GE 745 TRANSFORMER MANAGEMENT RELAY, Instruction Manual

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5-82 745 Transformer Management Relay GE Power Management
5.7 S5 OUTPUTS 5 SETPOINTS
5
5.7.3 FLEXLOGIC™ RULES
1. INPUTS TO A GATE ALWAYS PRECEDE THE GATE IN THE EQUATION.
2. GATES HAVE ONLY ONE OUTPUT.
3. THE OUTPUT OF A GATE CAN BE THE INPUT TO ANOTHER GATE. Therefore, according to rule 1, the
former gate will precede the latter gate in the equation.)
4. ANY INPUT CAN BE USED MORE THAN ONCE IN AN EQUATION.
5. THE OUTPUT OF AN EQUATION CAN BE USED AS AN INPUT TO ANY EQUATION (INCLUDING
FEEDBACK TO ITSELF).
6. IF ALL PARAMETERS OF AN EQUATION ARE NOT USED, THE ‘END’ PARAMETER MUST FOLLOW
THE LAST PARAMETER USED.
As an example, assume that the following logic is required to operate Output Relay 2:
Figure 5–14: FLEXLOGIC™ EXAMPLE
Based on the rules given above, the Output Relay 2 FlexLogic™ equation is shown above. On the left is a
stack of boxes showing the FlexLogic™ messages for Output Relay 2. On the right of the stack of boxes is an
illustration of how the equation is interpreted.
In this example, the inputs of the 4-input OR gate are
Percent Diff OP
,
Inst Diff OP
, the output of the XOR gate, and
the output of the AND gate. The inputs of the 2-input AND gate are the output of the NOT gate, and
Output Relay
2
. The input to the NOT gate is
Logic Input 2
. The inputs to the 2-input XOR gate are
Virtual Output 1
and
Logic Input
1
. For all these gates, the inputs precede the gate itself.
This ordering of parameters of an equation, where the gate (or “operator”) follows the input (or “value”) is com-
monly referred to as “Postfix” or “Reverse Polish” notation.
Percent Diff
OPERATE
Inst Diff
OPERATE
Virtual Output 1
OPERATE
AND
XOR
Logic Input 2
ASSERTED
Logic Input 1
ASSERTED
OR
Output Relay 2
OPERATE