ABB FEPL-02 Ethernet POWERLINK, User Manual

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Communication protocol 91
8
Communication protocol
What this chapter contains
This chapter describes the Ethernet POWERLINK communication
protocol for the adapter module.
Ethernet POWERLINK communication cycle
In an Ethernet POWERLINK network, one of the nodes, for
example, a PLC, motion controller or industrial PC, is designated
to function as the Managing Node (MN), the master in the network.
All other devices operate as Controlled Nodes (CN), slaves in the
network. The MN defines the clock pulse for the synchronization of
all devices and manages the data communication cycle. In the
course of one clock cycle within which all nodes are addressed,
the MN sends Poll Requests (PReq) to all CNs one after another.
They reply immediately to the prompts with Poll Responses
(PRes).