LX Zeus v 3.4.3
10.9.2014
- 39 -
2.2.2.3
TE level and TE filter
TE level***,
set TE compensation style, 0% for tube compensation
TE filter***,
only valid by electronic TE compensation
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 setting is the fastest while the 5 setting
provides maximum damping.
The second filter, called the Smart Vario, is a dynamic filter and controls the rate at which the vario indication
moves. When set to OFF, there is no restriction on the rate of movement of the vario indication other than
the setting of the time constant filter. When set to 1, the vario indication will not move faster than 1 m/s (2
kts) per second, while when set to 4, the vario indication will not move faster than 4 m/s (8kts) per second.
It should be noted that when set to 4, the vario indication will move four times faster than when set to 1.
Summary:
The Smart Vario should not be used in isolation but in conjunction with the setting of the time constant filter.
When the Smart Vario is activated, the time constant filter may need further adjustment to provide optimum
indications.
***
LX Zeus has the capability to offer variometer total energy compensation in two ways. Selection of
compensation method is done after selection of the % figure. 000% means total energy compensation by
using a TE
tube. When using this solution the unit does not process compensation, this depends entirely
on the TE tube and its installation. After an input of a percentage that is other than zero the special software
routines will be activated and will provide an electronic compensation process. The default value is 100%
but this can be varied following a test flight.
The TE compensation can be fine-tuned during flight with the following procedure. It is essential that this
is only done in smooth air; it is not possible to tune the TE accurately when there is a lot of thermal activity.
Select 100 % and default
TEF (TE filter)
Accelerate up to approximately 160 km/h (75 kts) and keep the speed stable for a few seconds
Gently reduce the speed to 80 km/h (45 kts)
Observe the vario indicator during the manoeuvre. At 160 km/h (75 Knots) the vario will indicate about
–2
m/s (-4kts). During the speed reduction the vario should move towards zero and should never exceed zero
(slightly positive indications are acceptable). If the vario shows a climb, then the compensation is too low,
increase the TE%; and vice versa. Repeat this procedure and make further adjustments if necessary.
The
TEF
(TE filter) is the compensation delay. Larger numbers will increase the delay and vice versa. During
the first test is recommended to use TEF 4.
Electronic TE is only effective when the pitot and static sources are co-located and the pneumatic lines to
the instrument are approximately the same length. The best sensor to use is the combined pitot/static
Prandtl tube. If problems are experienced with the electronic TE compensation, then the most likely cause
is the glider's static source. The static source can be checked by changing the connection of the pneumatic
tubes for electronic compensation, and then setting the
TE:
to 0%. In still air, accelerate to approximately
160 km/h (75 Knots) and reduce the speed. Observe the vario indicator. If the static source is good, then
the vario should immediately start to move showing a climb. If the needle initially shows increased sink and
then moves to a climb, the static source of the glider is unsuitable and there is no way to provide successful
FILTER
0.5 to 5
SmartVario
FILTER
1 to 4 or OFF
RAW VARIO
FILTERED
VARIO
VARIO
INDICATION
Note!
Electronic and pneumatic TE compensation requires
different connection of tubes.