Different stop bit settings for different Modbus slaves on the same bus

Issue

Is it possible to have different stop bit settings in different Modbus slaves on the same bus?

Product Line

SmartStruxure Solution

Environment

Modbus serial communication

Cause

In StruxureWare Building Operation Workstation there is an "Auto" setting for the Master and Slave "Stop Bit" setting. This could be interpreted as "automatically" detecting the slave or master's stop bit setting.

Resolution

The "Auto" setting is only to detect how many stop bits are required in certain circumstances such as when parity setting is set to none, 2 stop bits must be used. The settings are the master's settings for the entire bus, so all the slaves have to be set to match the Master.