LX9000 Version 2.6
September 2011
Page 94 of 130
6
Variometer and Altimeter
All signals from the pneumatic sensors (altitude, speed) are derived from high quality
pressure sensors which mean that no flask is necessary. The vario signal is derived from the
altitude signal. All signals are temperature and altitude compensated. Mechanical needle
and colour display are displaying the vario information as well as many other parameters.
The display is user configurable. The variometer can be configured to show:
•
Range
5, 10 and 2.5 m/s or 10, 20 and 5 kts.
•
time constants
0.1 s to 5 s, in addition there are 4 settings for electronic processing
for the vario signal.
•
netto
shows the air mass lift and sink.
•
relative
shows the lift or sink that would be achieved if the glider was circling at the
thermaling speed.
There are two ways by which the vario indications can be corrected for total energy;
electronic TE compensation based on speed changes with time and pneumatic compensation
with a TE probe. The quality of the TE compensation depends entirely on the location, size
and dimension of the TE tube. The installation must be leak-proof.
If an electronic TE compensation is selected the TE (P
st
) port should be connected
to a good static pressure source. If pneumatic compensation is selected the TE
(P
st
) port should be connected to the TE probe.
6.1
Smart Vario Description
The LX system incorporates two configurable electronic filters in the circuitry. The first filter
adjusts the time constant and is adjustable between 0.5 and 5 seconds. The 0.5 second
setting is the fastest while the 5 second setting provides maximum damping.
The second filter, called the Smart Vario, is a dynamic filter and controls the rate at which
the vario indicator moves. It behaviour differs depend on variometer type.
6.1.1
Smart vario on V5 vario system
On V5 variometer smart vario filter defines how much filter is different for increasing vertical
speed versus decreasing vertical speed. (E.g.: If vario filter is set to 1s and Smart vario filter
is set to 4, then filter for increasing vario be 1s and for decreasing vario it will be 2s). This
will produce an effect like on Sage variometer.
6.1.2
Smart vario on other vario systems
On older models of variometer smart filter value gives us four levels of dynamic damping of
the vario. When set to
OFF
there is no restriction on the rate of movement of the vario
indicator other than the setting of the time constant filter. When set to 1 the vario indicator
will not move faster than 1 m/s (2 kts) per second, whilst when set to 4 the vario indicator
TE (Pst)
LX9000
Electronic TE compenstaion
Compensation with TEprobe
