Page 11
VTX series instructions
The adjustment presets are identified in the diagram
on page 4.
Gain
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.
Maximum setting of the gain preset will give full
output for about 3v input.
Ramps
The VTX series controllers incorporate linear ramps
to control the maximum acceleration and deceleration
rates. These are user adjustable and, to get best
performance from your machine, you should adjust
them to best suit your application.
Acceleration ramp
This is labelled as ‘ACC’ on the 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 mechanical components.
As supplied it is normally at half setting so that the
motor takes about 2 seconds to accelerate. Adjust it
as you require to give smooth acceleration.
Clockwise increases acceleration (reduces time to full
speed), anticlockwise decreases acceleration
(increases time to full speed). If the acceleration is set
too high (anticlockwise) the acceleration may be
limited by the current limit, which does no harm but
means that acceleration is not being controlled
properly, so will be dependent on motor load.
Deceleration ramp
This is shown as ‘DEC’ on the diagram: it is present
to make the vehicle decelerate smoothly when the
speed pot is reduced suddenly. As supplied it is
normally 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 DEC than for ACC. 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, giving a jerk
before the vehicle stops completely. This will also
shorten the life of the relays.
Warning
Be careful not to set the ramps too fast: if reversing is
too fast the relays can arc, causing them to stick and
also shortening their life. This is fully explained on
our www site:
http://www.4qd.co.uk/serv/nccramp.html
11: Adjustments
10: Boxed Controller
Battery–
Motor+
Motor–
198mm
88mm
Fuse
6 core
control cable
green
blue
red
white yellow
black
locating notch
View on soldered pins
of Bulgin 6 pin
(option)
line mounting female
