Inputting The Freely Programmable Characteristic - Burkert 8792 Operating Instructions Manual

Standardised valve stroke [%] (POS)
Fig. 40: Characteristics
In the case of control tasks for closed-loop control systems it is usually particular demands which are placed on the
course of the operating characteristic, e.g. linearity. For this reason it is occasionally necessary to correct the course
of the operating characteristic in a suitable way. For this purpose the positioner features a transfer element which
implements different characteristics. These are used to correct the operating characteristic.
Equal percentage characteristics 1:25, 1:33, 1:50, 25:1, 33:1 and 50:1 and a linear characteristic can be set.
Furthermore, a characteristic can be freely programmed via nodes or automatically calibrated.
21.3.3. inputting the freely programmable characteristic
The characteristic is defined via 21 nodes which are distributed uniformly via the position set-point values ranging
from 0 – 100%. Their distance is 5%. A freely selectable stroke (adjustment range 0 – 100%) is assigned to each
node. The difference between the stroke values of two adjacent nodes must not be larger than 20%.
FREE
* If the sub-menu is left by pressing the selection key on the left (ESC), the value remains unchanged.
Fig. 12: Operating structure CHARACT FREE
96
SELEC
EXIT
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Position set-point value [%]
CMD
INPUT
y 0 ->: 0.0%
OK
INPUT
y 5 ->: 5.0%
OK
INPUT
y 100 ->: 100%
OK
Type 8792, 8793 Type 8792, 8793
Start-up, operation
position controller Type 8792
+
*
y 0 ->: 0.0%
-
+
*
y 5 ->: 5.0%
-
+
*
y 100 ->: 100%
-