Siemens SINUMERIK 840D sl Function Manual page 903

This feedforward control mode can be further optimized for a more secure symmetrization
process by changing the axis-specific machine data:
Machine data
MD32810 EQUIV_SPEEDCTRL_TIME
MD37200 COUPLE_POS_TOL_COURSE
MD37210 COUPLE_POS_TOL_FINE
MD37220 COUPLE_VELO_TOL_COURSE
MD37220 COUPLE_VELO_TOL_FINE
In such cases, higher threshold values for the synchronism signals and larger position and/or
speed tolerances result in more stable results.
Dynamic response adaptation
The FS and the coupled LS must have the same dynamic response to setpoint changes. The
same dynamic response means that their following errors must be equal at any given speed.
The dynamic response adaptation function in the setpoint branch makes it possible to obtain
an excellent match in the response to setpoint changes between axes, which have different
dynamic characteristics (control loops). The difference in the equivalent time constants
between the dynamically "weakest" spindle and the other spindle in the coupling must be
entered as the dynamic response adaptation time constant.
Example
When the speed feedforward control is active, the dynamic response is primarily determined
by the equivalent time constant of the "slowest" speed control loop.
Lead spindle:
MD32810 $MA_EQUIV_SPEEDCTRL_TIME [n] = 5 ms
Following spindle:
MD32810 $MA_EQUIV_SPEEDCTRL_TIME [n] = 3 ms
Time constant of dynamic response adaptation for the following spindle:
MD32910 $MA_DYN_MATCH_TIME [n] = 5 ms - 3 ms = 2 ms
The dynamic response adaptation must be activated axially via MD32900
$MA_DYN_MATCH_ENABLE.
The dynamic adaptation setting can be checked by comparing the following errors of the FS
and LS (in Diagnosis operating area; Service Axes display). Their following errors must be
identical when they are operating at the same speed!
For the purpose of fine tuning, it may be necessary to adjustservo gain factors or
feedforward control parameters slightly to achieve an optimum result.
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Synchronous Spindles (S3)
14.4 Special features of synchronous mode
Description
Equivalent time constant speed control loop for
feedforward control
Threshold value for "Coarse synchronism"
Threshold value for "Fine synchronism"
Velocity tolerance 'coarse'
Velocity tolerance 'fine'
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