HEIDENHAIN TNC 335 Technical Manual - Manual (Page 154)

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TNC 360 3 Servo Positioning of the NC Axes 4-57
Calculation of the smallest voltage step:
The controls produce an analog voltage 0 to 10 V.
In the TNC 360 the 10 V analog potential is produced by a 14 Bit A/D converter, giving 16 384
divisions. The resulting smallest potential step is 0.6 mV.
Potential steps per µm positional deviation:
As described above, moving with the rapid traverse (MP1010) results in a certain lag distance s
a
.
The rapid traverse rate is reached at a definite voltage (MP1050). So one can calculate a definite
potential
∆
U per µm of positional deviation (lag).
∆
U = MP1050 [mV] / s
a
[µm]
If
∆
U is divided by the smallest voltage step which can be produced (0.6 mV), the result is the
number of voltage steps which are produced per 1 µm positional deviation.
n =
∆
U [mV]/0.6 [mV]
Example:
k
v
= 2 rapid traverse 5 000 [mm/min], U = 9 [V]
s
a
=
5 000 [
µ
m]
2
= 2 500 [µm]
∆
U =
9 000 [mV]
2 500 [
µ
m]
= 3.6 [mV/µm]
n =
3.6 [mV/
µ
m]
0.6 [mV]
= 6 steps/µm positional deviation