Nortech PD27 Series User manual

HEAD OFFICE FACTORY
VCCE Office Park 32a Wiganthorpe Rd
170 Peter Brown Dr Willowton
Pietermaritzburg Pietermaritzburg
3201 South Africa 3201 South Africa
Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone]
PO Box 4099
www.nortech.co.za
Willowton Hub
[email protected]
3200 South Africa Nortech International (Pty) Ltd.
Reg. No. 1998/010951/07
PD27x
Dual Channel Parking Detector
User Manual
NORTECH INTERNATIONAL (PTY) LTD
All rights reserved
Copyright © 2016
Document Number: 307UM0200_01
Date of Issue: May 2016
This document is for informaon only and unless otherwise indicated, is not to form part of any contract. In
accordance with the manufacturer’s policy of connually updating and improving design, specifications
contained herein are subject to alteraon without noce.

307UM0200_01 May 2016 PD27x User Manual Page 2 of 30
Contents
1. Introducon ................................................................................................................................................................ 4
2. Technical Data ............................................................................................................................................................ 5
2.1 Funconal data.................................................................................................................................................. 5
2.2 Electrical Data ................................................................................................................................................... 6
2.3 Environmental Data .......................................................................................................................................... 6
2.4 Mechanical Data................................................................................................................................................ 6
2.5 Approvals .......................................................................................................................................................... 7
3. Operang Procedure .................................................................................................................................................. 8
3.1 Hardware setup................................................................................................................................................. 8
3.2 DIP Switch Selecons ........................................................................................................................................ 8
3.3 Front Panel Indicators ..................................................................................................................................... 10
4. Operaon.................................................................................................................................................................. 11
4.1 Detector Tuning............................................................................................................................................... 11
4.2 Detector sensivity ......................................................................................................................................... 11
4.3 Types of Outputs ............................................................................................................................................. 12
4.4 Response mes ............................................................................................................................................... 12
4.5 Powerfail ......................................................................................................................................................... 12
4.6 Automac Frequency Selecon ...................................................................................................................... 13
5. Installaon guide ...................................................................................................................................................... 14
5.1 Product Safety Requirements ......................................................................................................................... 14
5.2 Operaonal Constraints .................................................................................................................................. 14
5.3 Loop and Feeder Material Specicaon ......................................................................................................... 15
5.4 Sensing Loop Geometry .................................................................................................................................. 16
5.5 Loop Installaon.............................................................................................................................................. 16
6. Conguraon ............................................................................................................................................................ 18
6.1 PD271 Enhanced Detector - Order number 307FT0203 ................................................................................. 18
6.2 PD272 Enhanced Detector - Order number 307FT0201 ................................................................................. 18
6.3 PD274 Enhanced Detector - Order number 307FT0202 ................................................................................. 19
6.4 PD271 Enhanced Detector DIN Rail - Order number 307FT0206.................................................................... 19
6.5 PD272 Enhanced Detector DIN Rail - Order number 307FT0207.................................................................... 20
6.6 PD274 Enhanced Detector DIN Rail - Order number 307FT0208.................................................................... 20
7. Applicaons .............................................................................................................................................................. 21
8. Customer Fault Analysis............................................................................................................................................ 22
8.1 Fault Finding.................................................................................................................................................... 22
8.2 Funconal test................................................................................................................................................. 22
APPENDIX A - FCC ADVISORY STATEMENT ....................................................................................................................... 24
APPENDIX B – INSTALLATION OUTDOORS........................................................................................................................ 25
APPENDIX C – REQUEST FOR TECHNICAL SUPPORT FORM .............................................................................................. 26

307UM0200_01 May 2016 PD27x User Manual Page 3 of 30
WARNING: 1. This unit must be grounded (earthed) !
WARNING: 2. Disconnect power before working on this unit !
WARNING: 3. Installaon and operation by service personnel only !
WARNING: 4. No user serviceable parts inside. No internal settings. Warranty
void if cover removed !
WARNING: 5. Always suspend trac through the barrier area during
installaon and testing that may result in unexpected operation
of the barrier.
WARNING: 6. USA
FCC Advisory Statement – Refer to Appendix A at the end of this
document.
WARNING: 7. Europe
Disposing of the product:
This electronic product is subject to the
EU Direcve 2002/96/EC for Waste
Electrical and Electronic Equipment
(WEEE). As such, this product must not
be disposed of at a local municipal
waste collecon point. Please refer to
local regulations for direcons on how
to dispose of this product in an
environmental friendly manner.

307UM0200_01 May 2016 PD27x User Manual Page 4 of 30
1. Introduction
The PD27x Series Dual Channel Inducve Loop Vehicle Detector is a dual channel microprocessor based detector
designed specically for parking and vehicle access control applicaons. It is suited primarily for complex mullane
access control and counng applicaons. Using the most up-to-date technology, the PD27x has been designed to meet
the requirements of a vast number of parking applicaons pertaining to operang conditions and various opons
available to the user.
The primary funcon of the detector is to detect vehicle presence by means of an inductance change caused by the
vehicle passing over a wire loop buried under the road surface.
Figure 1. The PD27x Vehicle Detector (11 Pin housing on leand DIN Rail on right)
The detector has been designed for ease of installaon and convenience, with automac frequency selection to assist
with installaon, it is easily congured to suit various applicaons.
By making use of the DIP switches and push buon, the PD27x can be easily set up for the users applicaon needs. The
unit also provides diagnoscs by means of the Nortech DU100 and DU700 units.
The PD27x provides visual outputs (LED’s) on the front of the enclosure to provide an indicaon of the state of the
channels as well as the detector itself. The channel LED’s indicate whether a vehicle is present over the loop or there is
a fault on the loop while the power LED indicates that the unit has been powered, is operaonal and provides a means
of communicaon via the DU100 and DU700 units.
The unit has relay change-over contacts at the rear of the enclosure for providing outputs as congured by the front
panel DIP switches.
Although it is a dual channel detector, the design eliminates the possibility of crosstalk between the loops connected to
the detector by using sequential channel scanning.
Related Documents are listed below
Data Sheet Document No. 307DS0002
Installaon Leaet Document No. 307LF0002
2/4 Channel Vehicle Detector Installation Guide Document No. 879LF0006

307UM0200_01 May 2016 PD27x User Manual Page 5 of 30
2. Technical Data
2.1 Functional data
Tuning Fully Automac with opon to enable Automac Frequency Selecon (AFS)
Self-tuning range 20 µH to 1500 µH
Sensivity Four steps adjustable on the DIP switches (High, Medium-High, Medium-Low, Low)
Opons available are 0.01% ΔL/L, 0.02% ΔL/L, 0.05% ΔL/L and 0.10% ΔL/L
ASB (Automatic Sensivity Boost) is selectable via the DIP switches
Frequency With AFS switched on the channel tunes automatically to one of five possible frequencies
There are four selectable frequency opons with AFS switched o
Operang frequency of 18 – 110 kHz (Determined by loop geometry and frequency seng)
Output Configuraon 2 output relays
User congurable for: Presence on detect
Pulse on detect
Pulse Output Duraon 150ms
Presence Method Permanent or Limited presence
Presence Time Innite when the unit is on Permanent Presence
Dependant on level of detect and environmental condions when on Limited Presence
DriCompensaon Rate Approx. 1 %∆L/L per minute
Response Times Detect: 53.0 – 73.0ms
Undetect: 280.0 – 350.0ms
Subject to sensivity level, level of detect and speed of vehicle over the loop
Visual Indications 1 x Power / Status LED – Red
2 x Channel Status LED – Green
Reset Holding the reset buon for 3s iniates a retune
Surge protecon Loop isolaon transformer, gas discharge tubes, and Zener diode clamping on loop input.
Power Fail Innite memory retenon of detector state on power failure (provided certain criteria are
met refer to secon 4.5). This funcon can be turned on and o via the Reset push buon.

307UM0200_01 May 2016 PD27x User Manual Page 6 of 30
2.2 Electrical Data
Power requirements 120V AC ± 10% (48 to 62Hz) (PD271)
230V AC ± 10% (48 to 62Hz) (PD272)
Requirement: 1.5 VA Maximum @ 230V
12-24V ± 10% DC/AC (48 to 62Hz) (PD274)
Requirement: 1 VA Maximum @ 12 V
Relay Contact Rating Relay contact rang: 2A@30VDC, 0.5A@125VAC, 0.25A@250VAC
For ambient temperatures above 60°C De-rate the relay
Maximum current as per graph below:
2.3 Environmental Data
Storage Temperature -40°C to +80°C
Operang Temperature -40°C to +80°
Humidity Up to 95% relative humidity without condensaon
Circuit protecon Conformal coang over the PCB and all components
IP Rang IP30 – This product MUST be installed in an enclosure
2.4 Mechanical Data
Housing Material ABS blend
Mounng Posion DIN rail mounng and Shelf
Connecons 11-pin Submagnal (JEDEC No. B11-88) OR
2x 6 way Plugs on DIN Rail Mount

307UM0200_01 May 2016 PD27x User Manual Page 7 of 30
The gure below shows the 11 pin connector on the rear of the PDx7x unit, as well as the DIN Rail clip for the DIN Rail
housing version. The 11 pin connector plugs into a relay base that accommodates all of the wiring for the unit. A list of
acceptable relay bases is given below. The DIN Rail housing plugs directly onto the DIN Rail and is ed with 2x 6 way
connectors for wiring the necessary connecons.
Figure 2. PDx7x rear view showing the 11 pin connector on the leand the DIN Rail housing on the right
Relay base recommendaons:
Size of Housing 78mm ( High ) X 41mm ( Wide ) X 80mm ( Deep )
2.5 Approvals
CE Regulations: EN 301 489-3 Equipment Type: III Class of Equipment: 2
CISPR22
EN 50293 Performance Criteria B
Safety: IEC / EN 60950-1
Manufacturer Part Number
Finder 90.23
Bremas Ersce ES 12
TE connecvity (Schrack) MT78740
Schneider Electric RUZC3M
Ormron PF113A-D
Allen Bradley 700-HN101

307UM0200_01 May 2016 PD27x User Manual Page 8 of 30
3. Operating Procedure
3.1 Hardware setup
The PD27x Series dual channel parking detector is designed to be DIN rail mounted, with the controls and visual
indicators at the front, and wiring at the rear of the enclosure. The power, loop and relay outputs are connected to the
11 pin relay base at back of the housing.
3.2 DIP Switch Selections
3.2.1 Presence (switch 10)
The presence seng determines how the detector tracks a detect. There are two
modes, permanent presence and limited presence.
Permanent presence mode is aimed at maintaining the presence of a vehicle over
the loop by connuously compensating for all environmental changes. This is used
in situaons where safety is involved and the detector is required to maintain the
detect unl the vehicle leaves the loop.
Limited presence is aimed at liming the presence of a vehicle over the loop. This
is used in situaons where stascs or control is involved and a vehicle parked over
the loop should not prevent connued operaon. The presence time is related to
the size of the detect. Typically a 1% ∆L/L will timeout aer approximately 1 hour.
3.2.2 Pulse on detect / Presence on detect (switch 9 and 8)
When a vehicle enters the loop the relay can either give a 150ms pulse on detect,
or give an output for the entire me that the vehicle is detected by the detector.
This seng can be made for each channel respectively as indicated on the
faceplate.
3.2.3 Fail-safe or Fail-secure (switch 7 and 6)
The relay output polarity of the presence relay can be switched between fail-safe
and fail-secure via the DIP switches.
In fail-safe, the output is the same in detect as it is with no power applied to the
unit. Related to an access control situaon, this is used in situaons where the loss of power must not lock people out.
Either a valid detect situation, or a power failure/ fault will provide a signal.
In fail-secure, the output is the same in un-detect as it is with no power applied to the unit. Related to an access control
situaon, this is used in situations where the loss of power must not allow free entry. Only a valid detect situaon will
provide a signal.
3.2.4 AB Logic (switch 5)
AB logic can be used to count the cars going in a specified direcon. A transion from loop 1 to loop 2 (classified as
forwards) results in a 150ms pulse output on Relay 1. A transion from loop 2 to loop 1 (classied as backwards) results
in a 150ms pulse output on Relay 2. This funcon can easily be switched off by making use of the DIP switches as
indicated on the tables.
3.2.5 Automatic Sensitivity Boost (ASB) (switch 4)
ASB is a mode which alters the un-detect level of the detector, and can be toggled on or o via the DIP switches. ASB
causes the sensivity level to be boosted to a maximum on detecon of a vehicle, irrespecve of current sensivity level
and maintained at this level during the enre presence of the vehicle over the loop. When the vehicle leaves the loop
and the detecon is lost, the sensitivity level reverts to the pre-selected level. This is typically used for vehicles with high
beds, or vehicles towing trailers, where it is important to not lose the detect over the entire length of the vehicle.
3.2.6 Automatic Frequency Selection (AFS) (switch 3)
This seng allows the detector to briey evaluate all ve frequency bands and select the best operang frequency
available. The tuning time with AFS switched on can range between 5 to 20 seconds. With AFS switched off, the
frequency can be selected manually.
Figure 3. PD27x Faceplate

307UM0200_01 May 2016 PD27x User Manual Page 9 of 30
3.2.7 Frequency (switch 2 and 1)
The frequency switches are used to shift the operang frequency of the detector. This is primarily used to handle
situaons in which more than one detector is used at the same site. The detectors must be set-up to ensure no crosstalk
(interference) occurs between adjacent loops connected to different detectors. This is achieved by ensuring that the
loops of the two detectors are spaced sufficiently apart (approximately 2 metres between adjacent edges) and also
ensuring that the detectors are set to different frequencies.
The loops connected to multichannel detectors are not suscepble to crosstalk due to the design of the loop interface.
Sw2 Sw1 Frequency
Right Right High Frequency
LeRight Medium High Frequency
Right LeMedium Low Frequency
LeLeLow Frequency
3.2.8 Sensitivity (switches 1 to 4)
The sensivity of the detector determines the change of inductance necessary to produce a detect. The PD27x provides
a selectable range of four sensivity sengs. Sensitivity is defined as a change in the inductance, with the PD27x it
ranges from 0.01% to 0.1%, with 0.01% being the highest sensivity selecon.
Sw4 Sw3 Sensivity Channel 1
Right Right (0.01%) - High Sensitivity
LeRight (0.02%) - Medium High Sensitivity
Right Le(0.05%) - Medium Low Sensitivity
LeLe(0.10%) - Low Sensivity
Sw2 Sw1 Sensivity Channel 2
Right Right (0.01%) - High Sensitivity
LeRight (0.02%) - Medium High Sensitivity
Right Le(0.05%) - Medium Low Sensitivity
LeLe(0.10%) - Low Sensivity
3.2.9 Push button (Retune and Powerfail)
The push button can be used to iniate a retune or to switch Powerfail on or o depending on how long the push buon
is held in.
Switch Descripon Hold Funcon
Push
button
Reset 3 sec This would iniate a detector retune
Power fail
status 10 sec
Hold for 10s to determine the state of Powerfail. If the LEDs
are ON, Powerfail is ON. If the LEDs are OFF, Powerfail is
OFF.
Power fail
toggle 30 sec
Holding for 30s will toggle the Powerfail status. The state of
Powerfail is known after holding for 10s. Aer 30s, if the
LEDs turn OFF, Powerfail is now OFF. If aer 30s the LEDs
turn ON, Powerfail is now ON.
The PD27x has a Powerfail funcon which is designed to retain the memory of a vehicle on the loop in the event of a
power fail situaon. This is designed specically for fail safe situaons to retain the output state and prevent a glitch
on the outputs in the event of a power failure.

307UM0200_01 May 2016 PD27x User Manual Page 10 of 30
3.3 Front Panel Indicators
The front panel indicators consist of a Red Power / Communicaon LED and one Green Channel LED.
There are four possible conditions which are indicated by the LED’s.
•Idle condion – no vehicle is detected
•Detect condion – a vehicle is detected passing over the inducve loop
•Tuning condion – the detector is currently tuning to the loop
•Fault condion – the detector is unable to tune to the loop as it is either out of operaonal condions such
as low signal strength or frequency out of range, or there exists a fault on the loop such as a short circuit
or an open circuit.
If a loop fault exists, the Green Channel LED will come on and ash at a rate of 2Hz indicang that the unit is trying to
tune. If the fault is self-healing, the detector will connue to operate but the LED will flash at a slower rate of 1Hz
indicang to the user that a fault has occurred. The detector must be power cycled or reset via the pushbuon in order
to clear the historical fault informaon.
In the event of a vehicle passing over the inducve loop and causing a detect, the Green Channel LED will light up
indicang the presence of a vehicle and remain on for the duraon of the detect.
It should be noted that the Channel LED does NOT necessarily represent the output state of the relays. It only represents
the detecon of a vehicle over the loop. The relay state could, for example, be different from the LED state in the case
of a pulse output aer its pulse duraon or a fault output. The only me the Channel LED will go off while a vehicle is
sll present is if the channel is in limited presence mode and has expired.
The Red Power LED indicates that the unit is powered and funconal. The red LED is also used as a communicaon
interface with the DU100 / DU700 to obtain diagnoscs.

307UM0200_01 May 2016 PD27x User Manual Page 11 of 30
4. Operation
The inducve loop vehicle detector senses the presence of a vehicle over an area dened by a loop of two or more turns
of wire, laid under the road or pavement surface. This loop of wire is connected to the detector by a twisted pair of
wires called a loop feeder.
A vehicle passing over a sensing loop causes a small reducon in the inductance of the loop, which is sensed by the
detector. The sensitivity of the detector is adjustable to accommodate a wide range of vehicle types, as well as different
loop and feeder combinaons.
Upon detecon of a vehicle passing over the loop the detector operates its output relays, which may be used to indicate
controls associated with the installaon.
Figure 4. Magnetic field from inductive loop interacng with a vehicle
4.1 Detector Tuning
Tuning of the detector is fully automac. The detector will re-tune if any of the following events occur:
-When power is applied to the detector and Powerfail is OFF
-A channel reset is iniated via the push buon
-A detect of greater than 16% ∆L/L occurs.
-A fault has occurred and is self-healing.
The detector will automatically tune the channel to its connected loop. The detector will tune to any loop with an
inductance in the range 20 to 1500 micro-henries (μH).
This wide range ensures that all loop sizes and feeder combinaons will be accommodated in the tuning range of the
detector.
Once tuned, any slow environmental change in loop inductance is fed to a compensang circuit within the detector,
which keeps the detector correctly tuned.
4.2 Detector sensitivity
Sensitivity of the detecon system is dependent on factors such as loop size, number of turns in the loop, feeder length
and the presence of metal reinforcing beneath the loop.
The nature of the applicaon determines the required sensivity, which may be adjusted by means of the Sensivity
DIP switches as indicated on the detector.
Mulple sensivity levels have been provided in the PD27x Series Detector, making it one of the more sensitive
detectors available. The detecon of small unwanted objects such as bicycles and trolleys may be eliminated by selecng
lower sensitivity levels while high-bed vehicles and vehicle/trailer combinaons will not lose detecon by using
Automac Sensivity Boost (ASB) opon.

307UM0200_01 May 2016 PD27x User Manual Page 12 of 30
ASB operates as follows: When ASB is disabled, the un-detect level is dependent on the sensivity setting of the
detector. Hence as the detector is made less sensitive, the un-detect level will reduce accordingly. When ASB is enabled
the un-detect level is xed irrespecve of the sensivity seng and will be equivalent to the un-detect level when the
sensivity is on maximum seng.
4.3 Types of Outputs
When a relay is congured as a presence output, it will produce a connuous output during the presence of a vehicle
over the inducve loop. When congured as a pulse output, the relay will output a pulse on detect according to the
pulse duraon seng.
For the PD27x both relays can be congured to operate as either a presence output relay or a pulse output relay, And
for both the user can select them to operate either is fail safe or fail secure mode.
Presence Relay Programming
Fail Secure Fail Safe
Relay
Un detect Closed Open
Detect Open Closed
Fault Closed Closed
Power O Closed Closed
Figure 5. Relay output configuration options
In fail-safe, the output is the same in detect as it is with no power applied to the unit. Either a valid detect situaon, or
a power failure/ fault will provide a signal. In fail-secure, the output is the same in un-detect as it is with no power
applied to the unit. Only a valid detect situation will provide a signal.
4.4 Response times
The response time of the detector is the time taken from when a vehicle moves over the loop to when the detector
gives an output.
The response mes of the PD27x have been adjusted to prevent false operaon in electrically noisy environments, but
retain adequate response to vehicles in parking and vehicle access control applicaons.
The response time will be proporonal to the level of sensitivity, the level of the detect and the speed of the vehicle. In
other words, a fast moving large detect will respond quicker than a slow moving small detect. Also, if the sensitivity is
set very low, the point at which it crosses the threshold will be later than higher sensivity sengs. At maximum
sensivity the response me is slower than other sensitivity levels to prevent false operation from noisy environments.
4.5 Powerfail
The PD27x is designed with a Powerfail feature that allows it to remember its operang condions and detect status in
the event of power being removed. When power is restored, the unit connues operang from its saved condions and
status. This is designed specifically for fail safe situations to retain the output state and prevent a glitch on the outputs
for a power failure. As such, when the power is restored the detector will not retune and will instead return to the
detect state prior to the power failure. If a vehicle was on the loop during the power failure, it will remain detected
when the power is restored. Thus it prevents the tuning out of a vehicle over the loop during a power failure.
The memory retenon of the vehicle is designed to be innite, but is subject to the following limitaons:

307UM0200_01 May 2016 PD27x User Manual Page 13 of 30
The level of the detect must be suciently greater (at least 0.8%) than the sensivity level or else the maximum
potenal temperature drifrom one time of day when the power fails to another when the power returns mustn’t
exceed 20°C.
The level of the detect should be no less than 0.15% and a minimum of 0.8% above the sensitivity level.
With AFS acvated, none of the channels must be in fault since this will cause the unit to retune on recovery.
If the presence of a vehicle should occur less than a second before power is lost, there is a chance that the unit won’t
retain the detect and the outputs could toggle on restoration of power.
If these condions are not met, it is possible for the detect condion to be lost on recovery of power.
Powerfail cannot be guaranteed to work if a user interferes with the detector in any way when the power
is OFF. No sengs are allowed to be changed. The enclosure housing the detector shall NOT be opened
when the unit is OFF and Powerfail is turned on, as any drastic change in temperature could result in
Powerfail starting up in the incorrect state. Nortech accepts no responsibility or liability in the event of
incorrect behaviour caused by user interference.
4.6 Automatic Frequency Selection
AFS allows the detector to briey evaluate all five frequency bands and select the best operang frequency available. It
weighs up each selecon based on where the frequency is located within the operaonal range, the signal strength, and
the level of detected noise. AFS allows the detector to evaluate all the frequency selecons.
Due to the increased processing required, AFS takes longer to tune than when it is deacvated. The tune me with AFS
on can range from 5 to 20 seconds. If aer this period of time, the detector sll has not tuned, it is also possible that
none of the frequency selections are suitable for the loop. If this occurs, manual frequency selecon should be used.
Due to the sporadic nature of noise, the channel may seem quiet during the evaluaon but sll suffer from cross-talk.
AFS can be toggled on or off via the DIP switch. While the detector is tuning, it is recommended to allow the AFS tuning
to complete.
On both manual and automatic frequency selecon, once a valid frequency offset has been selected, the detector waits
for that seng to sele below the sensitivity setng before allowing normal operaon to connue. If there is sufcient
drifrom an extreme temperature change in the installaon locaon or vehicles driving over the loop at the me, it is
possible that the tuning will timeout, invalidate that frequency selecon and aempt to tune again. If the situaon is
very close to the limit, it is possible that it might tune as the drior noise goes back over the threshold and the unit
goes into detect just as it tunes. In a noisy environment, this can be prevented by retuning and if the situation persists
to decrease the channel sensivity.

307UM0200_01 May 2016 PD27x User Manual Page 14 of 30
5. Installation guide
Opmum funconing of the detector module is largely dependent on factors associated with the inducve sensor loop
connected to it. These factors include choice of material, loop conguraon and correct installation pracce. A
successful inducve loop vehicle detecon system can be achieved bearing the following constraints in mind, and strictly
following the installaon instrucons. The detector must be installed in a convenient weather proof locaon as close as
possible to the loop.
5.1 Product Safety Requirements
•i) WARNING: The unit must be GROUNDED (earthed).
•ii) WARNING: Disconnect the power before working on the unit.
•iii) WARNING: On 120 VAC and 230 VAC models a readily accessible disconnect device
must be incorporated into the mains wiring (as per EN60950-1:2005 Secon
1.7.2.2).
•iv) WARNING: On all models the power supply to the unit MUST have short circuit protecon
and over current protecon installed at the power supply source (As per EN 60950-
1:2005 secon 1.7.2.3). Typically this will be a 5 Amp Magnec Circuit Breaker for
AC models and a fuse for DC models.
•v) WARNING: This product must be installed in an enclosure as the IP rang of the detector
is IP 30.
•vi) WARNING: No user serviceable parts inside. No internal sengs.
Warranty void if cover removed.
•vii) WARNING: Only use CE approved 11 pin relay bases such as Nortech Part No.
CTR119090 or equivalent.
As an alternative to the 11 pin relay base, Nortech has an 11 pin wiring harness,
Nortech Part No. 302FT0041, which can only be used in SELV voltage (less than 60
VDC or less than 42 VAC) applications.
5.2 Operational Constraints
5.2.1 Environmental Factors to Consider
Even though the PD27x Series parking detectors are housed, the system integrator MUST ensure that the detector is
installed in a housing/fire enclosure to protect it from the environment.
The PD27x Series parking detectors are rated to operate from -40°C to +80°C but the rate of temperature change MUST
not exceed 1°C per minute. This system integrator MUST ensure that the housing used complies with this rate of
temperature change requirement.
For installaon Outdoors refer to Appendix B.
For addional informaon on Environmental Factors refer to the secon “Environmental Inuences to Design
Parameters” in the “Loops and Loop Installations” Manual, Nortech Document No. MKT05.

307UM0200_01 May 2016 PD27x User Manual Page 15 of 30
5.2.2 Crosstalk
When two loop conguraons are in close proximity, the magnec elds of one can overlap and disturb the field of
another loop. This phenomenon, known as crosstalk, can cause false detects and detector lock-up.
Should the loops be connected to the same dual channel detector crosstalk will not occur, due to the fact that sequential
polling of the loops takes place, resulng in only one loop being energised at a given me.
Crosstalk between adjacent loops operang from different detector modules can be eliminated by:
1. Careful choice of operang frequency. The closer together the two loops, the further apart the
frequencies of operaon must be.
2. Separaon between adjacent loops. Where possible a minimum spacing of 2 metres between loops
should be adhered to.
3. Careful screening of feeder cables if they are routed together with other electrical cables. The screen
must be earthed at the detector end only.
4. Running feeder cables in their own slots, separated by at least 300 mm.
For addional informaon on Crosstalk refer to the secon “Crosstalk Prevenon” in the DU100 Diagnosc Unit User
Manual Nortech Document No. 895UM0001.
For informaon about resolving Crosstalk refer to the “Theory of Applicaon” secon in Diagnosc Unit DU100 User
Manual Document No. 895UM0001.
5.2.3 Reinforcing
The existence of reinforced steel below the road surface has the effect of reducing the inductance, and therefore the
sensivity of the loop detecon system. Where reinforcing exists 2 turns should be added to the normal loop, as referred
to in secon 5.4.
The ideal minimum spacing between the loop and the cable and steel reinforcing is 150mm, although this is not always
praccally possible. The slot depth should be kept as shallow as possible, taking care that no part of the loop or the
feeder remains exposed after the sealing compound has been applied.
5.3 Loop and Feeder Material Speci�ication
Extensive studies have been undertaken over the years by various agencies around the world in order to ascertain the
opmum loop installaon materials.
As an insulated conductor is a prerequisite, PVC covered cable has been used for many years as a rst choice, but tests
have shown, in fact, that this is unsuitable for long term installaons. The PVC tends to become porous with the result
that adjacent loops become electrically coupled to one another, with resultant crosstalk implications. Instability and
suscepbility to electrical interference can also result.
The insulaon must withstand wear and abrasion from the shifng streets, moisture, aack by solvents and oils, as well
as withstand the heat of high temperature sealants.
Silicone insulated cable has emerged as one of the preferred insulaon materials. Other insulaon materials are rubber,
thermoplasc, synthec polymer and cross linked polyethylene.
Stranded loop wire is preferred over solid wire. Because of its mechanical characteriscs, a stranded wire is more likely
to survive bending and stretching than a solid wire.
A heavy gauge conductor is denitely desirous in order to maintain the loop Q-factor. The loop and feeder should
preferably constute a single length of insulated multi-stranded copper conductor, with no joints and with the copper
having a minimum cross section 1.5 mm2. The feeder is twisted to minimise the effect of electrical noise.
Joints in the loop or feeder are not recommended. Where this is not possible, joints are to be soldered and terminated
in a waterproof juncon box. This is extremely important for reliable detector performance. Other forms of joins such
as those available in kits, where the joint is properly sealed against moisture, are also permied.

307UM0200_01 May 2016 PD27x User Manual Page 16 of 30
5.4 Sensing Loop Geometry
NOTE: 1) The circumference of the loop must not exceed 30 m.
2) The area of the loop must not exceed 30 m2and must not be less than 1 m2.
3) The loop must be constructed as detailed below.
Sensing loops should, unless site condions prohibit, be rectangular in shape and should normally be installed with the
longest sides at right angles to the direcon of trac movement. These sides should ideally be 1 metre apart.
Loops operang from the same detector module can share a common slot along one of the longer sides, if so required.
This type of configuration could be applied in a direcon logic applicaon. The maximum separaon permied for this
applicaon is 1 metre, ensuring that a vehicle can straddle both loops simultaneously in the required direcon of travel.
The only factor which governs maximum separation between loops in all other applications is the feeder length, with
100 metres being the maximum recommended length.
The length of the loop will be determined by the width of the roadway to be monitored. The loop should reach to within
300 mm of each edge of the roadway.
In general, loops having a circumference measurement in excess of 10 metres should be installed using two turns of
wire, while loops of less than 10 metres in circumference should have three turns. Loops having a circumference
measurement less than 6 metres should have four turns.
It is good pracce at me of installation to construct adjacent loops with alternate three and four turn windings.
For addional Informaon on loop geometry refer to the following documents:
•“INDUCTIVE LOOP VEHICLE DETECTION” - Nortech Doc. No. MKT0001.
•“TRAFFIC DETECTION” - Nortech Doc. No. MKT0002.
•“PARKING APPLICATIONS MANUAL” - Nortech Doc. No. MKT0003.
•“LOOPS and LOOP INSTALLATION” – Nortech Doc. No. MKT05
5.5 Loop Installation
All permanent loop installaons should be installed in the roadway by cung slots with a masonry cung disc or similar
device. A 45° crosscut should be made across the loop corners to reduce the chance of damage that can be caused to
the loop at right angle corners.
NOMINAL SLOT WIDTH: 4 mm
NOMINAL SLOT DEPTH : 30 mm TO 50 mm
A slot must also be cut from the loop circumference at one corner of the loop, leading to the roadway edge to
accommodate the feeder.
A connuous loop and feeder is obtained by leaving a tail long enough to reach the detector before inserng the cable
into the loop slot. Once the required number of turns of wire are wound into the slot around the loop circumference,
the wire is routed again via the feeder slot to the roadway edge.
A similar length is allowed to reach the detector and these two free ends are twisted together to ensure they remain in
close proximity to one another (Minimum 20 turns per metre) Maximum recommended feeder length is 100 metres. It
should be noted that the loop sensitivity decreases as the feeder length increases, so ideally the feeder cable should be
kept as short as possible.
The loops are sealed using a “quick-set” black epoxy compound or hot bitumen mastic to blend with the roadway
surface.

307UM0200_01 May 2016 PD27x User Manual Page 17 of 30
300 mm
300 mm
+/- 2 m depending on road width
1 m1 m
Min Distance Apart - 2 m (Road width = 2 m)
- 3 m (Road width = 4 m)
Max Distance Apart – No Limit
Figure 6. Adjacent loops connected to dierent detector modules
4 mm
30 – 50 mm
Figure 7. Slot details

307UM0200_01 May 2016 PD27x User Manual Page 18 of 30
6. Con�iguration
WARNING: 1. The connector PIN assignments vary from model to model.
Refer to the label on the side of the unit for connector PIN
assignment.
WARNING: 2. The wiring harness is only rated for SELV voltages (less than
60V DC or 42V AC). If the relays are to switch higher
voltages use CE LVD approved 11 pin sockets.
WARNING: 3. The wiring harness wire colour to PIN No. assignment
shown below only applies to wiring harness Part No.
302FT0041. Other wiring harnesses will have different wire
colour to PIN No. assignments.
6.1 PD271 Enhanced Detector - Order number 307FT0203
11-pin connector wiring for PD271 DETECTOR - Order number 307FT0203
302FT0041 Wiring Harness
Wire COLOUR
11 PIN Connector
Pin No.
FUNCTION
Red 1 Live Power supply
120V AC ± 10% 50/60Hz
Black 2 Neutral
Blue 3 Channel 1 Loop Twist this pair
Blue 4 Channel 1 Loop
Yellow 5 Channel 2 Loop Twist this pair
Yellow 6 Channel 2 Loop
Grey 7 Channel 2 Relay
Grey 8 Channel 2 Relay
Green/Yellow 9 Earth
White 10 Channel 1 Relay
White 11 Channel 1 Relay
6.2 PD272 Enhanced Detector - Order number 307FT0201
11-pin connector wiring for PD272 DETECTOR - Order number 307FT0201
302FT0041 Wiring Harness
Wire COLOUR
11 PIN Connector
Pin No.
FUNCTION
Red 1 Live Power supply
230V AC ± 10% 50/60Hz
Black 2 Neutral
Blue 3 Channel 1 Loop Twist this pair
Blue 4 Channel 1 Loop
Yellow 5 Channel 2 Loop Twist this pair
Yellow 6 Channel 2 Loop
Grey 7 Channel 2 Relay
Grey 8 Channel 2 Relay
Green/Yellow 9 Earth
White 10 Channel 1 Relay
White 11 Channel 1 Relay

307UM0200_01 May 2016 PD27x User Manual Page 19 of 30
6.3 PD274 Enhanced Detector - Order number 307FT0202
11-pin connector wiring for PD274 DETECTOR - Order number 307FT0202
302FT0041 Wiring Harness
Wire COLOUR
11 PIN Connector
Pin No.
FUNCTION
Red 1 Live Power supply
12-24V ± 10% DC/AC
Black 2 Neutral
Blue 3 Channel 1 Loop Twist this pair
Blue 4 Channel 1 Loop
Yellow 5 Channel 2 Loop Twist this pair
Yellow 6 Channel 2 Loop
Grey 7 Channel 2 Relay
Grey 8 Channel 2 Relay
Green/Yellow 9 Earth
White 10 Channel 1 Relay
White 11 Channel 1 Relay
Figure 8. Example of PD27x Side Labels. Power supply requirements and pin connecons are clearly stated on the side of the
unit. 11 Pin configuration is shown on the le, DIN Rail on the right.
6.4 PD271 Enhanced Detector DIN Rail - Order number 307FT0206
DIN Rail connector wiring for PD271 DETECTOR - Order number 307FT0206
6 PIN Connector
Pin No.
FUNCTION
Top
1 Channel 1 Loop Twist this pair
2 Channel 1 Loop
3 Earth
4 Channel 2 Loop Twist this pair
5 Channel 2 Loop
6 Not Connected
Boom
7 Channel 2 Relay
8 Channel 2 Relay
9 Channel 1 Relay
10 Channel 1 Relay
11 Power supply
120V AC ± 10% 50/60Hz
12

307UM0200_01 May 2016 PD27x User Manual Page 20 of 30
6.5 PD272 Enhanced Detector DIN Rail - Order number 307FT0207
DIN Rail connector wiring for PD272 DETECTOR - Order number 307FT0207
6 PIN Connector
Pin No.
FUNCTION
Top
1 Channel 1 Loop Twist this pair
2 Channel 1 Loop
3 Earth
4 Channel 2 Loop Twist this pair
5 Channel 2 Loop
6 Not Connected
Boom
7 Channel 2 Relay
8 Channel 2 Relay
9 Channel 1 Relay
10 Channel 1 Relay
11 Power supply
230V AC ± 10% 50Hz
12
6.6 PD274 Enhanced Detector DIN Rail - Order number 307FT0208
DIN Rail connector wiring for PD274 DETECTOR - Order number 307FT0208
6 PIN Connector
Pin No.
FUNCTION
Top
1 Channel 1 Loop Twist this pair
2 Channel 1 Loop
3 Earth
4 Channel 2 Loop Twist this pair
5 Channel 2 Loop
6 Not Connected
Boom
7 Channel 2 Relay
8 Channel 2 Relay
9 Channel 1 Relay
10 Channel 1 Relay
11 Power supply
12-24V ± 10% DC/AC
12