GE 850 Instruction Manual page 581

CHAPTER 9: FLEXLOGIC AND OTHER SETPOINTS
FlexLogic
NOTE:
NOTE
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
To provide maximum flexibility, the arrangement of internal digital logic combines fixed
and user-programmed parameters. Logic upon which individual features are designed is
fixed, and all other logic, from digital input signals through elements or combinations of
elements to digital outputs, is variable. The user has complete control of all variable logic
through FlexLogic. In general, the system receives analog and digital inputs, which then
uses FlexLogic to produce analog and digital outputs.
The major sub-systems of a generic 8 Series relay involved in this process are shown as
follows.
For information on the Logic Designer and Logic Monitor menu items, see Help >
User Manual > Logic Designer & Monitor in the EnerVista 8 Series Setup software.
Figure 9-4: FlexLogic Display Hierarchy
The states of all digital signals used in the 850 are represented by flags (FlexLogic™
operands). A digital "1" is represented by a 'set' flag. Any external contact change-of-state
can be used to block an element from operating, as an input to a control feature in a
FLEXLOGIC
9–3