CHAPTER 4: SETPOINTS CONTROL889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–343Figure 4-143: SLD Pushbutton “Block” logic diagramPB “Bypass” (Hardcoded SLD Pushbutton)Blocking of the command can be bypassed using the SLD pushbutton “Bypass” (see Figure4-144:SLD Pushbutton “Bypass Block” logic diagram). When pressed, the previouslyapplied block is bypassed (see figures: Local Control for breakers/Local Control forcontactor). For example if the block was applied when the Breaker/Switch was opened,pressing the PB “Bypass” will allow closing command. If the bypass is active for theselected breaker or switch, a letter “By” appears next to the symbol in the SLD.Figure 4-144: SLD Pushbutton “Bypass Block” logic diagramPB “Tag” (hardcoded SLD pushbutton)Lockout/Tagout is a practice and procedure to safeguard employees from unexpectedenergization or startup of machinery and equipment, or hazardous energy during serviceor maintenance activities. If a breakeror disconnect switch is tagged, the open and closecontrols are inhibited.Both remote and local control commands are blocked if the tagged operand BKR# Tag ON,or SW# Tag ON is active for the selected particular breaker or switch respectively. Thebreaker or switch is tagged by pressing the SLD pushbutton “Tag”. If the selected switchingdevice is tagged, a letter “T” appears under its symbol. Tagging can be achieved in localmode using the front panel control from the configurable SLD screens. The Pushbutton“Tag” logic diagram shows the tagging logic diagram for a switch. The logic applies to onebreaker or switch at the time in the single line diagram.894197A1.cdrFLEXLOGIC OPERANDBKR [X] SelectedSW [X] SelectedANDSLatchRNon-Volatile LatchReset-Dominantpositiveone shotBlockPB “BLOCK”ANDFLEXLOGIC OPERANDBlock ONFLEXLOGIC OPERANDBlock OFFORFLEXLOGIC OPERANDSBO Enabled894198A1.cdrFLEXLOGIC OPERANDBKR [X] SelectedSW [X] SelectedANDSLatchRNon-Volatile LatchReset - Dominantpositiveone shotByp BlkPB “BYPASSBLOCK”ANDFLEXLOGIC OPERANDBypass Block ONFLEXLOGIC OPERANDBypass Block OFFORFLEXLOGIC OPERANDSBO Enabled
