User's Guide

©WhereNet Corp September 2006D1312r01 WhereTrack Users Guide 28September07.doc Page 5
WhereTrack WNC Unit
The WhereTrack is a custom WhereNet product that supports 802.11b/g WiFi, GPS, and the WhereNet Real Time
Locating System (RTLS). It is a medium sized device that can be attached to a variety of CPE such as UTRs, RTGs,
FELs, STs and SGs. A PACECO PTIU is generally, but not always, also installed on the CPE. If the CPE has a PTIU, the
WNC connects to the PTIU via EtherNet and forwards the PTIU telemetry information to the RTLS through tag
transmissions and provides WiFi back haul connectivity. Some CPEs, such as Quay Cranes, may not require a PTIU, but
may still require a WNC unit. In this case, the WNC provides the function of periodic GPS and RTLS location reporting.
The PTIU is a custom Paceco product that supports a number of digital and analog ports. The PTIU is installed on a
variety of CHE. It’s primary function is to detect the state of sensors, to determine container transition events, and to
report these to the WhereNet MTS SW stack. The PTIU generally connects to sensor signals already available on the
CHE as well as a variety of new sensors installed on the CHE. In some cases, the PTIU also connects to the CHE PLC in
order to obtain the sensor data it requires.
The WNC contains the functionality of 4 internal STHO WhereTags that can be set to "blink" an RF transmission at pre-
programmed rates ranging from 0.5 seconds to one hour between blinks. The WhereNet RTLS infrastructure receives
these blinks and use sophisticated Differential Time of Arrival, (DTOA), algorithms to determine the location of the tag.
Accuracy of this determined location can be as low as 2 meters and is nominally within 3 meters in most installations.
The tag blink data field can also include the GPS locate information as well as other telemetry information that is
connected to the WNC from the CPE. The WNC is also assigned an individual MAC address.