Installation Manual

EXI HALO Installation Manual Rev 2.0
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EXI Wireless Systems Inc. Page 11 June, 1999
3.1.2. TEST CONTROLLER AND SET UP FIELDS
After reading Section 3.2 on LOCATION FOR SEA EXCITER ANTENNAS, choose a suitable
location for the SRA. Setting up a field is a matter of trial and error. The primary considerations
here are the field shape and strength. The field has to fill the area in front of the door all the way to
the floor so that no tag can reach the door without being detected.
To set up a field, start by placing the tag at the range you want for the field at the height a tag is
usually going to be found. The tag needs to be detected far enough from the door to allow the
magnetic door lock time to energize. The tag should be placed on a non-metallic surface for test-
ing. You might want to do a preliminary field setup by holding the SRA at the approximate loca-
tion you want to install it but be aware that your body could be affecting the field. The SRA should
be temporarily placed and the field adjusted for range using this stationary tag. Since the Tag will
be read easier in some orientations with respect to the SRA, it is also necessary to test with the Tag
in a variety of positions.
With the SRA and tag in position use the SRA RANGE ADJUST control on the top right corner of
the controller circuit board to set up your field strength. Turn the control shaft clockwise all the
way to the end for maximum field range. If the device is not beeping at this point, the SRA will
need to be repositioned. Once the SRA is positioned so that the device is beeping, turn the control
shaft counter clockwise slowly until the beeping stops. Then return clockwise approximately 1/16
of a turn or so that the beeping resumes. Repeat this process for various orientations of the Tag.
Make sure the Tag can be read in any position.
Now that the field range is set up, you need to determine the shape and consistency of the field.
SOME NOTES ON SENSITIVITY: All radio frequency (RF) devices are sensitive to po-
larization. Everyone has had a portable radio that got much louder if it was positioned at a
particular angle. Another example is the TV antenna on your house. If you turned your TV
antenna on it’s side, you would receive a weaker signal and the deterioration of picture
quality would be dramatic if the TV signal you received was already marginal.
Unfortunately all other RF receivers suffer from the same electronic phenomenon. The
Roam II Tag has to first receive from the controller before it will transmit its serial number.
We can expect that there will be better response from the tag in one orientation. A strong
field will ensure that even an improperly oriented Tag will respond.
The most important aspect of the entire installation is the correct positioning of the
SRA Exciter Antenna. A little time spent here will save countless hours of frustration
and service calls later.
Apply double-backed foam tape to the side of the antenna to temporarily attach it to a
vertical surface for testing purposes. Take care that the antenna doesn’t fall as sudden
hard jolts may render it useless.