KROHNE OPTISENS PAC 050 EN - Manual (Page 18)

Manual OPTISENS PAC 050
OPTISENS PAC 050 18
You can choose between three different controller versions:
ON/OFF controller
The ON/OFF controller switches ON if the measured value exceeds the set point and OFF if it drops back
below it or vice versa. Dosage is always carried out with 100% (ON) or 0% (OFF). The parameter for an
ON/OFF controller is the hysteresis.
P controller
The P controller or proportional controller reduces the dosage in the vicinity of the set point proportional to
the control deviation. This is easily achieved if the analog output is used as steady control output. If the
relays are used, the proportional reduction is achieved by either reducing the switch frequency (Impulse-
frequency controller) or reducing the time within a given period of time in which the relay is ON (pulse-pause
controller).
The parameters for a P controller are the P range and the impulse- frequency or the pulse+ pause time and
the minimum pulse.
PI controller
The PI controller is a P controller with an additional I function. Adjustments and parameters are the same as
for a P controller. Additionally the integral action time has to be adjusted which determines the I function.
The I function eliminates the P controller’s disadvantage of a remaining steady-state deviation.
5.1 ON/OFF controller
Main menu
.
.
Set points and
controller version
Set points Set point S1 You can choose different
. 7.50 pH controller versions for S1
. P range S1 and S2
. 0.20 pH
Integral Time S1
000 sec.
Set point S2
6.50 pH
P range S2 Controller settings
0.20 pH .
Integral Time S2 .
000 sec. Direction S1
raise
Basic settings Direction S2
Basic settings . Lower
. Hysteresis
Contr. settings 0.01 pH
For an ON/OFF controller you have to set the following parameters:
1) Set points S1 and S2
Set point S1 refers to relay 1, set point S2 refers to relay 2.
2) P range and integral action time for S1 and S2
For an ON/OFF controller set P range = 0 and integral time = 0.
3) Acting direction for S1 and S2
Select “raise“ if the dosage raises the measured value.
Select “lower“ if the dosage lowers the measured value.
4) Optionally a hysteresis
The hysteresis prevents fast switching in the vicinity of the set point. If hysteresis is activated (by setting a
value > 0) the relay switches only when the set point is exceeded by half the hysteresis.