4-29
Gain and bias
If F01 = 3 (the sum of [12] + [C1] is enabled), the bias and gain are independently applied to each of the
voltage and current inputs given to terminals [12] and [C1], and the sum of the two values is applied as the
reference frequency.
In the case of unipolar input (terminal [12] with C35 = 1, terminal [C1], terminal [V2] with C45 = 1)
As shown in the graph above, the relationship between the analog input and the reference frequency specified by
frequency command 1 can arbitrarily be determined by points "A" and "B." Point "A" is defined by the combination
of the bias (F18) and its base point (C50); Point "B," by the combination of the gain (C32, C37 or C42) and its base
point (C34, C39 or C44).
The combination of C32 and C34 applies to terminal [12], that of C37 and C39, to [C1] (C1 function), and that of
C42 and C44, to [C1] (V2 function).
Configure the bias (F18) and gain (C32, C37 or C42), assuming the maximum frequency as 100%, and the bias
base point (C50) and gain base point (C34, C39 or C44), assuming the full scale (10 VDC or 20 mA DC) of analog
input as 100%.
• The analog input less than the bias base point (C50) is limited by the bias value (F18).
• Specifying that the data of the bias base point (C50) is equal to or greater than that of each gain base
point (C34, C39 or C44) will be interpreted as invalid, so the inverter will reset the reference frequency
to 0 Hz.
Example: Setting the bias, gain and their base points when the reference frequency 0 to 60 Hz follows the analog
input of 1 to 5 VDC to terminal [12] (in frequency command 1).
(Point A)
To set the reference frequency to 0 Hz for an analog input being at 1 V, set the bias to 0% (F18 = 0). Since 1 V is
the bias base point and it is equal to 10% of 10 V (full scale of terminal [12]), set the bias base point to 10% (C50 =
10).
(Point B)
To make the maximum frequency equal to the reference frequency for an analog input being at 5 V, set the gain to
100% (C32 = 100). Since 5 V is the gain base point and it is equal to 50% of 10 V (full scale of terminal [12]), set
the gain base point to 50% (C34 = 50).
