ABB REC670 Applications Manual page 592

Section 23
Basic IED functions
586
measurement functions (CVMMXN, CMMXU,VMMXU, etc.)
which shall be fed by preprocessing blocks with cycle 8.
When two or more preprocessing blocks are used to feed one
protection function (e.g. over-power function GOPPDOP), it is of
outmost importance that parameter setting DFTReference has the
same set value for all of the preprocessing blocks involved
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