HEIDENHAIN PT 855 for Milling - Manual (Page 110)

II - 6 Switching Inputs and Outputs
108 Technical Information POSITIP 855
128
Reset actual value display to zero
You can reset the actual value display of each axis to zero.
Minimum pulse duration for zero reset: t
min
³ 100 ms
Zero reset signal: make contact against 0 V or
input pulse over TTL logic device (such as SN 74 LS XX):
U
H
³ 3.9 V (U
MAX
= 15 V)
U
L
£ 0.9 V with I
L
£ 6 mA
Using the switching signals
If you wish to use the switching signals, you must supply POSITIP
with 24 V d.c. at the D-sub connection EXT (pins 23 to 25; 0 V to
pin 10). Pins 14 to 21 will then be supplied with 24 V as long as the
display value is not within a switching range.
These pins are then assigned to the axes with operating parameter
P60.x. As soon as a display value is within the switching range, the
voltage to the corresponding pin will be cut off.
Define the switching range in operating parameter P61.x sym-
metrically about zero.
If the location of the datum point changes,
move the switching ranges correspondingly.
Axis assignment: P60.x
No axis assigned (Off): P60.x = 0
Assigned to axis 1: P60.x = 1
Assigned to axis 2: P60.x = 2
Assigned to axis 3: P60.x = 3
Assigned to axis 4: P60.x = 4
Define switching range: P 61.x
0 to 99 999.999 [mm] symmetrically about zero P61.x
Permissible load at switching outputs
I
MAX
= 100 mA
Ohmic resistance
Danger to internal components!
Connect inductive loads only with a quenching
diode parallel to the inductance.
Accuracy of switching ranges and switching delay: P 69
You can select the switching delay and the accuracy with which
the switching outputs are switched.
You can choose between
• Accuracy = display step; switching delay = 80 ms
-> Mode 1:P 69 = 0
• Accuracy =
Grating period GP of encoder
Switching delay = 5 ms -> Mode 2:P 69 = 1
P60.2 P61.2 P61.2
X:
0
– +
Fig. 50: The switching ranges are symmetrical
about zero