Every RS 485 port on a device has a configuration associated with it and these configuration parameter must be set using the programming software for the particular device.
First thing to consider is device id.Device id can be set with programming software.
The main RS 485 configuration parameters are
1.Baud rate 2.Number of data bits 3.Number of stop bits. 4.Parity
Every single device on the same Rs485 network must all have the exact same settings for their port parameters.it is the only way that the RS 485 network will operate properly.
Baud rate - Stands for bit per second.Serial connection supports following baud rates.
1200bps 2400bps 4800bps 9600bps 19200bps
Baud rate is the rate at which the data is transferred on the RS 485 network.If the device on the same RS 485 network has different baud rate they cant communicate one another.
Number of data bits - Data sent in frames on modbus network. The setting for this is either 7 or 8.This indicates how many bits are present in a frame.
Number of Stop bits - Each RS 485 port when it receives data must know when the data is ended.When the frame is stopped. The setting for this is either 1 or 2.
Parity - Parity is for error checking. Following options are available. None,Even,Odd. Usually None is sufficient.No error checking because that would be used over RS 485 have its own error checking.
Regardless of the manufacture all these setting will be present in the modbus device.