Parameter
02.006
S Ramp Enable
Short description
Set to 1 to enable the use of S ramps
Mode
Open
‑
loop
Minimum
0
Maximum
1
Default
0
Units
Type
1 Bit User Save
Update Rate
16ms
Display Format
Standard
Decimal Places
0
Coding
RW
If
S Ramp Enable
(02.006) = 0 linear ramps are used, but if
S Ramp Enable
(02.006) = 1 a limit is applied to the rate of change of acceleration to give S
ramps. The S ramp function is disabled during deceleration when the standard ramp voltage controller is active. When the motor is accelerated again
the acceleration rate used by the S ramp function is reset to zero and has to rise to the programmed acceleration level at the programmed rate of
change (see
Max Rate Of Change Of Acceleration
(02.007) and
S Ramp Set-up Mode
(02.041) ).
Parameter
02.007
Max Rate Of Change Of Acceleration
Short description
Defines the maximum rate of change of acceleration used by the ramp system
Mode
Open
‑
loop
Minimum
0.0
Maximum
300.0
Default
3.1
Units
s²/100Hz
Type
32 Bit User Save
Update Rate
Background read
Display Format
Standard
Decimal Places
1
Coding
RW
A rate of change of acceleration can be applied such that the acceleration rate changes linearly between 0 and the value
in
Max Rate Of Change Of Acceleration
(02.007) during acceleration, and between
Max Rate Of Change Of Acceleration
(02.007) and 0 during
deceleration. If
S Ramp Set-up Mode
(02.041) = 0 then the maximum rate of change of acceleration in both directions, accelerating away from or
towards zero, is defined by
Max Rate Of Change Of Acceleration
(02.007).
The general equations are given below for a linear ramp and S ramp where
Δw is the required change of frequency or speed
a
Max
is the maximum allowed acceleration in units of frequency/s or speed/s
J
Max
is the maximum rate of change of acceleration (i.e. jerk) in units of frequency/s
2
or speed/s
2
The time for a linear ramp to give a change of frequency or speed Δw is
T
Linear
= Δw / a
Max
If an S ramp is used w
B
is the change of frequency or speed as the acceleration changes from zero to aMax, i.e. the S shaped part of the frequency or
speed change.
w
B
= a
Max
2
/ 2J
Max
If the required frequency or speed change is less than 2wB, i.e. Δw < 2wB, then the acceleration never reaches its limit and the ramp does not contain a
linear ramp section and the time for the ramp is given by
T
SRamp1
= 2 √(Δw / J
Max
)
Otherwise
T
SRamp2
= (Δw / a
Max
) + (a
Max
/ J
Max
)
The following is an example based on the default parameter values for Open-loop mode. The diagram below shows a change of frequency from 0Hz to
50Hz with the ramp rate set to 5.0s/100Hz and
Max Rate Of Change Of Acceleration
(02.007) set to its default value of 3.1s
2
/100Hz.
Unidrive M200 Parameter Reference Guide
Issue: 01.05.00.10
33
Summary of Contents for unidrive m200
Page 1: ...Parameter Reference Guide Unidrive M200 Open loop Mode Issue 01 05 00 10 ...
Page 30: ...30 Unidrive M200 Parameter Reference Guide Issue 01 05 00 10 ...
Page 83: ...Enable logic Unidrive M200 Parameter Reference Guide Issue 01 05 00 10 83 ...
Page 125: ...Unidrive M200 Parameter Reference Guide Issue 01 05 00 10 125 ...
Page 145: ...Unidrive M200 Parameter Reference Guide Issue 01 05 00 10 145 ...
Page 204: ...204 Unidrive M200 Parameter Reference Guide Issue 01 05 00 10 ...