Flexlogic™ Evaluation; Flexlogic™ Procedure Example - GE C60 Instruction Manual

5.4 FLEXLOGIC™
Each equation is evaluated in the order in which the parameters have been entered.
FLEXLOGIC™ PROVIDES LATCHES WHICH BY DEFINITION HAVE A MEMORY ACTION, REMAINING IN
THE SET STATE AFTER THE SET INPUT HAS BEEN ASSERTED. HOWEVER, THEY ARE VOLATILE; I.E.
THEY RESET ON THE RE-APPLICATION OF CONTROL POWER.
CAUTION
WHEN MAKING CHANGES TO PROGRAMMING, ALL FLEXLOGIC™ EQUATIONS ARE RE-COMPILED
WHEN ANY NEW SETTING IS ENTERED, SO ALL LATCHES ARE AUTOMATICALLY RESET. IF IT IS
REQUIRED TO RE-INITIALIZE FLEXLOGIC™ DURING TESTING, FOR EXAMPLE, IT IS SUGGESTED TO
POWER THE UNIT DOWN AND THEN BACK UP.
This section provides an example of implementing logic for a typical application. The sequence of the steps is quite impor-
tant as it should minimize the work necessary to develop the relay settings. Note that the example presented in the figure
below is intended to demonstrate the procedure, not to solve a specific application situation.
In the example below, 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 64) can only be properly assigned once.
VIRTUAL OUTPUT 1
State=ON
VIRTUAL OUTPUT 2
5
State=ON
VIRTUAL INPUT 1
State=ON
DIGITAL ELEMENT 1
State=Pickup
DIGITAL ELEMENT 2
State=Operated
CONTACT INPUT H1c
State=Closed
1. Inspect the example logic diagram to determine if the required logic can be implemented with the FlexLogic™ opera-
tors. If this is not possible, the logic must be altered until this condition is satisfied. Once this is 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 one AND(16), 17 through 25 to another AND(9),
and the outputs from these two gates to a third AND(2).
Inspect each operator between the initial operands and final virtual outputs to determine if the output from the operator
is used as an input to more than one following operator. If so, the operator output must be assigned as a Virtual Output.
For the example shown above, the output of the AND gate is used as an input to both OR#1 and Timer 1, and must
therefore be made a Virtual Output and assigned the next available number (i.e. Virtual Output 3). The final output
must also be assigned to a Virtual Output as Virtual Output 4, which will be programmed in the contact output section
to operate relay H1 (i.e. Output Contact H1).
5-38
Set
LATCH
OR #1 Reset
XOR
Timer 1
Time Delay
AND
on Pickup
(800 ms)
Figure 5–7: EXAMPLE LOGIC SCHEME
C60 Breaker Management Relay
5.4.3 FLEXLOGIC™ EVALUATION
5.4.4 FLEXLOGIC™ PROCEDURE EXAMPLE
Timer 2
Time Delay
OR #2
on Dropout
(200 ms)
5 SETTINGS
Operate Output
Relay H1
827025A2.vsd
GE Multilin