HEIDENHAIN TNC 335 Technical Manual - Manual (Page 158)

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TNC 360 3 Servo Positioning of the NC Axes 4-61
➀ When operating with feed forward control the set velocity value (the analog potential for
the drive amplifier) is formed from three components:
feed forward control,
servo lag,
integral component.
➁ The feed forward control value, which is adjusted to the dynamic characteristics of the
machine by machine parameters, makes it possible to control the loop with a lag distance
which is nearly "0".
➂ Deviations in the actual positional value are compensated as described under "Operation
with lag." The servo follows the pre-compensated curve.
The Kv factor for the feed forward control then comes into play.
➃ If the axes are stopped, the integral factor will also be effective:
it results in an offset correction.
The feed forward control value is adjusted to the dynamics of the machine by three machine
parameters.
U [V]
t [ms]
MP1060
MP1520
MP1530
Pre-control
9
Entry value correct
Entry value too large
Entry value too small
The machine parameter MP1060 determines the acceleration (= slope of the pre-controlled speed
curve).
The machine parameter MP1530 determines the transient response. The larger the value which is
entered, the more the system will tend to oscillate.
MP1520 determines the run-in behavior into the nominal position. The larger the value which is
entered, the more the system will tend to oscillate.
The fine control of the pre-controlled speed set-value is influenced by the Kv factor for feed forward
control MP1510.