User's Manual

Table Of Contents

EA Mobile User Guide

6. Reading mode

Establishing Lat/Lon coordinates

For new routes whose endpoints have not yet been assigned coordinates, the

FIFO Mode is recommended. Once a endpoint is located and responds, the GPS

can then provide latitude and longitude information to be stored along with other

account information. For routes having many endpoints both with and without

coordinates, the GEO mode is recommended, as it streamlines the search for

endpoints that have coordinates while allowing for unassigned endpoints to be

interrogated and their coordinates assigned. Interpolated Lat/Lon (captured by

the EA_Mobile) are the coordinates of the EA_Mobile when the interrogation is

validated, however, these coordinates may be up to 1500 ft away from the actual

endpoint position. Therefore, for optimal performance hard coded Lat/Lon

coordinates taken at the endpoint are recommended.

Using Lat/Long coordinates

The GPS receiver provides latitude and longitude coordinates for the EA_Mobile-

equipped vehicle. Based on this position, the EA_Mobile can calculate which

endpoints should be in the interrogation window of the system. It then sends out

interrogation signals looking for only those endpoints. When all endpoints in the

interrogation window (IW) have been read, you can continue on the route.

FIFO option In the FIFO option, the system considers all endpoints to be within the

interrogation window at all times. The FIFO method does not require Lat/Lon

coordinates for either the endpoints or the EA_Mobile/vehicle. Instead it simply

reads through the route list over and over as you drive the route, scanning for all

unread endpoints on the list.

• This is the slowest Reading option, especially at the beginning of a session.

As endpoints report their data, the list becomes shorter and thus the search

for unread endpoints proceeds more and more quickly.

Figure 6-3.

Use the FIFO option for the following situations:

L/L

L/L L/L

L/L

FIFO option continuously

selects for interrogation

ALL unread transponders

in the route, regardless of

coordinates or location.

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