A CONTROL AND REGISTRATION SYSTEM

Abstract: The invention relates to a control and /or registration system (1), comprising a host computer (VD) which monitors the system either directly or indirectly, and a number of pieces of equipment or the like which are monitored by the host computer and which are supplied with voltage from one and the same mains voltage supply system (10), wherein the monitoring host computer (VD) can communicate, either directly or indirectly, with each of said monitored pieces of equipment (11), wherein each of said monitored pieces of equipment (11) can communicate, either directly or indirectly, with said host computer (VD) via information-carrying signals (12) which are adapted for transmission via the mains voltage supply system (10). A master unit (2) associated with the host computer is connected between the host computer (VD) and an electric contact device or outlet (10a) belonging to the mains voltage supply system (10). A satellite unit (3) associated with a piece of monitored equipment (11) or the like is connected to an outlet (10a') belonging to the mains voltage supply system (10). The master unit (2) functions to check the connection of each satellite unit (3, 11) by sending information-carrying signals (12) to and receiving information-carrying signals (12) from the satellite unit (3), and the master unit (2) functions to register and/or causes the host computer (VD) to register all monitored pieces of equipment (11). The host computer is also constructed to allocate to each connected satellite unit an identity within the system.

Description: TITLE OF THE INVENTION: A CONTROL AND REGISTRATION SYSTEM TECHNICAL FIELD The present invention relates to a control and/or registra¬ tion system of the kind which includes at least one system monitoring host computer and a plurality of system equipment or system objects that are capable of being monitored. The present invention is based on the presumption that the host computer and each of said pieces of equipment or objects shall be supplied with voltage taken from one and the same mains voltage system. The invention is also based on the assumption that said monitoring host computer shall be capable of communicating with each of the monitorable and monitored pieces of equip¬ ment, either directly or indirectly, while each of said monitored pieces of equipment is able to communicate with the host computer, either directly or indirectly, through the medium of information-carrying signals which are adapted to a carrier frequency or the like such as to enable said signals to be transmitted and perceived by transmission on the electrical conductors of said mains voltage supply system. More particularly, the present invention is intended to provide a control and/or registration system which can be readily supplemented in a manner to provide a relevant inventory register over all of the monitorable and/or monitored pieces of equipment. Thus, the inventive system enables the presence of monitored equipment to be monitored continuously, by connecting-up said equipment. The inventive system also enables in addition (or solely) monitoring of a piece of equipment, an object, apparatus, or the like, whose function does not require the availability of a mains voltage supply system, and therewith create conditions for constructing an alarm-activating system which will activate an alarm should the monitored equipment be stolen or be removed with no criminal intent. DESCRIPTION OF THE BACKGROUND ART Several different types of control and/or registration systems that include a monitoring unit or host computer and a plurality of pieces of equipment or objects that can be and/or are monitored by the host computer are known to the art. For instance, it is known to use in fire-monitoring systems a central unit or host computer which senses sequentially a plurality of measuring points and activates an alarm system immediately upon detecting that one of the measuring points has been switched from a non-fire-indicating position to a fire-indicating position. Similar systems intended for other monitoring purposes are also known to the art, such as a burglary alarm systems, a security alarm systems, monitoring systems and the like. With regard to the fundamental qualifications of the present invention, it can be mentioned that there are known to the art different systems for transmitting information-carrying signals over a mains voltage supply system with the aid of a carrier frequency. Reference is made to U.S. Patent Specification 4,513,382 as an example of the present standpoints of techniques in this regard. With regard to the present standpoint of techniques concern¬ ing different inventory registers, it is previously known to store in a computer unit significant information relating to respective inventory objects as one item and to insert manually into the register each new inventory item and/or remove an earlier stored inventory item manually from the register. The inventory list stored in the computer unit can thus be read and/or printed-out, by activating circuits adapted therefore. Reference is also made to the subject matter of the following publications, with regard to the earlier standpoint of techniques. 0-A193/11515 This publication describes a security system in which diverse security units are used to monitor electronic equipment which may be connected to a common mains voltage supply. One type of security unit (10) may be connected to the equipment to be monitored. This security unit includes an individual identity code which is unique to the security unit and therewith also to the equipment to which it is connected. A further security unit (20) is fitted into the wall socket (14) to which the monitored equipment is connected to the mains supply voltage. This security unit (20) also has its own identity code. A central computer (30) is connected to the same voltage supply and "polls" the monitored equipment via the voltage network. The security unit 10 responds to the security unit 20, which in turn responds to the central computer. The central computer is thus not only able to ascertain that a given piece of equipment is connected but also to ascertain to which wall-socket the equipment is connected. The common voltage supply network is used for transmitting the communi¬ cation. EP-A2 0 456 395 This publication describes a security system for monitoring a number of personal computers, computer terminals or other computer systems which are supplied with voltage from a common voltage supply network. The security units provided in respective computers are comprised of a modem which functions to transmit and receive information over the voltage supply network. Remaining functions are embodied in the computer software and the internal processors and memories used. Communication between respective computers is effected in a manner similar to that normally used in so-called LAN networks (Local Area Networks), with the difference that transmission takes place over the standard voltage supply network instead of over a dedicated communication network. US-A 5,034,723 This publication describes a monitoring system in which monitored equipment (4) is connected to the general voltage supply network, via a special cable (1) and an alarm unit (3). The alarm unit (3) is in contact with a control station (11), via communication over the general voltage supply network. The special cable (1) is constructed so that the alarm unit is able to detect when the cable is disconnected from the equipment (4) or if the cable has been cut. When such an event occurs, the alarm unit alarms the control station via the voltage network. US-A 4 , 410, 883 This publication describes a multiple signal system in which a number of remote units are in contact with a main unit via a voltage supply network located in a building. The system is different to any of the aforedescribed systems and to the present invention, since the system is intended to transmit signals from a number of different types of remote units. These units can be intended for sound transmis¬ sion, the transmission of alarm signals for different types of alarms, such as a fire alarm, smoke detection, water level alarm, or a call for medical help, or the transmission of control signals for different control systems, such as control systems for heating systems or air-conditioning systems. Each control unit communicates with the main unit over a unique frequency band, which is the modulation frequency used in the communication process. A total of ninety-nine differ¬ ent frequency bands are used. The system can be configured so that one remote unit will transmit a signal continuously and so that an interruption in the signal will be noticed by the main unit, which will then activate an alarm of one kind or another. Alternatively, a remote unit begins to transmit only when wishing to draw attention to the fact that an alarm situation has risen, instead of transmitting a signal continuously. Each remote unit is identified by a unique transmission frequency and a unique identity number. A remote unit may, for instance, be a portable unit carried by a cleaner who after having cleaned a room connects his/her portable unit to the mains and keys-in the specific number of the room on a number selector pad on the remote unit, therewith sending to the main unit a signal to the effect that the room has been cleaned. In this regard, one control unit can be used with several different identity numbers (room numbers), wherein the main unit identifies the transmitting remote unit, through the medium of the transmission frequency, and the room from the signal is sent, by the room number. It is obvious that each remote unit must be allocated a specific transmission frequency before being able to estab¬ lish communication between the remote unit and the main unit. It is also evident that the various units are allocated a respective transmission frequency and identity number, with the aid of a hardware selector, such as dip switches or rotary switches, which is done manually for each individual control unit. SUMMARY OF THE INVENTION TECHNICAL PROBLEMS When considering the present standpoint of techniques as described above, it will be evident that a technical problem resides in the ability to create an automatically controlling and/or registering system with the aid of simple means, and to provide such a system which can be readily supplemented to include a temporarily relevant inventory register via monitorable and/or monitored objects, apparatus or pieces of equipment. Another technical problem is one of being able to monitor mains-»connected equipment in a simple manner. It will also be evident that a further technical problem is one of enabling objects that do not need to be connected to a mains supply to be functional, but which are placed close to a mains outlet, for instance such as pieces of furniture and the like. Another technical problem is one of providing a controlling and/or registering system which can be readily adapted and used for chosen inventory items that are located physically within an area covered by the physical conductors of an existing mains voltage supply system, and to use this mains voltage supply system for the purpose of transmitting information-carrying signals. Another technical problem is one of realizing the signifi- cance of using a master unit which can be connected readily between the host computer and a mains connection. A further technical problem is one of realizing the signifi¬ cance of being able to use a satellite unit which can be readily connected between equipment, to an object, apparatus or the like, and a mains connection. It is also evident that a technical problem resides in realizing the potential advantages of an inventory system when it is possible to transmit information-carrying signals between a host computer and/or a master unit connected to said host computer, and each of the monitorable and/or monitored pieces of equipment or objects in order to allocate an identification code thereto. It will also be seen that another technical problem is one of creating conditions wherein the construction of the inventive system requires solely the use of one master unit belonging to the host computer, and at least one satellite unit corresponding to the number of monitored pieces of equipment or objects, wherein one single satellite unit is allocated to one piece of equipment or one object. In addition to the aforesaid problems, another technical problem is one of realizing other conditions for creating an inventory system of the kind defined in the introduction solely by using one simple connectable master unit and one or more simple connectable satellite units. A further technical problem resides in the realization of those conditions that are required to permit the master unit to include solely one electric contact device (female contact) adapted to mains voltage, and an electric contact device (male contact device) adapted to the computer unit. It will also be seen that a technical problem resides in realizing those advantages that are afforded when a satellite unit belonging to the monitorable or monitored equipment can be connected between a mains voltage-related (male) contact device associated with each piece of equipment and a (female) electric contact device associated with the mains voltage system assigned to a piece of equipment, and to permit one such satellite unit to be comprised of a discrete unit which initially does not have the identity of the equipment or object being monitored. Another technical problem is one of realizing the advantages that are afforded when the satellite unit is not allocated a system-related and/or equipment-related identity by the master unit until said equipment or object is connected to said master unit. Another technical problem is one of realizing the conditions that are necessary in order to enable each satellite unit to be loaded with two mains-voltage adapted electric contact devices, a male electric contact device and a female electric contact device, and therewith also realize the conditions that are required to indicate when a piece of equipment is connected or that an object is intact, or vice versa. Another technical problem is one of realizing the advantages that are afforded by allowing the master unit belonging to the host computer to be connected between a host-computer communication port and a mains-voltage system outlet, wherein the master unit has the form of a discrete component. Still another technical problem resides in the ability to realize the significance of permitting a readily connectable master unit to be constructed so as to be able to check through an internal circuit arrangement and/or via the host computer that an accepted connection of each monitored piece of equipment or the like has been effected, by adapting the master unit to transmit information-carrying signals to and receive information-carrying signals from each of the monitored pieces of equipment so as to establish the status of said equipment, by waiting for and registering response signals from each of said pieces of equipment subsequent to activation in an ordered manner, and to activate an alarm signal in the absence of any such response. Another technical problem is one of realizing the signifi¬ cance of registering the absence of any response immediately, and recording this absence in an inventory list. Still another technical problem is one of realizing the significance of constructing the master unit to register all monitorable and/or monitored equipment or objects and/or to cause the host computer to effect such registration. Because the inventive system is able to use solely one single master unit and preferably a relatively large number of satellite units, where each of said units can be readily connected to the mains voltage supply system and to the host computer and to respective monitored equipment or objects, it will be seen that a technical problem resides in realizing those advantages that are afforded when it is possible to allocate a satellite unit and/or a monitored piece of equipment a system-related equipment-significant identifying code by the master unit, when the satellite unit and the piece of equipment are connected. It will also be seen that a technical problem is one of creating in a simple way conditions such that immediately an information-carrying connection between the master unit and/or the host computer and one of the satellite units and/or the monitored piece of equipment and/or the object and/or the current supply is broken for a longer or shorter period of time, that this happening can be indicated quickly within the master unit and that the broken connection can be shown on a host-computer display screen. It will also be seen that a technical problem resides in creating with the aid of simple means conditions and satel¬ lite-unit construction directives which will enable the satellite unit to include, among other things, a communica- tion part which when transmitting information-carrying signals in response to an enquiry from the master unit is also able to transmit its identification code allocated by the master unit. It will also be seen that a technical problem is one of realizing the advantages that are afforded when allowing the host computer to include an inventory system in which each monitorable and/or monitored unit is included as an item together with the identification code of said unit and information relating to the connection or disconnection thereof, and where a selected satellite unit and/or monitored piece of equipment or object can be indicated as temporarily or definitely disconnectable, via the host computer. It will also be evident that a technical problem is one of realizing the significance of permitting one main host computer to be connected to one or more host computers, wherein the main host computer is able to store all satellite units and/or monitorable and/or monitored pieces of equipment or objects related to respective host computers, and particu¬ larly such pieces of equipment, objects and/or items which have once been connected but not removed from the inventory register of the main host computer. SOLUTION With the intention of solving one or more of the aforesaid technical problems, the present invention takes as its starting point a control and/or registration system which comprises at least one system-monitoring host computer and a plurality of pieces of equipment or objects which can be monitored and/or which are monitored by the host computer, wherein the host computer, and preferably each of the pieces of equipment or objects, is supplied with voltage from one and the same mains voltage supply system, wherein said monitoring host computer is able to communicate with each of said monitorable pieces of equipment or objects via informa¬ tion-carrying signals, and wherein each of said monitorable pieces of equipment or objects is able to communicate with said host computer via information-carrying signals, said signals being adapted for transmission on electric conductors within said mains voltage supply system. In such a system, a master unit belonging to the host computer can be connected and is connected between the host computer and a (female) electric contact device or outlet belonging to the mains voltage supply system, and a satellite unit associated with a monitored piece of equipment or object can be connected and is connected to a (female) electric contact device or outlet belonging to the mains voltage supply system, wherein the master unit functions to control the connection of each monitored piece of equipment or object by sending information-carrying signals to and receiving information-carrying signals from said monitored equipment or objects, and wherein said master unit functions to register at least all monitored equipment and/or causes the host computer to register at least all monitored pieces of equipment. According to the present invention, the master unit functions to assign an identification code to the satellite unit and/or to the piece of equipment or objects when connecting-up a satellite unit associated with a monitored piece of equipment or object. Pursuant to further developments of the invention that lie within the scope of the inventive concept, it is proposed that when the connection between the master unit and a satellite unit and/or a monitored piece of equipment or object is broken, this will be indicated within the master unit. It is also proposed within the scope of the invention that a broken connection to a satellite unit and/or a monitored piece of equipment is indicated on the display screen of the host computer, and that this information will include data relating to the location of the satellite unit and/or the monitored piece of equipment or object, and also the time at which the connection was broken. When it is established that a connection has been broken, an alarm device can be activated, wherein the alarm device may be related to the master unit and/or to the satellite unit. According to another embodiment of the invention, the satellite unit also includes a communication part which when transmitting information-carrying signals to the master unit also sends an identification code previously allocated to the satellite unit by the master unit. The host computer and/or the master unit may include an inventory system in which each monitorable and/or monitored satellite unit with allocated identification code is insert- ed, and also such information as time data relating to activation or deactivation of the satellite unit. A chosen satellite unit and/or a monitorable or monitored piece of equipment may be registered via the host computer as being temporarily disconnected or definitely disconnected. According to another embodiment of the invention, one or more of the aforesaid host computers is/are connected to a main host computer in which all satellite units and/or all monitorable and/or all monitored pieces of equipment are stored, and particularly those which have been connected at one time but have not been removed from an inventory regis¬ ter. ADVANTAGES Those advantages primarily afforded by an inventive control¬ ling and/or registering system reside in the creation of conditions which enable the master unit to allocate an identification code to a satellite unit when connecting-up said unit through the medium of discrete components, and by creating conditions through a master unit connected to the host computer and through a satellite unit connected to each piece of monitored equipment such that an alarm signal will be generated immediately at least one satellite unit or at least one monitored piece of equipment or at least one object is disconnected from the mains voltage supply system, unless this disconnection has earlier been accepted by the host computer. In addition, the identity of pieces of equipment and objects that have earlier been inserted into an inventory register can be readily removed therefrom and other pieces of equip¬ ment and objects inserted therein in a simple fashion. This provides for a simple and positive instantaneous inventory of each piece of monitored equipment or each monitored object in operation, and also enables monitorable pieces of equip¬ ment or objects to be temporarily disconnected. The primary characteristic features of an inventive control and/or registration system are set forth in the characteriz¬ ing clause of the following Claim 1. BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of an inventive control and/or registration system having features significant of the invention will now be described with reference to the accompanying drawings, in which Figure 1 is an overview of an inventive system; Figure 2 illustrates two different embodiments of a master unit connectable to the host computer; Figure 3 illustrates two different embodiments of a satel- lite unit that can be connected to monitored equipment; Figure 4 illustrates a principle construction of the sys¬ tem; Figure 5 is a block schematic illustrating a master unit; Figure 6 is a block schematic illustrating a satellite unit; Figure 7 is a block schematic illustrating a control unit included in the master unit; Figure 8 is a block schematic illustrating a control unit included in the satellite unit; Figure 9 illustrates a satellite unit according to Figure 3B in more detail; and Figure 10 illustrates part of a (female) electric contact device according to Figure 9 belong to the satel¬ lite unit. DESCRIPTION OF PROPOSED EMBODIMENTS Figure 1 thus illustrates a control and/or registration system which includes the characteristics of the invention and which comprises a host computer VD and a number of pieces of equipment and/or object SN monitored by the host computer. By "pieces of equipment" is meant electrical or electronic equipment whose function requires the supply of voltage from a mains voltage supply system. By "object" is meant a piece of equipment or some other element whose function does not require the supply of voltage. The system may include monitorable and monitored pieces of equipment and/or objects, i.e. equipment and objects that have been monitored and equipment and objects that are able to be monitored, and monitored pieces of equipment and/or objects that are monitored at that point in time. The host computer VD is connected to a mains voltage supply system through the medium of a connection line provided with a (male) electric contact device, not shown. One significant feature of the present invention is that the host computer VD is connected to or joined with a master unit 2 by a conductor 2a, said master unit being provided with the requisite voltage supply from a mains voltage supply system 10, through a cable connector 2b. The mains supply system 10 is illustrated as a system with 220 VAC, although other voltages may be used without depart¬ ing from the principle construction and function of the invention. The host computer VD is supplied with voltage from a mains voltage supply system, through a cable connector, not shown. This mains voltage supply system may be separate from the mains voltage supply system 10, although it is assumed in the present case that the host computer VD is supplied from the system 10. As the present invention can be explained effectively with the aid of one single monitored piece of equipment or one single monitored object, only one of the illustrated monitor¬ able pieces of equipment SN has been identified with the reference numeral 11, this monitored piece of equipment 11 being connected to a satellite unit 3 which is provided with a cable or equivalent conductor 3a that connects the piece of equipment 11, and a cable or equivalent conductor 3b which connects the satellite unit to the mains voltage supply system 10. The satellite unit 3 is comprised of a discrete unit (Fig. 9), having a cable connector or equivalent conductor provided with a male electrical contact device 91 for coaction with the outlet of the mains voltage supply system 10, and a female electrical contact device 92 for coaction with the male electrical contact device on said piece of equipment 11, and an electronic unit 3, 93 orientated therebetween. The master unit 2 is comprised of a discrete unit having a cable connector or equivalent conductor 2b provided with a male electrical contact device for coaction with the outlet of the mains voltage supply system 10, and a cable connector or equivalent conductor 2a provided with an electrical contact device for coaction with the host computer VD. Figure 1 is intended to show that both the host computer VD and each piece of equipment SN such as the piece of equipment 11, is supplied with voltage from one and the same mains voltage supply system 10, and that the system related master unit and the system related satellite unit 3 are also supplied with voltage from the system 10. The monitoring host computer VD is able to communicate with each of said monitorable and/or monitored pieces of equipment 11, and each of said pieces of equipment 11 is capable of communicating with said host computer VD, through the medium of information-carrying signals. The information-carrying signals are adapted in a known manner for transmission over the physical conductors of the mains voltage supply system 10 through the medium of high frequency carrier waves, this being illustrated by a communi¬ cation route referenced 12. The transmission of information-carrying signals on the physical conductors of the mains voltage supply system is known to the art and will not therefore be described in detail here. In the present case, the information-carrying signal is allocated a carrier frequency or the like that deviates from and is much higher than the frequency of the voltage supply system. The host computer VD is thus connected to an associated master unit 2, said master unit being connected between a host-computer communication port 2a 1 and an outlet 10a of the mains voltage supply system. An equipment-monitoring satellite unit is connected between a male electrical contact device for the monitored equipment 11 and an outlet 10a' of the mains voltage supply system 10. This connection pattern and the communication route 12 enable the master unit 2 to check that each piece of monitored equipment 11 is connected correctly, by sending signals to the monitored equipment and receiving information-signals from said monitored equipment over the signalling route 12, whereby the master unit 2 functions to register all monitor¬ able and/or all monitored pieces of equipment and objects and/or causes the host computer VD to effect such registra¬ tion. Figure 2 illustrates two different embodiments of a master unit 2. The master unit 2 shown in Figure 2A includes a connection cable 2a, which in turn includes an electrical contact device 2a" adapted for coaction with a host-computer communication port 2a' , and a cable connector 2b which has on its free end a male electrical plug 10b intended for coaction with the socket outlet 10a of the mains voltage supply system 10. Figure 2B illustrates an alternative embodiment of the master unit, wherein said master unit 2 also includes a telephone connector cable 2c. Figure 3 illustrates two alternative embodiments of satellite units 3, where the satellite unit of Figure 3A includes one single connector cable 3b having fitted on one end a male electric plug 10b' for connection to the mains voltage supply system 10. The satellite unit 3 is intended primarily for such inventory items as tables, pictures, paintings, chests of drawers, and so on, wherein one surface of the unit 3 is so affixed to the inventory object as to activate a microswitch immediately the unit 3 is removed, and therewith activate alarm circuits, etc., within the unit 3, as a result of the change in state of the microswitch. Figure 3B illustrates an alternative embodiment which includes two connection cables 3b and 3a. One end of the connector cable 3b carries a male electric plug 10b' and the end of the connector cable 3a carries a female socket device 10c for coaction with a male plug related to a piece of equipment. Figure 4 is intended to show by way of example application of the invention with one single mains voltage supply system 10. The system includes a host computer VD, an associated master unit 2. The monitored equipment includes a telefacsimile machine 41 installed on the first floor of a building, a computer system 42 and a dictaphone 43 installed on a second floor of the building, and a computer system 44 and a telefacsimile machine 45 installed on a third floor of the building, each piece of equipment being monitored by a respective satellite unit 3. Each of these pieces of monitored equipment 41-45 is connect¬ ed to the mains voltage supply system 10 via its respective satellite unit according to Figure 3b. The system may also include other pieces of equipment in other buildings, such as data equipment 46a, a telefacsimile apparatus 46b and a telephone apparatus 46c. Installed on a second floor are data equipment 46d, a telephone apparatus 46e and a telefacsimile apparatus 46f. The system may also be expanded for use with and to monitor equipment of a nature that has not been assigned a reference numeral in Figure 4. It can be mentioned, however, that the system shown in Figure 4 can also function when a satellite unit, according to Figure 3A, is attached firmly to an inventory object or to a piece of equipment and the electric plug 10b' is inserted into the electrical socket of the mains voltage supply system. The invention also relates to an embodiment in which several systems work within the same mains voltage domain with different codes. Figure 5 is a block schematic illustrating a master unit 2 which comprises an electric mains interface 50, a power unit 51, an electric mains modem 52, a control unit 53, a memory 54, an adaptation circuit 55 and an interface against the host computer VD. Figure 4 is a block schematic illustrating a satellite unit which comprises an electric mains interface 60, a power unit 61, an electric mains modem 62, a control unit 63, alarm logic 64 which coacts with the control unit 63, a tilt switch 65 and a timer circuit 66. The master unit 2 and each of the satellite units 3 may include voltage circuits which are activated when the voltage supply from the mains voltage system 10 is cut off. The manner in which the embodiment operates will now be described in more detail with reference to Figures 7 and 8. Figure 7 is a block schematic illustrating a control unit 53 included in the master unit 2, and Figure 8 is a block schematic of a control unit 63 included in the satellite 3. The master unit 2 and each of the satellite units 3 used are pre-programmed to be system-related, i.e. they are adapted to a chosen carrier frequency and are assigned a system- related code. The master unit 2 is connected between the host computer VD and the mains voltage supply system 10 in the aforesaid manner. A first satellite unit 3 is connected between a first piece of equipment 11 and the mains voltage supply system 10. The satellite unit 3 requests the master unit 2 to allocate a serial number or an individual number to the satellite unit 3 (and the piece of equipment 11), through the medium of a satellite-associated circuit 81 and with the aid of a system- related code sent to the master unit. The master unit 2 receives the request on a circuit 71, checks the code and chooses a serial number via a circuit 72, and sends the serial number to the satellite unit 3 via a circuit 73, this serial number being received by said unit 3 in a circuit 82 and stored ' in a memory 83. This function is acknowledged, although the acknowledgement is not described here. It will be understood that it is, within the scope of the inventive thought, possible that, upon a new entry of a satellite unit 3, the master unit 2 requests an identi¬ fication of the satellite unit 3, which results a response from the satellite unit that it is new and does not have a serial number, or an individual number, whereafter the master unit 2 allocates a serial number, or an individual number, to the satellite unit 3. The master unit 2 stores the serial number allocated to each satellite unit 3 in a memory 74. The master unit 2 sends a general inquiry to a chosen number (a sub-network) of satellite units via a circuit 75, inquir¬ ing whether or not the setting value has been changed. The chosen number is taken from the memory 74 and placed in a sub-memory 76. When the satellite unit 3 now receives the query in a circuit 84, it detects the current status of an alarm circuit 85. The alarm circuit 85 is constructed to switch from a rest state to an alarm-activating state in the event of an interruption in the mains supply or in response to some other means indicating that the equipment has been taken out of use. When the alarm circuit 85 is in its rest state, an informa¬ tion-carrying signal is sent on the signal route 12, via a circuit 86. This information-carrying signal includes a system-related code, a relevant serial number and the status of the alarm circuit 85, and is received by the master unit 2 in a circuit 77 which response-marks the relevant satellite unit 3 in the sub-memory 76. When all responses have been marked in the sub-memory 76 within a predetermined time period, it is possible that responses have still not been received from a number of initially questioned satellite units. A new general inquiry is then sent to those satellite units that have not replied via the circuit 75, and the above process is repeated. Should one of the satellite units, for instance the satellite unit 3, fail to respond despite repeated inquiries, or should the response received contain information relating to an alarm state, this is evaluated in a circuit 78 which acti¬ vates an alarm indicating unit 79. The master unit 2 is able to determine the satellite unit 3 that has generated an alarm signal via the circuit 78 and by means of the code received, and show all information neces¬ sary to unequivocally identify the satellite unit concerned on a display screen not shown (VDB in Figure 1) via a conductor 78a. The master unit 2 may also include a device (not shown) which automatically calls one or more telephone numbers so as to activate alarm signals. The inventive principle enables such an alarm system to be readily supplemented with an inventory list. By reading the memory 74 and storing therein given satellite units, a memory 20 in the host computer is a able to store all satellite units that have been allocated a serial number together with associated equipment or inventory objects. The memory 20 can change its active memory content by detecting changes (from inactive states) occurring in the receiver circuit 77, wherewith the memory 20 will always contain a current inventory list. The state in the circuit 85 from the master unit 2 can be set via information-carrying signals to "accepted permanent disconnection", "service or temporary disconnection" or "unauthorized" disconnection. The means required in the control units 53 and 63 respective¬ ly to carry out these functions are well known to the person skilled in this art and will not therefore be described in detail here. It will be noted that program memory controlled circuits are used in this connection. The alarm-initiating circuit 87 may be any appropriate circuit, although simple units or more sophisticated units will be chosen in accordance with the type of alarm envis¬ aged. It is important to the present invention that the satellite unit 3 is provided with a simple detector circuit by means of which connection or disconnection of pieces of equipment or objects can be detected. A microswitch 68 is well suited for objects in this regard, and is also suited for use with pieces of equipment. A specially constructed female electrical device 92 is well suited for monitoring pieces of equipment. As shown in Figure 10, the female contact device 92 includes a contact tab 101, 102 for respective conductors 95a, 95a', and with corresponding contact tabs for respective conductors 95b, 95b'. This provides conditions for making an electric circuit when the male electric contact device on the equipment coacts with the female contact device, and to break said current circuit when the male contact device is withdrawn. The time at which this event takes place can be established and registered through the medium of timing circuits, not shown in detail. Figure 1 shows the host computer VD connected to a main host computer HVD. It will be understood that the aforedescribed and illustrated embodiments do not limit the scope of the invention and that modifications can be made within the scope of the inventive concept as defined in the following Claims.

Claims: CLAIMS 1. A control and/or registration system which comprises a host computer which monitors the system either directly or indirectly and a plurality of pieces of equipment or objects which are monitored by the host computer and supplied with voltage from one and the same mains voltage supply system, wherein the monitoring host computer is able to communicate with each of the monitored pieces of equipment either directly or indirectly, wherein each of the monitored pieces of equipment is able to communicate with said host computer either directly or indirectly via information-carrying signals, which are adapted for transmission through the medium of the mains voltage supply system, wherein a master unit belonging to the host computer is connected between the host computer and an electric contact device or outlet belonging to the mains voltage supply system, whereas a satellite unit associated with a monitored piece of equipment or object is connected to an outlet belonging to the mains voltage supply system, wherein the master unit functions to control the status of the electrical connection of each satellite unit by sending information-carrying signals to and receiving information-carrying signals from said satellite unit, and wherein said master unit functions to register all monitored equipment and/or causes the host computer to register all monitored pieces of equipment, characterized in that the master unit functions to assign an identification code to an equipment-monitoring satellite unit and/or to said equipment when connecting-up said satellite unit. 2. A system according to Claim 1, characterized in that when initially connecting-up the satellite unit, said unit asks the master unit for a serial number or like identifica¬ tion. 3. A system according to Claim 3, characterized in that when the electrical connection between the master unit and a satellite unit and/or a monitored piece of equipment is broken, the event is indicated in the master unit. 4. A system according to Claim 3, characterized in that when an electrical connection to a satellite unit and/or to a monitored piece of equipment is broken, the event is indicated on a host computer display screen. 5. A system according to Claim 4, characterized in that said information includes the location of the satellite unit and/or the monitored piece of equipment, optionally supple¬ mented with the time at which the connection was broken. 6. A system according to Claim 3 or Claim 4, characterized by an alarm which is activated when an electrical connection is broken. 7. A system according to Claim 1 or Claim 2, characterized in that the satellite unit includes a communication part which when sending information-carrying signals to the master unit also sends its identification code. 8. A system according to Claim 1, characterized in that the host computer includes an inventory system in which each monitored unit with allocated identity code is inserted together with data relating to the connection or disconnec¬ tion of said unit. 9. A system according to Claim 1 or Claim 8, characterized in that a chosen satellite unit and/or a chosen piece of monitored equipment can be disconnected from the system temporarily or definitely via the host computer. 10. A system according to Claim 1, characterized in that one or more of said host computers is/are connected to a main host computer. 11. A system according to Claim 10, characterized in that all satellite units and/or monitored pieces of equipment that have once been connected but have not been removed from an inventory register are stored in the main host computer. 12. A system according to Claim 1, characterized in that the satellite unit is adapted to change its state via the changed setting of a microswitch. 13. A system according to Claim 1, characterized in that the satellite unit is adapted to change its state in response to the lack of electrical contact of the contact tabs of a female electrical contact device. 14. A system according to Claim 1, characterized in that the master unit is programmed to send to all satellite units a query concerning changes in setting values. 15. A system according to Claim 14, characterized in that the responses received are registerable over a predetermined time period. 16. A system according to Claim 14 or Claim 15, character¬ ized in that when no response is received, the master unit sends a new inquiry to the satellite unit concerned and the response received is registerable over a predetermined time period. 17. A system according to Claim 14 or Claim 16, character- ized in that when no response is received from the satellite unit, an alarm indicating unit is activated.

Inventors: GUSTAFSSON HANS-FREDERIK, HEDSTROEM MATS HOLGER GOERAN, LENASSON KARL TOBIAS, GUSTAFSSON, HANS-FREDERIK, HEDSTROEM, MATS, HOLGER, GOERAN, LENASSON, KARL, TOBIAS
Applicants: GUSTAFSSON HANS FREDERIK, HEDSTROEM MATS HOLGER GOERAN, LENASSON KARL TOBIAS, GUSTAFSSON, HANS-FREDERIK, HEDSTROEM, MATS, HOLGER, GOERAN, LENASSON, KARL, TOBIAS
Application year: 1995
Main classification: G08B25
IPC codes: G08B26, G08B29