TransCore encompass 4 - Reader and Tag Alignment

Encompass 4 Reader System Guide
2-4
Group (IAG) tags. The reader can read the A
TA or ISO read-only tags in the presence
of Intellitag-based tags; however, attempting to read an Intellitag-based tag in the
presence of an ATA or ISO read-only tag is not recommended.
Caution
Attempting to read an Intellitag-based tag in the presence of an ATA or ISO read-only
tag may
provide unreliable results.
The factors that influence the readability include, but are not limited t
o physical orien-
tation and configuration, type of read-only tag, ratio of
backscatter cross-section of the
tags, and whether the tag is battery- or beam-powered.
Reader and Tag Alignment
The position of the Encompass 4 Reader and placement of the tag on the vehicle must
be compatible. Also, consider any existing tagged vehicles now using the facility to
determine the optimal Encompass 4 Reader location and orientation at the site.
Note: If any of
the vehicles using your facility already have tags, such as those used
in toll applications, contact TransCore for information about mixed-tag installations
before you plan tag type, location, and programming.
Three primary criteria must be satisfied to
achieve the highest read reliability:
• Polarization of the tag and the Encompass 4 Reader must be aligned in the same
direction
— both horizontal.
• The installed tag must be in a direct, unobstructed line of sight to the Encompass 4
Reader.
• Tags designed to be mounted in a vehicle windshield must be mounted in the vehi-
cle’s windshield, and tags designed to be mounted on the exterior surface of the
ve
hicle must be mounted on the exterior surface of the vehicle.
Caution
A tag may not be reliably read unless the preceding criteria are met.