ABB RED615 Technical Manual page 676

Section 9
Control functions
670
When the apparatus already is in the right position, the maximum pulse length is
given.
The Pulse length setting does not affect the length of the trip pulse.
Control methods
The command execution mode can be set with the Control model setting. The
alternatives for command execution are direct control and secured object control,
which can be used to secure controlling.
The secured object control SBO is an important feature of the communication
protocols that support horizontal communication, because the command
reservation and interlocking signals can be transferred with a bus. All secured
control operations require two-step commands: a selection step and an execution
step. The secured object control is responsible for the several tasks.
• 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.
1YHT530004D05 D
615 series
Technical Manual