12.4.2 Application SEMOD114927-4 v7The logic rotating switch for function selection and LHMI presentation function(SLGAPC) (or the selector switch function block, as it is also known) is used to geta selector switch functionality similar with the one provided by a hardware multi-position selector switch. Hardware selector switches are used extensively byutilities, in order to have different functions operating on pre-set values. Hardwareswitches are however sources for maintenance issues, lower system reliability andextended purchase portfolio. The virtual selector switches eliminate all theseproblems.SLGAPC function block has two operating inputs (UP and DOWN), one blockinginput (BLOCK) and one operator position input (PSTO).SLGAPC can be activated both from the local HMI and from external sources(switches) via the IED binary inputs. It also allows the operation from remote (likethe station computer). SWPOSN is an integer value output, giving the actual outputnumber. Since the number of positions of the switch can be established by settings(see below), one must be careful in coordinating the settings with the configuration(if one sets the number of positions to x in settings – for example, there will beonly the first x outputs available from the block in the configuration). Also thefrequency of the (UP or DOWN) pulses should be lower than the setting tPulse.From the local HMI, the selector switch can be operated from Single-line diagram(SLD).12.4.3 Setting guidelines SEMOD115063-294 v7The following settings are available for the Logic rotating switch for functionselection and LHMI presentation (SLGAPC) function:Operation: Sets the operation of the function On or Off.NrPos: Sets the number of positions in the switch (max. 32).OutType: Steady or Pulsed.tPulse: In case of a pulsed output, it gives the length of the pulse (in seconds).tDelay: The delay between the UP or DOWN activation signal positive front andthe output activation.StopAtExtremes: Sets the behavior of the switch at the end positions – if set toDisabled, when pressing UP while on first position, the switch will jump to the lastposition; when pressing DOWN at the last position, the switch will jump to the firstposition; when set to Enabled, no jump will be allowed.Section 12 1MRK 505 393-UEN BControl268 Line differential protection RED650 2.2 IECApplication manual
