Magnetic Autocontrol MHTM MicroDrive Access Series, Operating Instructions Manual

Page: 57 / 144

Barrier MHTM
TM
MicroDrive Access and Parking
Assembly and installation
5815,5013US / Version 05 57
Please observe following points when installing the induction loop:
Loop geometry and clearances

Install the loop symmetrically to the barrier arm. Please make
sure that the barrier arm is attached to the side of the barrier
housing.

The clearance of the safety loop for passenger cars in front of,
and behind the barrier arm must be at least 19.7 in (500 mm).
The safety loop for trucks must be dimensioned larger. → See
page 29, Fig. 4 to page 35, Fig. 6.

The distance of the induction loop from the roadside should be
about 11.8 in to 19.7 in (300 to 500 mm).

Install opening loops right in front of the safety loop. The
clearance between opening loop and safety loop must be not
greater than 3.28 ft (1 m) for trucks and passenger cars.

If there are iron reinforcements, ramp heating etc. in the
roadway, the induction loop must have a clearance of at least
1.97 in (50 mm) from those. Metals in the proximity of the
induction loop affect the response sensitivity.

Avoid direct contact of induction loops with reinforcement and
ramp heating.

Install induction loops with sufficient clearance from sliding
gates, roller grilles etc.
Installation and ground conditions

Please make sure when moulding or installing that the loop can
not move anymore once it is in operation. Any geometric
alteration will act as inductance change, which will set the
detector to an error state.

Brittle road surfaces, loose pavements, gravel paths etc. are not
suited for the application of induction loops.
Feed line

The feed line to the loop must not exceed 49.2 ft (15 m).

The loop connection cable must protrude about 4.9 ft (1.5) m
from the foundation.

Shorten the feed line to the loop to the proper length. The feed
line must by no means be coiled.

The feed line must be twisted up to right in front of the terminals
of the loop detector with ca. 6 twists per feet.