Danfoss VLT5000 SyncPos Operating Instructions Manual page 179

12 KDER (703)
The Derivative factor Derivative factor Derivative factor Derivative factor Derivative factor KDER is the correction factor
with which the changing speed of a motor position
error is evaluated.
The derivative factor works against the tendency to
overswing due to a high proportional share and
'dampens' the system. However, if the derivative
factor selected is too large this will lead to a
'nervous' drive.
Content
Derivative value for PID control
Parameter Group
Axis parameter PID-Controller AXR
CAM-Editor: index card PID
Value range
0 ... 65000
13 KINT (704)
The Inte Inte Inte Integral Factor Inte gral Factor gral Factor gral Factor KINT is the weighting factor, with gral Factor
which at time n the sum of all motor position errors
are evaluated.
The integral factor of the PID filter causes a corre-
sponding corrective motor torque which increases
over time. Through the integral share a static posi-
tion error is reduced to zero, even if a constant load
is affecting the motor.
However, an integral factor which is too large leads
to a 'nervous' drive.
Content
Integral value for PID control
Parameter Group
Axis parameter PID-Controller AXR
CAM-Editor: index card PID
Value range
0 ... 65000
178
Programmable SyncPos motion controller
14 TI M E R
The TIMER parameter determines the sampling time
of the control algorithm.
For example, increase the value of the factory
settings
• for very low pulse frequency, such as from 1 to
2 qc per sampling time. You need at least 10 to
20 qc per sampling time.
• Or for very slow systems with a long dead time.
If 1 ms is used here for control, large motors
will vibrate.
Content
Sampling time for PID control
Parameter Group
Axis parameter PID-Controller AXR
CAM-Editor: index card PID
★ 0
Unit
msec
Value range
1... MLONG
Accordingly, the value should not be set
higher than 1000 (= 1 s). This would be
a very slow control.
NB!
Note that is has a direct effect on the PID
loop e.g. if you double the TIMER the KPROP
(11) has twice the effect.
★ 0
MG. 1 0.J8.02 – VLT is a registered Danfoss trade mark
★ 1