WIKA Operating Instructions Level Transmitter
– BLM-SF-FM
15
4.2.2.3 Adjustment of the transfer function
The characteristic curve of the analogue output can be selected. The cor-
relation between the PV range and the analogue 4-20 mA value is calcu-
lated by a transfer function PV (x) -> analogue output (a). The digital, via
HART available values are not altered by this function (except the current
value). Therefore, it is possible to control e.g. a valve with a non-linear flow
curve directly with the analogue output of the transmitter.
Access:
Setup -> 4-20 mA -> Transfer function
The possible settings are:
Setting
Description
Linear
x
a
(*) standard
x^(1/2)
x
a
x^(3/2)
3
x
a
x^(5/2)
5
x
a
x^2
2
x
a
See also: HART command 47.
