G 3800 X036 Operation Manual
August 2006
90
© 2006 Carlo Gavazzi Industri A/S. All rights reserved
This system topology ensures a safe system operation, because in case of a short circuit or interruption of the
RS485 network between Mastergenerators, the control functions on each Dupline network will continue to
operate, but of course only based on the local signals. Also, if one of the Dupline networks is short circuited or
interrupted, the other Dupline networks will continue to operate.
In these systems, it is common to have a PC with SCADA software for monitoring the entire system and for
changing control parameters like temperature set-points and switching times. In large Dupline systems, this is
achieved by connecting the COM-port of the PC to one of the RS232 ports of the Mastergenerator operating
as RS485 master. This enables the PC to read and control data in all the Dupline networks, and to read or write
a configuration file to any Mastergenerator using the Modbus protocol.
It is also possible to use a PLC or PC as master in the RS485 network. In this case there is no automatic data
exchange between the Dupline networks, but the reaction time on the RS485 network is slightly faster.
For RS485 installation guidelines, please refer to Appendix B of this manual.
4.6. Setup of Communication Ports
