Overview of the Ethernet POWERLINK network and the FEPL-02 module   21
Overview of the Ethernet 
POWERLINK network and the 
FEPL-02 module
What this chapter contains
This chapter contains a short description of the Ethernet 
POWERLINK network and the FEPL-02 Ethernet POWERLINK 
adapter module.
Ethernet POWERLINK network
Ethernet POWERLINK is a communication profile for Real Time 
Ethernet. It extends standard Ethernet IEEE802.3 with a 
mechanism to transfer data deterministically. The mechanism is 
called Slot Communication Network Management (SCNM). SCNM 
is managed by a networked device designated as the Managing 
Node (MN). All other nodes are Controlled Nodes (CN).
Unlike standard Ethernet, SCNM ensures that only one node is 
accessing the network at a time. The schedule is divided into an 
isochronous phase and an asynchronous phase. During the 
isochronous phase, time-critical data is transfered, while the 
asynchronous phase provides bandwidth for the transmission of 
data that is not time-critical. The MN grants access to the physical 
medium via dedicated poll request messages. As a result, only one 
CN has access to the network at a time, and thus no collisions 
occur.