Danfoss MCO 305 Design Manual page 192

MCO 305 Design Guide
32-82 Ramp Type
RAMPTYPE
Option
Linear
S-ramp
Movements with limited jerk
Function
This parameter defines the ramp type: trapeze,
sinusoidal, or limited jerk. These ramp type are
relevant for all movements (POSA, POSR, CVEL,
and MOTOR STOP), but not with SYNCx.
Ramp type 0: trapeze
Ramp type 1: S- ramp
Ramp type 2: limited jerk
default setting
192
__ Parameter Reference __
[0]
[1]
[2]
[ ] value for use in communication via serial communication port
®
MG.33.L4.02 – VLT is a registered Danfoss trademark
Movements with limited jerk start with acceleration
zero and increase acceleration by maximum Jerk
until the maximum acceleration which is defined by
par. 32-81 Shortest Ramp is reached. Then the
movement continues with maximum acceleration.
At the end the acceleration will be decreased by
maximum jerk until acceleration is zero again. The
maximum jerk is calculated by the internal
parameter Jerk Duration JERKMIN.
Function of JERKMIN
JERKMIN defines the minimum time in [ms] re-
quired before reaching the maximum acceleration.
There are four different JERKMIN options, see
"Limited Jerk" in chapter „Functions and
Examples": JERKMIN, JERKMIN2, JERKMIN3,
JERKMIN4.
The maximum Jerk used with par. 32-82 Ramp
Type = 2 is calculated by JERKMIN using following
formulas:
Maximum
Max. Accelerati on
Par. 32
Maximum
Maximum Jerk
Par. Jerk
Note, that par. 32-81 Shortest Ramp and Jerk
Duration are time values in milliseconds.
Calculation sample:
Par. 32-80 VELMAX = 3000 [RPM]
Par. 32-01 ENCODER = 500 counts/rev [PPR]
Par. 32-81 RAMPMIN = 500 ms
Parrameter JERKMIN = 200 ms
This results in:
VELMAX = 3000 * 500 *
= 100 qc/ms
MaxAcc = 200,000 qc/s
MaxJerk = 1,000,000 qc/s
NB!:
A changed setting of Jerk Duration is
executed after the next movement
command (POSA, POSR, CVEL, or MOTOR
STOP) and used for the calculation of the
acceleration. Thus it is possible in NOWAIT ON
mode with a repeated POSA command to adapt
during a movement online (i.e. without stop) the
movement to new definition.
NB!:
If JERKMIN2, JERKMIN3 and/or JERKMIN4
is set to "0" this will default to the same
value as JERKMIN.
Velocity
- 81 Shortest Ramp
Accelerati on
Duration JERKMIN
4
= 100,000 qc/s
60
2 2
= 0.2 qc/ms
3 3
= 0.001 qc/ms