RELAY FUNCTIONALITY:
RELAYS
(PRESENCE OR
PULSE)
VEHICLE
PRESENT
NO VEHICLE
LOOP FAULTY
NO POWER
N/O CLOSED OPEN CLOSED CLOSED
PRESENCE
RELAY N/C OPEN CLOSED OPEN OPEN
N/O PULSE CLOSED OPEN OPEN OPEN
PULSE RELAY N/C PULSE OPEN CLOSED CLOSED CLOSED
INSTALLATION GUIDE:
1. The detector should be installed in a waterproof housing as close to the loop as possible.
2. The loop and feeder should be made from insulated copper wire with a minimum cross-sectional area of
1.5mm2. The feeder should be twisted with at least 20 turns per metre. Joints in the wire are not
recommended and must be soldered and made waterproof. Faulty joints could lead to incorrect operation
of the detector. Feeders which may pick up electrical noise should use screened cable, with the screen
earthed at the detector.
3. The loop should be either square or rectangular in shape with a minimum distance of 1 metre between
opposite sides. Normally 3 turns of wire are used in the loop. Large loops with a circumference of greater
than 10 metres should use 2 turns while small loops with a circumference of less than 6 metres should use
4 turns. When two loops are used in close proximity to each other it is recommended that 3 turns are used
in one and 4 turns in the other to prevent cross-talk.
4. Cross-talk is a term used to describe the interference between two adjacent loops. To avoid incorrect
operation of the detector, the loops should be at least 2 metres apart and on different frequency settings.
5. For loop installation, slots should be cut in the road using a masonry cutting tool. A 45o cut should be
made across the corners to prevent damage to the wire on the corners. The slot should be about 4mm
wide and 30mm to 50mm deep. Remember to extend the slot from one of the corners to the road-side to
accommodate the feeder.
6. Best results are obtained when a single length of wire is used with no joints. This may be achieved by
running the wire from the detector to the loop, around the loop for 3 turns and then back to the detector.
The feeder portion of the wire is then twisted. Remember that twisting the feeder will shorten its length, so
ensure a long enough feeder wire is used.
7. After the loop and feeder wires have been placed in the slot, the slot is filled with an epoxy compound or
bitumen filler.
LD200 SERIES
VEHICLE LOOP DETECTOR
The LD200 is a dual channel inductive loop detector. The use of microprocessor and surface mount
technology enables a large number of functions to be incorporated into a small package. The LD200 is
compatible with most dual channel detectors on the market and is easy to set-up and install.
Typical applications in the parking and access control environments are safety loops, arming loops and entry
or exit loops as well as direction logic.
Standard features of the detector are :
• Reset Switch.
Pressing the reset switch enables the detector to be manually reset during commissioning and testing. This results in
the detector re-tuning the sensing loop and becoming ready for vehicle detection.
• Switch selectable Sensitivity.
The detect sensitivity is the minimum change in inductance required to produce a detect output. (%∆L/L)
Eight sensitivity settings are available on the switches to allow flexibility in configuration.
1 High - 0.01% 5 - 0.2%
2 - 0.02% 6 - 0.5%
3 - 0.05% 7 - 1%
4 - 0.1% 8 Low - 2%
• Switch selectable Frequency.
The frequency of the loop is determined by the inductance of the loop and the frequency switch setting. If the frequency
switch is on, the frequency is reduced. It may be necessary to change the frequency to prevent cross-talk between
adjacent loops.
• Selectable Extend Time.
When switched on this feature extends the outputs for 2 Seconds.
• Pulse Relay Selection.
The detect relay may be configured for a pulse output, and to energise on detection of a vehicle or when the vehicle
leaves the loop.
• Selectable N/O or N/C relay output.
Internal jumpers enable the output relay contacts to be configured for normally open or normally closed contacts.
• Direction Logic.
This feature enables the detector to give a pulse output on relay1 for a vehicle travelling from loop1 to loop2 and a
pulse
output on relay2 for a vehicle travelling from loop2 to loop1. To enable this feature switches 2 and 4 must be on.
• Selectable Pulse Time.
This feature sets the length of time that the pulse relay will be energised for. 1 Second or 0.2 Second.
• Power Indicator.
This LED Indicator illuminates when power is present.
• Detect Indicator.
This LED Indicator is illuminated when there is a vehicle over the loop or the loop is faulty. This LED can also be used
to determine the loop frequency. On reset, count the number of times the LED flashes. Multiply this number by
10KHz.For example: if the LED flashes 6 times, then the loop frequency is between 60KHz and 70KHz.
• Loop Fault Indicator.
This LED Indicator is illuminated when the loop is either open circuit or short circuit and is used to give a visual
indication of a faulty loop.
300mm 300mm
1M
ROAD
EDGE
45OCROSSCUT FEEDER
TRAFFIC DIRECTION
4m
