A SET OF DEVICES FOR TRANSFERRING ELECTRIC SIGNALS

Abstract: In a set of devices (1, 4) for transferring electric signals, which each comprises a bus (8, 9) and means (10, 11) for electrical and mechanical connection of this bus to a bus of another of the devices for interconnecting such devices, terminals for outer connection of the device to and signal exchange with electrical arrangements, and a signal adapting module electrically connected to the bus through a connection and to the terminals through a connection, devices according to at least two different designs are provided, which have differently large spaces for arranging terminals and signal adapting components, but the buses of which may be optionally connected to each other and which make it possible to use similar signal adapting modules (13).

Description: A set of devices for transferring electric signals FIELD OF THE INVENTION AND PRIOR ART The present invention relates to a set of devices for transferring electric signals, which each comprises a first unit having a bus and means for electrically and mechani¬ cally interconnecting this bus and a bus of another of the devices for connecting such devices to each other, a second unit having terminals for an external connection of the device to and signal exchange with electrical arrangements, and a signal adapting module electrically connected to the bus through a connection and to the terminals through a connection and thereby electrically connecting the bus and the terminals. Devices of such sets may be of the most different types and they are used for different types of signal transfer, both of numerical and analogous character, said signals arriving to the bus of the device on one hand from for example a central unit and are after a signal adaptation in the signal adapting module emitted through said terminal to different electrical arrangements for their control, and on the other from these arrangements through signal adaptation in the signal adapting module. It may as an example be mentioned that analogous signals arriving to the bus of the device through the terminals after conversion to numerical signals may be measuring signals from any pressure, temperature or flow sensor, wherein an analogous output signal may then be sent to an arrangement for controlling a regulator, for example a valve regulating a flow, or a means regulating the temperature of an oven. Signal arriving to the bus of the device may in the numerical case derive from signal contacts or electrical components similar thereto, while signals from the signal adapting module to the terminals may control for example a motor through a contactor. The bus may also allow communication between different devices connected to each other and a central unit. The devices or the electrical arrangements connected thereto may also receive their power supply through the bus. The space requirement for a device of such a set is strongly dependent upon how many terminals the device has to have, wherein there are devices of two main types, which demand differently much space, for connection to a determined number of electrical arrangements. The first main type is generally called "minimum termination device", and it has substantially the same number of termi¬ nals as the number of electrical arrangements to be con¬ nected thereto, normally one terminal per signal plus one or two terminals for power supply, which the arrangements have in common. Such a device may be compact and demands little space, but it has instead the disadvantage that a number of electrical components have to be arranged outside the device between the latter and the electrical arrangements and an extended arrangement of cables will be necessary, since the electrical arrangements each require two or more terminals. Such electrical components may for example be different types of switching means, circuit breakers, components setting conditions, terminals and so on. It is neither possible to connect more than a few arrangements each requiring two or more terminal connections or connection in¬ terfaces to such a device. Devices according to the second type have more than one terminal for the same number of arrangements as devices according to the first type only have one terminal for, and they may also have said electrical components incorporated in the signal path between the signal adapting module and the terminals, which has the advantage that no such electri¬ cal components has to be arranged outside between the device and the electrical arrangements, which results in a consid¬ erably simplier arrangement of cables. It is instead neces¬ sary to accept that such a device requires more space than devices of the first type, since it has more terminals, often three terminals per arrangement. A disadvantage of sets of the type defined in the introduc¬ tion already known is that they have devices either of the first type or of the second type, which results in locking to a determined connection interface, which may mean that the connection interface for some devices is unnecessarily large and the device in question by that requires more space than should be necessary, or that the connection interface is too small for being able to connect the electrical arrangements desired to connect to a certain device in a de- sired way exactly to the set in question. SUMMARY OF THE INVENTION The object of the present invention is to indicate means for considerably reducing the disadvantage mentioned above. This object is according to the invention obtained by providing a set of the type defined in the introduction, which comprises devices according to at least two different designs, devices belonging to different designs have termi¬ nal units having different sizes of spaces provided thereby for terminals and signal adapting components and bus units having means allowing an optional mechanical connection of the respective bus to a bus of a said device of the same or another design, and devices belonging to different designs have members for establishing a connection to similar signal adapting modules. Thus, it will through the invention be possible to combine devices adapted to exactly the demands of packing density and connection interface required in every special case, and it will be possible to select the connection interface desired for a certain signal adapting module. It will also be possible to combine devices having different connection interfaces to each other while connecting them to the same bus for utilizing the space to an optimum. Thus, an optimum adjustment of the demand of space and of different proper¬ ties may be obtained. However, it is of course well possible to only use devices of one and the same design for connec- tion to each other, should this in a given situation be most suitable. The devices having the larger space have not at all to have a greater number of terminals than those accord¬ ing to the design with the smaller space, but the extra space may instead be used for example for arranging coarser terminals there or more or on the whole signal adapting components there. However, such are not to be present in said space. According to a preferred embodiment of the invention the set comprises devices according to a first design having direct electric connection lines of the terminal unit between the signal adapting module and the terminals thereof and devices according to a second design having electrical components arranged on the terminal unit for processing signals deriv- ing from the signal adapting module on their way to the terminals. Compact devices may by that be combined with advanced devices not requiring any external electrical components and complex arrangements of cables. According to another preferred embodiment of the invention the devices have terminals at a first end thereof, which is opposite to a second end, at which the bus is arranged, and devices according to a design having more terminals than de¬ vices according to another design have a larger extension in the longitudinal direction of the bus, i.e. transversally to a line interconnecting said ends, than the design last mentioned having fewer terminals. Such a design of the devices is advantageous, since devices having a greater number of terminals than other devices will in this way not extend further in the direction away from the bus than these and by that not make it impossible to arrange a cable channel comparatively closely under the row of devices interconnected. According to a preferred further development of the embodi- ment last mentioned devices according to one design having fewer terminals than devices according to another design have members for establishing a connection to said signal adapting module adapted to arrange this module with a longer side thereof extending substantially perpendicularly to the direction of interconnection of devices and the extension of the bus, and devices according to said design having more terminals have members for establishing a connection to the signal adapting module adapted to arrange this module with a longer side thereof extending substantially in the direction of the interconnection of adjacent devices and the extension of the bus. Through such a mutual arrangement of terminals and signal adapting modules of the different designs of devices these may be made very compact for well utilizing the space. According to a further development of the embodiment of the invention last mentioned the width occupied by said termi¬ nals in the direction of the interconnection and the bus ex¬ tension corresponds substantially to the extension of the signal module in the state in which it is applied on the de- vice of the respective design. "Dead" spaces not utilized are by that avoided. Further advantages as well as preferred features of the invention appear from the following description and the other dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS With reference to the appended drawings, below follows a de¬ scription of a preferred embodiment of the invention cited as an example. In the drawings: Figs. 1, 2 and 3 are very schematical views illustrating different possibilities to interconnect devices for trans¬ ferring electric signals of a set of such devices according to a preferred embodiment of the invention, and Fig. 4 illustrates in a perspective view how two devices of different designs of said set are designed and may be interconnected, wherein some parts have been taken away or broken away so as to be able to better illustrate the construction of the devices. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION It is illustrated in Figs. 1-3 how devices of a set of devices for transferring electric signals according to the invention may be connected to each other, said devices each comprising a first unit having a bus and means for electri¬ cal and mechanical interconnection of this bus and a bus of another of the devices for interconnecting such devices to each other, a second unit with terminals for external connection of the device and signal emission to electrical arrangements, and a signal adapting module electrically connected to the bus through a connection and to the termi¬ nals through a connection and by that electrically intercon- necting the bus and the terminals. The combinations illus¬ trated are of course only a few of a great number of possi¬ ble combinations and have the only purpose to illustrate that the set has devices according to two different designs, which primarily differ with respect to the number of termi- nals and which may be optionally connected to each other. More exactly, devices 1 according to a first design have an electronic module 2 indicated through a block comprising a bus unit and a signal adapting module, as well as a terminal unit 3 indicated through another block. The terminal unit of this first design has a small number of terminals, prefer¬ ably a minimum of terminals for connection of a determined number of electrical arrangements to the device. The elec¬ tric module 2 is arranged standing on the shorter edge above the terminal unit for obtaining compactness of the device. The devices are connected to each other through a bus 8, 9. A set according to the invention has also devices 4 accord¬ ing to a second design, which differs from the first one by the fact that the terminal units 5 have a greater number of terminals, so that the terminal units require larger space and have been given a larger extension primarily in the direction of interconnection of adjacent devices, which has motivated an arrangement of the electric module 6 belonging thereto with the extension of the longest side thereof substantially in said direction. The very construction of the devices according to said two designs will now be explained more in detail while making reference to Fig. 4. An interconnection of devices for transferring electric signals according to the simplified illustration of Fig. 3 is illustrated in this figure. Some parts of some devices have been removed or broken away for better illustrating the construction of the devices. Each device has a bus unit 7 with a bus connection 8 and a bus connection 9 with means 10, 11 for electrical and mechanical interconnection of the respective bus and a bus of another of the devices for connecting such devices to each other. The bus 8, 9 is arranged on a printed circuit card not visible and included in the bus unit 7. The bus unit has also members, which are indicated at 12, for establishing a connection between the bus and the inlet of a signal adapt¬ ing module 13, which by the men skilled in the art is called I/O module (input/output module). The signal adapting module 13 is adapted to carry out an adaptation of signals arriving thereto or leaving it between their representation on the bus and at the terminals. It has a bi-directional connection interface towards the bus as well as the terminals mentioned hereinafter. The devices have also a terminal unit 14 with terminals or connection blocks 15 for connecting the device to electrical arrangements. The terminal unit has also members 16 for establishing a connection to a signal connec¬ tion of a signal adapting module 13. The terminals 15 and the connection member 16 are arranged on a printed circuit card 17 in common, which is indicated through openings in a carrier for the terminal unit. Conduction paths of the printed circuit card connect the member 16 and the terminals 15 electrically to each other. The devices have on the rear side a recess 18 for securing to a conventional mounting rail. The members 16 of the devices in connection with one connec¬ tion of the signal adapting module may be directly connected to corresponding terminals 15 through conduction paths arranged on the printed circuit card or other electrical components, which have to be connected between the signal adapting module and the electrical arrangements intended to be connected to the terminals of the device and are arranged on the printed circuit card 17 in the path of the signals between the signal adapting module and the terminals. This necessitates then a requirement of larger printed circuit card and a larger terminal unit. Devices 1 according to the first design have for a deter¬ mined number of arrangements connectable thereto one connec¬ tion interface, i.e. the terminal per arrangement, while de¬ vices 4 according to the second design offer more than one connection interface per arrangement at said number thereof, which makes the space demand, i.e. the space demand for the terminals thereof, larger. Devices of different designs have been designed so that they may be connected to each other while establishing a continu¬ ous bus extending therethrough and while providing the possibility to use an identical signal adapting module 13 for devices having different designs, so that for a signal adapting module the connection interface considered to be most appropriate in a given use may be chosen so as to satisfy the need of number of connection interfaces and space in the best possible way. A device 1 with a minimum amount of terminals has typically one terminal per arrangement to be connected thereto as well as one or two terminals in common for the arrangements for power supply thereof, which may mean 16 + 1 or 16 + 2 necessary terminals for a 16-channel device, while a device 4 having an advanced terminal unit may typically have several terminals for each arrangement to be connected thereto, which may mean 3 x 16 terminals. These three may be intended for + and - for supply and for signal. The invention is of course not in any way restricted to the preferred embodiment described above, but several possibili¬ ties to modifications thereof would be apparent to a man with skill in the art without departing from the basic idea of the invention. It is for instance within the scope of the invention to provide a set of devices according to more than two differ¬ ent designs. "Electrically connected" and "electrically connected" in the claims and in the description has not be interpreted as a requirement to have a direct electrical connection estab¬ lished, but the parts in question may be galvanically separated from each other. Thus, such a connection means that electric signals may be transported between said parts.

Claims: Claims 1. A set of devices (1, 4) for transferring electric sig¬ nals, which each comprises a first unit (7) having a bus (8, 9) and means (10, 11) for electrically and mechanically interconnecting this bus and a bus of another of the devices for connecting such devices to each other, a second unit (14) having terminals (15) for an external connection of the device to and signal exchange with electrical arrangements, and a signal adapting module (13) electrically connected to the bus through a connection and to the terminals through a connection and thereby electrically connecting the bus and the terminals, characterized in that it comprises devices (1, 4) according to at least two different designs, that de- vices belonging to different designs have terminal units having different sizes of spaces provided thereby for terminals and signal adapting components and bus units having means (10, 11) allowing an optional mechanical connection of the respective bus to a bus of a said device of the same or another design, and that devices belonging to different designs have members (12, 16) for establishing a connection to similar signal adapting modules. 2. A set according to claim 1, characterized in that it com- prises devices ( 1 ) according to a first design having direct electric connection lines of the terminal unit ( 14) between the signal adapting module (13) and the terminals thereof and devices (4) according to a second design having electri¬ cal components arranged on the terminal unit for processing signals deriving from the signal adapting module on their way to the terminals. 3. A set according to claim 1 or 2, characterized in that the devices (4) according to one of the designs have a greater number of terminals (15) than devices (1) according to the other design. 4. A set according to claim 2, characterized in that the de¬ vices (4) according to the second design have a greater number of terminals (15) than devices (1) according to the first design. 5. A set according to any of claims 2-4, characterized in that the terminal units (14) of the devices have a printed circuit card (17) with conducting paths for electric connec- tion of the signal adapting module (13) to the terminals (15), and that the electrical components of the devices (4) according to the second design are arranged on the printed circuit card. 6. A set according to any of claims 1-5, characterized in that the devices (4) according to the design having more terminals than devices (1) according to another design extend over an area having a size exceeding the size of the extension area of the devices according to the design last mentioned corresponding to the additional space required by the additional number of terminals or other electrical components. 7. A set according to any of claims 1-6, characterized in that the devices have terminals (15) at a first end thereof, which is opposite to a second end, at which the bus (8, 9) is arranged, and that devices according to a design having more terminals than devices according to another design have a larger extension in the longitudinal direction of the bus, i.e. transversally to a line interconnecting said ends, than the design last mentioned having fewer terminals. 8. A set according to claim 7, characterized in that devices (1) according to a design having fewer terminals than devices (4) according to another design have members (12, 16) for establishing a connection to said signal adapting module (13) adapted to arrange this module with a longer side thereof extending substantially perpendicularly to the direction of interconnection of devices and the extension of the bus, and that devices (4) according to said design having more terminals have members for establishing a connection to the signal adapting module (13) adapted to ar¬ range this module with a longer side thereof extending substantially in the direction of the interconnection of ad¬ jacent devices and the extension of the bus. 9. A set according to claim 8, characterized in that the width occupied by said terminals (15) in the direction of said interconnection and the bus extension substantially corresponds to the extension of the signal adapting module (13) in the state in which this is applied on the device (1, 4) of the respective design. 10. A set according to any of claims 1-9, characterized in that it has αevices (1, 4) of two different designs. 11. A set according to any of claims 1-10, characterized in that it has devices according to the design having at least twice as many terminals as devices according to another design. 12. A set according to any of claims 1-11, characterized in that the devices (1, 4) thereof are adapted for connection to a determined, equal number of electrical arrangements through the terminals thereof, and that it has devices (1) according to one design having terminals adapted for single wire connection to said determined number of arrangements and devices (4) of another design adapted for n-wire connec¬ tions to said determined number of arrangements, n being an integer, which is 2 or greater than 2. 13. A set according to claim 12, characterized in that n ±≤ 3.

Inventors: STRANDBERG LARS, STRANDBERG, LARS
Applicants: ASEA BROWN BOVERI, STRANDBERG LARS, ASEA BROWN BOVERI AB, STRANDBERG, LARS
Application year: 1997
Main classification: H01R9
IPC codes: H01R9, H01R31