There are no clean methods to analyze master and slave Modbus messages on
an RS-485 bus.
Currently, the following Modbus analyzers are supported:
RTU - Master
RTU - Slave
ASCII - Master
ASCII - Slave
When an RS-485 line is probed with Logic, master and slave devices are transmitting the requests and responses on the same bus, and the currently provided analyzers do not have the capability to parse both master and slave messages.
If the "RTU - Master" analyzer is selected, the requests from the master are parsed correctly, but the responses from slave are not, and are often interpreted as faults, and vice-versa happens when "RTU Slave" analyzer is selected.