Siemens SINUMERIK 840Di Function Manual page 437

New setting rule for MD32810 and MD32800
If the new filter is active, the setting rule for machine data:
MD32810 $MA_EQUIV_SPEEDCTRL_TIME
and
MD32800 $MA_EQUIV_CURRCTRL_TIME are modified.
This means that, if the old balancing filter had previously been active and is to be changed to
the new filter, the following actions must be considered:
Setting the equivalent time constant with speed feedforward control
If the previous setting was MD32620 $MA_FFW_MODE = 1:
1. Set MD32620 $MA_FFW_MODE = 3.
2. Set MD32610 $MA_VELO_FFW_WEIGHT = 1.
3. Reset MD32810 $MA_EQUIV_SPEEDCTRL_TIME.
Setting the equivalent time constant with torque feedforward control
If the previous setting was MD32620 $MA_FFW_MODE = 2:
1. Set MD32620 $MA_FFW_MODE = 4.
2. Set MD32610 $MA_VELO_FFW_WEIGHT = 1.
3. Reset MD32800 $MA_EQUIV_CURRCTRL_TIME.
This also applies when you load an older archive into the control system, e.g. from a
previous version. For example, when changing MD32620 $MA_FFW_MODE from 1 to 3,
MD32810 $MA_EQUIV_SPEEDCTRL_TIME may not simply retain its old value, but must be
reset. Otherwise, no improvement will be achieved, but rather a worsening of the positioning
response.
Recommended setting in case of recommissioning
If recommissioning, or if previous standard values are loaded (switch position 1 on
commissioning switch and POWER ON), the following machine data default values apply:
MD32620 $MA_FFW_MODE = 1
MD32610 $MA_VELO_FFW_WEIGHT = 1
These are not the recommended settings, but are chosen for reasons of compatibility.
However, if recommissioning, the following setting is recommended:
MD32620 $MA_FW_MODE = 3
The balancing time for the speed feedforward control then just has to be adjusted in machine
data:
MD32810 $MA_EQUIV_SPEEDCTRL_TIME.
Velocities, Setpoint/Actual-Value Systems, Closed-Loop Control (G2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Detailed Description
2.5 Optimization of the control
2-63