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2.
Sampling Frequency
Acc. FAI rules, the measurement must be performed at least 10 times per second. Altimeter
ALT-USB has the ability to set the measurement frequency. It is best to set
15 measurements per second. This ensures fast measurement with accuracy. Setting
a higher frequency of measurements reduces the measurement resolution (to 1 meter)
3.
Setting "manual reset"
Altimeter can be reset in two ways: by using software or by altimeter’s contact closure.
During the event, set the lock of manual reset (parameter “manual reset "set to" No ").
A competitor himself can not reset the altimeter.
4.
Calibration of temperature.
During the conversion of the amount of pressure to height the air temperature is taken into
account. Altimeter has a built-in temperature sensor. In altimeter’s settings this sensor can
be calibrated. Before the calibration altimeter be should put in place ensuring the ambient
temperature for about 5 minutes (not connected to power). Then connect to your computer
and enter the current temperature settings (field Setup -> “Calibration of the Temp.”).
5.
Number of competitors
In the "Competitor No." enter the number.
Before measuring, you must reset the altimeter. This can be done through the program,
pressing the button "Reset". After an additional confirmation, the message of altimeter reset
appears. You can now disconnect it from the computer and connect the battery. Proper reset is
signaled by a single, short-blinking LED. No reset is signaled by 3 blinks of the diode. Altimeter
can also be reset by shorting the pins. To make this possible, you must first set the "Manual Reset"
to 'Yes'. If it is set to 'No', then reset is only possible through the program. Locking this reset is
required during the competitions
6. Assembly of altimeter in the model
It is very important how to install the altimeter in the model. In particular, this applies to
measurements on competitions. The chamber, in which the altimeter is assembled, can not be tight.
There must be holes, allowing the pressure around the altimeter to equalize atmospheric pressure.
Where should we locate the altimetr?
If you plan to put altimetru the rocket to be taken into account that the altimeter is a device
which measures changes in pressure. Therefore, should not be placed in the immediate vicinity
altimetru engine. Altimeter must be separated from direct gas engine. Ignition, which ejects the
tape brake can significantly distort the measurement results as well as destroy the same altimeter
(gases are very corrosive.) Therefore, you should always use the separating pistons. Must be
maintained order: engine, brake piston with tape or other separator, container from the altimeter.
Ventilation holes
For rockets S1 do not have ventilation holes (if the rocket is not hermetic)
For rockets S1 to be done two or three holes with a diameter of 0,3 mm – 0,4mm – (if the rocket is
hermetic)
For rockets S5 to be done two or three holes with a diameter of 0,4 mm – 0,5mm
In models of gliders, airplanes, just altimeter is placed inside the hull model. In models that do not
have a closed hull, perform a separate container where you put altimeter.
Summary of Contents for ALT-USB
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