Page 8
Pro-120 controller instructions
9.01
Speed pot
We advise a 10K linear pot, although you can use
any value from 4K7 to 20K.
The gain adjustment on the
controller alters the amount of
rotation required before full speed
is reached: this allows various
input devices to be used.
The simplest speed control is an
ordinary rotary pot: this won’t give
any ‘dead man’ control as the pot
won’t return to zero when it is
released. 4QD can supply a spring
return to zero hand control or a
plunger operated pot (linear
position sensor), suitable for
incorporating into a foot pedal.
9.02
¶ Use as voltage follower
Instead of a pot, the input may be fed from a variable
voltage. 0v (common) to pin F, signal input (+ve) to
pin E. A resistor (10k) should be connected from pin
D to pin F to over-ride the internal pot fault detector
circuit. Zero speed will be for zero voltage input and
full speed voltage may be adjusted (by the pre-set) to
be from 3v to above 20v.
The reverse line may also be operated by a voltage.
With zero volts present controller will operate in
forward. Apply a voltage (any voltage over
approximately 5) and reverse will be selected.
9.03
Ignition (On/Off) switch
Circuitry in the controller switches it off (zero
current consumption) unless pins A and B of the
connector are joined. Therefore a switch must be
fitted.
There are three ways of factory wiring the
ignition:the following notes apply to the standard
controller, not to the RW version.
Do not permanently link these pins. For correct
operation, the ignition switch must be turned on (or
the hand control box plugged in) after power has
been applied to the controller. If the ignition switch
is turned on before power is applied then the ignition
relay may not pull in properly as its operation relies
on the Pro’s internal capacitor charging through a
bleed resistor before the ignition switch is closed.
Beware of opening the switch when the motor is
running: the motor will brake to a halt more or less
quickly, depending on the deceleration ramp setting.
With the ignition off, or even
with the battery disconnected,
the relays short out the motor
so free-wheeling is not
possible. To freewheel
properly the motor should be
disconnected.
The Pro controller has special
circuitry so that, if the ignition
is switched off at full speed,
the motor will be braked to a
stop (under control of the
deceleration ramp) and only
when it has stopped will the
ignition relay switch off. For
this to work properly it is important that the ‘Gain’
control is not turned up too far - see section 11.01.
9.04
¶ High Pot lock-out
This feature switches off the ignition if this is
activated with the speed pot other than at low speed
to guard against the vehicle taking off because the
ignition is activated with the throttle depressed.
In some applications this feature may be undesirable.
e.g. with a Joystick Interface when the system will
not power up unless the stick is central at switch on -
this can cause confusion!. It can be disengaged by
simply removing the header marked HPLO on the
diagram ‘features’ - page 4.
Note
: the Trickle Resistor (p.4) may get hot when
HPLO is engaged and a relay may click on and off.
9.05
¶ UVP (Battery Discharge Protection)
this can be used to protect the the battery from
damage that could be done by over-discharging it.
To do this, the voltage at the controllers battery
terminals is monitored and the performance is
reduced as this voltage falls.
The level is factory set to a low voltage (about 15v)
so the feature is effectively inactive on 24v
controllers. For 12v controllers the feature must be
totally deactivated by fitting the header marked UVP
in the features diagram (page 4).
To enable UVP on 24v, fit the 12K resistor R
uvp
Speed
Min
Max
On
Off
Reverse
Forward
F
E
D
C
B
A
