HEIDENHAIN iTNC 530 HSCI - Page 820

820 HEIDENHAIN Technical Manual iTNC 530 HSCI
The following calculation can be used to find the damping achieved by
MP1522:
Limit frequency (f) of the feed-rate smoothing
Feed-rate smoothing (MP1522) with known oscillation frequency
 In MP1522, define the time constant according to the formula above for the
feed-rate smoothing.
 Begin the adjustment with a smoothing of the feed rate in the 6-dB range,
and increase the value step by step.
 Check the following error with a suitable NC program (e.g. feedforward
adjustment program in TNCopt) until it reaches a minimal value.
Typical input value:
MP1522 = Approx. 0.33 to 0.5 ⋅ T
Machine
(T
Machine
= Period of the machine resonance frequency)
Example:
f
Machine
= 50 Hz; T
Machine
= (1 / 20 Hz) = 50 ms;
MP1522 = 0.5 x 50 ms = 25 ms (input value = 25)
MP1522 Feed-rate smoothing
Input: 0 to 60 [ms]
0: Function inactive
fg 6dB()
1
3
---
1000
MP1522
----------------------------
×=
fg 12dB()
1
2
---
1000
MP1522
----------------------------
×=
MP1522 6dB()
1
3
---
1000
f
---------------
×=
MP1522 12dB()
1
2
---
1000
f
---------------
×=
Note
There can be an increase in the following error at corners or contour
transitions (change of direction) of an axis. Therefore, do not choose too
large a value for MP1522, and only use feed-rate smoothing in combination
with the nominal position value filters.