Abstract:
An industrial or manufacturing communication system and devices typically used in an industrial environment including several industrial devices such as work stations wherein a work station power distribution line runs along side the work flow or conveyor line, with individual data units connected between the individual work stations and the power distribution line, and further includes a similar connection by a data unit between a process controller and the power distribution line, wherein a selective flow of data is provided between and/or among the individual work stations and/or a workstation and the process controller. Further embodiments include the powering of the data units from power derived from the power distribution line(s), and integration and/or embedding some or all of the communications elements of the present invention into the structure, e.g. circuit boards, of the workstations and other devices connected to primary and/or secondary power lines.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to data communication systems, in particular, to Ethernet-centric industrial process multi-point data communication systems between and among process workstations and process monitor and control devices. 
       BACKGROUND OF THE INVENTION 
       [0002]    Industrial environments and processes include manufacturing or processing sub-components that are located or are arranged in parallel and/or in sequence until the end of the process. Each manufacturing or processing sub-component often communicates with other sub-components or a controller, typically a programmable logic device, e.g. a specialized processor. Due to the nature of the industrial process, such sub-components are widely physically distributed in a somewhat hostile industrial environment, yet is required to be tightly integrated to maintain efficient execution of the process, which requires flexible and easy installation and reliable operation over the lifetime of the industrial process. 
         [0003]    One example  50  of a prior Ethernet-centric data communication between workstations  52 A- 52 F along a manufacturing line  40  is shown in  FIG. 1 , wherein each workstation  52 A- 52 F are individually connected, typically via CAT-5 cabling  54 A- 54 F, to a common network switch  56  which allows data communication between a process control computer  58  and one or more of the workstations  52 A- 52 F. However, each individual connection cabling  54 A- 54 F must make a “home run” to the possibly distant network switch  56 , often physically harsh environment and through an electrically ‘dirty’ environment which severely limits signal fidelity and bandwidth which significantly increase the costs and maintenance. 
         [0004]    A second example  60  of a prior data communication system is seen in  FIG. 2 , which ‘daisy-chains’ together Ethernet switches  62 A- 62 F, wherein each switch  62 A- 62 F is connected to a corresponding workstation  52 A- 52 F, and to the succeeding and preceding switch. However, failure one of the switches  62 A- 62 F, (and Programmable Logic Controller  58  optional switch  62 G) or other interruption or signal corruption in the data path connecting the switches  62 A- 62 F,  62 G interferes or stops subsequent signal flow and disables the manufacturing process in a “bus” topology. In the event of a “ring” configuration protection topology (mode), the recovery ring will re-establish the loop (ring), but in the event of a ‘non-clean’ break, e.g. an intermittent connection, further degradation occurs with oscillation between primary and secondary recovery modes. 
         [0005]    Meanwhile, in either prior systems and in many industrial processes, an entirely separate power distribution line  70  is run generally along the conveyor or product flow of the manufacturing process. Such power distribution lines provide a power to the industrial process typically in the range of 12 VDC to 48 VDC, but not limited thereto, and as a result of the various equipment connected thereto additionally have severe amounts of noise often spectrally concentrated at certain frequencies (and their harmonics) which may change according to the industrial process demand. 
       SUMMARY OF THE INVENTION 
       [0006]    An embodiment of the present industrial communication system and devices are typically used in an industrial environment with a process that includes a number of workstations or process operations along the work flow or the conveyor line, and includes the workstation power distribution line running along side the work flow or cell-based manufacturing line, with individual data units connected between the individual workstations and the power distribution line, and may further include a similar connection by a data unit between a process controller and the power distribution line, wherein a selective flow of data is provided between and/or among the individual work stations and/or a workstation and the process controller. 
         [0007]    Further inventive features include a secondary or redundant power distribution line to which the individual data units may also be connected and data selectively transmitted therethrough for additional bandwidth, alternate control signals or a substitute primary data path in the event of primary power line failure or deteriorated transmission quality. Moreover, the present invention includes embodiments that differentially apply to and receive from the power line(s) signals having dynamically adjusted spectrum (including signal carriers, sidebands and/or notches) which may adapt to the existing level of non-DC noise present. Further embodiments include the powering of the data units from power derived from the power distribution line(s), and integration and/or embedding some or all of the communications elements of the present invention into the structure, e.g. circuit boards, of the workstations and other devices connected to primary and/or secondary power lines. 
         [0008]    The embodiments of the present invention provide a robust, reliable, flexible, easily installed or modified, and relatively low maintenance cost communication system, uniquely adapted to the existing, often harsh industrial environment and the existing infra-structures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0009]    These and further features of the present invention will be better understood by reading the following Detailed Description together with the Drawing, wherein 
           [0010]      FIG. 1  is a block diagram of a prior art data distribution system having a traditional switch architecture; 
           [0011]      FIG. 2  is a block diagram of a prior art data distribution system having a low port count switch in a daisy-chain logical bus or ring architecture; 
           [0012]      FIG. 3  is a block diagram of an exemplary embodiment of the present invention; 
           [0013]      FIG. 4  is a block diagram of further details of a portion of an exemplary embodiment of the present invention; 
           [0014]      FIG. 5  is a block diagram of a sub-portion of an exemplary embodiment of the present invention; and 
           [0015]      FIG. 6  is a block diagram of an embedded embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    An exemplary embodiment  80  according to the present invention is shown in  FIG. 3 , wherein a cell-based manufacturing line  40  is associated with various manufacture or process steps, components or locations along which a number of workstations  52 A- 52 F are generally placed, and may be similar or different. The number of workstations is not limited. The workstations  52 A- 52 F may directly interact with the manufacturing product or step and/or may include or involve human interaction. Each workstation  52 A- 52 F receives operating power from power supply mains  70 , e.g. a 11-48 VDC power line running generally together with the manufacturing line  40 . Each workstation  52 A- 52 F has a corresponding data (interface) unit  82 A- 82 F, is also connected to the manufacturing supply mains  70  through which data is sent and received to other data units, and in most embodiments, data unit operating power is also received. In the exemplary embodiment, the individual workstations  52 A- 52 F selectively communicate with each other, and/or with a programmable logic controller (e.g. a process control computer)  58  via the manufacturing supply  70  through its own data unit  82 G. 
         [0017]    A further detail of a portion of an exemplary embodiment is shown in  FIG. 4 , wherein an exemplary data unit  92  is connected to a manufacturing power supply  72 P distributed by manufacturing supply line  70 P via connection path  74 P. In many instances the manufacturing supply line  70 P comprises two or more parallel or twisted wires. If such plural manufacturing supply wires are used, one embodiment of the present invention provides plural wires in the connecting path  74 P, optionally of similar (parallel, twisted, etc.) kind. Notwithstanding the intended purpose of providing a substantially constant-voltage power to loads along the manufacturing line, according to the present invention, the plural supply wires may further be differentially driven with the data unit signals, e.g. by a transformer or isolation transformer winding or equivalent, connected across power line wires. In a broad exemplary concept, the Power Line Device (PLD) which places data on an DC power line, the Programmable Logic Controller (PLC), necessary Band-Pass, Low-Pass and/or High-Pass filtering (BPF), and controlled workstation Device (Dev) may be consolidated in a single apparatus  94  within the data unit  92 , and may, in some embodiments, include the workstation apparatus or devices. The consolidated apparatus  94  is also powered by the manufacturing supply line  70 P. 
         [0018]    In manufacturing or conveyor application embodiments having redundant, back-up or secondary power supplies  72 S, and secondary connecting line  70 S, having wires similar or dissimilar to what is the primary line  70 P. According to one embodiment of the present invention, the consolidated apparatus  94  of the data unit  92  is connected to the secondary lines  70 S for data sending and/or receiving, operating power, or both with a connecting path  74 S similar or dissimilar to the connecting path  74 P. When both primary  70 P and secondary  70 S lines are used to power the data unit, power steering devices  96 P,  96 S are used to selectively receive power from either or both primary  70 P and secondary  70 S lines (via optional internal Low-Pass Filters) without interference or unwanted power or signal flow, and are shown in one embodiment as each represented by a diode. 
         [0019]    The consolidated device  94  receives data from either or both primary  70 P and/or secondary  70 S power lines with a hardware or software switch, selector, combiner, etc. (not shown) within the consolidated device. Similarly, the data unit  92  and/or consolidated device  94  include hardware or software switch, selector, output driver or connection of data signals provided to either or both primary  70 P and/or secondary  70 S lines. In alternate embodiments where distinct data is provided over different power lines (e.g.  70 P,  70 S) to which the data unit is connected, incoming and outgoing data isolation is also provided in the hardware or software switch, selector, combiner, output driver, etc. with an appropriate data isolator or data isolation process. 
         [0020]    Moreover, the present invention may include other data connections, such as to a programmable logic controller  58  as shown in  FIG. 3 , or another network  104  such as a Local Area Network (LAN) or Wide Area Network, Ethernet, or other network with a corresponding PLD data unit  102  providing an interface to an exemplary supply line, e.g.  70 P. 
         [0021]    A different configuration is shown in  FIG. 5 , wherein the devices  100  are external to the data unit  92 A and are connected to one or more supply lines with connecting path  74 P (and/or optionally connecting path  74 S). Often data unit  98  operating power is dissimilar to the voltages needed, and a data unit power supply  95  is included. The power supply  95  is connected to a supply line (e.g.  70 P,  70 S) via an optional low-pass filter, and if connected to more than one, a power steering device, e.g. a diode (e.g.  96 P,  96 S of  FIG. 4 ), is used to provide power line isolation and energy steering into the power supply  95 . Data line interface devices such as filter(s)  97  which provide band-pass filtering of the data signals of interest and a low-pass filtered power connection to the power supply  95 , and/or PLD is also included within the PLC process controller in  FIG. 5 ,  98  and/or the other embodiments. 
         [0022]    In another embodiment, the industrial device  100 A of  FIG. 6  itself includes a communication section  102  or circuit board co-located with the embedded data unit circuitry  110  also receiving data and operating power from the power line  70 , and providing a communication path with the communication section  102  of the industrial device  100 A. In higher levels of integration, the data unit circuit  110  according to the present invention is integrated with the communication sections, and both are optionally integrated into the industrial device  100 A circuitry, signal and data processing, and/or circuit boards. In the simplified block drawing of  FIG. 6 , only a single power line  70  (and connecting path  74 ) is shown. However, multiple power lines, e.g. for primary and secondary/backup power lines  70 P and  70 S, above, are applicable to the industrial device  100 A as taught for the above embodiments. The power supply  95 A is connected to the power line  70  but selectively isolated by a low-pass filter that reduces unwanted signal from the power supply  95 A introduced to the power line  70 . The power supply  95 A provides operating power at least to the components of industrial device  100 A. The resulting industrial device is placed along the manufacturing line  40  with and among other (or similar) devices or workstation as shown in  FIG. 3 . 
         [0023]    The embedded data unit  110  includes a band-pass filter  112  which provides signals to and from the power line  70  via power line connection  74 , and provides data signals to and from the subsequent circuitry via an Analog Front End (AFE)  114  or equivalent transitional circuitry, the data circuitry often including an Ethernet data path  116  to the communication circuitry  102 . The typical PLD and the embedded board  110  may include therein a bi-directional communications transceiver ‘engine’ which functions to translate data to (and from) a data unit format from (and to) a format better suited for the power line  70 , connected to the power line  70  via the AFE  114  which bi-directionally converts the data signals to (and from) the communications engine to (and from) signals better suited to the power line  70 . The signals to (and from) the AFE  114  from (and to) the power line  70  pass through band-pass filters (or bi-directional filter)  112  which relatively reduce unwanted signals not associated with data unit and power line signals, and the associated power supply low-pass filter  106  selectively reduces signals generated by the power supply  95 A from entering the power line  70  from which the power supply receives its operating power and interfering with the signals within the BPF  112  pass band. The embedded board  110  may optionally include its own power supply,  95 B, also connected to the power line  70  via LPF  106 . When secondary or back-up power lines (e.g.  70 S) are used, the industrial device embedded board may include further switching and/or coupling elements to provide the desired signal connections from the data units selectively to one or both primary and secondary power lines, and such switching and/or coupling elements may be included within at least the BPF  112  and/or the AFE  114  and/or the board communications engine, and/or additionally and separate therefrom. 
         [0024]    While the industrial device  100 A may include the necessary workstation components and/or functions, the industrial device  100 A may further include an input/output (I/O) port connection  104  for connection to and control of external workstation apparatus, e.g. a robotic arm. 
         [0025]    In one embodiment of the present invention, the PLC, PLD, the AFE, and/or associated communication engines, together or individually produce wide-band signals applied to or received from the power line(s) which are not limited to single carriers, single channels, spectrum, or modes of modulation, but may include structures which provide real-time, agile and/or dynamically allocated signals in response to the signal and/or noise conditions of the connected power line(s). An exemplary modulation technique and apparatus is provided by DS2 technology of Marvel, Santa Clara, Calif., according to OFDM protocol, incorporated by reference, which is provided by the above-referenced data unit elements. 
         [0026]    Alternate embodiments having DC power of a different voltage range, are within the scope of the present invention. Moreover, while the protocol used is the Ethernet data protocol, other protocols may also be used. Further modifications of the present invention made by one of ordinary skill are within the scope of the present invention, which is not limited, except by the claims that follow.