Flexlogic Rules; Flexlogic Evaluation; Flexlogic Example - GE c60 Instruction Manual

CHAPTER 5: SETTINGS

5.6.2 FlexLogic rules

When forming a FlexLogic equation, the sequence in the linear array of parameters must follow these general rules:
1. Operands must precede the operator that uses the operands as inputs.
2. Operators have only one output. The output of an operator must be used to create a virtual output if it is to be used as
an input to two or more operators.
3. Assigning the output of an operator to a virtual output terminates the equation.
4. A timer operator (for example, "TIMER 1") or virtual output assignment (for example, " = Virt Op 1") can be used once
only. If this rule is broken, a syntax error is declared.

5.6.3 FlexLogic evaluation

Each equation is evaluated in the order in which the parameters have been entered.
FlexLogic provides latches that by definition have a memory action, remaining in the set state after the set
input has been asserted. However, they are volatile; that is, they reset on the re-application of control power.
NOTE
When making changes to settings, all FlexLogic equations are re-compiled whenever any new setting value is
entered, so that all latches are reset automatically. If it is necessary to re-initialize FlexLogic during testing, for
example, power down the unit and then back up.

5.6.4 FlexLogic example

This section provides an example of logic implementation for a typical application. The sequence of steps is important to
minimize the work to develop the relay settings. Note that the example in the following figure demonstrates the procedure,
not to solve a specific application situation.
In the example, it is assumed that logic has already been programmed to produce virtual outputs 1 and 2, and is only a
part of the full set of equations used. When using FlexLogic, it is important to make a note of each virtual output used; a
virtual output designation (1 to 96) can be assigned only once.
1. Inspect the example logic diagram to determine if the required logic can be implemented with the FlexLogic
operators. If this is not possible, the logic must be altered until this condition is satisfied. Once done, count the inputs
to each gate to verify that the number of inputs does not exceed the FlexLogic limits, which is unlikely but possible. If
the number of inputs is too high, subdivide the inputs into multiple gates to produce an equivalent. For example, if 25
inputs to an AND gate are required, connect Inputs 1 through 16 to AND(16), 17 through 25 to AND(9), and the outputs
from these two gates to AND(2).
C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 5-77: Logic example
FLEXLOGIC
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