CONTROL SYSTEM

Abstract: The invention relates to a control system comprising a motherboard (1) having at least two auxiliary card connectors (2A, 2B, 2C) and a control bus (6) on which control addresses and control data are transferred. Auxiliary cards (3A, 3B, 3C) are connected to the auxiliary card connectors of the motherboard, the auxiliary cards being essentially identical but having different control addresses for selective controlling through the control bus (6). In the present invention the control addresses of the auxiliary cards are card location-specific and provided (8A, 8B, 8C) on the motherboard by wiring or switches or in some other corresponding manner. When an auxiliary card is inserted in an auxiliary card connector of the motherboard, the auxiliary card always obtains the correct address from the motherboard through the connector.

Description: Control system Field of the Invention The invention relates to a control system com- prising a motherboard having at least two auxiliary card connectors and a control bus on which control addresses and control data are transferred, and at least one aux¬ iliary card connected to one of the auxiliary card con¬ nectors, the auxiliary card having a control address for selective controlling through the control bus. Background of the Invention In various kinds of control systems a master unit typically controls slave units via a common control bus. Each control unit connected to the bus has a con¬ trol address (identifier) for identifying the commands addressed to it from among the commands given on the common bus. In a module or circuit card implementing the slave unit, the control address is made by a fixed wiring, or the address can be set e.g. by switches. Alternatively, every module or card may receive a dedic¬ ated control signal from the master unit. A drawback in this known solution is that with otherwise identical cards, it is necessary to know the address set or to be set to each card. The modules and cards used are thus different in respect of production, selling, installa¬ tion or maintenance, and their installation requires specific settings or tuning. Disclosure of the Invention The object of the invention is to provide a control system in which the above problems are elimin¬ ated. This is achieved with a control system of the "type described in the first paragraph, the system according to the invention being characterised in that the control address is card location-specific and the control address of the auxiliary card is not determined until the auxiliary card is connected to an auxiliary card connector, and that the motherboard comprises means connected to the auxiliary card connectors for providing control address data of the card location through the auxiliary card connector to the auxiliary card. In the present invention the control addresses of the auxiliary cards are card connector-specific and they are set by wiring, by switches or in some other corresponding manner on the motherboard. When the auxil¬ iary card is connected to the auxiliary card connector of the motherboard, the auxiliary card always obtains the correct address from the motherboard through the connector. On account of the invention, the user need not set the required address data separately, which facilitates assembling, testing, installation and main¬ tenance. In addition, the auxiliary cards are identical; they do not have any differences, not even in control addresses, in respect of production, selling, installa¬ tion or maintenance. Brief Description of the Drawings In the following the invention will be described by means of preferred embodiments, with refer¬ ence to the attached drawing, wherein Fig. 1 shows a block diagram of a control system implemented in accordance with the invention for controlling combiner filters at a base station, Fig.2 illustrates inputting of control address data from the motherboard through a connector to an auxiliary card. Preferred Embodiments of the Invention In principle, the present invention can be applied in any control equipment in which several ident¬ ical auxiliary cards with different control addresses are to be connected to a motherboard or bus card com- prising a common control bus. However, in the following the invention will be exemplified by a control system which controls the combiner filters at a base station of a radio system. At the base station, several radio transmitters are connected to one antenna or antenna line so that each radio transmitter is connected through its own bandpass filter having a centre frequency tuned to the transmission frequency of the radio transmitter. Bandpass filters of this kind are called combiner filters. A combiner filter supplies a transmission signal from the associated radio transmitter to the antenna with as low power losses as possible and, on the other hand, prevents - as effectively as possible - a leakage of transmission signals generated by other radio transmitters at different frequencies into the associ- ated radio transmitter from the direction of the antenna. Combiner bandpass filters may be fixedly tuned to predetermined transmission frequencies or, alternat¬ ively, a combiner filter may be tuneable to a desired frequency. In the latter case an adaptive control is usually involved with the combiner filter so as to min¬ imize the losses in the filter. Fig. 1 shows a control system for combiner filters. An elementary unit of the control system is a motherboard 1, which comprises a common control bus 6. The motherboard 1 is connected by a card connector 9 to a master control card 5, which outputs control addresses and control data to the bus 6. The motherboard 1 also comprises at least two auxiliary card connectors 2A, 2B and 2C. An auxiliary card, in this embodiment a stepper motor control card 3A, 3B and 3C, is inserted to each of the connectors 2A, 2B and 2C, respectively. Further, the motherboard 1 is connected, either directly by a card connector or by cables, with a group of combiner filter units 4. Each of the combiner filter units com- prises a stepper motor 42, which controls the centre frequency of the combiner filter mechanically. The combiner filter card 4 also comprises control logic 41, which receives control signals 41 from the corresponding stepper motor control card 3A, 3B or 3C through a corre- sponding motor control bus M-R 1-10. The combiner card 4 also comprises at least one guard switch unit 45, which indicates when the motor 42 is in an extreme posi¬ tion, for example in zero position. The state of the guard switch 45 is indicated by a guard switch state line 44 to the corresponding stepper motor control card 3A, 3B or 3C. The state line 44 is part of each motor control bus M-R 1-10. In accordance with the invention, the stepper motor control cards 3A, 3B and 3C are identical and they can be freely arranged in the card locations formed by card connectors 2A, 2B and 2C. For each card connector 2A, 2B and 2C, a dedicated card location-specific con¬ trol address encoding circuitry 8A, 8B and 8C is pro¬ vided on the motherboard 1 e.g. by fixed wiring, by adjustable code switches, or by some other corresponding solution. The encoded control address data are connected to predetermined signal lines in the card connectors 2A, 2B and 2C. For example, when the control card 3A is inserted in the connector 2A, the control address code 8A on the motherboard 1 will be connected through the connector 2A to lines 10 within the control card 3A, from where it can be read by a control unit 31 of the control card 3A. In the embodiment of Fig. 2, a 2-bit control address "01" wired to the motherboard 1 can be read by the control card 3A through the connector 2A. The control address indicates to the control card 3A which commands on the bus 6 are to be responded to in this card location and which combiner units 4 are con¬ trolled. Correspondingly, the control card 3B receives a 2-bit control address "11" wired to the motherboard through the connector 2B. The control card 3A also comprises switching means 32 for switching guard switch state data 44 from the combiner card 4 to one or more common guard switch state lines 7 on the motherboard 1 when the control address of the corresponding card location is on the control bus 6. The control unit 1 monitors the bus 6 and controls the switching unit 32 by a control signal 33. The encoding circuitry 8A, 8B and 8C on the motherboard 1 may also comprise other fixed card loca¬ tion-specific control information, such as the frequency data of the combiner unit to be controlled. The Figs, and their description are to be understood only as illustrating the present invention. In its details the control system according to the application may vary within the scope of the attached claims.

Claims: Claims 1. A control system, comprising a motherboard (1) having at least two auxiliary card connectors (2A, 2B, 2C) and a control bus (6) on which control addresses and control data are transfer¬ red, and at least one auxiliary card (3A, 3B, 3C) con¬ nected to one of the auxiliary card connectors, the auxiliary card having a control address for selective controlling through the control bus (6), c h a r a c ¬ t e r i s e d in that the control address is card location-specific and the control address of the auxiliary card (3A, 3B, 3C) is not determined until the auxiliary card is con¬ nected to an auxiliary card connector (2A, 2B, 2C), and that the motherboard (1) comprises means (8A, 8B, 8C) connected to the auxiliary card connectors for providing control address data of the card location through the auxiliary card connector to the auxiliary card. 2. A control system according to claim 1, c h a r a c t e r i s e d in that said means (8A, 8B, 8C) for providing address data comprise a wired encoding circuitry on the motherboard (1). 3. A control system according to claim 1, c h a r a c t e r i s e d in that said means (8A, 8B, 8C) for providing address data comprise encoding switches on the motherboard. 4. A control system according to claim 1, 2 or 3, c h a r a c t e r i s e d in that said means (8A, 8B, 8C) for providing address data further provide other fixed control information about the card location through the card connector to the auxiliary card. 5. A control system according to claim 1 for controlling combiner filters at a base station, c h a r a c t e r i s e d in that the system comprises combiner filter units (4), each of which comprises a stepper motor (42), means (41) for controlling the stepper motor, and a guard switch unit (45), and that each of the cards (3A, 3B, 3C) is a stepper motor con¬ trol card controlling at least one of the combiner filter units. 6. A control system according to claim 5, c h a r a c t e r i s e d in that stepper motor control lines and a guard switch state line (M-R 1-10, 45, 44) are provided between the combiner filter unit (4) and the corresponding stepper motor control card (3A, 3B, 3C). 7. A control system according to claim 6, c h a r a c t e r i s e d in that the system comprises a master controller (5), which is connected to the control bus (6) of the motherboard (1) for selective controlling of said at least two auxiliary cards (3A, 3B, 3C), and that between the master controller and the stepper motor control cards there is at least one common guard switch state line (7), and that the stepper motor control card comprises means (32) for supplying the guard switch state data received from the combiner filter card to said common switch state line (7) when the control address of the corresponding card location appears on the control bus. 8. A control system according to any one of claims 5 to 7, c h a r a c t e r i s e d in that said means for providing a control address provide data about the frequency of the combiner filter unit through the auxiliary card connector to the stepper motor control card.

Inventors: VASANOJA JUHA, VASANOJA, JUHA
Applicants: NOKIA TELECOMMUNICATIONS OY, VASANOJA JUHA, VASANOJA, JUHA
Application year: 1993
Main classification: G06F12
IPC codes: G06F12, G06F13