FreeWave Technologies Inc. 1293514195135 Manual De Usuario
LRS400S Data Transceiver Users Manual
LUM0025AA Rev A
Version 1.0
20
On the other hand, the function in the Master is effectively the same. With a setting of 255, the Master
will allow a Slave to stay connected as long as 1 packet in 255 is successfully received at the Master.
will allow a Slave to stay connected as long as 1 packet in 255 is successfully received at the Master.
The Retry Time Out parameter is useful when a MultiPoint network has a roving Master or Slave(s). As
the link gets weaker, a lower setting will allow a poor link to break in search of a stronger one.
the link gets weaker, a lower setting will allow a poor link to break in search of a stronger one.
Note: Setting Retry Time Out to 20 is recommended in areas where several FreeWave networks exist.
This setting will allow Slaves to drop the connection if the link becomes too weak, while at the
same time prevent errant disconnects due to interference from neighboring networks.
same time prevent errant disconnects due to interference from neighboring networks.
While intended primarily for MultiPoint networks, the Retry Time Out parameter may also be modified in
Point-to-Point networks. However, the value in Point-to-Point mode should not be set to less than 151.
Point-to-Point networks. However, the value in Point-to-Point mode should not be set to less than 151.
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L
OWPOWER
M
ODE
The Lowpower Mode feature allows a MultiPoint Slave to consume less power. 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 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.
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.
Setting Description
0 Lowpower,
disabled
1
LEDs 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.
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
LEDs dimmed, transceiver sleeps every other slot
3
LEDs dimmed, transceiver sleeps 2 of 3 slots
4-31
LEDs 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.
the setting. For example, with a setting of 31 the transceiver sleeps 30 of
31 slots.
I
MPORTANT
N
OTES
1.
Lowpower Mode is used only in MultiPoint Slaves using serial protocol. Power savings occur only
when the Slave is linked. There are no power savings 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.
when the Slave is linked. There are no power savings 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.
To communicate to an 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 RTS goes high.
be held high to wake it up. The transceiver will wake up within approximately 20 milliseconds of
when RTS goes high.
3.
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.
regardless of the Lowpower Mode setting. Once RTS is dropped the transceiver reverts to the
Lowpower Mode.
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.
31), the RTS line on the transceiver must be asserted for the ‘DTRConnect’ feature to operate properly.
Current Draw
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