System and method for configuring a display for a digital multimeter
Contents
1. 806 If during step 804 the application processor determines that the default function was previously used in the switch posi tion in step 812 the processor will revert back to the default function Then the multimeter will continue to step 806 in which the multimeter determines whether a mode was enabled previously in the switch position If a mode was enabled previously in the switch position in step 807 the processor will enable the previous mode Then the applica tion processor will continue to step 808 in which the proces sor performs the measurement function and step 809 in which the measurement value and prescribed mode will displayed If during step 806 the application processor determines that no mode was previously enabled in step 808 the processor will perform the measurement function and in step 809 the processor will display the measurement value After complet ing step 809 the application processor will determine whether the rotary switch has been moved and will return to step 801 Dynamically Generated Status Bar Providing Live Measure ment Reading Digital multimeters commonly are used to perform rela tively simple measurements of voltage current resistivity or other circuitry parameters When used for this purpose the instrument typically displays the measured value in a promi nent manner on a display screen to apprise a user of the measurement result As discussed above more sophisticated digital multim et2. FIG 10 illustrates a flow diagram for dynamically gener ating the status bar display in accordance with an exemplary 20 25 30 35 40 45 50 55 60 65 10 embodiment In step 1002 the application processor detects that a mode was selected In step 1004 the application pro cessor retrieves display parameters from memory corre sponding to the selected mode Specifically the display parameters detail whether the main display area continues to include the live actual measurement If in step 1006 it is determined that the live actual measurement was removed in step 1008 the status bar on the display is dynamically re configured to include the live actual measurement with a reduced font size as a mini measurement If the live actual measurement was not removed then the system waits until a new mode has been selected In step 1010 the processor retrieves from memory a thresh old value that was configured by the user or otherwise pro grammed into memory If in step 1012 the threshold value associated with the live actual measurement has been exceeded in step 1014 a lightening bolt warning icon is included in the status bar area and the system then determines whether a new mode was selected in step 1016 Accordingly the exemplary embodiment provides inte grated capability to dramatically improve the safety associ ated with use of a digital multimeter with potential high voltage or high curr
3. Sheet 3 of 11 US 7 626 375 B2 100 Jan 18 2006 U S Patent Dec 1 2009 Sheet 4 of 11 US 7 626 375 B2 100 Ga 8 40 pm 03 13 06 gt 26 594 Auto Range 0 mVDC 105 136 ad 144 U S Patent Dec 1 2009 Sheet 5 of 11 US 7 626 375 B2 100 26 554 105 z Auto Range 50 mVoCc 504 Temp O REL O Hz ms O Peak 111 O Probe F aa AC DC 112 136 144 134 121 122 123 124 FIG 5 U S Patent Dec 1 2009 Sheet 6 of 11 US 7 626 375 B2 100 RANGE o info he 144 121 122 123 124 FIG 6 U S Patent Dec 1 2009 Sheet 7 of 11 US 7 626 375 B2 100 702 U S Patent Dec 1 2009 Sheet 8 of 11 US 7 626 375 B2 Detect new position of rotary switch RSM enabled Retrieve data from memory for switch position 812 Change 811 Default measurement from default Default measurement function Change measurement function away from default Mode enabled Yes 807 Enable mode 808 Perform measurement 809 Display FIG 8 Yes Detect rotation in rotary switch U S Patent Dec 1 2009 Sheet 9 of 11 US 7 626 375 B2 904 08 10 pm Jan 18 2006 4 123 45 VAC 902 1 3 684 cons Auto Range 400 VAC 121 22 VAC FIG 9 U S Patent Dec 1 2009 Sheet 10 of 11 US 7 626 375 B2 Retrieve display parameters for the selected Live actual measurement New mode selected remo
4. blocks are at times shown as being performed in series these processes or blocks may instead be performed in parallel or may be performed at different times The teachings of the invention provided herein can be applied to other systems not necessarily the system described above The elements and acts of the various embodiments described above can be combined or altered to provide further embodiments 20 25 30 35 40 45 50 55 60 65 14 These and other changes can be made to the invention in light of the above Detailed Description While the above description describes certain embodiments of the invention and describes the best mode contemplated no matter how detailed the above appears in text the invention can be prac ticed in many ways Details of the system may vary consid erably in its implementation details while still being encom passed by the invention disclosed herein The terminology used in the Detailed Description is intended to be interpreted in its broadest reasonable manner even though it is being used in conjunction with a detailed description of certain specific embodiments of the invention Certain terms may even be emphasized however any termi nology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section In general the terms used in the following claims should not be construed to limit the inven tion
5. same context In other words once the user has scrolled to a certain position in the information dialog he may toggle between the underlying screen and the information dialog without losing his place in the information dialog For instance if the user presses Info button 128 while measur ing Volts AC the information dialog can pop up displaying the first topic listed in the information dialog Then if the user scrolls down the information dialog to the fourth listed topic toggles back to the original screen and subsequently back to the information dialog the information dialog will display the fourth listed topic The overview information displayed when Info button 128 is pushed can be available in a variety of languages The overview information can be stored in compressed format to minimize the storage requirements providing more capacity for storing measurement information Referring to FIG 3 the Info button 128 is part of the keys button input 350 that is electrically connected to Appli cation Processor 322 When a user depresses this key the Application Processor 322 retrieves information about the context from memory 330 concerning the Info button 336 More specifically the Application Processor queries the memory for data to provide to the display 300 based upon the context oficons modes and other information relevant to the present display Accordingly the exemplary embodiment provides inte grated capability to dr
6. 22 receives input relating to measurement applications including the rotary switch input 240 and the variety of keys and buttons 250 on the face of the multimeter The applications processor 222 also retrieves data from various databases in memory 230 and provides output to display 200 The applications processor may be one presently available from Freescale as an ARM processor Memory 230 can be any combination of RAM ROM DRAM Flash EPROMs EEPROMs or any other semicon ductive memory chip The memory may be comprised within one chip or may be distributed among a plurality of chips or databases The memory 230 stores information relating to the various measurement functions 231 e g V AC V DC ohms etc and modes 232 e g auto save relative as both were described above as well as information pertaining to rotary switch measurement mode programming 233 status bar mini measurement display 234 threshold values 235 and the Info button 236 as will each be described below in further detail Rotary Switch and Rotary Switch Memory FIGS 1 7 illustrate screens associated with repositioning rotary switch 120 FIG 1 illustrates a screen in which Volts AC 132 has been selected by toggling rotary switch 120 to position 132 The screen displays the measured voltage 123 45 VAC 102 FIG 3 illustrates a screen that can appear after Max Min mode has been selected by pressing MIN MAX button 126 The screen displays the measured vol
7. a measurement value for memory storage and later retrieval Accordingly digital multimeters incorporate various tools for performing different types of measurements and different capabilities for displaying measurement values in a digital format on a screen Further capabilities and improvements are needed however in both hardware and software to enable users to organize measurement information to be obtained by the instrument so as to operate the instrument efficiently effectively and safely BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 illustrates a front face of a digital multimeter inte grating a rotary switch various soft keys and buttons and an LED screen to provide highly configurable multimeter operation in accordance with an exemplary embodiment FIG 2 is a schematic layout of the circuitry and compo nents of which the digital multimeter of an exemplary embodiment is comprised FIG 3 illustrates a screen that can appear after Max Min mode has been selected FIG 4 illustrates a screen in which mVDC has been selected 20 25 30 35 40 45 50 55 60 65 2 FIG 5 illustrates an example ofa function and mode menu FIG 6 illustrates a screen displaying a value for a measured temperature FIG 7 illustrates a screen that can appear after a user selects Min Max mode by pressing MIN MAX button while in the screen shown in FIG 6 FIG 8 illustrates a flow diagram for the procedure followed by th
8. a user can switch from topic to topic using navigation buttons 114 117 The topics shown may be listed in order of relevance to the topic When the user is uncertain about an operation or visible element appearing in the display the user can push Info button 128 to learn about the operation or visible element appearing in the display The user can navigate forward and backward between indi vidual topics as well as between pages Soft Key 110 can be set to select Next 1112 which moves to the next topic entry for the screen By pressing soft key 110 and looking at the icons the user can move fairly rapidly to the topic of interest Soft key 110 can be programmed to become disabled once the last topic is reached in the information dialog Soft key 111 can be programmed to select Prev 1114 which causes screen 1100 to move to the previous topic entry for the screen Soft key 111 can be programmed to become disabled once the first topic is reached in the information dialog Soft Key 112 can be programmed to operate to select More 1116 which allows the user to scroll down the information one page at a time ignoring topic boundaries Selecting More 1116 can provide a way for the user to continue reading the text accompanying an icon for a topic when only a portion of the text is shown on the display Soft key 112 can be programmed to become disabled once the end ofa topic is reached The down navigation button can p
9. amatically improve the operability of a digital multimeter that incorporates various feature measure ment functions and modes By dynamically generating text on the display that corresponds to the present display context a user can instantly learn about the capabilities of the instru ment without having to refer to a separate user manual The presentation of the requested information is tailored for the small LCD screen provided on the instrument Because the multimeter is intended to be portable and self contained it is otherwise highly inconvenient to separately carry a user manual Further experienced technicians or other users may be unlikely to tote a user s manual but would benefit from gaining instant information concerning the capability of a particular feature associated with an icon on the display By incorporating this functionality with the soft buttons naviga tional buttons and other forms of user input a user can easily navigate the vast glossary of information concerning the device to find the desired information quickly and efficiently US 7 626 375 B2 13 As another unique aspect of incorporating the Info button on the instrument a company can re program or tailor the presentation of information from the Info button to corre spond to particular company procedures or processes associ ated with measuring electrical circuits This highly innova tive feature provides a particular unforeseen benefit in the context
10. ay be used in place of a dedicated button In accordance with the exemplary embodiment when Info button 128 is pressed explanatory information provid ing an overview of the functionality of the icons and other information on the display can be displayed as a pop up information dialog overlying most of the screen The infor mation displayed may vary according to the context at the time Info button 128 was pressed For example the Info button 128 may be pushed by a user to receive additional information concerning any of Measure Volts DC Mea sure Volts AC Measuring Crest Factor Measuring Duty Cycle Recording Measurements and Choosing a Mea surement Function Since the context can vary with the posi tion of the rotary switch and other possible soft key choices the information displayed can vary according to these selec tions US 7 626 375 B2 11 Each screen menu and dialog potentially can have a cor responding information dialog When a menu is present on the screen the selected item on the menu can determine the context for the informational dialog Alternatively all of the menu items can determine the context for the informational dialog Some topics may include instructions for using a function or examples of applications in which a user could employ certain functionality available on the instrument For example a topic could explain what a certain mode of mea suring is and wh
11. az United States Patent US007626375B2 10 Patent No US 7 626 375 B2 Garland et al 45 Date of Patent Dec 1 2009 54 SYSTEM AND METHOD FOR CONFIGURING 56 References Cited A DISPLAY FOR A DIGITAL MULTIMETER U S PATENT DOCUMENTS 75 Inventors Anthony C Garland Camano Island 5 218 290 A 6 1993 Beckertetal 324 115 WA US Joseph Victor Ferrante Redmond WA US Brian Michael FOREIGN PATENT DOCUMENTS Capoccia Seattle WA US Lindsey EP 0504514 A 9 1992 Berdan Seattle WA US Bradey JP 2001 311747 A 11 2001 David Honsinger Everett WA US Jeffrey William Meyer Seattle WA OTHER PUBLICATIONS US EP Search Report European Application No 08162447 0 1524 Applicant Fluke Corporation Mailed Nov 19 2008 24 pages 73 Assignee Fluke Corporation Everett WA US i cited by examiner Notice Subject to any disclaimer the term of this Primary Examiner Ha Tran T Nguyen patent is extended or adjusted under 35 Assistant Exainin r Roberto Velez U S C 154 b by 0 days 74 Attorney Agent or Firm Perkins Coie LLP 21 Appl No 11 838 881 57 ABSTRACT 22 Filed Aug 14 2007 A digital multimeter with a rotary switch having a plurality of A aor positions each of the positions corresponding to a primary 65 Prior Publication Data measurement function to be performed An LCD displays US 2009 0045800 Al Feb 19 2009 secondary functions or modes corresponding to the positions ofthe rotary sw
12. cedures may include steps which require the user to rotate the switch 120 to a new function to perform a measure ment It is possible to switch measurement functions within the context of a procedure When RSM is on rotating the switch will not effectively reset the state of multimeter 100 which will prevent multimeter 100 from losing its place in the procedure Even when multimeter 100 is turned off and back on if a procedure was active at the time it was turned off multimeter 100 can resume at the previous step within the procedure If rotary switch 120 has changed position while multimeter 100 was off the user can be prompted to move rotary switch 120 back to the correct position in the procedure in order to continue The user can also elect to cancel the procedure which was in progress Since a user may only use particular settings that are dif ferent from the defaults RSM can always be enabled in some embodiments so that these users do not inadvertently disable RSM and lose all of their settings When RSM is always enabled there will be no way to disable RSM In these embodiments the user may be required to manually change every setting or the user may be able to simply push a button to restore defaults If the user restores a default for a position RSM will remember the default every time the user returns to that position unless the user changes the settings Rather than RSM being constantly enabled for all positions of rotary swi
13. ction buttons or dedicated buttons or soft key buttons corre sponding to display 105 Output can be presented to the user with the display 105 an indicator light and or an audible beeper Multimeter 100 can include an internal memory for storing information such as measurement values Soft keys 110 113 can be located in an area beneath the display 105 and positioned to correspond with labels 106 109 on the display Pressing one of the soft keys 110 113 invokes the command indicated by the corresponding label on the display Every screen has a custom set of soft key labels 106 109 Some screens have fewer labels than soft keys When a soft key does not have a corresponding label that soft key is disabled For example in the screen shown in FIG 1 Menu 150 corresponds with soft key 110 Save 152 cor responds with soft key 111 Setup 154 corresponds with soft key 113 and soft key 112 does not have a corresponding label Navigation buttons 114 117 can be centrally located among the other buttons of multimeter 100 Navigation but tons 114 117 correspond to four cardinal directions UP 115 DOWN 117 LEFT 114 and RIGHT 116 Naviga tion buttons 114 117 are used to move within menus and dialogs and to make choices and perform data entry They can also be used to scroll through a sequence of information too extensive to be displayed on a single screen Info button 128 can provide access to context sensitive in
14. e multimeter when the rotary switch is moved to a new position FIG 9 illustrates a screen in which a mini measurement informs the user of the live reading while display is frozen with a past reading on hold FIG 10 illustrates a flow diagram for dynamically gener ating the status bar display in accordance with an exemplary embodiment FIG 11 illustrates an example of an information glossary configured for display on an LCD screen on a digital multi meter in accordance with an exemplary embodiment DETAILED DESCRIPTION An inventive digital multimeter instrument and inventive methods for operating a digital multimeter are disclosed below in detail In particular the digital multimeter as described herein incorporates a rotary switch a series of keys and buttons and a digital display so as to provide highly integrated programmable and configurable features not available on conventional multimeters Several of these fea tures either taken alone or in combination provide signifi cant improvements in ease of use speed of user operation and safety associated with use of the instrument The modi fications alterations and additions to conventional multim eters that were necessary to accomplish these features resulted in benefits that otherwise would not have been fore seen or appreciated by others skilled in the art Description of Components in a Highly Integrated Multim eter Instrument A face for an exemplary multime
15. ed mea surement setting from the memory and associates the position of the rotary switch with the modified measure ment setting in the place of the default measurement function 2 The digital multimeter of claim 1 wherein the multim eter is configured to continue to store the modified settings in the memory after power to the multimeter is discontinued 3 The digital multimeter of claim 1 wherein the settings comprise a mode 4 The digital multimeter of claim 1 wherein the modified measurement setting comprises a measurement function that is different from the default measurement function 5 The digital multimeter of claim 4 wherein at least one position is associated with a default measurement function and an alternative measurement function and the setting is changed to toggle to the alternative measurement function 6 The digital multimeter of claim 1 wherein the processor is configured to be disabled from modifying settings upon receiving user input to return all settings to default measure ment functions US 7 626 375 B2 15 7 A digital multimeter comprising arotary switch having a plurality of positions wherein for a plurality of positions on the switch the position on the switch corresponds to a default measurement function a user interface configured to receive 1 an alternative measurement function selection and 2 an enable command a processor configured in response to an alternative mea suremen
16. en one would use it As additional function ality the multimeter can be programmed by the user to include certain topics in certain contexts For instance a company may have a particular procedure for taking mea surements in a building The company could program the information dialog to show instructions for their procedure This way the operator only needs to carry the multimeter when performing the procedure The overview information can be programmed to eventu ally disappear after a set amount of time or after a certain event Once the overview information disappears the under lying information on the screen prior to the appearance of the dialog can be restored An example of a screen 1100 having an informational dialog that can be provided in response to a user pressing Info button 128 is shown in FIG 1 Since overview infor mation obscures the current measurement a miniscale mea surement 1104 can be provided A title bar 1106 can indicate the context in which Info button 128 was pressed In the example of FIG 11 the context is measuring volts DC A list of specific topics can be provided below the title bar 1106 Each topic can be related to the context in which Info button 128 was pressed Each topic can be associated with an icon 1108 and a brief explanation 1110 of the subject Icon 1108 provides an easy way for the user to quickly identify a topic Additionally icon 1108 can provide an anchor for each topic so that
17. ent circuitry By dynamically re config uring the status bar area display the multimeter can include extra measurement data when needed but remove this infor mation from an already crowded display area when the data otherwise would be redundant Additionally the exemplary embodiment includes a warning icon such as a lightening bolt to notify a user when the live actual measurement has exceeded a threshold value that could affect the safety of the user By positioning this indicator in the status bar area the user can quickly and efficiently check whether there are safety issues of concern without otherwise disrupting the measurements in progress Information Screens Operators using multimeters on work sites rarely carry an instruction manual for the instruments with them from loca tion to location However as multimeter instruments have been increasingly complex and incorporate a wide variety of features it is often helpful to have such a guide while taking measurements Particularly the operator may not remember what a certain icon represents or in which application a function can be used Referring to FIG 1 in the exemplary embodiment selecting Info button 128 provides the user an overview of all the operations and visual elements appearing in the display Although the example in the ensuing discussion provides for a dedicated button as a user input for requesting genera tion of an information screen other forms of input m
18. epresented with US 7 626 375 B2 3 out changing the measurement function Min Max Hold Range Peak and Record are examples of modes that can operate in conjunction with the measurement function Min Max is a mode in which the multimeter displays the live minimum maximum and average measurements that have occurred from the time the initial measurement of a parameter began In other words whenever a new maximum or minimum occurs exceeding the previous maximum or minimum the new value is stored Hold is a mode in which a displayed value is frozen on the display Range is a mode in which the range or resolution of the displayed value is specified by user input Recording is the automatic sav ing of a sequence of measurements of a single parameter over a period of time for future review or storage As examples a resistance measurement can be recorded using the record mode User Input Devices Rotary Switch Buttons and Keys As will now be described multimeter 100 in accordance with an exemplary embodiment can include a rotary switch 120 a set of navigation buttons 114 117 a set of soft keys 110 113 an on off switch 118 a backlight control button 119 and an Info button 128 Additionally multimeter 100 can include dedicated mode buttons including HOLD 125 MIN MAX 126 and RANGE 127 buttons A user can configure the device as desired by utilizing multi fun
19. er selects Min Max mode by pressing MIN MAX button 126 while in the screen shown in FIG 6 The screen displays the measured voltage 26 5 C 702 the maximum measure ment value 704 the average measurement value 706 and the minimum measurement value 708 Each of the maximum average and minimum measurement values include an optional time stamp 710 denoting how much time has elapsed when the measurement values were detected The multimeter can include rotary switch memory which is a memory that stores functions and modes for individual rotary switch positions Rotary switch memory RSM can be configurable in the setup screen in which it can be turned on or off The setup screen appears when setup 156 is selected by pressing soft key 113 in FIGS 1 3 5 and 6 For example when RSM is off and functions and or modes are set in a first position of rotary switch 120 in FIG 1 multimeter 100 restores default functions and modes once rotary switch 120 is moved to another position With RSM disabled multimeter 100 will not remember the settings once rotary switch 120 is returned to the first position However multimeter 100 can remember the settings when multimeter 100 is turned off if rotary switch 120 remains in the same position when multi meter 100 is turned back on In other words due to a non volatile memory multimeter 100 can continue to have the same settings when multimeter 100 is turned off or the bat teries are taken ou
20. erform the same function as soft key 112 when the information dialog is present The up navigation button can perform that opposite function of the down navigation button and soft key 112 when the information dialog is present In other words the up navigation button can be programmed to provide a way to 20 30 35 40 45 50 55 60 65 12 scroll up the information on the display The left and right navigation buttons can be disabled when the information dialog is present Soft key 113 can be programmed to select Close 1118 which closes the information dialog once soft key 1111 is pressed There are various other ways the information dialog can be prompted to close For instance the user can close the information dialog by pressing Info button 128 while the information dialog is present The information dialog may also be closed by turning the rotary switch to a new position or pressing the on off button or a dedicated mode button Info button 128 can be pressed in any context Title bar 1106 can reflect the context within which the button as pressed Examples of contexts can include Measure Volts DC Measure Volts AC Measuring Crest Factor Measuring Duty Cycle Recording Measurements and Choosing a Mea surement Function The information dialog can include a scrolling memory that remembers where in the information dialog the user last scrolled during a previous viewing of the information dialog in the
21. ers include capabilities to display measurement information beyond simple measurement values relating to one or more different measurement modes For selection of at least some of these modes the resulting measurement value dis played on the instrument is no longer the actual value of the voltage current or resistivity across a node in a circuit Instead the displayed value corresponds to a different char acteristic of the actual measurement associated with the selected mode As an example when a multimeter is placed into the rela tive mode the instrument is configured to display measure ment related information concerning how far above or below the actual live measurement is from some reference value For instance if this mode is selected and configured for a refer ence value of 200V AC the display generates information concerning how far above or below the actual measurement is from 200V AC instead of displaying the actual measurement itself Therefore continuing with this example if the actual measurement is 205V AC the display will indicate 5 V AC As another example the selection of a low pass filter mode provides a displayed value that is based upon a filtered value which may be significantly different from the actual live value being measured As an unfortunate consequence of utilizing different modes when operating a multimeter instrument a user may easily be lulled into a misperception that the multim
22. eter dis play is reporting an actual live measurement reading As an example while the relative mode is selected a user may mistakenly believe that the 5V AC reading reports an actual live measurement instead of being a 5V AC deviation from a 200V AC reference voltage value In some situations such a misperception could prove to be hazardous to the operator of the instrument In an exemplary embodiment of a digital multimeter an additional display value is provided as a live measurement value to ensure that a user can discern the live actual mea US 7 626 375 B2 9 surement However because a portable handheld multimeter incorporates a very small digital screen displaying this value could tend to overcrowd the display or otherwise confuse the user There thus exists a tension between the advantages of displaying the live actual measurement prominently for safety considerations and arranging the display in a manner for easy use with a quick glance at the instrument In accordance with the exemplary embodiment a digital multimeter includes a dynamically generated status bar area that provides in a single predictable area dynamically selected information believed to be of significance to a user As shown in FIG 1 the status bar may often or always include for example a battery strength indicator 158 the time 160 and date 162 and some indication of the instrument setting speaker set on 164 Additionall
23. formation about the measurement function and display con tents Further details regarding Info button 128 are dis cussed below The context sensitive information may appear as a pop up informational area which overlays most of the underlying screen Multimeter 100 can include a backlight for the display 105 to allow improved viewing in conditions of reduced light The backlight is activated by backlight control button 119 Mul timeter 100 can also include an On Off button 118 used to turn multimeter 100 on or off Tn accordance with an exemplary embodiment each posi tion of rotary switch 120 corresponds to at least one different primary function Rotary switch 120 includes positions 130 132 134 136 138 140 142 144 146 and 148 The func tions are indicated by symbols surrounding rotary switch 120 20 30 40 45 50 55 60 65 4 Rotary switch 120 can include functions such as AC voltage measurement from 0 V to 1000 0 V AC millivolt measure ment from 0 mV to 3000 0 mV DC voltage measurement from 0 V to 1000 0 V DC millivolt measurement from 0 mV to 3000 0 mV resistance measurement from OQ to 500 0 MQ capacitance measurement from 0 001 nF to 50 mF tempera ture measurement AC current measurements from 0 mA to 20 000 A AC current measurements from 0 uA to 5000 0 uA DC current measurements from 0 mA to 20 000 A DC cur rent measurements from 0 uA to 5000 0 uA In addition to a primary function each p
24. i measurement can display the primary function that the secondary function is derived from if the primary function is not displayed elsewhere on the screen In some embodiments the exemplary multimeter is configurable for setting a condition that prompts the mini measurement to appear As an additional safety feature the mini measurement can be accompanied by a mini lightning bolt mini bolt if display 105 is displaying a Volts AC or DC function and a potentially hazardous voltage is present This triggering value may be user configurable or it may be factory programmed For instance the mini bolt could be set to appear when the voltage reading is at or above 30 VAC In some embodiments the user can set the minimum voltage or other condition triggering the mini bolt to appear and can alter a factory programmed value In some embodiments primary readings may be accompa nied by a comparatively larger lightning bolt not shown when a potentially hazardous voltage has been measured or multimeter 100 is being calibrated If the mini bolt is dis played and a larger lightning bolt accompanying the dis played reading is obscured the mini measurement the mini bolt or both may blink Additionally the mini measurement may blink when high current is present in the A and mA functions to warn the user that the fuse may eventually fail In some embodiments the user may be able to set a condition that prompts mini bolt to appear and or to blink
25. imary measurement US 7 626 375 B2 5 Schematic Layout of Multimeter Circuitry and Components FIG 2 is a schematic layout of the circuitry and compo nents of which the digital multimeter 100 of an exemplary embodiment is comprised As shown the multimeter includes a digital display 200 a power source 210 controllers and processors 220 a memory section 230 and three input types 240 250 and 260 As described above the display 200 can be an LCD dis play and is generally characterized as having a relatively small footprint of approximately 6 8 square inches The dis play 200 includes an area for a status bar 201 near an upper portion and an area for defining soft keys at a bottom portion as will be described below The display 200 is electrically connected to the controllers processors 220 to receive data to output and to power source 210 to receive electrical power As a portable system power source 210 can be comprised of batteries such as 4 AA alkaline batteries or it can incor porate an AC adapter to receive power from a standard AC electrical outlet The power source is connected to the display 200 the controllers processors 220 and memory 230 The controllers processors include at least two processors in the exemplary embodiment In particular input from elec trical leads 260 are provided to a measurement processor 221 This may be a processor presently available from Texas Instruments The applications processor 2
26. itch and values determined by performing one 51 Int Cl of the measurement functions The multimeter includes GOIR 1 38 2006 01 default functions for each position of the rotary switch that GOIR 11 57 2006 01 may be changed to other functions or modes When the other GOIR 15 00 2006 01 functions or modes are set in a first position the rotary switch GOIR 15 08 2006 01 is moved to a second position and returned to the first posi GOIR 7 00 2006 01 tion the multimeter restores the functions and or modes set 52 US Gls Hee et a Senin 324 115 324 141 when the rotary switch was previously in the first position 58 Field of Classification Search 00 0 000 None See application file for complete search history ee 9 Claims 11 Drawing Sheets 158 160 162 164 ae 8 10 pm 03 43 06 s 1123 45 Auto Range 500 VAC 144 121 122 U S Patent Dec 1 2009 Sheet 1 of 11 US 7 626 375 B2 100 1423 45 Auto Range 500 VAC 136 es 144 U S Patent Dec 1 2009 Sheet 2 of 11 US 7 626 375 B2 210 Display Status Bar Power Source Soft Keys Area 230 Controllers Processors Memory a 222 Measurement Application Processors Functions 232 221 Modes 233 Rotary Switches 240 250 234 260 Rotary Switch Input Keys Buttons Input Cones at Status Bar 235 Threshold Values 236 Info Button FIG 2 U S Patent Dec 1 2009
27. lly return to the screen of FIG 1 If the RSM function is enabled and rotary switch 120 is toggled back to position 132 while in the screen shown in FIG 7 and then returned again to position 138 the multim eter will automatically return to the screen shown in FIG 7 If the RSM function is disabled and rotary switch 120 is toggled back to position 132 while in the screen shown in US 7 626 375 B2 7 FIG 7 and then returned again to position 138 the multim eter will automatically return to the screen shown in FIG 4 In some embodiments certain modes may not ever be affected by RSM For instance to comply with safety stan dards low pass filter mode may not be remembered by mul timeter 100 Low Pass Filter is a mode in which a filter passes low frequencies but reduces frequencies higher than a cutoff point A potentially dangerous situation could be one in which a user forgets that the multimeter is in low pass filter mode and mistakenly believes that the low pass filter reading is the live reading In this situation the user may be injured by touching live connections that he believes to be safe To prevent this situation low pass filter can be excluded from the modes affected by RSM in which case the user will be forced to set multimeter 100 to low pass filter mode every time this mode is desired It is contemplated that a multimeter can allow the user to set which functions and modes may or may not be affected by RSM Pro
28. nction including any selected secondary function or modes When rotary switch is turned from one function to another a display for the new function appears on display 105 In some embodiments button choices made in one function do not carry over into another function Analog connections on input jacks 121 124 can be used to provide input to be measured by multimeter 100 As shown in the example of FIG 1 four input jacks 121 124 can be included along the bottom of multimeter 100 where the user connects input probes used to measure signals of interest Output can be presented to the user with the display 105 an indicator light and or an audible beeper Multimeter 100 can include an internal memory 204 for storing information such as measurement values Multimeter User Display As shown in FIG 1 digital multimeter 100 includes a display 105 which may be an LCD screen or any other suitable type of display In the illustrated embodiment the rotary switch 120 in FIG 1 is set to the V AC position and so the display 105 exhibits a V AC primary measurement 134 As depicted in the figure the measurement may be displayed in a bold type and or in a comparatively larger font size in relation to other displayed measurements to indicate which measurement is the primary measurement Display 105 may further exhibit a secondary measurement which is a measure ment on the display representing an additional function shown concurrently with the pr
29. not limited to Additionally the words herein above below and words of similar import when used in this application shall refer to this appli cation as a whole and not to any particular portions of this application Where the context permits words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively The word or in reference to a list of two or more items covers all of the following interpretations of the word any of the items in the list all of the items in the list and any combina tion of the items in the list The above detailed description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above While specific embodiments of and examples for the invention are described above for illustrative purposes various equivalent modifications are possible within the scope of the invention as those skilled in the relevant art will recognize For example while processes or blocks are presented in a given order alternative embodiments may perform routines having steps or employ systems having blocks in a different order and some processes or blocks may be deleted moved added subdivided combined and or modified to provide alternative or subcombinations Each of these processes or blocks may be implemented in a variety of different ways Also while processes or
30. of a digital multimeter since it can be used by a fleet of mobile technicians at remote sites who need to adhere to guidelines provided by a company In accordance with an exemplary embodiment the memory 330 can be easily pro grammed for customized information through an associated Flash input USB port or other interface CONCLUSION Rotary switch memory mini measurement display and Info button glossary access can be integrated into a single multimeter Alternatively each can be provided separately or independently The user may be able to configure the multi meter to enable or disable rotary switch memory mini mea surement or the Info button Many specific details of certain embodiments of the inven tion are set forth in the description and in FIGS 1 11 to provide a thorough understanding of these embodiments A person skilled in the art however will understand that the invention may be practiced without several of these details or additional details can be added to the invention Well known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the invention Unless the context clearly requires otherwise throughout the description and the claims the words comprise com prising and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense that is to say in the sense of including but
31. osition of rotary switch 120 can correspond to a specific screen displaying pertinent information to the function in use As shown in FIG 1 some positions of rotary switch 120 may include more than one symbol in which case the symbol closest to rotary switch 120 is the default measuring function Where only one sym bol corresponds to a position that symbol denotes the default measuring function A menu item in rotary switch positions can provide one or more virtual buttons corresponding to soft keys 110 113 to allow the user to select between primary functions available within the rotary switch position as will be discussed below with reference to FIGS 4 and 5 Dedicated mode buttons provide direct single press access to measurement modes HOLD button 125 can be used to hold the currently displayed measurement value MIN MAX 126 button can be used to capture the highest lowest and average readings over time RANGE button 127 can be used to manually select a measurement range Other modes may be selected by using soft keys 110 113 and navigation buttons 115 117 to make selections from menus on display 105 In the example shown in FIG 1 rotary switch 120 can remain in its current position when multimeter 100 is turned off and back on using the separate ON OFF button 118 This method of turning multimeter 100 on and off allows multim eter 100 to be turned off and back on without losing track of the presently active measurement fu
32. t function selection received from the user inter face for a certain rotary switch position to associate the alternative measurement function selection with the rotary switch position in the place of the default mea surement function thereby modifying the measurement setting corresponding to the switch position and amemory for storing the modified measurement setting wherein when the rotary switch is rotated away from and back to a rotary switch position for which the measure ment setting has been modified and the processor 16 received from the user interface the enable command the processor is further configured to retrieve the modi fied measurement setting from the memory and associ ate the position of the rotary switch with the alternative measurement function in the place of the default mea surement function 8 The digital multimeter of claim 7 wherein the memory configured to store the modified measurement setting is non volatile 9 The digital multimeter of claim 7 wherein the user interface is further configured to receive a disable command and wherein when the rotary switch is rotated back to a position for which the measurement setting has been modi fied and the processor received the disable command the processor associates the position of the rotary switch to the default measurement function
33. t so long as rotary switch 120 does not change positions When RSM is on and functions and or modes are set in a first position of rotary switch 120 multimeter 100 will remember the functions and or modes for the first position As a result when rotary switch 120 is moved to a second posi tion and then returned to the first position the functions and or modes previously set in the first position will remain A non volatile memory can allow RSM settings to be remem bered if the batteries are taken out of multimeter 100 In some instances a user may only use a certain function and or mode for a position of rotary switch 120 and not use the default settings If the user sets the function and or mode once the settings will remain the same until RSM is turned off the user changes the secondary function and or mode or the user resets defaults The user can reset all positions to default functions with one command through a menu on display 105 Alternatively individual positions can be reset to default functions without affecting the settings for other positions Returning to the example shown in FIGS 1 7 if the RSM function is enabled and rotary switch 120 is toggled back to position 132 while in the screen shown in FIG 7 the multi meter will automatically return to the screen of FIG 3 Ifthe RSM function is disabled and rotary switch 120 is toggled back to position 132 while in the screen shown in FIG 7 the multimeter will automatica
34. tage 123 45 VAC 202 the maximum measurement value 304 the average measurement value 306 and the minimum mea surement value 308 Each of the maximum average and minimum measurement values include an optional time stamp 310 denoting at which time the measurement values were detected FIG 4 illustrates a screen in which mVDC a default func tion has been selected by toggling rotary switch 120 to posi tion 138 To change the measuring function from mVDC to temperature the user can press soft key 110 which corre sponds with Menu 412 FIG 5 illustrates an example of a function and mode menu that can appear after pressing soft key 110 in the screen shown in FIG 4 The user can select temperature by using navigation keys 114 117 to highlight a 20 25 30 35 40 45 50 55 60 65 6 box 504 located next to Temp as shown in FIG 5 When Temp is selected the functions corresponding to soft keys 110 113 can become F 506 C 508 and close 510 as shown in FIG 5 By selecting F 606 the multimeter can measure temperature in degrees Fahrenheit By selecting C 508 the multimeter can measure temperature in degrees Cel sius Selecting close 510 can close the menu and return the display to the screen shown in FIG 4 FIG 6 illustrates a screen that can be displayed after C 508 has been chosen in FIG 5 FIG 7 illustrates a screen that can appear after a us
35. tch 120 RSM can be permanently enabled for only certain positions of rotary switch 120 In these embodi ments the user can control whether RSM is enabled in the positions in which RSM is not permanently enabled FIG 8 illustrates a flow diagram for the procedure followed by the multimeter when the rotary switch is moved to a new position In step 801 the application processor detects whether rotary switch has moved In step 802 the application processor determines whether RSM has been enabled which can be done using the setup menu as referred to above If RSM is disabled in step 806 application processor will revert back to the default measurement function Then the applica tion processor continues to steps 808 and 809 in which the multimeter performs the measurement and displays the mea surement value Ifthe application processor detects that RSM has been enabled in step 803 the processor will retrieve data stored by the memory corresponding to the current switch position In step 804 the application processor will determine whether the function in the current switch position was pre viously changed to a function different from the default func tion If the measurement function has previously been changed to a function different from the default function in 20 40 45 50 55 60 65 8 step 805 the processor will select the measurement function previously used Then the application processor will proceed to step
36. ter 100 is illustrated in FIG 1 In the exemplary embodiment the multimeter can be housed with a compact handheld body including contour indentations so as to improve suitability for one handed operation The face of multimeter 100 is generally character ized by a display area 105 a rotary switch 120 soft keys 110 113 navigation buttons 114 117 dedicated buttons 125 128 and various input jacks 121 124 Multimeter 100 can be powered by four AA alkaline batteries not shown and as described below in greater detail Measurement Functions and Modes Multimeter 100 may be used to provide a primary mea surement function such as voltage current temperature resistance continuity conductance capacitance diode test low impedence low resistance 50 Ohms and AC DC com binations AC DC AC DC Primary measurement functions are mutually exclusive to one another such that no two primary functions can be measured simultaneously However secondary measurement functions associated with acircuit signal being measured such as frequency duty cycle pulse width decibels and crest factor can be provided at the same time as a primary function to convey additional mea surement information for user display Meter 100 in accordance with an exemplary embodiment may be set to display certain modes that operate in con junction with a measurement function These modes deter mine how measurements are acquired and r
37. tes a different measuring function For example a rotary switch on a conventional multimeter may be configured such that a first position corresponds to a voltage measurement a second position corresponds to a current measurement and a third position corresponds to a resistance measurement In this manner a single instrument can act as a voltmeter an amme ter or an ohmmeter by simply rotating a switch Since modern digital multimeters provide far more func tionality than just three measurement types rotary switch interfaces have been devised such that a single rotary switch position can be toggled between several measuring functions As examples a single position of a rotary switch may corre spond to different units of measurement such as Amps A or milliamps mA or even different measurement types altogether such as a current measurement or a temperature measurement Typically the multimeter provides capability on the switch itself or on a function key to toggle between the different measurement functions within the single rotary switch position Another feature found in modern digital multimeters enables a user to select between different modes that affect what or how measurements are acquired maintained or dis played For example a user can select a Minimum Maxi mum mode which updates the display with the highest and lowest detected measurement values As another example a user can select to Record
38. to the specific embodiments disclosed in the specifica tion unless the above Detailed Description section explicitly defines such terms Accordingly the actual scope of the invention encompasses not only the disclosed embodiments but also all equivalent ways of practicing or implementing the invention under the claims While certain aspects of the invention are presented below in certain claim forms the inventors contemplate the various aspects of the invention in any number of claim forms For example while only one aspect of the invention is recited as a means plus function claim under 35 U S C sec 112 other aspects may likewise be embodied as a means plus function claim Accordingly the inventors reserve the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the invention We claim 1 A digital multimeter comprising a rotary switch having a plurality of positions correspond ing to different default measurement functions to be performed a processor for modifying the default measurement func tion in at least one of the positions of the rotary switch to have a different measurement setting and a memory for storing the modified measurement setting wherein the processor is configured such that when the rotary switch is rotated away from and then back to a position for which the default measurement function has been modified the processor retrieves the modifi
39. ved Dynamically configure status bar Threshold value exceeded X es Include lightening bolt warning New mode selected FIG 10 U S Patent Dec 1 2009 Sheet 11 of 11 US 7 626 375 B2 a 1102 1106 03 13 06 9 08 10 pm 4 123 45 VAC Measure Volts DC O KJ Volts DC measures the direct current signals AA The lightning bolt indicates a measurement that exceeds the safe amount for contact with without protection 1108 1110 A Indicates a zeroing of the indac Next Prev More Exit 1112 4114 1116 1118 FIG 11 US 7 626 375 B2 1 SYSTEM AND METHOD FOR CONFIGURING A DISPLAY FOR A DIGITAL MULTIMETER BACKGROUND Multimeters are used for measuring a variety of parameters associated with electrical circuitry such as currents voltages resistance and capacitance A multimeter can be a handheld device useful for basic fault finding and field service work or a sophisticated bench instrument that can measure with a very high degree of accuracy The instrument may be implemented with an analog meter deflected by an electromagnet or with a digital display such as an LCD liquid crystal display screen While older analog multimeters might have basic accuracies of 5 10 modern portable digital multimeters or DMMs may have accuracies up to 0 025 Multimeters commonly include rotary switches configured such that each rotated position of the rotary switch indica
40. y when necessary the status bar may include a display of the live actual mea surement reading and an icon indicating whether such a reading might be considered dangerous and to be handled with caution To preserve space on the display screen the status bar may be positioned at the top of the screen as shown in FIG 1 or optionally at a side or bottom area of the screen In some embodiments the positioning of the status bar may be configurable by a user Importantly the overall font of the information displayed on the status bar can be significantly smaller than the font by which other information is displayed on the main area of the screen Accordingly in some embodiments a mini measurement can be displayed automatically when the primary function s measurement is not displayed or is otherwise obscured from view on the screen As yet another example as shown in FIG 9 a user may select a hold mode for freezing the display of a measurement such that the main area of display 105 does not report the live actual reading As shown in FIG 9 the status bar 902 includes an area 904 in which a mini mea surement informs the user of the live reading while display 105 is frozen with a past reading on hold As shown in FIG 9 the status bar displays the reading with the unit symbol or other indicia that would otherwise appear in the primary measurement Additionally when a secondary function is the primary measurement the min
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