5-106 L30 Line Current Differential System GE Multilin5.5 FLEXLOGIC™ 5 SETTINGS55.5.4 FLEXLOGIC™ EXAMPLEThis 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 figurebelow 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 onlya 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 5–40: EXAMPLE LOGIC SCHEME1. 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 inputsto each gate to verify that the number of inputs does not exceed the FlexLogic™ limits, which is unlikely but possible. Ifthe number of inputs is too high, subdivide the inputs into multiple gates to produce an equivalent. For example, if 25inputs to an AND gate are required, connect Inputs 1 through 16 to AND(16), 17 through 25 to AND(9), and the outputsfrom these two gates to AND(2).Inspect each operator between the initial operands and final virtual outputs to determine if the output from the operatoris 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 musttherefore be made a virtual output and assigned the next available number (i.e. Virtual Output 3). The final output mustalso 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 andvirtual output 4 as shown below.Figure 5–41: LOGIC EXAMPLE WITH VIRTUAL OUTPUTSLATCHCONTACT INPUT H1cState=ClosedXORANDResetSetVIRTUAL OUTPUT 2State=ONVIRTUAL INPUT 1State=ONDIGITAL ELEMENT 1State=PickupDIGITAL ELEMENT 2State=OperatedOR #2 Operate OutputRelay H1OR #1(800 ms)Timer 1Time Delayon Pickup(200 ms)Timer 2Time Delayon DropoutVIRTUAL OUTPUT 1State=ON827025A2.vsdLATCHCONTACT INPUT H1cState=ClosedXORANDResetSetVIRTUAL OUTPUT 2State=ONVIRTUAL INPUT 1State=ONDIGITAL ELEMENT 1State=PickupDIGITAL ELEMENT 2State=OperatedOR #2 VIRTUAL OUTPUT 4OR #1(800 ms)Timer 1Time Delayon Pickup(200 ms)Timer 2Time Delayon DropoutVIRTUAL OUTPUT 1State=ON827026A2.VSDVIRTUAL OUTPUT 3
