About SERCOS® Phases Standard

Standard IEC 1491

The IEC 1491 Standard (the SERCOS®-based international servo drive communications protocol standard) defines the following five phases of communicating with a SERCOS® drive.

SERCOS® phases

The following table defines the phases:

Phase	Meaning
0	The loop is not communicating.
1	The controller is finding the drives which are on the loop.
2	The SERCOS® loop timing parameters are exchanged with the drives.
3	The service channels to the drives are functioning and all timing parameters are being used. The GetIDN and SetIDN functions are ready for operation.
4	The motion controller is sending cyclic communication information to the drives. The loop is up and motion commands are allowed.