39
Character Timeout
values
Message Timeout
values
Serial TX delay after RX
values
whether to
Swap 4x/0H to get 3x/1x
register conversions
Advanced Modbus Protocol Settings Menu
SLAVE ADDRESS / UNIT ID SOURCE
All devices connected to a TCP/IP network require a unique IP address. Each
MES1A/B Converter has a unique IP address on the network, allowing messages to
be directed to it. However, when multiple Modbus/RTU devices are connected to the
RS-485 bus of an MES1B there must be a way to address them individually.
Standard Modbus/RTU fields are encapsulated inside Modbus/TCP messages.
Modbus/RTU’s Slave Address field is called the Unit ID in Modbus/TCP. The Unit ID is
used to specify a particular Modbus/RTU device on the serial side of the MES1A/B.
When the MES1A/B receives a message (sent to its IP address), it looks at the Unit ID
field of the message and passes the message to the specified slave.
0 FOR AUTO
Setting the
Slave Address
field to 0 allows the MES1A/B to use the Unit ID received
from a Modbus master to direct messages to a specific slave address. The MES1A/B
receives the Unit ID number on the Modbus/TCP side and passes it along as the Slave
Address on the serial side of the converter.
