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Program description: Mixers
General notes regarding freely programmable mixers
The two menus »Wing mixers« and »Helicopter mi-
xer«, described on the preceding pages, contain a
wide range of ready-programmed coupling functions.
The basic meaning of mixers has already been ex-
plained on page 84, together with the principle on
which they work. In the following section you will fi nd
more general information relating to “free mixers”:
The mc-22s offers freely programmable mixers in
every model memory, whose inputs and outputs can
be selected to suit your exact requirements:
• four linear mixers, numbered 1 to 4;
• two curve mixers, numbered 5 and 6.
These six mixers are certainly adequate in most ca-
ses, but in any case are invariably suffi cient when you
incorporate the facilities of fl ight phase programming.
In the »MIX active/phase« menu (see page 108) you
can specify which of the six mixers is active or disab-
led in each fl ight phase separately.
Any control function (1 to 12) can be assigned as the
input signal of a “free mixer”. Alternatively any exter-
nal switch can be assigned as the input signal using
what is termed the “switch channel” (see below). The
signal present at the control channel, and passed to
the mixer input, is always affected by the associa-
ted transmitter control and the set transmitter control
characteristics, as defi ned, for example, in the »Dual
Rate / Expo«, »Channel 1 curve« and »Control ad-
just« menus.
The mixer output acts upon a freely selectable control
channel (1 to max. 12 – depending on receiver type).
Before the signal is passed to the associated ser-
vo the only infl uences which can act upon it are tho-
se defi ned in the »Servo adjustment« menu, i.e. the
servo reverse, neutral point offset, servo travel and
servo travel limit functions.
One control function can be set up to affect sever-
al mixer inputs simultaneously, if, for example, sever-
al mixers are to be arranged to work in parallel. Con-
versely it is possible for several mixer outputs to affect
one and the same control channel.
For more complex applications several mixers can
even be connected in series: in this case the input of
the “series-connected” mixer is not the (transmitter
control) signal at the “output” of a control function, but
the signal (mixed or otherwise) present “further back”,
i.e. at the “input” of a control channel. The following
description of the free mixers includes examples of
such arrangements.
In software terms the freely programmable mixer is
always switched on by default once set up, but it is
possible to assign an optional ON / OFF switch to any
mixer. However, since there are so many functions
to which switches can potentially be assigned, you
should take care not to assign too many functions to
any particular switch.
The two vital mixer parameters are …
… the mixer ratio, which defi nes the extent to which
the input signal acts on the output of the mixer.
If you are using linear mixers, the mixer ratio
can be set symmetrically for both sides of cen-
tre, or asymmetrically; the two curve mixers 5 and
6 can be confi gured by defi ning a maximum of
fi ve points at the user’s discretion, providing the
means to implement extremely non-linear curves.
… the neutral point of a mixer, which is also termed
the “offset”.
The offset is that point on the travel of a transmit-
ter control (stick, rotary knob or switch module) at
which the mixer just has no infl uence on the cont-
rol channel which is defi ned as its output. Normal-
ly this is the centre point of the transmitter cont-
rol, but the offset can be placed at any point on
the control’s travel. Since there are no restrictions
on the design of the curve mixers, setting a mixer
neutral point only makes sense with the four linear
mixers.
If you do not wish the corresponding mixer output or
control channel to be affected by its normal transmit-
ter control, then it can be separated from the control
channel of the mixer output by a simple button-press
in the »MIX-only channel« menu (see page 108).
This might be the case, for example, if you wish to
use output 1 for another purpose in the case of a gli-
der not fi tted with airbrakes. The following menu de-
scription will make this function clear with a practical
example.
Switch channel “S” as mixer input
In many cases a constant control signal is all that
is required as the mixer input; a typical applicati-
on would be to apply slight up-elevator trim when the
aero-tow coupling is closed.
If you assign the same switch to the aero-tow re-
lease and the mixer, the coupling can be opened and
closed by operating the switch, and at the same time
the appropriate up-elevator trim is applied automati-
cally. To identify this special arrangement, this mixer
input control function in the program is designated “S”
for “Switch channel”.
Note:
In the default state of the mc-22s transmitter the
»Free mixers« menu is initially suppressed. To acti-
vate it, move to the »Suppress codes« menu (see
page 49). Alternatively, move to the »Basic settings«
menu (see page 117) and select “yes” for the Expert
mode; this must be carried out before you set up a
new model memory..
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