after a presence detection and holds the increased sensitivity until
the detection drops out, at which time sensor sensitivity returns to
the original setting.
n. Power requirement: 120V/60Hz, or be provided with appropriate power
module/assembly and appurtenance, which is suitable for operation with
120V/60Hz.
o. Loop Wire.
(1) Provide number of inductive loops as per manufacturer's
recommendations based on loop size and distance between loop and
loop amplifier.
(2) Ensure that the loop slots in which the loop wire is laid are free
from debris, sharp objects, and are completely dry. Clean out
slots with compressed air before installing loop wire.
(3) Install loop wire in layers. Install backer rods over top wire at
a minimum of
300 mm
1 foot
spacing to ensure uniform placement of
wire in the slot. Fill the loop slots with sealant per
recommendation of the loop wire manufacturer.
(4) Use 16AWG stranded cable with Cross Linked Polyethylene insulation
installed in a PVC sleeve. Loop wire extending from the loop to
the loop amplifier shall be twisted with a minimum twist pitch of
18 per m
6 per foot
.
(5) Check conductor resistance to ground with "megger" of 500V or
higher. Remove and replace the whole installation if ground
resistance of less than 10 mega-Ohms is measured.
(6) Provide TVSS (Transient Voltage Surge Suppressor) for both
loop-wire terminations at or near the loop detector module.
Ground the TVSS with minimum 10AWG insulated ground wire of high
strand-count to the closest ground termination point.
(7) Loops shall be capable of detecting motorcycles, passenger
vehicles, and high bed trucks with the same sensitivity setting.
2.11.3 Radar
**************************************************************************
NOTE: Select either Point or Continuous over speed
detection as required
**************************************************************************
Radar detection sensors may be used for vehicle over speed detection.[
Point Over speed Detection. The detector unit shall be capable of
detecting the speed of one or more vehicles at a point in the ACP Approach
Zone and closing an alarm contact if the vehicle speed is over a preset
value.][ Continuous Over speed Detection. The detector unit shall be
capable of continuously detecting the speed of vehicles within preset zones
as they approach the ID Check Area of the ACP. The Sensor shall close an
alarm contact when the speed of any vehicle anywhere within the zone is
above a preset value. See drawings for required detection zones and
detector speed settings. For radar sensors which sense speed at multiple
discrete points in the direction of travel instead of continuously, the
distance between discrete points shall not be more than
5 m
15 feet
.]
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