User's Manual
Table Of Contents
- FreeWave Technologies
- LRS-455-EU
- Data Transceiver
- Version 1.0, Revision A
- About FreeWave Transceivers
- Choosing a Location for the Transceivers
- Quick Start on a Point-to-Point Network
- Setting up a Transceiver
- Operation Mode
- Baud Rate
- Modbus RTU Timing
- The Modbus RTU setting causes the radio to wait for an amount of time, “gathering” data before sending out the radio link.
- With a setting of 0 (Disabled), the radio will send data out its radio link as soon as the data is received into the serial port.
- With a setting of 1, the radio will wait for a number of slots equal to 2 times the Master Packet Repeat setting before sending the received data out the radio link. For example, if Master Packet Repeat = 3, the radio will wait for 6 slots, gathering ...
- With a setting of 2 and higher, the radio will wait for a number of slots calculated by the following formula:
- (Modbus RTU Setting + Master Packet Repeat Setting + 1) x 2
- For example, in a radio where the Modbus RTU setting = 2 and the Master Packet Repeat setting = 3, the radio will wait for (2+3+1) x 2, or 12 slots.
- Call Book
- Radio Transmission Characteristics
- Edit Radio Transmission Characteristics
- MultiPoint Parameters
- Edit MultiPoint Parameters
- Radio Information
- Operational RS-422 and RS-485 Information
- RS232 Pin Assignments
- RF Board Pinout
- FreeWave Technical Support
- Errata
LRS-455-EU Data Transceiver Users Manual
LUM0032AA Rev A Version 1.0 15
Packet Size (0), the time will be approximately 5.9 ms. Please note that this latency can increase
significantly if packets are lost between the Master and Slave. In Point-to-MultiPoint mode, there is no
absolute guarantee that the state change will be communicated to all Slaves in the unlikely event that all
repeated packets from the Master do not get through to all Slaves.
Note: If DTRConnect is enabled and set to 2, the RTS to CTS feature will not work.
Note: If the DTRConnect is enabled and set to 1, RTS to CTS mode takes precedence over the
functionality of the CTS line on the Slave relating to the DTRConnect feature.
Note: The RTS to CTS option is only available in RS232 mode.
(8)
RETRY TIME OUT
The Retry Time Out parameter in a Slave sets the delay the unit will wait before dropping the connection
to a Master in MultiPoint mode. The factory default is set at the maximum of 255. The maximum setting
means that if 1 packet in 255 is sent successfully from the Master to the Slave, the link will be maintained.
The minimum setting is 8. This allows a Slave to drop a connection if less than 1 in 8 consecutive packets
is successfully received from the Master.
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.
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.
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.
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.
(9)
LOWPOWER MODE
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 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.