Quantizing may be used when the noise level is high in the analog
input signal. The inverter output frequency changes in consistant
intervals (steps) based on measuring (quantizing) the height (value) of
the analog input signal. Delicate control (resolution) of the output
frequency is not as good compared to standard resolution of 0.1%.
Parameter values for quantizing refer to a percentage based on the
maximum input. Therefore, when In.17 is set to 1% of the analog
maximum input of 10 V and with a maximum frequency of 60 Hz, the
output frequency will increase or decrease by 0.6 Hz per 0.1V difference.
With quantizing applied, changes to the inverter output frequency for
analog signal increase and analog signal decrease are treated
differently. When the input signal increases, the output frequency starts
increasing when the height becomes equivalent to 3/4 of the quantizing
value. From then on, the output frequency increases according to the
quantizing value. When the input signal decreases, the output
frequency starts decreasing when the height becomes equivalent to 1/4
of the quantizing value.
Although the noise can be reduced using the low-pass filter (In.07), the
inverter output response to the input signal takes longer with higher
filter times. It can become difficult to control the output frequency when
the input signal is delayed, a period of long pulse (ripple) may occur on
the output frequency.
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