Burkert Type 8620 - Manual (Page 99)

mxCONTROL Type 8620
Page 99
14.3.2 PI-Control (COND_PI)
This module permits a Proportional Integral (PI)-Control of the conductivity with an optional interface to
the "Biocide-Dosing" module. The functionality is same as in the conductivity On/Off-Controller
COND_CONTROL, except the internal PI-Controller.
These modules
are explained
below.
Figure 39:
COND_PI
Pre-bleeding and "Biocide Dosing" Module
It is the same module as described in the chapter above, (Chapter 14.3.1 in the section "Pre-bleeding
and "Biocide Dosing" Module".
PI Controller
The description of the Proportional Integral (PI)-Controller is consistent to the PI-part of the PID
Controller in section “PID Controller” in chapter 14.2. Specifics / differences are described below.
Proportional part / Module sense of action:
The normal module sense of action is defined:
Proportional part: Yp[%] ) ( PV SP Kp
− ∗ − =
It can be illustrated as shown in the following figure:
Lim+
Lim-
PV
Proportional
Controller Output
SP
Module - sense of action: normal
Lim+
Lim-
PV SP
Module - sense of action: inverted
Proportional
Controller Output
Figure 40:
Sense of action of the
modules
(COND_PI
and
COND_PI_RATIO)
Deadband:
A deadband doesn’t exist for this module.