Chapter 10 Built-in PID Functions
10 - 25
(5) Control Object
The current system uses a water level control system as the control object. A water level control system is
a stem to maintain a desired water level by pumping water into a water tank whose lower part has a small
opening for outflow of water. The water in the tank flows out at a constant rate. The decision to increase or
decrease the water level is based on the water inflow. The structure of a water level control system is
shown below.
Pump
Inflow
Outflow
Water
level
Water level
sensor
Driver
Water
tank
10.7.2 Program example 1
The following figure shows a program example of performing PID control using analog modules.
(In this program, the PID constant value and SV value are set in the Variable Monitor window.)