User's Manual

CHAPTER 3 VRT DIRECT GAS-METER TRANSPONDER OVERVIEW
VRT Gas Transponder ― User Guide Page 9
AMCO Automated Systems • P/N 52870T010 Rev 1 May 2003
How the VRT Direct Gas-meter Transponder
Works
When a VRT DGT is installed on a meter the installer programs the
mechanical index reading into the transponder.
Converting Mechanical Count into Electronic Form
During normal operation, the mechanical index accumulates its
count. The transponder keeps track of the index reading by counting
the number of rotations of the index’s drive dial.
Storing Readings
Once a day, at a pre-programmed time specified by the utility, the
transponder stores the current index reading into the electronic
index for that day.
The transponder maintains daily reading history for the past 35
days.
Four time-of-use registers—each with programmable start and stop
times—can accumulate consumption in separate electronic indexes
as well.
Operation Cycle
To maximize battery life, the VRT gas-meter transponder changes
from its normal, low-power quiescent state every 1.5 seconds into
an intermediate power state for 2.5 milliseconds in order to perform
three tasks:
• Update the electronic indexes for the meter reading, daily
reading and time-of-use reading
• Poll the tamper detection switch
• Check to see if a valid interrogation signal is being received
If and when a valid interrogation signal is received, a two-way
communication link is established.
Meter reading data is then transmitted to the interrogator.
Data collected by an interrogator is validated and stored for
uploading to TRACE Route Manager VRT Software later.
VRT Direct Gas-meter Transponder Programmed
Values
At the time of manufacture transponders are programmed with the
current date, time of day, and other values as specified by the utility.
Each type of data shown in the table below may be programmed/
recorded at some or all of the following four stages: