8.4.2.5 '12.SFCT' Setpoint function
Possible settings: ● Lin
● 1 - 25
● 1 - 33
● 1 - 50
● n1 - 25
● n1 - 33
● n1 - 50
● FrEE
Purpose: This parameter is used to linearize nonlinear process valve char‐
acteristics. Optional flow characteristics as shown in the figure in
the '13.SL0' ... '33.SL20' Setpoint turning point (Page 149) param‐
eter description are simulated for linear process valve characteris‐
tics.
Factory setting: Lin
Seven process valve characteristics are stored in the positioner and are selected using the
'SFCT' parameter:
Process valve characteristic Set with parameter value
Linear Lin
Equal percentage 1:25 1-25
Equal percentage 1:33 1-33
Equal percentage 1:50 1-50
Inverse equal percentage 25:1 n1-25
Inverse equal percentage 33:1 n1-33
Inverse equal percentage 50:1 n1-50
Freely adjustable FrEE
8.4.2.6 '13.SL0' ... '33.SL20' Setpoint turning point
Setting range: 0.0 ... 100.0
Purpose: These parameters are used to assign a flow coefficient in units of
5% to each setpoint turning point. The setpoint breakpoints form a
polyline with 20 linear segments which models the process valve
characteristic; see figure below.
Factory setting: "0", "5" ... "95", "100"
Parameter assignment
8.4 Description of parameters
SIPART PS2 with 4 to 20 mA/HART
Operating Instructions, 11/2019, A5E00074631-AE 149
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