Data transmission control

Abstract

A device 208 for controlling data transmission from a damper control device 202 to a wired communication network 206 to which is connected one or more dampers 218, the device comprising: a control uni

Description

FIELD OF THE INVENTION The present invention relates to data transmission control, and in particular, a device for controlling data transmission from a damper control device to a wired communication network to which is connected one or more dampers BACKGROUND A damper can be used in a duct system to control the flow of air. Dampers can open and close accordingly to vary the volume of flow of air through the damper. The duct system can be connected to supply or extract an air flow. One particular use of a damper is a smoke control damper. In the event of a fire, the damper can be opened to direct a flow of air to extract smoke carried by the air through the damper, therefore extracting an air flow. In a building or enclosure, this can direct smoke out of rooms or areas or away from other buildings. A further use of a damper when installed in a room or area is for air ventilation. Air is supplied to a room through the damper to ensure adequate ventilation (in some cases the damper extracts air from a source at another position in the room to provide ventilation). In a known damper system, one or more dampers may be coupled to a wired communication network such as a RS-485 Modbus communication network. A damper control device is typically provided to be in communication with the wired communication network to enable the damper control device to receive data from the dampers (e.g. damper blade position information, and status information), and to transmit data to the dampers (e.g. commands to control blades of the dampers to be positioned at different degrees of opening angles). SUMMARY In the known damper system, if there is a cable breakage in the wired communication network all the network devices (e.g. dampers) from that point to one end of a communication line are isolated from the communication bus. The inventors have identified the need to ensure that a damper control device can still communicate with dampers coupled to a wired communication network in the event of a breakage in the network or any other communication line interruptions. According to one aspect of the present disclosure there is provided a device for controlling data transmission from a damper control device to a wired communication network to which is connected one or more dampers, the device comprising: a control unit; at least one switching device, the at least one switching device coupled to (i) a first end of a communication bus of the wired communication network, and (ii) a second end of the communication bus, the second end opposing the first end; wherein the control unit is configured to: control the at least one switching device for transmission of a data message, via the at least one switching device, to the first end of the communication bus; detect a network breakage in the wired communication network; and in response to the detection, control the at least one switching device for retransmission of the data message, via the at least one switching device, to the second end of the communication bus. The at least one switching device may comprise: a first switching device coupled to the first end of the communication bus of the wired communication network; and a second switching device coupled to the second end of the communication bus; wherein the control unit is configured to: control the first switching device and the second switching device for transmission of the data message, via the first switching device, to the first end of the communication bus; and in response to the detection, control the first switching device and the second switching device for re-transmission of the data message, via the second switching device, to the second end of the communication bus. At least one of the first switching device and the second switching device may be a solid state relay. The at least one switching device may comprise a single switching device, optionally the single switching device is a solid state relay. In some embodiments, the control unit is configured to detect the network breakage in the wired communication network based on receipt of a command from the damper control device. The wired communication network may be configured to communicate data in accordance with a communication protocol, and the device further comprises a communications interface configured to receive the data message in accordance with the communication protocol. The communication protocol may be the RS-485 communication protocol. The control unit may be coupled to the at least one switching device, and may be configured to: transmit a control signal to the at least one switching device to control the at least one switching device for said transmission of the data message; transmit a further control signal to the at least one switching device to control the at least one switching device for said re-transmission of the data message. The wired communication network may be configured to communicate data in accordance with a first communication protocol, and the control unit may be configured to receive the command and the data message in accordance with a second communication protocol, the second communication protocol different to the first communication protocol. The device may further comprise a switching device controller coupled to the at least one switching device, wherein the control unit may be configured to transmit the command to the switching device controller in accordance with the second communication protocol, and the switching device controller may be configured to: transmit a control signal to the at least one switching device to control the at least one switching device for said transmission of the data message; and in response to receipt of the command, transmit a further control signal to the at least one switching device to control the at least one switching device for said re-transmission of the data message. The control unit may be coupled to the at least one switching device, and may be configured to transmit the data message to the at least one switching device in accordance with the first communication protocol. The first communication protocol may be the RS-485 communication protocol. The second communication protocol may be one of: Universal Serial Bus (USB) communication protocol; Universal Asynchronous Receiver / Transmitter (UART) communication protocol; or RS-232 communication protocol. In some embodiments, the control unit is configured to: transmit the data message via the at least one switching device to the first end of the communication bus; store the data message in a memory of the device; detect the network breakage in the wired communication network; in response to detecting the network breakage in the wired communication network, retrieve the data message from memory and retransmit the data message via the at least one switching device to the second end of the communication bus. The control unit may be configured to: detect that a response to the data message has not been received from a damper coupled to the communication bus, within a predefined interval of the transmission of the data message; retrieve the data message from memory; retransmit the data message, via the at least one switching device to the first end of the communication bus, a predetermined number of times; and detect the network breakage in the wired communication network if no response is received from the damper after the retransmission of the data message the predetermined number of times. The device may further comprise a switching device controller coupled to the at least one switching device, wherein in response to detecting the network breakage in the wired communication network, the control unit may be configured to transmit a command to the switching device controller, the switching device controller may be configured to: transmit a control signal to the at least one switching device to control the at least one switching device for said transmission of the data message; and in response to receipt of the command, transmit a further control signal to the at least one switching device to control the at least one switching device for said re-transmission of the data message. The wired communication network may be configured to communicate data in accordance with a first communication protocol, and the control unit may be coupled to the at least one switching device, and configured to transmit the data message to the at least one switching device in accordance with the first communication protocol. The control unit may be configured to receive the data message in accordance with a second communication protocol, the second communication protocol different to the first communication protocol. The second communication protocol may be one of: Universal Serial Bus (USB) communication protocol; Universal Asynchronous Receiver / Transmitter (UART) communication protocol; or RS-485 communication protocol The first communication protocol may be RS-485 communication protocol. According to another aspect of the present disclosure there is provided a method of controlling data transmission from a damper control device to a wired communication network to which is connected one or more dampers, the method comprising: controlling at least one switching device for transmission of a data message, via the at least one switching device, to a first end of a communication bus of the wired communication network, wherein the at least one switching device is coupled to (i) the first end of the communication bus of the wired communication network, and (ii) a second end of the communication bus, the second end opposing the first end; detecting a network breakage in the wired communication network; and in response to the detection, controlling the at least one switching device for retransmission of the data message, via the at least one switching device, to the second end of the communication bus. According to another aspect of the present disclosure there is provided a non-transitory computer-readable storage medium comprising instructions which, when executed by at least one processor cause the at least one processor to perform any of the methods described herein. The instructions may be provided on one or more carriers. For example there may be one or more non-transient memories, e.g. a EEPROM (e.g. a flash memory) a disk, CD- or DVD-ROM, programmed memory such as read-only memory (e.g. for Firmware), one or more transient memories (e.g. RAM), and / or a data carrier(s) such as an optical or electrical signal carrier. The memory / memories may be integrated into a corresponding processing chip and / or separate to the chip. Code (and / or data) to implement embodiments of the present disclosure may comprise source, object or executable code in a conventional programming language (interpreted or compiled) such as C, or assembly code, code for setting up or controlling an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or code for a hardware description language. According to another aspect of the present disclosure there is provided a system comprising: a damper control device; a wired communication network to which is connected one or more dampers; and a device according to any of the embodiments described herein. These and other aspects will be apparent from the embodiments described in the following. The scope of the present disclosure is not intended to be limited by this summary nor to implementations that necessarily solve any or all of the disadvantages noted. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present disclosure and to show how embodiments may be put into effect, reference is made to the accompanying drawings in which: Figure 1 illustrates a prior art system; Figures 2a and 2b illustrate a device in accordance with an embodiment of the present disclosure; Figure 3 illustrates a process for controlling data transmission from a damper control device to a wired communication network; Figure 4a and 4b illustrate a device in accordance with an embodiment of the present disclosure; Figure 5a and 5b illustrate a device in accordance with an embodiment of the present disclosure; Figure 6 illustrates a damper in a closed position; Figure 7 illustrates a damper in an open position; and Figure 8 illustrates a breakage in a wired communication network. DETAILED DESCRIPTION Figure 1 illustrates a known system 100 which comprises a damper control device 102, a communication converter 104, and a wired communication network 106. The wired communication network 106 comprises one or more connection points 108 at which a damper may be connected. The wired communication network 106 is configured to communicate data in accordance with a first communication protocol, such as the RS-485 communication protocol. For example, the wired communication network 106 may be a Modbus RS-485 network. The communication converter 104 is configured to receive data from the damper control device 102 in accordance with a second communication protocol which is different to the first communication protocol, and output the data to the wired communication network 106 in accordance with the first communication protocol. Similarly, the communication converter 104 is configured to receive data from the wired communication network 106 in accordance with the first communication protocol, and output the data to the damper control device 102 in accordance with the second communication protocol. The communication converter 104 may be a standalone device as shown in Figure 1, or it may be integrated into the damper control device 102. As illustrated in Figure 1, in the known damper system 100, if there is a network breakage (shown by the ‘X’) all the dampers connected to a connection point 108 that is located after the network breakage are isolated from being able to communicate with the damper control device 102. Embodiments of the present disclosure will now be described by way of example only. Embodiments of the present disclosure relate to a device for controlling data transmission from a damper control device to a wired communication network to which is connected one or more dampers. If the device detects a breakage in the wired communication network after transmission of a message from the damper control device to a first entry point at one end of the wired communication network, the device changes a communication direction flow towards the wired communication network to enable retransmission of the data message to a second entry point at an opposite end of the wired communication network to ensure that the message is received by all intended recipient damper devices. Reference is first made to Figure 2a which illustrates a system 200. The system 200 comprises a damper control device 202, a communication converter 204, a wired communication network 206, and a device 208 for controlling data transmission from the damper control device 202 to the wired communication network 206. The damper control device 202 is a computing device configured to transmit data in the form of damper communication messages to the dampers (e.g. comprising commands to control blades of the dampers to be positioned at different degrees of opening angles) connected to the wired communication network 206. The damper control device 202 is further configured to receive data output from the dampers (e.g. damper blade position information, status information etc.). In the embodiments of Figures 2a and 2b, the damper control device 202 is configured to detect a breakage in the wired communication network 206, and in response, transmit a switching device control command to the device 208. The damper control device 202 is configured to transmit a damper communication message to a damper connected to the wired communication network 206. If, within a pre-defined interval after sending the damper communication message, the damper control device 202 does not receive a response from the damper, it will retry sending the damper communication message a predetermined number of times (e.g. one or more time). If the damper control device 202 does not receive a response after retransmitting the damper communication message the predetermined number of times, the damper control device 202 is configured to determine that there is a breakage in the wired communication network 206 (declares the damper as unreachable). It will be appreciated that if a retransmission of the damper communication message is successful (i.e. the damper control device 202 receives a response from the damper), then further retransmissions of the damper communication message are not necessary. The wired communication network 206 is configured to communicate data in accordance with a first communication protocol such as the RS-485 communication protocol or the KNX TP1 communication protocol. For example, the wired communication network 206 may be a Modbus RS-485 network. The communication converter 204 is configured to receive data (e.g. damper communication messages) from the damper control device 202 in accordance with a second communication protocol which is different to the first communication protocol, and output the data to the wired communication network 206 in accordance with the first communication protocol. Similarly, the communication converter 204 is configured to receive data from the wired communication network 206 in accordance with the first communication protocol, and output the data to the damper control device 202 in accordance with the second communication protocol. Thus the communication converter 204 handles the conversion between the first communication protocol and the second communication protocol (in both directions). The communication converter 204 may be a standalone device as shown in Figure 2a, or it may be integrated into the damper control device 202. The second communication protocol may for example be the Universal Serial Bus (USB) communication protocol, the Universal Asynchronous Receiver / Transmitter (UART) communication protocol; or RS-232 communication protocol. As shown in Figure 2a, the wired communication network 206 comprises a communications bus 216 to which is connected one or more connection points 218. Although not shown in the Figures, a damper may be connected to a connection point 218. In particular, one or more dampers may be connected to the communications bus 216 of the wired communication network 206. The wired communication network 206 comprises an interface at a first end (A) of the communication bus 216, and an interface at second end (B) of the communication bus 216. The first end (A) and second end (B) are at opposite ends of the communication bus 216. The device 208 comprises a communications interface 210, a control unit 212, and at least one switching device 214. The communications interface 210 is arranged to receive data (e.g. damper communication messages) in accordance with the first communication protocol from the communication converter 204, and output the data in the first communication protocol to the at least one switching device 214. The communications interface 210 is arranged to receive data in accordance with the first communication protocol from the at least one switching device 214, and output the data in the first communication protocol to the communication converter 204 for conversion before transmittal to the damper control device 202. The at least one switching device 214 is connected to the communications interface 210. The at least one switching device 214 is connected to the first end (A) of the communication bus 216 of the wired communication network 206 and the second end (B) of the communication bus 216 of the wired communication network 206. In the arrangement of the Figure 2a, the at least one switching device 214 comprises a first switching device 214a coupled to the first end (A) of the communication bus 216 of the wired communication network 206, and further coupled to the communications interface 210. The at least one switching device 214 further comprises a second switching device 214b coupled to the second end (B) of the communication bus 216 of the wired communication network 206, and further coupled to the communications interface 210. The switching device 214a may for example be a single pole double throw (SPDT) relay. Similarly, the switching device 214b may for example be a single pole double throw (SPDT) relay. One or both of the switching device 214a and switching device 214b may be an electromechanical relay. One or both of the switching device 214a and switching device 214b may be a solid state relay, to provide a higher safety integrity level (SIL) device. The control unit 212 is arranged to receive a switching device control command (otherwise referred to herein as a “command”) transmitted from the damper control device 202. The control unit 212 is coupled to the at least one switching device 214. In particular, in the arrangement of Figure 2a the control unit 212 is coupled to the first switching device 214a and the second switching device 214b, and is configured to control the first switching device 214a and the second switching device 214b in response to the switching device control command received from the damper control device 202. In a variant of the arrangement of the Figure 2a, as shown in Figure 2b the at least one switching device 214 may be only a single switching device 214. The provision of a single switching device 214 advantageously reduces the size of the device 208. For example, the single switching device 214 may be a double pole double throw (DPDT) relay. The single switching device 214 may be an electromechanical relay. The single switching device 214 may be a solid state relay to provide a higher safety integrity level (SIL) device. In the arrangement of Figure 2b the control unit 212 is coupled to the single switching device 214, and is configured to control the single switching device 214 in response to the switching device control command received from the damper control device 202. The operation of the control unit 212 is described in more detail below with reference to Figure 3. Figure 3 illustrates a process 300 for controlling data transmission from the damper control device 202 to the wired communication network 206 which may be performed by the control unit of any of the embodiments described herein. At step S302, the control unit controls the at least one switching device 214 for transmission of a damper communication message (otherwise referred to herein as a “data message”), via the at least one switching device 214, to the first end (A) of the communication bus. In particular, the control unit controls the at least one switching device 214 such that any damper communication message destined for the wired communication network 206 is output by the device 208, 408, 508 to the first end (A) of the communication bus 216 and not the second end (B) of the communication bus 216. At step S304, the control unit detects a breakage in the wired communication network 206. In response to detecting the breakage in the wired communication network 206, at step S306 the control unit controls the at least one switching device 214 for re-transmission of the damper communication message, to the second end (B) of the communication bus. In particular, the control unit 212 controls the at least one switching device 214 such that any damper communication message destined for the wired communication network 206 is output by the device 208, 408, 508 to the second end (B) of the communication bus 216 and not the first end (A) of the communication bus 216. In the embodiments of Figures 2a and 2b, step S302 is performed in response to the control unit 212 receiving a switching device control command from the damper control device 202. In the embodiments of Figures 2a and 2b, at step S302 the control unit 212 controls the at least one switching device 214 such that any damper communication message received at the communications interface 210 from the damper control device 202 is output by the device 208 to the first end (A) of the communication bus 216 and not the second end (B) of the communication bus 216. In the embodiments of Figures 2a and 2b, once step S302 has been performed, the damper control device 202 attempts transmission of a damper communication message to the one or more dampers connected to the wired communication network 206 via the device 208. In the embodiments of Figures 2a and 2b, the damper control device 202 is configured to detect a breakage in the wired communication network 206, and in response, transmit a switching device control command to the device 208. Thus, the control unit 212 detects a breakage in the wired communication network 206 at step S304 based on receiving a switching device control command from the damper control device 202. In the embodiments of Figures 2a and 2b, in response to detecting the breakage in the wired communication network 206, the control unit 212 controls the at least one switching device 214 for re-transmission of the damper communication message, to the second end (B) of the communication bus 216. In particular, the control unit 212 controls the at least one switching device 214 such that any damper communication message received at the communications interface 210 from the damper control device 202 is output by the device 208 to the second end (B) of the communication bus 216 and not the first end (A) of the communication bus 216. In the embodiments of Figures 2a and 2b, once step S306 has been performed, the damper control device 202 attempts re-transmission of a damper communication message to the one or more dampers connected to the wired communication network 206 via the device 208, and the device 208 outputs the re-transmitted damper communication message (received from the damper control device 202) to the second end (B) of the communication bus 216. Reference is now made to Figure 4a which illustrates a system 400. The system 400 comprises the damper control device 202, the wired communication network 206, and a device 408 for controlling data transmission from the damper control device 202 to the wired communication network 206. In the embodiments of Figures 4a and 4b, the damper control device 202 is configured to detect a breakage in the wired communication network 206, and in response, transmit a switching device control command to the device 408. The device 408 comprises a control unit 402, a switching device controller 404 and the least one switching device 214. As noted above, the wired communication network 206 is configured to communicate data in accordance with a first communication protocol such as the RS-485 communication protocol or the KNXTP1 communication protocol. The control unit 402 is configured to receive data (e.g. damper communication messages) from the damper control device 202 in accordance with the second communication protocol which is different to the first communication protocol. For example, the control unit 402 is configured to receive damper communication messages for transmission to the wired communication network 206, and any switching device control commands output by the damper control device 202, in accordance with the second communication protocol referred to herein. The control unit 402 is coupled to the switching device controller 404 and the at least one switching device 214. The control unit 402 is configured to transmit a switching device control command it receives from the damper control device 202 to the switching device controller 404 in accordance with the second communication protocol. For example the control unit 402 may receive a Request To Send (RTS) or Data Terminal Ready (DTR) command from the damper control device 202, and supply the RTS or DTR command to the switching device controller 404. The control unit 402 is configured to receive damper communication messages from the damper control device 202 in accordance with the second communication protocol which is different to the first communication protocol, and output the damper communication messages to the at least one switching device 214 in accordance with the first communication protocol. Similarly, the control unit 402 is configured to receive data from the wired communication network 206 in accordance with the first communication protocol, and output the data to the damper control device 202 in accordance with the second communication protocol. Thus the control unit 402 handles the conversion between the first communication protocol and the second communication protocol (in both directions) for data messages transmitted between the damper control device 202 and the wired communication network 206. The switching device controller 404 is coupled to the control unit 402 and the at least one switching device 214. The switching device controller 404 is configured to operate in the same manner as the control unit 212 described above in that the switching device controller 404 is operable to control the at least one switching device 214 in response to receipt of a switching device control command. In contrast to the embodiments of Figures 2a and 2b, the switching device controller 404 receives the switching device control command from the control unit 402, not directly from the damper control device 202. In the arrangement of Figure 4a the switching device controller 404 is coupled to the first switching device 214a and the second switching device 214b, and is configured to control the first switching device 214a and the second switching device 214b in response to the switching device control command received from the control unit 402. In a variant of the arrangement of the Figure 4a, as shown in Figure 4b the at least one switching device 214 may be only a single switching device 214. The provision of a single switching device 214 advantageously reduces the size of the device 408. In the arrangement of Figure 4b the switching device controller 404 is coupled to the single switching device 214, and is configured to control the single switching device 214 in response to the switching device control command received from the control unit 402. The control unit 402 is configured to perform the process 300 described above. The functionality of the control unit 402 described herein may be implemented in code (software) stored on a memory comprising one or more storage media, and arranged for execution on a processor comprising one or more processing units. The storage media may be integrated into and / or separate from the control unit 402. The code is configured so as when fetched from the memory and executed on the processor to perform operations in line with embodiments discussed herein. Alternatively, it is not excluded that some or all of the functionality of the control unit 402 is implemented in dedicated hardware circuitry (e.g. ASIC(s), simple circuits, gates, logic, and / or configurable hardware circuitry like an FPGA). In the embodiments of Figures 4a and 4b, step S302 is performed in response to the control unit 402 receiving a switching device control command from the damper control device 202. In the embodiments of Figures 4a and 4b, at step S302 the control unit 402 sends the switching device control command to the switching device controller 404 to control the at least one switching device 214 such that any damper communication message received at the control unit 402 from the damper control device 202 is output by the device 408 to the first end (A) of the communication bus 216 and not the second end (B) of the communication bus 216. In the embodiments of Figures 4a and 4b, once step S302 has been performed, the damper control device 202 attempts transmission of a damper communication message to the one or more dampers connected to the wired communication network 206 via the device 408. In the embodiments of Figures 4a and 4b, the damper control device 202 is configured to detect a breakage in the wired communication network 206, and in response, transmit a switching device control command to the device 408. Thus, the control unit 402 detects a breakage in the wired communication network 206 at step S304 based on receiving a switching device control command from the damper control device 202. In the embodiments of Figures 4a and 4b, in response to detecting the breakage in the wired communication network 206, the control unit 402 sends the switching device control command to the switching device controller 404 to control the at least one switching device 214 for re-transmission of the damper communication message, to the second end (B) of the communication bus. In particular, the switching device controller 404 controls the at least one switching device 214 such that any damper communication message received at the control unit 402 from the damper control device 202 is output by the device 408 to the second end (B) of the communication bus 216 and not the first end (A) of the communication bus 216. In the embodiments of Figures 4a and 4b, once step S306 has been performed, the damper control device 202 attempts re-transmission of a damper communication message to the one or more dampers connected to the wired communication network 206 via the device 408, and the device 408 outputs the re-transmitted damper communication message (received from the damper control device 202) to the second end (B) of the communication bus 216. The device 408 has just a single port for communication with the damper control device 202, which advantageously reduces the size of the device compared to the device 208 described above. The device 408 advantageously uses a single communication channel for the transfer of damper communication messages (destined for dampers on the wired communication network 206) and switching device control commands between the damper control device 202 and the device 408. In contrast, the device 208 uses two separate channels between the damper control device 202 and the device 208 - one for the transfer of damper communication messages (destined for dampers on the wired communication network 206), and another for switching device control commands. Reference is now made to Figure 5a which illustrates a system 500. The system 500 comprises the damper control device 202, the wired communication network 206, and a device 508 for controlling data transmission from the damper control device 202 to the wired communication network 206. The device 508 comprises a control unit 502, a memory 504, the switching device controller 404, and the least one switching device 214 as described above. In contrast to the previously described embodiments, in the embodiments of Figures 5a and 5b, the control unit 502 does not detect a breakage in the wired communication network 206 based on receiving a switching device control command from the damper control device 202. Instead, the control unit 502 detects a breakage in the wired communication network 206 itself. In particular, the control unit 502 is configured to transmit a damper communication message to a damper connected to the wired communication network 206. If, within a pre-defined interval after sending the damper communication message, the control unit 502 does not receive a response from the damper, it will retry sending the damper communication message a predetermined number of times (e.g. one or more time). If the control unit 502 does not receive a response after retransmitting the damper communication message the predetermined number of times, the control unit 502 is configured to determine that there is a breakage in the wired communication network 206 (declares the damper as unreachable). That is, in the embodiments of Figures 5a and 5b, the control unit 502 controls the direction of communication traffic flow, rather than the damper control device 202. It will be appreciated that if a retransmission of the damper communication message is successful (i.e. the control unit 502 receives a response from the damper), then further retransmissions of the damper communication message are not necessary. As noted above, the wired communication network 206 is configured to communicate data in accordance with a first communication protocol such as the RS-485 communication protocol or the KNXTP1 communication protocol. The control unit 502 is configured to receive data from the damper control device 202 in accordance with the second communication protocol which is different to the first communication protocol. For example, the control unit 502 is configured to receive damper communication messages for transmission to the wired communication network 206 in accordance with the second communication protocol referred to herein. The control unit 502 is coupled to a memory 504, the switching device controller 404 and the at least one switching device 214. The control unit 502 is configured to generate and transmit a switching device control command to the switching device controller 404 in accordance with the second communication protocol. The control unit 502 is configured to receive damper communication messages from the damper control device 202 in accordance with the second communication protocol which is different to the first communication protocol, and output the damper communication messages to the at least one switching device 214 in accordance with the first communication protocol. Similarly, the control unit 502 is configured to receive data from the wired communication network 206 in accordance with the first communication protocol, and output the data to the damper control device 202 in accordance with the second communication protocol. Thus, the control unit 502 handles the conversion between the first communication protocol and the second communication protocol (in both directions) for data messages transmitted between the damper control device 202 and the wired communication network 206. The control unit 502 is configured to perform the process 300 described above. The functionality of the control unit 502 described herein may be implemented in code (software) stored on a memory comprising one or more storage media, and arranged for execution on a processor comprising one or more processing units. The storage media may be integrated into and / or separate from the control unit 402. The code is configured so as when fetched from the memory and executed on the processor to perform operations in line with embodiments discussed herein. Alternatively, it is not excluded that some or all of the functionality of the control unit 502 is implemented in dedicated hardware circuitry (e.g. ASIC(s), simple circuits, gates, logic, and / or configurable hardware circuitry like an FPGA). In the embodiments of Figures 5a and 5b, at step S302 the control unit 502 generates and sends a switching device control command to the switching device controller 404 to control the at least one switching device 214 such that any damper communication message received at the control unit 502 from the damper control device 202 is output by the device 508 to the first end (A) of the communication bus 216 and not the second end (B) of the communication bus 216. In the embodiments of Figures 5a and 5b, once step S302 has been performed, the control unit 502 attempts transmission of a damper communication message (received from the damper control device 202) to the one or more dampers connected to the wired communication network 206 via the device 408. The control unit 502 is configured to store the damper communication message in the memory 504. In the embodiments of Figures 5a and 5b, the control unit 502 detects a breakage in the wired communication network 206 at step S304 itself (not based on receiving a switching device control command from the damper control device 202). In particular, at step S304, if within a pre-defined interval after sending the damper communication message the control unit 502 does not receive a response from the damper, the control unit 502 retrieves the damper communication message from the memory 504 and retransmits the damper communication message a predetermined number of times (e.g. one or more time) via the at least one switching device 214 to the first end (A) of the communication bus. If the control unit 502 does not receive a response after retransmitting the damper communication message the predetermined number of times, the control unit 502 is configured to determine that there is a breakage in the wired communication network 206 (declares the damper as unreachable). In the embodiments of Figures 5a and 5b, in response to detecting the breakage in the wired communication network 206, the control unit 502 generates and sends a switching device control command to the switching device controller 404 to control the at least one switching device 214 for re-transmission of the damper communication message, to the second end (B) of the communication bus. In particular, the switching device controller 404 controls the at least one switching device 214 such that any damper communication message output by the control unit 502 is transmitted by the device 508 to the second end (B) of the communication bus 216 and not the first end (A) of the communication bus 216. In the embodiments of Figures 5a and 5b, once step S306 has been performed, the control unit 502 retrieves the damper communication message from the memory 504 and attempts re-transmission of the damper communication message to the one or more dampers connected to the wired communication network 206, and the device 508 outputs the re-transmitted damper communication message to the second end (B) of the communication bus 216. The embodiments of Figures 5a and 5b advantageously provides for reduced complexity of the damper control device 202 (as the damper control device 202 does not perform detection of breakages in the wired communication network 206) and avoids the retransmission of the damper communication message between the damper control device 202 and the control unit 502. Furthermore, embodiments of Figures 5a and 5b advantageously avoid the need for a switching device control command to be transmitted between the damper control device 202 and the control unit 502 to control the at least one switch 214. It can be seen that in the embodiments of Figures 5a and 5b, the device 508 takes over some of the functions of the damper control device 202 such that the damper control device 202 only sends the damper communication messages destined for the wired communication network 206, whilst network breakage detection and recovery tasks are performed by the device 508. Referring to Figure 6, there is illustrated a damper 10 which may be connected to the wired communication network 206 at a connection point 218. As discussed below, the damper 10 is shown in the closed position 10A. The damper 10 is placeable in a duct or surface such as a wall and controls airflow through the damper 10. The damper 10 has a damper housing 12 that forms a channel or passage 16 through which airflow can pass through the damper housing 12 and thus damper 10. The damper housing 12 generally forms the sides or walls of the passage 16 such that there is an inlet and outlet from the passage 16. As shown in Figure 6, a four sided damper housing 12 is formed therefore providing a square or rectangular shape when viewed from the front. In the four sided damper 10 shown, the damper housing 12 has opposing sides formed between a top side 20 and a bottom side 18. Likewise, there are further opposing sides between a left side 26 and a right side 28 of the damper housing 12. Therefore, the periphery of the passage 16 is formed by the two sets of opposing sides. Airflow passes within these two sets of opposing sides through the passage 16 of the damper housing 12. Whilst a four sided damper has been described, numerous shapes for the damper 10 can be used depending on the requirements. For instance, a circular damper housing 12 can be used in some situations. Within the damper housing 12 are damper blades 14. The damper blades 14 are generally rectangular in shape when viewed from a plan view having a height and width and forming a damper blade surface. The damper blades 14 are arranged to extend across the width of the damper housing between the left side 26 and the right side 28 such that a single blade can extend between these opposing sides. Therefore, the longest side (e.g. width) of a rectangular blade 14 extends between the left side 26 and the right side 28. The damper blades 14 are also arranged within the damper housing 12 between the top side 20 and the bottom side 18. In this configuration, multiple blades are arranged in parallel between the top side 20 and bottom side 18. Whilst the terms, top 20, bottom 18, left 26 and right 28 sides have been used for the walls of the damper housing 12, it is to be understood that the walls can be orientated in any manner not limited by the terms “top”, “bottom”, “left” and “right”. The damper blades 14 can be orientated between a fully closed position 10A where airflow through the passage 16 is prevented to a fully open position 10B (Figure 7) where the airflow through the passage 16 is permitted to a maximum volume flow. Each damper blade 14 is pivotable on its own axis extending between the left 26 and right 28 sides of the damper housing 12. Therefore, each damper blade 14 can be moved to rotate about its axis, i.e. towards or away from the top 20 and bottom 18 sides of the damper housing 12. The passage 16 can be blocked to airflow when the damper blades 14 are rotated to an orientation that fills the passage 16 of the damper housing 12. Therefore, when the blade 14 is orientated substantially vertically, such that its surface is faced against the airflow through the passage 16, the damper 10 is closed, i.e. in the closed position 10A. Multiple blades 14 are positioned in the damper housing 12 and to close the damper 10 all of these are orientated substantially vertically such that airflow cannot pass through the passage 16. Therefore, when the blade is viewed from the front as a rectangle, the shortest side (e.g. height) of a rectangular blade 14 is positioned between the top side 20 and the bottom side 18. It will be appreciated that the complete prevention of airflow through the passage 16 may not occur in the closed position 10A due to sealing with surfaces, such as adjacent blades 14 and the sides of the damper housing 12. Referring to Figure 7, the damper 10 in the open configuration 10B is shown. The damper blades 14 can be moved between a closed 10A and an open position 10B. In the open position 10B the damper blades 14 are arranged to permit flow through the passage 16. The rotation of the blades 14 through their axis to a position wherein the blade 14 is orientated substantially horizontally, such that its surface is faced in-line with the airflow through the passage 16 to permit airflow over the blade 14 (and inbetween multiple blades 14), will result in the damper 10 being open, i.e. in an open position 10B. The open position 10B and closed position 10A describe a fully open and a fully closed configuration. Therefore, in the fully open position 10B, the blade 14 is orientated as flat and horizontal as is permissible to the flow of air through the passage 16. However, it will be appreciated that the blade 14 may not be completely horizontal in this configuration. There can be positions in which the damper blades 14 are held between fully open 10B and fully closed 10A where airflow is controlled between the two extremes. Whilst six damper blades 14 have been shown in Figures 6 and 7, any number of blades 14 can be provided. For instance, it is possible to have a single blade 14 to control the opening and closing of the passage 16. The damper blades 14 can be all the same size or they can have different sizes. However, a set of damper blades 14 being all the same size except for one blade 14 allows for a mostly uniform arrangement where the one differently sized blade is used as a sizing blade which allows a damper 10 to be accurately sized for a particular duct or damper space without changing the sizes of all the blades 14. The blades 14 in the closed position 10A do not need to be sized so that they fill the passage 16 such that the blade edges touch blade edges of adjacent blades 14. Instead, the blades 14 can overlap in the closed position 10A such that a front surface of a blade 14 overlaps with a back surface of an adjacent blade 14. This overlapping configuration provides a larger surface area for forming a seal with a blade 14. Therefore, in the closed position 10A, the blades 14 do not need to be fully vertical to be in a fully closed position 10A, instead the blades 14 are substantially vertical. In some cases, seals are provided at the edges of the blades 14. Referring to Figures 6 and 7, there is shown an actuator body 22 arranged on the side of the damper housing 12. In this case the actuator body 22 is arranged on the right side 28 of the damper body 12. The actuator body 22 forms part of the damper 10 and provides the actuation and control for moving the damper blades 14, such as between open and closed positions 10B, 10A. The actuator body 22 is arranged to receive and transmit damper communication messages from / to the damper control device 202 via the device 208, 408, 508. Figure 8 illustrates a breakage 802 (shown by the ‘X’) in a wired communication network 206. In known damper systems, if such a breakage occurred, a damper communication message transmitted to a first end (A) of the communication bus 216 would be able to reach a damper connected to connection point 218a, but all the remaining dampers connected to connection points 218b-g would be isolated from the communication bus 216 such that the damper communication message would be unable to reach these dampers. In embodiments of the present disclosure, if such a network breakage was detected by the device 208, 408, 508, the change of communication direction flow towards the wired communication network implemented by the device would enable retransmission of the damper communication message to the second end (B) of the communication bus 216 to ensure that the damper communication message can be received by all intended recipient damper devices. Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A device for controlling data transmission from a damper control device to a wired communication network to which is connected one or more dampers, the device comprising:a control unit;at least one switching device, the at least one switching device coupled to (i) a first end of a communication bus of the wired communication network, and (ii) a second end of the communication bus, the second end opposing the first end;wherein the control unit is configured to:control the at least one switching device for transmission of a data message, via the at least one switching device, to the first end of the communication bus;detect a network breakage in the wired communication network; andin response to the detection, control the at least one switching device for retransmission of the data message, via the at least one switching device, to the second end of the communication bus.

2. The device of claim 1, wherein the at least one switching device comprises:a first switching device coupled to the first end of the communication bus of the wired communication network; anda second switching device coupled to the second end of the communication bus;wherein the control unit is configured to:control the first switching device and the second switching device for transmission of the data message, via the first switching device, to the first end of the communication bus; andin response to the detection, control the first switching device and the second switching device for re-transmission of the data message, via the second switching device, to the second end of the communication bus.

3. The device of claim 2, wherein at least one of the first switching device and the second switching device is a solid state relay.

4. The device of claim 1, wherein the at least one switching device comprises a single switching device.

5. The device of claim 4, wherein the single switching device is a solid state relay.

6. The device according to any preceding claim, wherein the control unit isconfigured to detect the network breakage in the wired communication network based on receipt of a command from the damper control device.

7. The device according to claim 6, wherein the wired communication network is configured to communicate data in accordance with a communication protocol, and the device further comprises a communications interface configured to receive the data message in accordance with the communication protocol.

8. The device according to claim 7, wherein the communication protocol is RS-485 communication protocol.

9. The device according to any of claims 6 to 8, wherein the control unit is coupled to the at least one switching device, and is configured to:transmit a control signal to the at least one switching device to control the at least one switching device for said transmission of the data message;transmit a further control signal to the at least one switching device to control the at least one switching device for said re-transmission of the data message.

10. The device according to claim 6, wherein the wired communication network is configured to communicate data in accordance with a first communication protocol, and the control unit is configured to receive the command and the data message in accordance with a second communication protocol, the second communication protocol different to the first communication protocol.

11. The device according to claim 10, further comprising a switching device controller coupled to the at least one switching device,wherein the control unit is configured to transmit the command to the switching device controller in accordance with the second communication protocol, andthe switching device controller is configured to:transmit a control signal to the at least one switching device to control the at least one switching device for said transmission of the data message; andin response to receipt of the command, transmit a further control signal to the at least one switching device to control the at least one switching device for said retransmission of the data message.

12. The device according to claim 10 or 11, wherein the control unit is coupled to the at least one switching device, and is configured to transmit the data message to the at least one switching device in accordance with the first communication protocol.

13. The device according to any of claims 10 to 12, wherein the first communication protocol is RS-485 communication protocol.

14. The device according to any of claims 10 to 13, wherein the second communication protocol is one of:Universal Serial Bus (USB) communication protocol;Universal Asynchronous Receiver / Transmitter (UART) communication protocol; orRS-232 communication protocol.

15. The device according to any of claims 1 to 5, wherein the control unit is configured to:transmit the data message via the at least one switching device to the first end of the communication bus;store the data message in a memory of the device;detect the network breakage in the wired communication network;in response to detecting the network breakage in the wired communication network, retrieve the data message from memory and retransmit the data message via the at least one switching device to the second end of the communication bus.

16. The device according to claim 15, wherein the control unit is configured to:detect that a response to the data message has not been received from a damper coupled to the communication bus, within a pre-defined interval of the transmission of the data message;retrieve the data message from memory;retransmit the data message, via the at least one switching device to the first end of the communication bus, a predetermined number of times; anddetect the network breakage in the wired communication network if no response is received from the damper after the retransmission of the data message the predetermined number of times.

17. The device according to claim 15 or 16, further comprising a switching device controller coupled to the at least one switching device,wherein in response to detecting the network breakage in the wired communication network, the control unit is configured to transmit a command to the switching device controller, the switching device controller is configured to:transmit a control signal to the at least one switching device to control the at least one switching device for said transmission of the data message; andin response to receipt of the command, transmit a further control signal to the at least one switching device to control the at least one switching device for said retransmission of the data message.

18. The device according to any of claims 15 to 17, wherein the wired communication network is configured to communicate data in accordance with a first communication protocol, and the control unit is coupled to the at least one switching device, and is configured to transmit the data message to the at least one switching device in accordance with the first communication protocol.

19. The device according to claim 18, wherein the control unit is configured to receive the data message in accordance with a second communication protocol, the second communication protocol different to the first communication protocol.

20. The device according to claim 19, wherein the second communication protocol is one of:Universal Serial Bus (USB) communication protocol;Universal Asynchronous Receiver / Transmitter (UART) communication protocol; orRS-232 communication protocol21. The device according to any of claims 18 to 20, wherein the first communication protocol is RS-485 communication protocol.

22. A method of controlling data transmission from a damper control device to a wired communication network to which is connected one or more dampers, the method comprising:controlling at least one switching device for transmission of a data message, via the at least one switching device, to a first end of a communication bus of the wired communication network, wherein the at least one switching device is coupled to (i) the first end of the communication bus of the wired communication network, and (ii) a second end of the communication bus, the second end opposing the first end;detecting a network breakage in the wired communication network; andin response to the detection, controlling the at least one switching device for retransmission of the data message, via the at least one switching device, to the second end of the communication bus.

23. A non-transitory computer-readable storage medium comprising instructions which, when executed by at least one processor cause the at least one processor to perform the method of claim 22.

24. A system comprising:a damper control device;a wired communication network to which is connected one or more dampers; andthe device according to any of claims 1 to 21.

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