Connection timeout when setting new baud rate using modbus_write_register

[emc2tmax]

The default baud rate for the Wellpro modbus units I have is 9600 baud and the units work fine with libmodbus 3.0.6 and 3.1.2.

I can set a new module address using modbus_write_register( ctx, 0x0064, <new_addr> ), this works correctly.

But I cannot set a new baud rate using modbus_write_register( ctx, 0x0065, modBaud ), where modBaud =1 for 4800, =2 for 9600 and =3 for 19200.  I always get a "Connection timed out" error regardless of what baud rate I try to set.  The unit remains working on 9600 baud.

Does anyone know why I am getting this error.

Thanks
Dave.