User Manual

Global Transceiver Module (GXM) Wireless Data Transceiver User Manual
LUM0031AA
Version 1.0 34
(9) LOWPOWER MODE
The Lowpower Mode feature allows a MultiPoint Slave to consume less power. This is achieved primarily
by dimming the transceiver's LED’s. When set to 2 through 31, 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.
The following table shows the changes at different Lowpower Mode settings. The actual current draw
depends on many factors. The table below gives only a qualitative indication of supply current savings. A
low number reduces latency and a high number reduces current consumption.
Current Draw
Setting Description
0 Lowpower, disabled
1
LED’s dimmed, transceiver remains awake, transceiver is listening to the
Master’s transmissions on every slot, and transceiver’s data port is shut down
if the RTS line is deasserted (low). In this case, the transceiver needs to be
awakened before it will be able to send data to the Master.
2 LED’s dimmed, transceiver sleeps every other slot
3 LED’s dimmed, transceiver sleeps 2 of 3 slots
4-31
LED’s dimmed, transceiver sleeps the number of slots corresponding to the
setting. For example, with a setting of 31 the transceiver sleeps 30 of 31 slots.
More
Less
I
MPORTANT NOTES
1. Lowpower Mode is used only in MultiPoint Slaves using serial protocol. Power savings occur only
when the Slave is linked. No power savings occur when the Slave is transmitting data. Lowpower
Mode is of little value when a Slave has a constant, high throughput. MCUSpeed must be set to
‘0’ and RF Data Rate must be set to ‘3’ for Lowpower Mode to operate properly.
2. Additional power savings may be realized when the Number Repeaters is set to 1.
3. To communicate to the data 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 RTS 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 the transceiver reverts to the
Lowpower Mode.
5. If the transceiver has the DTRConnect option set to 1 or 2 and if the Lowpower Mode enabled
(set to 1-31), the RTS line on the transceiver must be asserted for the ‘DTRConnect’ feature to
operate properly.
(A)
HIGH NOISE
The High Noise Option is useful in determining if out of band interference is affecting a radio link. A
setting of 1 will provide a reduction of gain in the front end circuit thereby decreasing the affect of any out
of band noise. The results will be seen as a lower signal value and a much lower noise value (as found in
Radio Statistics or Diagnostics). If the noise is not reduced by a greater amount than the signal, the
interference is most likely an in band issue.
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