Installation guide
188 Modbus Plus Transaction Elements
890 USE 100 00
For messages to a single Modbus slave device connected to a Bridge
Multiplexer port: each nonzero byte except the last two specifies
routing through a Bridge Plus to another network. The last two
nonzero bytes specify the Bridge Multiplexer’s node address (164)
and Modbus port (14), respectively.
For messages to a Modbus networked slave device connected to a
Bridge Multiplexer port: each nonzero byte except the last three
specifies routing through a Bridge Plus to another network. The last
three nonzero bytes specify the Bridge Multiplexer’s node address
(164), Modbus port (14) and slave address (1247), respectively.
Modbus Frame (Modified)
This field contains the Modbus command originated by the controller,
or by a Modbus master device connected to the controller. Data in a
Modbus response message would also be contained in this field.
The field contents are the same as the original Modbus message, with
two exceptions:
V The Modbus slave address is stripped from the contents. It appears
in the Modbus Plus MAC level destination field.
V The Modbus CRC/LRC error check is stripped from the contents.
Error checking is performed on the entire message in the Modbus
Plus HDLC level CRC16 field.