YSI 5200A
157
YSI 5200A
156
PID/PWM and PID 4/20mA control systems are considered active whenever er-
ror exists away from the configured set point. PID/PWM and PI 4/20mA control
systems are flexible and can be tuned to keep water systems around their set points
even though the environment is exposed to disturbances that drive the input value
away from set point. An example of a PID control system that most readers will
be familiar with is a cruise control system in a car. Acceleration and deacceleration
adjustments are continually being made to maintain the car at a constant speed
or set point.
PID/PWM and PID 4/20mA control mode allows configuration of high and low
alarm systems which alarm systems activate peripheral devices and/or provide alarm
notification messages when alarm condition(s) exist.
Follow page links below for example of instrument menus displayed for PID control
mode:
-PID/PWM and PID 4/20mA control mode example - page 176;
Notes:
-
Changing control method between PID and Set Point may result in invalid
setp point, control and alarm value configurations. Always reconfirm sensor
setup system menu configuration when control mode is changed.
-
PID control is not available for aux digital systems.
-
DO system(s) PID set point can be configured using either mg/L or %Sat.
In contrast to the Set Point Control mode - page 153, when a system is operating
in PID/PWM or PID 4/20 mA control mode there are no user configured control
values. Instead control relays energize anytime a value is reported that is away from
the set point and the output
on time
is proportional to certain conditions and values
being reported to the 5X00.
PID/PDW and PID 4/20mA menu configurations are described in following sections.
-Interval - see page 158
-Gain - see page 159
-Reset Interval - see page 158
-Up or down control - see page 157
An example of a PID control mode system configuration is provided at page 176.
Configuring the 5200A
.
PID 4/20mA Control Mode
A PID (Propotional, Integral and Derivative) 4/20mA control mode system uses
an IOEM 4/20mA output device to control the system. The 4/20mA output control
device is wired (at an IOEM instrument) - see IOEM/REM Safety and Installation
Guide>chapter 3>directions to wire 4/20mA outs for wiring directions and config-
ured (using AquaManager) - see IOEM/REM Safety and Installation Guide>chapter
4>configure IOEM 4/20mA output for configuration directions.
PID/PDW Tuning
Each and every water system responds very differently to peripheral control de-
vices due to many factors. Factors that can influence the ability of a control device
to maintain a certain set point include size of system, peripheral equipment such
as pumps, lighting, system location and the like. While PID/PWM tuning is an
important and necessary requirement to properly configure the control system
it is outside the scope of this document to describe the tuning process. There is a
wealth of information available on the www as well as in print. Please familiarize
yourself with additional information in order to further your understanding of the
PID/PWM control method.
AquaManager includes a PID Tuning tool which allows simulation of various control
action values and functions. The PID tuning tool should be helpful in mimicking
your system through simulation. The AquaManager PID Tuning tool is explained in
detail in the AquaManager Help System. At AquaManager Help Contents>Working
with Nodes>PID Tuner.
Set Point
Configure the set point to be the value at which you’d like the system to ideally
operate at. DO set point can be configured in either mg/L or %Sat at the. Configure
at PID mode menu.
Control Up/Down
Configure the PID/PDW control system to either control up (Falling, to create a
control action to reduce down the system water parameter value) or control down
(Rising, to create a control action to increase up the system water parameter value).
A PID/PDW control can be used only to control the system by either driving the
system value up or down. A PID control cannot be used to drive the system value
both up and down.
NEW
Configuring the 5200A
