Application note
Integrated Modbus support
AN00198
ABB Motion control products
6
new.abb.com/motion
When using Modbus the byte and word order of the Modbus data is important. It is possible to change the settings for both byte
and word order for Client and Server operation in the drives. The default byte and word orders are configured to match the
requirements for communication with other ABB Motion, PLC and HMI products. Some third party Modbus products tend to use
little endian word order so when using a third party Client it may be necessary to adjust this setting in the drive.
Modbus RTU and TCP are also supported as standard on the CP600 and CP600-eco ranges of HMI panels as well as the
AC500 PLC range.
Network topology
Modbus RTU
When using 2-wire RS485 be sure to include 120 ohm terminating resistors between data lines A and B at each end of the
network to avoid data corruption.
When using 4-wire RS422 be sure to include 120 ohm terminating resistors between RX+ and RX- at each end of the network to
avoid data corruption.
