User's Manual

455U Radio Modem Module User Manual
Page 40 © November 2004
AT&L1 – Go directly online at startup
AT&U1 - Set Modem’s address to 1
AT&Z0=0,0 - Set all messages to go to the wildcard address, and repeat once
4.7.2.2 Slave Repeater stations address 2 and 3
AT&M0 - Configure mode 0 – Unacknowledged mode.
AT&L1 – Go directly online at startup
AT&U2 (or &U3)- Set Modem’s address to 2(or 3)
AT&Z0=1 - Set all messages to go directly to master station, address 1.
AT&R1 - Set Broadcast Repeater mode – Repeat messages on first hop to wildcard address 0.
ATS17=20 or 40 – Set the receive hold-off to a different value for each repeater. This ensures
that the repeated messages from the repeaters don’t clash with each other. Also this ensures
the repeated messages don’t clash with responses from any of the directly communicating
devices. This command sets one repeater to 200 mSec hold-off and the other to 400 mSec
hold-off.
4.7.2.3 Slave device Site address 4
AT&M0 - Configure mode 0 – Unacknowledged mode.
AT&L1 – Go directly online at startup
AT&U4 - Set Modem’s address to 4
AT&Z0=1 - Set all messages to go directly to master station, address 1.
4.7.2.4 Slave device Site addresses 5 and 6
AT&M0 - Configure mode 0 – Unacknowledged mode.
AT&U5(or U6)- Set Modem’s address to 5(or 6)
AT&P0=:1 - Set all messages to go directly to master station, address 1..
4.7.3 Modbus Network, including repeaters
This example applies to both a modbus network and to a DF1 half duplex network. The
difference will be the of &M setting (mode).
The application requires the following configuration
• Master station. modem address 99 (No modbus address).
• Remote stations 1-4 communicate directly to master station. Modbus addresses 11-14
are connected to these stations.
• Remote stations 5-6 communicate to master station through remote station 3. Modbus
addresses 25-26 are connected to these stations.
• Remote station 7 communicates to master station through remote stations 6 and 3.
Modbus address 27 is connected to this stations.
4.6.2.1 Master station configuration