Xylem WTW DIQ/S 281 Operating Manual page 108

Outputs
Characteristic
curve of the
proportional
controller
Application
example
108
By activating or deactivating the Integral (ti) and Differential (td) controller part,
the following controller types can be configured:
Regulator type
P controller
PI controller
PD controller
PID controller
For a pure P controller the correlation between the measured value and current
I on the controller output results in the following characteristic curve:
figure 6-17 Proportional controller (negative characteristic curve)
The proportional range Xp is limited by the measurement range of the linked
sensor. If a value is entered for the parameter Xp that is greater than zero, the
controller has a positive characteristic curve (example figure 6-17). To obtain a
positive characteristic curve, a negative value must be entered for Xp.
 Regulation of the oxygen concentration
 Sensor: TriOxmatic 700 IQ (measuring range: 0 to 60 mg/l)
Control parameter
Nominal value
Xp
td [s] ti [s]
0 0
0 1 to 9999
1 to 9999 0
1 to 9999 1 to 9999
Value
4 mg/l
10 % of the measuring range
or 6 mg/l
DIQ/S 281
ba77244d01 08/2020