One-way data transmission of field devices

Abstract

The field device includes a process communication module, a graphic display, and a controller. The process communication module is configured to communicate according to a process industry standard communication protocol. The controller is operably coupled to the process communication module and the graphic display, and is configured to cause the graphic display to generate a machine-readable display output in a responsive manner.

Description

Background Art

[0001] Field devices (such as process variable transmitters) are used in the process control industry to remotely sense process variables. Field devices (such as actuators) are used by the process control industry to remotely control physical parameters of a process, such as flow, temperature, etc. The process variables can be transmitted from the field device to a control room, such as a process variable transmitter for providing information about the process to a controller (e.g., in the control room). The controller can then transmit the control information to the field device (such as an actuator) to modify the parameters of the process. For example, information related to the pressure of a process fluid can be transmitted to a control room and used to control a process (such as an oil refinery).

[0002] Typically, field devices have field-hardened housings so that they can be installed outdoors in relatively harsh environments and withstand extreme weather conditions of temperature, humidity, vibration, mechanical shock, etc. These devices can also typically operate at relatively low power. For example, field devices that receive all of their operating power from a known 4mA to 20mA loop are currently available.

[0003] Field devices (e.g., process variable transmitters) are used to monitor process variables associated with fluids (such as slurries, liquids, steam, and gases) in chemical, pulp, oil, gas, pharmaceutical, food, and other fluid processing plants. Process variables include, but are not limited to, vibration, viscosity, velocity, volume, mass, energy, pressure, temperature, flow, level, pH, conductivity, turbidity, density, concentration, chemical composition, and other fluid properties. Field devices (such as process actuators) include control valves, pumps, heaters, agitators, coolers, solenoids, vents, and other fluid control devices.

[0004] Some field devices communicate according to the wire process communication protocol. For example, some field devices employ digital circuits that communicate with the controller using digital signals superimposed on the analog current signal flowing through the process control current loop. An example of such a technology is the Highway Addressable Remote Sensor Communication protocol. The ® protocol and other such protocols generally include a set of commands or instructions that can be sent to a field device to elicit a desired response, such as device control or interrogation.

[0005] Another process communication protocol is called FOUNDATION TMFieldbus protocol. This protocol is intended to define a communication layer or communication protocol for transmitting information on a process control loop. The Fieldbus protocol specification is ISA-S50.01-1992, published by the Instrument Society of America in 1992. Another known wired process communication protocol is called Profibus. Yet another known wired process communication protocol is called Modbus. Other wired process communication protocols are also known.

[0006] Recently, wireless technology is being used to communicate with field devices. Wireless operation simplifies field device wiring and setup. One specific form of wireless process communication is set forth in IEC62591 (WirelessHART). However, it is also desirable to provide additional wireless communication capabilities for field devices, such as communication according to known WiFi, Bluetooth, and / or infrared (IrDA) protocols.

[0007] The environment in which the field device operates may include volatile or even explosive gases. Therefore, high requirements need to be placed on such field devices to ensure that they do not inadvertently generate ignition sources in such an environment. One way to ensure safety is to place the circuits of the field device in an explosion-proof housing. An example of explosion-proof specifications is described in the "Approval Standard for Explosion-Proof Electrical Equipment General Requirements, Classification Number 3615, issued by the American Factory Insurance Alliance (Factory Mutual Research) in March 1989". Compliance with explosion-proof specifications (such as the explosion-proof specifications described above) helps to ensure that even if the circuits in the field device become overheated or sparks, the ignition that occurs in the housing of the field device will not leak into the larger volatile process environment. Another way to ensure the safety of the process environment is to make the electronic circuit itself meet the intrinsic safety requirements. An example of an intrinsically safe specification is set forth in "Approval Standard Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II and III, Division 1 Hazardous (Classified) Locations, Classification Number 3610, issued by the American Factory Insurance Alliance in October 1988." Providing field devices that operate in accordance with explosion-proof specifications and / or intrinsically safe specifications helps ensure the safety of the process environment and the safety of personnel interacting with such field devices.

[0008] Safety is a concern in a process environment where a technician needs to interact with components within a field device (such as attaching test leads to configure or diagnose a field device), and the act of opening an enclosure (i.e., removing a cover) may require specific authorization (such as a hot work permit) before such work can be performed. In some cases, it may be necessary to shut down process control operations in a process control environment before performing work on a field device to prevent potential electrical sparks from causing an explosion in a hazardous gas atmosphere. Summary of the invention

[0009] The field device includes a process communication module, a graphic display, and a controller. The process communication module is configured to communicate according to a process industry standard communication protocol. The controller is operably coupled to the process communication module and the graphic display, and is configured to cause the graphic display to generate a machine-readable display output in a responsive manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic perspective view of a field device for which embodiments of the present invention are particularly useful.

[0011] Figure 2 is a block diagram of a field device in which embodiments of the present invention may be practiced.

[0012] Figure 3 is a schematic diagram of unidirectional data transmission from a field device according to an embodiment of the present invention.

[0013] Figure 4A and Figure 4B The diagram illustrates a user's mobile device processing a machine-readable image obtained from a field device according to an embodiment of the present invention.

[0014] Figure 5 is a flow chart of a method of transmitting data from a field device according to an embodiment of the present invention.

[0015] Figure 6 is a flow chart of a method of establishing bidirectional wireless communication with a wireless field device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] Embodiments of the present invention generally simplify and speed up the interaction between a user or technician and a field device operating on site. When a technician needs to open the housing of a field device, the process itself is relatively cumbersome and slow. In some cases, the technician may need to obtain a hot work permit. The technician must then open the housing of the field device, attach wires, download information via a digital protocol, and then re-cover the cover. Even without considering the time required to obtain a hot work permit, this entire process may take several minutes. Recently, it has become useful to interact with field devices with wireless communication capabilities, thereby avoiding the need to remove the cover and possibly obtain a hot work permit. For example, U.S. Patent Application Publication No. 2019 / 0103914 considers the use of low-power Bluetooth (BLE) communication with a field device (shown as a valve controller). Although wireless communication with a field device generally avoids the need to remove the cover, wireless communication itself may bring other challenges. For example, some users may be sensitive to safety issues using such wireless communication.

[0017] Another difficulty in using current field devices to interact is that field devices are typically relatively low-power devices and use relatively small digital displays. For example, some current field devices use liquid crystal displays with relatively low resolutions and are sized so that they can only display a dozen human-readable words and numbers on the screen at any one time. This makes it difficult to provide users or technicians with all the information they can find in a concise manner. Therefore, current devices are slightly limited in their ability to provide large amounts of digital data to users or technicians at the field device, while still ensuring the safety and confidentiality of the process.

[0018] The embodiments described herein generally utilize a machine-readable display output on a field device in conjunction with a technician's or user's camera (such as on a mobile device) to quickly and securely transfer large amounts of digital data from an operational field device to a technician's mobile device. Thus, instead of providing a dozen human-readable words or numbers, the device may display a machine-readable image (e.g., a QR code, barcode, or other suitable image) captured by the user's or technician's device.

[0019] The popularity of smart devices in process devices is increasing. These smart devices are typically equipped with high-resolution cameras that can capture machine-readable coded images. The processing of these coded images allows faster data transmission than when using wired connections. It is believed that time savings can be achieved due to the fact that transmission can occur without removing the cover of any field device. This data transmission is also unidirectional and point-to-point. This alleviates some security issues associated with current wireless options. In one embodiment, the display of the coded image on the field device is started by pressing a local button or other suitable technology.

[0020] Figure 1 1 is a schematic perspective view of a field device to which embodiments of the present invention are particularly applicable. Field device 100 is illustrated as a process fluid pressure transmitter having a process fluid inlet 102 configured to be coupled to a process 104. The process fluid pressure transmitter is disposed within a sensor body 105 and provides an electrical signal related to process fluid pressure. This electrical signal is operated by a controller (such as a microprocessor) and converted into a process fluid pressure, which can be displayed by a display 106 and / or communicated to a remote device (such as a control room). Display 106 is typically a graphical display, wherein the display 106 has a number of elements (dots or pixels) that can be joined to produce a display output (usually in the form of letters, numbers or icons). The process fluid pressure transmitter has a rugged housing 108 with at least one cover 110 that is removable to access the interior of the field device 100. In addition, the field device 100 may include one or more local user interface elements (such as buttons 112, 114) that allow a user to interact with the field device. Note that field device 100 is only one example of many different field devices in which embodiments described herein may be practiced.

[0021] Figure 2 is a block diagram of a field device in which embodiments of the invention may be practiced. Circuitry 120 is disposed within housing 108 and includes a loop communication module 122 , a power module 124 , a controller 126 , a local operator interface 128 , a sensor interface circuit 130 , and a sensor 132 .

[0022] The process communication circuit 122 is configured to communicate according to a process industry communication protocol, such as Protocol, Foundation Fieldbus (FOUNDATIONTM Fieldbus) or WirelessHART (IEC62591) protocol. Process communication allows the field device 100 to report process variables or receive process commands through a process communication loop. The process communication circuit 122 is coupled to the controller 126 to allow the controller 126 to interact with the process controller and / or other field devices through a process communication loop or process communication segment.

[0023] The controller 126 is any suitable device capable of executing programming steps to provide its field device functions. In one example, the controller 126 includes a microprocessor, and associated memory and timing circuits that execute programming steps to provide field device outputs, or receive field device commands and generate process actuator outputs. The controller 126 is coupled to a local operator interface circuit 128.

[0024] Examples of local operator interface circuitry 128 include display 106 and input devices 112, 114. Display 106 may include any suitable display technology, including but not limited to light emitting diode displays (such as, OLED displays or AMOLED displays), electroluminescent displays (ELD), liquid crystal displays (LCD), plasma displays, quantum dot (QLED) displays, vacuum fluorescent displays, electronic ink displays, or any suitable technology capable of rendering machine-readable images. Although input devices 112, 114 are shown as buttons, any suitable input element according to the embodiments described herein may be used. For example, such elements may include magnetic switches, Hall switches, reed switches, capacitive touch screens, resistive touch screens, rotary encoders, photosensitive sensors (such as, photodiodes), acoustic sensors, or any other suitable element capable of sensing user interactions and providing signals indicating such interactions to controller 126.

[0025] The sensor interface circuit 130 allows the controller 126 to interact with a sensor 132. In embodiments where the field device is a process variable transmitter, the sensor interface circuit 130 includes an analog-to-digital converter coupled to the sensor 132 in the form of a process variable sensor, such as a temperature or pressure sensor. In embodiments where the field device is a process actuator, such as a motor or valve positioner for producing valve movement, the sensor interface circuit 130 may include suitable current drive circuitry to interface with a sensor, such as a transducer.

[0026] Figure 3Schematic diagram of one-way data transmission from a field device according to an embodiment of the present invention. In the illustrated example, the field device 200 is a process variable transmitter having a display 206 and buttons 212, 214. In one embodiment, the display 206 is disposed within a housing / enclosure 208, which may be explosion-proof. The display 206 can be viewed through a window in the housing 208, so that the display 206 can be viewed without opening the housing 208.

[0027] like Figure 3 As can be seen, a user or technician's smartphone 230 is brought into proximity with the field device 200 so that a camera 232 of the smartphone 230 can capture an image of a machine-readable display output 234 presented on the display 206. In the illustrated example, the machine-readable display output 234 is a two-dimensional barcode, such as a QR code. However, any suitable machine-readable image may also be used. In one embodiment, the process variable transmitter 200 is caused to generate the machine-readable image 234 by a technician interacting with one or both of the buttons 212, 214. However, in another example, the process variable transmitter may be caused to generate the machine-readable display output 234 upon receipt of a suitable command via process communications.

[0028] In another embodiment, where the field device 200 includes a photodiode, the field device can detect a flash of light emitted from the user's smartphone, thereby substantially detecting the flash signal as a trigger condition for displaying the machine-readable image 234. Many smart devices with cameras are also equipped with a light source capable of providing a flash for photographing. This flash can be used to cause the field device to display the machine-readable image 234. In addition, the flash signal can also be used to signal the field device that the user's smart device has finished reading the machine-readable image 234, and the field device 200 can display the next machine-readable image in a series of machine-readable images. In this way, many images can be processed by the user's smart device without the user taking actions to advance the image display or otherwise control the image display.

[0029] In yet another example, the process variable transmitter 200 may be caused to generate a machine-readable image 234 upon the occurrence of an event, such as a violation of an upper or out-of-range measurement limit, or a failure of a component within the process variable transmitter 200. For example, in embodiments utilizing an electronic ink display (electronic ink displays generally do not require power to maintain their display state) upon a failure of the process variable transmitter 200, a diagnostic or debug image may be generated on the display 206, and the display may remain on the display 206 even if power is lost within the process variable transmitter.

[0030] When a user or technician's device captures one or more images of the machine-readable display output 234, the smart device may automatically, or under the control of the user, process the one or more machine-readable images to extract data from the machine-readable images. Figure 4A As shown, an application executing on the technician's device 230 can provide an indication of such processing. When the processing is completed, the extracted data can then be displayed to the technician, such as in Figure 4B Note that a single machine-readable image may be processed to provide information about a user's device, or multiple machine-readable images may be obtained sequentially from a field device and can be processed to provide said information about a user's device.

[0031] It is believed that embodiments of the present invention will generally improve interaction with field devices in many different scenarios.

[0032] In the first scenario, a machine-readable display can be used to provide detailed information about an individual field device. For example, such information may include, but is not limited to, an order code or options for the field device, thereby allowing a user to easily reorder the exact same field device or spare parts. Such information may also include the status of all configuration parameters in the field device. Using machine-readable codes like this can replace existing RFID tag technology.

[0033] In another scenario, the machine-readable information can be used to provide an indication of the type of device. This may help point to a URL or link to product documentation for a specific model of field device, saving the user or technician time in looking up the information themselves.

[0034] In yet another example, a machine-readable image can provide a process data history, diagnostic log, or other large portion of data relatively quickly. A local display is not an ideal way to display very long strings or graphics, which may be shown, for example, in a large display. Instead, a coded image can be displayed that contains a history of process values ​​and / or diagnostic / calibration logs of a field device in a particular format that can be captured and processed by a user or technician's smart device. Finally, such data can be provided in a user-friendly manner, such as Figure 4B The graph or table shown in .

[0035] The above examples only illustrate the improved information transmission between the field device and the user or technician's smart device by the relatively limited display substrate area on the field device. The coded image described herein can take many forms. General examples include two-dimensional barcodes or standard barcodes. These images can be shown as unique items on the screen, or can be shown together with some human-readable text.

[0036] In addition, the embodiments described herein can be used to facilitate improved security for two-way wireless communications between a user's device and a field device. For example, a field device that is part of a wireless communication handshake protocol or authentication may require data extracted from a machine-readable image. In one example, the data encoded in the image may be a password or key that the user needs to capture with their smart device to authenticate their smart device connected via another wireless protocol (such as WiFi or Bluetooth). Therefore, if there is a situation where the user is concerned about security and sufficient security is provided near the field device to confirm authentication, using an encoded image as a form of two-factor authentication will alleviate security issues.

[0037] Figure 5 3 is a flow chart of a method for transmitting data from a field device according to an embodiment of the present invention. The method 300 begins at block 302, where a user or technician places a smart device with a camera near a display of a field device. Examples of such smart devices include a handheld field maintenance tool 304. However, the technician's device may be a personal digital assistant (such as indicated at block 306), a smart phone 308, or any other suitable smart device with a camera capable of acquiring an image of a display (such as indicated at block 310). Once the camera is in proximity to the display of the field device, the field device is caused to generate a machine-readable image on its display, and the user's smart device acquires an image of the display of the field device, as shown in block 312.

[0038] Once the image has been acquired, the image is processed at block 314 according to suitable known image processing techniques to extract the encoded data from the machine-readable image. The extracted information itself may then be used to supplement the extracted information at optional block 316. For example, such supplementation may include a user or technician's device using the extracted URL to obtain information from the Internet 318. In another example, the extracted information about the field device may be used to reference a device description (DD) of the field device, as indicated at block 320.

[0039] Additionally, any other suitable information source may be used to supplement the information based on the extracted information, as indicated at block 322. Finally, at block 324, the extracted data and any suitable supplemental data are displayed to the user on the user's smart device. Figure 4B An example of such a display is shown.

[0040] Figure 6 4 is a flow chart of a method for establishing two-way wireless communication with a wireless field device according to an embodiment of the present invention. Method 400 begins at box 402, where the field device provides a machine-readable image on its display and the user or technician's smart device acquires its image. The machine-readable image can be a machine-readable image according to any of the examples set forth above. Then, at box 404, the user or technician's smart device extracts data from the machine-readable image according to a suitable data extraction technique for the specific machine-readable image technology used. Then, at box 406, the extracted data is used to initiate two-way wireless communication with the field device. Any suitable two-way wireless communication protocol can be used. Examples include wireless fidelity (WiFi) 408, Bluetooth (such as low-power Bluetooth 410), wireless HART 412, or any other suitable wireless communication technology now known or later developed, as indicated by box 414.

[0041] An example of using the extracted information to establish two-way wireless communication includes extracting a password, such as a one-time password generated by the field device and encoded in a machine-readable image. Then, after successfully extracting the password from the machine-readable image, the user can enter the extracted password back into the field device through a wireless communication initiation process (e.g., Bluetooth pairing). This authentication factor can be used in addition to single-factor authentication (such as a username and password) to ensure that the user or technician is physically close to the field device. This can provide increased wireless information security, which can also facilitate the ability to use two-way wireless communication in many instances.

[0042] 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.

Claims

1. A field device comprising: a process communications module configured to communicate according to a process industry standard communications protocol; Graphic display; a controller operably coupled to the process communication module and the graphic display, the controller configured to responsively cause the graphic display to generate a machine-readable display output; wherein the controller is configured to cause the graphical display to generate a series of machine-readable display outputs; and Wherein the field device further comprises a light-sensitive sensor coupled to the controller, and wherein the controller is configured to cause the graphical display to step through the series of machine-readable display outputs based on a signal from the light-sensitive sensor.

2. The field device of claim 1 further comprising a housing housing the graphic display and the controller. The field device of claim 2 , wherein the housing is configured to comply with explosion-proof regulations. 4 . The field device of claim 1 , wherein the controller is configured to responsively cause the graphical display to generate the machine-readable display output upon receiving a button press. 5 . The field device of claim 1 , wherein the controller is configured to cause the graphical display to generate the machine-readable display output in response to receiving a command via process communications.

6. The field device of claim 1, wherein the controller is configured to responsively cause the graphical display to generate the machine-readable display output upon the occurrence of a device failure.

7. The field device of claim 6, wherein the machine-readable display output indicates a fault in the device.

8. The field device of claim 1, wherein the graphic display output comprises a plurality of pixels.

9. The field device of claim 1, wherein the graphic display is a liquid crystal display.

10. The field device of claim 1, wherein the graphical display is an electronic ink display.

11. The field device of claim 1, wherein the machine-readable display output is a bar code.

12. The field device of claim 11, wherein the barcode is a two-dimensional barcode.

13. The field device of claim 1, wherein circuitry of the field device is configured to comply with intrinsic safety regulations.

14. The field device of claim 1, wherein the field device is a process variable transmitter.

15. The field device of claim 1, wherein the field device is a process actuator.

16. A method of transmitting information from a field device according to any one of claims 1 to 15, the method comprising: causing the graphical display of the field device to generate a machine-readable display output; obtaining at least one image of the machine-readable display output; processing an image of the machine-readable display output to obtain extracted data; as well as The extracted data is displayed.

17. The method of claim 16, wherein the machine-readable display output is a two-dimensional barcode.

18. The method of claim 16, further comprising using the extracted data to obtain supplemental information.

19. The method of claim 18, wherein the supplemental information is obtained via a remote connection.

20. The method of claim 16, wherein the at least one image comprises a series of images.

21. The method of claim 20, wherein the series of images are displayed sequentially on a display of a field device.

22. The method of claim 16, wherein the graphic display is located within an explosion proof enclosure.

23. A method of establishing a wireless communication session with a field device according to any one of claims 1 to 15, the method comprising: causing the graphical display of the field device to generate a machine-readable display output; obtaining an image of the machine-readable display output; processing an image of the machine-readable display output to obtain extracted authentication information; providing the extracted authentication information to the field device; as well as Upon receiving the extracted authentication information, the field device provides a two-way wireless communication session.

24. The method of claim 23, wherein the extracted authentication information is a key generated by the field device and can only be used once.

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