In-place retrofit of PLC control systems

Abstract

To provide a method for upgrading part of a process control system from a legacy programmable logic controller (PLC) to a non-PLC process controller.SOLUTION: A mounting rack is sized to fit into a space occupied by legacy hardware, assembled, and populated with replacement hardware that includes an I / O card, a terminal block, and a custom interface module. The custom interface module is coupled to the I / O card via the I / O terminal block and to a plurality of process control field devices via a legacy wiring mechanism coupled to legacy wiring of the process control system, without requiring modification or re-termination of the legacy wiring. The legacy wiring mechanism is disconnected from the legacy hardware, the rack containing the legacy hardware is removed and replaced with the mounting rack, and the legacy wiring mechanism is coupled to the custom interface module.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present disclosure relates generally to input / output (I / O) wiring in process control plants, and more particularly to methods, systems, and apparatus for retrofitting older programmable logic controller (PLC)-based systems to systems using distributed process controllers without requiring re-termination of field device wiring. [Background technology]

[0002] Distributed process control systems, such as those used in chemical, petroleum, industrial, or other process plants, typically include one or more process controllers communicatively coupled to one or more field devices via an analog bus, a digital bus, or an analog / digital combination bus, or via a wireless communication link or network. The field devices, which may be, for example, valves, valve positioners, switches, and transmitters (e.g., temperature, pressure, level, and flow sensors), are positioned within the process environment and generally perform physical or process control functions, such as opening or closing valves, measuring process parameters, etc., to control one or more processes running within the process plant or system. Smart field devices, such as field devices conforming to the well-known Fieldbus protocol, may also perform control calculations, alarm functions, and other control functions typically implemented within a controller. A process controller, also typically located within a plant environment, executes a controller application that executes different control modules that receive signals indicative of process measurements made by and / or other information regarding the field devices, make process control decisions, generate control signals based on the received information, and interface with control modules or blocks that execute in the field devices, such as HART®, WirelessHART®, and FOUNDATION® Fieldbus field devices. The control modules within the controller send control signals over communication lines or links to the field devices, thereby controlling the operation of at least a portion of the process plant or system.

[0003] Information from the field devices and controllers is typically made available via a communications backbone to one or more other hardware devices, such as operator workstations, personal computers or computing devices, data historians, report generators, centralized databases, or other centralized computing devices, typically located in a control room or other location away from the more hostile plant environment. Each of these hardware devices is typically centralized throughout the process plant or throughout a portion of the process plant. These hardware devices execute applications that may enable operators to perform functions related to the control of the process and / or the operation of the process plant, such as, for example, changing settings on process control routines, modifying the operation of control modules in controllers or field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for purposes of training personnel or testing process control software, maintaining and updating configuration databases, etc. Utilizing the communications backbone by the hardware devices, the controllers and field devices may include wired communication paths, wireless communication paths, or a combination of wired and wireless communication paths.

[0004] For example, see the products sold by Fisher-Rosemount Systems, Inc. The DeltaV™ control system, commercially available, includes multiple applications stored in and executed by different devices located at various locations within a process plant. Configuration applications residing in one or more workstations or computing devices enable users to create or modify process control modules and download them to dedicated distributed controllers via a communications backbone. Typically, these control modules are composed of communicatively interconnected function blocks, which are objects in an object-oriented programming protocol that perform functions within a control scheme based on inputs and provide outputs to other function blocks within the control scheme. The configuration application may also enable process engineers to create or modify operator interfaces that are used by viewing applications to display data to an operator and allow the operator to change settings, such as setpoints, within a process control routine. Each dedicated controller, and in some cases, one or more field devices, stores and executes its own controller application, which executes the control modules assigned to and downloaded to it, to implement the actual process control functions. A viewing application may run on one or more operator workstations (or one or more remote computing devices communicatively connected to the operator workstations and the communications backbone), and the viewing application may receive data from the controller application via the communications backbone and display this data to a process control system designer, operator, or user using a user interface to provide any of several different views, such as an operator's view, an engineer's view, a technician's view, etc.While the data historian application is typically stored on and executed by a data historian device that collects and stores some or all of the data provided over the communications backbone, the configuration database application may be attached to the communications backbone and executed on a further remote computer to store the current process control routine configuration and associated data. Alternatively, the configuration database may be located on the same workstation as the configuration application.

[0005] In many processes, legacy programmable logic controllers (PLCs) are integrated into the process. For example, older portions of a process plant may have originally implemented PLCs to control those portions of the process plant. As a process plant has expanded or modernized, some portions of the process plant may have implemented non-PLC distributed control solutions (e.g., the DeltaV™ control system mentioned above), but the legacy PLC solutions remain in place, either already implemented or choosing to integrate the legacy PLCs into the new system. For a variety of reasons, integrating the legacy PLCs into the new system remains the preferred solution, typically involving a significant investment of time and effort.

[0006] One obstacle to retrofitting older PLC-based plant configurations is legacy wiring. Facilitating communication between field devices in a process plant and devices that implement the control strategies for operating those field devices, such as PLCs and controllers, typically involves running wires from the field devices to a marshalling cabinet or other centralized area where the wiring is organized or terminated. Typically, input signals from the field devices to the control system are grouped together, while output signals from the control system to the field devices are grouped together. Groups of wires (and the signals they carry) are further grouped by the type of signal carried by the wire (e.g., by voltage, whether the signal is discrete or analog, etc.) and grouped by the I / O interface device. An I / O interface device facilitates the communication of signals to a control device.

[0007] In some systems, for example, each group of wires may be terminated at an I / O card field termination connector that couples the signals carried on the wires to a corresponding I / O card by means of an associated swing arm, or a connector such as a card edge connector, contact connector, or the like, which typically has a higher signal density than the wires themselves. The use of a swing arm allows the wiring to be disconnected from the I / O card for maintenance or troubleshooting purposes; that is, by removing the swing arm from the I / O card, the I / O card can be removed and replaced when disconnected without having to individually separate (and then re-terminate) each of the many wires carried by the swing arm.

[0008] While the use of a swing arm facilitates movement of the wire bundle, that movement is limited by various factors. For example, as can be appreciated, large bundles of wire can be difficult to manipulate due to the relatively large amount of copper contained therein. Added to this difficulty is the fact that older wires, in particular, may become less flexible over time or may have weakened insulation that puts the wire at risk of breaking.

[0009] Another obstacle to retrofitting older PLC-based plant configurations is the consideration of available space. Typically, a process plant (or part thereof) does not leave much room for subsequent expansion, and as a result, retrofitting can be difficult without physically modifying the process plant (or part thereof) and significant process disruption (and associated costs). Newer control systems typically require space that is not available in the rack room housing the older PLC-based solution, and transmitting signals from the rack room housing the terminated signals to controllers in other available space can require long lengths of cable running through small spaces, which can result in signal crosstalk and, consequently, reduced reliability of the overall process. Summary of the Invention

[0010] In an embodiment, a method for upgrading a process control system from a legacy programmable logic controller (PLC) to a non-PLC process controller includes assembling a mounting rack. The mounting rack is sized and configured to fit into a space occupied by a rack housing legacy hardware associated with the legacy PLC. The method also includes installing replacement hardware in the mounting rack. The replacement hardware includes: a non-PLC process controller or a carrier extender configured to be communicatively coupled to the non-PLC process controller; an input / output (I / O) card communicatively coupled to the non-PLC process controller or the carrier extender in the mounting rack; an I / O terminal block communicatively coupled to the I / O card and configured to communicate I / O card signals corresponding to a plurality of process control field devices to and / or from the I / O card signals to the plurality of process control field devices, without requiring modification or re-termination of the legacy wiring. The method also includes disconnecting the old wiring mechanism from the old hardware associated with the PLC, removing the rack housing the old hardware associated with the old PLC, placing the assembled mounting rack including the replacement hardware in the space previously occupied by the rack housing the old hardware associated with the old PLC, and removing the old wiring mechanism from the rack housing the old hardware associated with the old PLC. and connecting the line mechanism to the custom interface module.

[0011] In another embodiment, the custom interface module includes a legacy wire connection mechanism configured to mechanically and electrically connect the custom interface module to a mating legacy wire connection mechanism. The mating legacy wire connection mechanism terminates legacy wiring for carrying a plurality of signals to or from a plurality of process control field devices. The custom interface module also includes an I / O connection mechanism configured to facilitate electrical coupling of the custom interface module to the I / O card, for each of the plurality of signals, such that a corresponding signal is communicated to or from the I / O card via the I / O connection mechanism. The custom interface module further includes an adjustment module electrically disposed between the I / O connection mechanism and the legacy wire connection mechanism, the adjustment module configured to, for each of the plurality of signals, (i) convert a signal received at the legacy wire connection mechanism into a signal that can be transmitted to the I / O card via the I / O connection mechanism, or (ii) convert a signal received from the I / O card via the I / O connection mechanism into a signal that can be transmitted to a corresponding process control field device via the legacy wire connection mechanism.

[0012] In yet another embodiment, a system for upgrading a process control system from a legacy programmable logic controller (PLC) to a non-PLC process controller includes a mounting rack sized and configured to fit into a space occupied by legacy hardware associated with the legacy PLC, a non-PLC process controller, and an input / output (I / O) card coupled to the non-PLC process controller and mounted in the mounting rack. The system also includes an I / O terminal block communicatively coupled to the I / O card and configured to pass to and / or transmit from the I / O card signals corresponding to a plurality of process control field devices. The I / O terminal block is mounted in the mounting rack. The system further includes a custom interface module mounted in the mounting rack and communicatively coupled (i) to the I / O card via the I / O terminal block and (ii) to the plurality of process control field devices via a legacy wiring mechanism coupled to the legacy wiring of the process control system without requiring modification or re-termination of the legacy wiring. [Brief explanation of the drawings]

[0013] The features and advantages of the methods, apparatus, and systems described herein will be best understood by referring to the following detailed description and accompanying drawings.

[0014] [Figure 1] FIG. 1 is a block diagram of a distributed process control system including a retrofitted legacy PLC control system and a non-retrofitted legacy PLC control system. [Figure 2A] Illustrates an example of an I / O chassis for an older PLC control system. [Figure 2B] 1 illustrates a swing arm connected to legacy field device wiring. [Figure 3] 2B illustrates a side view of the example I / O chassis of FIG. 2A. [Figure 4]10 illustrates an alternative embodiment of the swing arm. [Figure 5] 1 shows multiple swing arms for different styles and numbers of terminals. [Figure 6] 1 shows a plurality of swing arms with wires connected to the swing arms; [Figure 7] FIG. 1 is a block diagram of an exemplary I / O chassis for retrofitting a control system according to the present disclosure. [Figure 8] FIG. 8 is a side view of the I / O chassis of FIG. 7. [Figure 9] 1 illustrates an alternative embodiment of an I / O chassis for retrofitting a control system. [Figure 10] 10 illustrates yet another alternative embodiment of an I / O chassis for retrofitting a control system. [Figure 11] 1 illustrates yet another embodiment of an I / O chassis for retrofitting a control system. [Figure 12] 12 depicts a side view of the embodiment of FIG. [Figure 13] 1 illustrates a generic custom interface module according to the present disclosure. [Figure 14] 1 depicts a method for upgrading a portion of a process control system according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Generally speaking, the control system of the present disclosure includes various process control devices communicatively coupled to a distributed control system and one or more process control devices coupled to a legacy programmable logic controller (PLC), which may itself be integrated into the distributed control system or, alternatively, may be a standalone part of the process plant. That is, the PLC and process control devices coupled thereto may operate as standalone PLCs, controllers in a skid-mounted system, or modules in a modular plant architecture. The control system as a whole may be built natively on a platform such as DeltaV that supports distributed control, so that the configuration, security mechanisms, and communications of the devices therein, including, in embodiments, the legacy PLC, are fully compatible with the DCS into which the legacy PLC is integrated. In the present disclosure, the legacy PLC is replaced with hardware, including controllers and input / output (I / O) devices, native to the DCS without requiring relocation and / or re-termination of the legacy wiring that previously connected one or more process control devices to the legacy PLC. The process of replacing the legacy PLC and associated hardware with native DCS hardware is referred to herein as "retrofitting."

[0016] To facilitate the retrofit, the DCS controller and associated I / O hardware are mounted in a custom rack sized to fit into the space occupied by the older PLC hardware. The I / O hardware within the custom rack, and the custom rack itself, are configured to include connection hardware with custom interface modules positioned to couple to complementary connection hardware on the swing arms or other field device wiring termination hardware, as described herein, that couples to the older wiring for the field devices. Each of the custom interface modules is selected according to the older I / O hardware being replaced, such that a custom interface module for older wiring where input signals reside is an input-type custom interface module, a custom interface module for older wiring where output signals reside is an output-type custom interface module, and so on. Additionally, each of the custom interface modules may include signal conditioning circuitry that converts signals on the older wiring to which it will be connected to signals that can be directly coupled to the DCS via the associated I / O hardware.

[0017] As described in this disclosure, the method for retrofitting a control system simply requires disconnecting the old I / O wiring from the old I / O hardware and replacing the old I / O hardware with custom racks and connecting the old wiring to custom interface cards to communicatively couple field devices to the DCS controller through the new I / O hardware.

[0018] Next, an exemplary distributed process control system including a portion of the control system that is natively commissioned in a DCS, as well as a portion of the control system that operates according to a legacy PLC and a portion of the control system that is retrofitted from a legacy PLC, will be described with reference to FIG. Examples of hardware associated with portions of a control system that operate in accordance with an older PLC are depicted in Figures 2, 3, and 4. Examples of hardware associated with portions of a control system that have been retrofitted from an older PLC are described with reference to Figures 4 and 5.

[0019] FIG. 1 illustrates an exemplary process plant 10 implementing a native distributed control system 22, a legacy PLC control system 100, and a retrofit control system 101. As is typical, the distributed process control system 22 has one or more controllers 40, each of which is communicatively connected to one or more field or smart devices 44 and 46 via an input / output (I / O) device or I / O card 48, which may be, for example, a Fieldbus interface, a Profibus interface, an AS-Interface, a DeviceNet, a HART interface, a standard 4-20 mA interface, or the like. The controllers 40 are also coupled to one or more host or operator workstations 50, 52 via a communication backbone 54, which may be, for example, an Ethernet link or another suitable local area network (LAN) link. A process data database 58 may be connected to the communication backbone 54 and operates to collect and store parameters, status, and other data associated with the controllers and field devices within the plant 10. During operation of the process plant 10, the process data database 58 may receive process data from the controller 40 and, indirectly, from the devices 44-46 via the communication backbone 54.

[0020] The configuration database 60, once downloaded and stored within the controller 40 and field devices 44 and 46, stores the current configuration of the process control system 22 within the plant 10. The configuration database 60 stores process control functions that define one or more control strategies for the process control system 22, configuration parameters for the devices 44 and 46, assignments of the devices 44 and 46 to process control functions, and other configuration data associated with the process plant 10. In addition, the configuration database 60 may store graphical objects to provide various graphical representations of elements of the process plant 10. Some of the stored graphical objects may correspond to process control functions (e.g., a process graphic developed for a particular PID loop), while other graphical objects may be device-specific (e.g., a graphic corresponding to a pressure sensor).

[0021] The process plant 10 may also include other databases coupled to the communication backbone 54, not shown in FIG. 1 , to avoid clutter. For example, a data historian may store events, alarms, comments, and a history of actions taken by operators. The events, alarms, and comments may relate to individual devices (e.g., valves, transmitters), communication links (e.g., wired Fieldbus segments, Wireless HART communication links), or process control functions (e.g., PI control loops for maintaining desired temperature setpoints). Additionally, a knowledge repository may store references, operator logbook entries, help topics, or links to these and other documents that operators and maintenance technicians may find useful when overseeing the process plant 10. Additionally, a user database may store information about users, such as operators and maintenance technicians. For each user, the user database may store, for example, their organizational role, the area within the process plant 10 to which the user is associated, work team associations, etc.

[0022] Each of these databases may have any desired type of memory and a The databases may be of any desired type, having any desired or known software, hardware, or firmware for storing and managing the data. Of course, the databases need not reside on separate physical devices. Thus, in some embodiments, several of these databases are implemented on a shared data processor. In general, more or fewer databases may be utilized to store the data that is collectively stored and managed by the databases described above.

[0023] While the controllers 40, I / O cards 48, and field devices 44 and 46 are typically distributed throughout a sometimes harsh plant environment, the operator workstations 50 and 52, and databases 58, 60, etc. are usually located in a control room or other less harsh environment where they are easily accessible to controllers, maintenance, and various other plant personnel. In some cases, however, handheld devices may be used to perform these functions, and these handheld devices are typically transported to various locations within the plant.

[0024] As is well known, each of the controllers 40, which may be, by way of example, the DeltaV™ controller sold by Fisher-Rosemount Systems, Inc., stores and executes a controller application that implements a control strategy using any number of different, independently executing, control modules or blocks 70. Each of the control modules 70 may be generally composed of what are called function blocks, each of which is a portion or subroutine of an overall control routine and operates in conjunction with other function blocks (through communications called links) to implement a process control loop within the process plant 10. As is widely known, a function block, which may be an object in an object-oriented programming protocol, typically performs one of the following physical functions within the process plant 10: an input function, such as one associated with a transmitter, sensor, or other process parameter measurement device; a control function, such as one associated with a control routine that performs control such as PID, fuzzy logic, etc.; or an output function that controls the operation of some device, such as a valve. Of course, hybrid and other types of complex function blocks exist, such as model predictive controllers (MPCs), optimizers, etc. Although the Fieldbus protocol and DeltaV system protocol use control modules and function blocks that are designed and implemented in an object-oriented programming protocol, the control modules may be designed using any desired control programming scheme, including, for example, sequential function blocks, ladder logic, etc., and are not limited to being designed and implemented using function blocks or any other particular programming technique. Each of the controllers 40 may also support the application AMS Device Manager, which may use predictive intelligence to improve the availability and performance of production assets, including mechanical equipment, electrical systems, process equipment, instruments, field and smart field devices 44, 46, and valves.

[0025] In the plant 10 illustrated in FIG. 1, the field devices 44 and 46 connected to the controller 40 may be standard 4-20 mA devices, or may be smart field devices including a processor and memory, such as HART, Profibus, ASibus, DeviceNet, or FOUNDATION™ Fieldbus field devices, or any other desired type of device. Some of these devices, such as the Fieldbus field device (annotated with reference numeral 46 in FIG. 1), may store and execute modules or sub-modules, such as function blocks associated with the control strategy implemented in the controller 40. A function block 72, illustrated in FIG. 1 as being disposed in one of the Fieldbus field devices 46, may be a control module within the controller 40, as is commonly known. 7. The I / O cards 48 may be implemented in conjunction with the execution of the system controller 70 to implement process control. Of course, the field devices 44 and 46 may be any type of device, such as a sensor, a valve, a transmitter, a positioner, etc., and the I / O card 48 may be any type of I / O card that conforms to any desired communication or controller protocol, such as HART, Fieldbus, Profibus, etc.

[0026] The workstations 50 and 52 may include one or more processors 82 that execute instructions stored in memory 80. The instructions may partially implement a viewing application 84 that provides various displays during operation of the process plant 10 to enable the operators 12 to view and control various operations within the process plant 10 or, as is common in larger plants, within the section of the process plant 10 to which the corresponding operator is assigned. The viewing application 84 may include or interface with support applications, such as a control diagnostic application, a tuning application, a report generation application, or any other control support application that may be used to assist the operator in performing a control function. Additionally, the viewing application 84 may enable a maintenance technician to oversee the maintenance needs of the plant 10, for example, to view the operation or operating status of the various devices 40, 44, and 46. The viewing application may also include support applications, such as a maintenance diagnostic application, a calibration application, a vibration analysis application, a report generation application, or other maintenance support application that may be used to assist the maintenance technician in performing maintenance functions within the plant 10.

[0027] 1 , exemplary legacy PLC control system 100 controls field devices within section 120 of process plant 10. Exemplary legacy PLC control system 100 includes a legacy PLC 102, terminal and I / O hardware 104 within a mounting rack / chassis 106, and field devices 110-114 coupled to terminal and I / O hardware 104 by legacy wiring 108. Although FIG. 1 depicts only a single legacy PLC control system 100 within process plant 10, a given process plant may have any number of legacy PLCs controlling corresponding field devices in a portion of the process plant.

[0028] Similarly, FIG. 1 also depicts a retrofit control system 101. The retrofit control system 101 controls field devices in section 121 of the process plant 10 and includes a controller 41 and I / O modules 49 disposed within a mounting rack / chassis 107 that is the same dimensions as the mounting rack / chassis of the retrofitted legacy system (e.g., the same dimensions as mounting rack / chassis 106). The retrofit control system 101 is also disposed within the mounting rack 107 and includes termination hardware 111 and custom interface hardware 113 through which signals from field devices 115-119 are communicated to I / O cards 49 and then to the controller 41. Although FIG. 1 depicts only a single retrofit control system 101 within the process plant 10, a given process plant may have any number of retrofit control systems controlling corresponding field devices in portions of the process plant.

[0029] 2A illustrates an exemplary I / O chassis for a legacy PLC control system, such as the legacy PLC control system 100 depicted in FIG. 1, and in particular illustrates the termination of the mounting rack / chassis 106 and the configuration of the I / O hardware 104. Generally, the mounting rack / chassis 106 is configured to receive signals from the field devices 110-114 controlled by the legacy PLC control system 100 via legacy wiring (shown in FIG. 2B). Legacy wiring is typically organized by I / O type, such as inputs from field devices being grouped together, outputs to field devices being grouped together, etc. Legacy wiring is also typically organized according to signal type, such as analog signal types being grouped together, discrete signal types being grouped together, etc. In some cases, other organization schemes may be used, but typically, signals are grouped such that each set of signals can be communicatively coupled to a single I / O card.

[0030] In contrast, the mounting rack / chassis 106 includes multiple I / O cards 202a-h. Each of the I / O cards 202a-h may be, for example, an analog input card, an analog output card, a discrete input card, a discrete output card, etc. The number and type of I / O cards depend on the number and type of inputs and outputs required for the portion of the process plant controlled by the legacy PLC control system 100. In the embodiment depicted in FIG. 2A , for example, the mounting rack / chassis 106 includes eight I / O cards 202a-h. Additionally, each of the I / O cards 202a-h may be a multi-channel I / O card, as is commonly understood. For example, the I / O cards 202a-h may each be an 8-channel, 16-channel, or 32-channel card that can be coupled to 4, 8, 16, or 32 input or output wires, respectively, of legacy wiring.

[0031] An example of legacy wiring is illustrated in FIG. 2B. A single one of the I / O cards 202 is depicted in FIG. 2B in physical and electrical connection with a swing arm 220 that carries legacy wiring 201. The swing arm 220 depicted in FIG. 2B includes 21 terminals 203, each terminating a wire from legacy wiring 201. The swing arm 220 is depicted attached to a swing arm rod 214, and the swing arm 220 is swingable about the swing arm rod 214, as described below and illustrated in FIG. 3.

[0032] 2A , the I / O cards may be mounted to one or more mounting rails (e.g., DIN rails or any dedicated mounting mechanism) 204 of the mounting rack 106 and are communicatively coupled to a backplane 206, which facilitates communication between the I / O cards 202a-h and remote I / O adapters 208. A power adapter 210 may provide power to the hardware of the mounting rack / chassis 106, including the I / O cards 202a-h and remote I / O adapters 208.

[0033] The remote I / O adapter 208 may generally be responsible for routing signals between the various I / O cards 202a-h and the legacy PLC 102. That is, the remote I / O adapter 208 may receive the various output signals from the legacy PLC 102 intended for the field devices 110-114 and, where appropriate, route the signals to the various I / O cards 202a-h so that each signal reaches the appropriate device. Similarly, the remote I / O adapter 208 may receive signals from the I / O cards 202a-h and communicate the signals to the legacy PLC 102.

[0034] A backplane 206 and / or a communication link (e.g., an Ethernet connection, an RS-232 / 485 connection, a proprietary protocol, etc.) 212 may provide communication between the remote I / O adapter 208 and the older PLC 102. In some cases, the older PLC 102 may be located remotely from the mounting rack / chassis 106. Thus, the communication link 212 may communicatively couple the older PLC 102 directly to the remote I / O adapter 208, or in an alternative embodiment, the communication link 212 may communicatively couple the older PLC 102 to a port (not shown) on the backplane 206, which may provide a communication link to the remote I / O adapter 208 and, in turn, to the I / O cards 202a-h.

[0035] In embodiments, particularly the embodiment depicted in FIG. 2A, the mounting rack / chassis 106 includes a cylindrical swing arm rod 214 that functions as an axis, and as will become apparent with reference to FIG. 3, a plurality of swing arms (not depicted in FIG. 2A, but one of which is depicted in FIG. 2B) can pivot about the cylindrical swing arm rod 214 to selectively couple or decouple the I / O cards 202a-h from the legacy wiring via connectors 216a-h on the I / O cards 202a-h and corresponding connectors on the swing arms.

[0036] Figure 3 illustrates a side view (from direction A as depicted in Figure 2A) of the mounting rack / chassis 106, depicting from the side the arrangement of a single one 202 of the I / O cards 202a-h within the mounting rack / chassis 106. Also depicted in the side view of Figure 3 is a swing arm 220. The swing arm 220 has an opening 222 or arcuate clip 223 (see Figure 4) sized to receive the swing arm rod 214 such that the swing arm 220 rotates about the swing arm rod 214 with little or no non-rotational movement. That is, swing arm 220 cooperates with swing arm rod 214 to allow swing arm 220 to move toward and away from I / O card 202 with little or no movement of swing arm 220 along the length of swing arm rod 214 and with little or no space between the inner surface of opening 222 (or clip 223) and the outer surface of swing arm rod 214. While FIG. 3 depicts only a single swing arm 220, it should be understood that mounting rack / chassis 106, and particularly swing arm rod 214, may carry multiple swing arms 220, and specifically, one swing arm 220 for each of multiple I / O cards 202 (e.g., one swing arm for each of I / O cards 202a-h). Advantageously, in embodiments using a swing arm with clips 223 (as depicted in FIG. 4), the swing arm 220 can be removed from the swing arm rod 214 to facilitate access to the remaining hardware of the mounting rack / chassis 106.

[0037] The swing arm 220 in FIG. 3 is depicted as having a connector 224 that corresponds to the connector 216 on the I / O card 202. The connector 224 is disposed on the swing arm 220 such that when the swing arm 220 rotates about the swing arm rod 214, the connector 224 on the swing arm 220 aligns with the connector 216 on the I / O card 202 when the two connectors 216, 224 make contact. The connectors 216, 224, respectively, may be the male and female sides of any type of connector known in the art and suitable for carrying signals of the type communicated between the I / O card 202 and the field devices 110-114 (or vice versa). Thus, while not typical, the connectors 216, 224 used for each swing arm 220 may vary depending on the type of signals carried by the wiring coupled to the swing arm 220 and to the connectors 224, 216. Connectors 216, 224 may be, by way of example, contact-type connectors (also known as "tulip" connectors), card edge connectors, or the like.

[0038] Each of the swing arms 220 can be any type of swing arm commonly known and / or used in the process control art. By way of example, FIG. 5 shows a plurality of swing arms 230-234 (viewed from direction B as depicted in FIG. 3) having different numbers of terminals to which legacy wiring from field devices can be terminated. The swing arms 230-234 have 10, 10, 18, 21, and 40 terminals, respectively. While the depicted swing arms 230-234 use screw-type terminals (i.e., contacts where the ends of bare or stranded wires are placed under a screw and the screw is tightened to bring the wire ends into contact with metal contacts), other embodiments may use other types of terminals, but still connect the wires carrying signals to / from the field devices to their corresponding terminals on the connector 224. The electrical contacts function to create and maintain an electrical connection between the electrical contacts.

[0039] FIG. 6 shows multiple swing arms with wires terminated to the multiple swing arms.

[0040] Referring now to Figure 7, there is shown a block diagram of an exemplary I / O rack for a retrofit control system, such as the retrofit control system 101 depicted in Figure 1. Specifically, Figure 7 illustrates the configuration of hardware within a mounting rack 107. The mounting rack may have the same or approximately the same dimensions as the mounting rack / chassis 106 of the legacy PLC control system 100, such that the mounting rack 107 may be substituted for the mounting rack / chassis 106 during the retrofit / upgrade process.

[0041] Generally speaking, the mounting rack 107 includes hardware for coupling legacy wiring on the swing arms 220 (or other legacy wiring mechanisms) present in the legacy PLC-based system being retrofitted to a non-PLC-based distributed process controller. For example, for every swing arm 220, the mounting rack 107 includes a corresponding piece of hardware (through other hardware) that communicatively couples a connector (e.g., connector 224) on the swing arm 220 to the distributed process controller. For example, if the swing arm 220 is fitted with a "male" card edge connector, the corresponding piece of hardware to which the swing arm 220 connects in the mounting rack 107 will have a corresponding connector, such that the corresponding piece of hardware includes a "female" card edge connector. Of course, the mounting rack 107 also includes a swing arm rod 214 in embodiments using swing arms.

[0042] The mounting rack 107 also typically includes I / O cards that are compatible with the distributed process controller, as described below, and typically replace one or more I / O cards in older PLC-based systems.

[0043] 7, mounting rack 107 includes a plurality of custom interface modules 113a-h. Each custom interface module 113a-h has a connector disposed on its front (i.e., outward-facing) surface that corresponds to the swing arm or other legacy wiring mechanism to which the connector is expected to mate. Thus, for a mounting rack 107 configured to replace the mounting rack 106 described above, the connectors on custom interface modules 113a-h will be the same connectors 216a-h present on I / O cards 202a-h. Of course, it should be understood that connectors 216a-h on custom interface modules 113a-h need only be identical to connectors 216a-h on I / O cards 202a-h, and, as will be apparent, need not be removed from I / O cards 202a-h to accommodate custom interface modules 216a-h. Connectors 216a-h on custom interface modules 113a-h are arranged such that when swing arm 220 rotates about swing arm rod 214, connector 224 electrically and mechanically couples to a corresponding connector 216 present on the custom interface module.

[0044] As mentioned above, the legacy wiring may be stiff and / or brittle due to age and environmental conditions, and therefore it may be desirable to limit movement of the legacy wiring while performing the retrofit, and / or it may be impossible to move the wiring significantly. Accordingly, the custom interface module may be disposed in the mounting rack 107 so that it has a small lateral offset from the corresponding position of the I / O card 202 that it replaces, but that offset is limited by the ability of the legacy wiring mechanism to accommodate the offset, for example, by slight movement along the swing arm rod 214 of the swing arm 220.

[0045] Each of the custom interface modules 113a-h is communicatively coupled to one or more I / O cards 49a-h. The I / O cards 49a-h are preferably standard I / O cards used in distributed process controller-based systems, and as described in more detail below, the custom interface modules 113a-h condition signals between the I / O cards 49a-h and legacy wiring leading to the field devices 115-119. The I / O cards 49a-h may be communicatively and physically coupled to an I / O card carrier 252. Generally, the I / O carrier 252 is configured to accept some number of I / O cards 49. In various embodiments, for example, the I / O carrier 252 is configured as a 2-wide, 4-wide, 6-wide, or 8-wide I / O carrier 252, capable of carrying and interacting with at most two, four, six, or eight I / O cards 49, respectively. 7 would necessarily include 8-wide I / O carriers 252. In any event, the I / O carriers 252, in addition to carrying signals from multiple I / O cards 49 to the controller module 250, also provide power to the I / O cards 49 (in an embodiment, from an external power source).

[0046] In an embodiment, the mounting rack 107 also includes a distributed process controller (e.g., process controller 41 depicted in FIG. 1). FIG. 7 depicts two redundant distributed process controllers 41a and 41b, each controlling a set of communication ports (e.g., Ethernet ports) 246a and 246b, respectively, and associated power modules 244a and 244b. As depicted in FIG. 7, the controllers 41a, 41b, power modules 244a, 244b, and communication ports 246a, 246b may all be part of a controller module 250. The controller module 250 may be coupled to I / O cards via a backplane / carrier (not shown) or by any other known method.

[0047] While FIG. 7 is depicted as having eight I / O cards 49a-49h, it should be understood that the number of I / O cards may depend on the number of I / O channels required and / or the presence of legacy wiring mechanisms (corresponding to the number of custom interface modules). FIG. 7 illustrates eight custom interface modules 113a-h and eight corresponding I / O cards 49a-h, implying that each of the I / O cards 49a-h is associated with a corresponding one of the custom interface modules 113a-h and therefore has the same (or greater) number of channels as the number of inputs or outputs of the legacy wiring mechanisms (e.g., swing arm 220) coupled to the custom interface module. However, while in some embodiments each of the custom interface modules may be associated with a corresponding one of the I / O cards, in other embodiments a single I / O card may be associated with (and communicatively coupled to) two or more custom interface modules, as will become clearer, for example, with respect to FIGS. 9-12.

[0048] The relationship between components within the mounting rack may be more easily visualized with reference to FIG. 8, which illustrates a view of the mounting rack 107 from direction "C" in FIG. 7. In an embodiment, I / O carriers 252 are mounted to the mounting rack 107 using a mounting mechanism such as DIN rails 204. I / O cards 49 are physically and electrically coupled to the I / O carrier cards 252. Each of the I / O cards 49 may have any standard (or non-standard) channels for receiving or transmitting any corresponding number of signals. Typical I / O cards have 8, 16, or 32 channels per I / O card 49. Thus, depending on the number of channels present in the legacy wiring connection mechanism (e.g., swing arms 220), a single one of the I / O cards 49 may be capable of corresponding to channels associated with one, two, or more swing arms 220. For example, each swing arm If the arms 220 carry 16 channels and each I / O card 49 is a 32 channel I / O card, then each I / O card 49 can accommodate the signals of two swing arms 220 .

[0049] As can be appreciated, in some embodiments, there must be a mechanism for communicatively coupling signals from two swing arms 220 to a single one of the I / O cards 49. Each swing arm 220 couples signals on the legacy wiring via connectors 224 and 216 to a custom interface module 113 configured to accept signals on that legacy wiring. Thus, in such embodiments, it may be desirable to communicatively couple multiple custom interface modules 113 to a single I / O card 49. Accordingly, in embodiments, I / O carrier 252 is also configured with one or more associated I / O aggregation connection terminal blocks 254. I / O terminal blocks 254 provide a standardized interface between I / O cards 49 and custom interface modules 113, which, as discussed above, may vary depending on the type of connector 216, the type of signals being carried to / from I / O cards 49, the number of channels on each custom interface module 113, etc. Each custom interface module 113 may be communicatively coupled to an I / O terminal block, which in turn communicates signals processed by the custom interface module 113 to an associated I / O card 49 .

[0050] With this goal in mind, in embodiments, I / O terminal block 254 has one or more connectors 256 disposed thereon that facilitate a communicative coupling between I / O terminal block 254 and custom interface module 113. Similarly, custom interface module 113 has a corresponding connector 258 disposed thereon. For example, the I / O terminal block 254 depicted in FIG. 8 includes two such connectors 256a and 256b, such that I / O terminal block 254 can provide communication from two custom interface modules 113 to a single I / O card 49, allowing, for example, a single 32-channel I / O card to handle signals processed in a PLC-based system by two 16-channel I / O cards. While any suitable wiring can be used between connector 258 on custom interface module 113 and connector 256 on I / O terminal block 254, in embodiments, a ribbon cable connector 260 is used. Due to the compact nature of the installation, in embodiments it may be desirable to use short lengths of coiled ribbon connectors and longer lengths of standard ribbon cable outside of the I / O mounting rack 107.

[0051] 8 also illustrates custom interface module 113 having a form factor that allows custom interface module 113 to fit into mounting rack 107 in a manner that does not prevent removal of I / O card 49, for example, for replacement or other maintenance purposes. Additionally, in embodiments, I / O card 49 may also be removable without disconnecting swing arm 220 from custom interface module 113.

[0052] 7, while each of custom interface modules 113a-h is depicted as having a width approximately equal to the width of I / O cards 49a-h, it should be understood that custom interface modules 113a-h may be narrower or wider than I / O cards 49a-h in various embodiments. The only requirement is that the width of custom interface modules 113a-h of I / O cards 202a-h (see FIG. 2A) does not exceed pitch P (i.e., the spacing between corresponding edges of two adjacent cards). That is, custom interface modules 113a-h are positioned within mounting rack 107 to match the position of swing arm 220. It must be possible.

[0053] In some embodiments, the mounting rack / chassis 106 being replaced by the mounting rack 107 includes I / O cards 202 along its entire width, and therefore the retrofit mounting rack 107 would similarly require I / O cards 113 across its entire width, such that each of the existing swing arms 220 has a corresponding I / O card 113. FIG. 9 illustrates one such embodiment. In FIG. 9, the retrofit mounting rack 300 is configured to replace a legacy PLC rack (not shown), with 12 legacy I / O cards (not shown), each connected to a corresponding swing arm (not shown), occupying the entire width of the corresponding mounting rack (not shown). As a result, the mounting rack 300 includes 12 custom interface modules 302a-l. However, in the embodiment depicted in FIG. 9, the I / O cards 304a-f can each accommodate signals from two of the custom interface modules, and therefore only one I / O card 304a-f is required for every two custom interface modules 302a-l. Custom interface modules 302a-b, for example, may be communicatively coupled to I / O card 304a, custom interface modules 302c-d may be coupled to I / O card 304b, etc. Of course, each I / O card 304a-f is communicatively coupled to a custom interface module 302a-l that is adjacent to each other or to the I / O card 302a-f to which it is coupled. As a result, I / O carrier 252 is populated with only six I / O cards (i.e., I / O cards 304a-f), leaving two empty positions 312 with no I / O cards present.

[0054] In embodiments such as that depicted in FIG. 9 , where the custom interface modules 302a-l occupy most or all of the width of the mounting rack 300, there may be insufficient space for the controller module assembly. Thus, in some embodiments, the controller module 250 may be positioned outside and / or remotely from the mounting rack 300. Alternatively, the carrier extender module 310 may be mounted to (or immediately adjacent to) the mounting rack 300. The carrier extender module 310 may be communicatively coupled to the I / O carrier 252 to facilitate communication of signals between the I / O cards 304a-f and the controller module 250. While the carrier extender module 310 may be communicatively coupled to the controller module 250 by any communication medium, in some embodiments, communication cable(s) are used between the controller module 250 and the carrier extender module 310.

[0055] FIG. 10 illustrates another embodiment. In FIG. 10, a mounting rack 320 includes a controller module 250, an 8-wide I / O card carrier 252, and eight custom interface modules 322a-h. The I / O carrier 252 houses four I / O cards 324a-d, each communicatively coupled to a respective pair of custom interface modules 322a-h. (The I / O cards may each be a 32-channel I / O card and a custom interface module coupled to a swing arm carrying 16 channels, or the I / O cards may each be a 16-channel I / O card and a custom interface module coupled to a swing arm carrying 8 channels, etc.) Thus, because only four I / O cards 324a-d are needed in the depicted embodiment, the 8-wide I / O card carrier 252 has four empty positions 312 in FIG. 10.

[0056] Often in process control systems, legacy wiring runs into multiple racks that may be located adjacent to one another, for example, one above the other or one to the other. In such cases, see Figure 11 and Yet another embodiment of a retrofit solution is contemplated, as depicted in FIGS. 11 and 12 . FIGS. 11 and 12 show two retrofit mounting racks 400 and 402 that are to replace two similarly arranged older mounting racks (not shown). As in the previous embodiment, mounting rack 400 includes an 8-wide I / O carrier 406a that houses eight I / O cards 408a-h. Two additional I / O cards 408i-j house a second 4-wide I / O carrier 406b, providing a total of ten I / O cards 408a-j. Mounting rack 400 also includes ten custom interface modules 412a-j, each communicatively coupled to one of the I / O cards 408a-j. Finally, mounting rack 400 includes a carrier extender 410 configured to be communicatively coupled to a controller module (not shown), such as controller module 250 depicted with respect to FIG. 7 . Together, mounting rack 402 includes ten custom interface modules 414a-j. Each of custom interface modules 414a-j is communicatively coupled to one of I / O cards 408a-j in mounting rack 400. (In this embodiment, each of I / O cards 408a-j may have twice as many channels as each of custom interface modules 414a-j.)

[0057] Referring to FIG. 12, which depicts mounting racks 400 and 402 as viewed from direction "D" in FIG. 11, showing right-most components 412a, 414a, 408a, etc., custom interface modules 412a-j and 414a-j each have a respective connector 418a-j or 420a-j. Similarly, I / O terminal blocks 416a-j each have a pair of connectors 422a, 422b. Connectors 418a-j and 420a-j facilitate the communicative coupling of signals of custom interface modules 412a-j and 414a-j, respectively, with I / O terminal blocks 416a-j. FIG. 12 depicts both custom interface modules 412a and 414a communicatively coupled to I / O terminal block 416a-j associated with I / O card 408a by wires (e.g., ribbon cables) 424a and 426a, respectively. In the illustrated embodiment, both custom interface modules 412b and 414b would each be communicatively coupled by wiring (e.g., ribbon cables) to an I / O terminal block associated with I / O card 408b, etc. However, as noted above, custom interface modules 412a-j and 414a-j need not be communicatively coupled to I / O cards 408a-j in any particular manner. The particular custom interface module coupled to a particular I / O card may be selected according to the type of signal, the configuration of the control system, the physical layout of the process plant, or any other suitable criteria.

[0058] The embodiments described herein provide a solution for retrofitting older PLC-based systems that change only in a few predictable ways with each retrofit.

[0059] Mounting Rack Dimensions: The mounting racks / chassis 106 for legacy PLC-based systems generally come in handy dimensions for each PLC manufacturer and type. For example, for a particular PLC manufacturer, the mounting racks / chassis 106 for legacy systems may be available in 4-, 8-, 12-, and 16-card racks, each with a predetermined height, width, and depth. Each mounting rack also has a predetermined card pitch (the distance between the same point on two adjacent cards).

[0060] Number of channels per I / O card: Each I / O card in a legacy mounting rack typically has one of several numbers of channels. For example, legacy I / O cards often have 4, 6, 8, 16, or 32 channels.

[0061] Type of legacy wiring mechanism: Swing arms are typical, but some legacy systems or installations may use other connector mechanisms. When swing arms are used, they provide different form factors and different numbers of terminations (the different number of terminations generally relates to the number of channels on the legacy I / O card).

[0062] Connector Types for Connecting Older Wiring Mechanisms to Older I / O Cards: As mentioned above, a variety of connectors exist for connecting wiring mechanisms to older I / O cards. Typical examples of connectors include card edge connectors and contact ("tulip") connectors, and each manufacturer typically uses only one or two different types of connectors.

[0063] Vertical position of the connector in the mounting rack: This is commonly associated with older I / O card designs and swing arm types.

[0064] Once the details of the older PLC-based system are known, a retrofit (i.e., replacement) mounting rack can be assembled according to the parameters of the older system. The dimensions of the retrofit mounting rack can be selected, and the retrofit mounting rack can be populated with enough I / O carriers or carriers to carry the number of I / O cards needed to support the number of I / O cards on the older system. For example, if the older system contained sixteen 16-channel I / O cards in a single rack, the retrofit mounting rack can include eight 8-wide I / O carriers populated with eight 32-channel I / O cards, and sixteen custom interface modules (one for each older wiring mechanism).

[0065] FIG. 13 illustrates a generic custom interface module 450 having an I / O card connector 452, a legacy wiring connector 454, and a signal conditioning module 456. The I / O card connector 452 is electrically connected to the signal conditioning module 456, which in turn is electrically connected to the legacy wiring connector 454. Although not depicted in FIG. 13 , the custom interface module 450 may also include a current-limiting circuit and / or a protective fuse(s). As understood herein, the legacy I / O card type determines the type of legacy wiring connector 454, the location of the legacy wiring connector 454 along the dimension “H” within the mounting rack, the number of channels, the card type (input or output), and the type of electrical signal; however, there is a one-to-one correspondence between the legacy I / O card type and the custom interface module, while all of the remaining components of the retrofit mounting system (controller or carrier extender, I / O cards, I / O carriers, and I / O terminal blocks) can remain the same (only the number and size of I / O carriers and the number of I / O cards change). Additionally, because some legacy I / O cards may differ only in the type (AC, DC, various voltages, etc.) and / or direction (input or output) of the signals they carry, the custom interface modules corresponding to those legacy I / O cards need only differ by signal conditioning module 456. Thus, in an embodiment, signal conditioning module 456 may be removable and replaceable on custom interface module 450 (without having to manufacture a different one for each signal type) to minimize the number of custom interface module types that must be manufactured. Of course, signal conditioning module 456 may even be a module or a set of separate components permanently located on custom interface module 450.

[0066] In an embodiment, because the I / O cards used in a retrofit installation rack are always the same, the I / O card side of signal conditioning module 456 (i.e., the side that couples to connector 452) is always the same type of signal. For example, an individual I / O card may be configured to receive and transmit a 24VDC signal, and thus signal conditioning module 456 may be configured to receive and transmit a 24VDC signal. 56 will always output a 24 VDC signal to connector 452 for input-type custom interface modules and will always receive a 24 VDC signal from connector 452 for output-type custom interface modules. As a result, only a limited number of variations of signal conditioning module 456 are required. In fact, there will be an input-type signal conditioning module 456 and an output-type signal conditioning module 456 for each signal type that may be present on connector 454. Typical analog signals include 120 VDC, 120 VAC, 24 VAC, 48 VAC, 60 VAC, 27 VAC, 48 VDC, 220-240 VDC, and 220-240 VAC, as well as relay contacts, while typical analog signals include 0-10 VDC, 0-5 VDC, 1-5 VDC, -10-10 VDC, 4-20 mA, and 4-20 mA HART. Each discrete signal, and most analog signals, will require two variations of the signal conditioning module: an input and an output. Additionally, 24VDC signals and some analog signals may not require signal conditioning and therefore can be accommodated by a pass-through type signal conditioning module.

[0067] Preferably, in an embodiment, custom interface module 450 is designed to facilitate the airflow necessary to cool the I / O cards positioned above the custom interface module in a mounting rack. Specifically, custom interface module 450 may be designed to facilitate airflow (e.g., by convection) from the bottom of custom interface module 450 to the top of custom interface module 450 and through the I / O cards positioned above the custom interface module.

[0068] A method 500 for upgrading a portion of a process control system from a legacy PLC-based system to a non-PLC process controller-based system will now be described with respect to Figure 14. The method 500 includes assembling a mounting rack (block 502). In some embodiments, assembling the mounting rack may require receiving information about the legacy PLC-based system, including, by way of example and not limitation, the type of PLC-based system, the manufacturer of the PLC-based system, the number of I / O cards, the type of connectors used between the legacy wiring and the I / O cards, and the type of signals communicated to and from each I / O card.

[0069] Once the mounting rack is assembled, replacement hardware is installed in the mounting rack (block 504). The replacement hardware may include a non-PLC process controller or a carrier extender configured to be communicatively coupled to the non-PLC process controller. The replacement hardware may also include I / O cards, I / O terminal blocks, and custom interface modules coupled to the non-PLC process controller or carrier extender.

[0070] Once the mounting rack is assembled and installed, the legacy cabling(s) (e.g., swing arm(s)) are disconnected from the legacy hardware associated with the PLC (e.g., from the legacy I / O cards) (block 506). The legacy cabling(s) may be pivoted away from the legacy I / O cards (in the case of swing arms) or, in some cases, detached from the swing arm rod on which the swing arm rod pivots to provide greater accessibility to the legacy hardware and facilitate its removal. The legacy hardware associated with the PLC is removed (block 508) without disrupting the legacy cabling (and attached legacy wiring), but without removing the legacy wiring from the legacy cabling. The removed hardware may include the legacy I / O cards, the rack in which they are mounted, and, in embodiments, power and / or communication hardware that communicates signals from the I / O cards to the PLC.

[0071] The assembled retrofit mounting rack is placed in the space previously occupied by the removed hardware (block 510), after which the old cabling is physically and electrically coupled to the replacement hardware, i.e., the custom interface modules (block 512).

[0072] The following list of aspects reflects various embodiments expressly contemplated by the present application. Those skilled in the art will readily appreciate that the following aspects are exemplary in nature, and are not intended to limit the embodiments disclosed herein, nor are they intended to be exhaustive of all embodiments contemplated in light of the above disclosure.

[0073] 1. A method for upgrading a process control system from an older programmable logic controller (PLC) to a non-PLC process controller, the method comprising assembling a mounting rack, the mounting rack being sized and configured to fit into a space occupied by a rack housing older hardware associated with the older PLC; and introducing replacement hardware into the mounting rack, the replacement hardware comprising: a non-PLC process controller or a carrier extender configured to be communicatively coupled to the non-PLC process controller; input / output (I / O) cards communicatively coupled to the non-PLC process controller or the carrier extender in the mounting rack; I / O cards communicatively coupled to the I / O cards and / or to communicate to the I / O cards signals corresponding to a plurality of process control field devices. and a custom interface module communicatively coupled to (i) the I / O card via the I / O terminal block and (ii) the plurality of process control field devices via a legacy wiring mechanism coupled to legacy wiring of the process control system without requiring modification or re-termination of the legacy wiring; disconnecting the legacy wiring mechanism from legacy hardware associated with the PLC; removing a rack housing the legacy hardware associated with the legacy PLC; placing an assembled mounting rack including replacement hardware in the space previously occupied by the rack housing the legacy hardware associated with the legacy PLC; and coupling the legacy wiring mechanism to the custom interface module.

[0074] 2. The method of aspect 1, wherein the replacement hardware includes a non-PLC process controller.

[0075] 3. The method of aspect 1, wherein the replacement hardware includes a carrier extender configured to be communicatively coupled to the non-PLC process controller.

[0076] 4. The method of any one of aspects 1-3, wherein the replacement hardware includes a plurality of custom interface modules for coupling to a corresponding plurality of legacy wiring mechanisms.

[0077] 5. The method of aspect 4, wherein the replacement hardware includes an equal number of I / O cards and custom interface modules, each I / O card communicatively coupled to one of the plurality of custom interface modules.

[0078] 6. The method of aspect 4, wherein the replacement hardware includes half the number of I / O cards as custom interface modules, each I / O card communicatively coupled to a pair of multiple custom interface modules.

[0079] 7. The method of any one of aspects 1-6, wherein the custom interface module conditions signals communicated between the process control device and the I / O card to be compatible with the I / O card.

[0080] 8. The method of any one of aspects 1-7, wherein the legacy hardware associated with the legacy PLC includes a legacy I / O card.

[0081] 9. The method of any one of aspects 1-8, wherein the legacy wiring is terminated in a swing arm.

[0082] 10. The method of any one of aspects 1-9, wherein the I / O terminal block is coupled to the custom interface module via a ribbon cable.

[0083] 11. The method of embodiment 10, wherein the ribbon cable is a self-winding ribbon cable.

[0084] 12. The method of any one of aspects 1-11, wherein the I / O card is removable after upgrading the process control system to a non-PLC process controller without disconnecting the old wiring mechanism from the custom interface module.

[0085] 13. The method of any one of aspects 1-12, further comprising receiving one or more parameters specifying one or more aspects of the mounting rack and the custom interface module prior to assembling the mounting rack and prior to deploying the mounting rack.

[0086] 14. The method of embodiment 13, further comprising determining from one or more parameters specifying one or more aspects of the mounting rack and the custom interface module one or more of: (i) a type, input, or output associated with the custom interface module; (ii) a voltage received from or transmitted in the legacy wiring; (iii) a contact type coupling the legacy wiring mechanism to the custom interface module; (iv) a width, height, and / or depth of the mounting rack; (v) a number of I / O cards and / or I / O terminal blocks to install in the mounting rack; and / or (vi) a number of custom interface modules to install in the mounting rack.

[0087] 15. The method of any one of aspects 1-14, wherein the custom interface module is a pass-through module.

[0088] 16. The method of any one of aspects 1-15, wherein the components used to upgrade the first older PLC type differ from the components used to upgrade the second older PLC type only by a mounting rack and a custom interface module.

[0089] 17. The method of any one of aspects 1-16, wherein installing the replacement hardware in the mounting rack includes installing a plurality of custom interface modules in the mounting rack, each of the plurality of custom interface modules positioned to couple to a corresponding legacy wiring mechanism.

[0090] 18. A custom interface module, and a legacy wiring link configured to mechanically and electrically link the custom interface module to a mating legacy wiring link, the mating legacy wiring link being for carrying a plurality of signals to or from a plurality of process control field devices. a legacy wiring connection mechanism that terminates legacy wiring of the I / O card to a mating legacy wiring connection mechanism; an I / O coupling mechanism configured to facilitate electrical coupling of the custom interface module to the I / O card such that, for each of a plurality of signals, a corresponding signal is communicated to or from the I / O card via the I / O card; and an adjustment module electrically disposed between the I / O coupling mechanism and the legacy wiring connection mechanism, the adjustment module configured to, for each of the plurality of signals, (i) convert a signal received at the legacy wiring connection mechanism into a signal that can be transmitted to the I / O card via the I / O coupling mechanism, or (ii) convert a signal received from the I / O card via the I / O coupling mechanism into a signal that can be transmitted to a corresponding process control field device via the legacy wiring connection mechanism.

[0091] 19. The custom interface module of embodiment 18, wherein the mating wiring connection mechanism is disposed on a swing arm.

[0092] 20. The custom interface module of one of embodiments 18 or 19, wherein the I / O coupling mechanism is configured to receive a ribbon cable connector.

[0093] 21. The custom interface module of any one of aspects 18-20, wherein the signal passing through the I / O linkage is a 24 VDC signal.

[0094] 22. The custom interface module of any one of aspects 18-20, wherein the signal passing through the I / O coupling is a 4-20 mA signal.

[0095] 23. The custom interface module of any one of aspects 18-20, wherein the signals passing through the legacy hardwired mechanism are 120VDC, 60VAC, 27VAC, 48VDC, 240VAC, 240VDC.

[0096] 24. The custom interface module of any one of aspects 18-23, further comprising a current limiting circuit.

[0097] 25. The custom interface module of any one of aspects 18-24, further comprising an arrangement of components configured to promote airflow between the custom interface module and the I / O card.

[0098] 26. The custom interface module of any one of aspects 18-25, wherein the legacy wiring connection mechanism is a card edge connector.

[0099] 27. A system for upgrading a process control system from a legacy programmable logic controller (PLC) to a non-PLC process controller, the system comprising: a mounting rack sized and configured to fit into a space occupied by legacy hardware associated with the legacy PLC; a non-PLC process controller; an input / output (I / O) card coupled to the non-PLC process controller and mounted in the mounting rack; an I / O terminal block communicatively coupled to the I / O card and configured to pass I / O card signals to and / or transmit I / O card signals to a plurality of process control field devices, the I / O terminal block mounted in the mounting rack; and a custom interface module mounted in the mounting rack and communicatively coupled (i) to the I / O card via the I / O terminal block, and (ii) to the plurality of process control field devices via a legacy wiring mechanism coupled to the legacy wiring of the process control system, without requiring modification or re-termination of the legacy wiring.

[0100] 28. The system of aspect 27, wherein the non-PLC process controller is mounted on a mounting rack.

[0101] 29. The system of aspect 27, wherein a carrier extender is mounted to the mounting rack and communicatively coupled to the non-PLC process controller, and the carrier extender is communicatively coupled to the I / O card to facilitate communication between the I / O card and the non-PLC process controller.

[0102] 30. The system of any one of aspects 27-29, wherein the plurality of custom interface modules are mounted in a mounting rack and are for coupling to a corresponding plurality of legacy wiring mechanisms.

[0103] 31. The system of aspect 30, wherein a number of I / O cards equal to the number of custom interface modules of the plurality of custom interface modules are mounted in the mounting rack, and each I / O card is communicatively coupled to one of the plurality of custom interface modules.

[0104] 32. The system of aspect 30, wherein a number of I / O cards equal to half the number of custom interface modules of the plurality of custom interface modules are mounted in the mounting rack, and each I / O card is communicatively coupled to a pair of the plurality of custom interface modules.

[0105] 33. The system of aspect 30, wherein the system comprises one I / O card for each custom interface module.

[0106] 34. The system of aspect 30, wherein the system comprises one I / O card for every two custom interface modules.

[0107] 35. The system of any one of aspects 27-34, wherein the I / O terminal block is configured to be coupled to two custom interface modules.

[0108] 36. The system of any one of aspects 27-35, wherein each custom interface module is coupled to the I / O terminal block via a ribbon cable.

[0109] 37. The system of any one of aspects 27-36, wherein the custom interface module conditions signals transmitted from the I / O card to be compatible with the field device or conditions signals received from the field device to be compatible with the I / O card.

[0110] 38. The system of any one of aspects 27-37, wherein the legacy hardware associated with the legacy PLC includes a legacy I / O card.

[0111] 39. The system of any one of aspects 27-38, wherein the legacy wiring is terminated at the swing arm.

[0112] 40. The system of any one of aspects 27-39, wherein the I / O terminal block is communicatively coupled to the custom interface module via a ribbon cable.

[0113] 41. The system of embodiment 40, wherein the ribbon cable is a self-winding ribbon cable. .

[0114] 42. The system of any one of aspects 27-41, wherein the I / O card is removable from the mounting rack without disconnecting the legacy cabling from the custom interface module.

[0115] 43. The system of any one of aspects 27-42, wherein the custom interface module is a pass-through module.

[0116] 44. The system of any one of aspects 27-43, wherein the components used to upgrade from a first older PLC type differ from the components used to upgrade from a second older PLC type only by a mounting rack and a custom interface module.

[0117] 45. The system of any one of aspects 27-44, comprising a plurality of custom interface modules each positioned within a mounting rack such that an old-style wiring connection mechanism of a custom interface module is aligned with a mating old-style wiring connection mechanism coupled to the old-style wiring.

Claims

1. 1. A method for upgrading a process control system from legacy programmable logic controllers (legacy PLCs) to non-PLC distributed process controllers, comprising: the legacy PLC is located remotely from a rack housing legacy hardware associated with the legacy PLC; The method comprises: assembling a mounting rack, the mounting rack being sized and configured to fit into the space occupied by the rack housing the legacy hardware associated with the legacy PLC; installing replacement hardware into the mounting rack, the replacement hardware comprising: the non-PLC distributed process controller or a carrier extender configured to be communicatively coupled to the non-PLC distributed process controller and mounted on the mounting rack; an I / O (input / output) card communicatively coupled to the non-PLC distributed process controller or a carrier extender within the mounting rack; an I / O terminal block communicatively coupled to the I / O card and configured to communicate I / O card signals corresponding to a plurality of process control field devices and / or to communicate I / O card signals from the I / O card to a plurality of process control field devices; a custom interface module communicatively coupled to (i) the I / O card via the I / O terminal block and (ii) the plurality of process control field devices via a legacy wiring mechanism coupled to the legacy wiring of the process control system without requiring modification or re-termination of legacy wiring; disconnecting the legacy wiring mechanism from the legacy hardware associated with the legacy PLC while the legacy wiring mechanism remains electrically connected to the plurality of process control field devices; removing the rack containing the legacy hardware associated with the legacy PLC from the space previously occupied by the rack; The assembled mounting rack including the replacement hardware is installed in a location that requires additional space. placing the old hardware associated with the old PLC in the space previously occupied by the rack housing the old hardware without requiring and coupling the legacy wiring mechanism to the custom interface module.

2. 10. The method of claim 1, wherein any one or more of the following is true: (a) the replacement hardware includes the carrier extender configured to be communicatively coupled to the non-PLC distributed process controller; (b) (i) the replacement hardware includes a plurality of custom interface modules for coupling to a corresponding plurality of legacy wiring mechanisms; and (ii) the replacement hardware includes an equal number of I / O cards and custom interface modules, each I / O card communicatively coupled to one of the plurality of custom interface modules; (c) (i) the replacement hardware includes a plurality of custom interface modules for coupling to a corresponding plurality of legacy wiring mechanisms; and (ii) the replacement hardware includes half the number of I / O cards as there are custom interface modules, each I / O card communicatively coupled to a pair of the plurality of custom interface modules; (d) the I / O terminal block is coupled to the custom interface module via a ribbon cable; (e) The custom interface module is a pass-through module.

3. The method of claim 1 , wherein the replacement hardware comprises the carrier extender configured to be communicatively coupled to the non-PLC distributed process controller.

4. The method of claim 1 , wherein the replacement hardware comprises the non-PLC distributed process controller.

5. The method of claim 1 , wherein the replacement hardware includes a plurality of custom interface modules for coupling to a corresponding plurality of legacy wiring mechanisms.

6. The method of claim 1 , wherein the custom interface module conditions the signals communicated between the process control field device and the I / O card to be compatible with the I / O card.

7. The method of claim 1 , wherein the legacy hardware associated with the legacy PLC includes a legacy I / O card.

8. The method of claim 1 , wherein the legacy wiring is terminated in a swing arm.

9. 2. The method of claim 1, wherein the I / O card is removable after upgrading the process control system to the non-PLC distributed process controller without disconnecting the legacy wiring from the custom interface module.

10. 2. The method of claim 1, wherein installing replacement hardware in the mounting rack includes installing a plurality of custom interface modules in the mounting rack, each of the plurality of custom interface modules positioned to couple to a corresponding legacy cabling mechanism.

11. A custom interface module, comprising: a legacy wire connection mechanism configured to mechanically and electrically connect the custom interface module to a mating legacy wire connection mechanism, the mating legacy wire connection mechanism terminating legacy wiring to the mating legacy wire connection mechanism for carrying a plurality of signals to or from a plurality of process control field devices; an I / O coupling mechanism configured to facilitate electrical coupling of the custom interface module to the I / O card such that, for each of the plurality of signals, a corresponding signal is communicated to or from the I / O card via the I / O coupling mechanism; an adjustment module electrically disposed between the I / O coupling mechanism and the legacy wire coupling mechanism, the adjustment module configured to, for each of the plurality of signals, convert a signal received at the legacy wire coupling mechanism into a signal that can be transmitted to an I / O card via the I / O coupling mechanism, or (ii) convert a signal received from the I / O card via the I / O coupling mechanism into a signal that can be transmitted to a corresponding process control field device via the legacy wire coupling mechanism, while a legacy wire coupling mechanism coupled to the legacy wire remains electrically connected to the plurality of process control field devices; the mating old-type wiring connection mechanism is disposed on a swing arm, the old-type wiring connection mechanism is disposed at a position where the old-type wiring connection mechanism can be connected to the mating old-type wiring connection mechanism when the swing arm swings in a direction approaching the custom interface module. Custom interface modules.

12. 12. The custom interface module of claim 11, further comprising a current limiting circuit.

13. 12. The custom interface module of claim 11, further comprising an arrangement of components configured to facilitate airflow between the custom interface module and the I / O card.

14. The custom interface module of claim 11 , wherein the legacy wiring mechanism is a card edge connector.

15. 1. A system for upgrading a process control system from legacy programmable logic controllers (legacy PLCs) to non-PLC distributed process controllers, comprising: the legacy PLC is located remotely from a space occupied by legacy hardware associated with the legacy PLC; The system comprises: a mounting rack sized and configured to fit into the space occupied by the legacy hardware associated with the legacy PLC without requiring additional space; a non-PLC distributed process controller; an I / O (input / output) card coupled to the non-PLC distributed process controller and mounted in the mounting rack; an I / O terminal block communicatively coupled to the I / O card and configured to pass to and / or transmit from the I / O card signals corresponding to a plurality of process control field devices, the I / O terminal block mounted to the mounting rack; Mounted on the mounting rack, no modification or re-termination of old wiring required and (ii) a custom interface module communicatively coupled to the I / O card via the I / O terminal block and to the plurality of process control field devices via a legacy wiring mechanism coupled to the legacy wiring of the process control system.

16. 16. The system of claim 15, wherein any one or more of the following is true: (a) each custom interface module is coupled to said I / O terminal block via a ribbon cable; (b) the custom interface module includes an adjustment module electrically disposed between an I / O coupling mechanism and the legacy wiring mechanism, the adjustment module configured to, for each of a plurality of signals, (i) convert a signal received at the legacy wiring mechanism into a signal that can be transmitted to the I / O card via the I / O coupling mechanism, or (ii) convert a signal received from the I / O card via the I / O coupling mechanism into a signal that can be transmitted to a corresponding process control field device via the legacy wiring mechanism; (c) the custom interface module; a legacy wiring mechanism configured to mechanically and electrically couple the custom interface module to a mating legacy wiring mechanism, the mating legacy wiring mechanism terminating legacy wiring to the mating legacy wiring mechanism for carrying a plurality of signals to or from a plurality of process control field devices; an I / O coupling mechanism configured to facilitate electrical coupling of the custom interface module to the I / O card such that, for each of the plurality of signals, a corresponding signal is communicated to or from the I / O card via the I / O coupling mechanism; an adjustment module electrically disposed between the I / O coupling mechanism and the legacy wiring mechanism, the adjustment module configured to, for each of the plurality of signals, (i) convert a signal received at the legacy wiring mechanism into a signal that can be transmitted to the I / O card via the I / O coupling mechanism, or (ii) convert a signal received from the I / O card via the I / O coupling mechanism into a signal that can be transmitted to a corresponding process control field device via the legacy wiring mechanism; containing, (d) the custom interface module further comprises a current limiting circuit; (e) the custom interface module is a pass-through module; (f) a carrier extender mounted on the mounting rack and communicatively coupled to the non-PLC distributed process controller, the carrier extender communicatively coupled to the I / O card to facilitate communication between the I / O card and the non-PLC distributed process controller.

17. The system of claim 15 , wherein the non-PLC distributed process controllers are mounted on the mounting rack.

18. 16. The system of claim 15, wherein a carrier extender is mounted to the mounting rack and communicatively coupled to the non-PLC distributed process controller, the carrier extender being communicatively coupled to the I / O card to facilitate communication between the I / O card and the non-PLC distributed process controller.

19. a plurality of custom interface modules mounted on the mounting rack; 16. The system of claim 15, wherein the plurality of custom interface modules are for coupling to a corresponding plurality of legacy wiring mechanisms.

20. 20. The system of claim 19, wherein a number of I / O cards equal to half the number of custom interface modules in the plurality of custom interface modules are mounted in the mounting rack, each I / O card being communicatively coupled to a pair of the plurality of custom interface modules.

21. 20. The system of claim 19, wherein the system includes one I / O card for every two custom interface modules.

22. 16. The system of claim 15, wherein each custom interface module is coupled to the I / O terminal block via a ribbon cable.

23. 16. The system of claim 15, wherein the custom interface module conditions signals transmitted from the I / O card to be compatible with the process control field device or conditions signals received from the process control field device to be compatible with the I / O card.

24. The system of claim 15 , wherein the legacy wiring terminates in a swing arm.

25. 16. The system of claim 15, wherein the I / O cards are removable from the mounting rack without disconnecting the legacy cabling from the custom interface modules.

26. 16. The system of claim 15, comprising a plurality of custom interface modules each positioned within the mounting rack such that a legacy wiring connection mechanism of the custom interface module aligns with a mating legacy wiring connection mechanism coupled to the legacy wiring.

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