User's Manual

301UM0031_01 TD136 Enhanced Vehicle Detector User Manual Page: 24 of 29
8.2.1.5 Crosstalk
For information about resolving crosstalk refer to the “Theory of Application” section in Diagnostic
Unit DU100 User Manual Document No. 895UM0001
8.3 Functional Test
To test a detector, connect it to an inductive loop with a total inductance in order of 300 microhenries.
(This may be achieved in the workshop by winding (x) turns of wire on non-metal former of diameter
(y)).
X = 19 turns 0,25 mm wire
Y = 238 mm ( 9.4 inches )
Bring a small metal object approximately the size of a matchbox close to the loop coil.
The following will happen on detection:
The OUTPUT LED will light up
The PRESENCE output relay will operate
The PULSE relay will operate momentarily (approximately 150ms duration)
To check the sensitivity, presence time etc., a calibrated tester should be used, which compromises, of
a calibrated loop similar to the one described above with a moveable vane, which can be moved over
the loop at pre-determined heights.
This device together with the DU100 hand-held test instrument will allow comprehensive analysis of
the operating characteristics of the detector.