User Manual

FlexNet SmartPoint Radio Overview A-3
SmartPoint Module for the Elster A3 Meter ECMTM40000
A.3.1 Normal Mode
Normal mode, as its name implies, is the preferred mode of transmitter operation for the SmartPoint
when the SmartPoint is operating in a 25 KHz channel (13.6 KHz if operating under FCC Part 90
Rules). Normal mode is utilized by the SmartPoint for the RF path from the SmartPoint to the TGB.
Three normal mode communication methods are used to collect SmartPoint™ meter data, Staggered
Transmissions, Real-time, and Poll-respond, as described briefly below.
A.3.1.1Staggered Transmissions
Hourly and daily meter read messages and bulk status information transit times are determined via
time randomizations to cause the network to behave like an ALOHA-modeled network:
• Data required on a daily basis (Normal mode 111 ms), 20 tower receivers
can read 1.4 million hourly meters.
• Real-time, Report-by-exception, Status and Alarm Information
• Data generally required in seconds or minutes:
• If power available (240 VAC or battery):
• Alarms reported immediately;
• Alarms reported redundantly (1 to 32 times until Ack).
• If power not available (limited to capacative power supply):
• 3 to 6 redundant transmissions occur in dialated time intervals,
• 30 sec. average initial message report, and
• Faster reporting intervals can be selected (application dependent).
A.3.1.2Poll-response Message Traffic
• Data generally required in real-time (Poll 158 ms and Respond 111 ms,
50 bytes):
• C&I meter traffic,
• Demand reads, and
• SCADA/Distribution Automation.
A.3.2 Poll/Response Mode
Poll/Response mode is the preferred mode of transmitter operation for the SmartPoint when the
SmartPoint is operating in an authorized bandwidth narrower than 20 KHz.
Poll/Response mode is identical to Normal mode with the exception that its data rate and its deviation
is one-half of Normal mode, and is utilized by SmartPoint devices for the RF path from the SmartPoint
to the TGB.
A.3.3 mPass or “Buddy” Transmit Mode
mPass (message pass) Transmit Mode allows a meter that cannot reach a TGB directly to use its
neighboring two-way SmartPoint modules to repeat its message. Generally, communications between
meters and FlexNet tower-mounted receivers is not a problem because of FlexNet tower heights.
However, in some few installations, the meter-to-tower signal path may be obstructed by objects that
significantly attenuate the SmartPoint transmitter signal.
A single TGB can cover 70,000 SmartPoint devices, dependant upon meter and TGB
configuration.