MicroTim XB User manual

MicroTim XB™
Precision Digital Barometric Altimeter / Barometer / VSI
User Manual
Document Revision 1.0
Firmware Version 3.0

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Table of Contents
Table of Contents ..................................................................2
1 General Operation..........................................................5
1.1 Altitude Display Modes.........................................5
1.2 Units ......................................................................5
1.3 Restoring Factory Default Settings........................5
2 Display Mode Examples................................................6
2.1 ASL Display Example ...........................................6
2.2 AGL Display Example ..........................................6
3 Keypad Function Details ...............................................7
4 Setting the Barometric Pressure ....................................8
5 Field-Elevation Mode....................................................8
6 Barometer Mode ............................................................9
6.1 Activating Barometer Mode ..................................9
6.2 Calibrating the Barometer .....................................9
6.2.1 Calibrating Barometer Mode by Known Elevation 9
6.2.2 Calibrating by Known Barometric Pressure..9
6.3 Using the Barometer..............................................9
6.3.1 Barometer Units...........................................10
6.4 Exiting Barometer Mode .....................................10
7 VSI Mode ....................................................................10
7.1 Activating VSI Mode ..........................................10
7.2 Using VSI ............................................................10
7.2.1 VSI Units .....................................................11
7.2.2 VSI Deadband .............................................11
7.3 Exiting VSI Mode................................................11
8 Vertical Accumulator Mode ........................................11
8.1 Activating Accumulator Mode ............................11
8.2 Using the Vertical Accumulator ..........................11
8.2.1 Zeroing the Accumulator.............................12
8.2.2 Accumulator Units.......................................12
8.2.3 Accumulator Deadband ...............................12
8.2.4 Accumulator Sampling Rate........................12
8.3 Exiting Accumulator Mode .................................12
9 MicroTim XB Messages..............................................13
10 Changing the Battery...............................................13
Appendix A – Frequently Asked Questions........................14

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WARNING!
- DO NOT OVER-TIGHTEN THE SCREWS when changing the battery. Warranty does not
cover stripped screw holes.
- The battery cover is recessed to clear the battery and only fits correctly one way.
Observe the recessed battery cover when replacing the battery.
Serial Number_____________________
Firmware Revision Number__________
Checked: _________________________

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MicroTim XB is a precise, durable, low-power digital barometric altimeter.
Here are some of the major features of the MicroTim XB altimeter:
•Lightweight and portable.
•Ultra Low power consumption. Runs for many months on a single replaceable AAA penlight
battery.
•Battery monitoring. Typically several days warning of a low battery.
•Displays in units of meters/kPa or feet/inHg or feet/mbar.
•Barometric pressure adjustable.
•Factory calibrated.
•Durable. Moisture and vibration resistant.
•Can function as a high precision barometer.
•Can function as a VSI (Vertical Speed Indicator)
•Can function as a Vertical Accumulator (total vertical distance traversed).

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1 General Operation
MicroTim XB is turned on by holding the key until ‘boot’ appears on the display and release the key. All of
the configuration instructions in this manual assume MicroTim XB is already turned on and running.
The sealevel altitude (ASL) is displayed when no key activity has occurred in the past 5 seconds.
The barometric pressure setting corrects these altitude readings for weather changes and is set by single
press/releases of the altitude keys . The default barometer setting is 2992 (29.92 inHg).
1.1 Altitude Display Modes
MicroTim XB can be configured to display:
•ASL (default). Unsigned number. Arrow indicates negative readings (below sealevel).
•AGL (Altitude above Ground Level). Sign (+/-) is displayed to show altitude above (+) or below (-) the
location MicroTim XB was last zeroed at.
•Both AGL/ASL alternately every 2 seconds.
To change the display mode, hold the display key for 5 seconds then release. MicroTim XB will then flash the
selected display mode (ASL, AGL, BOTH) for 5 seconds.
1.2 Units
MicroTim XB displays altitude in feet and barometric pressure in inches of mercury by default. Three sets of units
are available:
1) Altitude in feet, barometric pressure in inches of mercury (default).
2) Altitude in meters, barometric pressure in kPa.
3) Altitude in feet, barometric pressure in millibars.
To change units, hold the units key for 5 seconds then release. MicroTim XB will then flash the selected unit
pairing (FEET, METR, FTMB) for 5 seconds.
After 20 minutes of inactivity (no key activity or significant altitude changes) MicroTim XB powers down. To
restore normal operation, press and hold the key until ‘boot’ appears on the display.
1.3 Restoring Factory Default Settings
By default, MicroTim XB is in altimeter mode, displaying ASL in feet and barometric pressure in inches of
mercury.

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Holding down the reset key for 5 seconds then releasing will restore these factory default settings.
During a system reset, MicroTim XB will display:
1) The unique electronic serial number, ‘sern’ followed by the serial number.
2) The firmware version, ‘frn’ followed by the firmware version.
3) A screen test, cycling from ‘0000’ to ‘9999’.
4) The defaulted barometric pressure, 2992.
then MicroTim XB resumes normal operation with the default settings.
2 Display Mode Examples
2.1 ASL Display Example
This is the altitude above mean sea level, also referred to as MSL.
The ASL altitude appears as an UNSIGNED number. In the case of being BELOW sea level, an ARROW will
appear in the upper left corner of the display to indicate an altitude below sealevel.
Examples of ASL readings:
ASL
Reading
Meaning
2368 MicroTim XB is 2368 units ABOVE
mean sea level.
←
0421
MicroTim XB is 421 units BELOW
mean sea level.
2.2 AGL Display Example
This is the altitude above a user-selected ground level.
The AGL altitude always appears with a ‘+’ or ‘-‘ sign. This is what distinguishes AGL from the ASL altitude
(ASL altitude uses an arrow to indicate values below sealevel). Zero the AGL at any altitude with a quick
press/release of the zero key .

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Examples of AGL readings:
AGL
Reading
Meaning
+1368 MicroTim XB is 1368 units ABOVE
ground level.
-0652 MicroTim XB is 652 units BELOW
ground level.
3 Keypad Function Details
There are three keys on MicroTim XB, not six.
Each key has 2 functions:
1. A primary function (upper text) activated by quick press/release.
2. A secondary function (lower text) activated by holding the key down for 5 seconds then releasing.

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4 Setting the Barometric Pressure
MicroTim XB contains a barometric pressure setting which allows the user to enter the current local barometric
pressure to correct the altitude readings for weather changes.
To VIEW the current barometer setting, press either of the alt keys once. MicroTim XB will display the
barometer setting for 5 seconds.
To CHANGE the barometer setting, repeatedly press/release the alt keys until the desired barometer
setting is achieved.
When viewing altitude in ‘metr’ (meters/kPa) mode, the barometric pressure reads in units of kPa and 101.32 kPa
will display as 10132.
When viewing in ‘ftmb’ mode, the barometric pressure reads in units of mbar (millibars). Note that since the
decimal point is not shown, mbar units will display the same as kPa units. For example, 1013.2 mbar will read as
‘10132’.
When viewing in ‘feet’ mode, the barometric pressure displays in units of inHg, and 29.92 inHg will display as
2992.
5 Field-Elevation Mode
Many users will not have access to the current barometric pressure for their area, but will know their current
starting elevation. Trial and error finding the correct barometric pressure setting to produce this known starting
elevation can be tedious. To ignore barometric pressure altogether, and dial in a known starting elevation, place
MicroTim XB in field-elevation mode.
To toggle MicroTim XB between field-elevation (fld) and barometric pressure (bp) modes, do a quick press/release
each of the keys in the following sequence:
That is: up/down/up/down/zero, up/down/up/down/zero.
Then ‘fld’ or ‘bp’ will appear on the screen, verifying that the mode has been successfully changed. Repeat this
sequence until desired mode appears.
Note: To prevent accidental activation of the bp/fld mode selection, MicroTim XB ignores the sequence if more
than 2 seconds elapses between any of the keypresses in the sequence.
Once field-elevation mode is achieved, pressing the alt keys now immediately displays the newly adjusted
altitude. In this mode MicroTim XB does not display the barometric pressure at all but still adjusts the altitude by
0.01 inHg (0.339 mbar or about 9.3 feet) with each or keypress.
Note: Upon reset, MicroTim XB defaults to ‘bp’ mode.

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6 Barometer Mode
MicroTim XB is primarily for altitude indication. However, it can also be configured to act as a high-precision
barometer when it remains at a constant elevation. Barometer mode is activated by executing a special system
reset.
6.1 Activating Barometer Mode
To activate barometer mode:
1) Begin a system reset by holding down the key for 5 seconds then releasing the key. The system reset
will begin when the key is released. During the reset MicroTim XB will show the serial number ‘sern’ and
firmware revision number ‘frn’ followed by a screen test starting with ‘0000’ and ending with ‘9999’.
2) At any time during the screen test (before ‘9999’ appears) press and hold the key. If this key is being
HELD DOWN as the reset cycle completes (i.e. showing 9999 on the screen) then MicroTim XB will enter
barometer mode. Do not release the key until ‘baro’ appears on the display. MicroTim XB is now in
barometer-mode and you may release the key.
6.2 Calibrating the Barometer
When set to barometer mode, MicroTim XB assumes a barometric pressure of 29.92 inches of mercury. This
reading needs to be calibrated to your elevation. Once it has been calibrated, the barometer will read correctly
always, unless MicroTim XB is moved to another elevation.
6.2.1 Calibrating Barometer Mode by Known Elevation
If you know the elevation MicroTim XB is at, you can calibrate the barometer by entering this elevation. Press the
keys until the correct elevation appears on the screen. The elevation will increment in 9.3 foot steps,
equivalent to 0.01 inHg at sealevel. Select the elevation closest to your true elevation. After no keys have been
pressed for 5 seconds, MicroTim XB will stop displaying the reference elevation and show the correct barometric
pressure.
6.2.2 Calibrating by Known Barometric Pressure
Note that alternatively you may simply know the current barometric pressure in your area and use the
keys to force MicroTim XB to this value. From then on, MicroTim XB will display the correct barometric pressure.
6.3 Using the Barometer
In barometer mode, MicroTim XB displays the barometric pressure constantly. MicroTim XB updates the reading
once per minute. After an idle period of approximately 30 minutes, MicroTim XB will power down. The barometer
will resume operation any time afterward by turning the unit back on (holding the key until ‘boot’ appears on
the display).

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6.3.1 Barometer Units
The three unit combinations available in altimeter mode are also available in barometer mode. The default is inches
of mercury for pressure and feet for reference elevation (inHg/feet). You may toggle through metric (kPa/meters)
and mixed (mbar/feet) by holding the key for 5 seconds then releasing.
6.4 Exiting Barometer Mode
Normal altimeter operation is restored by executing a NORMAL system reset (by initiating a reset and NOT
touching any keys until it is complete). See section 1.3, Restoring Factory Default Settings.
7 VSI Mode
MicroTim XB is primarily for altitude indication. However, it can also be configured to act as a VSI (Vertical
Speed Indicator). Like barometer-mode, vsi-mode is activated by executing a special system reset.
7.1 Activating VSI Mode
To activate VSI mode:
3) Begin a system reset by holding down the key for 5 seconds then releasing the key. The system reset
will begin when the key is released. During the reset MicroTim XB will show the serial number ‘sern’ and
firmware revision number ‘frn’ followed by a screen test starting with ‘0000’ and ending with ‘9999’.
4) At any time during the screen test (before ‘9999’ appears) press and hold the key. If this key is being
HELD DOWN as the reset cycle completes (i.e. showing 9999 on the screen) then MicroTim XB will enter
vsi-mode. Do not release the key until ‘VSI’ appears on the display. MicroTim XB is now in vsi-mode and
you may release the key.
7.2 Using VSI
In vsi-mode, MicroTim XB displays your vertical speed in units per minute (feet per minute by default). A ‘+’ sign
indicates climb, and a '-' sign indicates sink.
Some examples of VSI readings are:
VSI
Reading
Meaning
+ 0160 MicroTim XB is CLIMBING at an
average rate of 160 units per minute.