Abstract:
An input/output (I/O) device for an automation control system includes a device housing containing control circuitry, the device housing being mountable to a support, a control power input for receiving control power from a first adjacent I/O device when connected thereto, the control power input configured to supply control power to the control circuitry, a control power output for outputting control power to a second associated adjacent I/O device, a field power input for receiving field power from the first associated adjacent I/O device when connected thereto, and a field power output for transmitting field power to the second associated I/O device. The field power input is selectively removable to prevent field power from being received by the I/O device from the first associated adjacent I/O device when connected thereto.

Description:
BACKGROUND INFORMATION 
     The present exemplary embodiment relates generally to the field of automation control systems, such as those used in industrial and commercial settings. It finds particular application in conjunction with techniques for providing, accessing, configuring, operating, or interfacing with input/output (I/O) devices that are configured for coupling and interaction with an automation controller, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications. 
     Automation controllers are special purpose computers used for controlling industrial automation and the like. Under the direction of stored programs, a processor of the automation controller examines a series of inputs (e.g., electrical input signals to the automation controller) reflecting the status of a controlled process and changes outputs (e.g., electrical output signals from the automation controller) based on analysis and logic for affecting control of the controlled process. The stored control programs may be continuously executed in a series of execution cycles, executed periodically, or executed based on events. The inputs received by the automation controller from the controlled process and the outputs transmitted by the automation controller to the controlled process are normally passed through one or more I/O devices, which are components of an automation control system that serve as an electrical interface between the automation controller and the controlled process. 
     Traditional I/O devices typically include a base configured to couple the I/O device with a bus bar or the like, a terminal block for communicatively coupling the I/O device with field devices, and an I/O module that includes circuitry for performing communication functions and/or logic operations. In operation, a traditional I/O device typically communicatively couples with field devices (e.g., sensors and actuators) via terminals of the terminal block such that the I/O device can receive input signals from the field devices and provide output signals to the field devices. 
     In many applications, a large number of bases are arranged in close proximity to each other along a bus bar mounted on a wall or other surface. Each base supports both a terminal block and an I/O module. This type of configuration is sometimes referred to as a slice I/O because each set of bases, modules, and terminal blocks appear to be a “slice” of a larger structure. 
     Traditional automation control systems receive power from a power source (e.g., an electrical grid or battery) through field power distribution (FPB) modules, which are specialized modules for providing power to components of the automation control system. Depending on the size and nature of a particular automation control system, different numbers and types of field power distribution modules may be required. Indeed, as modules (e.g., I/O modules) are connected with a power bus of a modular automation controller system, the type or amount of power may need to be changed or augmented. For example, in traditional systems, a particular type of FPB module may be required for powering analog I/O, and a different type of FPB module may be required for powering discrete I/O. Additionally, a single FPB module can only support a limited number of automation control system modules or devices. 
     FPB modules break the field power distribution to downstream components. An FPB essentially comprises a terminal block and I/O module that is configured to break field power while passing on control power. A new field power source can be supplied via the terminal block such that downstream field power can be different than upstream field power. As such, an FPB module essentially bridges the control power between adjacent I/O modules, while shunting the field power and offering an input connection to a different field power source. 
     BRIEF DESCRIPTION 
     In accordance with an aspect of the present disclosure, an input/output (I/O) device for an automation control system comprises a device housing containing control circuitry, the device housing being mountable to a support, a control power input for receiving control power from a first adjacent I/O device when connected thereto, the control power input configured to supply control power to the control circuitry, a control power output for outputting control power to a second associated adjacent I/O device, a field power input for receiving field power from the first associated adjacent I/O device when connected thereto, and a field power output for transmitting field power to the second associated I/O device. The field power input is selectively removable to prevent field power from being received by the I/O device from the first associated adjacent I/O device when connected thereto. 
     The field power input can include a pair of blade connectors protruding from the housing via at least one opening, the pair of blade connectors configured to mate with corresponding connectors of a field power output of the first adjacent I/O device, the blade connectors being selectively removable from the device housing of the I/O device. The field power input can further comprise an input housing including a connector body therein, the connector body including at least one pair of cantilevered arms between which a blade connector is received, the connector body further comprising a threaded bore in which a removable fastener is received, the removable fastener being engaged with the blade to restrict removal of the blade from the input housing. The removable fastener can include a screw having a terminal end thereof engaged in a slot of the blade, whereby the terminal end of the screw restricts withdrawal of the blade from the connector body. 
     The input/output device can further include a cover for covering the opening in the device housing when the blade terminals are removed therefrom. The cover can extend around at least a portion of two adjacent side of the device housing. The device housing can have a relatively wide side and a relatively narrow side, and the cover can extend around at least a portion of both the relatively narrow side and the relatively wide side. 
     The input/output (I/O) device can also include a terminal block having an input for receiving a second source of field power, whereby the second source of field power is delivered to the field power output when the field power input is removed. 
     In accordance with another aspect, an automation control system comprising a plurality of I/O devices mounted to a support and connected in series, at least one of the I/O devices being a field power break (FPB) I/O device as described herein. 
     In accordance with another aspect, a method for selectively breaking field power distribution in an automation control system comprises providing at least one I/O device including a device housing mountable to a support, a control power input for receiving control power from a first adjacent associated I/O device, the control power input configured to supply control power to the control circuitry, a control power output for outputting control power to a second adjacent associated I/O device located opposite the first adjacent associated I/O device, a field power input for receiving field power from the first adjacent associated I/O device, and a field power output for transmitting field power to the second adjacent associated I/O device, wherein the field power input is selectively removable to prevent field power from being received by the I/O device from the first associated I/O device, and selectively removing the field power input from the I/O device to break field power distribution. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatical representation of an exemplary control and monitoring system; 
         FIG. 2  is a perspective view of an I/O device in accordance with the present disclosure; 
         FIG. 3  is a perspective view of a pair of exemplary I/O modules in accordance with the present disclosure; 
         FIG. 4  is perspective view of the I/O modules of  FIG. 3  illustrated in coupled state; 
         FIGS. 5( a )-5( d )  are perspective views of an exemplary I/O module in various states during removal of the blade contacts and installation of the bus cap; 
         FIG. 6  is a perspective view of a field power break I/O module and an I/O module; 
         FIG. 7  is a perspective view of a pair of I/O modules with their housings removed to show the selectively removable contact assemblies thereof; 
         FIG. 8  is a perspective view of a pair of selectively removable contact assembly in a connected state; 
         FIG. 9  is a perspective view of a pair of selectively removable contact assemblies wherein one of the assemblies has its contacts removed; 
         FIG. 10  is a perspective view of a power connector main body with a blade contact installed; and 
         FIG. 11  is a perspective view of the power connector main body of  FIG. 10  with the blade contact removed. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a diagrammatical representation of an exemplary control and monitoring system adapted to interface with networked components and configuration equipment in accordance with embodiments of the present techniques. The control and monitoring system is generally indicated by reference numeral  10 . Specifically, the control and monitoring system  10  is illustrated as including a human machine interface (HMI)  12  and an automation controller or control/monitoring device  14  adapted to interface with components of a process  16 . 
     The process  16  may take many forms and include devices for accomplishing many different and varied purposes. For example, the process  16  may comprise a compressor station, an oil refinery, a batch operation for making food items, a mechanized assembly line, and so forth. Accordingly, the process  16  may comprise a variety of operational components, such as electric motors, valves, actuators, temperature elements, pressure sensors, or a myriad of manufacturing, processing, material handling, and other applications. Further, the process  16  may comprise control and monitoring equipment for regulating process variables through automation and/or observation. 
     For example, the illustrated process  16  comprises sensors  18  and actuators  20 . The sensors  18  may comprise any number of devices adapted to provide information regarding process conditions. The actuators  20  may include any number of devices adapted to perform a mechanical action in response to a signal from a controller (e.g., an automation controller). The sensors  18  and actuators  20  may be utilized to operate process equipment. Indeed, they may be utilized within process loops that are monitored and controlled by the control/monitoring device  14  and/or the HMI  12 . Such a process loop may be activated based on process inputs (e.g., input from a sensor  18 ) or direct operator input received through the HMI  12 . 
     As illustrated, the sensors  18  and actuators  20  are in communication with the control/monitoring device  14  and may be assigned a particular address in the control/monitoring device  14  that is accessible by the HMI  12 . As illustrated, the sensors  18  and actuators  20  may communicate with the control/monitoring device  14  via one or more I/O devices  22  coupled to the control/monitoring device  14 . The I/O devices  22  may transfer input and output signals between the control/monitoring device  14  and the controlled process  16 . The I/O devices  22  may be integrated with the control/monitoring device  14 , or may be added or removed via expansion slots, bays or other suitable mechanisms. For example, additional I/O devices  22  may be added to add functionality to the control/monitoring device  14 . Indeed, if new sensors  18  or actuators  20  are added to control the process  16 , additional I/O devices  22  may be added to accommodate and incorporate the new features functionally with the control/monitoring device  14 . The I/O devices  22  serve as an electrical interface to the control/monitoring device  14  and may be located proximate or remote from the control/monitoring device  14 , including remote network interfaces to associated systems. 
     The I/O devices  22  may include input modules that receive signals from input devices such as photo-sensors and proximity switches, output modules that use output signals to energize relays or to start motors, and bidirectional I/O modules, such as motion control modules which can direct motion devices and receive position or speed feedback. In some embodiments, the I/O devices  22  may convert between AC and DC analog signals used by devices on a controlled machine or process and DC logic signals used by the control/monitoring device  14 . Additionally, some of the I/O devices  22  may provide digital signals to digital I/O devices and receive digital signals from digital I/O devices. Further, in some embodiments, the I/O devices  22  that are used to control machine devices or process control devices may include local microcomputing capability on an I/O module of the I/O devices  22 . 
     In some embodiments, the I/O devices  22  may be located in close proximity to a portion of the control equipment, and away from the remainder of the control/monitoring device  14 . In such embodiments, data may be communicated with remote modules over a common communication link, or network, wherein modules on the network communicate via a standard communications protocol. Many industrial controllers can communicate via network technologies such as Ethernet (e.g., IEEE802.3, TCP/IP, UDP, EtherNet/IP, and so forth), ControlNet, DeviceNet or other network protocols (Foundation Fieldbus (H1 and Fast Ethernet) Modbus TCP, Profibus) and also communicate to higher level computing systems. 
       FIG. 2  is a perspective view of a plurality of I/O devices  22  connected to an I/O adapter  24  in accordance with embodiments of the present disclosure. Although only two I/O devices  22  are illustrated, it will be appreciated that any number of I/O devices can be used in accordance with the present disclosure. The I/O adapter  24  is configured to provide system power to the I/O devices  22 , as well as to enable conversion between the communications protocols of the I/O devices  22  and the control/monitoring device  14 . As illustrated, the I/O adapter  24  and the plurality of I/O devices  22  are mounted to a DIN rail  26 , which is an industry standard support rail for mounting control equipment in racks and cabinets. The plurality of I/O devices  22  are electrically coupled in series along the DIN rail  26  such that field power and system information and power may be communicated between the I/O devices  22 , and back through the I/O adapter  24  to the control/monitoring device  14 . In other embodiments, the DIN rail  26  may be replaced with a different type of mounting structure. It will be appreciated that the I/O devices can be used in a wide variety of configurations, and the arrangement illustrated in  FIG. 2  is merely exemplary in nature. 
     Each of the I/O devices  22  includes an I/O module  27  having a base portion  28  for physically and communicatively connecting the I/O device  22  to the DIN rail  26 , the I/O adapter  24  and/or adjacent I/O devices  22 . In addition, the base portion  28  of the I/O device  22  is configured to physically and communicatively connect the I/O device  22  with other I/O devices  22  via the DIN rail  26 , field and system electrical contacts as described in greater detail below, base connection features as described in greater detail below, and so forth. In addition, each of the I/O devices  22  includes a terminal block  30  (which, in certain embodiments, may be removable from the base  28 ) for electrically connecting the I/O device  22  to field devices, such as the sensors  18  and actuators  20  illustrated in  FIG. 1 . As described in greater detail below, in certain embodiments, each terminal block  30  may include status indicators that are directly aligned with (e.g., adjacent to or directly integrated with) terminals of the terminal block  30 . It will be appreciated that the I/O modules  27  include I/O control circuitry and/or logic. In general, the I/O modules  27  receive input signals from the field devices, deliver output signals to the field devices, perform general and/or specific local functionality on the inputs and/or outputs, communicate the inputs and/or outputs to the control/monitoring device  14  and/or the other I/O devices  22 , and so forth. 
     As shown in  FIGS. 3 and 4 , adjacent I/O modules  27  are coupled together and/or to the DIN rail  26  (not shown in remaining figures) by sliding or otherwise bringing the components together in alignment. Respective pairs of blade terminals  44  and  46  mate with corresponding fork connectors (not shown in  FIGS. 3 and 4 , but described in more detail below) to electrically couple the downstream I/O module  27  (right I/O module in  FIG. 4 ) with the upstream I/O module  27  (left I/O module in  FIG. 4 ). Blade contacts  44  carry field power while blade contacts  46  carry control power. 
     As described above, in the past a FPB module would be interposed between the I/O device  22  when it was necessary to break the field power distribution therebetween. 
     Turning to  FIGS. 5-11 , and initially to  FIG. 5 , it will be appreciated that the I/O modules  27  of the present disclosure obviate the need for a FPB module to break field power distribution to downstream components by facilitating a break through a selectively removable contact system. The selectively removable contact system allows a system designer to selectively remove the contacts of an I/O module to isolate a downstream I/O module from its adjacent upstream counterpart. By providing an I/O module with selectively removable contacts, the present disclosure allows systems to be constructed without FPB modules thereby decreasing costs and simplifying the process. 
       FIG. 5  illustrates an exemplary I/O module  27  in various states (a)-(d) as it is transformed from the state shown in  FIG. 5( a )  to the state shown in  FIG. 5( d ) , which will be referred to herein as a field power break (FPB) I/O module, and designated with a new reference numeral  50 . For clarity, the DIN rail and other components are not shown in the remaining figures. As will become apparent, the FPB field module  50  is outwardly identical to I/O module  27  except that the blade contacts  44  have been removed such that the field power is not passed to FPB I/O module  50  from an upstream I/O module  27 . As will also be described, an optional bus cap  52  can be installed to provide a physical barrier between adjacent I/O modules, and to provide a visual indication that a given I/O module is an FPB module  50 . 
       FIG. 5( a )  illustrates an exemplary I/O device  22  including an I/O module  27  in accordance with the present disclosure. The I/O device  22  includes a terminal block mounted to the I/O module  27 . Blade contacts  44  in the base portion  28  of the I/O module  27  are provided for connecting the I/O module  27  to an adjacent upstream I/O module in the manner described above. 
     In  FIG. 5( b ) , the blade contacts  44  are illustrated separated from the base portion  28  of the I/O module  27 . In this embodiment, screws  54  are used to retain the blade contacts  44  in the I/O module  27 . As will be appreciated, other fasteners and/or retention mechanisms can be used to secure the blade contacts  44 . 
     Once the blade contacts  44  are removed, a bus cap  52  can be installed over the opening in the base portion  28  from which the blade contacts  44  previously protruded. This is illustrated in  FIGS. 5( c ) and 5( d ) . The bus cap  52  will generally be made from an insulator material, such as plastic or the like. The bus cap  52  not only provides a barrier between the internal components of the I/O adaptor  24 , but extends to a front edge of the I/O device  22  to serve as a visual indicator the I/O module is a FPB I/O module  50 . This allows a system designer or technician to readily identify the FPB modules  50  by simply locating those I/O modules with a bus cap  52  installed. The bus cap  52 , or portion thereof that is visible when installed, can be colored with a specific color to assist in identification. In the illustrated embodiment, the bus cap  52  includes a tab  53  that cooperates with a slot on the I/O adapter  24  to retain the bus cap  52  thereto. 
     In  FIG. 6 , it will be appreciated that the FPB I/O module  50  can be installed adjacent I/O module  27  in an otherwise typical fashion. However, due to the removal of the blade contacts  44  and installation of the bus cap  52 , no field power connection will be made between the modules. 
     Turning to  FIGS. 7-11 , an exemplary selectively removable contact assembly will be described. The selectively removable contact assembly generally comprises a power connector housing  72  that is configured to mate with a PCB  74  and includes the blade and fork contacts for making the field power connection between adjacent I/O modules as described above. In  FIG. 7 , two such circuit boards  74  and power connector housings  72  are illustrated in a connected fashion with the housings of each I/O module removed for clarity. In the remaining figures, the PCB  74  associated with each power connector housing is not shown for clarity. 
     Turning to  FIGS. 8 and 9 , partial cutaway views illustrate a pair of power connector housings  72  in a physically coupled fashion. In  FIG. 8 , the power connector housings  72  are each associated with an I/O module  27  and thus field power connection is made between the I/O modules. In  FIG. 9 , the power connector housing on the right is associated with an FPB I/O module and thus no field power connection is made between the I/O modules. 
     In  FIG. 8 , each power connector housing  72  supports power connector main body  75  which includes a PCB connector  76  for electrically coupling with PCB  74 . The PCB connector  76  in the illustrated embodiment includes cantilevered arms  78  for gripping and connecting with contacts of the PCB  74 . The power connector main body  75  also includes a pair of blade and fork connectors  44  and  82  for coupling to the field power terminals of an adjacent I/O module. It will be appreciated that, in this embodiment, the blade connectors  44  are selectively removable and, as noted above,  FIG. 9  illustrates a pair of power connector housings wherein the blade contacts  44  have been removed from the power connector housing  72  on the right, and a bus cap  52  has been installed between the power connector housings  72 . 
     With reference to  FIGS. 10 and 11 , the power connector main body  75  and contacts are shown in isolation. The power connector main body  75  generally comprises a base portion  86  that is generally made of a conductive material such as a metal or metal alloy. Extending upwardly from the base portion is PCB connector  76  which, as noted, generally comprises a pair of cantilevered arms for compressive engaging a PCB. At one end of the base portion  86  are a pair of cantilevered arms comprising the fork connector  82 , and at the opposite end is blade connector  44 . A portion of blade connector  44  is supported between a pair of cantilevered arms  88  of the base portion  86  that define therebetween a slot. As best shown in  FIG. 11 , a screw  90  or other fastener is threaded or otherwise engaged with the base portion  86  to secure the blade  44  in the base portion  86 . A leading end of the screw is configured to engage in a slot  92  of the blade connector  44  to restrict withdrawal of the blade connector  44  when installed. 
     It will be appreciated that in one embodiment, the power connector main body  75  can be formed as an integral piece such as by suitable stamping operations or the like, with only the blade connector  44  and the screw  90  being separate, selectively removable components. In addition, the blade connector  44  can be secured to the base portion  86  in other manners such as snapfit connections and the like. 
     This description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.