PREVOST H3-45 - Wheelchair Lift System - Threshold Warning System (Tws) Adjustment; Adjust Aiming of Acoustic Sensor Beam; Test Aim of Acoustic Sensor Beam

Other Features 5-51
PA-1628Operator's ManualH3-45 COACH
WHEELCHAIR LIFT SYSTEM -
THRESHOLD WARNING SYSTEM
(TWS) ADJUSTMENT
There are three verifications to perform;
1. Adjust Aiming of Acoustic Sensor Beam,
2. Test Aim of Acoustic Sensor Beam, and
3. Adjust Acoustic Sensor Timing.
Adjustment of the sensor timing is done at the
factory and should not need to be repeated in the
field. Readjustment should only be considered if the
sensor aiming could not be adjusted to ignore both
the wheelchair in the aisle and the platform during its
normal movement.
ADJUST AIMING OF ACOUSTIC SENSOR
BEAM
1. Place wheelchair with passenger in center
aisle of coach, pointed at doorway where
Threshold Warning System (TWS) is
installed. The TWS should not detect a
wheelchair and passenger when they are
located this far from doorway.
TWS AREA
2. Place wheelchair with passenger in center
aisle of coach, pointed at doorway where
Threshold Warning System (TWS) is
installed. The TWS should not detect a
wheelchair and passenger when they are
located this far from doorway.
3. Place wheelchair with passenger in center
aisle of coach, pointed at doorway where
Threshold Warning System (TWS) is
installed. The TWS should not detect a
wheelchair and passenger when they are
located this far from doorway.
NOTE
Only in rare instances will adjustment be needed in
the counterclockwise direction
TWS MODULE DETAIL
TEST AIM OF ACOUSTIC SENSOR BEAM
1. Move wheelchair and passenger slowly
towards doorway. TWS should detect
wheelchair and passenger (LED will flash,
buzzer will sound and the module red light will
flash) when centerline of front wheels is
between 18 and 24 inches from doorway.
2. Open vehicle access door above lift. Lower
platform to ground and place wheelchair and
passenger at rear of platform. Rollstop (rear
barrier) should be up. Raise platform to floor
level. This normal platform motion with
wheelchair and passenger aboard should not
actuate TWS. If LED does flash (buzzer will
also sound and module red light will flash),
turn sensor adjustment screw slightly
counterclockwise.
NOTE
If an adjustment is made, repeat the previous step
where wheelchair is between 18 and 24 inches
from doorway.