Abstract:
A method for conducting a partial stroke test of an emergency shutdown valve includes receiving a request to initiate the partial stroke test from a user interface or another source, establishing a direct or an indirect wireless communication link with the emergency shutdown valve, and generating one or more commands of a digital industrial automation protocol to be transmitted to the emergency shutdown valve via the wireless communication link, so that a partial stroke test of the emergency shutdown valve is initiated in response to these commands.

Description:
FIELD OF TECHNOLOGY 
       [0001]    The present disclosure relates generally to process control networks and, more particularly, to initiating and monitoring a partial stroke test of an emergency shutdown valve. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Industrial process control systems often include safety instrumented systems (SIS) that generally incorporate an emergency shutdown (ESD) system to transition a shutdown valve to a safe state in the event of a device failure, power failure, or other emergency. A typical ESD system includes a shutdown controller (e.g., a Programmable Logic Controller (PLC), a digital valve controller (DVC), a logic solver) and a solenoid valve to actuate the shutdown valve. In emergencies, the ESD valve transitions to the safe state such as the fully open position or the fully closed position, for example. Usually, however, the ESD shutdown valve remains idle, either permitting a fluid to flow freely through a pipeline, or shutting off all fluid flow through the pipeline. 
         [0003]    To ensure that an ESD valve can function properly, process control system operators periodically test the corresponding ESD system by running a stroke test that partially or completely opens or closes the ESD valve. For simplicity, all such tests are referred to herein as “partial stroke tests,” regardless of whether the ESD valve is closed only partially or completely. Operators often approach ESD valves during partial stroke testing to listen for abnormal sounds, make sure the movement of the actuator appears smooth, and otherwise observe how the valve operates. In some cases, operators also collect data that describes the progress of the partial stroke test (e.g., valve positioning measured at certain times). 
       SUMMARY 
       [0004]    A partial stroke test of an emergency shutdown (ESD) valve is initiated from a device coupled to an ESD system that includes the ESD valve via at least one wireless communication link. In response to receiving a command to initiate a partial stroke test, an ESD system causes the stem of the ESD valve to move to one or several new positions. In some implementations, the ESD system also includes one or several sensors to determine operational parameters of the ESD valve and/or parameters of the environment in which the ESD valve operates (e.g., the flow rate through the ESD valve, fluid pressure upstream of the ESD valve, fluid pressure downstream of the ESD valve, fluid temperature). 
         [0005]    In some embodiments, an operator uses a portable device such as a smartphone, a general-purpose personal digital assistant (PDA), or a portable communicator for use in a process control system to establish a wireless link to the ESD system and transmit one or several commands to the ESD system so as to initiate a partial stroke test. In some embodiments, positioning data and/or other parameters are reported to the portable device via the wireless communication link during the execution of the partial stroke test or following the completion of the partial stroke test. In this manner, the operator can collect historical data as well as create documentation that reflects the history of partial stroke testing. 
         [0006]    The portable device communicates with the ESD system using a general-purpose wireless communication protocol such as Bluetooth, according to some embodiments. The portable device may include software components that layer commands of an industrial automation protocol such as HART™, Profibus®, Foundation Fieldbus™, etc. via the Bluetooth link. The portable device may further include a software system for controlling and diagnosing a valve such as ValveLink™ software, for example. 
         [0007]    In another embodiment, an operator accesses the ESD system via a wireless industrial automation network using a workstation coupled to the industrial automation network. The ESD system in one such embodiment is communicatively coupled to a wireless protocol adapter that enables the ESD system to receive and/or transmit commands of a wireless industrial automation protocol used by the wireless network such as WirelessHART® (ratified by International Electrotechnical Commission as IEC 62591 in April, 2010), for example. 
         [0008]    Depending on the embodiment, the ESD valve is disposed in the same housing as the controller that controls the positioning of the ESD valve to define a common ESD assembly, or in separate housing (coupled to the controller via a wired or wireless communication link). If desired, the ESD assembly may also include position sensors, pressure sensors, temperature sensors, etc. In another embodiment, the ESD system is coupled to one or several sensors disposed outside the ESD assembly. 
         [0009]    In various embodiments, a set of computer-executable instructions for running a partial stroke test is stored on the portable device that communicates with the ESD system via a direct wireless link, a workstation that communicates with the ESD system via one or several wireless links of a wireless communication network, or in the ESD system. For example, in one such embodiment, the controller of the ESD system includes a memory to store a set of instructions for executing a partial stroke test and a processor to execute these instructions in response to a triggering event such as a command received via a wireless communication link. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1A  is a diagram of a known system in which a partial stroke test of an ESD valve is initiated using an operator console coupled to the ESD valve via a wired link. 
           [0011]      FIG. 1B  is a diagram of another known system in which a partial stroke test of ESD valve is initiated from a remote workstation coupled to the ESD valve via a wireless link of a communication network. 
           [0012]      FIG. 2  is a diagram of an example system in which a partial stroke test of an ESD valve is initiated from a portable communicator coupled to the ESD valve via a wireless link. 
           [0013]      FIG. 3  is a diagram of another example system in which a partial stroke test of an ESD valve is initiated from a remote workstation coupled to the ESD valve via a wireless network. 
           [0014]      FIG. 4  is a block diagram of an example portable device that can be used to initiate a partial stroke test in the system depicted in  FIG. 2 . 
           [0015]      FIG. 5  is a flow diagram of an example method for establishing a wireless link between a portable device and an ESD valve to initiate a partial stroke test. 
           [0016]      FIG. 6  is a flow diagram of an example method for wirelessly initiating a partial stroke test of an ESD valve and collecting diagnostic/status data from the ESD valve. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    In various embodiments of the present disclosure, an operator or an automated system initiates a partial stroke test of an ESD valve via a wireless communication link. Accordingly, partial stroke testing can be initiated without providing wired access to the valve or relying on a wired network connection between the valve and a device from which the test is initiated. The operator may also conduct the test after the test has been initiated, if desired. For example, the operator may monitor the progress of the partial stroke using process data reported from the ESD valve via the wireless communication link, control the extent of the test (e.g., the percentage of the maximum open position to which the valve should be moved), temporarily suspend the test, abort the test, etc. In an example implementation, the wireless communication link is a direct wireless link between an ESD system that includes the ESD valve and a portable communication device. The wireless communication link in another example implementation is a part of a wireless communication network, so that the ESD valve and/or the ESD system operates as a wireless network node. 
         [0018]    For clarity, prior to discussing the techniques for wirelessly initiating and/or conducting a partial stroke test of an ESD valve in more detail, several prior art systems are discussed first. Referring to  FIG. 1A , an ESD assembly  10  is coupled to an operator console  12  via a wired link  14 . The ESD assembly  10  includes an ESD valve  20  disposed in a pipeline  24  and controlled by an ESD controller  22 . For example, the ESD controller supplies an electrical or pneumatic signal to actuate a valve stem of the ESD valve  20 , so that the ESD valve  20  opens or closes to the desired percentage. The ESD assembly  10  further includes one or several sensors for measuring operating parameters. In particular, the ESD assembly  10  depicted in  FIG. 1A  includes a flowmeter  26  disposed upstream of the ESD valve  20  and a pressure sensor  28  disposed downstream of the ESD valve  20 . 
         [0019]    The operator console  12  typically includes an input device such as pushbuttons, a keyboard, a mouse, a trackball, etc. and an output device such as a monitor or lights. To initiate a partial stroke test of the ESD valve  20 , an operator physically approaches the operator console  12  and types in (or otherwise enters) commands to interact with the ESD controller  22 . Because operators typically wish to observe the ESD valve  20  during testing, the operator console  12  is disposed close to the ESD controller  22 . Moreover, providing a long wired link between the ESD assembly  10  an the operator console  12  may be expensive and difficult to implement, and thus placing the operator console  12  in a control room remote to the ESD assembly  10  is usually impractical. As a result, the operator console  12  is often exposed to the elements, corrosive or abrasive particles, extreme temperatures, vibration, etc. Also, some locations in which an ESD valve is installed may be difficult or dangerous for a human operator to reach. 
         [0020]    In another known configuration depicted in  FIG. 1B , an ESD assembly  40  similarly includes in ESD controller  42  controlling an ESD valve  44  and one or more sensors. The ESD assembly  40  is coupled to an operator workstation  50  via a wired network connection  52 . The workstation  50  is disposed at a remote site, and accordingly allows operators to access the ESD valve  44  remotely. However, the configuration depicted in  FIG. 1B  still requires wiring and, sometimes, rewiring when a portion or the entirety of the ESD assembly  40  is upgraded. 
         [0021]    It is also possible to use a portable wired device such a Field Communicator manufactured by Emerson Electric Co., for example, to directly access an ESD assembly via a wired communication port, for example. Although generally more convenient for an operator that a stationary console (such as the operator console  12 ) and, in some cases, a workstation (such as the workstation  50 ) that provides remote network access to the ESD assembly, a portable wired device still requires that certain electronic components of the ESD assembly be exposed. In some environments (e.g., those that involve hazardous applications), exposure of electronic components is associated with an impermissibly high risk. 
         [0022]    Now referring to  FIG. 2 , in ESD assembly  100  is disposed in a pipeline  102  and may include components generally similar to those discussed above with reference to  FIGS. 1A and 1B . In particular, the ESD assembly  100  in the illustrated embodiment includes an ESD valve  104  coupled to an ESD controller  106 , a flow sensor  108  disposed upstream of the ESD valve  104 , and a pressure sensor  109  disposed downstream of the ESD valve  104 . In general, the ESD assembly  100  may include any suitable sensor configuration as well as other intelligent or non-intelligent components. Further, depending on the implementation, the components  104 - 109  are provided in a single assembly, as is the case in the example embodiment of  FIG. 2 , or as separate components interconnected in a wired manner or wirelessly (using radio frequency (RF) links, infrared (IR) links, etc.). 
         [0023]    In an embodiment, the ESD controller  106  is configured to support an industrial automation protocol such as HART, Profibus, Foundation Fieldbus, etc. To receive and transmit commands according to the supported industrial automation protocol, the ESD controller  106  is communicatively coupled to an wireless adapter  110  that includes an antenna and, in at least some cases, a processor. In some embodiments, the wireless adapter  110  is integral with the ESD assembly  100 , while in other embodiments, the wireless adapter  110  is provided separately for mounting on a suitable ESD assembly, for example. The wireless adapter  110  may be configured to transmit and receive commands according to a certain wireless communication protocol. In an embodiment, the wireless adapter  110  operates using a general-purpose short-range wireless protocol such as Bluetooth or a similar Institute of Electrical and Electronics Engineers (IEEE) 802.15 standard (e.g., version 802.15.1 ratified in 2005), for example. In operation, commands of the industrial automation protocol are layered over a portion of the Bluetooth communication stack. To this end, the ESD controller  106  may include drivers (or other software, firmware, or hardware components) configured to transmit commands of the industrial automation protocol and/or processing commands of the industrial automation protocol using Bluetooth or another general-purpose wireless communication protocol. More specifically, the ESD controller  106  may include components that provide the timing, synchronization, and other features necessary to operate according to the industrial automation protocol. 
         [0024]    The ESD controller  106  may be associated with an SIS system of a process plant. In an embodiment, the ESD controller  106  is a Fisher FIELDVUE™ digital valve controller, and the wireless adapter  110  is a 775 THUM™ adapter, each manufactured by Emerson Electric Co. 
         [0025]    An operator may utilize a wireless portable communication device  120  (for simplicity, “the wireless device  120 ”) to interact with the ESD assembly  100  and, more particularly, to initiate and/or monitor the progress of a partial stroke test. In an embodiment, the device  120  is a smartphone. In another embodiment, the wireless device  120  is a PDA. In yet another embodiment, the wireless device  120  is a wireless field communicator specifically adapted for use in a process control environment. Depending on the embodiment, the wireless device  120  may support a general-purpose wireless communication protocol to establish a wireless condition link with the wireless adapter  110  and/or a wireless industrial automation protocol such as WirelessHART, for example. In the latter case, the wireless device  120  and the adapter  110  may form a WirelessHART communication network and define respective nodes of the network. 
         [0026]    The wireless device  120  may further include an input device such as a keyboard, a mouse, etc. and an output device such as a display, as discussed in more detail with reference to  FIG. 4 . In an embodiment, a software module  122  resides in the memory of the communication device  120  and is configured to at least initiate a partial stroke test via a wireless link between the wireless device  120  and the ESD assembly  100 . In an embodiment, the software application  122  supports one or several valve control and diagnostics functions. The software application  122  may include a component adapted to layer commands of an industrial automation protocol (e.g., HART) over a general-purpose wireless communication protocol (e.g., Bluetooth). In another embodiment, the wireless device  120  includes a separate software component such as a driver to support messaging consistent with the industrial automation protocol using the general-purpose wireless communication protocol. 
         [0027]    Referring to  FIG. 3 , in ESD system  200  is generally similar to the ESD system  100  illustrated in  FIG. 2 . However, in ESD controller  202  is coupled to a wireless protocol adapter  210  that operates according to a wireless industrial automation protocol such as WirelessHART, wireless Fieldbus, etc. Similar to the wireless adapter  110  discussed above, the wireless protocol adapter  210  may be provided as a component of the ESD system  200  or separately for mounting on the ESD system  200  or otherwise coupling to the ESD controller  202 . In the system depicted in  FIG. 3 , a user operates a workstation  220  that is coupled to a wireless gateway to  222  via which the workstation  220  communicates with a wireless network  224 . The wireless network  224  may be a mesh wireless industrial communication network that includes several network devices, at least some of which provide a multi-hop communication path between the wireless gateway  222  and the adapter  210 . In another embodiment, the wireless gateway  222  and the adapter  210  are connected by a direct wireless link, accordingly defining a one-hop communication path. 
         [0028]    In the embodiment of  FIG. 3 , an operator may use the workstation  220  to access the ESD controller  202  and the ESD valve  204  via one or several direct (i.e., extending between a pair of devices) wireless communication links. Unlike a wired communication network, a wireless communication network generally is easier to form or adjust when devices are added to or deleted from the network, for example. In another configuration, the operator may utilize a portable communicator  240  that operates as anode in the wireless network  224  and connects to the adapter  210  via one or more intermediate links. The portable communicator  240  may be similar to the wireless device  120  or, in other embodiments, may be a wireless device specifically to operate in the wireless network  224 . In another embodiment, the portable communicator  240  is a laptop computer equipped with an adapter for communicating on the wireless network  224  and the necessary driver to support the communication protocol used by the wireless network  224 . 
         [0029]    Next,  FIG. 4  illustrates an example wireless portable communication device  300  that can be used in a communication system such as the one illustrated in  FIG. 2  or  FIG. 3 , for example. In an embodiment, the device  300  is used as the wireless device  120 . The device  300  includes a user interface  302  that in turn may include an input device such as a keyboard, a mouse, a trackball, a touchscreen, etc. and an output device such as a screen, an audio unit, etc. Further, the device  300  may include a processor  304  to execute instructions stored in a memory  306  that may include one or several of a persistent data storage component (e.g., a hard drive), a random-access memory (RAM) unit, a read-only memory (ROM) unit, etc. In general, the memory  306  may be any suitable type of a machine-accessible medium on which instructions are stored. Alternatively, in another embodiment, the processor  304  includes an application-specific integrated circuit (ASIC). 
         [0030]    The device  300  also may include an RF component module  310  such as a Bluetooth transceiver or a WirelessHART transceiver, for example, and a power storage unit  308  such as a battery. The RF component module  310  may be coupled to an antenna  312 . In general, the device  300  may be implemented using any suitable combination of software, hardware, and firmware components. Referring back to  FIG. 2 , the software module  122  may at least partially reside in the memory  306  to be executed by the processor  304 . 
         [0031]    Referring to  FIG. 5 , an example method  400  for establishing a wireless link between a portable device and an ESD valve, so that a partial stroke test can be initiated and/or conducted using the wireless link, may be implemented in a wireless portable communication device such as the device  120  or  300 , for example. At block  402 , a short-range wireless communication link, such as an RF link or an IR link, is established. The established wireless communication link may be a direct link between a device in which the method  400  is implemented and an ESD controller such as the ESD controller  106 . At block  404 , a set of one or several commands associated with a partial stroke test are retrieved. For example, the commands may be stored in the memory  306 . 
         [0032]    In an embodiment, the set of commands to be transmitted to the ESD valve includes such commands as a command to advance the valve stem to a certain position, a command to report the current sensed position of the valve stem, a command to report the flow rate sensed by a sensor associated with an ESD assembly, etc. In another embodiment, the set of commands includes a command to trigger a partial stroke test procedure stored and implemented by an ESD controller within the ESD assembly. In other words, the logic of a partial stroke test may be implemented by an ESD controller, the portable or stationary device used by the operator, each of the ESD controller and the device used by the operator, or distributed between the ESD controller and the device used by the operator. 
         [0033]    With continued reference to  FIG. 5 , the retrieved set of one or several commands is transmitted to the ESD controller over the wireless communication link at block  406 . As discussed above, the commands may be transmitted using a general-purpose wireless communication protocol, a wireless industrial automation protocol, or another suitable wireless protocol, and may accordingly include industrial automation commands (e.g., update the specified variable, report the specified variable, obtain device description information) or standard communication commands (read, write, etc.). 
         [0034]      FIG. 6  is a flow diagram of an example method  420  for wirelessly initiating a partial stroke test of an ESD valve and collecting diagnostic/status data from the ESD valve. Similar to the method  400  discussed above, the method  420  may be implemented in a wireless portable communication device such as the device  120  or  300 . At block  422 , a wireless connection is established using a direct wireless communication link or a multi-hop path that includes several direct wireless communication links. Next, at block  424 , a partial stroke test of the ESD valve is initiated. Data from the ESD valve indicative of the progress or the result of the partial stroke test is received at block  426 . For example, the data may include positioning data reported by a position sensor and the corresponding timestamps. Using the received data, a device that executes the method  420  may develop trending data, for example, or generate a report that an operator may use to more fully analyze the operation of the ESD valve. Also, in some embodiments, the received data may be used to document that a partial stroke test has been conducted. 
         [0035]    From the foregoing, it will be noted that the techniques discussed above allow operators to install devices such as valves as needed and incrementally expand process control networks, without having to provide wired network connections or direct wired connections to operator consoles, for example, or install multiplexers and other wired equipment. Further, these techniques significantly simplify installation as wireless components generally provide more flexibility than wired components. 
         [0036]    In accordance with some of the embodiments discussed above, a user can initiate a partial stroke test locally, i.e., from a distance that allows her to observe the progress of the test, but nevertheless provides sufficient safety as it does not require a physical contact with the ESD assembly. Further, as discussed above, it is not necessary to expose any electronic components of ESD valves that are wirelessly accessible by operators. Thus, both operational safety and device maintenance may be improved. 
         [0037]    While the present invention has been described with reference to specific examples, which are intended to be illustrative only and not to be limiting of the invention, it will be apparent to those of ordinary skill in the art that changes, additions or deletions may be made to the disclosed embodiments without departing from the spirit and scope of the invention.