DU100 User Manual - FindTheNeedle.co.uk
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1. lt gt hortech DU100 USER MANUAL ISSUE 03 5 2 Loop Frequency Drift This is a measure of the quality of loop installation The display of drift value in Frequency mode represents the absolute difference between the current loop frequency and the reference loop frequency defined at the last reset retune Abnormal values of loop frequency drift can indicate a loop installation of poor quality Drift occurs primarily as a result of changes in ambient temperature and should normally be less than 3 Values significantly greater than 3 are generally indicative of loops of poor quality Potential causes include damaged insulation low resistance earth path ingression of moisture and movement of loop wires Ingression of moisture also results in increased loop frequency drift Capacitive coupling exists between loop turns and the side walls of the loop slot as shown below Loop capacitance coupling in roadway slot This capacitance is directly proportional to the dielectric constant of the slot sealing material If this material is hygroscopic readily absorbs and retains water or incomplete does not fill the slot or encapsulate the wires allowing water to enter the slot and penetrate between loop conductors the capacitance will change greatly due to the high dielectric constant of water This change in loop capacitance will shift the loop operating frequency thus causing loop frequency drift to increase Page2. and cause the detector to lock up and no longer function The problem also exists when reinforcing used to strengthen a structure is in close proximity to the loop It provides an efficient means of coupling two loops together Crosstalk can be eliminated by following a few simple steps e Always ensure separation between loops when planning a new site Where possible ensure a minimum distance of 2 metres between loops e When using non multiplex detectors change the number of turns between adjacent loops by one or two turns if a number of loops are being installed e When reinforcing is present the number of turns should be increased by two or more to compensate for the loading effect of the loop caused by the reinforcing e There will be a loss in sensitivity The loop should also be mounted as far from the reinforcing as possible typically 150mm Care should be taken to ensure that no loop cable is exposed after sealing compound is applied e The loop feeder should ideally be a twisted pair with a low series resistance so that the feeder does not reduce sensitivity The twisting of the feeders is especially important as this will counteract the effects of noise and crosstalk form adjacent feeders and power cables Typical twists are greater than 1 turn per 3 centimetres 33 twist per metre e Once detectors have been connected and powered up the loop frequencies must be measured to check frequency separation between loops When only
3. nortech DU100 User Manual REF No UG DU100 ISSUE 03 August 2009 lt nortech DU100 USER MANUAL ISSUE 03 Contents To INTOPUCON DE 3 1 1 Compatible Deiechors ce c ccc ccceecceccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeess 3 1 2 Related Documents 3 1 3 Models Covered 0 cece cceccceccceccceecceeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeneeeeeeeneeeeeeeeeeeeeeeeeeeeeeess 3 2 DU100 Technical Gpechfcatons 4 3 Operational Instructions cc cccecceeeeeeeceeeeeeeeeaaeaaaeeaaeaaaeaaaaaaeeaaaaaaeaaaeeeaeaeaeeeeeeaeeeeseeeseeseeeeseees 5 3 1 Intelligent Power Control eebe ageet 5 3 2 Display Contrast Viewing Angle cccccecesceeennnee eee eeeneeceeneeeeeeeeeeeesneeneeneeeeeeeessnseenneceeeeens 5 3 3 Data ee UE en E 5 Ke Te ee E 5 4 OPERA TIONAL MODES iitsdectxecerintlsotcarndeasncedicenotiankadetssdatdeaisenedaassantilend iexbeldusbdacataescsimeasinbes 6 4 1 Loop e EE 6 42 Ee E 7 e EE ET EE 8 AA Status Stat esris ranan EE N Eara VaN EEEE ONNEA E Eaa E 9 4 5x Kin TE 10 46 CGr sstalk IR E 11 4 7 Built In Self Test Test EE 12 5 JREORY OF AP PEC A TION MEN 13 5 1 Loop Frequency and Inductance Change cccccccceeeceeneceeceeeeneeeeseneeeneeeeeeeeeeneeeenseeeeee 13 5 2 Loop Frequency Dm 14 5 3 Detection SensitiVity TE 15 5 4 Detector Status A 15 59 Historic al Fault Dataren ila ea eee 16 5 6 Crosstalk Prevention ccccceeeeceeeeeee
4. 14 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 5 3 Detection Sensitivity Detection sensitivity may be defined as the threshold level at which the smallest change in inductance results in an output actuation This is clearly dependent on the inductive loop characteristics and may be adjusted by the sensitivity switch setting on the detector itself With the detector set to maximum sensitivity relatively smaller changes in inductance result in detection Detector sensitivity settings are designed such that maximum sensitivity should be capable of detecting all vehicles while lower settings would eliminate detection of bicycles supermarket trolleys and the over hang of high bed vehicles Maximum and minimum values as shown in the DU100 sensitivity menu correspond to the largest and smallest changes in inductance resulting in detection since the last time the detector was reset manual or power reset The desired level of sensitivity may be achieved by comparison between recorded changes and sensitivity switch settings at a particular site Over a process of time the minimum value which will approach the demanded sensitivity threshold of the detector thus confirming this selection To reliably determine which sensitivity level should be used at any particular site the sensitivity level of the detector should be set to maximum to ensure that all vehicles are detected A variety of vehicles matching the types used on the site sho
5. The channel to be stored can be changed by pressing the Select button if the detector is a multi channel unit The frequency of the channel indicated in the top right hand corner will be stored when the Enter Lal button is pressed This value becomes the reference until the mode is cleared and re entered The following menu will be displayed after the Enter Lal button is pressed e g CROSSTALK Test Upon each successful data capture by the DU100 a result of the crosstalk will be automatically displayed If the same channel of the same detector is recaptured the test will fail as the result will be based on the original value e g CROSSTALK Test PASS CROSSTALK Test FAIL The test uses the original stored frequency and compares it to the new successful samples If the frequency is too close in proximity to the stored value the test will fail SELECT advance to the next detector channel multi channel units only ENTER 4 returns control to main menu This mode allows comparison of loop frequencies for potential crosstalk situations on a pass fail basis The comparison can however be manually investigated as described under loop frequency Page 11 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 Loops in close proximity to one another require a frequency spacing of greater than 2 kHz typical to avoid crosstalk not necessary for channels connected to the same multiplexed multi channel detecto
6. one multiplex detector is used this does not need to be done If more than one detector is used this is crucial Record the frequencies and check that there is at least 2000Hz separation between all loops in close proximity to one another Note that this situation can be severely aggravated by the presence of steel reinforcing below the road surface Page 16 of 17 O nortech DU100 USER MANUAL ISSUE 03 Appendix A Typical Values Detector Frequency of Inductance Change Drift Sensitivity Model Operation AL L AL L MAX MAX MIN MAX MIN before less MIN MAX retune than Typical 20KHz 150Khz 0 02 AL L 6 AL L 3 0 02 to 0 03 to 0 5 AL L 0 6 AL L Parking 12KHz 85Khz 0 02 AL L 6 AL L 3 0 02 to 0 03 to Detectors 0 5 AL L 0 6 AL L Traffic 12KHz 140KHz 0 02 AL L 6 AL L 3 0 02 to 0 03 to Dette 0 5 AL L 0 6 AL L Page 17 of 17
7. e g STATUS Chan lt Undetect gt 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 ll Detect Ill Open circuit IV Short circuit V Indeterminate SELECT advance to the next detector channel multi channel units only ENTER 4 returns control to main menu Open circuit status will also be caused by a loop inductance of greater than 1500uH to 2000uUH typical Short circuit status will also be caused by a loop inductance of less than 20uUH typical Page 9 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 4 5 Time Time e g 10D 5H lt RESET gt 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 push button or power failure Il Short circuit Ill Open circuit IV Indeterminate V Inductance change of greater than 15 AL L typical SELECT advance to the next detector channel multi channel units only ENTER 4 returns control to main menu Page 10 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 4 6 Crosstalk Xtlk First level screen awaiting first data capture e g CROSSTALK Store
8. ee eee eee sees sees eee eeeeeeeeeeeeeceeeseeeseeeseeeeeeeeeeeeeeeeeeeeeees 16 Appendix A Typical Values eneen eent aen rten rnerr nen tnen rnern rnern nnen nn nannt nann nnn nannan nannan annann ne 17 Page 2 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 1 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 from the vehicle detector to the DU100 by means of an optical link Data transmission form the vehicle detector limit 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 Compatible Detectors The DUI 00 can be used with the following inductive loop detectors PD130 PD139 excluding FC models PD140 PD230 PD239 excluding PC models PD240 TD136 TD136 Enhanced TD250 TD250L TD250LS TD252 1 2 Related Documents Inductive Loop Vehicle Detection Document No MKT01 1 3 Models Covered This manual covers the following units 895FT0001 DU100 Diagnostic unit English 895F T0002 DU100 Diagnostic unit German 895FT0003 DU100 Diagn
9. es and reverts the state to undetect Undetect If the loop connected to the detector was disconnected or shorted due to failure the detector would immediately log this occurrence and change states to loop fault Loop Fault The detector will then determine the characteristics and nature of the fault and wait for the problem to be corrected Page 15 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 5 5 Historical Fault Data Historical Fault will display the last recorded fault by the detector as well as the time elapsed since the last fault If no fault has occurred during the detector s operation the fault status will be RESET and the time displayed will be from the time the detector was last powered lip or the reset push button was pressed If a loop fault occurs then the fault will be recorded and the elapsed time since the fault occurred to the current time will be displayed to the nearest hour Even if the loop fault no longer exists the event will remain until the next fault occurs The loop fault will be displayed as either Short Circuit or Open Circuit An open circuit indicates that the loop has been disconnected wire continuity broken A short circuit indicates that the loop has been shorted at some point 5 6 Crosstalk Prevention When two or more loop configurations are in close proximity the fields of one loop can interfere and disturb the field of another This phenomenon known as crosstalk can cause false detects
10. gged 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 PD 130 and its software release version on the top line of the two line 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 Lal Page 5 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 4 OPERATIONAL MODES Each operational mode corresponds to a menu option These are discussed below 4 1 Loop Loop e g Channel dL L 1 371 Frequency 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 monit
11. he 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 advance to the next detector channel multi channel units only ENTER 4 returns control to 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 a vehicle traverses the loop the MAX display will indicate the highest detection level over the profile vehicle Typical levels for a passenger vehicle are 1 3 AL 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 Page 8 of 17 lt gt hnortech DU100 USER MANUAL ISSUE 03 4 4 Status Stat
12. n oscillator frequency Experience has shown that the percentage change of inductance AL L from an unoccupied loop to an occupied loop is extremely repeatable for a given loop size and geometry and for a given location of the vehicle with respect to the loop When operated in Loop mode the DU100 Diagnostic Unit displays both the absolute loop frequency and the percentage change in inductance AL L For the case of an unoccupied loop the percentage change in inductance will remain at zero small values may occur due to oscillator or loop drift A vehicle traverses the loop the change in frequency and inductance may be observed The percentage change in inductance AL L is a measure of the sensitivity of the loop detector installation For a given vehicle the value will be dependent on various factors including e Loop size e Loop depth below ground level e Amount of residual metal in close proximity to the loop Absolute loop frequency may be in the range of 12 kHz 150 kHz Change in inductance however is vehicle and installation dependent Its merit lies in comparisons between various vehicles at a particular site or between various sites with the same vehicle The relationship between absolute loop frequency and absolute loop inductance is exponential in nature and is dependent on the particular detector type Curves that define this relationship are available on request from Nortech for a particular detector type Page 13 of 17
13. or 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 4 returns control to main menu The inductance change AL L is a measure of the magnitude of detection Typical passenger vehicles register a peak change of the order of 1 to 3 AL L Poorly designed loop installations can lead to this value being significantly reduced Below are typical inductance changes AL L for a loop measuring 2m x 1m and having 3 turns with no wire mesh reinforcing VEHICLE TYPE AL L BICYCLE 0 04 MOTORBIKE 0 12 ARTICULATED TRUCK 0 38 FOUR WHEEL DRIVE 0 40 5 TON TIP TRUCK 0 45 MOTORCAR gt 1 00 FORKLIFT gt 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 AL L Page 6 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 4 2 Frequency Freq e g KHz DRIFT 20 231 0 20 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 co
14. ostic unit French 895F T0004 DU100 Diagnostic unit Italian 895F T0005 DU100 Diagnostic unit Spanish Page 3 of 17 O nortech DU100 USER MANUAL ISSUE 03 2 DU100 TECHNICAL SPECIFICATIONS Frequency Resolution Sensitivity Resolution Display Element Display Contrast Keys Auto Power off Optical Receiver Power Supply Battery Life Operating Temperature Range Dimensions Weight 1Hz 0 001 AL L 2 line x 16 Character LCD Adjustable via multi function keys 1 x Mode Selection 1 x Power on execute 2 Minutes after last operation Detachable wand with photo diode 4 x 1 5V AA dry cell gt 10 hours continuous 0 C to 50 C 200mm h x 100mm w x 40mm d 380gms including batteries Page 4 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 3 OPERATIONAL INSTRUCTIONS 3 1 Intelligent Power Control The DU100 Diagnostic Unit may be powered up by pressing either the SELECT or ENTER I 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 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 plu
15. rner 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 advance to the next detector channel multi channel units only ENTER 4 returns control to 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 number 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 The frequency drift should normally be less than 3 Typically a frequency drift of greater than 0 1 per minute will cause a detect Factors affecting frequency drift are e Mechanical movement of loop wires e Deterioration of loop wire insulation allowing penetration of moisture e Temperature variation of the loop environment Refer to Section 5 2 Page 7 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 4 3 Sensitivity Sens e g MIN MAX 0 110 3 401 The minimum and maximum change in loop inductance during vehicle detection are displayed for the currently selected channel The currently selected channel is displayed in t
16. rs 4 7 Built In Self Test Test The function of the self test is to check the diagnostic unit s functionality The first test will test the display and buzzer the screen will blink with all characters flashing and the buzzer being audible for this duration The next test is to verify that the EPROM the device which contains all the diagnostic information is not damaged the result being PASS or FAIL Below will be the checksum number of the EPROM which is used to verify the EPROM The next test is the RAM the device which contains all the working parameters and received information from the detector and this test will ensure that the RAM has no errors The result of the test being PASS or FAIL The last line of information returned from the test is the version number of the Diagnostic Unit The screen will then return to the normal operating mode Note The keys will be disabled during the tests and restored upon the test completion Page 12 of 17 lt gt hortech DU100 USER MANUAL ISSUE 03 5 THEORY OF APPLICATION 5 1 Loop Frequency and Inductance Change The inductive loop is energised by an AC signal that is produced by an oscillator in the vehicle detector The operating frequency of the oscillator is determined by both the physical characteristics of the loop and the frequency determining components within the detector When a vehicle enters the loop the loop inductance decreases causing a corresponding increase i
17. uld be driven over the loop to determine the level of change The vehicle with the lowest change on the MAX level of the DU100 sensitivity menu should be used to then determine the sensitivity threshold of the detector A threshold more sensitive than the observed change should be selected If a particular vehicle was to be excluded e g supermarket trolley then the threshold level selected on the detector would be less sensitive than the maximum change recorded for the vehicle 5 4 Detector Status Detector status may be defined as the current state the detector is operating in when the Diagnostic Unit takes the samples The first event that will occur after the detector is powered or a loop is connected and the Diagnostic Unit is receiving data is that the detector will begin to tune Tuning During this time the detector will determine the operating frequency of the loop connected and most suitable operating parameters to be applied to the loop Thereafter the detector will change to the undetect Undetect state During this time the detector will monitor the loop for vehicles as well as determine the temperature changes around the loop and detector and adjust the levels accordingly Upon a vehicle entering the loop and the threshold levels for detect being correct the state then changes to detect Detect The detector will then monitor the vehicle as it passes over the loop It will continuously monitor the vehicle until it leav
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