Siemens SINUMERIK 808D Function Manual page 51

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● MD32810 EQUIV_SPEEDCTRL_TIME (equivalent time constant speed control loop for precontrol)
The following control parameters must be set to the same value for the leading axis and synchronized axis:
● MD32400 AX_JERK_ENABLE (axial jerk limitation)
● MD32410 AX_JERK_TIME (time constant for the axial jerk filter)
● MD32420 JOG_AND_POS_JERK_ENABLE (basic setting for axial jerk limitation)
● MD32430 $MA_JOG_AND_POS_MAX_JERK (axial jerk)
Dynamics matching
The leading axis and the coupled synchronized axis must be capable of the same dynamic response to setpoint changes.
The same dynamic response means: The following errors are equal in magnitude when the axes are operating at the same
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
equivalent time constants between the dynamically "weakest" axis and the other axis in each case must be specified 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.
Leading axis:
MD32810 EQUIV_SPEEDCTRL_TIME [n] = 5 ms
Synchronized axis:
MD32810 EQUIV_SPEEDCTRL_TIME [n] = 3 ms
Time constant of dynamic response adaptation for synchronized axis:
MD32910 DYN_MATCH_TIME [n] = 5 ms - 3 ms = 2 ms
(time constant of dynamic response adaptation)
Dynamic response adaptation must be activated axially with the following machine data:
MD32900 DYN_MATCH_ENABLE (dynamic response adaptation)
Note
Checking dynamic response adaptation:
For the purpose of fine tuning, it may be necessary to adjust servo gain factors or feedforward control parameters slightly to
achieve an optimum result.
Referencing gantry axes
The positions of the reference points for the leading and synchronized axes must first be set to almost identical values.
To ensure that the synchronization compensatory motion of the gantry axes is not started automatically, during first
commissioning the gantry warning limit must be set to 0 before referencing:
MD37100 GANTRY_POS_TOL_WARNING (gantry axis definition)
This will prevent a warning message being output during traversing motion.
In cases where an excessively high additional torque is acting on the drives due to misalignment between the leading and
synchronized axes, the gantry grouping must be aligned before the axes are traversed. After this, the gantry axes must be
referenced as outlined in the section titled "Referencing and synchronizing gantry axes":
Once the leading and synchronized axes have been referenced, the difference between them must be determined by
comparing the actual position value display on the corresponding screen:
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Function Manual
51
01/2017

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