GE 845 Instruction Manual page 432

CONTROL
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Figure 4-125: SLD Pushbutton "Block" logic diagram
PB "Bypass" (Hardcoded SLD Pushbutton)
Blocking of the command can be bypassed using the SLD pushbutton "Bypass" (see
4-126:SLD Pushbutton "Bypass Block" logic
applied block is bypassed (see figures: Local Control for breakers/Local Control for
contactor). 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 the
selected breaker or switch, a letter "By" appears next to the symbol in the SLD.
Figure 4-126: SLD Pushbutton "Bypass Block" logic diagram
PB "Tag" (hardcoded SLD pushbutton)
Lockout/Tagout is a practice and procedure to safeguard employees from unexpected
energization or startup of machinery and equipment, or hazardous energy during service
or maintenance activities. If a breakeror disconnect switch is tagged, the open and close
controls 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. The
breaker or switch is tagged by pressing the SLD pushbutton "Tag". If the selected switching
device is tagged, a letter "T" appears under its symbol. Tagging can be achieved in local
mode 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 one
breaker or switch at the time in the single line diagram.
diagram). When pressed, the previously
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
Figure