A
proportional–integral–derivative controller (
PID controller or
three term controller) is a
control loop feedback mechanism widely used in
industrial control systems and a variety of other applications requiring continuously modulated control. A PID controller continuously calculates an
error value e ( t ) {\displaystyle e(t)}
as the difference between a desired
setpoint and a measured
process variable and applies a correction based on
proportional,
integral, and
derivative terms (denoted
P,
I, and
D respectively) which give their name to the controller.
In other words a temperature controller lol. They are used a lot in injection molding which is one of my specialties. I designed the plates (the spacing of the heater cartridges and thermocouple) myself like what is used in injection molding. I see a lot of plates out there that are set up all wrong! Most seem to use one heater cartridge per plate and they put the thermocouple off to a corner somewhere stupid. There are many many years of experience that show how it should be set up. The rods should be centered, two per plate, two and a half inches apart with the thermocouple (temp probe) in the center.