WO1995018955A1

WO1995018955A1 - Improvements in a hydrostatic altimeter

Info

Publication number: WO1995018955A1
Application number: PCT/US1995/000218
Authority: WO
Original assignee: The Stanley Works
Priority date: 1994-01-05
Filing date: 1995-01-05
Publication date: 1995-07-13
Also published as: AU1599495A

Abstract

A hydrostatic measurement module (24) senses elevation relative to a fluid reservoir under atmospheric pressure. The measurement module further includes multiple functions and modes. One function allows the invention to measure heights and elevations beyond its physical extent. A hold function freezes the stable display values. A mark function sets upper/lower limit tones. A record function allows a larger number of measurements to be taken for real time average, minimum or maximum display (55) of data. A scale function can be used to select one of five display scales. A resolution function permits more rapid readings at lower precision. A temperature function displays ambient temperature. A record data function is used to accumulate or to download data. An inspect/dump function allows dump of stored recorded data or inspection of stored data as a function of sequence and position. An elevation function can be used to display any desired elevation.

Description

IMPROVEMENTS IN A HYDROSTATIC ALTIMETER

BACKGROUND OF THE INVENTION

This invention relates to hydrostatic altimeters such as disclosed in U.S. Patent No. 4,878,297 by Vories, and in particular to certain operational functions as described herein.

Advantages and attributes of this invention will be readily discernable upon a reading of the text hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a functional block diagram of a measurement module according to this invention.

Figures 2A-2E are elevational views of a measurement module and base unit according to this invention.

Figures 3A and 3B are views illustrating the use of HOLD and ZERO functions.

Figure 4 is a view of a display portion of this invention related to a SCALE function.

Figures 5A and 5B are views illustrating the use of a CAL function. Figures 6A and 6B are views illustrating the use of a REC function.

Figure 6C is a functional block diagram of a REC function.

Figures 7A-7C are views illustrating the use of a MARK function to select tone parameters.

Figures 8A and 8B are views illustrating the use of an ADDER function.

Figure 9 is a functional block diagram of an INSPECT/DUMP function. Figure 10 is a view illustrating the use of a CARRY function.

Figure 11 is a functional block diagram of the CARRY function.

Figures 12A and 12B are views illustrating the use of an ELEV function. Figure 12C is a functional block diagram of the ELEV function.

Figure 13A is a view illustrating the use of a REC DATA function. Figure 13B is a functional block diagram of the REC DATA function.

Figure 14 is a functional block diagram of a serial communication link between a measurement module according to this invention and a computer, such a lap top.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to Figure 1, a measurement module is illustrated to have a processing unit 2 which is preferably a microcontroller. The microcontroller includes program memory, preferably pre-programmed read- only memory (ROM) , and also communicates with a non¬ volatile read/write memory, preferably EEPROM 4. The microcontroller also controls a display, such as a liquid crystal display 6, and an audio device, such as a piezo buzzer 8. Preferably the microcontroller and associated circuitry are powered by a battery and power circuits 12. The microcontroller receives, as input, key stroke signals from a keypad 10 and digital data signals from an analog-to-digital convertor 14 which converts an analog signal received from a pressure transducer 18 via an amplifier and interface circuit 16. The signal from the transducer is a measure of the hydrostatic pressure sensed by the transducer in a liquid filled flexible tube communicating with a body of liquid, such as described in U.S. Patent No. 4,878,297 by Vories. The microcontroller also communicates with a serial communication port 5, such as an asynchronous communication port commonly found on personal computers and lap-top computers. The analog-to- digital converter also receives analog signals from internal and external temperature sensors 20 also via the amplifier and analog interface circuit.

Referring to Figures 2A-2E, a base unit 22 is connected to the measurement module 24 via a flexible fluid conduit 26. The base unit has an internal fluid reservoir contained in a chamber at least partially walled by a flexible bladder that is subject to atmospheric pressure ambient to the base unit. The fluid reservoir is in fluid pressure communication with a hydrostatic pressure transducer (not shown) in the measurement module via fluid in the flexible conduit 26. These elements combine and cooperate to produce the digitized hydrostatic signals 25 (Figure 1) as described in the Vories' patent, U.S. Patent 4,878,297. The base unit further includes a reel mechanism 28 for spooling the flexible conduit 26 as needed. Preferably there is about 100 feet of flexible conduit all of which can be spooled on the reel mechanism by operation of a reel turning handle 30. Preferably the fluid reservoir is disposed within the center of the reel within its axle. The reel and the fluid reservoir container are housed in a casing 32 having a handle grip. The casing includes a passageway 34 which provides a channel for passage of the flexible conduit to and from the reel mechanism. The passageway also includes a portion for docking the measurement module. In this way, the flexible conduit can be entirely spooled on the reel mechanism and the measurement module stored within the casing for convenient transport. The outside entrance to the docking area can be closed by a sliding panel door 36 which slides up and down in opposing grooves defined by the casing. On a bottom (an arbitrary reference designation) of the base unit, the casing 32 defines a "T" shaped slot which opens the passageway 34 to the bottom of the base unit. This slot provides for unencumbered spooling and unspooling of the flexible conduit.

Referring again to 2A-2C and 2E, the base unit can also include upper and lower storage chambers 38 and 40 which open to a front (another arbitrary reference) of the base unit. The lower storage chamber is closable by the sliding panel 36 and the upper storage chamber is closable by a sliding panel 42. On a right side of the base unit is a tubular pocket 44 for storing a telescoping unipod 46. The use of the unipod will be described later. On the same side there is preferably an "L" shaped pocket 48 for stowing one or more "L" shaped stakes 50. These stakes can be used to anchor the base unit to any selected spot on the ground by passing one or both stakes through holes 52 defined by the casing and driving the stakes into the ground.

Referring to Figures 1, 2D and 4, the preferable face of a measurement module 24 is detailed. The most frequently used functions, called "labeled functions," are individually printed on the eight keys 54 comprising the keypad 10. A number of more advanced or less frequently used functions, called "hidden functions," may be accessed by logical key combinations. All keys except the Hold and On/Off keys must be pressed for a continuous period of time, such as two seconds, in order to be valid key entries. This is to minimize accidental operation of a function. Distinctive audible and display indicators are provided for ease of use. For example, when a display reading is stable, i.e. valid to read, the operator will hear an audible indication of such, preferably two short beeps of a "read ready" tone from the piezo buzzer 8. When a reading is stable to store in the memory 4, the microcontroller preferably produces a single long tone. All most recent settings and stored measurements are retained indefinitely in the non-volatile memory, even with power off and without a battery installed. Without movement of the module or a key press for four minutes, the module powers down but only after two long warning beeps at three minutes.

Referring to Figures 2D, 3A and 3B, the HOLD key is pressed to freeze the current elevation on the alpha¬ numeric display, and the key is pressed again to release the display to be updated. When the ZERO key is pressed for two continuous seconds, the current elevation of the measurement module then becomes the zero reference elevation or benchmark elevation. The function of the

HOLD key to freeze the display is particularly useful in situations where an operator can reach the measurement module, but cannot read the display. Figure 3A illustrates the framing of a building. The base unit 22 is at the ground or floor level but the measurement module is atop a wall frame 58 to measure the height of the frame. In such a situation, the operator can press the HOLD key to freeze the display then pull the module down to read the frozen display. In Figure 3B, the use of both the zero function and the hold function are illustrated. To measure the depth of a hole 60, the operator need not go into the hole to read the display. The operator first makes the elevation at the rim of the hole, the benchmark elevation. This is done by placing the measurement module at the rim of the hole as shown in phantom and pressing the ZERO key for a continuous two seconds. The operator then presses the HOLD key and lowers the measurement module to the bottom of the hole. The hold function will not freeze the elevation display until the module stops moving. After the module has rested at the bottom of the hole, the hold function will then freeze the elevation display, and the operator can then pull the module back out of the hole and read the depth of the hole referenced to the rim of the hole.

Referring to Figures 2D and 4, the values displayed in the alpha-numeric display can be in a plurality of dimensions. To the right of the alpha-numeric display is a column of dimension indicators shown largest in Figure 4. Since the entire display is preferably a liquid crystal display, only one of the dimension indicators will be visible at a time. The quotation marks (") will be visible if the displayed values are in fractional inches. The "IN" indicator will be visible if the displayed value is in decimal inches. The "FT" indicator will be visible if the displayed values are in engineers' feet. The "F-I" indicator will be visible if the displayed values are in builder's feet-inches. The "CM" indicator will be visible if the displayed values are in centimeters. Figure 4 has an example of an elevation value (62.0 centimeters) in the various corresponding dimensions. A desired dimension is selected by continuously pressing the SCALE key and then releasing it at the appropriate time. After two seconds, the dimension indicators will become visible in a rotating sequence and when the desired one is visible, the SCALE key is then released. Alternately, the SCALE key can be pressed and released during rotation to manually sequence through the indicators. Referring to Figure 2D, the resolution of the values displayed in the alpha-numeric display can be selected from among preferably three: highest precision, intermediate precision and lowest precision for rough measurements. The higher the resolution, the longer it takes for the measurement module to indicate that a reading is stable. This is due to the fact that the hydraulic system requires more time to develop a high precision reading versus a reading of lower precision. To select a resolution, the RES key is pressed for two seconds and held to select a desired resolution. When the RES key is held for two seconds, the display begins to show the selectable resolutions in sequence. For example, it will display "RES.l" for highest precision, then it will display "RES.2" for intermediate precision, then it will display "RES.5" for the lowest precision, and then it will redisplay "RES.l", and so on. An operator merely releases the RES button at the desired resolution. An operator can also manually sequence through the resolutions by holding the RES button for two seconds and then pressing and releasing, and doing this repeatedly. Referring to Figures 2D, 5A and 5B, a calibrate function is illustrated. The calibrate function is used to calibrate the measurement module for accurate span measurement. The calibrate function runs by the micro- controller is used in conjunction with the unipod 46 of calibrated length to achieve calibration. An operator first affixes the measurement module to the top of the fully extended unipod, such as by conventional screw means. The operator then presses the CAL key for two seconds which starts a three beep tone. The operator then lays the module on a surface approximately level with the center of the horizontal base unit and again presses the CAL key. When [48] flashes on the alpha-numeric display, the operator then raises the unipod upright which raises the measurement module forty eight inches above the surface, and presses the CAL key again. The microcontroller then compares the value it is reading from the analog-to-digital converter to a value corresponding to 48" and uses any difference as a correction factor for future readings. Upon completion of the calibration function, the microcontroller causes the alpha-numeric display to read 48". To exit the calibration function prematurely, the CAL key is pressed for two seconds continuously.

Referring to Figures 2D and 6A-6C, the use of the invention to compute the average, minimum, and maximum values for an unlimited number of measurements is illustrated. The REC key is pressed for a continuous two seconds to initiate a record mode and activate the REC indicator on the display. Data previously saved in non¬ volatile memory may be viewed by momentary closures of the REC key to sequence through average, minimum and maximum displays. The HOLD key is momentarily pressed on entering the record mode to clear a maximum elevation register 64, an average elevation register 66 and minimum elevation register 68. The operator thereafter takes any number of elevation measurements over a desired area and the microcontroller calculates the maximum, average and minimum elevations and stores them in their corresponding registers. Average data is the sum of all measurements divided by the number of measurements taken. Every new measurement is compared with the contents of the minimum and maximum registers, if smaller the minimum or larger the maximum replaces the contents of the respective register. To view these values the operator presses the REC key to cause a selector 70 to sequence the contents of the registers to the alpha-numeric display or to memory 72. The display mode selected by the Record key will allow continuous display of either the real time elevation with the REC indicator, the average of all measurements with the REC average indicator, the minimum of all measurements with the REC minimum indicator or the maximum of all measurements with the REC maximum indicator. Figure 6A illustrates the use of the record mode to calculate the fill needed below concrete. The module is first zeroed at the bottom level for concrete within a form 62 and a number of measurements are made. The volume of fill needed is calculated by multiplying the average elevation value times the area to be covered by concrete. Figure 6B illustrates the record mode to predict the elevation of an uneven lot to be leveled by cut and fill. The operator picks a corner for a benchmark site and then takes a number of measurements across the lot. The operator then uses the REC key to sequence the display to the average value which is the lot elevation after it has been cut and filled.

Referring to Figures 2D and 7A-7C, a mark function is illustrated. The mark function is used by an operator to take advantage of the audible tone generating capability of the invention to give audible indications when the measurement module is at a selected elevation, within a selected band of elevations, or without a selected band of elevations. The mark function is initiated by placing the measurement module at a selected elevation, the mark level, and then pressing MARK key for two seconds. If the MARK key is again pressed at that same elevation, then the piezo buzzer 8 (Figure 1) will sound a tone whenever the memory module is at that elevation. If prior to pressing the MARK key a second time, the module is lowered to a second desired elevation, the second pressing of the MARK key will set up a tone band of elevations, i.e. a band within which a tone will be sounded. The width of the band will be equal to twice the difference between the mark level and the lower elevation with the mark level being the center of the band. If prior to pressing the MARK key a second time, the operator raises the module to a second selected elevation, then a no-tone band will be created with a band width twice the difference between the mark level and the second selected elevation with the mark level being the center of the band. Thereafter, whenever the module is at or above the high end of the band, the module will preferably emit a steady tone, and whenever the module is at or below the bottom of the band, the module will preferably emit a pulsing tone. A fraction bar within the alpha-numeric display flashes while in the Mark function. The MARK key is pressed for two seconds to exit, and settings will be lost. To exit and retain settings, the MARK and ON/OFF keys are pressed together.

The measurement module also has internal and external temperature sensors as previously discussed (item 20 of Figure 1) . An operator can cause the temperature to be displayed on the alpha-numeric display by pressing the

ON/OFF key for two seconds when first turning the module on. At that point the temperature will be displayed. Pressing any other key exits the temperature mode.

Referring to Figures 8A and 8B, an adder function is illustrated. In one mode the adder adds the height of the measurement module for measurements between its bottom and top. Figure 8A is an example of this. When the operator makes the upper measurement, the adder function is initiated by pressing the HOLD key to freeze the upper measurement and then pressing the MARK key for two continuous seconds. This causes the microcontroller to add the height "h" of the module to the frozen measurement dl to arrive at the true elevation H. The adder function also corrects for back down to back up measurements (e.g. floor to ceiling inverted) . Figure 8B is an example. Again, the operator freezes the upper measurement by pressing the HOLD key, but then the operator presses the REC key for two continuous seconds. This causes the microcontroller to add the width T of the memory module to the measured height d2 to derive the true elevation H. Referring to Figure 9, an inspect-dump function is illustrated. Data stored in the non-volatile record data registers can be visually inspected by an operator or communicated to a computer, such as a personal computer. To inspect, an operator presses the CAL and REC keys simultaneously for two seconds. This puts the micro¬ controller in an inspect mode and the contents of a first register are displayed. The operator can then sequence through the registers by preferably ones and tens, either up or down. Preferably pressing the CAL key sequences the records down by ten. Pressing the REC sequences the records down by one. Pressing the MARK key sequences the records up by one and pressing the HOLD key sequences up by 10. The contents of each selected register is transferred to a current record data elevation register, and from there it is accessed by the display which provides sequence, position and elevation information. Pressing REC and CAL keys momentarily causes the microcontroller to transfer the contents of the non¬ volatile registers to a computer via the serial port.

An initialize function allows the resetting of all operator settings (including calibrations) to default values and returns from any function to the normal display function. This is a way to recover from an unwanted function. This initialize function is actuated by pressing the CAL, REC, MARK and HOLD keys simultaneously for two seconds.

Referring to Figures 10 and 11, a carry function is illustrated. By using the carry function, this invention can be used to measure the height of a mountain or locate an elevation across town with no pencil, paper or calculator needed. The carry function allows measurements over any distance or elevation on Earth without manual tabulation or computation by simply leap froging the measurement module with the base unit. To start, the ZERO and MARK keys are pressed together for two seconds at the reference or benchmark which causes the display to alternate CARRY and [0] until E_rt is stable. This writes - E_rt = E₀ into the zero register and clears the carry register for a zero reading at the benchmark for both the normal and the carry display modes. The measurement module is moved to the limit of cord range in the direction of the final destination and the HOLD key is pressed locking the present elevation E_rt + E₀ on the display and into the carry summing register. Without moving the measurement module, the base unit is moved as far as the cord will allow in the direction of the destination and when secured in position the ZERO key is pressed two seconds causing the carry/normal selector to select the carry function and sum E_z (-E_rt for the new base unit position) with the carry register contents for an output to the display of E_C=E₀+E_z+E_rt. In the carry function the display alternates between a upper display having a leading "C" and a lower display, the two displays are required to accommodate more range than a single display. This hold/carry sequence can be repeated indefinitely over any distance or elevation. Within any set-up, one may exit the carry function by pressing the ZERO key for two seconds causing the carry/normal selector to switch to the normal display where En=Eo+Ert if in the first set-up where carry was zeroed or En=Ez+Ert in a subsequent set up where Ez represents the elevation of the last carry hold/zero. As the functional diagram illustrates, the measurement module can then be zeroed anywhere within the set up outside of the carry function and later re-enter the carry functions anywhere within that set-up and continue toward the destination without corruption of carry register data. When the elevation set function is used at the benchmark, Eo becomes the preset elevation.

Referring to Figures 12A and 12B, illustrates an elevation function. By this function an operator can preset the resident module display 55 to a bench mark elevation in engineers' (FT) scale for use in the carry function. To enter the elevation function, an operator presses the SCALE and RES keys simultaneously for two continuous seconds. Once the elevation function is initiated, the key pad becomes basically a numeric key pad for setting the bench mark elevation. Pressing RES key sets the thousandth digit and the SCALE key sets the hundredths digit. The CAL key sets the tens, the REC key sets the ones, the MARK key sets the tenths, the HOLD key sets the hundredths digit and the ZERO key selects whether the sequence of digit entry is up or down. These values are set in a carry elevation register which can be viewed by the display. The elevation and carry functions are cleared to zero by pressing the MARK key and the ZERO key for two seconds. For very high elevations, the alpha¬ numeric display alternates between most significant and less significant digits as illustrated in Figure 12B. Bypassing this through-hole is another pair of broadly coupled signal tracks 92A and 92B.

Referring to Figures 13A and 13B, the record data function allows storage of measurements for later recall or transfer to a personal computer for tabulation and analysis or graphing of site profiles, sections, three dimensional or contour maps. To enter or exit the record data function, the REC and MARK keys are pressed for two seconds. Previous contents of the non-volatile sequence and position counter registers are cleared by pressing the REC and Zero keys together for two seconds. Each momentary press of the HOLD key increments the position counter and stores the new position value with the elevation in non-volatile data registers. During this process the same information is sent out the serial port and the position and sequence are momentarily flashed on the display. Pressing the MARK key for two seconds increments the sequence counter. Twenty measurements before the registers are filled, the display flashes FULL and the number of measurement registers remaining. When all registers are filled, positions are preceded with an "F{" rather than a "P" with each measurement taken and the data continues to be sent to the serial port for real time recording on a portable or pocket PC of any number of measurements. Figure 13A illustrates the use of this function for taking measurements over a grid of regular surface intervals for a contour or three dimensional map. One sequence can define a profile (PI, etc.) or section (SI, etc. ) .

Referring again to Figure 2, the CAL indicator flashes if the module should be recalibrated due to a temperature change. It is on constantly when the module is outside of the -22F to +122F operating temperature range because measurements may be in error. A --0-- periodic flash on the display indicates re-zeroing is needed due to temperature change. The figure "8888" alternates with displayed elevation when the module is more than 20' above or below the base unit. Over-range measurements may be in error. The indicator BAT flashes when a few hours of battery life remain. A fresh 9V Alkaline battery can allow up to 100 hours of use.

Referring to Figure 14, another highly unique and significant improvement is the serial port which can be wireless, e.g. infrared coupled. The port permits simplex dumping of either stored or real time data to an RS-232C port of an office or field PC for analysis, tabulation or plotting of profiles, 3D or Topographical maps. The serial port is also used for automated factory test of the product. This factory test mode is entered by pressing both the ON/OFF and CAL keys for one or two seconds while switching on the power. Since the auto power down is disabled in this mode the measurement module might be used for continuous monitoring of elevation for data logging to a modem or portable PC at a remote site such as water storage tank, stream or reservoir. A "Read Ready" tone sounds a pair of short beeps when the most recent incoming data samples are stable to within a preset tolerance (such as +/-0.1") of the averaged reading on the display.

A "Store Ready" tone sounds a single long tone only when the most recent incoming data to be saved is within a preset tolerance (such as +/-0.050") of the averaged display data.

The foregoing description and drawings were given for illustrative purposes only, it being understood that the invention is not limited to the embodiments disclosed, but is intended to embrace any and all alternatives, equivalents, modifications and rearrangements of elements falling within the scope of the invention as defined by the following claims. I CLAIM:

Claims

1. In an hydrostatic altimeter, a method for measuring elevations beyond the span of the altimeter's link, the steps comprising: (a) pressing MARK and ZERO to clear carry register, (b) pressing HOLD to freeze the current elevation, (c) holding the measurement module in place while the base unit is moved to a new location further along the path to being measured,

(d) actuating the CARRY function, (e) repeating steps b - d over the entire distance to be measured, and (f) keying an exit to the CARRY function.

2. In an hydrostatic altimeter having a measurement module with a display, an improvement comprising means for performing a hold function.

3. The improvement of claim 2 further comprising means for performing a zero function.

4. The improvement of claim 2 further comprising means for performing a mark function.

5. The improvement of claim 2 further comprising means for selecting a measurement resolution from a plurality of resolutions.

6. The improvement of claim 3 further comprising means for selecting a measurement resolution from a plurality of resolutions.

7. The improvement of claim 2 further comprising means for calibrating the measurement module.

8. The improvement of claim 3 further comprising means for calibrating the measurement module.

9. The improvement of claim 2 further comprising means for calculating the average elevation from a plurality of elevation measurements.

10. The improvement of claim 3 further comprising means for calculating the average elevation from a plurality of elevation measurements.

11. The improvement of claim 2 further comprising means for providing a audible indication whenever the measurement module is at an elevation within a predetermined set of elevations.

12. The improvement of claim 2 further comprising means for providing a audible indication whenever the measurement module is at an elevation without a predetermined set of elevations.

13. The improvement of claim 2 further comprising means for compensating in elevation measurements for predetermined orientations of the measurement module.

14. The improvement of claim 2 further comprising means for performing a carry function.

15. The improvement of claim 2 further comprising means for performing a record function.