Tap changer position indication with digital inputs in "binary coded inputs" and "BCD-inputs" mode

Sometimes tap position is done by using multiple digital inputs. There are two methods for doing this: binary coded decimal (BCD) inputs and binary coded inputs. Both support up to five digital inputs but they use a different number format. Whereas binary coded mode 4-bit hexadecimal number is valid up to "F" representing binary 1111 (decimal 15), BCD numbers stop at decimal 9 (1001 in binary). Because of this decimal 10 is 1 0000 in binary. BCD input mode supports up to 18 positions. Image below demonstrates the difference between the two.

BCD input mode or binary coded input mode can be chosen at Control > Control Functions > Voltage regulator > INFO > Tap settings with "Tap position indication" parameter. After choosing either of the modes the inputs are defined at Control > Control Functions > Voltage regulator > IO > Input signal control.

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