Description of the Software Modules and Parameters
Parameter manual b maXX BM3000
Document no.: 5.12001.07
399
of 820
4
4.6 Set Value Generators
4.6.1 Ramp function generator
The ramp function generator is used to generate rising or falling ramps in the Speed Pre-
set 1 (Z109.1– = 2) and Speed Control (Z109.1– = -3) speed-controlled operating
modes. Additionally, it is used for controlling braking procedures (Quick Stop, Drive Shut-
down, Inhibit Drive).
The ramp function generator has an input with separately adjustable ramp-up and ramp-
down times. Furthermore the ramp-down time for the Quick Stop function is separately
adjustable.
The input and output values for the ramp function generator are relative quantities
(±100
%) and are referred to the Maximum drive speed parameter (Z110.13–).
The ramp slope for the acceleration and braking procedures is defined by the ramp-up
and ramp-down times. The times correspond to a 100
% change in the set value.
For additional rounding of the ramp-up or ramp-down ramps, a PT
1
element (smoothing)
with adjustable time constant is connected after the ramp function generator.
The ramp function generator provides the following control options via the control word
(
Z108.1–):
m Inhibit ramp generator (set output permanently to 0, ramp-down at the current limit)
m Stop ramp generator (freeze output value)
m Inhibit ramp generator set value (set input internally to 0, ramp-down on the ramp-down
ramp)
The following options can additionally be selected via Ramp Generator Mode Z110.2–:
m Selection between a 16-bit parameter (Z110.5–) or a 32-bit parameter (Z110.4–) as
input value for the ramp function generator.
m Blocking of positive or negative set values.
m Reversal of set value sign. The internal processing sequence is inhibit before sign re-
versal.
m Switch-off of speed set value synchronization when activating the ramp function gen-
erator.
m Adjustment of ramp shape:
n Trapezoidal speed profile; stepped acceleration.
There is a possibility of smoothing the speed by means of a PT
1
element.
n S-Curve with quadratic speed profile; trapezoidal acceleration.
m Task selection to process the set values:
The set values of the ramp function generator can either be calculated in the RT1 task
(1 ms; default) or in the fieldbus task. The setting is made by bit 16 of the
Z110.2–
mode.
m Speed profile in zero-crossing at change of direction with or without rounding-off.
m The set quick stop time Z110.8– applies to
n change of set value from 100% to 0%
n change of set value from actual set value at ramp function generator output Z110.3–
to 0%. This causes a constant braking time from all speeds at ramp function gener-
ator output.
m The set SS1 stop time Z110.21– applies to