ABB Relion SMU615 Technical Manual page 224

Section 8
Control functions
218
• Command authority: ensures that the command source is authorized to operate
the object
• Mutual exclusion: ensures that only one command source at a time can control the
object
• Interlocking: allows only safe commands
• Execution: supervises the command execution
• Command canceling: cancels the controlling of a selected object.
In direct operation, a single message is used to initiate the control action of a physical
device. The direct operation method uses less communication network capacity and
bandwidth than the SBO method, because the procedure needs fewer messages for
accurate operation.
The "status-only" mode means that control is not possible (non-controllable) via
communication. However, it is possible to control a disconnector (DCXSWI) from
AU_OPEN and AU_CLOSE inputs.
AU_OPEN and AU_CLOSE control the object directly regardless of
the set Control model. These inputs can be used when control is
wanted to be implemented purely based on ACT logic and no
additional exception handling is needed. However, in case of
simultaneous open and close control, the open control is always
prioritized.
REF 615
Selected
to operate
A070878 V3 EN
Figure 134: Control procedure in the SBO method
REF 615
1. Send reservationto other terminals
2. Receive response
REF 615
1MRS758407 B
REF 615 REF 615
SMU615
Technical Manual