Advertisement
Simplicity on the Worksite
Using PID Control
The procedure to use PID control is given step by step in this section.
Step 1 Determining the Control Method
1
Select direct or reverse operation.
The default setting is for reverse operation.
For heating control, select reverse operation.
Reverse Operation (Default)
Manipulated variable
100%
Heating
0%
Set point
The manipulated variable
increases if the temperature is
lower than the set point.
2
Adjust the PID constants.
You can automatically or manually set the PID constants that are used for PID control.
Adjusting the PID Constants
The suitable values of the PID constants that are used for temperature control depend on the
characteristics of the controlled object.
There are three ways that you can use to set the PID constants. These are described
below.
If you can allow the temperature to vary while tuning the PID
constants and you need to calculate the optimum PID constants:
If you know the PID constants in advance:
If you cannot allow the temperature to vary and you need to
automatically estimate the PID constants when the set point is
changed:
With self-tuning, calculation of the PID constants is affected by
changes in the temperature, such as when a heater is turned
ON and OFF. The PID constants will be automatically
calculated and set. If there is an external source that causes
temperature changes (such as a heater turning OFF), use
autotuning or set the PID constants manually.
Temperature
The manipulated variable
decreases if the temperature
is higher than the set point.
Solutions Guide for FAQs: E5@N
Using PID Control
For cooling control, select direct operation.
Direct Operation
Manipulated variable
100%
Cooling
0%
Set point
The manipulated variable
The manipulated variable
decreases if the temperature is
increases if the temperature is
lower than the set point.
higher than the set point.
⇒
Use autotuning (AT).
Set the PID constants
⇒
manually.
⇒
Use self-tuning (ST).
Temperature
3-1
Advertisement
