12.2.8.4 SettingsThe function does not have any parameters available in Local HMI or Protection andControl IED Manager (PCM600).12.2.9 Operation principle12.2.9.1 Switch controller SCSWIThe Switch controller (SCSWI) is provided with verification checks for the select -execute sequence, that is, checks the conditions prior each step of the operation. Theinvolved functions for these condition verifications are interlocking, reservation,blockings and synchronism-check.Control handling.Two types of control models can be used. The two control models are "direct with normalsecurity" and "SBO (Select-Before-Operate) with enhanced security". The parameterCtlModel defines which one of the two control models is used. The control model "directwith normal security" does not require a select whereas, the "SBO with enhanced security"command model requires a select before execution.Normal security means that only the command is evaluated and the resulting position isnot supervised. Enhanced security means that the command sequence is supervised inthree steps, the selection, command evaluation and the supervision of position. Each stepends up with a pulsed signal to indicate that the respective step in the command sequenceis finished. If an error occurs in one of the steps in the command sequence, the sequenceis terminated and the error is mapped into the enumerated variable "cause" attributebelonging to the pulsed response signal for the IEC 61850 communication. The last causeL_CAUSE can be read from the function block and used for example at commissioning.There is no relation between the command direction and the actualposition. For example, if the switch is in close position it is possible toexecute a close command.Before an execution command, an evaluation of the position is done. If the parameterPosDependent is true and the position is in intermediate state or in bad state no executioncommand is sent. If the parameter is false the execution command is sent independent ofthe position value.Evaluation of positionThe position output from switch (SXCBR or SXSWI) is connected to SCSWI. With thegroup signal connection the SCSWI obtains the position, time stamps and qualityattributes of the position which is used for further evaluation.1MRK 502 048-UUS A Section 12Control373Technical manual
