Working With Modbus Devices; Assigning Modbus Slave Ids - Banner Sure Cross DXM1200-Bx Instruction Manual

7 Working with Modbus Devices

The DXM1200 has two physical RS-485 connections using Modbus RTU protocol.
The master Modbus RS-485 port is for the DXM1200 to act as a Modbus master device to control internal and external
Modbus slave devices. The Modbus master RS-485 port uses the white (+) and black (-) wires on the M12/Euro-style quick
disconnect connector.
Ethernet
RS-485 (master)
Internal
Micro USB
The DXM1200 operates the Modbus master port. Each device on the master port must be assigned a unique slave ID.
There are slave IDs that are reserved for internal devices in the DXM1200.
Modbus Slave ID Device
1 DX80 Performance Gateway or MultiHop ISM Radio—MultiHop wireless devices connected to the internal MultiHop radio
should be assigned Modbus Slave addresses starting at 11.
199 Local Registers—Internal storage registers of the DXM1200
201 LCD—The user has access to the LED indicators on the DXM1200.

7.1 Assigning Modbus Slave IDs

Set the DXM Slave ID from the LCD menu under System > DXM Slave ID. The DXM1200 can have any unique slave ID.
DXM Master Configuration—When the DXM1200 operates as a Modbus master device, use the DXM Configuration
Software to configure read or write operations of the DXM Modbus network. The DXM1200 communicates with all internal
and external peripheral devices using the external Modbus bus RS-485.
There are four internal Modbus slave devices that are configured from the factory with slave IDs. Assign slave IDs of 2
through 10 to Modbus slave devices that are physically wired to the DXM1200. Assign slave IDs or 11 through 60 to
wireless slaves within the MultiHop network.
Do not assign a slave ID of greater than 10 to Modbus slave devices that are physically wired using the RS-485 port if there
is an internal MultiHop ISM radio in the DXM1200. The MultiHop ISM radio attempts to send any Modbus data intended for
slaves 11–60 across the radio network, which conflicts with wired slave devices if the slave IDs overlap. The MultiHop
master radio can be changed from the factory default of 11–60 Modbus slave IDs if more hardwired slaves are required.
Processor/Outputs (Base Board)
Local Registers
(Modbus ID 199)
Local Regi sters
Integer
Local Registers
Float
Local Registers
Non-Volatile
Processor Controlled
Cellular Modem
Modbus Data Traffic
Control
Figure 15. DXM1200 system overview
DXM Internal Modbus Slave IDs (factory default)
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Sure Cross DXM1200-Bx Wireless Controller
ISM Radio (Modbus ID 1)
Gateway or MultiHop
User Display (Modbus ID 201)
LED / LCD Display
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