Specifications

IP 240 Positioning
b) Additive zero offset
The new actual value is computed as follows when you specify an additive zero offset:
Actual
new
=Actual
old
+ Zero offset
add.,new
The actual value thus changes by the value of the additive zero offset transferred.
Fig. 10-20. Additive Zero Offset
Traverse
range
Current
position
Reference point
0 3 000
1 000 4 000
1 500 4 500- 8 500
- 9 000
- 10 000
+11 500
+11 000
+10 000
1 500 4 500- 8 500 +11 500
Limit switch
Limit switch
-10 000 +10 000
NVER=0
1)
Traverse
range
Traverse
range
Traverse
range
NVER=500
3)
NVER=0
4)
NVER=1000
2)
Traverse
range
Explanation: The values NVER=0, NVER=1000, NVER=500 and NVER=0 were transferred in
succession as additive zero offset.
Specifying the zero offset
When you structure the channel, the zero offset (NVER) is transferred to the IP 240 in data words
46 to 47. You can change the zero offset after configuring.
Note the following when specifying the zero offset:
• If the channel is configured for a linear axis, NVER may be in the range from - 9,999,999 to
+ 9,999,999
• If the channel is configured for a rotary axis, NVER must lie between +/- [final value for the
rotary axis].
In addition to the value for NVER, you must also specify the type of zero offset in D45/0 of the
data block (ADD bit).
ADD=0 for a relative zero offset
ADD=1 for an additive zero offset
EWA 4NEB 811 6120-02a 10-27