GE UR Series C70, Instruction Manual

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GE Multilin C70 Capacitor Bank Protection and Control System 5-95
5 SETTINGS 5.5 FLEXLOGIC™
5
5.5.4 FLEXLOGIC™ EXAMPLE
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 96) can only be properly assigned once.
Figure 5–35: EXAMPLE LOGIC SCHEME
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 AND(16), 17 through 25 to AND(9), and the outputs
from these two gates to 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 oper-
ate relay H1 (that is, contact output H1).
Therefore, the required logic can be implemented with two FlexLogic™ equations with outputs of virtual output 3 and
virtual output 4 as shown below.
Figure 5–36: LOGIC EXAMPLE WITH VIRTUAL OUTPUTS
LATCH
CONTACT INPUT H1c
State=Closed
XOR
AND
Reset
Set
VIRTUAL OUTPUT 2
State=ON
VIRTUAL INPUT 1
State=ON
DIGITAL ELEMENT 1
State=Pickup
DIGITAL ELEMENT 2
State=Operated
OR #2
Operate Output
Relay H1
OR #1
(800 ms)
Timer 1
Time Delay
on Pickup
(200 ms)
Timer 2
Time Delay
on Dropout
VIRTUAL OUTPUT 1
State=ON
827025A2.vsd
LATCH
CONTACT INPUT H1c
State=Closed
XOR
AND
Reset
Set
VIRTUAL OUTPUT 2
State=ON
VIRTUAL INPUT 1
State=ON
DIGITAL ELEMENT 1
State=Pickup
DIGITAL ELEMENT 2
State=Operated
OR #2 VIRTUAL OUTPUT 4
OR #1
(800 ms)
Timer 1
Time Delay
on Pickup
(200 ms)
Timer 2
Time Delay
on Dropout
VIRTUAL OUTPUT 1
State=ON
827026A2.VSD
VIRTUAL OUTPUT 3