OBID
®
Installation
ID AWE 3000/6000.A-A
FEIG ELECTRONIC GmbH
Page 39 of 55
H40591-4de-ID-B.doc
E N
G
L I S H
Induction loops for cheque card transponder
Length [cm]
Width [cm]
No. of turns
Inductivity [µH]
10
10
ca. 33
300 ±5%
15
15
ca. 27
300 ±5%
20
20
ca. 22
300 ±5%
25
25
ca. 20
300 ±5%
30
30
ca. 16
300 ±5%
Chart 2:
recommended induction loop sizes
FEIG ELECTRONIC GmbH offers you a great variety of finished loops, which are easy to install
and visually attractive.
10.3.5. OBID
®
-ground antennas for vehicle transponder
OBID
®
ground antennas either consist of a figure-eight induction loop or two separately installed,
prefabricated induction loops. The latter is used for installation under pavement. Therefore, OBID
®
-
ground antennas do not detect vehicle transponder in center above one loop section, but between
the two. In order to facilitate data transmission, the vehicle transponder ID CTF.A-A have to be
aligned with their longitudinal axis in the direction of motion.
Both loop parts of the ground antenna have the same size and number of turns. They have to be
installed one after the other (in the direction of motion) with a distance of 0,3m to 0,5m. Each in-
duction loop has to be between 125
µ
H and 165
µ
H (incl. supply line inductivity).
It is very important, that the loops are installed in a way that the transponder, which is mounted in
the vehicle is entering the detection area whenever it crosses the antenna (illustr.1). Please make
sure that the vehicle is detected only if the detection area is crossed in the given directions. The
marked detection area does not have the same width as the antenna. It is indented from each side
by approx. 30cm.
If need be, the crossing has to be guaranteed by constructional measures.
In order to adapt the ground antenna to the local conditions of the roadway, the dimensions of the
two loop parts may to a certain extent be selected with regard to their length L, width B and dis-
tance A. The ideal width B results, if a distance of 0,25 m is kept at each side. However, it must not
exceed 3 meters. The length L of each loop part in the direction of motion must not exceed 1 me-
ter. The distance A between the loop parts is limited to a maximum of 0,5 meters.