Page 10
Pro-120 controller instructions
11 Adjustments
Do not
use excessive force when adjusting the
presets: these are quite small and are easily damaged.
11.01
Gain
This is marked ‘Gain’ on the diagram ‘Features’. Set
this so that, at maximum required pot range, the
controller just reaches full speed: this is easiest to do
with the motor unloaded. Set the speed pot to your
required maximum point (e.g. full up) then, listening
to the motor, adjust the preset. It it usually quite easy
to tell when the motor stops accelerating. Too low a
setting and the motor will not reach full speed (this
can be useful to restrict top speed).
Too high a setting and there will be a ‘flat’ spot at
maximum speed where the control has no effect.
This will also confuse the special ‘power down’
circuitry so you will get a bumpy ride if you switch
off at speed.
Maximum setting of the gain preset will give full
output for about 3v input. The sensitivity can be
increased by fitting a resistor: contact the factory for
details.
11.02
Full speed
Where user adjustment of the top speed is required
the ’gain control’ is not satisfactory. In this case the
arrangement below can be used.
Both pots should be the same value (10K). The
resistor shown in the green lead to the top speed
adjust pot is optional: if left out (open-circuit) the top
speed will adjust between 50% and 100%
resistor
none 50% - 100%
10K 33% - 100%
4K7 25% - 100%
3K3 20% - 100%
2K2 15% - 100%
1K2 10% - 100%
linked: 0% - 100%
Alternatively, you can simply fit a resistor in the top
of the pot (red wire) but the value of this resistor plus
the pot should not exceed 20K.
11.03
Ramps
The Pro series controllers incorporate very
sophisticated ramps to control the acceleration and
deceleration rates. These are user adjustable and, to
get best performance from your machine, you should
adjust them!
Acceleration ramp
This is shown as ‘Accel’ on the ‘Features’ diagram.
It is present to make the vehicle accelerate smoothly
when the speed pot is increased suddenly so as to
avoid sudden surges and shocks to the mechanics. As
supplied it is at half setting so that the motor takes
about 3 seconds to accelerate.Adjust it as you require
to give smooth acceleration. Clockwise increases the
time (reduces the acceleration) anticlockwise
decreases the time (increases the acceleration) If the
time is set too short (anticlockwise) the vehicle’s
acceleration will be limited by the current limit
which does no harm (except that repeated accel/decel
will cause over heating) but it means that
acceleration is not being controlled properly, so will
vary depending on the gradient.
Deceleration ramp
This is shown as ‘Decel’ on the Features diagram: it
is present to make the vehicle decelerate smoothly
when the speed pot is reduced suddenly. As supplied
it is at half setting (about 3 seconds). Adjust it as you
require to give smooth deceleration. You will usually
find you require a lower setting (more anticlockwise)
for Decel than for Accel. If the Decel time is set too
low (anticlockwise) then the relays will drop out and
short out the motor before regenerative braking has
finished. This may give a jerk before the vehicle
stops completely and may also shorten the life of the
relays.
11.04
RAT and MST
Two other presets exist: we advise against altering
these.
Normal setting is centre scale.
Another sensible setting is with both fully
clockwise.
RAT. As the throttle is moved from zero, at a low
setting one or other direction relay engages
(depending on the selected direction). This is the
RAT (Relay Acceptance Threshold). At the same
Blue
Green
Top speed adjust
Speed control pot
Red
