On a RS485 network there can only be one master at any one time. If you connect both a FP4030MR (which works as a master) and a I-7017, you are programming the Nano-10 to be the master. This interferes with the FP4030MR attempts to talk to the Nano-10 as a slave. That causes communication problem.
If you want to use both FP4030MR and I-7017 at the same time you will need to use two separate comm ports. You can upgrade to a FMD88-10 and connect FP4030MR to the RS232 port and the I-7017 to the RS485 port.