Operating Instructions ACU
15.6.3 Fixed percentages
The four fixed percentages define reference values which are selected via the Fixed Percent
Change-Over 1 75 and Fixed Percent Change-Over 2 76. The Reference Percentage Source 476
defines the addition of the various sources in the reference frequency channel.
By combining the logic states of the fixed percentage change-over modes 1 and 2, fixed percentages
1 through 4 can be selected:
Fixed Percent
Change-Over 1 75
Fixed Percent
Change-Over 2 76
Function / active fixed value
0 = Contact open 1 = Contact closed
15.7 Frequency ramps
The ramps determine how quickly the frequency value is changed if the reference value changes or
after a start, stop or brake command. The maximum admissible ramp gradient can be selected
according to the application and the current consumption of the motor.
If the settings of the frequency ramps are identical for both directions of rotation, the
parameterization via the parameters Acceleration (Clockwise) 420 and Deceleration (Clockwise)
421 is sufficient. The values of the frequency ramps are applied to Acceleration Anticlockwise 422
and Deceleration Anticlockwise 423 if these have been parameterized to the factory setting of -
0.01 Hz/s.
The parameter value of 0.00 Hz/s for the acceleration blocks the corresponding direction of rotation.
Acceleration Anticlockwise
Deceleration Anticlockwise
1)
Value -0.01 Hz/s means that the value of Acceleration (Clockwise) 420 is used.
2)
Value -0.01 Hz/s means that the value of Deceleration (Clockwise) 421 is used.
Setting 0.00 Hz/s will not accelerate nor decelerate the drive due to the limitation of
the ramp.
The ramps for Emergency Stop Clockwise 424 and Emergency Stop Anticlockwise 425 of the drive
to be activated via Operation Mode 630 for the stopping behavior must be selected according to the
application. The non-linear (S-shaped) course of the ramps is not active in the case of an emergency
stop of the drive.