ATI
Q45D/60 Dissolved Oxygen System
Part 5 – Configuration
O & M Manual
Revision C (7/09)
39 -
use the UP and LEFT arrow keys to select the desired
numerical value. Press ENTER to store the new value.
PID Setpnt
[Iout1=PID]
The measured value which the controller is attempting to
maintain by adjusting output value. It is the nature of the
PID controller that it never actually gets to the exact value
and stops. The controller is continually making smaller and
smaller adjustments as the measured value gets near the
setpoint.
PID Prop
[Iout1=PID]
Proportional gain factor. The proportional gain value is a
multiplier on the controller error (difference between
measured value and setpoint value.) Increasing this value
will make the controller more responsive.
PID Int
[Iout1=PID]
Integral is the number of “repeats-per-minute” of the action
of the controller. It is the number of times per minute that
the controller acts on the input error. At a setting of 2.0 rpm,
there are two repeats every minute. If the integral is set to
zero, a fixed offset value is added to the controller (manual
reset.) Increasing this value will make the controller more
responsive.
PID Deriv
[Iout1=PID]
Derivative is a second order implementation of Integral, used
to suppress “second-order” effects from process variables.
These variables may include items like pumps or mixers that
may have minor impacts on the measured value. The
derivative factor is rarely used in water treatment process,
and therefore, it is best in most cases to leave it at the
default value. Increasing this value will make the controller
more responsive.
AC POWERED UNITS ONLY
*Set 4 mA #2
*Set 20 mA #2
[temp/D.O.]
These functions set the second 4 mA and 20 mA current
loop output points for the transmitter. The output may be set
to track temperature (default), PPM oxygen, or % Saturation.
The values stored for the 4 mA point may be higher or lower
than the value stored for the 20 mA point.
