A CONTROLLER CONFIGURED FOR THERMAL PROCESS CONTROL FIELD OF THE INVENTION
The present invention relates to a controller for thermal process control, the controller comprising a housing encapsulating computer means for processing data, data storage means for storing data, a data interface for communicating data with the thermal process control system, and a front surface comprising a user interface for communication with a user.
BACKGROUND OF THE INVENTION
In some controllers for thermal process control a user interface comprises a display capable of presenting information to the user and a user input interface to allow controller configuration by interaction with a user. The controller may be programmed with a navigation menu for browsing controller information and setting various parameters. The user is then able to read information from the controller display and navigate the controller menu in order to retrieve relevant information and set relevant controller parameters. Such controllers are subject to a highly competitive market relating to manufacturing costs. Accordingly, the displays are most often in the form of simple digital displays with very limited resolution. The typical display has a number of fixed symbols being illuminated or not according to the controller user output as well as a few seven segment displays. The typical user input interface is in the form of a few tactile switches. This relatively simple user interface is mainly chosen according to manufacturing cost minimization .
For thermal process control, such as for controlling refrigeration or an air-conditioning system, the controller is normally integrated in the equipment, e.g. in a lower or upper part of the front of display furniture in supermarkets or on the front of air-conditioning systems.
Modern refrigeration and air-conditioning systems can typically operate in different modes and with different settings of several parameters. Also, especially for refrigeration systems used for food storage, the system may be configured to transmit an alarm when the system is not performing according to the user requirements. Accordingly, the control units are often programmed to have an extensive software menu for delivering system information and receive user input. As the user interface is commonly very simple as described above, retrieving information and setting up a refrigeration or air-conditioning system may be a tedious and time consuming process. DESCRIPTION OF THE INVENTION
It is an object of embodiments of the invention to provide a controller for thermal process control, with a versatile and user friendly user interface without adding significantly to the manufacturing cost of said controller. According to a first aspect, the invention provides a controller for a refrigeration system, the controller comprising a housing encapsulating computer means for processing data, data storage means for storing data, a data interface for communicating data with the
refrigeration system, and a front surface comprising a user interface for communication with a user, the user interface comprising a digital visual output unit and a touch sensing area, wherein the digital visual output unit is incorporated into a first portion of the front surface on the housing, and the touch sensing area is incorporated into a second portion of the front surface, the first portion being distinct from the second portion, the touch sensing area being in the form of an inductive sensor or a capacitive sensor.
The controller according to the first aspect of the invention is configured to control a refrigeration system. In present context the term "refrigeration system" should be interpreted to mean any system providing cooling power utilizing a vapor compression system such as a refrigerator, a freezer or an air-conditioning module.
The controller provides a user interface comprising a digital visual output unit and a touch sensing area, wherein the touch sensing area is in the form of an inductive sensor or a capacitive sensor, and the digital visual output unit and touch sensing area are placed separately in a non-overlapping manner on the front surface of the controller. In this case, the digital visual output unit may not be covered by the user during operation of the touch sensing area. This is of particular importance in refrigeration system controllers, where digital visual output units are often relatively small and where the user would otherwise have difficulty retrieving information while delivering input to the controller.
The touch sensing area may be able to register tapping and swipe gestures, where a correctly registered swipe may result in movement of all or some of the content of the digital visual output unit according to the registered swipe.
A capacitive touch sensor capable of registering tapping and swipe gestures allows more versatile and rigorous user inputs than with tactile switches usually present on controllers for refrigeration systems. Even on a relatively small touch sensing area, swipes can be consistently delivered . This is because only the direction of the moving touch within the touch sensing area matters, as opposed to the case where user input is done via small, closely packed buttons.
The touch sensing area may comprise at least four capacitive sensor fields, such as five or nine capacitive sensor fields, where a touch on one capacitive sensor field followed by a touch on an adjacent capacitive sensor field is registered as a swipe. According to this embodiment, the touch sensing area may have resolution of nine pixels. This is sufficient for registration of both longitudinal and vertical swipes along the touch sensing area, while allowing registration of two swipes along the same direction with one touch . A touch sensing area with nine capacitive sensor fields thus provides versatile input options, while adding a bare minimum to manufacturing costs due to the very simple design.
The controller may also comprise a menu system, which may be programmed to be navigated by the touch sensing area. Modern refrigeration systems often have extensive configuration possibilities and a large number of parameters to be set and read off by the user. As a consequence, it is often desirable to program the controller with a menu system. A touch sensor area which may be enabled with tapping and swiping registration is particularly useful for navigating a menu system found in many modern controllers.
The controller may be configured with the digital visual output unit and the touch sensing area separated by a distance equal to or greater than half the width of the digital visual output unit. Front surfaces of modern day controllers are often subject to a market standard of 29 ± 0.5 mm x 71 ± 0.5 mm. It can therefore be challenging to operate the touch sensing area without blocking the view of the digital visual output unit. In this case it may be an advantage to separate the touch sensing area and the digital visual output unit at least by a distance equal to half the width of the digital visual output unit.
The controller may be configured with the digital visual output unit and the touch sensing area being separated by a distance equal to or smaller than twice the width of the digital visual output unit. In order to ensure simultaneous visibility of the digital visual output unit and the touch sensing area, it may be an advantage to separate them by a distance no longer than twice the width of the digital visual output unit.
The controller may be configured with the digital visual output unit in the form of a digital visual output unit with alphanumerical and/or graphical symbols. To further minimize the manufacturing cost of the controller it may be an advantage to use as simple a digital visual output unit as possible, while allowing adequately detailed information to be displayed by the digital visual output unit. Accordingly, the alphanumerical symbols may comprise segmented displays, with at least two segments, such as seven segment displays. The controller may be configured with an element of electrically conducting material establishing at least part of an electrically conducting path from the inductive or capacitive touch sensing area on the front surface of the controller to a printed circuit board placed in the controller unit in a manner so that the printed circuit board is not exposed to the front surface of the controller.
As controllers may be exposed to water and cleaning processes, the front surface of controllers are usually provided with a water tight seal. A touch sensing area on the front surface of the controller should thus also be water tight. Most controllers are provided with a flat printed circuit board, whereon the digital visual output unit is directly mounted . The digital visual output unit thus extrudes from the printed circuit board . In present invention, the printed circuit board may be configured with capacitive or inductive sensors. Thus, in order to provide a flat front surface of the controller, while also providing an electrical connection between the touch sensing area and the capacitive or inductive sensors on the printed circuit board, an element of electrically conducting material between the touch sensing area and the printed circuit board is needed .
The element of electrically conducting material may be an injection moulded element.
Injection moulded electrically conducting materials can have very low manufacturing costs. Thus, utilizing injection moulding to manufacture the element of electrically conducting material can further minimize the cost of manufacturing the controller. The element of electrically conducting material may extend to areas on the front surface of the controller other than the touch sensing area . According to this embodiment, the element of electrically conducting material may extend to areas on the front surface of the controller not part of the touch sensing area. This may be an advantage in the manufacturing process.
According to a second aspect, the invention provides a method for manufacturing a controller, wherein the front surface is manufactured using injection molding. Injection molding is often a relatively low cost manufacturing process. Thus, by utilizing injection molding to manufacture the entire front surface of the controller, including the touch sensing area, can further minimize controller manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in further detail with reference to the accompanying drawing in which
Fig. 1 is a drawing of a controller according to an embodiment of the invention . Fig. 2 is a drawing of a controller according to an embodiment of the invention . DETAILED DESCRIPTION OF THE DRAWINGS
Fig. 1 is a drawing of a controller 1 according to an embodiment of the invention viewed from a front-side perspective. The controller comprises a housing 2 encapsulating computer means for processing data, data storage means for storing data, a data interface for communicating data with a refrigeration system and a menu system. The controller also comprises a front surface 3, digital user output unit 4 and a touch sensing area 5 comprising nine capacitive sensor fields 6 corresponding to nine capacitive sensors 7.
The front surface 3 is build from two parts: an essentially transparent polycarbonate part 8 and an element of electrically conducting material 9. Together, the two parts form a water tight front surface 3 making it resistant to water splashes experienced during cleaning. On the polycarbonate part 8, the touch sensing area 5 is separated from the view area 10 corresponding to the area defined by the visual output unit 4. In this case, the digital visual output unit 4 will not be covered by the user during operation of the touch sensing area 5. This is of particular importance in refrigeration system controllers, where digital visual output units 4 are often relatively small and where the user would otherwise have difficulty retrieving information from the digital visual output unit 4 while delivering input to the controller 1.
The touch sensing area 5 according to this embodiment is able to register tapping and swipe gestures, where a correctly registered swipe will result in movement of all or some of the content of the digital visual output unit 4 according to the registered swipe. Even on a relatively small touch sensing area 5, swipes can be consistently delivered . This is because only the direction of the moving touch within the touch sensing area 5 matters, as opposed to the case where user input is done via small, closely packed buttons. This is particularly useful when the controller 1 comprises a menu system, as navigating a menu system requires consistently delivered user input. According to this embodiment the element of electrically conducting material 9 and polycarbonate part 8 are both manufactured using injection molding. As injection molding is usually a cost and time effective manufacturing method, the manufacturing cost of the controller according to present embodiment is kept at a minimum.
Fig. 2 is a drawing of the same controller 1 according to the embodiment of the invention described with reference to Fig. 1. Here with a rear view of the polycarbonate part 8, the element of electrically conducting material 9 and the controller housing 2. The element of electrically conducting material 9 is not necessarily transparent and is configured with an opening 11 in the area corresponding to the view area 10 and visual output unit 4 visible in Fig. 1. The element of electrically conducting material 9 is also configured with nine conducting elements 12. In an assembled controller 1, these nine conducting elements 12 each extend from just behind the polycarbonate part 8 to the nine capacitive sensors 7 visible in Fig . 1. The nine conducting elements 12 are in an assembled controller 1 separated from etch other by barriers 13 defined in the polycarbonate part 8. In the touch sensing area 5, the polycarbonate part 8 is thin enough to allow an appropriate touch in this area to result in a capacitive change to be registered by the capacitive sensors 7, via the nine conducting elements 12. Thus, the touch sensing area 5 has nine pixels in the form of nine capacitive sensor fields 6, each uniquely associated with a capacitive sensor 7.