Operations Manual

EXI HALO Installation & Operation Manual 981-000003-000
EXI Wireless Systems 17 March 2000
Revision 2.0
Take note of the following:
• Ensure that no tag can reach the protected area without passing through a field.
• The field should not extend into other rooms or areas that are regularly occupied by tags. These tags
could keep a controller in a pre-alarm state preventing the door from opening if magnetic door locks
are being used.
• The tag should be detected at least 4 feet from the door in order to give the magnetic door lock time to
energize.
• Proximity to other fields could also be a factor. If a Tag is able to receive communication from 2
different controllers in the case of field overlap, it will try to respond to both controllers. Each
controller will see Tag communication when it doesn’t expect it and report it as noise, thereby
inhibiting any alarms..
• The antenna should be located be at least 18” away from metal objects, cables, air ducts etc. in order to
be able to create a uniform field with minimal loss of RF power.
Ceiling height, door approach width and metal in the vicinity, need to be considered when planning the location
for the exciter antennae. The field should extend to the floor and cover the entire exit way. A dropped ceiling
consisting of a grid and non-foil backed ceiling tile are the easiest construction materials to work with. Check
above the lay-in tile to see how much space you have and the proximity of metal objects such as pipes, cables
and air plenums. The SRA may also be dropped inside a wall cavity. Sometimes it’s simpler to mount the SRA
on the side of a wall above the door or along the hallway about 5 feet from the floor.
Extensive metal close to the Exciter can distort the field in unpredictable ways. Metallic objects will absorb
and/or reflect radiated energy, which affects the field. This phenomenon can increase or decrease the field
strength in areas causing hot spots or holes in your field. It can even change the shape of the field with tag
detection sometimes occurring as much as 35 ft away. At times this effect can be used to advantage but the
desired result can only be determined experimentally.
Although it is not possible to completely predict the performance of the field for every situation, some
information about the field will help to shorten the process of determining the best location for the SRA. In the
absence of any site irregularities, the field is symmetrical, perpendicular to the antenna length. A cross-section
through the length of the antenna is roughly oval as shown below.
Although the field strength is adjustable, the maximum distance for good coverage is approximately 10 feet.
Sometimes 2 exciters are necessary to get adequate coverage.
5.6. LOCATING THE RECEIVER ANTENNA
The “RX” Antenna should be mounted in a vertical plane. The “RX” Antenna is provided with a removable
right angle fitting that facilitates the desired mounting position. The area to be protected has to be blanketed
by controllers and receivers so that all critical areas have coverage. Elevator Interfaces cannot be included in
the area calculations since the elevator is not always on the floor. Walls, equipment and excess metal could
affect the pickup range. Although greater distances are possible, a maximum of 40’between devices is
recommended.
If it’s not possible to create a proper field with the exciter inside,
an SRA-E exciter antennae could be placed on an outside wall to
limit the penetration of the field into the building.
Watch out for foil
backed ceiling tile!
Note: The coax cable used is RG59U with a solid copper center conductor and shield. SEA
exciters draw current therefore do not use ordinary RG59U cables to extend the length supplied as
they used copper clad steel.