Nortech DU 100 User manual

DU 100
USER MANUAL
NORTECH
All rights reserved
Copyright ©2000
Document No. : 895UM0001-02
Date of issue : May 2001
Nortech International (Pty) Ltd
P O Box 4099 32A Wiganthorpe Road
Willowton Hub Pietermaritzburg
Pietermaritzburg 3201 South Africa
3200 South Africa Reg. No. 98/10951
Tel: [phone] Int. Tel: [phone]
Fax: [phone] Int. Fax: [phone]
Email: m[email protected]a URL: www.nortech .co.za

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Table of Contents
1. INTRODUCTION............................................................................................ 3
2. TECHNICAL SPECIFICATIONS……………………………………….
3. OPERATIONAL INSTRUCTIONS.....................................................……
4
3.1 Intelligent Power Control...........................................................................….. 4
3.2 Display Contrast/Viewing Angle…………………………………………….
3.3 Data Acquisition……………………………………………………………..
4
5
3.4 DiagnosticOperation...................................................................................…. 5
4. OPERATIONAL MODES............................................................................. 6
4.1 Loop (Loop).................................................................................................... 6
4.2 Frequency (Freq)............................................................................................. 7
4.3 Sensitivity (Sens)............................................................................................. 8
4.4 Status (Stat)..................................................................................................... 9
4.5 Time (Time).................................................................................................... 10
4.6 Crosstalk (Xtlk)............................................................................................... 11
4.7 Built In Self Test (Test)................................................................................. 13
5. THEORY OF APPLICATIONS................................................................... 14
5.1 Loop Frequency and Inductance Change........................................................ 14
5.2 Loop Frequency Drift....................................................................................... 15
5.3 Detection Sensitivity........................................................................................ 16
5.4 Detector Status................................................................................................ 16
5.5 Historical Fault Data........................................................................................ 17
5.6 Crosstalk Prevention....................................................................................... 18
6. APPENDIX A – TYPICAL VALUES……………………………………… 19

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. INTRODUCTION
The Nortech DU100 Diagnostic Unit is a hand held test instrument capable of
providing installation/service personnel with positive verification of the correct
operation of a vehicle detector installation. It may only be utilised in conjunction with
diagnostic compatible vehicle detector products from Nortech Industries.
Current operational and historical data are transferred form the vehicle detector to the
DU100 by means of an optical link. Data transmission form the vehicle detector unit
occurs continuously so no service disruption is necessary. Received data is verified
for integrity by means of a cyclic redundancy check (CRC), processes, and then
displayed on a LCD screen.
1.1 The DU100 can be used with the following inductive loop detectors;
PD130, PD139 (excluding I²C models), PD140, PD230, PD239 (excluding I²C models),
PD240, TD136, TD136 Enhanced, TD250, TD250L, TD250LS, TD252.
1.2 Related Documents
“Inductive Loop Vehicle Detection” Document No. MKT01.
1.3 This manual covers the following units;
895FT0001 – DU100 Diagnostic unit – English
895FT0002 – DU100 Diagnostic unit – German
895FT0003 – DU100 Diagnostic unit – French
895FT0004 – DU100 Diagnostic unit – Italian
895FT0005 – DU100 Diagnostic unit - Spanish

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2. DU100 TECHNICAL SPECIFICATIONS
Frequency Resolution 1Hz
Sensitivity Resolution 0.001 % ∆L/L
Display Element 2 line x 16 Character LCD
Display Contrast Adjustable via multi-function keyswitch
Keyswitch 1 x Mode Selection, 1 x Power-on/execute
Auto Power off 2 Minutes after last operation
Optical Receiver Detachable wand with photo-diode
Power Supply 4 X 1.5V AA dry cell
Battery Life > 10 hours continuous
Operating Temperature Range 0°C to + 50 °C
Dimensions 200mm (h) x 100mm (w) x 40mm (d)
Weight 380gms including batteries
3. OPERATIONAL INSTRUCTIONS
3.1 Intelligent Power Control
The DU100 Diagnostic Unit may be powered-up by pressing either the SELECT or
ENTER key. The unit may be turned off by the simultaneous pressing of both keys.
Automatic power-down will occur after the unit has been left unused after two
minutes.
3.2 Display Contrast/Viewing Angle
The display contrast may be adjusted by holding down either key: SELECT for
lighter, ENTER for darker.

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3.3 Data Acquisition
Data is extracted form the vehicle detector under test by means of a unidirectional
optical link. An optical wand ( normally located in the zippered side pocket of the
DU100 bag) should be plugged into the jack socket at the top of the unit and the unit
should be powered-up. When the optical wand is brought into close proximity of the
red “RUN LED” of the detector under test, the DU100 will emit audible beeps as it
acquires data. A single beep received indicates that sufficient data has been received
and the optical link may be broken at this stage to enable operator interrogation.
Alternatively, the optical link may be maintained in order to facilitate continuous data
transfer and updating.
3.4 Diagnostic Operation
After pressing any button and powering the diagnostic unit, information can be
acquired ( indicated by an audible beep ). The DU100 will display the type of the
vehicle detector under test ( e.g. PD130 ) and its software release version on the top
line of the two display screen. The lower line will consist of a cyclical menu. Each
time the SELECT key [¤] is pressed, the cursor will jump to the next menu option.
Menu options, once selected, are activated by means of the ENTER key[ ↵].

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4. OPERATIONAL MODES
Each operational mode corresponds to a menu option. These are discussed below.
4.1 Loop (Loop)
e.g.
The loop frequency and change in inductance are displayed for the currently selected
channel. The currently selected channel is displayed in the top right hand corner. This
mode can be used to monitor the change in loop frequency and inductance as a vehicle
traverses the loop.
SELECT [¤] advance to the next detector channel ( multi-channel units only ).
ENTER [ ↵] returns control to main menu.
The inductance change (%∆L/L) is a measure of the magnitude of detection. Typical
passenger vehicles register a peak change of the order of 1% - 3% ∆L/L. Poorly
designed loop installations can lead to this value being significantly reduced.
Below are typical inductance changes (%∆L/L) for a loop measuring 2m x 1m and
having 3 turns; with no wire mesh re-inforcing.
VEHICLE TYPE ∆L/L
BICYCLE 0.04 %
MOTORBIKE 0.12 %
ARTICULATED TRUCK 0.38 %
FOUR WHEEL DRIVE 0.40 %
5 TON TIP TRUCK 0.45 %
MOTOR CAR > 1.00 %
FORKLIFT > 1.00 %
The inductance change parameter can also be utilised to determine whether the
inductance change registered by a particular vehicle ( e.g. high undercarriage of a
commercial vehicle ) is of sufficient magnitude to break through the sensitivity
threshold of the vehicle detector. The relevant sensitivity threshold value may be
obtained from the detector data sheet and is typically 0.02% ∆L/L.
KHZ % ∆L/L 1
20.231 1.371
Channel
Fre
q
uenc
y

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4.2 Frequency ( Freq )
e.g.
The loop frequency and frequency drift ( since last reset/retune ) are displayed for
the currently selected channel. The currently selected channel is displayed in the top
right hand corner. The drift measurement gives an indication of the quality of a loop
installation.
Note: The drift value is an historical value and is cleared each time the detector
resets/retunes.
SELECT [¤] advances to the next channel ( multi-channel units only ).
ENTER [ ↵] returns control to the main menu.
The loop frequency value represents the frequency of the AC signal energising the
inductive loop and should be in the range of 20 KHz - 150 KHz. It is determined both
by switch settings on the detector and loop geometry ( size and no. of turns ). Loops
in close proximity to one another require a frequency spacing of greater than 2KHz
typical to avoid crosstalk ( not necessary for multiplexed multi-channel detectors ).
The frequency drift is used to determine the quality of the loop and feeder cable
typically the frequency drift should be less than 3 %. Typically frequency drift of
greater than 0.1 % per minute (typical) will cause a detect.
Factors affecting frequency drift are:
•Mechanical movement of loop wires.
•Deterioration of loop wire insulation allowing penetration of moisture.
•Temperature variation of the loop environment.
[Refer to Section 5.2]
KHz Drift 1
20.231 0.20%

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4.3 Sensitivity ( Sens )
e.g.
The minimum and maximum change in the loop inductance during vehicle detection
are displayed for the currently selected channel. The currently selected channel is
displayed in the top right hand corner. These values represent absolute minima and
maxima and are valid since the last detector reset/retune.
Note: MIN and MAX are historical values which are cleared each time the detector
resets/retunes. Their value will remain at zero until the first detect.
SELECT [ ¤] advances to the next channel ( multi-channel units only ).
ENTER [ ↵] returns control to the main menu.
The maximum value (MAX) corresponds to the greatest magnitude of detection for all
vehicles since the last reset of the vehicle detector. If the vehicle detector is manually
reset before the loop is traversed by a vehicle, the MAX display will indicate the
highest detection level over the profile vehicle. Typical levels for a passenger vehicle
are 1% - 3% ∆L/L. As the sensitivity of the installation can be severely degraded by
poor layout or proximity of ferrous metal, this value is useful for site-to-site
comparisons ( i.e. using the same vehicle ).
The minimum value (MIN) indicates the smallest magnitude of inductance change
( resulting in a detect ) for all vehicles, since the last reset of the vehicle detector. Over
a relatively short span of time, this value will tend towards the sensitivity setting of
the vehicle detector.
A detection change of greater than 15 % (typical), will cause the detector to re-tune.
( A change greater than 15 % is considered a fault condition ).
MIN MAX 1
0.110% 3.401%

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4.4 Status ( Stat )
e.g.
The loop status of the currently selected channel is displayed. The currently selected
channel is displayed in the top right hand corner.
Possible loop status conditions include:
i. Undetect
ii. Detect
iii. Open circuit
iv. Short circuit
v. Indeterminate
SELECT [ ¤] advances to the next detector channel ( multi-channel units only )
ENTER [ ↵] returns control to the main menu.
Open circuit status will also be caused by a loop inductance of greater than
1500uH 2000uH (typical).
Short circuit status will also be caused by a loop inductance of less than
20uH (typical).
STATUS Chan : 1
( undetect )

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4.5 Time ( Time )
e.g.
Elapsed time ( in days and hours ) since the last reset/retune and the reason for the
reset/retune are displayed.
This information is particularly useful for detecting intermittent faults which are self-
healing.
Possible reasons for reset/retune include:
i. Reset: manual reset ( pushbutton ) or power failure
ii. Short circuit
iii. Open circuit
iv. Indeterminate
v. Inductance change of greater than 15 % ∆L/L (typical).
SELECT [ ¤] advances to the next detector channel ( multi-channel units only )
ENTER [ ↵] returns control to the main menu.
10 D 5 H 1
( Reset )