ABB RET650 Technical Manual page 274

Section 12
Control
268
in three steps, the selection, command evaluation and the supervision of position.
Each step ends up with a pulsed signal to indicate that the respective step in the
command sequence is finished. If an error occurs in one of the steps in the command
sequence, the sequence is terminated and the error is mapped into the enumerated
variable "cause" attribute belonging to the pulsed response signal for the IEC 61850
communication. The last cause L_CAUSE can be read from the function block and
used for example at commissioning.
There is no relation between the command direction and the actual
position. For example, if the switch is in close position it is possible to
execute a close command.
Before an execution command, an evaluation of the position is done. If the parameter
PosDependent is true and the position is in intermediate state or in bad state no
execution command is sent. If the parameter is false the execution command is sent
independent of the position value.
Evaluation of position
The position output from switch (SXCBR or SXSWI) is connected to SCSWI. With
the group signal connection the SCSWI obtains the position, time stamps and quality
attributes of the position which is used for further evaluation.
In the supervision phase, the switch controller function evaluates the "cause" values
from the switch modules Circuit breaker (SXCBR)/ Circuit switch (SXSWI). At error
the "cause" value with highest priority is shown.
Blocking principles
The blocking signals are normally coming from the bay control function (QCBAY)
and via the IEC 61850 communication from the operator place.
The IEC 61850 communication has always priority over binary
inputs, e.g. a block command on binary inputs will not prevent
commands over IEC 61850.
The different blocking possibilities are:
• Block/deblock of command. It is used to block command for operation of
position.
• Blocking of function, BLOCK, signal from DO (Data Object) Behavior (IEC
61850). If DO Behavior is set to "blocked" it means that the function is active, but
no outputs are generated, no reporting, control commands are rejected and
functional and configuration data is visible.
The different block conditions will only affect the operation of this
function, that is, no blocking signals will be "forwarded" to other
functions. The above blocking outputs are stored in a non-volatile
memory.
1MRK 504 135-UEN A
Technical manual