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895UM0001_02 

DU100 User Manual 

Page 19 of 19 

  

6. 

Appendix A – Typical Values 

 

Detector 
Model 

Frequency of 
Operation 

Inductance  Change 
%

L/L 

Drift 

Sensitivity %

L/L 

 

MIN MAX  MIN 

MAX 
before 
retune 

MAX 

less 

than 

MIN MAX 

Typical 20KHz 

150 

KHz 

0.02 %

L/L 6 

%

L/L 

3% 

0.02 to 0.5 %

L/L 

0.03 to 6 %

L/L 

 

 

 

 

 

 

 

 

Parking 
Detectors 

12KHz 85KHz  0.02 %

L/L 6%

L/L 

3 % 

0.02 to 0.5 %

L/L 

0.03 to 6%

L/L 

 

 

 

 

 

 

 

 

Traffic 
Detectors 

15KHz 140KHz  0.02%

L/L 6%

L/L 

3% 

0.02 to 0.5 %

L/L 

0.03 to 6%

L/L 

 

Содержание DU 100

Страница 1: ...e 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 033 345 3456 Int Tel 27 33 345 3456 Fax 033 394 6449 Int Fax 27 33 394 6449 Email mkt nortech co za URL www nortech co za ...

Страница 2: ... 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 1...

Страница 3: ...m 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 I C models PD140 PD230 PD239 excluding I C models PD240 TD136 TD136 Enhanced TD250 TD250L TD250...

Страница 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 wi...

Страница 5: ...es 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 th...

Страница 6: ...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 0...

Страница 7: ...l 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 t...

Страница 8: ...r 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...

Страница 9: ...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 ...

Страница 10: ...articularly 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 ...

Страница 11: ...tored when the Enter 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 button is pressed e g Upon each successful data capture by the DU100 a result of the crosstalk will be automatically displayed If the same channel of the the same detector is re captured the test will fail as the result will be based ...

Страница 12: ...nel multi channel units only ENTER returns control to the 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 Loops in close proximity to one another require a frequency spacing of greater than 2 kHz typical to avoid crosstalk not necessary for channel...

Страница 13: ...ation 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 ...

Страница 14: ...ge change in inductance L 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 L L is a measure of the sensitivity of the loop detector installation For a given vehicle the value will b...

Страница 15: ...ged 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 in figure 4 1 Figure 4 1 Loop capacitance coupling in roadway slot This capacitance is directly proportional to the dielectric constant of the slot ...

Страница 16: ...ll 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 should be driven over the loop to determine the level of cha...

Страница 17: ...Fault The detector will then determine the characteristics and nature of the fault and wait for the problem to be corrected 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 tim...

Страница 18: ...or the loading effect of the loop caused by the reinforcing 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 The loop feeder should ideally be a twisted pair with a low series resistance so that the feeder does not reduce sensitiv...

Страница 19: ...uctance Change L L Drift Sensitivity L L MIN MAX MIN MAX before retune MAX less than MIN MAX Typical 20KHz 150 KHz 0 02 L L 6 L L 3 0 02 to 0 5 L L 0 03 to 6 L L Parking Detectors 12KHz 85KHz 0 02 L L 6 L L 3 0 02 to 0 5 L L 0 03 to 6 L L Traffic Detectors 15KHz 140KHz 0 02 L L 6 L L 3 0 02 to 0 5 L L 0 03 to 6 L L ...

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