Sanken SVCO6, Instruction Manual, Page: 200 / 326

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7-3 Description of Functions
2-1) Setting and modulating method
· Use F2236 (analog input switching) to specify the modulation input.
· Use F1402 or F1404 or F1406 (setting of gain frequency) to set a maximum analog input.
Gain frequency implies the switched frequency (modulated frequency) when a maximum analog input is
specified by F2236, i.e. the switching gain corresponding to modulated frequency of analog input. When
gain frequency is decided, the input analog signal will be switched into modulated frequency. This
frequency is added by the two frequencies (1st & 2nd speed frequency) in disturbed operation to be
modulated as a new frequency.
However, the function codes of 1st speed frequency and 2nd speed frequency will not change directly.
The gain frequency can also be negative. I.e. the switched modulation frequency of analog input
command tends to be negative or is already negative. The negative modulation frequency in disturb
modulation will be calculated by subtraction.
Example 1 Analog input VIF1=0
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10V
Gain frequency F1402=50Hz
Example 2 Analog input VIF1=4
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20 mA
Gain frequency F1402=-30Hz
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Analog input Analog input
2-2) Offset of modulation rate
After adjustment of modulation frequency is finished by analog input, the input modulation frequency is the
two frequencies (1st speed frequency and 2nd speed frequency) in disturbed operation, they are the new
values calculated by addition for modulation.
However, as shown in example 1 and 2, through the polarity of gain frequency (F1402 or F1404 or 1406),
any side set in the addition calculation or subtraction calculation will be modulated.
In this way, when the original frequency (1st speed frequency and 2nd speed frequency) is modulated larger
or smaller, the disturb modulation rate (F2237) can be modulated by setting an offset. The offset is set
according to the proportion of F2237=0
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50%.
The above-mentioned proportion refers to be position of 0Hz (modulation frequency) specified by analog
input. Even though the specified analog modulation input and the gain of modulation frequency through the
0Hz are totally changed, the change scope of modulation frequency is set by the settings in gain frequency
(F1402 or F1404 or F1406).