ABB LWT300 Series User Manual page 65

subject to a plausibility check.
Immediately after receipt of the transmitter or after changing the configuration, we recommend that
you back up the existing configuration on a separate data medium.
An RS485 interface will be needed for communication between a PC and the transmitter.
• The driver for this interface must support a COM port.
• The software communication tool must be set to the same COM port as the RS485 interface.
• The baud rate for configuration of the transmitter is fixed to 1200 baud and must be set to the same
value inside the communication software tool.
• The communication protocol of the transmitter has to be set to 'CONFIG/HART-RS485' with the HMI
or the dip switches (dip switches 3 and 4 to position 1; see Figure 44 below).
For operating with a Modbus master after configuration, the transmitter must be set back to
'OPERATE/MODBUS' with the HMI or the dip switches (dip switch 4 to position 0).
Before starting configuration via a software communication tool, the transmitter function must be
switched from 'Operate' to 'Configuration' mode (using the HMI) (see "Toggling communication
modes" on page 67).
—
Figure 44 Modbus communication board
1
0
1 Dip switches
NOTICE
Settings configured via DIP switches always have priority over the ones set with the
HMI. For more information on these parameters, see "Configuring communications" on
page 67.

1
ON
0
1 2 3 4
P/N : 3KXL001060U0400
NV FORMAT
1
ENABLE
DISABLE
0
PROTOCOL MODE
ENABLE
CONFIG / HART-RS485
OPERATE / MODBUS
DISABLE
MODBUS
TM
Configuring the instrument
1
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