Elster Solutions URF01 User Manual

UNIVERSAL RADIO FREQUENCY

INTERROGATOR (URFI) USER’S MANUAL

(PRELIMINARY VERSION)

AMERICAN METER COMPANY

AUTOMATED SYSTEMS BUSINESS UNIT

107 ERSKINE LANE

SCOTT DEPOT, WEST VIRGINIA 25560

Overview

The Universal Radio Frequency Interrogator® (URFI®) is a portable radio transceiver
used in conjunction with any customer-supplied handheld or portable computer to
provide remote meter reading of Trace® system transponders. The Trace system is
designed to convert the mechanical index reading of a utility meter to a duplicate
electronic register reading. This electronic register reading is transmitted via radio
frequency (RF) signals to the URFI. The URFI reads each transponder b y means of an
RF interrogation that consists of a unique serial number along with a command
requesting the contents of the electronic register. The meter reading route data, which
contains the street address and serial number of each transponder that is to be read, is
stored by the computer, as is the actual meter reading following a successful
interrogation; no data is stored in the URFI itself.

The URFI is controlled by a number of commands sent from the computer. Primary
functions controlled by the computer’s route-reading application are: initiation of
interrogation; setting of receiver channel; and setting of power up/down modes.

A typical interrogation sequence consists of the following.

1. The computer powers up the URFI and the URFI performs its initialization routine,

which includes programming the receiver and transmitter frequency synthesizers.

2. The computer sends the serial number of the transponder to be interrogated to the

URFI through a serial port connection.

3. The URFI transmits a synchronization data pattern followed by the transponder serial

number. This transmission is approximately 1.5 seconds in length.

4. A transponder ‘wakes up’ at some point during the URFI’s synchronization data

pattern transmission, hears the serial number and replies with the meter reading data
if the serial number heard matches its own. Otherwise, the transponder goes back to
sleep.

5. The URFI receiver listens for the transponder reply. If no valid data is d etected, the

receiver scans a range of adjacent channels for valid data. In this way, the receiver
finds a drifted transponder signal, and the URFI sends the transponder channel to the
computer; the URFI then re-interrogates with its receiver set to the new channel.

6. When the URFI receiver receives a valid transponder reading, this data is passed from

the URFI to the computer for storage.