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As a Modbus RTU master device, the DXM controls external slaves connected to the primary RS-485 port, the local
ISM radio, local I/O base board, and the local display board.
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As a Modbus RTU slave device, the DXM local registers can be read from or written to by another Modbus RTU
master device.
The secondary port (S+/S-) is the Modbus RTU slave connection. The secondary (slave) Modbus RS-485 port (S+/S-) is
controlled by another Modbus master device, not the DXM. The slave port is used by an external Modbus master device that
will access the DXM as a Modbus slave device.
Use the configuration software to define operational settings for both the Modbus RTU master port and the Modbus RTU
slave port.
Use the DXM's LCD menu to set the Modbus Slave ID for the secondary RS-485 port.
5.11.1 Set the Master and Slave Port Parameters
The basic communications parameters for the RS-485 ports are set in the DXM Configuration Software and are saved in the
XML configuration file.
Figure 20. Settings > General screen
1. In the DXM Configuration Software, go to the
Settings
>
General
screen.
2. To set the parameters for the Modbus Master, change the settings in the
Master Port Settings M+/M-
section.
3. To set the parameters for the Modbus Slave, change the settings in the
Slave Port Settings S+/S-
section.
Baud Rate
Defined for both the Modbus master and slave
Settings include: 19200 (default), 1200, 2400, 9600, 38400, 57600, and 115200.
Delay between messages
Applies to the Modbus master port
Sets the minimum wait time from the end of a Modbus transaction to the beginning of the next Modbus transaction.
Parity
Defined for both the Modbus master and slave
Settings include: None (default), odd, even, space, and mark
Timeout
Applies to the Modbus master port
Covers the expected time for messages to be sent throughout the wireless network. For the DXM, the
Timeout
parameter is the maximum amount of time the DXM should wait after a request is sent until the response message is
received from the Modbus slave device.
Sure Cross
®
DXM150 and 1500-Bx Wireless Controllers
www.bannerengineering.com - Tel: + 1 888 373 6767
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