Burkert 8693 - Page 68

67
Type 8692, 8693
english
Start-up, operation
position controller Type 8692
4.3.1 CHARACT
Select the transfer characteristic between input signal (position set-point value)
and stroke
Characteristic (customer-specific characteristic)
Use this auxiliary function to select a transfer characteristic with reference to set-point value (nominal position, CMD) and valve
stroke (POS) for correction of the flow or operating characteristic.
Factory setting: linear
CHARACT
SELEC
linear
EXIT
ENTER
GP 1:25
GP 1:33
GP 1:50
GP 25:1
GP 33:1
GP 50:1
FREE
y 0 ->: 0.0%
y 5 ->: 5.0%
y 100 ->: 100%
EXIT
*
Linear characteristic
Equal percentage characteristic 1:25
Equal percentage characteristic 1:33
Equal percentage characteristic 1:50
Inversely equal percentage
characteristic 25:1
Inversely equal percentage
characteristic 33:1
Inversely equal percentage
characteristic 50:1
User-defined characteristic, freely pro-
grammable via nodes
Fig. 11: Operating structure CHARACT
The flow characteristic k
V
= f(s) indicates the flow of a valve, expressed by the k
V
value depending on the stroke s of the actuator
spindle. It is specified by the design of the valve seat and the seat seal. In general two types of flow characteristics are imple-
mented, the linear and the equal percentage.
In the case of linear characteristics identical k
V
value changes k
V
are assigned to identical stroke changes ds.
(dk
V
= n
lin
⋅ ds).
In the case of an equal percentage characteristic an equal percentage change of the k
V
value corresponds to a stroke
change ds.
(dk
V
/k
V
= n
equalper
⋅ ds).
The operating characteristic Q = f(s) specifies the correlation between the volumetric flow Q in the installed valve and the stroke
s. This characteristic has the properties of the pipelines, pumps and consumers. It therefore exhibits a form which differs from
the flow characteristic.
* Input the nodes see "Inputting the freely programmable characteristic"