YASKAWA SI-T/ V7, Technical Manual, Page: 58 / 157

5-6
A. n083 : Prohibited Frequency 1 Factory setting (each): 0.00
n084 : Prohibited Frequency 2
Range (each): 0.00 to 400.0 Hz
n085 : Prohibited Frequency 3
These parameters allow programming of up to three prohibited frequency points for eliminating
problems with resonant vibration of the motor/machine. This feature does not actually eliminate the
selected frequency values, but will accelerate and decelerate the motor through the prohibited
bandwidth.
B. n086 : Prohibited Frequency Deadband Factory setting: 0.00
Range: 0.00 to 25.50 Hz
This parameter determines the width of the deadband around each selected prohibited frequency
point.
EXAMPLE:
Vibration encountered between 30.00 and 36.00 Hz.
SOLUTION: Set n083 to " 33.00 ". This is the center of the problem
frequency band.
Set n086 to " 3.00 ". This will cause the Drive to reject all
frequency command values between 30.00 and 36.00 Hz.
A frequency command in the deadband will be converted to the bottom
value of the deadband, e.g. a command of 33.00 Hz would result in a run
frequency of 30.00 Hz.
NOTE: n083 > n084 > n085 - The highest prohibit frequency required needs to be in n083.
The next highest prohibit frequency needs to be in n084, and the lowest prohibit frequency
needs to be in n085.
FREQ. CMD
36.00 Hz
n083 = 33.00 Hz
30.00 Hz
0
Total Deadband = 6.00 Hz
± n086 (3.00 Hz)
OUTPUT FREQUENCY (Hz)
5.6 CRITICAL FREQUENCY REJECTION