Hach-Lange SI794 D tr User Manual - Manual (Page 79)

Proportional action Y
P
Process variables: % / (mg/L, ppm)
Proportional action (Gradient K
C
[%])
Deviation
Neutral zone (Y=0)
Tolerated deviation from desired value.
Example: With the setting “010 %”, a deviation of
± 5 % does not activate the controller.
X
w
10 / (1.00) 20 / (2.00) 30 / (3.00) 40 / (4.00)
100 %
50 %
Co
nt
ro
lle
r
output Y
K
C
= 500
% K
C
= 200
%
K
C
= 100
%
K
C
= 50
%
50 / (5.00)
with:
Y
P
Proportional action
T
R
Reset time [s]
T
D
Rate time [s]
K
C
Controller gain [%]
Constant 50 % (for % O
2
or % Air)
5.00 mg/L (for mg/L)
5.00 ppm (for ppm)
Controller equations
Controller output Y = Y
P
+ Y
P
dt + T
D
I action D action
dY
P
dt
P action
1
T
R
Setpoint - Meas. value
Constant
Y
P
=
* K
C
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