HEIDENHAIN iTNC 530 Service Manual page 115

Position control MP1396.x allows the operator to switch to velocity semifeedforward control.
with velocity Normally, work will be carried out using velocity feedforward. Velocity semifeedforward is
semifeedforward activated, for example, by an OEM cycle before roughing, in order to permit a higher following
control error and thereby a higher velocity, combined with a lowered accuracy, in order to traverse
corners.
Before finishing, another OEM cycle can be used to switch back to velocity feedforward, in order
to finish with the highest accuracy possible.
In order to use velocity semifeedforward, a factor must be entered for every axis in MP1396.x,
where values toward 0 control the following error more, and values toward 1 control the velocity
feedforward more.
As soon as a factor between 0.001 and 0.999 has been entered in MP1396.x, the kV factor from
MP1516.x becomes effective.
The values for position monitoring are interpolated according to the factor in MP1396.x between
the values for servo lag (MP1710.x, MP1720.x) and the values for velocity feedforward control
(MP1410.x, MP1420.x).
Feedback control with
following error (servo
MP1391 bit x = 0
MP1392 bit x = 0
MP1396.x = nonfunctional
May 2006
Note
For axes that are interpolated with each other, the kv factors must be equal. In this case the
smaller kV factor determines the input value for these axes.
Feedback control with velocity
lag)
MP1391 bit x = 1
MP1392 bit x = 1
MP1396.x = 0.001
semifeedforward
MP1396.x = 0.999
Feedback control with
velocity feedforward
MP1391 bit x = 1
MP1392 bit x = 1
MP1396.x = 1
11 – 115