DISPLAY SYSTEM HAVING A NUMBER OF LIGHT EMITTERS AND HOLDERS FOR THE LIGHT EMITTERS

Abstract: Display system comprising a number of lamp holders (7) which each have a local control unit (6) and which are suitable for holding and connecting to the local control unit (6) a lamp (8), the local control units (6) of the various lamp holders (7) being connected to a common conductor bundle (3) to which a central control unit (4) and a supply unit (5) are also connected. Each local control unit (6) contains an address. If a local control unit (6) receives a message containing the address of the local control unit (6) from the conductor bundle (3) it responds, depending on any other content of the message, for optionally activating the associated lamp (8), for optionally changing the address and for sending back a message which specifies the conducting state between connections (11) for the lamp (8).

Description: Short title: Display system having a number of light emitters and holders for the light emitters The information relates to a display system comprising a number of light emitters and a central control unit, in which each light emitter is mounted in a holder and each light emitter is connected to the central control unit via connections of the holder and conductors in order to be selectively activated by the central control unit. The invention relates, in particular, to a display system for use in appliances having a large number of light emitters, such as gambling machines and illuminated news trailers. A display system of the above mentioned type is known in practice for use in gambling machines in which the light emitters are incandescent lamps. According to a first known possibility for the connection of the light emitters to the central control unit, first connections of the light emitters are connected to a common supply conductor and second connections of the light emitters are connected to another supply conductor via an individual switching means. Although the central control unit is simple in this case, the large number of connecting points, the extensive wiring and the difficulty in being able to change the wiring are great drawbacks. According to another known possibility for connecting light emitters to the central control unit, each light emitter is connected in series with a diode and each series connection of a light emitter and a diode is connected in the same polarization direction between a row and a column of a matrix and the rows and columns are connected to two supply conductors via individual switching means. Although the number of connecting points is in this case limited, the selective control of the rows and columns makes the central control unit complicated. Furthermore, in the case of use in gambling machines and illuminated news trailers, for example, extensive wiring is nevertheless necessary and this, like the matrix, is difficult to change. Another drawback is that the light emitters can be activated simultaneously only in a limited number of combinations without other light emitters also being unintentionally activated. As a result, in designing the system, account has to be taken of the light output of the various light emitters or groups of light emitters and of the individual activation or time-dependent activation per group of the light emitters. This makes the design troublesome and expensive and presents a drawback to changing the design. In display systems of the above mentioned type, it is known to make use of a holders for light emitters which have blade contacts into which conductors for connection to the central control unit can be pressed, as a result of which the necessary electrical contacts can be effected without other means and operations. The above mentioned drawbacks, however, continue to apply. The object of the invention is to eliminate the drawbacks of the known display system. This object is achieved for the display system mentioned in the introduction in that each holder has a local control unit which is connected to the light emitter of the holder and, via the conductors, to the central control unit, the local control unit has a writable memory in which an address assigned to the local control unit is stored, the local control unit is suitable for detecting a conducting state between the connections for the light emitter, and the central control unit accesses the local control unit by transmitting a message containing the address for optionally activating the light emitter depending on any other content of the message, for optionally changing the address in the memory and for sending back to the central control unit a message about the conducting state between the light-emitter connections. As a result of this, the number of conductors of the system can be limited, for example limited to four, so that the wiring of the system is very simple and the design of the system is easy to change. The common bundle of conductors is, for example, a flat cable which can be pressed into the blade-type contacts of the holders. The light emitters can be set independently of one another to a conducting (active) or nonconducting (inactive) state from the central control unit and can be kept in said state by the associated local control unit. As a result of this, the display system can be designed without account having to be taken of time-distributed activation of the light emitters in various combinations for various display states. In addition, the status of the light emitter can be determined by detecting the conducting state between the connections of the holder for the light emitter, as a result of which programming of the addresses of the various local control units can take place from the central control unit depending on the status. Furthermore, recording of a status fed back to the central control unit simplifies the maintenance of the system. The invention also relates to a holder for a light emitter, comprising holding means, two first electrical contacts and electrical supply terminals connected to the first contacts, the holding means being suitable for securing the light emitter in such a way that the first contacts are in contact with corresponding second contacts of the light emitter, characterized by a control unit which is connected to the first contacts and terminals, the control unit having a writable memory in which an address assigned to the control unit is stored, the control unit being suitable for detecting a conducting state between the first contacts via the second contacts, the control unit being suitable for receiving a message from the outside, and, on receiving a message containing the address of the control unit, the control unit taking action, depending on any other content of the message, for optionally activating the light emitter, for optionally changing the address and for sending back a message about the conducting state. Because the holder has an integrated control unit, it is particularly suitable for use in the display system according to the invention, which then comprises only the central control unit, a supply unit, a number of holders and a simple common wiring. Holders which are in a store can have the same initial address and can be individualized by a separate address after installation in a display system. This simplifies the logistics and the costs thereof. Other advantages and properties of the invention will emerge from the explanation given below with reference to the accompanying drawings, in which: Figure 1 shows an electrical diagram of a display system according to the invention; and Figure 2 shows an electrical diagram of a holder according to the invention. The display system according to the invention shown in Figure 1 comprises a bundle of conductors 3 and, connected to the conductor bundle 3, a central control unit 4, a supply unit 5 and a number of local control units 6. Each local control unit 6 is mounted in a lamp holder 7, in which a lamp 8 is also mounted and which can be connected to the local control unit 6. The lamp holder 7 and the lamp 8 are suitable, in particular, for plugging the lamp 8 removably into the holder 7, a connection taking place between the local control unit 6 and the lamp 8 via contacts 11 of the local control unit 6 and contacts 12 of the lamp 8. The conductor bundle 3 comprises a first supply conductor 14, a second supply conductor 15 for a lower supply voltage and a transmission conductor 16 for the transmission of messages between the central control unit 4 and the local control units 6. The conductors 14, 15, 16 of the bundle 3 are connected, respectively, to terminals 17, 18, 19 (Figure 2) of each local control unit 6. The terminals 17, 18, 19 are, in particular, knife contacts known per se into which the conductors 14, 15, 16 can easily be pressed to make an electrical connection to the local control unit 6. As a result of this, the conductor bundle 3 can easily and rapidly be mounted between all the control units 4, 6 and electrically connected thereto. As shown in Figure 2, the local control unit 6 has a microcontroller 21 having supply terminals P+ and Pwhich are connected to the supply terminals 17, 18 via a voltage regulator 22. A clock 23 is connected to a clock input Cl of the microcontroller 21. One of the contacts 11 of the holder 7 is connected via a measuring resistor 25 to the first supply connection 17 and via a series connection of a low-pass filter 26 and an amplifier 27 to a measurement input Msr of the microcontroller 21. The other contact 11 of the holder 7 is connected via a short-circuit current-limiting resistor 28 to the second supply terminal 18 and via a drive circuit ("driver") to a terminal Drv of the microcontroller 21. The message-transmission terminal 19 is connected via a series circuit of a low-pass filter 31 and an amplifier 32 to a serial data input 11 of the microcontroller 21. A serial data output 0 of the microcontroller 21 is connected via a series circuit of an amplifier 35 and a low-pass filter 36 to the connection 19. A contact 37 which can be electrically contacted from outside the lamp holder 7 is connected via a low-pass filter 38 to a second serial data input I2 of the microcontroller 21. The microcontroller 21 has a memory (not shown) in which an address assigned to the local control unit 6 is stored. If the central control unit 4 transmits, via the conductor bundle 3, a message containing the address of the local control unit 6, the local control unit 6 responds thereto in accordance with any command and further data in the message received but does not otherwise respond. If the message which is received by the local control unit 6 and to which it responds contains an 'activation" command, the driver circuit 29 is controlled by the microcontroller 21 so as to transmit a current from the first supply terminal 17 and via the resistor 25, a lamp 8, which is present, and the circuit 29 so that the lamp 8 will light up. As a result of this, a voltage drop is produced across the resistor 25 so that a voltage at the measurement input Msr of the microcontroller 21 is lower than if the lamp 8 were not present or if the circuit 29 was not set to transmit a current. If the voltage measured is high while the circuit 29 is transmissive, this means that the lamp 8 is not present or is defective. On the other hand, if there is a short circuit between the contacts 11, in particular if the lamp 8 is defective and it forms a short circuit, the measured voltage at the measurement input Msr of the microcontroller 21 deviates from reference voltages for a correctly operating lamp 8 which optionally conducts a current via the circuit 29. If the local control unit 6 has received, via the input I1 of the microcontroller 21, a message which contains the address of the local control unit 6, it performs any command present in the message and sends back a message from the output 0 of the microcontroller 21, the message sent back containing the status or conduction state of the lamp 8 or, more generally, between the contacts 11 of the lamp holder 7. Depending on the status of a lamp holder 7 present in a message received by the central control unit 4, the central control unit 4 records said status and, if necessary, generates an alarm message. If the address of the last message transmitted by the central control unit 4 was an initial address and if the central control unit 4 receives back a message in response thereto, the central control unit 4 transmits a new message which contains a new address and a command which is used by the local control unit 6 having the initial address in order to change the initial address into the new address. The local control unit 6 can be organized permanently or depending on a command received from the central control unit 4 so that, if no current flows between the contacts 11 while the circuit 29 has in fact been rendered transmissive, the local control unit 6 does not send back a message, at least not if the address thereof is the initial address. In conjunction with the manner in which the central control unit 4 responds to a message which is received back in response to a message having an initial address transmitted by the central control unit 4, the display system according to the invention can be particularly easily programmed as a result. That is to say, if all the lamp holders 7 of the display system have been installed, the conductor bundle 3 has been mounted between the supply unit 5 and the control units 4, 6, the addresses of the local control units 6 are the initial address, and no lamps 8 are present in the lamp holders 7, the central control unit 4 can program individual addresses in the various local control units 6 by repeatedly emitting a message containing the initial address and by transmitting a subsequent message containing a new address and an address change command after receiving back a message, that is to say if a lamp holder 7 containing a fitted, correctly operating lamp 8 has responded. The local control units 6 of all the lamp holders 7 can then be consecutively programmed with new addresses or individualized by consecutively fitting lamps 8. Even if the display system is in operation, the central control unit 4 can proceed with the periodical transmission between other messages of a message which contains an initial address. As a result of this, it is possible to replace a lamp holder 7 and to replace the initial address of its local control unit 6 by a new address. Similarly, it is possible to mount additional lamp holders 7. A similar type of message exchange can take place between the central control unit 4 and the local control units 6 if all the lamps 8 have been initially fitted, the addresses of the various local control units 6 are the initial address, and the message transmission conductor 16 is consecutively connected to the local control units 6 of the various lamp holders 7. In the two programming examples explained above, the local control units 6 of the various lamp holders 7 can be rapidly and easily programmed, it only being necessary to be mindful of a certain sequence of fitting lamps 8 or a sequence of connecting the various local control units 6 to the message transmission conductor 16. As an alternative, to program a local control unit 6 of a replaced or added lamp holder 7, a temporary connection can be made between the contact 37 of the local control unit 6 to be programmed and a contact 39 of the central control unit 4 for the purpose of supplying a programming command and a new address for the local control unit 6 to the serial data input I2 of the microcontroller 21 of the local control unit 6 via said temporary connection. A reset device 40, which is, in particular, a switch, is connected to a reset input Res of the microcontroller 21 to enable the microcontroller 21 to be reset to the initial state. Although the invention has been explained for an embodiment having a conductor bundle which comprises three conductors, various alternatives are possible within the scope of the invention. The message exchange can take place, for example, via a separate conductor pair or by modulation of a high-frequency alternating voltage and superimposed on the supply voltage over the conductor pair 14, 15. Furthermore, the lamps 8 can also be replaced, within the scope of the invention, by other types of light emitters, such as light-emitting diodes.

Claims: CLAIMS 1. Display system comprising a number of light emitters (8) and a central control unit (4), in which each light emitter (8) is mounted in a holder (7) and each light emitter (8) is connected to the central control unit (4) via connections (11) of the holder (7) and conductors (14, 15, 16) in order to be selectively activated by the central control unit (4), characterized in that each holder (7) has a local control unit (6) which is connected to the light emitter (8) of the holder (7) and, via the conductors, to the central control unit (4), the local control unit (6) has a writable memory in which an address assigned to the local control unit (6) is stored, the local control unit (6) is suitable for detecting a conducting state between the connections (11) for the light emitter (8), and the central control unit (4) accesses the local control unit (6) by transmitting a message containing the address for optionally activating the light emitter (8) depending on any other content of the message, for optionally changing the address in the memory and for sending back to the central control unit (4) a message about the conducting state between the light-emitter connections. 2. System according to claim 1, characterized in that the conductors comprise supply conductors (14, 15) of which one (14) is connected via a measuring resistor (25) to a connection (ill) for the light emitter (8) and to a measurement input (Msr) of the local control unit (6), the local control unit (6) measuring the voltage at the one connection and the local control unit (6) comparing the measured voltage with one or more reference voltages in order to determine the conducting state between the lightemitter connections. 3. System according to claim 2, characterized in that another supply conductor (15) is connected via a shortcircuit current-limiting resistor (28) to another connection for the light emitter (8) and to a controlled supply port (29) of the local control unit (6). 4. System according to one of the preceding claims, characterized in that the local control unit (6) does no send back a message if the address is an initial and if the conducting state corresponds to the conducting state in the case where no light emitter (8) is mounted between the light-emitter connections. 5. System according to one of the preceding claims; characterized in that the address of a plurality of local control units (6) is initially an identical initial address, the central control unit (4) repebatedly emitting, at least initially, a message containing the initial address and, on receiving back a message which specifies a conducting statefor a mounted light emitter (8) in working order, the central control unit (4) emits a subsequent message containing the initial address, a new address and a command for changing the initial address into the new address. 6. System according to one of the preceding claims; characterized in that the local control unit (6) has an externally contactable programming contact (37) for changing the address of the local control unit (6) via a temporary conductor between the central control unit (4) and the programming contact (37). 7. Holder (7) for a light emitter (8), comprising holding means, two first electrical contacts (11) and electrical supply terminals (17, 18) connected to the first contacts, the holding means being suitable for holding the light emitter (8) in such a way that the first contacts (11) are in contact with corresponding second contacts (12) of the light emitter (8), characterized by a control unit (6) which is connected to the first contacts (11) and terminals (17, 18, 19), the control unit (6) having a writable memory in which an address assigned to the control unit (6) is stored, the control unit (6) being suitable for detecting a conducting state between the first contacts (11) via the second contacts (12), the control unit (6) being suitable for receiving a message from the outside and, on receiving a message containing the address of the control unit (6), the control unit (6) taking action, depending on any other content of the message, for \optionallyJactivating the light emitter (8), forfoDtionallyJ i the address and sending ----, , changing the address and t sending back a message about the conducting state. 8. Holder (7) according to claim 7, characterized in that a first contact (11) is connected to a measurement input (Msr) and, via a resistor (25), to a supply terminal (17). 9. Holder (7) according to claim 7 or 8, characterized in that another of the first contacts (11) is connected to a controlled supply port (29) and, via a resistor (28), to another supply terminal (18). 10. Holder (7) according to one of claims 7 to 9 inclusive, characterized in that the control unit (6) does not send back a message if the address is an initial address and if the conducting state corresponds to the conducting state in the case where no light emitter (8) is mounted between the light-emitter connections. 11. Holder (7) according to one of claims 7 to 10 inclusive, characterized in that the address is initially an identical initial address assigned to a plurality of control units (6). 12. Holder (7) according to one of claims 7 to 11 inclusive, characterized in that an externally contactable programming contact (37) is provided for changing the address of the control unit (6) via a temporary connection between the programming contact (37) and a programming device.

Inventors: DE LEIJER ANTONIUS LAURENTIUS, DE LEIJER, ANTONIUS, LAURENTIUS, GERARDUS, MARIA
Applicants: LEIJER ANTONIUS LAURENTIUS GER, SUZO INTERNATIONAL NL B V, DE LEIJER, ANTONIUS, LAURENTIUS, GERARDUS, MARIA, SUZO INTERNATIONAL (NL) B.V.
Application year: 1997
Main classification: H05B37
IPC codes: G09G3, H05B37