User manual PowerBox Competition SR2

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• Auto matching
The Auto matching function is a completely new development, and this is the rst
PowerBox product to include it. Its purpose is to match the travels of up to three
mechanically interconnected servos accurately over ve points, which it accom-
plishes in just a few seconds.
How does auto matching work?
The Competition SR2 is tted with the latest generation of micro-controller which
is capable of measuring the current drawn from both batteries extremely quickly
and precisely. The values for measured current are used to match two or three
mechanically linked servos to each other.
This is accomplished by moving each servo to ve points in turn and recording
the lowest current values. The process is carried out in two steps: initially coar-
sely, then nely. A third stage then follows, in which ne-matching is carried out,
taking into account any stiffness in the control surface hinges.
In the initial stage the servos are strained hard against each other for very brief
periods (5 x 100ms). We have carried out hundreds of tests with this procedure,
and have found that it presents no problems to servos - even low-cost examples.
In fact any linkage and servo must be capable of withstanding this procedure in
any case, otherwise they would not be able to cope with ight loads.
Which servo types are suitable for auto matching?
All types of servo are suitable - with one exception: servos which do not become
“soft” when the signal is switched off. There are a few digital servos which remain
xed at their position even when no signal is present. In steps 1 and 2 of auto
matching this would cause the servos to draw a high current for an extended
period, i.e. for as long as the matching process lasts, and this is not acceptable.
Such servos can only be matched manually!
Start
In the rst servo-matching display you select your main servo under Output. In
most cases this would be - in the case of ailerons - the servo closest to the fuse-
lage. Connect the servo, and set the centre and travel at the transmitter. Initialise
the servo with maximum travels.