User Manual
Chapter 4
GFK-2849A
Oct 2019
System Operation
100
Figure 84
SAU
–
Synchronized Active Unit
SBU
–
Synchronized Backup Unit
•
Both ECM850s maintain IEC 61850 connections to the IED (IEC 61850 Server
device). Only the ECM850 on the SAU, however, produces outputs on wire. The
ECM850 on the SBU unit has a connection with the IED but does not send any write
requests to the IED on wire.
•
Protocol Input and Output Variables are configured in the Transfer list of the CRU.
•
Both Primary and Secondary ECM850s reads Input data from the IED. However, the
SBU’s Input data is overwritten by the SAU input data via Tra
nsfer list
synchronization.
•
The SAU drives Output data to the IED. The Output Data on the SBU is overwritten
by the SAU’s output data via Transfer list synchronization. The ECM850 on the
SBU,
however, will not write this synchronized Output data to the IED on wire.
4.8.3
Enabling or Disabling Protocol Outputs
A SVC REQ block is provided for enabling or disabling Protocol Outputs. This is described in
section 4.6.1 SVC REQ for Enabling or Disabling Protocol Outputs.
4.8.4
Status Reporting for Protocol Outputs State
The ECM850 Protocol Outputs state can be determined from Bit 10 (Outputs Disabled) of
the Status information.
