10.5.16 Drift compensation
Drift compensation: Machine data
Axis-specific ($MA_ ...)
Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
Digital drives are not subject to drift or compensate for it automatically.
Because ADI4 does not support acyclic services on the PROFIBUS DP, drift
compensation must be performed manually by entering the appropriate
compensation value in the axial machine data
MD36720 DRIFT_VALUE (basic drive value)
Manual drift compensation is performed with the axis at zero speed as follows:
– Zero speed of the axis
– Axis enables pending
The drift causes constant traversing of the axis. To compensate for the drift,
the compensation value is incremented/decremented step by step depend-
ing on the direction of the drift until the axis reaches zero speed.
The drift causes a constant following error or position setpoint , 0. To com-
pensate for the drift, the compensation value is incremented/decremented
step by step depending on the direction of the drift until following error or
position setpoint = 0 is displayed.
Operating area switchover > Diagnosis > Service displays > Service
If an axis is used for the function DSC (Direct Servo Control)
MD32640: STIFFNESS_CONTROL_ENABLE (dyn. stiffness control) = 1
drift compensation must not be enabled for that axis.
Drift compensation causes extreme speed fluctuations during switch-on/off of
the DSC function.
Basic drift value
10 NC Start-Up with HMI Advanced
10.5 Axes and spindles