Siemens SINUMERIK 840D sl Function Manual page 917

● K
● Feedforward control parameters
References:
/FB2/ Function Manual Extended Functions; Compensations (K3)
Behavior during loss of synchronism:
● axis-specific MD32620 $MA_FFW_MODE
We would recommend setting the feedforward control mode of the following axis to speed
feedforward control with Tt symmetrization MD32620 = 3.
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
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
factor (MD32200 $MA_POSCTRL_GAIN)
V
MD32620 $MA_FFW_MODE
MD32610 $MA_VELO_FFW_WEIGHT
MD32650 $MA_AX_INERTIA
MD32800 $MA_EQUIV_CURRCTRL_TIME
MD32810 $MA_EQUIV_SPEEDCTRL_TIME
S3: Synchronous spindle
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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