Siemens SINUMERIK 840D sl Function Manual page 905

Knee-shaped acceleration characteristic
For the leading spindle, the effect of a knee-shaped acceleration characteristic on the
following spindle is identified by the following axis-specific machine data:
MD35220 $MA_ACCEL_REDUCTION_SPEED_POINT (speed for reduced acceleration) and
MD35230 $MA_ACCEL_REDUCTION_FACTOR (reduced acceleration).
If MD35242 $MA_ACCEL_REDUCTION_TYPE is present, it is also used to configure the
type of acceleration reduction. Otherwise a hyperbolic drop in acceleration is assumed.
If the dynamic response of a following spindle is lower than that of the leading spindle when
the coupling factor is taken into account, the leading spindle dynamic response is reduced to
the required level while the coupling is active.
The acceleration should be constant over the entire speed range for the following spindle.
However, if a knee-shaped acceleration characteristic is also stored in the above-mentioned
machine data for the following spindle, this is only taken into account when the spindles are
coupled in. The setpoints of the following spindle are applied for the specified knee-shaped
acceleration characteristic.
References:
/FB1/ Function Manual, Basic Functions, Acceleration (B2), Section Knee-shaped
acceleration characteristic
Actual value coupling
In an actual-value coupling (AV), the drive for the FS must be considerably more dynamic
than the leading spindle drive. The individual drives in an actual-value coupling are also set
optimally according to their dynamic response.
An actual-value coupling should only be used in exceptional cases.
Speed coupling
The velocity coupling (VV) corresponds internally to a setpoint coupling (DV), but with lower
dynamic requirements of the FS and LS. A position control servo loop is not needed for the
FS and/or LS. Measuring systems are not required.
Threshold values for coarse/fine synchronism
After controller optimization and feedforward control setting, the threshold values for coarse
and fine synchronism must be entered for the FS.
● Threshold value for "Coarse synchronism"
● Threshold value for "Fine synchronism"
The values of the FS must be calculated according to the accuracy requirements of the
machine manufacturer and the PLC interface must be checked via the service display.
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
axis spec. MD7200: AV, DV: COUPLE_POS_TOL_COARSE
MD37220: VV: COUPLE_VELO_TOL_COARSE
axis spec. MD37210: AV, DV: COUPLE_POS_TOL_FINE
MD37230: VV: COUPLE_VELO_TOL_FINE
Synchronous Spindles (S3)
14.4 Special features of synchronous mode
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