Knick Stratos Pro A401B PH, User Manual

Page: 106 / 196

106
Controller Functions
with:
Y
P
Proportional action
T
N
Reset time [s]
T
D
Rate time [s]
K
C
Controller gain [%]
Constant 5 (for pH)
500 mV (for ORP)
Controller equations
Neutral zone
Tolerated deviation from desired value.
With the setting “1 pH”, for example, a deviation of ± 0.5 pH from the
desired value is tolerated.
+100 %
50 %
X
w
Process variables: pH/ (mV),
underneath: temp [K]
Con
tr
oller
output Y
K
C
= 500 %
K
C
= 200 %
K
C
= 100 %
K
C
= 50 %
1 / (100) 2 / (200) 3 / (300) 4 / (400)
Proportional action (Gradient K
C
[%])
Deviation
5 / (500)
[10] [20] [30] [40] [50]
Controller output Y =
I action D action
dY
P
dt
1
T
R
P action
Y
P
+ Y
P
dt + T
D
Proportional action Y
P
Setpoint - Meas. value
Constant
Y
P
=
* K
C