Vestil EPT-30 - Manual (Page 64)

64
Curtis PMC 1207/1207A Manual A-9
APPENDIX A: GLOSSARY
In Figure A-3, the creep speed is kept at 10% and the maximum speed setting
dropped to 60%.
In all cases, the ramp shape number is the PWM output at half throttle, as a
percentage of its full range. So, for example, in Figure A-3, a 50% ramp shape
gives 35% PWM output at half throttle (halfway between 10% and 60%). A 30%
ramp shape gives 25% PWM at half throttle (30% of the range {which is 50%,
from 10% to 60%}, starting at 10% output, or {[.30 x 50%] + 10%} = 25%).
Ramp start
The ramp start feature allows the vehicle to be started with a higher plug current
limit to prevent rolling downhill. Ramp start increases the plug current limit for
the selected direction only. When the opposite direction is selected, ramp start
will be canceled and a 3-step sequence must be followed to re-activate it:
STEP 1. select a direction for more than 1 second,
STEP
2. return to neutral, and
STEP
3. re-select the same direction.
Once the vehicle is operating in ramp start mode, it will continue to do so until
the opposite direction is selected for more than one second.
When the brake is first released, the ramp start current limit level will be
obtained when either direction is selected in plug braking mode. In ramp start
mode, either direction selected will allow the ramp start current limit level. This
condition remains until the other direction is selected for more than one second.
The new direction then becomes the decision direction, and the 3-step ramp start
sequence is required to regain the ramp start current limit level in plug.
Fig. A-3 Ramp shape
(throttle map) for control-
ler with maximum speed
set at 60% and creep speed
set at 10%.
THROTTLE (percent)
PW
M (percent)
70%
60%
50%
40%
30%
20%
RAMP SHAPE
100
90
80
70
60
50
40
30
20
10
0
100 90 80 70 60 50 40 30 20 10 0
CREEP SPEED
(10%)
MAXIMUM SPEED
(60%)