Spread Spectrum Wireless Data Transceiver User Manual
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L
OWPOWER
M
ODE
The Lowpower Mode is an option that, when enabled, allows the transceiver to function as a MultiPoint
Slave while consuming less power. This is achieved primarily by dimming the transceiver's LEDs. When
set to 2 through 63, the transceiver will sleep between slots. For example, at a setting of 2 the transceiver
sleeps 1 out of 2 slots, at a setting of 3 the transceiver sleeps 2 out of 3 slots, and so on.
I
MPORTANT
N
OTES
1.
The Lowpower Mode is for use only in MultiPoint Slaves. The power savings occur when the
option is enabled and the Slave is connected to the Master or a Repeater. There are no power
consumption savings when the Slave is transmitting data to the Master. Designed primarily for
SCADA systems, the Lowpower Mode is of little value when significant amounts of data need to
be sent from the Slave to the Master. The MCUSpeed must be set to ‘0’ and RF Data Rate must
be set to ‘3’ in order for the LowPower mode to operate properly.
2.
Additional power savings may be realized when the number of Repeaters is set to 1 throughout
the network, even if no Repeaters are being used.
3.
To communicate to a RS232 port of a transceiver that is in Lowpower Mode, the RTS line must
be held high to wake it up. The transceiver will wake up within approximately 20 milliseconds of
when CTS goes high.
4.
If the RTS line on the Slave is held high, the transceiver will remain in normal operation
regardless of the Lowpower Mode setting. Once RTS is dropped it will go back into the preset
lowpower mode.
5.
If the transceiver has DTRConnect option set to 1 or 2 and if the LowPower mode is set to
anything higher than 0 (activated), then in order for the ‘DTRConnect’ feature to operate properly,
RTS line on the transceiver has to be asserted.
The following table shows the changes at different Lowpower Mode settings. The actual current draw
depends on many factors, so the table gives only qualitative indication of savings of supply current. A low
number reduces latency, and a high number reduces current consumption.
Setting
Description
0 Low-power,
disabled
1
LEDs dimmed, transceiver remains awake, transceiver is
listening to the master’s transmissions on every slot,
transceiver’s data port is shut down if the RTS line is
deasserted (low). So, even in this case, the transceiver
needs to be awakened before it will be able to send data
to the master.
2
LEDs dimmed, transceiver sleeps every other slot
3
LEDs dimmed, transceiver sleeps 2 of 3 slots
4-63
LEDs dimmed, transceiver sleeps number of slots
corresponding to setting. For example, with a setting of 63
the transceiver is sleeping during 62 of the slots.
Current Draw
More
Less
(A)
H
IGH
N
OISE
Use this setting to indicate if the transceiver will be operated in an environment with high radio noise or
interference. With a setting of 1, the rejection of interference is improved, but at the cost of reduced range
and/or throughput. This setting is most effective with out-of-band-noise.
LUM0002AD Version
6.1
39
