Chapter 16 PLC Function ApplicationsC2000 Plus 
16-154
16-10  Internal communications main node control
The protocol has been developed in order to facilitate the use of RS-485 instead of CANopen in certain
application situations. The RS-485 protocol offers similar real-time characteristics as CANopen. The
maximum number of slave devices is 8.
Internal communications have a master-slave structure. The initiation method is very simple:
Slave device:
Set Pr. 09-31 = -1 to -8 in order to access 8 nodes, and set Pr. 00-20 = 1 to define the control source
as RS-485 and access the reference sources that must be controlled, namely speed command (Pr.
00-21 = 2), torque command (Pr. 11-33 = 1), and position command (Pr. 11-40=2). This will complete
slave device settings. (PLC functions do not need
 to be activated)
System 
Setting the master is even simpler; it is only necessary to set Pr. 09-31 = -10, and enable the PLC. 
Hardware wiring: The master and slave stations are connected via the RS-485 serial port. The C2000 
Plus provides two types of RS-485 serial port interfaces, see the figure below: (please refer to Chapter 
06 “Control Terminals” concerning detailed terminal connections)