Control system for energy saving system with wireless communication

The invention relates to a control system for energy saving system with wireless communication according to claim 1.

Background

In buildings with a lot of rooms where it is desirable to save energy, energy saving systems are used. Energy saving systems exist today in many homes, industrial and commercial buildings. Today, there is a high need for reducing the energy consumption, both in order to save costs and in order to reduce energy consumption.

There exist many systems which monitor, calculate and control electrical devices. It is today common to utilize the existing wiring to send information between electrical devices and the control unit of the system. There also exist systems where wireless sending of information between different units is used. The energy saving systems provide opportunities for controlling, for example, the temperature over a 24-hour period and the power consumption for heating is substantially reduced by lowering the temperature in the house, or parts of it (zones), at certain periods of time. Usually, in the night and otherwise in periods when the house or room is not in use. The monitoring and controlling is performed by means of a central unit which has associated external units which are controlled by the central unit. Examples of such external units are electric heaters or other electrical devices that exist in a common home. An energy saving system like this is usually connected to the existing electrical wiring.

The central unit has preferably a display and provides opportunities for programming of the desired temperature in zones or in the individual room.

Today, temperature control is known where communication between the central unit and the external units is performed via the existing electrical wiring or wireless network (radio).

DE 20 2005011517L ⁾ is a utility patent which includes an electronic heating cost distributor which has an electronic temperature sensor with memory and a bidirectional RF transponder. The field of use is cost calculation. The RF communication is used to transfer the calculated result.

US 2004/0177629 A1 describes a system for regulating the temperature in several areas within a building by use of several energy saving devices which regulate the temperature within a building which has a central heating and cooling installation. US 2005/0102068 A1 describes a remote control system for controlling of the consumption of a number of consumers. The main object here is to control the electrical devices to prevent peaks in the power network.

US 6 904 385 B1 describes a multi opportunity energy saving system with an internet energy platform.

FR 2 732 755 relates to a control unit for electrical radiators for controlling the room temperature. It uses an independent room thermostat which sends information to a radiator via for example wireless communication.

FR 2 779 024 relates to room control by means of an electrical convector and to collective control of all the convectors.

EP 1 160 752 relates to remote control of a direct-fired boiler by means of wireless communication. The problem with the mentioned publications is that if an external unit is arranged in a place where the wireless communication does not work, for example, outside the range of the central unit, then the information can not be sent or received. The external unit can thus not be controlled individually by the central unit via wireless communication.

Object

The object of the invention is to provide a control system for an energy saving system for monitoring and controlling of electrical devices, preferably temperature control of electric heaters, by use of wireless technology with a unique configuration which solves the above mentioned problems. It is also an object to provide a solution that requires as few components as possible, and that provides a secure solution which ensures that all the external units can communicate with the central unit without any need for extra actions and at the same time provides as low production costs as possible.

The invention

A control system for an energy saving system according to the invention is described in claim 1. Further details of the invention are described in the remaining claims.

The control system includes a central unit and at least one external unit in the form of an electric device, for example, an electric heater. The central unit communicates with the external unit(s) by means of wireless communication. The control system provides a dynamic configuration of the network, seen in relation to the controlling of the system. The system utilizes a bidirectional wireless communication where all the units (both central unit and external units) have unique addresses/ID codes. All external units must be made known in the central unit when the system is configured, in order to make a dynamic configuration of the network possible. If the direct communication between the central unit and the external unit fails, the central unit will try to establish communication via the other

external units where communication already is established. This can also be done in several links such that the range can be increased further. This provides the system with a great advantage, since it makes it easier to re-arrange, needs no wiring, just one unit which is connected to the existing electric unit. The system can thus also be used to monitor electrical devices which are not connected to the same wiring or which for other reasons does not have contact with the central unit, for example, is out of range of the wireless communication. The dynamic configuration of the system makes the system also dynamic in relation to fault situations. If one of the communication lines fails, the system will automatically rearrange the communication lines by arranging other external units as links.

The system is also provided with anti-collision means ("Listen before talk"), such that the signals are not interrupted by signals from other units associated with the same system.

The system is arranged to monitor and control the electrical units.

Further details of the invention will appear form the following example description.

Example

The invention will now be described in detail with reference to the Figures, where

Figure 1 shows a schematic overview of a control system for an energy saving system according to the invention, Figure 2 shows the system of Figure 1 , without direct connection between one of the external units and the central unit, and

Figure 3 shows an example of a communication unit for arrangement in relation to an electrical device.

Figure 1 shows a control system for an energy saving system according to the invention, which system 1 includes a central control unit 10 and four external units 11A ₁ 11 B, 11 C and 11 D, for example, electrical heaters. The central control unit 10 is usually located in a central place in a building, which is easily accessible and visible. The external units 11 A, 11 B, 11 C and 11 D are in the example electric heaters, which are located in different rooms in a building. Both the central control unit 10 and the external units 11 A, 11 B, 11C and 11 D are connected to the existing power network and supplied with power therethrough. The central unit 10 (and the external units 11 A, 11 B, 11C and 11D) is in addition preferably provided with a rechargeable battery to maintain status during, for example, power failure. Since they are provided with power also at power failure, this result in that the control unit 10, as the power comes back, can supply the external units 11 A, 11 B, 11C and 11 D with adequate settings to obtain the correct temperature in a room in a building, quickly and effectively.

The central control unit 10 and the external units 11 A, 11 B, 11 C and 11 D are further provided with communication means 20 for sending and receiving of information. These communication means 20 includes preferably bidirectional sending by means of RF antennas (described below). The system preferably also includes anti-collision means to prevent information that is sent and received being interrupted by other signals. The anti- collision means are preferably of the type "Listen before talk" and are arranged in the software of the different units. The communication means 20 are arranged on the external units 11 A, 11 B, 11C and 11 D by means of units 30 (shown in Figure 3) to provide the external units 11 A, 11 B, 11C and 11 D with the desired properties. The system is further configured and utilizes a unique addressing, i.e. that each unit (10 and 11A, 11 B, 11C and 11 D) is provided with different ID codes which makes them recognizable in the system.

References are now made to Figure 2, which shows a schematic overview of a system according to the invention, where the central unit 10 is without contact with the external unit 11 D, for example, because it is located outside the range of the wireless communication of the system. The system includes for this a dynamic configuration, which by means of an algorithm and a dynamic stack/table provides a dynamic link function for the system. This means that the system establishes communication lines between the central unit and the external unit 11 D via other external units 11A-C, where communication already is established between the external units 11A-11C and the central unit 10.

The system is arranged in the way that the central unit 10 controls all communication, which means that the external units 11A-D never try to achieve contact with the central unit 10 unless they are asked to do so by the central unit 10. The central unit 10 is, as mentioned above, provided with a dynamic stack/table, for example, as shown in table 1 and table 2 below. The table includes a column for all the external units in the system, by means of their unique ID codes. The table includes further a column for direct communication, a column for no communication, and a column for linked communication. Since the table is dynamic, it will at all times be updated and have full overview over the external units 11A-D with which direct contact can be achieved, external units 11A-D with which direct contact cannot be achieved, and external units 11A-D with which contact can be achieved via other external units 11A-D, i.e. linked.

The external units 11A-D are first made known in the central unit 10 by entering their unique address (ID code) in a setup procedure. After the setup procedure and at update, the central unit will by means of an algorithm search for the external units and find out if they can be reached directly. If the external unit can be reached directly, a value D is inserted in the table for the actual external unit. For external units which cannot be

reached, a code X is inserted in column two, which indicates that the external unit can not be reached.

After the central unit has found out if it has direct contact with the actual external units or not, it will try to establish contact via the other external units to reach the external unit(s) that could not be reached directly. This can be done by the central unit trying to communicate through each of the external units that can be reached directly. Preferably, the central unit starts at the top of the table and works successively down the list of the external units. As the communication between the external unit, which can not be reached directly, and the central unit is established through one of the external units that can be reached directly, the table is updated in the column for linked communication with the address of the external unit through which there is established contact, as, for example, is shown in table 2.

This makes the system, as mentioned, dynamic in relation to fault situations. If one of the communication lines fails, the system will automatically re-arrange the communication lines and arrange other external units as links.

For linked communication, the address of the external unit which is not reached directly is transmitted to the external unit that is used as a link. This forwards the information to the linked unit together with its own address, and also the address of the central unit - thus, the communication path (both ways) is established, from the central unit 10 and the linked external unit.

An example will now be described with references to Figure 2 and table 1 and 2. In the shown example the central unit first tries to establish contact with the external units 11A-D. Since the central unit achieves direct contact with the external units 11A-C, the table is updated with a D for each of the external units in the column for direct communication. Since the central unit 10 does not achieve contact with the unit 11 D, the table is updated with a code X in column two for the external unit 11 D, as shown in table 1. As the central unit 10 does not achieve contact with the external unit 11 D, the central unit 10 tries to establish contact through the other external units 11A-C which already have direct contact with the central unit 10. Since there is no contact between the external unit 11A and the external unit 11 D, the central unit 10 moves on and tries to establish contact between the external unit 11 B and the external unit 11 D. Since contact here can be achieved, the table is updated in column three for linked communication with the address (ID code) of the external unit 11 B for the external unit 11 D ₁ as shown in table 2. A link function between the external unit 1 1 D, via the external unit 11 B, and the central unit 10 is thus established.

Table 2

References are now made to Figure 3 which shows a more detailed overview of the units 30 which are used to provide the external units 11 A, 11 B, 11 C and 11 D and the central unit 10 with the communication means 20. The unit 30 includes preferably a printed circuit board 31 which preferably includes an energy supply 32, a CPU 33, input means 34, output means 35, a RF chip 36, a low-pass filter 37 and a RF antenna 38. The input means 34 can include, for example, buttons for manual settings, external units such as temperature meter or electric meter, etc. The output means 35 can include, for example, a display, actuators, etc. The CPU 33 controls when information is sent and received. The CPU 33 performs control of the I/O units. The CPU 33 communicates with the RF chip 36. The CPU 33 further maintains the general functionality, depending on the product. At start-up, the CPU 33 configures the RF chip 36 with regard to parameters which it needs, such as transmitting frequency, protocol size, etc. The antenna 38 is preferably a loop antenna and the low-pass filter 37 tunes the antenna. This combination is preferable in that few components are needed and there is little interference. The function of the RF chip 36 is to pack data from the CPU 33. The clock frequency of the RF chip can be independent of the clock frequency of the CPU 33, which means that the requirement for speed of the CPU 33 can be reduced, something that results in a reduced cost of the CPU 33.

The RF chip 36 includes TX/RX functionality (Transmit/Receive Switching) including listen before talk function.

In addition the RF chip functions include filtering of relevant information at reception - i.e. checking if the message sent is to this unit.

The communication unit 30 stands in a normal mode and listens if it is supplied with information intended for the actual external unit 11A-D. And if it is supplied with information, the information is processed by the CPU 33 and actions are performed. Examples of such actions can be changes of settings or instructions of sending temperature measurements and similar.

References are again made to Figure 2 for a description of general communication. For systems with a central unit 10 and external units 11A-D, it is, in energy saving systems, weekly programs or status changes as a consequence of, for example, oversteering in the central unit 10 that decide when the communication shall be performed. Due to feedback from the external units 11A-D (confirmation through bidirectional communication) when the status changes occurs, there is no need for frequent updates between status changes.