wtw DIQ/S 182-XT-4, Operating Manual

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System 182-XT-4 Outputs
6 - 31 ba75753e06 12/2014
Within the proportional range an increase of the concentration by 1 mg/
l causes a reduction of the output current by 1 mA. If the measured
concentration is 17 mg/l, for example, 11 mA is output:
The highest concentration at which the controller still works in the
proportional range is 8 mg/l (corresponding to Imin = 8 mA) and the
lowest is 2 mg/l (corresponding to Imax = 14 mA).
Settings
( )
mg/l mg/l
mg/l
mA
1 mA 12 I
Controller
5 4
− ⋅ + =
( )
mA 11 mg/l 1
mg/l
mA
1 mA 12 I
Controller
= − ⋅ + =
Setting Selection/Values Explanation
Measured variable Main variable
Adjoining variable Main variable
designates the actual
measured parameter
of the sensor (e.g.
pH, oxygen, etc.).
Adjoining variable
designates an
additional measured
parameter (e.g.
temperature).
Nominal value Within the measuring
range (sensor-
dependent) Nominal value the
measured value is
regulated to
Xp 5 ... 100 %
-5 ... -100 %
% of the measuring
range Proportional range of
the controller.
Negative values
result in a positive
characteristic curve.
Imin 0 ... 20 mA Lower current
limitation *
Imax 0 ... 20 mA Upper current
limitation *
* Note:
Spacing between
Imin and Imax:
at least 5 mA