Increased energy prices bring about a need for improved energy control in, for example, buildings.

The traditional cable-dependent adjusting of energy consumption provides little flexibility when carrying out room changes, for example.

It is known to adjust energy consumption by means of a wireless connection. Thus, WO 99/49680 describes a method for monitoring and controlling equipment in buildings by means of

communication networks, such as a Global system for mobile communication (GSM).

US 5.926. 776 concerns a thermostat containing control logic and a transceiver that communicates with an electricity supplier, the thermostat receiving information concerning the prevailing electricity price, and the thermostat setpoint being controlled based on the prevailing electricity price.

Relative to prior art, the object of the invention is to disclose a method for providing a more flexible and suitable way of monitoring physical parameters, such as room temperature, outside temperature, weather condition, gas-and water leakages, etc. , and for adjusting, for example, energy supply to, for example, heating based on the measured parameters and submitted values.

According to the invention, the object is achieved by means of features disclosed in the following description and in the subsequent claims.

According to the invention, a number of nodes are placed in suitable positions to monitor and to adjust the desired parameters. The nodes may be stationary or moveable.

The nodes are provided with control logic and a transceiver and are arranged for wireless and encrypted communication with each other. At least a portion of the nodes is provided with a device for measuring one physical parameter, for example temperature. The nodes may be provided with a mechanical or semi-conductor switch for adjusting, for example, electricity supply to a heater.

At their own accord, the nodes are arranged for wireless communication by means of standards for short-range radio communication known per se, cf. description below. This type of radio communication has proven suitable for use, owing to the material being available at an acceptable cost in view of the object at hand, and owing to such equipment having a small, radiated power, thus having a low power consumption.

Communication of this type, however, may be contingent upon use of relay nodes to achieve the desired range.

From a production point of view, it is preferable that the nodes be manufactured as identical as possible, regardless of their function in the monitoring-and control system. Thus, the nodes are programmed during the installation to comprise a control node, an area control node, or a controlled node, respectively. A controlled node may serve as a relay node, a measuring node, an executing node or combinations thereof.

For example, a node installed in a socket may be programmed for on/off switching of the electricity supply to the socket, for measuring the energy consumption via the socket and for being a relay node. All nodes are arranged to register and to communicate their own status to the control node.

Usually, it is appropriate to provide a superior control function to one control node. The control node comprises, or is associated with, an input-output node connected to a device for communication with the user or with an external data network in the form of, for example, a computer or a telephone. As a minimum, the control node must be connected to a keyboard for entering parameters, and a display unit arranged for showing set values, present values, possibly also the history and forecasts for chosen parameters.

Groups of nodes may be arranged in an area network. For example, an area control node may control the temperature in a room if the control node malfunctions. During normal operation, the area control node maintains the tasks of a control node within the area network. The control node controls the area control node for the entire network.

The information path from one node to another node is determined by means of so-called"routing", as known per se.

An overview of possible routes from the control node to, for example, a controlled node may be in the form of a table in the control node. If one relay node malfunctions, the control node will detect this, possibly setting off an alarm, and selects an alternate route.

The information exchange between the nodes is encrypted.

Among other things, encrypted communication is necessary to prevent adjacent networks from assuming control of the nodes, and also for security reasons, inasmuch as it is conceivable that outsiders may attempt to disturb the function of the node network.

Encryption known per se is used, each node network being assigned a unique network key registered in all nodes of the network, and a key being changed sequentially with time.

When a measured parameter is changed, for example, or when a preset time interval has expired, unsolicited information to this effect is transmitted to the control node. If a measured value falls outside a preset area, the control node may be programmed to recognize this as an alarm condition, subsequently initiating an alarm procedure.

Additional to the information to be transmitted, a message from, for example, the control unit comprises at least a transmitter and receiver identification and address that determines, by means of the routing, which route the message will take, and which node the message is intended for. The message also comprises an encrypted portion comprising the static code identifying the network and the variable code.

Thus, it is not possible for a foreign control node to assume control of a node in a network. It is possible, however, to use a controlled node in a neighbouring network as a relay node for communication without disturbing the functions of the neighbouring network.

By allowing messages between the nodes to comprise source- and destination addresses and not transmitter and receiver addresses, the message must be combined with the routing table in order for the message to reach the correct destination address. The addresses of the controlled nodes, which constitute relay nodes, do not form a part of the message itself. Thus, it is possible to transmit messages via relay nodes that are not part of the node network at hand.

This is due to foreign relay nodes not having to interpret the contents of the message, but merely conveying it to the next node.

The nodes may be provided with necessary operational energy from the electricity network, local emergency electricity networks, solar energy or from their own batteries. The frequency of receiving and transmitting messages significantly affects the energy consumption of the nodes.

The response time and energy consumption of individual nodes

is adjusted by determining, among other things, how often the node is to handle messages. For example, having a relatively long response time is acceptable when the room temperature setpoint is to be changed, whereas a short response time is necessary for switching lighting off or on.

On the basis of collected measurement values and information provided about the object to be energy-controlled, forecasts may be generated automatically as an aid to the user.

Measuring and summarizing energy consumption values from nodes within one area may render unnecessary to install a separate energy meter for measuring the energy consumption in, for example, an apartment or a section.

The user may receive information from or submit control data to the node network via cabled or wireless apparatuses, for example a telephone or a computer.

In the following, a non-restricted example of a preferred embodiment is described and depicted on the accompanying drawing, in which: Fig. 1 schematically shows a node network according to the invention, in which arrows indicate wireless communication between the nodes.

On the drawing, reference numeral 1 denotes a node network comprising a control node 2, an area control node 4, controlled nodes 6 and an input-output node 8.

The nodes 2,4, 6 and 8 communicate mutually by means of relatively short-range radio communication.

When operation of the node network according to the invention is to be initiated, each of the nodes 2,4, 6 and 8 is assigned, through programming, a service and a function within the node network 1, an address and the fixed network encryption key.

The nodes are installed in their respective positions that, for a switch-type controlled node 6, may be in a socket (not shown), in a heater (not shown) or in association with valve (not shown) or similar, in which it is arranged to control the energy consumption and to report back to the control node 2 about, for example, switch position and energy consumption.

A registration-type, controlled node 6 may be placed outside to measure physical values, for example, such as temperature and solar intensity.

When the node network 1 is turned on, the control node 2 will initiate a self-configuration at first, in which the other nodes 4,6 and 8 are surveyed. The surveying is carried out in that the control node 2 contacts all the controlled nodes 4,6 and 8 and asks each node 4,6 and 8 for identification with respect to identity and function. The inquiry from the control node uses the unique, fixed encryption code of the network and an electronic signature. Controlled nodes 4,6 and 8 not recognizing this fixed encryption code, hence not recognizing the electronic signature of the control node 2, ignores the inquiry from the control node 2 and thus is not accepted as a part of the node network. A routing table for communication between the nodes 2,4, 6 and 8 is determined either automatically or, alternatively, is submitted by the user.

After having established the nodes 2,4, 6 and 8 incorporated in the node network 1 as a node network 1, messages are transmitted between the nodes 2,4, 6 and 8 in an encrypted form, also incorporating a variable encryption key.

The node network 1 may comprise an area node network 10. If the connection to the control node 2 malfunctions, the area control node 4 will assume control of the controlled nodes 6 within the area node network 10.