17. Add-on Controller
84
Dr. A. Kuntze
I
Gutes Wasser mit System
Robert-Bosch-Str. 7a
40668 Meerbusch
+49 (0) 2150-7066-0 / Fax -60
www.kuntze.com
17.1.1. ON/OFF controller
The ON/OFF controller doses with 100% until the measured value reaches the set point, and then stops.
Besides set point and controller type you can set the following
parameter:
Hysteresis
For the on/off controller you can define a hysteresis. This prevents constant switching of the relays
in the vicinity of the set point – the relay switches only when the difference between set point and
measured value exceeds half the hysteresis value.
17.1.2. P controller
The P controller reduces the dosing when the difference between set point and measured value is
smaller than the specified P range. Within the p range, the controller output is proportional to the
remaining deviation. When the measured value reaches the set point, dosing stops.
Besides set point and controller type you can set the following
parameters:
P range
The P range or proportional range is the range in which dosing is reduced proportional to the deviation
between set point and measured value. The bigger the P range, the softer the control.
To find the ideal setting, start with a big P range and reduce it until the measured value oscillates
around the set point in a stable manner. The ideal value is then twice the current value. If the measured
value still oscillates, use a slightly higher value.