Abstract:
A handheld field maintenance tool is provided with a removable memory module. The module is preferably adapted to be removable in the presence of a hazardous environment. Further, the handheld field maintenance tool is adapted, via hardware, software, or both to automatically detect the presence of the removable memory module and to copy, or otherwise install, data from the module to the tool. Data can be placed on a removable memory module in any suitable manner including flashing flash memory within the removable memory module, or, in embodiments where the removable memory module includes both storage and input/output capability, transmitting software and/or data to the storage media through the input/output capability.

Description:
[0001]    The present application is a Continuation-In-Part application of U.S. patent application Ser. No. 10/310,703, filed Dec. 5, 2002, entitled INTRINSICALLY SAFE FIELD MAINTENANCE TOOL. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    Intrinsically safe field maintenance tools are known. Such tools are highly useful in the process control and measurement industry to allow operators to conveniently communicate with and/or interrogate field devices in a given process installation. Examples of such process installations include petroleum, pharmaceutical, chemical, pulp and other processing installations. In such installations, the process control and measurement network may include tens or even hundreds of various field devices which periodically require maintenance to ensure that such devices are functioning properly and/or calibrated. Moreover, when one or more errors in the process control and measurement installation is detected, the use of an intrinsically safe hand held field maintenance tool allows technicians to quickly diagnose such errors in the field.  
           [0003]    Intrinsic Safety requirements are intended to guarantee that instrument operation or failure cannot cause ignition if the instrument is properly installed in an environment that contains explosive gasses. This is accomplished by limiting the maximum energy stored in the transmitter in a worst case failure situation. Excessive energy discharge may lead to sparking or excessive heat which could ignite an explosive environment in which the transmitter may be operating.  
           [0004]    Examples of intrinsic safety standards include European CENELEC standards EN50014 and 50020, Factory Mutual Standard FM3610, the Canadian Standard Association, the British Approval Service for Electrical Equipment in Flammable Atmospheres, the Japanese Industrial Standard, and the Standards Association of Australia.  
           [0005]    One intrinsically safe field maintenance tool sold under the trade designation Model 275 HART® Communicator available from Fisher-Rosemount Systems, Inc., of Eden Prairie, Minn. HART® is a registered trademark of the HART® Communication Foundation. The Model 275 provides a host of important functions and capabilities and generally allows highly effective field maintenance. However, the Model 275 does not currently support communication with non-HART® (Highway Addressable Remote Transducer) devices.  
           [0006]    The HART® protocol has a hybrid physical layer consisting of digital communication signals superimposed on the standard 4-20 mA analog signal. The data transmission rate is approximately 1.2 Kbits/SEC. HART® communication is one of the primary communication protocols in process industries.  
           [0007]    Another major process industry communication protocol is known as the FOUNDATION™ fieldbus communication protocol. This protocol is based on an ISA standard (ISA-S50.01-1992, promulgated by the Instrument Society of America in 1992). A practical implementation was specified by the Fieldbus Foundation (FF). FOUNDATION™ Fieldbus is an all-digital communication protocol with a transmission rate of approximately 31.25 Kbits/SEC.  
           [0008]    Known intrinsically safe field maintenance tools are not able to effectively interact using more than one process industry standard protocol. Providing a device that has the ability to operate with more than one process industry standard protocol as well as effectively providing protocol-specific calibration and configuration options would represent a significant advance in the art.  
         SUMMARY OF THE INVENTION  
         [0009]    A handheld field maintenance tool is provided with a removable memory module. The module is adapted to be removable in the presence of a hazardous environment. Further, the handheld field maintenance tool is adapted, via hardware, software, or both to automatically detect the presence of the removable memory module and to copy, or otherwise install, data from the module to the tool. Data can be placed on a removable memory module in any suitable manner including flashing flash memory within the removable memory module, or, in embodiments where the removable memory module includes both storage and input/output capability, transmitting software and/or data to the storage media through the input/output capability. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 illustrates a multidrop wiring configuration.  
         [0011]    [0011]FIGS. 2A and 2B illustrate ways in which an intrinsically safe field maintenance tool may be connected to a process device.  
         [0012]    [0012]FIG. 3 is a diagrammatic view of field maintenance tool in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    An improved intrinsically safe field maintenance tool in accordance with embodiments of the present invention is operable with at least two industry standard device descriptions. In one specific embodiment, an improved intrinsically safe field maintenance tool implements both HART® and fieldbus Device Description Language (DDL). The improved field maintenance tool is used to maintain both two-wire and four-wire (i.e. external power) field devices using these protocols. Preferably, both configuration and calibration are supported via DDL technology. DDL technology is known and additional reading regarding Device Description Language can be found in U.S. Pat. No. 5,960,214 to Sharp, Jr. et al.  
         [0014]    The improved intrinsically safe field maintenance tool also facilitates a convenient display of diagnostic information from individual field devices (i.e. status bits) as well as providing advanced protocol-specific network troubleshooting features. Further details and benefits of the improved intrinsically safe field maintenance tool in accordance with embodiments of the present invention will be appreciated after reading the description below.  
         [0015]    [0015]FIG. 1 illustrates an exemplary system in which embodiments of the present invention are useful. System  10  includes controller  12 , I/O and control sub-system  14 , intrinsic safety (IS) barrier  16 , process communication loop  18  and field devices  20 . Controller  12  is coupled to I/O and control sub-system  14  via link  21  which can be any suitable link such as a local area network (LAN) operating in accordance with Ethernet signaling protocols or any other suitable protocol. I/O and control sub-system  14  is coupled to intrinsic safety barrier  16  which in turn is coupled to process communication loop  18  to allow data communication between loop  18  and I/O and control sub-system  14  in a manner that limits energy passing therethrough.  
         [0016]    In this illustration, process communication or process control loop  18  is a FOUNDATION™ fieldbus process communication loop and is coupled to field devices  20 , which are shown coupled arranged in a multi-drop configuration. An alternative process communication loop (not shown) is an HART® process communication loop. FIG. 1 illustrates a multi-drop wiring configuration that vastly simplifies system wiring compared to other topologies such as the star topology. Multi-drop HART® configurations support a maximum of 15 devices, while multi-drop FOUNDATION™ Fieldbus configurations support a maximum of 32 devices.  
         [0017]    Intrinsically safe field maintenance tool  22  is coupled to loop  18  as illustrated in FIG. 1. When coupled to a process control loop as shown, tool  22  can perform a number of the communication and diagnostic functions. Tool  22  can couple to and interact with HART® process communication loops in much the same way the presently available Model 275 HART® Communicator can.  
         [0018]    [0018]FIG. 2A illustrates tool  22  coupled to HART®-compatible device  20  via terminals  24 . Alternately, tool  22  can communicate with a HART® compatible device on the process instrumentation communication loop, such as device  24  via the loop itself, as indicated in FIG. 2B.  
         [0019]    [0019]FIG. 3 is a diagrammatic view of field maintenance tool  22  in accordance with embodiments of the present invention. As illustrated, tool  22  preferably includes three communication terminals  26 ,  28  and  30  which facilitate coupling tool  22  to process communication loops and/or devices in accordance with at least two process industry standard protocols. For example, when tool  22  is to be coupled to a loop of a first process industry standard protocol, such coupling is effected using terminal  26  and common terminal  28 . Accordingly, the connection then is made via media access unit  32  which is configured to interact upon the process communication loop in accordance with the first industry standard protocol. Additionally, when tool  22  is to be coupled to a process and control measurement loop that operates in accordance with a second industry standard protocol, such connection is made via common terminal  28  and terminal  30 . Thus, such a connection is effected via the second media access unit  34  which is configured to interact upon the process communication loop in accordance with the second industry standard protocol. Both media access units  32  and  34  are coupled to processor  36  which receives data from one of the media access units and interprets that data accordingly.  
         [0020]    Processor  36  is also coupled to keypad module  38  and display module  40 . Keypad module  38  is coupled to the keypad on the housing of tool  22  in order to receive various keypad inputs from a user. Display module  40  is coupled to the display to provide data and/or a user interface.  
         [0021]    In accordance with various embodiments of the present invention, tool  22  includes additional hardware enhancements that facilitate increased functionality over that generally available in the prior art. In one embodiment, tool  22  includes infrared data access port  42  which is coupled to processor  36  to allow tool  22  to transfer information to and from a separate device using infrared wireless communication. One advantageous use of port  42  is for transferring and/or updating Device Descriptions stored in one or more memories of tool  22 . A Device Description (DD) is a software technology used to describe parameters in a field device in a computer-readable format. This contains all of the information necessary for a software application being executed on processor  36  to retrieve and use the parametric data. The separate device such as computer  12 , can obtain a new Device Description from floppy disk, CD ROM, or the internet and wirelessly transfer the new Device Description to tool  22 .  
         [0022]    Tool  22  preferably includes expansion memory module  48  coupled to processor  36  via connector  50  which is preferably disposed on the main board of tool  22 . Expansion memory module  48  may contain Device Descriptions of first and second industry standard protocols. Module  48  may also contain license code(s) that will determine the functionality of tool  22  with respect to the multiple protocols. For example, data residing within module  48  may indicate that tool  22  is only authorized to operate within a single process industry standard mode, such as the HART® protocol. Ultimately, a different setting of that data within module  48  may indicate that tool  22  is authorized to operate in accordance with two or more industry standard protocols. Module  48  is preferably inserted to a connector  50  on the main board and may in fact require partial disassembly of tool  22 , such as removing the battery pack to access port  50 .  
         [0023]    Tool  22  also includes removable memory module  44  which is removably coupled to processor  36  via port/interface  46 . Removable memory module  44  is adapted to store software applications that can be executed instead of primary applications on processor  36 . For example, module  44  may contain applications that use the HART®or FOUNDATION™ fieldbus communication port, to provide a comprehensive diagnostic for a given process device.  
         [0024]    Module  44  may store software applications that aid in the calibration or configuration of specific devices. Module  44  may also store a software image for a new or updated primary device application that can subsequently be transferred into the non-volatile memory of device  36  to enable execution of the updated application. Further still, module  44  provides removable memory storage for the configuration of multiple devices allowing a field maintenance operator to acquire a relatively substantial amount of device data and conveniently store or transfer such data by simply removing module  44 .  
         [0025]    Preferably, the software installable via removable memory module  44  is separately licensable by allowing a field maintenance technician to purchase a license key with the software that is based upon the serial number of removable memory module  44 . Preferably, tool  22  is configured, via hardware, software, or both, to detect when removable memory module  44  is coupled thereto and to automatically recognize the existence of additional software functionality within removable memory module  44 . Once such additional functionality is recognized, the software or other data within module  44  is copied/installed to the random access memory (RAM) of tool  22 . Thereafter, removable memory module  44  can be removed from tool  22  while the benefits of the added software functionality will persist. One form of removable memory module  44  includes commercially available flash memory, or a combination of storage and input/output capability. Essentially, removable memory module  44  includes any suitable storage media which can maintain data therein, and for which the physical package is amendable to the constraints listed below. By using removable memory module  44 , multiple software applications and/or sets of data can be loaded into tool  22  without taking up additional space on the internal flash memory of tool  22 .  
         [0026]    Preferably, module  44  is adapted to be replaceable in hazardous areas in a process plant. Thus, it is preferred that module  44  comply with intrinsic safety requirements set forth in: APPROVAL STANDARD INTRINSICALLY SAFE APPARATUS AND ASSOCIATED APPARATUS FOR USE IN CLASS I, II AND III, DIVISION 1 HAZARDOUS (CLASSIFIED) LOCATIONS, CLASS NUMBER 3610, promulgated by Factory Mutual Research October, 1988. Adaptations to comply with additional industrial standards such as Canadian Standards Association (CSA) and the European CENELEC standards are also contemplated. Examples of specific structural adaptations for memory module  44  and/or interface  46  to facilitate compliance include energy limiting circuits such that the operating voltage level of memory module  44  is sufficiently low that stored energy within module  44  cannot generate a source of ignition.  
         [0027]    Module  44  may include current limiting circuitry to ensure that in the event that specific terminals on module  44  are shorted, that the discharge energy is sufficiently low that ignition is inhibited. Finally, interface  44  may include physical characteristics that are specifically designed to prevent exposure of electrical contacts on memory module  44  to an external environment while simultaneously allowing suitable interface contacts to make electrical contact with module  44 . For example, module  44  may include an overmolding that can be pierced or otherwise displaced by coupling module  44  to interface  46 .  
         [0028]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.