Chapter 4: AC Drive Parameters
Page 4–119
DURApulse GS4 AC Drive User Manual – 1st Ed, Rev A - 10/20/2017
analog inPut ParaMeter exaMPle 7: Positive oFFset with reduced analog gain
This example illustrates how to provide a positive offset of the Analog Input, while using the full
scale of the potentiometer or other analog device. At the same time, the Maximum Frequency
Reference is limited by reducing the Analog Input Gain.
When the analog signal is at its lowest value, the set-point frequency will be at 11.5Hz. When the
analog signal is at its maximum value, the set-point frequency will be 39.6Hz.
•
Minimum Frequency Reference = 11�5Hz
•
Maximum Frequency Reference = 39�6Hz
For AI1, AI2, and AI3: P4.24 (AI V/Hz Calculated Selection) MUST BE SET TO ZERO (All Inputs
Use Bias and Gain) TO ENABLE BIAS AND GAIN CALCULATIONS.
Calculations (see page 4–112 for formulas)
A) Drive Maximum Output Frequency = P0.04 = (1750 rpm / 1750 rpm) x 60Hz = 60Hz
B) Analog Offset % = (11.5Hz / 60Hz) x 100 = 19.2%
Analog Input (AIx) AI1 AI2 AI3
AIx Bias Parameter
P4�10 P4�15 P4�19
C) Analog Gain % = [(39.6Hz – 11.5Hz) / 60Hz] x 100 = 46.8% = AIx Input Gain
Analog Input AI1 AI2 AI3
Polarity
Positive (+) Positive (+) Positive (+) Negative (-)
AIx Gain Parameter
P4�12 P4�17 P4�21 P4�22
D) Mid-point Frequency = [(39.6Hz – 11.5Hz) / 2] + 11.5Hz = 25.6Hz
Parameter Settings
Analog Input AI1 or AI2 or AI3
Parameter Settings
Polarity
Positive (+) Positive (+) Positive (+) Negative (-)
AIx Bias Parameter
P4�10 P4�15 P4�19 19�2%
AIx Polarity Parameter
P4�11 P4�16 P4�20 1: Positive Offset
AIx Gain Parameter
P4�12 P4�17 P4�21 P4�22 46�8%
Reverse Run Parameter
P4�09 0: Digital FWD/REV
Examples Results
•
Output Freq = [ (Analog_In%) x (Gain%) + (Bias%) ] x
Max_Out (Hz)
•
For AI1 set to 0~10V, and an analog input of 5 Volts:
Output Freq = [ (5/10) x (0�468) + (0�192) ] x 60Hz =
25�6Hz
•
For analog input of 10 Volts:
Output Freq = [ (10/10) x (0�468) + (0�192) ] x 60Hz
= 39�6Hz
0V
-10V
0mA
10V
10V
20m
5V
0V
10mA
Maximum
Reference
Output
Positive Offset
0Hz
11.5Hz
25.6Hz
30Hz
39.6Hz
60Hz
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