Abstract:
The invention relates to a module for a measuring device and to a measuring device. The inventive module for a measuring device is provided with a plug-in contact element for the electrical contact of the plug-and-socket plate of the measuring device which is used for data transfer. Said module for the measuring device comprises a main circuit card arranged in the first circuit card space. Said first circuit card space is formed by at least one first element of the body which encompasses the circuit card in a closed manner on the level of the external periphery thereof.

Description:
BACKGROUND  
       [0001]     The invention relates to plug-in measuring-device modules for insertion into a measuring device and a measuring device with measuring-device modules, which can be plugged into a measuring device housing.  
       SUMMARY  
       [0002]     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.  
         [0003]     Building up measuring devices from several measuring-device modules which can be plugged into a housing is already known, for example, from DE 39 33 647 A1. In this document, the measuring device is formed from a housing, into which several plug-in components are inserted. The plug-in components are jointly connected to a plug-and-socket panel by means of which an electrical connection of the plug-in components is achieved. The individual plug-in components are combined in their function to form a complete measuring device.  
         [0004]     The housing is designed to be inserted into a 19-inch rack, without the need to remove the plug-in component groups from the housing in order to fit them into a 19-inch rack of this kind. The plug-in component groups are inserted into the measuring device from the front. Accordingly, when inserting the housing into a 19-inch rack, all of the connections of the plug-in component groups are therefore accessible exclusively from the front. However, if the measuring device is to be used as a table-top device, it can be fitted with an information-output device arranged as a functional unit at the rear of the measuring device. The information-output device extends over the entire width of the measuring device. To operate the measuring device, it must be rotated so that the information-output device is facing towards the operator. The connections, which are arranged on the individual plug-in component groups, are at the same time turned away from the operator, so that a connection, for example, of a measuring line, is possible only at the side facing away from the operator.  
         [0005]     Such measuring-device modules have the disadvantage that a module, which provides the appropriate structural space for the necessary electronic components, must be specially constructed for each module type. In the case of plug-in component groups with a small space requirement, the use of standardized parts is therefore only possible if a corresponding empty space is acceptable.  
         [0006]     With the measuring device described, it is disadvantageous that a connection of a measuring line is not possible at the side facing the operator.  
         [0007]     A further disadvantage is that a mobile use of the measuring device is only possible under limited conditions, because a protective device against vibrations is not provided for the individual plug-in component groups. The reliability of this measuring device is considerably reduced because of the absence of such a protective device against vibrations, which may occur, for example, when the device is put down at a measuring station.  
         [0008]     A further disadvantage is that, with the device proposed, the individual plug-in component groups form a complete functional unit only in combination with one another. It is therefore necessary to calibrate the measuring device in its entirety including all of the co-operating plug-in component groups. Replacement of an individual plug-in component group is not possible without re-calibrating the measuring device.  
         [0009]     The object of the present invention is to create a measuring-device module, which satisfies different structural space requirements with an extensive use of standardized parts, and to create a measuring device with plug-in measuring-device modules, which allows convenient operation by an operator from the side with the display device.  
         [0010]     This object is achieved by the measuring-device modules as defined according to the invention in the claims.  
         [0011]     Each individual measuring-device module provides a first printed-circuit-board space and a second printed-circuit-board space. The use of such mutually separate spaces allows the possibility of arranging those components, which are sensitive particularly with regard to their high-frequency behavior, for example, in the first printed-circuit-board space, and of protecting this space from electromagnetic radiation with special protective measures. Such protective measures can also be arranged on the printed-circuit board itself, for example, by means of a metallic covering of the components. This allows an open design of the measuring-device module, which leads to a better flow of cooling air.  
         [0012]     Moreover, it is advantageous if the measuring-device module is built up from at least one frame element, of which the external periphery surrounds the printed-circuit board arranged inside it in an essentially enclosed manner. The use of frame elements allows the achievement of a variable system with a high degree of symmetry. This means that production costs can be kept to a minimum in view of the small number of different parts to be manufactured.  
         [0013]     Advantageous further developments of the measuring device and the measuring-device modules according to the invention are possible with reference to the measures defined in the dependent claims.  
         [0014]     In particular, it is advantageous, if, in addition to the connections arranged at the front of the device, further connections, which are arranged on the individual measuring-device modules, are provided at the rear of the device as input or output connections. As a result, those connections, which must frequently be linked to different lines by the operator, can be arranged at the front of the measuring device, while other connections, which are used less frequently, can be arranged at the rear. This leaves a large area at the front of the measuring device, which is available either for the arrangement of operating elements or for a large display.  
         [0015]     Moreover, it is advantageous to fit the measuring-device modules into the measuring device by means of a guide device, wherein the guide device has at least one resiliently deformable guide element, which is capable of reducing the hardness of any impact acting on the measuring-device module as a result of a vibration. The reliability and operating life of the measuring device is considerably improved because of the correspondingly reduced acceleration acting on all of the components contained in the respective measuring-device module.  
         [0016]     In this context, the grid dimension of the guide devices is advantageously selected so that, between each adjacent measuring-device module, in the region of the first printed-circuit-board spaces, a slight gap is formed through which an air flow is guided in order to cool the measuring-device modules. To prevent a tilting or rotary movement of the inserted measuring-device modules, the guide elements are preferably formed from a number of resilient tongues arranged in a row.  
         [0017]     The plug-and-socket panel is mounted in a floating manner within the measuring-device housing in order to prevent the measuring-device modules from damaging the connection sockets formed on the plug-and-socket panel as they move during a vibration and to balance tolerances. In this context, the mounting is preferably designed so that a displacement of the plug-and-socket panel can only take place by overcoming a certain frictional force, so that a vibration of the measuring device as a whole leads to a considerable damping of the movement of the individual measuring-device modules.  
         [0018]     By particular preference, the measuring-device modules are designed as, per se, enclosed functional units. This means that each measuring-device module provides the full functional scope of a measuring device. In this context, the connections, by means of which a measuring-device module is connected, are used on the one hand, to connect a device or a component group to be measured and, on the other hand, to connect the measuring-device module to a bus system, which is provided according to one preferred embodiment of the plug-and-socket panel. The data produced by a measuring-device module are supplied via this bus system to other measuring-device modules or to external computer systems for further processing. In addition to transferring parameter sets for the implementation of a measurement to the relevant measuring-device modules, the bus system is also used for supplying electrical energy to the measuring-device modules. For this purpose, a power pack designed as a plug-in module is provided, which makes use of the grid dimension of the measuring-device modules used, but occupies several grid units, and which is also connected via a plug connection to the plug-and-socket panel.  
         [0019]     Furthermore, it is advantageous that each base element of a measuring-device module can be connected to another base element and that each second printed-circuit-board space of the two connected base elements forms a common additional printed-circuit-board space. In this case, each first printed-circuit-board space is a separate, enclosed space for each base element, which has only one or more locally limited openings for the passage of parts of a main printed-circuit board. In each first printed-circuit-board space, one main printed-circuit board is accommodated respectively, the two main printed-circuit boards preferably being connected via an additional printed-circuit board arranged in the additional printed-circuit-board space. Accordingly, the two base elements, connected via an additional printed-circuit board in the additional printed-circuit-board space, jointly form a measuring-device module, which is plugged into the measuring device. The two main printed-circuit boards can also be connected by a cable or may have a direct plug connection in the additional printed-circuit-board space.  
         [0020]     Moreover, the second printed-circuit-board space can be extended to form an additional printed-circuit-board space by connecting one base element to a frame element instead of the second base element; as a result of the additional printed-circuit-board space, an enlarged region is provided in which the main printed-circuit board of the measuring-device module can be connected.  
         [0021]     Opposite to a connection of this kind provided in the region of the second printed-circuit-board space, a connection carrier, on which an additional electrical connection is arranged, is advantageously provided on the base element. While the connections provided in the region of the second printed-circuit-board space are orientated towards the rear of the device, the additional electrical connection is positioned, by means of the connection carrier, so far in the direction of the front of the measuring device that, when the measuring-device module is inserted, it can be inserted through the recess in the front of the device and can be operated from the front.  
         [0022]     With the base element made from two frame elements, which can be connected together to form a base frame, it is particularly advantageous if the frame elements are provided with centering elements on which the main printed-circuit board is centered within the base frame. The printed-circuit board is fixed between the two frame elements during assembly of the second frame element.  
         [0023]     The connection between a measuring-device module and the plug-and-socket panel preferably takes place by means of a plug-in contact element, which is designed as a part of the main printed-circuit board and is guided from the first printed-circuit-board space through an appropriate recess in the base frame. For this purpose, the frame elements, which are preferably manufactured as cast parts, are milled, only one milled recess being preferably formed in each frame element when the base frame has been assembled, so that a groove provided to receive an HF seal does not need to be penetrated.  
         [0024]     Frames which are open at both sides of the surface of the main printed-circuit board are preferably used as the frame elements. Cover plates are then fitted to the base frame, which consists of two frame elements of this kind, to form a closed base element. To improve cooling, the cover plates can have perforations through which the cooling air can flow into the measuring-device module. To attach the cover plates to the base frame, clip elements are provided, which are pushed over the cover plates from the external periphery of the base frame after placing the cover plates onto the base frame. Accordingly, the base frame and the cover plates are combined to form a base element by the attachment of the clip elements, wherein the clip elements provide locking projections, which engage with corresponding indentations provided in the cover plates in the form of beading strips. This prevents an accidental release of the clip elements, which are under spring tension.  
         [0025]     Furthermore, the clip elements provide a surface, which is arranged in the region of the external periphery of the base frame after fitting the clip elements, and is formed on the at least one guide element. This guide element co-operates with a corresponding guide element formed on the measuring device to form a guide device. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0026]     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0027]      FIG. 1  shows a schematic presentation of a view of the front of the measuring device according to the invention;  
         [0028]      FIG. 2  shows a perspective presentation of a receiving device of the measuring device;  
         [0029]      FIG. 3  shows a perspective presentation of the receiving device with housing components removed;  
         [0030]      FIG. 4  shows a perspective presentation of the receiving device with the measuring-device modules removed;  
         [0031]      FIG. 5  shows a perspective presentation of the receiving device with the blank elements removed;  
         [0032]      FIG. 6  shows a schematic presentation of the structure of a first measuring-device module according to the invention;  
         [0033]      FIG. 7  shows a schematic presentation of the structure of a second measuring-device module according to the invention;  
         [0034]      FIG. 8  shows a schematic presentation of the structure of a first measuring-device module according to the invention consisting of two base elements;  
         [0035]      FIG. 9  shows a schematic presentation of the structure of a second measuring-device module according to the invention consisting of two base elements;  
         [0036]      FIG. 10  shows a schematic presentation of the structure of a first measuring-device module according to the invention with spacing elements;  
         [0037]      FIG. 11  shows a schematic presentation of a third measuring-device module according to the invention consisting of two base elements;  
         [0038]      FIG. 12  shows a schematic presentation of a third measuring-device module according to the invention consisting of two base elements shown from a second perspective;  
         [0039]      FIG. 13  shows a schematic presentation of a fourth measuring-device module according to the invention;  
         [0040]      FIG. 14  shows a schematic presentation of the structure of a fifth measuring-device module according to the invention with a frame body; and  
         [0041]      FIG. 15  shows a schematic presentation of the structure of a fifth measuring-device module according to the invention with a frame body from a second perspective. 
     
    
     DETAILED DESCRIPTION  
       [0042]     An exemplary embodiment of a measuring device according to the invention is illustrated in  FIG. 1 . The measuring device  1  according to the invention comprises a measuring-device housing, at the front of which an information-output device  9  is arranged. A display device  3  is integrated in the information-output device  9 . Furthermore, to operate the measuring device  1 , several operating elements  4 , which can be used to adjust various parameters for the implementation of a measurement or to call up different functions, are arranged in the information-output device  9  in the area on the front of the measuring device not required for the display device  3 . A recess  5 , through which an electrical connection  6  is accessible, is also provided at the front of the measuring device  1 .  
         [0043]     As will be described in greater detail below, the electrical connection  6  is arranged on a measuring-device module, which can be plugged into the measuring device  1  and, after assembly of the measuring-device module, projects through the recess  5  at the front of the measuring device  1 . In the exemplary embodiment of the measuring device  1  according to the invention, the recess  5  is large enough to create an access to a second electrical connection, which can be provided for a further measuring-device module plugged into the device. In the exemplary embodiment presented, the corresponding opening in the front panel of the measuring device  1  can be closed with a blank cover  7 .  
         [0044]     Furthermore, a handle  8 , which can be fixed to the lateral surfaces of the measuring device  1  via a clip device in a rail, is arranged on the measuring device housing  2 . The handle  8  can be fixed via the clip device in almost any position required, so that it also acts as a support for the measuring device  1 , by means of which the inclination of the measuring device can be adjusted.  
         [0045]      FIG. 2  shows the interior of the measuring device  1 . The information-output device  9  arranged at the front of the measuring-device housing has been removed to allow a better view. Within the measuring-device housing  2 , a receiving device  10  is arranged, at the front  10   a  of which the information-output device  9  is attached. In this context, the information-output device  9  is screwed to an operating-panel carrier  16  and is fixed together with the latter to the receiving device  10 . By means of the operating-panel carrier  16 , the information-output device  9  is arranged at a distance from a plug-and-socket panel  11 , which, in the exemplary embodiment shown, is arranged in the receiving device  10  parallel to the front of the measuring device  1 .  
         [0046]     The height h of the plug-and-socket panel  11  is significantly smaller than the overall structural height H of the receiving device  10 . The plug-and-socket panel  11  is arranged in an upper region of the receiving device  10 . By way of extension of the plug-and-socket panel  11 , an air-guide plate  18  is arranged toward the base  17  of the receiving device  10 . Together with the plug-and-socket panel  11 , the air-guide plate  18  separates the entire structural volume of the measuring device housing  2  into a front and a rear region.  
         [0047]     A fan  19  is arranged in a lower region of the operating-panel carrier  16 , which pumps ambient air via a cooling-air inlet  28 , which is provided in a lateral wall of the measuring device  1 , into a cooling-air shaft  21  to cool the electronic components of the measuring device  1 . The cooling-air shaft  21  is limited at the lower side of the housing by a base plate  22  of the operating-panel carrier  16  and at the upper side by an intermediate plate  23 . The intermediate plate  23  is disposed at the height of the transition between the plug-and-socket panel  11  and the air-guide plate  18 .  
         [0048]     The air-guide plate  18  provides a plurality of openings  24 , by means of which the cooling-air shaft  21  is connected to a module region  25  in the rear portion of the receiving device  10 . The air drawn by means of the fan  19  from the environment around the measuring device  1  accumulates in the cooling-air shaft  21 . The pressure is balanced via the openings  24  in the direction of the module region  25 , so that the module region  25  is regularly supplied with fresh cooling air. The electronic components of the measuring-device modules arranged in the module region  25  are cooled by the flow of cooling air. To achieve an air flow for cooling the measuring-device module not only in the lower region of the measuring device  1 , the air-guide plate  18  is designed in an angled manner, thereby forming a vertical portion  18   a  and a horizontal portion  18   b . The cooling air is then deflected over the horizontal portion  18   b  from the cooling-air shaft  21  into the region of the plug-and-socket panel  11 .  
         [0049]     The cooling-air shaft is limited in the direction towards one side wall  30  of the operating-panel carrier  16  by a perforated plate  31 , in order to provide an accessible electrical connection, at least for some of the measuring-device modules fitted, which is also accessible from the information-output device  9 . Between the side wall  30  and the perforated plate  31 , the air-guide plate  18  is cut away appropriately creating a through opening  32 , through which, as already explained, the electrical connections of the measuring-device module accessible from the front of the measuring device can be plugged.  
         [0050]     A guide device  15  is formed on the base  17  of the receiving device  10  for each of the plug-in measuring-device modules, into which an individual measuring-device module can be introduced from the open, rear side  26  of the receiving device  10 . This guide device  15  comprises a groove  27 , which achieves the lateral guiding of a measuring-device module. Furthermore, the guide device  15  comprises several resilient tongues  14 , which are arranged in the groove  27 . The resilient tongues  14  hold the inserted measuring-device module at a defined distance from the base  17  of the receiving device  10 . If a force acts upon the inserted measuring-device module, for example, when the measuring device is placed on a table, then the resilient tongues  14  are subjected to resilient deformation and the impact on the measuring-device module is therefore reduced. The guide components  15  of the receiving device co-operate with guide elements, which are arranged on the measuring-device modules and will be described below, in guiding the measuring-device modules.  
         [0051]     For the exchange of data, each inserted measuring-device module is connected to a plug-and-socket panel  11  via one plug-in connection, several plug sockets  12   a  to  12   e  being provided on the plug-and-socket panel  11  for this purpose. In addition to this number of plug sockets  12   a  to  12   e , further plug sockets  27   a  to  27   b  can also be provided on the plug-and-socket panel  11 , which are used, for example, for connecting a computer module. The plug sockets  12   a  to  12   e  and the further plug sockets  27   a ,  27   b  are components of a bus system which is formed on the plug-and-socket panel  11 . This bus system is controlled via a computer module, which is also plugged into the receiving device  10 . The distance between the plug sockets is determined by the grid dimension, according to which the guide devices are designed; by way of deviation from this, the plug sockets  12   a  and  12   b  have a wider spacing to allow the implementation of electrical connections at the front of the measuring device  1 .  
         [0052]     The measuring-device modules do not have their own power supply, but are supplied with electrical energy from a common current and voltage supply via the bus system formed on the plug-and-socket panel  11 . For this purpose, a further plug element  13  is formed on the plug-and-socket panel  11  by means of which the plug-and-socket panel  11  is connected to a power pack, which is not shown in  FIG. 2 . Via the plug-and-socket panel  11 , the power pack therefore supplies the necessary electrical energy for all the electrical and electronic components arranged in the measuring device  1 , including the information-output device  9 .  
         [0053]     Communication between an input/output device and/or the information-output device  9  connected to the measuring device  1  and the individual measuring-device modules takes place exclusively via the bus system formed on the plug-and-socket panel  11 . By preference, a USB (Universal Serial Bus) system can be used in this context. The plug-and-socket panel  11  is mounted in a floating manner within the receiving device  10 . Screws  28 , which are screwed through an extended recess in the plug-and-socket panel  11  to a component mounted on the receiving device  10 , but concealed in the diagram by the plug-and-socket panel  11 , are used to fix the plug-and-socket panel  11 . Within certain limits defined by the extended recess, the plug-and-socket panel  11  can be displaced relative to the receiving device  10 . The plug-and-socket panel  11  is also held by a clamping strip  29 . The clamping strip  29  consists of a number of spring clips, which additionally fix the plug-and-socket panel  11  and, via the clamping force, prevent the plug-and-socket panel  11  from being displaced too readily. The friction caused by a displacement damps the movement of the plug-and-socket panel  11  and, therefore, also of the measuring-device modules plugged into it.  
         [0054]     If the measuring-device module is displaced relative to the receiving device  10  on the basis of the guide device  15 , then the plug-and-socket panel  11 , which is connected to the measuring-device module via the relevant plug socket  12   a  to  12   e  and/or via the other plug sockets  27   a ,  27   b , can follow the movement of the fitted measuring-device modules. Accordingly, the plug-and-socket panel  11  experiences friction at the clamping strip  29 , thereby damping the movement of the inserted measuring-device modules.  
         [0055]     The guide device  15  is preferably structured in a symmetrical manner so that appropriately designed resilient tongues  14  and grooves  27  are introduced, respectively, into the cover of the receiving device  10 , which is not illustrated in  FIG. 2 . In total, ten plug positions are provided in the receiving device  10 , of which five are provided for receiving the measuring-device modules, two plug positions being provided for a computer module and the other three plug positions being reserved for a power pack. A guide device  15  with resilient tongues  14  is not provided in the region with the power pack. The individual measuring-device modules can be built up with different widths, so that several plug positions may be occupied by a single measuring-device module.  
         [0056]      FIG. 3  once again illustrates the receiving device  10  but, in this diagram, the cover  33  is also fitted. Moreover, the operating-panel carrier  16  is attached to the receiving device  10 . The receiving device  10  is fitted, for example, with a power pack  34  and two measuring-device modules  35  and  36 , the measuring-device module  35  being designed as a computer module. The space remaining at the rear of the receiving device  10  between the measuring-device modules  35  and  36  is occupied by unapertured-face blank elements  37  and  38 . Accordingly, the power pack  34 , the measuring-device modules  35  and  36 , and the blank elements  37  and  38  fully occupy the rear of the receiving device  10 . The blank elements  37  and  38  contact the measuring-device modules  35  and  36  or, respectively, the lateral wall of the receiving device  10  with lamellae, which will be described in greater detail below and which contributes to a screening of the measuring-device modules from electromagnetic radiation.  
         [0057]     In order to achieve a unified visual appearance and a robust housing for the measuring device  1 , an upper housing part  39  is placed onto the receiving device  10 , which, together with a lower housing part  40 , forms the visible, external measuring-device housing  2  of the measuring device  1 . The measuring-device modules  35  and  36  and the power pack  34  are fixed in the receiving device  10 , into which the measuring-device modules are initially only inserted, by means of a rear cover  41  of the measuring-device housing. The rear cover  41  of the measuring-device housing provides an opening  42 , through which the sides of the measuring-device modules  35  and  36  facing towards the rear of the receiving device  10  and the power pack  34  are accessible. A second opening  43 , which is separated from the opening  42  for the measuring-device modules  35  and  36  by a Web  44 , is provided for the power pack  34 .  
         [0058]     In order to cover the visible transitions between the measuring-device modules  35  and  36  and the blank elements  37  and  38 , insertion elements  45  are inserted in the rear cover  41  of the measuring-device housing. For this purpose, receiving recesses  48  are formed at an upper edge  46  and a lower edge  47  of the opening  42 , into which the insertion elements  45  are inserted. The gaps which occur between the measuring-device modules  35  and  36  and the blank elements  37  and  38  are covered by the insertion elements  45 , so that when the rear cover  41  is in place, a visually unified overall impression of the measuring device  1  is formed.  
         [0059]     By contrast with the other measuring-device modules, the power pack  34  has its own cooler. For this purpose, a fan  50  is attached at the rear side of the power pack  34 , which causes a flow of cooling air through the interior of the power pack  34 , lateral inlet openings  51  being provided for the flow of cooling air. The inlet openings  51  are arranged in a lateral wall of the receiving device  10 . Slots  52  are formed at a corresponding position in the lower part of the housing.  
         [0060]     Furthermore, a power connection  53  is provided at the rear wall of the power pack  34 , by means of which the measuring device  1  can be connected to a power cable. A main switch  54  is provided in order to switch the measuring device  1  on and off. This main switch  54  is used for the complete isolation of the device. For a normal operational interruption, the measuring device  1  can be switched on and off via a standby switch arranged on the front panel.  
         [0061]      FIG. 4  once again shows the receiving device  10 , wherein the measuring-device modules  35  and  36  are shown withdrawn from the measuring device. Each of the measuring-device modules  35  and  36  is connected via a contact strip  55  or  56 , respectively, to one of the plug sockets  12   a  to  12   e  or  27   a  or  27   b  respectively. At the side of the measuring-device module  36  opposite to the contact strip  56  of the measuring-device module  36 , which faces towards the rear of the measuring device, electrical contacts  57 ,  57 ′, and  57 ″ are formed, which can be input or output contacts for each of the relevant measuring-device modules. The measuring-device module  36  is provided for processing measurement signals, which originate from the device under test (DUT). The devices to be tested may be connected, for example, to one of the connections  57 ,  57 ′, or  57 ″. A measurement signal of this kind is processed entirely within the measuring-device module  36 . The parameters, which are required for processing an incoming signal of this kind, are supplied to the measuring-device module  36  via the bus system of the plug-and-socket panel  11  and the contact strip  56 .  
         [0062]     Testing a device in this manner leads to the output of a data record from the measuring-device module  36 , the data record being made available via the contact strip  56  through the measuring-device module  36  and the bus system of the plug-and-socket panel  11 , to other measuring devices or to the information-output device  9  for display. In the exemplary embodiment presented, as already described with reference to  FIG. 1 , the connection  6 , which is accessible from the front of the measuring device  1 , is formed on the measuring-device module  36  in addition to the electrical connections  57 ,  57 ′,  57 ″ at the rear of the measuring device  1 . Both the electrical connection  6  and also the electrical connections  57 ,  57 ′, and  57 ″ are used for the input and output of signals, which are required for the measurement, including, for example, trigger signals, wherein the processing of a measured signal takes place exclusively within the measuring-device module. The data record determined in this manner can be further processed in other measuring-device modules or external computer units or can be presented via a display device.  
         [0063]     By contrast, the measuring-device module  35  is designed as a computer module and is connected via the contact strip  55  to the information-output device  9 . This computer module controls the USB bus used jointly by the measuring-device module  36  and the computer module. At the side facing towards the rear of the measuring device  1 , a connection  58  is provided on the measuring-device module  35 , inter alia, for an additional monitor device.  
         [0064]     On the blank element  37  arranged between the measuring-device module  35  and the measuring-device module  36 , lamellae  59  are formed on both sides facing the measuring-device modules  35  and  36 , which are in contact with the measuring-device modules  35  and  36  in the rear region of the measuring-device modules  35  and  36 , when the measuring-device modules  35  and  36  are plugged into the measuring device  1 . The lamellae  59  are manufactured from a conductive material, so that they contribute to the screening of the measuring-device modules  35  and  36  arranged in the receiving device  10 . Lamellae, which achieve a screening of electromagnetic radiation, are also formed on both sides of the blank element  38  arranged between the measuring-device module  36  and the lateral wall of the receiving device  10 . These lamellae  59  of the blank elements  37  and  38  co-operate with corresponding lamellae, formed on each measuring-device module  35  and  36 , respectively, which will be explained in greater detail in connection with the structure of the measuring-device modules  35  and  36 . The lamellae are designed in the farm of flat metal clips, which can be subjected to resilient deformation and therefore achieve a secure contact with the adjacent structural component.  
         [0065]      FIG. 5  once again shows the receiving device  10 , with the blank elements  37  and  38  removed. Threaded boreholes  60  to the base  17  of the receiving device and to the cover  33  are provided in the blank elements  37  and  38 , so that the blank elements  37  and  38  can be screwed to the cover  33  and/or the base  17  of the receiving device  10 . For this purpose, screws  61  are screwed through the base  17  of the receiving device  10  and the cover  33  into the corresponding threaded boreholes  60 .  
         [0066]      FIG. 6  shows a first exemplary embodiment of the structure of a measuring-device module according to the invention. A first frame element  67  and a second frame element  68  act as bearing components of the measuring-device module. The two frame elements  67  and  68  are essentially rectangular, the first frame element  67  providing a groove  69  at its side facing towards the second frame element  68 , into which a high frequency sealing thread is inserted. The first frame element  67  and the second frame element  68  can be connected to one another along this groove  69  so that an enclosed base frame is formed along the groove  69  consisting of the first frame element  67  and the second frame element  68 . A main printed-circuit board  70  is mounted in this base frame.  
         [0067]     To accommodate the main printed-circuit board  70 , the first frame element  67  provides a mounting element  73  arranged on the inner periphery of the frame element  67 , onto which the main printed-circuit board  70  is placed.  
         [0068]     Centering elements  74  are preferably attached to the mounting element  73 , which determine the position of the main printed-circuit board  70  relative to the first frame element  67 . These centering elements  74  are preferably designed to be cylindrical in shape with multiple steps, and engage with at least one step in corresponding centering recesses  75  in the main printed-circuit board.  
         [0069]     Furthermore, a first projection  72   a  and a second projection  72   b  are formed on the main printed-circuit board  70 , which project beyond the first printed-circuit-board space  80  formed within the peripheral groove  69 . To allow the passage of the second projection  72   b , a milled recess  76  is provided in the second frame element  68 , which leaves free a slot slightly wider than the thickness of the main printed-circuit board  70  between the two frame elements  67  and  68 , when the first frame element  67  and the second frame element  68  are joined together. A corresponding milled recess, which is not shown in the diagram, is formed on the second frame element  68  for the first projection  72   a . The projection  72   a  passes through the milled recess and forms the contact strip  55 .  
         [0070]     The first frame element  67  and the second frame element  68  combine to form a base frame, in which the main printed-circuit board  70  is clamped. The first frame element  67  and the second frame element  68  fix the printed-circuit board  70  along the external periphery of the main printed-circuit board  70 . The majority of the area of the main printed-circuit board  70  is not covered by the frame elements  67  and  68 . The base frame produced in this manner provides a raised periphery  83  at each of its sides  81  and  82  facing away from one another, which is used for fixing cover plates  84  and  85  onto the base frame.  
         [0071]     The cover plates  84  and  85  enclose the base frame and accordingly form an enclosed first printed-circuit-board space  68 , in which the majority of the main printed-circuit board  70  is arranged. Since the cover plates  84  and  85  and also the first frame element  67  and the second frame element  68  are manufactured from a metallic material, the components arranged in the interior are shielded from electromagnetic radiation. The cover plates  84  and  85  are identical in structure, and the description below is therefore limited to the cover plate  85  illustrated in the foreground.  
         [0072]     At its edge  86 , the cover plate  85  provides an approximately 90° fold in the direction towards the second frame element  68 . In its exterior contour, the fold corresponds to the raised periphery  83  of the second frame element  68 . Like the raised periphery  83 , the fold on the outer edge  86  extends around three sides of the rectangular geometry of the base. Parallel to the fold on the edge  86  of the cover plate  85 , there are several beading strips  87 . 1  to  87 . 5  introduced into the cover plate  85 , wherein the beading strips  87 . 1  to  87 . 5  are also orientated as indentations in the direction towards the fold at the edge  86  of the cover plate  85 .  
         [0073]     A first connection element  88  and a second connection element  89  for connecting the main printed-circuit board  70  are arranged on the second projection  72   b  projecting from the first printed-circuit-board space  80 . The second projection  72   b  extends through the milled recess  76  from the first printed-circuit-board space  80  into a second printed-circuit-board space  90 . The second printed-circuit-board  90  is enclosed by frame arms  91  to  94  provided on the first frame element  67  and the second frame element  68 . When the first frame element  67  is connected to the second frame element  68 , the mutually facing surfaces of the frame arms  91  to  94  are therefore once again in flush contact with one another.  
         [0074]     The base frame consisting of the first frame element  67  and the second frame element  68  therefore forms a first printed-circuit-board space  80  and a second printed-circuit-board space  90 , wherein the first printed-circuit-board space  80  is enclosed at both sides of the main printed-circuit board  70  by a cover plate  84  and  85 , respectively. A second projection  72   b  of the main printed-circuit board  70  projects into the second printed-circuit-board space  90 . To allow the passage of the main printed-circuit board  70  into the second printed-circuit-board space  90 , a milled recess  76 , by means of which the first printed-circuit-board space  80  is connected to the second printed-circuit-board space  90 , is provided. In the exemplary embodiment illustrated, a connection element  88  and a second connection element  89  in the second printed-circuit-board space  90  are connected to the printed conductors of the main printed-circuit board  70 . A milled recess is also provided on the opposite short side of the measuring-device module, through which the first projection  72   a  projects from the first printed-circuit-board space  80 , the projection  72   a  being formed as a contact strip, which can be plugged into one of the plug sockets  12   a  to  12   e  or, respectively,  27   a  or  27   b.    
         [0075]     The measuring-device module shown in  FIG. 7  essentially corresponds in its structure to the measuring-device module shown in  FIG. 6 . However, instead of the cover plates  84  and  85 , cover plates  84 ′ and  85 ′, which are perforated with cooling-air apertures  95  to achieve improved cooling of the electronic components arranged on the main printed-circuit board  70 , are provided. To ensure continued, adequate screening, metallic covers, which prevent electromagnetic interference are attached to the main printed-circuit board.  
         [0076]      FIG. 8  shows a further advantageous embodiment of a measuring-device module  36  according to the invention. In this embodiment, the main printed-circuit board  70  has a third projection  72   c . Corresponding to the geometric extension of the third projection  72   c , a connection carrier  98  is formed on the first frame element  67 ′ and the second frame element  68 ′. For this purpose, a first connection-carrier element  98   a  is formed on the first frame element  67 ′. Along the outer edge of the first frame element  67 ′, a peripheral groove  69 ′ is once again formed, which also runs along the outer contour of the first connection-carrier element  98   a . Furthermore, an enclosed base surface  99  is formed in the region of the first connection-carrier element  68   a  on the side of the frame element  67 ′ facing towards the cover plate  84 ′.  
         [0077]     On the second frame element  68 ′, corresponding to the first connection-carrier element  98   a , a second connection-carrier element  98   b  is provided, which also has a base surface, which is not visible in the diagram, so that the third projection  72   c  of the main printed-circuit board  70  is enclosed, when the first frame element  67 ′ and the second frame element  68  are combined to form a base frame. While an extremely small gap for the passage of the third projection  72   c  is formed in the transitional region between the first printed-circuit-board space  80  and the connection carrier  98 , an enlarged free space  99 ′ is formed by a gradation of the base surface  99  at the end of the connection carrier  98  facing away from the first printed-circuit-board space in which sufficient space is available to provide a connection of the main printed-circuit board  70  to the third projection  72   c  by an electrical connection  100 .  
         [0078]     The electrical connection  100  is screwed onto the end face of the connection carrier  98 , an additional fastening surface  101  being formed on the second connection-carrier element  98   b  in the exemplary embodiment illustrated. In dependence upon the installation position of the corresponding measuring device module within the measuring device  1 , the additional fastening surface  101  may also be formed on the first connection-carrier element  98   a.    
         [0079]      FIG. 8  illustrates the measuring-device module  36 , as shown in  FIG. 4 . The measuring-device module is composed of two base elements  65  and  66 , the base element  65  corresponding to the base element described with reference to  FIG. 7 . The base element  66 , which is connected to the base element  65  in the region of the frame arms  91  and  92 , is additionally present. The frame arms  91  to  94  are thicker than the part of the first frame element  67 ′ and the second frame element  68 ′ enclosing the first printed-circuit-board space  80 , so that the frame arms  91  and  92  can be brought into contact with the frame arms  93  and  94  of the base element  65 . Together with the frame arms  91  to  94  of the base element  65 , the frame arms  91  to  94  of the base element  66  therefore enclose a common structural space, which is described as the additional printed-circuit-board space  90 ′.  
         [0080]     An additional printed-circuit board, which is not illustrated here, but which provides the connection of the main printed-circuit board  70  of the base element  66  to a further main printed-circuit board  70  of the base element  65  may, for example, be arranged in this additional printed-circuit-board space  90 ′.  
         [0081]      FIG. 9  once again shows the measuring-device module  36 , with the two base elements  65  and  66  already combined. While the frame elements  67  and  68  or, respectively,  67 ′ and  68 ′ are screwed together, the cover plates  84 ′ and  85 ′ are merely placed in position. To prevent a displacement on the relevant base frame, the outer edges  86  of the cover plates are, as already described, folded in such a manner that they engage around a corresponding, raised periphery  83  formed on the relevant frame element  67 ,  68 ,  67 ′, or  68 ′. Clip elements  102  are provided to fix the cover plates  84 ′ and  85 ′ to the base frame of the base elements  65  and  66 .  
         [0082]     The clip elements  102  are formed as a U-shaped profile, which extends along a length, which is at most equal to the length of the beading strips  87 . 1  to  87 . 5 . In this context, the two arms of the U-profile are formed from a row of individual spring clips  103 . 1  to  103 . 9  or, respectively, on the opposite side,  104 . 1  to  104 . 9 . The spring clips  103 . 1  to  103 . 9  and  104 . 1  to  104 . 9  are jointly arranged on a carrier surface  105 . The width of this carrier surface  105  is determined by the width of the base frame.  
         [0083]     In the opposite direction to the direction in which the spring clips  103 . 1  to  103 . 9  and  104 . 1  to  104 . 9  extend from the carrier surface  105 , a pair of curved projections  106  is punched out of the carrier surface  105  to form a guide element. In this context, the distance between the mutually facing edges of the punched-out, curved projections  106  is slightly larger than the lateral extension of the resilient tongues  14 . By contrast, the distance between the edges of the punched-out curved projections  106  facing away from one another corresponds to the width of the groove  27  in the receiving device  10 . The punched-out, curved projections  106  arranged respectively in pairs on the carrier surface  105  of the clip elements  102  accordingly co-operate with the guide component  15  of the receiving device  10  to form a guide device for the respective measuring-device module.  
         [0084]     The clip elements  102  are pushed from the external periphery over the cover plates  84 ′ and  85 ′ placed on the base frame until locking projections  107 , which are arranged on each spring clip  103 . 1  to  103 . 9  and  104 . 1  to  104 . 9  at the end facing away from the carrier surface  105 , snap into the beading strips  87 . 1  to  87 . 5 . In this context, the length of the spring clips  103 . 1  to  103 . 9  and  104 . 1  to  104 . 9  is dimensioned in such a manner that the carrier surface  105  is in contact with the base frame. This guarantees that the force transferred from the resilient tongues  14  to the measuring-device module is actually transferred to the measuring-device module and does not merely lead to a displacement of the clip elements  102  on the base element.  
         [0085]     A clip element  102 ′, which has a slot  108  in its carrier surface  105 ′, through which the projection  72   a  of the main printed-circuit board  70  passes, is also arranged at the end of a base element facing towards the front of the measuring device  1 . Because of the connection carrier  98 , the clip element  102 ′ is shorter than the other clip elements  102 . To continue to surround the slot  108  so that it is enclosed by the carrier surface  105 ′, the respective first spring clips  103 . 1 ′ and  104 . 1 ′ are designed with a bevel.  
         [0086]     On the opposite side of the measuring-device module  36 , the open, additional printed-circuit-board space  90 ′, in which the first connection element  88  and the second connection element  89  are screwed to the second projection  72   b  of the main printed-circuit board  70  of the base element  65 , is covered by a housing cover  110 . The housing cover  110  covers three sides of the additional printed-circuit-board space  90 ′ formed by the frame arms  91  to  94  of the base element  65  and the frame arms  91  to  94  of the base element  66 . The housing cover  110  has lateral cheeks  111  and  112 , of which the extension in the direction towards the electrical connection  100  is greater than the length of the frame arms  91  to  94 . Accordingly, the lateral cheek  111  overlaps the cover plate  85 ′ and the lateral cheek  112  overlaps the cover plate  84 ′. Each of the cover plates  84 ′ and  85 ′ is then screwed, together with the lateral cheeks  111  and  112 , respectively, to one of the frame elements. Accordingly, by means of the joint screw connection of the lateral cheeks  111  and  112  to the cover plates  84 ′ and  85 ′, respectively, contact with the relevant base element is ensured even in the region in which the cover plates  84 ′ and  85 ′ cannot be fixed with a clip element  102 .  
         [0087]     Furthermore, a region is provided in the lateral cheek  111 , in which the lamellae  59 , already mentioned with reference to the blank elements  37  and  38 , are arranged. The lateral cheeks  111  and  112  are connected to one another via a rear wall  113 , connection apertures  114 ,  114 ′, and  114 ″ being provided in the rear wall  113 , through which the electrical connections  57 ,  57 ′, and  57 ″ project from the housing cover  110 , when the housing cover  110  is placed onto the measuring-device module  36 .  
         [0088]     In the exemplary embodiment illustrated, a further fan  115  is provided in the housing cover  110 , which is used to increase the air flow in the region of the base elements  65  and  66 . A gap is provided between the mutually facing cover plate  85 ′ of the base element  66  and the cover plate  84 ′ of the base element  65 , which allows a through flow of cooling air. To manufacture a gap of this kind, the size of which is determined by the grid dimension of the guide devices  15  in the receiving device  10 , spacing elements are provided between the base elements  65  and  66  in the region of the frame arms  91  and  92  of the base element  66  and the frame arms  93  and  94  of the base element  65 . These will be explained with reference to  FIG. 10 .  
         [0089]     In the simplest case, a measuring-device module is represented by a single base element, as shown in  FIG. 10 . The grid dimension, in which the guide devices  15  are arranged within the receiver device  10 , is determined by the structural width of a measuring-device module of this kind. As already mentioned in the explanation of the connection of more than one base element, with a base element of this kind, the maximum structural width is in the region of the frame arms  91  to  94 .  
         [0090]     The material thickness of the lateral cheeks  111  and  112  of the housing cover  110  is added to this structural width. If the measuring-device module is composed of two base elements, as in the case of the measuring-device module illustrated in  FIG. 9 , then the lateral cheeks  111  and  112 , respectively, which are arranged between the frame arms  91  to  94  of two base elements, are dispensed with because of the common housing cover  110 . Accordingly, if two base elements are combined to form a measuring-device module, then two spacing elements are inserted between the two base elements to ensure that the grid dimension is maintained.  
         [0091]     In this context, the spacing elements  120  have an external contour  121 , which corresponds with the external contour of the lateral cheeks  111  and  112 , respectively. Accordingly, one part of the spacing elements  120  overlaps the corresponding cover plate  84 ′ or  85 ′, respectively, of the base elements  65  or  66 , respectively, which are to be connected in such a manner that the corresponding cover plates  84 ′ and  85 , respectively are also fixed in the region of the transition between the first printed-circuit-board space  80  and the additional printed-circuit-board space  90 ′. Furthermore, the spacing elements  120  have an internal contour  122 , which corresponds with the internal geometry of the second printed-circuit-board space  90  formed by the frame elements  67  and  68 , together with the frame arms  91  to  94 .  
         [0092]      FIG. 11  once again shows the complete measuring-device module  36 , the structure of which has already been explained in detail with reference to FIGS.  6  to  10 . The measuring-device module  36  provides an electrical connection  100  facing towards the front of the measuring device  1 , which can be formed, for example, as an N-socket or an ONC-socket. Three electrical connections  57 ,  57 ′, and  57 ″, which are designed as conventional connections for measuring devices, are arranged at the end of the measuring-device module  36  facing towards the rear of the measuring device  1 . The measuring-device module  36  therefore has connections facing the front of the measuring device  1  and also facing the rear of the measuring device  1 , so that, in the event of a simple change of the device under test, the measuring device  1  can still be operated exclusively from the front.  
         [0093]      FIG. 12  once again shows the front of the measuring-device module  36 . The electrical connection  100  is attached to the connection carrier  98 , which is composed of the first connection carrier element  98   a  and the second connection carrier element  98   b . As already explained in the description relating to  FIG. 8 , an enlargement of the volume surrounded by the connection carrier  98  in the direction towards the electrical connection  100  is achieved by a gradation of the base surface  99 , which forms the outer limit of the connection carrier. As a result of this widening of the first connection-carrier element  98   a , a mounting surface  125 , which is composed of the front faces of the first connection carrier element  98   a  and  98   b , is also enlarged. To allow an enlargement of this kind of the mounting surface  125 , an additional attachment surface  101  is provided on the second connection-carrier element  98   b . This surface  101  is used only to receive the electrical connection  100 , but does not lead to an enlargement of the interior volume of the connection carrier  98 .  
         [0094]     In dependence upon the plug position in which the measuring-device module is inserted, the connection-carrier element  98   b  can also be provided with the gradation in order to enlarge the structural space and the additional attachment surface  101  can be formed on the first connection-carrier element  98   a . The guide components  15  used to receive measuring-device modules, which have a connection-carrier  98 , are provided with a larger gap because of the increased space requirement.  
         [0095]     To improve the flow of cooling air, the spacing elements  120  can also be designed in two parts. Two-part spacing elements of this kind are shown in  FIG. 13  with the reference numbers  126  and  126 ′. The spacing between base elements in this context is provided only in the region of the frame arms  91  to  94 , so that the flow of cooling air entering between the cover plates  84  and  85  extends into the region of the spacing elements  126  and  126 ′, where it flows into the additional printed-circuit-board space  90 ′. The cooling of the measuring-device module is considerably improved especially when using an additional fan  115 .  
         [0096]      FIG. 14  shows a measuring-device module  35  designed as a computer module. The measuring-device module  35  comprises a base element  66 ′ and is connected at its end facing the rear of the measuring device to a frame body  127 , which supplements the second printed-circuit-board space  90  forming an additional printed-circuit-board space  90 ′. The internal geometry of the frame body  12 . 7  corresponds to that of the spacing elements  120 ; however, its thickness corresponds to the width of the frame arms  91  to  94  of a base element. With a frame body  127  of this kind, a base element  66 ′ is supplemented in such a manner, that the additional printed-circuit-board space  90 ′, previously discussed in relation to the measuring-device module  36 , is formed, without the need to connect a complete, second base element to the base element  66 ′. Spacing elements  120  are again inserted between the base element  66 ′ and the frame body  127 , so that the overall width of the measuring-device module  35  is once again a multiple of the grid dimension.  
         [0097]     Various connections of the computer module project through the housing cover  110 ′ including, inter alia, a video connection for connecting a monitor device. Furthermore, a row of additional connections  130 ,  131 ′, and  130 ″ is provided, with which the computer module can be connected, for example, to a network and additional input and output devices.  
         [0098]      FIG. 15  shows the computer module  35  from a second perspective. The diagram clearly shows how the frame body  127  supplements the structural width in the region of the second printed-circuit-board space  90  forming the additional printed-circuit-board space  90 ′. This additional printed-circuit-board space  90 ′ is again enclosed by a common housing cover  110 .  
         [0099]     During the construction of the measuring device  1 , two computer modules may also be provided; however, this is not illustrated. One computer model is used for communication with the information-output device  9 , while the second computer module is used to control the measuring device  1  via external input and output devices and/or via a network, such as Ethernet.  
         [0100]     In this context, the individual measuring-device modules form complete functional units, which, with an appropriate power supply, can also be operated outside the measuring device. This offers the advantage that an individual measuring-device module can be calibrated and the measuring-device modules calibrated in this manner can be interchanged. In particular, in the event of a retrospective replacement of a measuring-device module, for example, because of a fault, considerable cost savings can be achieved.  
         [0101]     While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.