network is controlled in serial mode, and all extension elements are thus switched on. Upon detecting the start of a data frame, each extension element is placed in forwarding state, allowing direct connections via successive read-write or write-read connections. Upon detecting the end of a data frame, each extension element is returned to idle state, thus blocking data traffic through read-write / write-read connections of the extension element.

[0105] Optionally, according to claim 15, the interruption period of the data frame ensures that the time it takes for the extended elements of successive devices to enter the forwarding state is less than the interruption period. This means that the interruption period included in the data frame allows all extended elements in the chain to be placed in the forwarding state. In other words, when the first device begins reading actual control data, the last device in the chain has just switched to the forwarding state. This means that the interruption period in the data frame needs to be aligned with the time required to switch the extended element from idle to the forwarding state. In an embodiment, the interruption period may have a standard duration as defined in a standard protocol, such as the standard duration of "BREAK" in the DMX512 protocol. In that case, it is advantageous to use an interruption period already defined by the protocol standard. In another embodiment, the duration of the interruption period can be specifically selected to meet the requirement of timely switching of the extended element to the forwarding state. Attached Figure Description

[0106] Figure 1 The entertainment facility, including lights and a light control console, is shown.

[0107] Figure 2 schematically illustrates a conventional RS-485 / DMX512 solution known in the prior art.

[0108] Figure 3 The use of the extension element according to the invention in a system for control facilities is illustrated schematically.

[0109] Figure 4 An extension element according to an embodiment of the invention is schematically shown, and Figure 5 The use of this extension element within the device is illustrated.

[0110] Figure 6 The use of an extension element in a system according to an embodiment of the present invention is illustrated, wherein a common bus is used for data traffic, thereby controlling the network in bus mode.

[0111] Figure 7 The use of expansion elements in a system according to an embodiment of the present invention is illustrated, wherein the connection between two interfaces on each expansion element is used for data traffic, thereby controlling the network in serial mode.

[0112] Figure 8An extended element in a forwarding state is schematically shown according to an embodiment of the present invention.

[0113] Figure 9 An extension element in an idle state is schematically shown according to an embodiment of the present invention.

[0114] Figure 10 A flowchart of an embodiment of the present invention is provided, illustrating a decision tree for switching an extension element from an idle state to a forwarding state and vice versa.

[0115] Figure 11 The composition of a data frame is shown.

[0116] Figure 12 An example is shown of how a change between an idle state and a forwarding state can be achieved by means of changing the relative impedance according to an embodiment of the present invention.

[0117] Figure 13 The operation of a topology module according to an embodiment of the present invention is illustrated, wherein the order is determined in a first sequential manner.

[0118] Figure 14 The operation of a topology module according to an embodiment of the present invention is illustrated, wherein the determination of the order is performed in a second manner using neighbor determination.

[0119] Figure 15 The operation of a self-healing module with anomaly detection according to a possible embodiment of the present invention is illustrated.

[0120] Figure 16 An anomaly detection via an extended element is illustrated according to another embodiment of the present invention. Detailed Implementation

[0121] Figure 1 A professional entertainment facility is illustrated, in which device 100 is controlled by a central control element 105. In the illustrated embodiment, device 100 is a spotlight, and the central control element 105 is a light control console. In the illustrated embodiment, the RS-485 standard and the DMX512 protocol are used. Given that the standard limits DMX to 512 channels, in some cases, a single DMX controller is insufficient to connect all connected devices 100. In this case, so-called DMX domains 107 are used, which are parallel DMX lines used simultaneously. In the illustrated embodiment, DMX512 signals are transmitted via Ethernet between the console 105 and the Ethernet-DMX converter 106. Here, multiple DMX domains are transmitted through a single cable. The cables for the various domains 107 then exit the Ethernet-DMX converter 106.

[0122] Within each DMX domain 107, devices 100 are chained together by connecting the output port 102 of one device to the input port 101 of a subsequent device. For this purpose, communication cables 101, 102 are used, such as XLR connectors with 3 or 5 pins. The output port 102 and the input port 101 are located within the housing 108 of device 100, visible only from the outside of device 100. Figure 1 The representation can be either a conventional RS-485 / DMX512 solution known in the prior art, or a solution in which an extension element is integrated according to the present invention. This is shown in Figure 2 and Figure 3 It is shown in the figure.

[0123] Figure 2 illustrates a system based on a conventional RS-485 / DMX512 solution known from the prior art. Devices 200 are controlled by a central control element 207 and connected to each other via communication cables 205 and 206. Each device 200 includes a controller 203 and a lamp 204. Input ports 201 and output ports 202 in devices 200 are directly connected to each other, see 208. In this way, a linear network with a bus topology is created, where the common bus of the network is formed by the communication cables 205 and 206 and the direct connection 208 in each device 200. Data transmitted by the central control element 207 is received by each device 200.

[0124] Figure 3 A system using an expansion element 300 according to an embodiment of the present invention is illustrated. Devices 301 are controlled by a central control element 302. Each device 301 includes a control unit 203 (e.g., a controller or regulator) and electrical components 204 (e.g., a lamp 204). Each device 301 further includes an input port 201 and an output port 202. A first communication cable 205 and a second communication cable 206 allow devices 301 to connect to adjacent devices 301. Communication cables 205, 206 have, for example, 3-pin or 5-pin XLR connectors. In the illustrated embodiment, the expansion element 300 is integrated into device 301. For example, the expansion element 300 is implemented as an assembled printed circuit board, and it is arranged within a housing 108 of device 301. In this case, it can be an existing device suitable for use in a conventional RS-485 / DMX512 solution. In this case, the installation of the expansion element 300 is performed by opening housing 108, disconnecting direct connection 208, installing the expansion element 300, and connecting it to the input port 201 and output port 202. Furthermore, the extension element 300 is connected to the control unit 203. In other embodiments, the extension element 300 forms part of the new device 301, or the extension element 300 is implemented as a detachable device that can be connected to the device.

[0125] Figure 4An embodiment of the extension element 600 is shown, while Figure 5 An expansion element 600 integrated within a device 604 is shown. Device 604 includes a control unit 203, a lamp 204, an input port 201, and an output port 202. Device 604 is connected to other devices via a first communication cable 205 and a second communication cable 206. The expansion element 600 includes a first connection point 401, a second connection point 402, and a third connection point 403. Connection points 401, 402, and 403 are implemented, for example, as connectors arranged on a printed circuit board. In the illustrated embodiment, after the expansion element 600 is installed in device 604, the first connection point 401 is connected to the input port 201, and the second connection point 402 is connected to the output port 202. Furthermore, the third connection point is connected to the control unit 203.

[0126] The expansion element 600 further includes a switch 405, such as a relay. Switch 405 is connected to a first connection point 401 and a second connection point 402 via connections 409 and 410. In the closed state of the switch, a direct connection exists between the first connection point 401 and the second connection point 402 formed by connections 409, 410 and switch 405. When device 404 is connected in network 303, the closed switch 405, together with communication cables 205, 206, forms part of the network's common bus. In the open state of switch 405, the direct connection 409-410 between the first connection point 401 and the second connection point 402 is interrupted.

[0127] The expansion element 600 further includes a processing unit 406, such as a microprocessor. The processing unit 406 is connected to a third connection point 403. In the illustrated embodiment, an interface 411 exists between the processing unit 406 and the third connection point 403; for example, interface 411 allows communication between the RS-485 standard on the control unit 203 side and another standard on the microprocessor 406 side. This other standard is, for example, an asynchronous serial bus (UART) or other board-level serial buses (such as I2C and SPI). In this embodiment, the RS-232 standard may be used at the processing unit level. The processing unit 406 is also connected to the first connection point via connections 409-408, excluding switch 405. The processing unit is thus located in branch 408 of the common bus 409-410, here to the left of switch 405. In the illustrated embodiment, an interface 407 exists from the RS-485 standard of the bus to the RS-232 standard of the microprocessor 406. Similarly, connections 501-410 exist between processing unit 406 and second connection point 402, where this connection does not include switch 405. Therefore, at locations on either side of switch 405, there are two branches 408 and 501 to the common bus 409-410. Each branch 408, 501 contains an interface: a first interface 407 and a second interface 502. Processing unit 406 is configured to modify the state of switch 405, as schematically represented by 412.

[0128] Figure 4 The diagram further illustrates that the first interface 407 has a read port indicated by "R1" and a write port indicated by "W1". The second interface 502 has a read port indicated by "R2" and a write port indicated by "W2". A connection 605, referred to as read-write connection 605, exists between the read port "R1" of the first interface 407 and the write port "W2" of the second interface 502. The processing unit 406 is configured to change the state of the expansion element 600, as symbolically indicated by the dashed lines from the processing unit 406 to the read-write and write-read connections 601 and 605. Specifically, the expansion element 600 can be placed in a forwarding state, where data traffic will occur through either read-write connection 605 or write-read connection 601. On the other hand, the expansion element 600 can be placed in an idle state, where no data traffic occurs on either read-write connection 605 or write-read connection 601.

[0129] The diagram below illustrates how the expansion element 600 can be used in various use cases or applications. More specifically, Figure 6 and Figure 7 The example shown is a typical use case during normal operation, specifically when the device is controlled based on control data sent by the central control element 302. Figure 6 In the middle, the network is controlled in a bus mode, while... Figure 7 In this system, the network is controlled in serial mode.

[0130] Figure 7 The use of system 703 in bus mode is illustrated. System 703 includes a central control element 302 and devices 604 connected to each other via communication cables 701. Each device 604 includes an expansion element 600. For clarity, the read-write connection 605 and write-read connection 601 of the expansion element 600 are not shown in the figure. During normal operation in bus mode, each of the switches 405 is in the closed state. Therefore, a direct connection 700 is formed on each expansion element 600 between the first connection point 401 and the second connection point 402. Together with the communication cable 701, the direct connections 700 form a common bus for the network. Control data sent by the central control element 302 is simultaneously received by each of the devices 604. The system then operates in a manner similar to a conventional solution using the RS-485 standard and the DMX512 protocol, which is shown in Figure 2. A power failure in one of the devices 604 will not interrupt the data flow on the bus. Each extension element 600's processing unit 406 branches off from the bus 700-701 to receive all control data sent on the bus and can transmit the received control data to the corresponding control unit 203, which then operates the lamp 204.

[0131] Figure 7 The system 803 is shown in normal operation, but the network is controlled in serial mode instead of bus mode. Figure 7 It is shown that switch 405 is open on each expansion element 600. Therefore, no data flow is possible on the common bus. Instead, data flow now occurs through a direct connection 800 between the first interface 407 and the second interface 502 of each expansion element 600. For this purpose, a read-write connection 601 is used on the expansion element 600. If data flow occurs in the other direction, then a read-write connection 605 is used. In this case, a serial topology is thus employed, where consecutive interfaces transmit data to each other. This has the advantage over a bus topology that not all data flow will stop in the event of a cable short circuit. However, the disadvantage is that a power failure in device 604 will interrupt data flow. In the event of such a power failure, switch 405 must therefore be temporarily closed and operation must be carried out in bus mode.

[0132] Figure 8 and Figure 9 The expansion element 600 is shown in both forwarding and idle states. In both figures, switch 405 is open, indicating that the network is operating in serial mode. When control data is transmitted to device 604, such as... Figure 7As shown, the extension element 600 of successor device 604 is in a forwarding state. However, when no control data is exchanged, the extension element 600 will be placed in an idle state. For clarity, only the write-read connection 601 is shown in the figure. In reality, a read-write connection 605 also exists.

[0133] Figure 8 This illustrates that in forwarding state, control data is transmitted directly through write-read connection 601. When transmitted via direct connection 601, data is forwarded without any delay. Forwarding state is achieved by changing one or more impedances: the relative impedances of various connections change in a way that the electrical signal tends to flow along connection 601. Furthermore, during data transmission via extension elements, processing unit 406 actively follows the data frames being transmitted, such as... Figure 8 As shown in 804, various possibilities exist for changing the relative impedance of various connections. For example, the impedance in write-read connection 601 can be changed by means of a variable resistor placed in write-read connection 601 or by adjusting the impedance of one of the pins of the driver available in the first interface 407 or the second interface 502. In another example, the impedance in connection 408 or 501 between the interface and processing unit 406 is changed. For example, the pins of processing unit 406 can be set to low impedance or high impedance. Moreover, combined changes in impedance are also possible. In any case, the change of impedance(s) is triggered by processing unit 406, and the resulting relative impedance enables the desired data path to be achieved.

[0134] Figure 9 It is shown that in the idle state, no data flow is possible on write-read connection 601. Similarly, no data flow is possible on read-write connection 605, see 606. In this case, the relative impedance is changed in such a way that electrical signals tend to flow only along the path connected to processing unit 406. In this idle state, processing unit 406 can exchange messages with central control element 302, see 805 in the figure. For example, control element 302 can request the temperature of device 604, thereby using the RDM protocol.

[0135] Figure 10 This further illustrates when the extension element switches from an idle state to a forwarding state, and vice versa. Box 1300 indicates that the extension element 600 is in an idle state, i.e. Figure 9The states are represented in block 1303. When a transition is detected on the first driver 407, see block 1301, element 600 is placed in a forwarding state, where data is transferred from the first driver 407 to the second driver 502. Similarly, when a transition is detected on the second driver 502, see block 1302, element 600 is placed in a forwarding state, where data is transferred in the opposite direction from the second driver 502 to the second driver 501. The subsequent forwarding state in the opposite direction is represented in block 1304. Detecting a transition on the first driver 407 or the second driver 502 implies that data will be transmitted via the bus. In this way, processing unit 406 can detect the start of a data frame. When a data frame is transmitted via extension element 600, the processing unit actively tracks the passing data using a data tracker. This is represented in block 1307. Processing unit 406 is programmed to know the composition of a standard data frame according to the protocol used. In this way, processing unit 406 detects the end of a data packet, see blocks 1305 and 1306. Upon detecting the end of a data frame, extension element 600 is returned to an idle state, as indicated by block 1300.

[0136] Figure 11 Data frame 1400 is schematically represented and has components defined by the protocol used. In the illustrated embodiment, the DMX512 protocol is used to control device 604. Figure 11 Only the main portion of data frame 1400 is schematically shown. Data frame 1400 includes an interrupt period 1401, followed by an interrupt post-mark 1402. During the interrupt period 1401, no actual control data is transmitted. Furthermore, data frame 1400 includes data slots 1403 corresponding to the sequence of control data. In the DMX512 protocol, 512 slots are provided, corresponding to the 512 channels available in DMX. Finally, 1404 indicates the pre-interrupt mark. In DMX512, the minimum interruption (transmission) time is 176 microseconds, and the minimum interruption (reception) time is 88 microseconds.

[0137] When extension element 600 detects data frame 1400, processing unit 406 switches the element from idle state to forwarding state. This is done sequentially by each consecutive element 600 present in the network chain. Due to the interruption period 1401 in the data frame, the first element 600 will only begin reading the actual control data 1403 after the last element 600 in the chain has switched to forwarding state. In other words, the actual control data 1403 will be transmitted throughout the chain after all elements 600 have been placed in forwarding mode. Since each element 600 has a direct connection 601 between the two interfaces 407, 502 in forwarding mode, the control data 1403 will be transmitted throughout the chain without any substantial delay. Test results show that each extension element 600 receives a delay of approximately 0.5 microseconds, which is extremely small. Therefore, each device 604 receives its control data almost simultaneously, allowing for very accurate synchronous control. During the transmission of data frame 1400, processing unit 406 actively tracks data frame 1400. Furthermore, processing unit 406 is aware of the standard composition of data frame 1400, i.e., the rules according to the protocol used have been programmed into the logic of processing unit 406. Based on this, processing unit 406 can detect the end of data frame 1400. Specifically, processing unit 406 will detect that 512 data time slots in sequence 1402 have passed, thereby indicating that data frame 1400 has ended. Detecting the end of data frame 1400 will trigger processing unit 406 to return extension element 600 to the idle state.

[0138] Figure 12 An example is given on how to change between idle and forwarding states by altering the relative impedance. Figure 12 Only half is shown; clearly, the other half was obtained symmetrically. Figure 12 The diagram shows a processing unit 406 as a microcontroller 406, a first RS-485 driver 1501, and a second RS-485 driver 1502. Drivers 1501 and 1502 are included in a first interface 407 and a second interface 502 of an expansion element 600, respectively. Box 1509 represents a conventional 10k resistor, which is not adjustable. Driver 1501 includes pins or ports: enable pin 1503, Rx1 1504, and Tx1 1505. The second driver 1502 includes similar pins, with only pin Rx2 1507 shown. Microcontroller 406 includes an internal switch 1506 and a Tx1 pin 1510. The internal signal UART TX1 is represented by 1508.

[0139] Microcontroller 406 uses two control signals Z1 and E1 relative to the first driver 1501, and similarly uses two control signals Z2 and E2 relative to the second driver 1502. Control signal Z1 controls switch 1506. When Z1 is 1, switch 1506 is open, thus placing microcontroller pin TX1 1510 at high impedance. When Z1 is 0, switch 1506 is closed, thus placing microcontroller pin TX1 1510 at low impedance, connected to the internal signal UART TX1 1508. Control signal EN1 enables the first driver 1501. Additionally:

[0140] • Signal Rx1 1504 is always driven by RS-485 driver 1501.

[0141] • Signal EN1 1503 is always driven by microcontroller 406.

[0142] When switch 1506 is closed (Z1 = 0), signal Tx1 1505 at the first driver 1501 is driven by UART-Tx1 1508. When switch 1506 is open (Z1 = 1), signal Tx1 1505 at the first driver 1501 is driven by Rx2 1507 of the second driver 1502 via 10k resistor 1509.

[0143] When EN1 is 0, the value of Z1 is irrelevant because the value at pin 1505 of the first driver 1501 is not transmitted to the line. When EN1 is 1, the signal is placed at the first driver 1501 depending on the value of Z1: if Z1 = 0, the signal comes from UART_Tx1 1508; if Z1 = 1, the signal comes from Rx2 1507. Therefore, the following state changes can be achieved by controlling the control signals Z1, Z2, EN1, and EN2:

[0144] • Idle state: EN1 = 0, EN2 = 0 (Z1 and Z2 are unrelated)

[0145] Transmission 1: EN1=1, Z1=0, EN2=0

[0146] Forwarding status (forwarding from the second interface to the first interface): EN1=1, Z1=1, EN2=0

[0147] Transmission 2: EN1=0, EN2=1, Z2=0

[0148] Forwarding status (forwarding from interface 1 to interface 2): EN1=0, EN2=1, Z2=1

[0149] This illustrates that in order to change from an idle state to a forwarding state, Z1 or Z2 changes from 0 to 1, thus creating a high impedance at the microcontroller pin TX1 1510. In other words, the impedance in the branch running from the microcontroller 406 is increased, allowing data to flow via a direct connection between the two interfaces.

[0150] Figure 13 and Figure 14 This illustrates a use case for determining the order of devices in a network during initial configuration. To do this, a central control element identifies which devices are connected and their order of location within the network. Figure 13 The first method for determining the order in a sequential manner is shown, while Figure 14 A second method using neighbor determination is shown. In both cases, the network operates in bus mode, but during initial configuration, the selected switch 405 is temporarily turned on.

[0151] exist Figure 13 In this system 905, there are devices 604 and a central control element 902. Each device 604 includes an expansion element 600. For clarity, not every detail of the expansion element 600 is shown in the figure.

[0152] The central control element 902 includes a topology module 904 configured to determine the order of devices 604 in the network by executing a sequence. This sequence includes, for example, the following steps executed sequentially:

[0153] -The initial situation is that all switches 405 of the expansion element 600 are closed.

[0154] Central control element 902 sends a command to open switch 405 via common bus 700-701. This command is received by each processing unit 406. Then all switches 405 are opened. This process occurs in... Figure 13 As shown in the diagram. At this moment, only the first device "A" is still connected to the central control element 902 via the bus.

[0155] Next, the central control element 902 sends a request to successively return its identifier, close switch 405, and cease responding to subsequent requests. This request is received only by the first device "A" (see 906). Device "A" responds by returning its identifier (e.g., its ESTA code or another ID). Since only one device is connected to the bus at this time, multiple devices will never respond simultaneously. After sending its response, device "A" closes its switch 405, and processing unit 406 will cease responding to subsequent requests.

[0156] Then the central control element 902 sends the same request again. Given that switch 405 of device "A" is closed, this request is received by both "A" and "B". However, device "A" no longer responds, so only device "B" responds by returning its identifier.

[0157] - Repeat sending this request until no device 404 responds. At that moment, the central control element 902 has received the identifier of each device, and based on the order in which they appear, the topology module 904 determines the order of the devices 404 connected in the chain.

[0158] In this way, the order can be automatically determined by the topology module 904. The central control element 902 also includes a configuration module 903. After the topology module 904 identifies and determines the order, the configuration module 903 can, for example, send a message addressing a specified device 604, specifying the starting address. The entire configuration can be performed automatically in this manner.

[0159] Figure 14 The order in which devices 604 are connected, determined based on neighbor identification in a second manner, is shown. Figure 10 In this system 1005, devices 604 and a central control element 1002 having a topology module 1004 are included. Each device 604 includes an extension element 600 according to a second embodiment. Again, not every detail of the extension element 600 is shown in the figures. Furthermore, the processing unit 406 of each extension element 600 is configured to identify neighboring devices. The topology module 1004 is configured to determine the order of devices 604 in a second manner based on a neighbor determination by executing a sequence. For example, this sequence includes the following steps executed sequentially:

[0160] - In the first step, the central control element 1002 issues a command to open all switches 405 and requests which device is present to identify the first device. Given that at that moment only the first device "A" is connected to the bus, the topology module 1004 receives the ID of "A".

[0161] Then all switches 405 close again and the topology module sends a command to identify neighboring devices. This command is received by each expansion element 600.

[0162] Then the processing unit 406 of the extension element 600 in each device 604 executes the required sequence to identify neighboring devices. This situation occurs in... Figure 14 The process is as follows: First, processing unit 406 turns on switch 405. Next, processing unit 406 requests an ID from its adjacent device on the right via second interface 502. Figure 10In this diagram, device "B" receives the ID via its second interface 502 and transmits the ID itself via its first interface 407, as shown in 1001 and 1003 in the figure, respectively. Then, switch 405 is closed again. Each device 604 now knows the ID of its right neighbor, and all switches 405 are closed again.

[0163] Next, topology module 1004 sends a request via the bus to address the first device "A" previously identified in the first step. This request requests the transmission of the ID of its right neighbor. Once received, topology module 1004 identifies the second device "B".

[0164] Next, topology module 1004 sends a request to address the second device "B" to transmit the ID of its right neighbor. By repeating this process by topology module 1004, all devices 604 are identified and their order is determined. Furthermore, this method of determining the order is faster than the first sequential method.

[0165] The second method described above, which determines the order of connected devices 604 based on neighbor determination, can be similarly applied by manipulating the relative impedance instead of manipulating switch 405. In this case, switch 405 for each expansion element 600 remains open throughout the configuration phase. Neighbor determination is now performed by "opening" read-write and write-read connections, thus preventing transmission along these lines. With these lines open, each device 604 requests the ID of its right neighbor and transmits its own ID to its left neighbor. After all connections are "closed" again, but switch 405 remains open, topology module 1004 can then request all IDs. The "opening" and "closing" by changing the relative impedance allows for faster operation than neighbor determination via opening and closing switch 405. In this last method, a specific latency required for stabilization must be inserted after switch 405 is closed. This latency is unnecessary when the impedance is changed to the "closed" state.

[0166] exist Figure 15 The example shown illustrates a case where the communication cable experiences a short circuit during normal operation while operating in bus mode. Figure 15 In this system 1105, there is a device 604 and a central control element 1102 having a self-healing module 1004. Figure 15 In this diagram, each device 604 includes an extension element 600. For clarity, not every detail of the extension element 600 is shown.

[0167] The processing unit 406 of each expansion element 600 is configured to detect defects in the connected communication cable, such as a short circuit 1104. To this end, the processing unit 406 is configured to continuously monitor the first interface 407 and the second interface 502. For example, it continuously checks the voltage difference between the signal lines. In the case of differential signaling, this voltage difference should be zero; a deviation from zero indicates an anomaly. If the processing unit 406 detects an anomaly, it activates switch 405 and sends an error message to the central control element 1102.

[0168] The central control element 1102 includes a self-healing module 1100, which enables the restoration of data flow in the event of a fault in the communication cable. For example, this is done as follows:

[0169] A short circuit 1104 occurred in the communication cable between devices "A" and "B". All data flow on buses 700-701 then stopped.

[0170] Device "A" detects an anomaly on its second interface 502, see 1107. Then, expansion element 600 of device "A" activates its switch 405. The bus is thus interrupted at this location, enabling data flow on the bus to the left of device "A". Device "A" sends an error message to the self-healing module 1100 via this route.

[0171] - Device "B" also detected an anomaly on its first interface 407, see 1108. Device "B" also turned on its switch 405. The switches 405 on both sides of defect 1104 are now open. This situation occurs in... Figure 15 The defective cable is isolated from the network by the open switch 405. Therefore, except for the defective cable 1104, the public bus can be reused, to the left of device "A" (see 1103) and to the right of device "B" (see 1106).

[0172] Upon receiving an error message, the self-healing module 1100 adjusts the data flow: it travels along the route indicated by 1103 to device "A," while traveling along the route indicated by 1101 to devices "B" and "C." For this to work, the network must be connected in a loop, such as... Figure 11 This is indicated in the text. In this way, data traffic is automatically restored.

[0173] at last, Figure 16An alternative method for monitoring the first interface 407 or the second interface 502 is shown, wherein anomaly detection is not based on a measured voltage difference, but rather uses the read and write ports of the interface. In this way, the cost of additional components for voltage measurement can be avoided. An expansion element 600 is shown in the figure. The first interface 407 includes a read port "R1" and a write port "W1". The second interface 502 includes a read port "R2" and a write port "W2". The processing unit 407 is configured to monitor the read and write ports. For example, this is done as follows:

[0174] - In normal operation, switch 405 is closed. The content sent by processing unit 406 reaches the write port "W2" of the second interface 502, see 1203. Provided there are no defects in the cable, it will also reach the read port "R1" of the first interface 407 via the closed switch 405. Processing unit 406 reads this read port "R1", see 1202, and compares it with the content it initially sent. As long as they are the same, no anomaly is detected.

[0175] However, if a short circuit 1200 occurs in the second communication cable 206, the content sent by the processing unit 406 will not reach the read port "R1". Therefore, the processing unit detects a difference between the content it initially sent and the content it is now reading. In this way, an anomaly 1200 is detected.

[0176] - The processing unit 406 can detect anomalies in the first communication cable 205 in a similar manner, see 1201 and 1204.

[0177] Although the invention has been described with reference to specific embodiments, it will be clear to those skilled in the art that the invention is not limited to the details of the illustrative embodiments described above, and various changes and modifications can be made to the invention without departing from the scope of application of the invention. Therefore, the embodiments described herein must be considered illustrative rather than restrictive in all fields, and the scope of application of the invention is described by the appended claims rather than the foregoing description, and any changes that fall within the meaning and scope of the claims are incorporated herein. In other words, it is assumed that this covers all changes, variations, etc., within the scope of application of the basic principles and essential attributes claimed in this patent application. Furthermore, the reader of this patent application will understand that the terms "comprising" or "comprise" do not exclude other elements or steps, the terms "a(n)" or "one" do not exclude a plurality, and a single element (such as a computer system, processor, or another integrated unit) can perform the functions of the various auxiliary components mentioned in the claims. Any references in the claims should not be construed as limiting the corresponding claims. The terms "first," "second," "third," "a," "b," "c," etc., used in the specification or claims are used to distinguish similar elements or steps and do not necessarily indicate an order or chronological sequence. Similarly, the terms "top side," "bottom side," "above," "below," etc., are used for descriptive purposes and do not necessarily refer to relative positions. It should be understood that these terms are interchangeable where appropriate, and embodiments of the invention may function in a different order or orientation than those described or illustrated above.

Claims

1. An expansion element (600) for a device (604), the device (604) being adapted to be connected to other devices in a linear network having a bus topology via a first communication cable (205) and a second communication cable (206), wherein the expansion element (600) comprises: a first connection point (401) and a second connection point (402) adapted to connect the expansion element (600) to the first communication cable (205) and to the second communication cable (206), respectively; a third connection point (403) adapted to connect the expansion element (600) to a control unit (203) comprised in the device (604); a switch (405) connected to the first connection point (401) and to the second connection point (402); a processing unit (406) connected to the third connection point (403) and to the first connection point (401) and to the second connection point (402) by connections not comprising the switch (405); a first interface (407) and a second interface (502) adapted to exchange data between the first connection point (401) and the second connection point (402) and the processing unit (406), respectively; a read-write connection (605) between a read port of the first interface (407) and a write port of the second interface (502) and a write-read connection (601) between a write port of the first interface (407) and a read port of the second interface (502), wherein the processing unit (406) is configured to: modify a state of the switch (405) such that: in a closed state of the switch (405), a direct connection exists between the first connection point (401) and the second connection point (402), the direct connection not comprising the first interface (407) and the second interface (502), and in an installed state, forms part of a common bus (700, 701) of the network; in an open state of the switch (405), the direct connection is interrupted; change an impedance in the read-write connection (605) or in the write-read connection (601) or in the connection between the first interface (407) and the second interface (502) via the processing unit (406) in order to change a state of the expansion element (600) from an idle state in which data traffic is not possible through the read-write connection (605) and the write-read connection (601) to a forwarding state in which data traffic is possible through the read-write connection (605) or the write-read connection (601).

2. The expansion element (600) according to claim 1, wherein the extension element (600) is adapted to be mounted in a housing (108) of the device (604), and wherein the first connection point (401) and the second connection point (402) are adapted to be connected, in the mounted state, with an input port (201) and an output port (202) comprised in the housing (108) of the device (604), respectively.

3. The extension element (600) according to claim 1, wherein the processing unit (406) is configured to: interpret control data and configuration settings received via the first connection point (401) and transmit the control data and the configuration settings to the control unit (203) via the third connection point (403); request one or more characteristics of the device via the third connection point (403) and transmit the characteristics via the first connection point (401).

4. The extension element (600) according to claim 1, wherein the extension element (600) is adapted to control the device (604) according to a protocol, wherein the protocol defines a composition of a data frame (1400) comprising a sequence (1403) of control data intended for successive devices in the network, and an interruption period (1401) preceding the sequence (1403) of control data.

5. The extension element (600) according to claim 4, wherein the interruption period (1401) of the data frame (1400) is such that the time for the extension elements (600) of successive devices (604) to successively enter a forwarding state is less than the interruption period (1401).

6. The extension element (600) according to claim 4, wherein the processing unit (406) is configured to change the state from an idle state to a forwarding state at the beginning of the data frame (1400) and to change the state from the forwarding state to the idle state at the end of the data frame (1400).

7. The extension element (600) according to claim 6, wherein the processing unit (406) comprises a data tracker configured to actively track the data frame (1400) as it is transmitted via the read-write connection (605) or the write-read connection (601) and to detect the end of the data frame (1400) based on the data frame composition defined by the protocol.

8. The extension element (600) according to claim 1, wherein the processing unit (406) is configured to identify a neighboring device by: successively opening the switch (405), sending a request to the neighboring device via the second connection point (402) and receiving a response comprising an identifier of the neighboring device, or successively entering an idle state of the switch (405), sending a request to the neighboring device via the second connection point (402) and receiving a response comprising an identifier of the neighboring device.

9. The extension element (600) according to any one of claims 1-8, wherein the processing unit (406) is configured to detect a defect (1104) in the second communication cable (206) or the first communication cable (205) by monitoring the second interface (502) and the first interface (407), respectively, and upon detecting an anomaly, opening the switch (405) and sending an error message via the first interface (407) and the second interface (502), respectively.

10. A device (604) adapted to be connected to other devices in a linear network having a bus topology via a first communication cable (205) and a second communication cable (206), the device (604) comprising: electrical (204) and / or mechanical components; a control unit (203) adapted to control the electrical (204) or mechanical components; the extension element (600) according to one of the preceding claims, wherein the third connection point (403) of the extension element (600) is connected to the control unit (203).

11. A system for controlling a network of devices, comprising: one or more devices (604) according to claim 10; a central control element (302); one or more communication cables (205, 206), wherein each communication cable connects two of the devices (604) to each other or one of the devices (604) to the central control element (302), wherein the central control element (302) is configured to transmit data to and receive data from the network.

12. The system according to claim 11, wherein each of the devices (604) comprises an extension element (600) according to claim 8, and wherein the central control element (1002) comprises a topology module (1004) configured to determine an order of the devices (604) in the network by successively performing the following operations: transmitting a command so that the extension element (600) of each of the devices (604) identifies a neighboring device; requesting from each of the devices (604) an identifier of the device and an identifier of the identified neighboring device.

13. The system according to claim 11 or 12, wherein each of the devices (604) comprises an extension element (600) according to claim 9, and the central control element (1102) and the devices (604) are connected in a ring, and wherein the central control element (1102) comprises a self-healing module (1100) configured to identify a communication cable having a defect (1104) upon receiving an error message from one of the devices (604) and to adjust data traffic accordingly.

14. A method for communicating in a network of devices (604) interconnected via a first communication cable (205) and a second communication cable (206), wherein the network has a linear bus topology, the method comprising: providing an extension element (600) for each of the devices (604), comprising a first connection point (401), a second connection point (402) and a third connection point (403), a switch (405) connected to the first connection point (401) and to the second connection point (402), a processing unit (406) connected to the third connection point (403) and to the first connection point (401) and to the second connection point (402) by connections not including the switch (405), a first interface (407) and a second interface (502) adapted for data exchange between the first connection point (401) and the second connection point (402) and the processing unit (406), respectively; a read-write connection (605) between a read port of the first interface (407) and a write port of the second interface (502), and a write-read connection (601) between a write port of the first interface (407) and a read port of the second interface (502), connecting the first connection point (401) and the second connection point (402) to the first communication cable (205) and to the second communication cable (206), respectively; connecting the third connection point (403) to a control unit (203) comprising each of the devices (604); closing the switch (405) by the processing unit (406) such that a direct connection exists between the first connection point (401) and the second connection point (402) forming part of a common bus (700, 701) of the network, thereby controlling the network in a bus mode; opening the switch (405) by the processing unit (406) such that the direct connection is interrupted, thereby controlling the network in a serial mode; in the serial mode, changing by the processing unit (406) the read-write connection (605) and / or the write-read connection (601) and / or an impedance in the connection between the first interface (407) and the second interface (502) via the processing unit (406) such that a state of the extension element (600) is changed from an idle state in which no data traffic is possible through the read-write connection (605) and the write-read connection (601) to a forwarding state in which data traffic is possible through the read-write connection (605) or the write-read connection (601).

15. The method according to claim 14, the method further comprising: providing an extension element (600) according to claim 6; controlling the network in the serial mode; upon detection of a start of a data frame (1400) by the extension element (600) of a successive device (604): entering the extension element (600) into a forwarding state; transmitting said data frame (1400) via said read-write connection (605) or said write-read connection (601) of the successive device (604); upon detection of the end of a data frame (1400) by the expansion element (600) of the successive device (604): causing the expansion element (600) to enter an idle state.

16. The method according to claim 15, wherein said interruption period (1401) of said data frame (1400) is such that the time for causing the expansion element (600) of the successive device (604) to successively enter a forwarding state is less than said interruption period (1401).

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