Sorry I could not attach the application guide for this but site kept erroring on me when I tried to upload. This is the just of it. I have done this before and found it slow compared to Profibus for connection to CU310 or CU320. A null modem cable is what I used.
1. In STARTER, from Project > Set PC/PG interface, select the Serial cable (PPI) interface. If this is not available from the dropdown list, you first have to add it using Select. Note: If the interface cannot be added to the selection menu, the driver for the serial interface has to be installed. The STARTER must not be active when installing the driver.
2. Enter the following settings. The "0" address and the transmission rate of 19.2 kbit/s are important here.
3. On CU310/CU320, set bus address "3" on the Profibus address switch.
4. When setting up the drive unit, also set bus address "3". Note: The bus addresses on CU310/CU320 and on the PC must not be set the same.
5. G150: The connecting cable from CU320 to AOP30 must be ground off on CU320. A null modem cable must be connected up here as a link between the PC (COM interface) and CU320. This interface must not be changed.