Local user interface for explosion proof field instruments using capacitive touch sensing

Abstract

An apparatus includes a housing, a touch sensor, a display, and a control module. The housing has a body defining a volume to accommodate a process control device and is adapted to withstand a threshold internal pressure greater than an external pressure. The housing also has a transparent portion having a first surface and a second surface. The touch sensor is disposed proximate the second surface of the transparent portion and senses input received within a minimum distance from the first surface of the transparent portion. The display is disposed proximate the touch sensor and displays at least one adjustable variable corresponding to the process control device.

Description

Technical Field

[0001] The present invention relates generally to explosion proof process control equipment and, more particularly, to interfaces for explosion proof field instruments. Background Art

[0002] Process control equipment is generally used to control, measure, and / or perform other functions within the process, such as opening or closing valves and measuring process parameters. For example, some process control equipment can control the pressure of a control fluid used to position a pneumatic control device (such as a regulator). For example, an electro-pneumatic controller can be used to control field devices associated with the controller, which can be, for example, valves, valve positioners, switches, transmitters, and sensors (e.g., temperature, pressure, and flow rate sensors). In some forms, these controllers can control the pressure of a fluid in a pneumatic actuator or regulator entering a process control valve to position the process control valve or regulator. For example, a valve can be opened or closed in response to a control output received from a controller, or a measurement of a process parameter can be sent to a controller so that the controller can use the measurement as a control input. In some cases, a controller can be used in a hazardous environment that is susceptible to damage. In addition, controllers and regulators can use fluids that are flammable or explosive in nature. In this case, an explosion-proof container is used to contain explosions therein and protect the installed environment and other control instruments to ensure proper operation.

[0003] Explosion-proof process control equipment is capable of withstanding explosions and other impacts. When using explosion-proof process control equipment, the installation site and / or technicians must typically obtain clearance or thermal permits to perform work (e.g., maintenance, diagnostics, and / or routine inspections) on the equipment, or must instead deactivate and relocate the instrument in order to modify its operation. This process is both time-consuming and expensive. In addition, explosion-proof process control equipment typically does not allow access to the components contained therein, as any damage to the container may affect the controller's ability to withstand explosive forces. Therefore, in order to communicate with the controller (e.g., send commands, modify inputs, and / or adjust variables); existing explosion-proof controllers have used various technologies such as optical and / or magnetic systems to communicate with the components contained within the housing.

[0004] In an environment where an optical system is used to communicate with a controller, a transmitter / receiver pair is used to interface with a process control device in an explosion-proof container. Light from the transmitter is reflected from an input device (e.g., a user's finger), and the reflected light is received at a receiver, and the reflected light signals an input to the process control device. These systems are limited by power limitations and the fact that only a discrete number of inputs may be available. As an example, some explosion-proof controllers are used to power devices in an environment with a 4-20mA signal. Optical systems typically require at least half of this available power for normal operation of the system. Therefore, they are generally not used for more complex installations. In addition, these systems are limited because, in some cases, each required input of the instrument may require its own optical sensor, which may limit the total number of sensors that can be used within the housing due to size and power limitations. In addition, these systems may be unreliable due to the possibility of opaque materials such as dust and / or dirt deposited on the surface of the housing. Similarly, in an environment where a magnetic system is used, a physical button is actuated, which generates or destroys a magnetic field that signals an input. These interfaces are often constrained by their size and therefore may have only a limited number of discrete inputs. Summary of the invention

[0005] According to one aspect, an apparatus includes a housing, a touch sensor, a display, and a control module. The housing has a body defining a volume to accommodate a volume of a process control device and is adapted to withstand a threshold internal pressure greater than an external pressure. The housing also has a transparent portion having a first surface and a second surface. The touch sensor is disposed proximate the second surface of the transparent portion and senses input received within a minimum distance from the first surface of the transparent portion. The display is disposed proximate the touch sensor and displays at least one adjustable variable corresponding to the process control device.

[0006] In some forms, the housing may include a facing surface that contacts a portion of the first surface of the transparent portion. The facing surface may include a channel to accommodate a filler member to create a seal between the interface and the housing. The interface may be coupled to the housing via a sealing resin.

[0007] According to another aspect, a method of manufacturing a process control device includes providing a housing having a body defining a volume to accommodate the process control device and adapted to withstand a threshold internal pressure greater than an external pressure, and a transparent portion having a first surface and a second surface. The process control device is at least partially disposed in the volume of the housing. A touch sensor is disposed proximate the second surface of the transparent portion, a display is disposed proximate the touch sensor, and a controller is coupled to the touch sensor and the display. The housing is then sealed.

[0008] According to yet another aspect, a process control device includes a housing having a body defining a volume to accommodate a process control device having at least one variable; a second housing having a body defining a volume to accommodate at least a portion of the first housing; an interface coupled to at least one of the first housing or the second housing; a touch sensor disposed proximate a second surface of the interface; a display disposed proximate the touch sensor and displaying at least one adjustable variable of the controller; and a control module disposed within the housing. The controller is at least partially disposed within the volume of the first housing. The touch sensor is adapted to sense input received within a distance from the first surface of the interface. The control module is coupled to the sensor, the display, and the electro-pneumatic controller. Upon receiving the input, the sensor sends a signal to the control module to cause the control module to adjust the at least one adjustable variable.

[0009] So configured, by using a touch sensor, a user can communicate with a controller without having to deactivate the device. In addition, the touch sensor is able to operate in a variety of environments that are not suitable for optical sensors. The touch sensor can provide more design versatility by accepting any number of discrete or non-discrete inputs and / or adjustable variables while consuming less power. These parts also do not have a limited lifespan. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above needs are at least partially met by providing an explosion proof local user interface as described in the following detailed description, particularly when studied in conjunction with the accompanying drawings, wherein:

[0011] Figure 1 An exemplary process control system having an explosion proof controller according to various embodiments is shown;

[0012] Figure 2 It shows the various embodiments Figure 1 A cross-sectional view of an exemplary explosion-proof controller of a controller;

[0013] Figure 3 It shows the various embodiments Figure 1 and Figure 2 A perspective view of an exemplary explosion proof controller; and

[0014] Figure 4 A schematic diagram of an alternative field device having a first housing and a second housing according to various embodiments is shown.

[0015] It will be appreciated by the skilled person that the elements in the drawings are shown for simplicity and clarity, and are not necessarily drawn to scale. For example, the size and / or relative positioning of some of the elements in the drawings may be amplified relative to other elements to help improve the understanding of the various embodiments of the present invention. Moreover, common but easily understood elements that are useful or necessary in commercially feasible embodiments are not usually depicted, so as to less hinder the observation of these various embodiments. It should also be understood that certain actions and / or steps can be described or depicted in a specific order of occurrence, and those skilled in the art will understand that this specificity about the sequence is not actually required. It should also be understood that unless different clear meanings are set forth herein, the terms and expressions used herein have the common technical meanings given to these terms and expressions by those skilled in the art as described above. DETAILED DESCRIPTION

[0016] like Figure 1 As shown, the system 100 includes a process control device 110, depicted in this example as an electro-pneumatic controller, which is operatively coupled to a regulator 111. Specifically, for example, an outlet port 112 of the process control device 110 is operatively coupled to a top portion 114 of a housing 116 of the regulator 111 via an adapter 117. The regulator 111 includes an inlet 118 for receiving an inlet pressure in a pipeline 119, and an outlet 120 for directing an outlet pressure downstream of the regulator 111 in the process pipeline 119. The process control device 110 may be coupled to any number of alternative and / or additional process control devices disposed in an environment where the process control device 110 is desired to be used.

[0017] The process control device 110 includes a housing 122 having a body 123 including a supply port 124 for receiving a supply pressure from an external source, such as a supply source 136. The body 123 may also include any number of conduit connections, such as a first conduit connection 126 (e.g., a USB connection) for wiring to a computer 142 and a second conduit (not shown) connection for internal wiring.

[0018] The computer 142 can be communicatively coupled to the process control device 110 via a first conduit connection 140 for USB wiring. The transducer 144 can be disposed downstream of the outlet 120 of the regulator 111 and can be communicatively coupled to the process control device 110 for signal conversion. In one example of a typical operation of the process control device 110, the process control device 110 can sense system pressure via an input (e.g., a feedback signal) from the transducer 144. For example, the process control device 110 can read the input and compare it to a set point pressure, which the process control device 110 can receive from an external source (such as the computer 142) or from a profile on its onboard memory.

[0019] By one measure, if the housing 122 is able to withstand a threshold internal pressure (which can be used as a proxy for being able to contain an explosion therein), the housing 122 is considered explosion proof. In some examples, such a housing 122 can be designed to comply with one or more standards, such as the International Electrotechnical Commission (IEC) 60079. To determine whether the housing is able to contain an explosion therein, a test can be conducted with a detonation initiated within the housing 122 while measuring the pressure generated. The housing 122 must be able to withstand a safety factor exceeding the pressure generated. For example, a supply pressure of up to 120 psig / 8.2 bar (where 110 psig / 7.5 bar is typical) can be provided to the explosion proof housing 122. The threshold internal pressure can be about three times to about 15 times the supply pressure. Thus, the housing 122 can have any number of suitable sizes and / or configurations to withstand the threshold pressure, such as having a specific thickness (e.g., about 10 mm), material (e.g., aluminum and / or steel), etc. Of course, this is only one measure and standard for defining an enclosure as explosion proof or explosion resistant, and one of ordinary skill in the art will understand and appreciate alternative measures and standards.

[0020] exist Figure 2 and Figure 3 In the embodiment shown in , the process control device 110 also includes a controller 130, a transparent portion (e.g., a window) 150, a touch sensor 154, a display 158, and a control module 162. The controller 130 is used to control and / or adjust the operation of the regulator 111 and may include any number of adjustable variables that affect the operation of the regulator 111. The body 123 of the housing 122 defines a volume 128 to accommodate the controller 130. The housing 122 can be constructed of any number of materials that can withstand explosion pressures and / or forces in a variety of environments, such as those in accordance with the IEC 60079 standard. The body 123 can also define an opening 132 and a facing surface 134, which, in the example shown, is formed by a flange portion 135 surrounding the opening 132.

[0021] The transparent portion 150 includes a first surface 150a and a second surface 150b. The transparent portion 150 can be made of any number of suitable materials, such as a polymer or a non-crystalline amorphous solid (e.g., glass) that can withstand the threshold pressure and / or explosive forces in any number of environments as explained above. In some examples, the transparent portion 150 is generally transparent or translucent to allow a user to see the volume 128 of the housing 122. The transparent portion 150 is coupled to the housing 122 to at least partially cover the opening 132 via any number of fixing and / or sealing methods. In the example shown, the first surface 150a of the transparent portion 150 abuts and / or contacts the facing surface 134 of the body 123. In addition, in some examples, a sealing resin 152 can be used to fix the transparent portion 150 to the explosion-proof housing 122. Other examples of sealing components and / or methods can be used. In some examples, the flange 135 of the body 123 may form a channel 135 a that receives a filler member 164 (eg, an O-ring) to create an additional seal between the transparent portion 150 and the explosion-proof housing 122 .

[0022] In the example shown, the contact dimensions are used to ensure that the process control device 110 can withstand the creepage distance of the gas contained therein through the housing. Figure 2 The second dimension (indicated by "A" in FIG. 1 ) represents the contact length along the width of the transparent portion 150 and the body 123. More specifically, the dimension A represents the length of the sealing resin 152 along the width of the transparent portion 150. Figure 2 164 ) represents the contact length between the first surface 150a of the transparent portion 150 and the facing surface 134 "downstream" of the fill member 164 or sealed from the fill member 164. In these examples, the treacherous path is equal to the contact size, which is the sum of the lengths A and B. If the contact size is greater than about 10 mm, the process control device 110 can avoid the gas creepage distance through the housing 122.

[0023] In the example shown, the touch sensor 154 has a first surface 154a and a second surface 144b. The first surface 154a of the touch sensor 154 is disposed near the second surface 150b of the transparent portion 150. "Near" means in direct contact or very close. In the example shown, the first surface 154a of the touch sensor 154 abuts against the second surface 150b of the transparent portion 150, but in other examples, there may be a gap between the first surface 154a of the touch sensor 154 and the second surface 150b of the transparent portion 150. As will be appreciated by those of ordinary skill in the art, the size of the gap (or lack of a gap) may depend on the sensitivity of the sensor 154. In some examples, an adhesive (e.g., LORD 7545A / B polyurethane adhesive, for example) may be used to couple the touch sensor 154 to the transparent portion 150, and in other examples, any number of devices (such as mechanical fasteners) may be used to couple the sensor 154 to the transparent portion 150.

[0024] The touch sensor 154 may be any type of sensor that measures or senses input received within a certain distance from the first surface 150a of the transparent portion 150. Thus, the term "touch" may refer to physical contact between two objects and / or close contact between two objects. For example, the touch sensor 154 may be a capacitive touch sensor that measures local changes in capacitance on the first surface 150a of the transparent portion 150. In other examples, the touch sensor 154 may be a deflection-based capacitor that measures local deflection. In examples using capacitive sensors, the capacitive sensor may be in the form of a self-capacitive sensor (where an object (such as a finger) loads the sensor or increases parasitic capacitance to ground) or a mutual capacitance sensor (where an object changes the mutual coupling between sequentially scanned row and column electrodes). Other examples of suitable touch sensors 154 may be used.

[0025] For example, in examples where the display 158 is disposed externally to the housing 122, a resistive touch sensor may be used and coupled to the display 158. In such a configuration, the display 158 and touch sensor 154 may be remotely located when the process control device 110 is mounted in a difficult to access location. Additionally, in these configurations, the housing 122 may be provided without transparent portions, and thus the body 123 may be unitary. In this way, the process control device 110 may be completely enclosed, which may avoid fluid (e.g., liquid or gas) creepage distance issues where the fluid may eventually seep out of the housing 122.

[0026] Touch sensor 154 can be in the form of a thin film sensor and is communicatively coupled to control module 162. The sensitivity of sensor 154 can determine, at least in part, the maximum distance at which an input can be sensed. For example, sensor 154 can be a projected capacitive touch sensor that projects an electromagnetic field greater than the thickness of transparent portion 150 so as to diffuse on its surface. In another example, sensor 154 can use frustrated total internal reflection (FTIR) to sense touch in a case where the transparent portion can be an acrylic or other suitable material to maintain total internal reflection. In any case, as understood by those of ordinary skill in the art, touch sensor 154 can sense input received relative to transparent portion 150 or input close to the transparent portion.

[0027] Display 158 is also communicatively coupled to control module 162 and generates one or more images depicting corresponding to one or more adjustable variables of controller 130. Display 158 may be any type of suitable display, such as a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display panel (PDP), an organic light emitting diode (OLED) display, etc. In some examples, display 158 may be a lower-function character display (e.g., a thin film transistor or TFT display) with a lower resolution and may be limited to providing a discrete number of inputs.

[0028] The control module 162 may be any type of device having inputs and outputs to control and / or regulate the operation of the controller 130. For example, the control module 162 may be any form of a computing device having any number of inputs and outputs, non-transitory memory, and a processor programmed to control and / or regulate the operation of the controller 130. The control module 162 may include any number of additional components to control and / or regulate the operation of the controller 130.

[0029] In operation, the user can view the image generated by the display 158 through the transparent portion 150, and may wish to adjust the adjustable variables of the controller 130. By touching (or approaching or contacting) the first surface 150a of the transparent portion 150, the touch sensor 154 senses the contact or near contact by detecting the change in the current derived from any object that can hold an electric charge (e.g., the user's finger) as a change in capacitance at a specific location. The sensed contact or near contact is sent to the control module 162, which then determines one or more specific adjustable variables of the controller 130 for adjustment. Then, the control module 162 sends a signal to the controller 130 to adjust the adjustable variables. Therefore, any number of discrete inputs can be adjusted via the display 158 and the sensor 154. In some examples, the interaction with the display 158 can also exist in a non-discrete manner using the sensor 154. Specifically, in some examples, the user can use any number of non-discrete inputs (such as sliding to pan, multi-finger gestures to move and / or zoom interfaces, etc.) to interact with the content on the display 158. Thus, display 158 may present a complex interface to a user to adjust any number of variables, and display 158 may accommodate multiple graphical user interfaces.

[0030] So configured, operating parameters of the controller 130 can be adjusted on the fly because the user does not need to deactivate and / or remove the process control device 110 from its operating environment. In addition, when adjusting the adjustable variable, the user does not need to physically contact the transparent portion 150, which can avoid reducing the visibility of the display 158 due to dust and / or dirt deposited on the transparent portion 150. Nevertheless, even in the presence of dust and / or dirt on the first surface 150a of the transparent portion 150, the touch sensor 154 can still sense the change in capacitance of the transparent portion 150. In the example where the touch sensor 154 is a projected capacitive sensor, the touch sensor 154 can be highly sensitive to accurately sense the change in capacitance through the transparent portion 150, which is appropriately wide or thick to withstand the threshold internal pressure and / or one or more explosions.

[0031] In an example where the sensor 154 takes the form of a deflection-based capacitor that measures local deflection, a body 123 without a transparent portion 150 can be provided, and the body 123 can rely on an indication of a discrete input on the body 123. For example, when the housing is constructed of a metallic material (e.g., aluminum) and a deflection-based sensor is used, the surface of the body 123 can have an etching, paint, or other indication of a discrete input. In this way, a user can provide input by pressing a local area corresponding to a discrete input. Thus, the housing 122 can be a unitary structure that can reduce and / or eliminate any fluid creepage distance issues.

[0032] Additionally, in some embodiments, an external display (not shown) can be used with external sensors having any number of discrete and / or non-discrete inputs to provide an indication of the input to the controller 130. In these examples, the body 123 can be coupled to the external display using any number of suitable methods. So configured, the controller 130 can have a reduced footprint that is still able to contain the explosion, but the external display can be remotely located for easy access.

[0033] like Figure 4 As shown, in some examples, the process control device 230 can be disposed in the internal volume of the first housing 210, which is in turn disposed in the internal volume of the second housing 231. In some examples, the second housing 231 can withstand a threshold internal pressure greater than the external pressure, while the first housing 230 can withstand or cannot withstand a threshold internal pressure greater than the external pressure. The second housing 231 can also accommodate any number of additional components, such as an interface 255 in the form of a display 258 and / or input buttons, etc. In addition, the second housing 231 can include a sensor 254 that can be a capacitive or other sensor previously described. The electro-pneumatic controller 230 can be communicatively coupled to the interface 255 via a communication link 260 (which can be one or more wired or wireless components of any type). In other examples, these components can be located outside the second housing 231. In the event of an explosion, the first second housing 231 will contain the explosion while shielding the additional components disposed externally from damage.

[0034] So configured, the process control device 110 described herein can allow additional interaction with the components contained therein, thereby allowing increased system complexity. In some embodiments, the controller 130 can be used in a diagnostic mode, whereby the display 158 provides an interface that illustrates the current operating conditions of the control system 100. In other words, the display 158 can be used not only to interact with the controller 130, but it can also be used to interact with other components (e.g., regulator 111) located upstream or downstream of the controller 130 within the system 100. In some of these examples, the display 158 and / or the sensor 154 can be used in non-explosive environments where a touch (or near-touch) screen is required. In addition, due to lower power limitations, the process control device 110 can use an advanced graphical user interface to accommodate additional inputs and better control.

[0035] Those skilled in the art will appreciate that various modifications, changes and combinations may be made to the embodiments described above without departing from the scope of the present invention, and such modifications, changes and combinations will be deemed to be within the scope of the inventive concept.

[0036] The patent claims at the beginning of this patent application are not intended to be interpreted under 35 U.S.C. §112(f) unless conventional means-plus-function language is expressly recited, such as "means for" or "steps for...", when expressly recited in the claim(s). The systems and methods described herein relate to improvements in computer functionality and improve upon the functionality of conventional computers.

Claims

1. A device for a process control device, comprising: a housing having a body defining a volume to house the process control device and adapted to withstand a threshold internal pressure greater than an external pressure, the body having a transparent portion having a first surface, a second surface, and a third surface extending between the first surface and the second surface; a touch sensor disposed proximate the second surface of the transparent portion, the touch sensor adapted to sense input received within a minimum distance from the first surface of the transparent portion; and a display disposed proximate to the touch sensor and the process control device and communicatively coupled to the touch sensor and the controller to display at least one adjustable variable of the controller; wherein at least a portion of the third surface of the transparent portion defines a first contact dimension, and at least a portion of the first surface of the transparent portion defines a second contact dimension, wherein the total length of the first contact dimension and the second contact dimension defines a variable path, wherein the variable path is greater than 10 mm.

2. The apparatus according to claim 1, further comprising: A control module is disposed within the housing and is coupled to the touch sensor, the display, and the controller; wherein upon receiving the input, the touch sensor sends a signal to the control module to cause the control module to adjust the at least one adjustable variable.

3. The device according to claim 1, wherein: The touch sensor includes a capacitive sensor.

4. The device according to claim 3, wherein: The capacitive sensor comprises a self-capacitive sensor.

5. The device according to claim 3, wherein: The capacitive sensor comprises a mutual capacitance sensor.

6. The device according to claim 1, wherein: The touch sensor includes a deflection based sensor.

7. The device of claim 1, wherein: The touch sensor includes a projection sensor.

8. The device according to claim 1, wherein: The transparent portion includes a window, and the window is composed of a polymer or a non-crystalline amorphous solid.

9. The device according to claim 1, wherein: The housing includes a facing surface for contacting the portion of the first surface of the transparent portion to define the second contact dimension.

10. The device according to claim 9, wherein: The facing surface includes a channel, and the device further includes a filling member adapted to be disposed within the channel to form a seal between the transparent portion and the housing.

11. The device according to claim 8, wherein: The window is coupled to the housing via a sealing resin.

12. The device according to claim 1, wherein: The display comprises a liquid crystal display.

13. A method of manufacturing a process control device, the method comprising: providing a housing having a body defining a volume to house a controller that controls operation of a field device and adapted to withstand a threshold internal pressure greater than an external pressure, the body further having a transparent portion having a first surface, a second surface, and a third surface extending between the first surface and the second surface; disposing the process control device at least partially within a volume of the housing; disposing a touch sensor adjacent to the second surface of the transparent portion; Disposing a display near the touch sensor; coupling a control module to the touch sensor and the display; and sealing the housing so that the controller is accommodated therein, and so that at least a portion of the third surface of the transparent portion defines a first contact dimension, and at least a portion of the first surface of the transparent portion defines a second contact dimension, wherein the total length of the first contact dimension and the second contact dimension defines a variable path, wherein the variable path is greater than 10 mm.

14. The method according to claim 13, wherein: The housing is sealed with a sealing resin.

15. The method according to claim 13, wherein: The housing includes a facing surface including a channel, and the method further includes disposing a filling member in the channel to form a seal between the transparent portion and the housing.

16. An apparatus for a process control device, comprising: a first housing having a body defining a volume for accommodating a process control device; a second housing having a body defining a volume for accommodating at least a portion of the first housing; an interface coupled to at least one of the first housing or the second housing, the interface defining a variable path greater than 10 mm; a touch sensor disposed proximate the interface, the touch sensor being adapted to sense input received within a minimum distance from the interface; a display, the display being disposed near the touch sensor; and a control module disposed within the first housing, the control module being coupled to the touch sensor, the display, and the process control device.

17. The device according to claim 16, wherein: The second housing is capable of withstanding a threshold internal pressure greater than an external pressure.

18. The device according to claim 16, wherein: The second housing also houses a field instrument.

19. The device according to claim 16, wherein: The sensor comprises a capacitive sensor.

20. The device according to claim 19, wherein The capacitive sensor comprises a self-capacitive sensor.

21. The device according to claim 19, wherein The capacitive sensor comprises a mutual capacitance sensor.

22. The device according to claim 16, wherein: The interface is composed of a polymer or a non-crystalline amorphous solid.

23. The device according to claim 16, wherein: The interface is comprised of a metallic compound, wherein the touch sensor comprises a deflection-based sensor.

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