Xylem DIQ/S 281 Operating Manual page 123

DIQ/S 281
ba76226e02
ti
td
The control parameters result in the following (negative) characteristic curve:
Current I [mA]
Imax 14
Io 12
Imin 8
0
figure 6-18 Characteristic curve for application example
The controller works with the following amplification:
6 mA
= =
K
6 mg/l
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 con-
centration is 5 mg/l, for example, 11 mA is output:
=
I 12 mA
Regler
= +
I 12 mA
Regler
The highest concentration at which the controller still works in the propor-
tional range is 8 mg/l (corresponding to
2 mg/l (corresponding to
03/2023
0 s (no I algorithm)
0 s (no D algorithm)
Xp
2 4
Nominal value
mA
1
mg/l
mA
(
+ ⋅ −
4 5
1 mg/l
mg/l
mA
( )
⋅ − =
1 1 mg/l 11
mg/l
Imax =
14 mA).
8
Measured value [mg/l]
)
mg/l
mA
Imin =
8 mA) and the lowest is
Outputs
123