Fieldbus Section 1  Overview
16 M&I – AC 900F Controller
 
Telecontrol protocol
The function blocks of the telecontrol library are designed for the connection 
between the Freelance Engineering tool and external systems. The link is made via 
the serial interface (RS-232) or the Ethernet interface of the CPU module. The 
telecontrol protocol complying to IEC 60870-5-101 (serial)/IEC 60870-5-104 
(TCP/Ethernet) is used.
For the serial interface, the telecontrol protocol provides device modules for 
symmetrical data transmission (FWK_DEV), asymmetrical data transmission as a 
master (FWK_DEV_M) and asymmetrical data transmission as a slave 
(FWK_DEV_SL). These modules are configured in the hardware structure. Please 
refer to the Engineering Manual, System Configuration, Hardware Structure for 
more detailed information.
For Ethernet-supported communication, the Ethernet interface and the parameters of 
the IEC 60870-5-104 compliant protocol must be set in the FWK_DEV_104 
function block designed for telecontrol connection in the Ethernet network. The 
FWK_DEV_104 device module can be configured in the hardware structure below 
the Ethernet interface of the AC 900F.
ABB CAN Bus protocol
The CAN Bus of the AC 900F controller is intended to be used for connecting rack-
based Freelance I/O modules only. With this feature, the current AC 900F controller 
CPU modules of type PM 902F/901F can alternatively take over the tasks of the 
CPU module types DCP 02/10 of the Freelance rack system.