Chapter 5 Parameters
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VFD-B Series
Revision July 2008, BE16, SW V4.08 & V5.00
5-49
04 - 18
AUI Negative Bias, Reverse Motion Enable/Disable
Factory Setting: 00
Settings
00
No AUI Negative Bias Command
01
Negative Bias: REV Motion Enabled
02
Negative Bias: REV Motion Disabled
In a noisy environment, it is advantageous to use negative bias to provide a noise margin.
Pr.04-00 ~ 04-03, Pr.04-11 ~ 04-18 are used when the source of frequency command is the
analog signal. Refer to the following examples.
Example 1: Standard application
This is the most used setting. The user only needs to set Pr.02-00 to 01, 02 or 03. The frequency
command comes from external potentiometer/current signal on AVI, ACI or AUI.
60Hz
0Hz
0V
4mA
5V
12mA
10V
20mA
Pr.01-00=60Hz--Max. output Freq.
AVI ACI AUI
Pr.04-00 Pr.04-11 Pr.04-15=0%--Bias adjustment
Pr.04-01 Pr.04-12 Pr.04-16=0--Positive bias
Pr.04-02 Pr.04-13 Pr.04-17=100%--Input gain
Pr.04-03 Pr.04-14 Pr.04-18=0No negative bias command
30Hz
Example 2: Use of bias
This example shows the influence of changing the bias. When the input is 0V (4mA) the output
frequency is 10 Hz. At mid-point a potentiometer will give 40 Hz. Once the Maximum Output
Frequency is reached, any further increase of the potentiometer or signal will not increase the output
frequency. (To use the full potentiometer range, please refer to Example 3.) The value of external
input voltage/current 0-8.33V (4-17.33mA) corresponds to the setting frequency 10-60Hz.
60Hz
0Hz 0V
4mA
5V
12mA
10V
20mA
Pr.01-00=60Hz--Max. output Freq.
AVI ACI AUI
Pr.04-00 Pr.04-11 Pr.04-15=16.7%--Bias adjustment
Pr.04-01 Pr.04-12 Pr.04-16=0--Positive bias
Pr.04-02 Pr.04-13 Pr.04-17=100%--Input gain
Pr.04-03 Pr.04-14 Pr.04-18=0--No negative bias command
Gain:100%
Bias adjustment:((10Hz/60Hz)/(Gain/100%))*100%=16.7%
10Hz
Bias
Adjustment
40Hz
