9
Proportional, Integral & Derivative
(PID)
PID staging allows the Controller to determine when
the next stage is required to turn on or off. The
Controller automatically determines the settings that
are manually selected in the proportional mode.
After each stage is turned on in the firing sequence,
the Controller waits a minimum amount of time before
turning on the next stage. After the minimum time
delay between stages has passed, the Controller
examines the control error to determine when the next
stage is to fire. The control error is determined using
PID logic.
Proportional
compares the actual operating sensor
temperature to the heater target temperature. The
colder the temperature, the sooner the next stage is
turned on.
Integral
compares the operating sensor temperature
offset (error) to the heater target temperature over a
period of time.
Derivative
determines how fast or slow the operating
sensor temperature is changing. If the temperature is
increasing slowly, the next stage is turned sooner. If
the temperature is increasing quickly, the next stage is
turned on later, if at all.
Heater Mass (BOIL MASS)
The heater mass setting (1, 2 or 3) allows the installer
to adjust the Controller to the thermal mass of different
types of heat sources used. The heater mass setting
automatically determines the interstage differential,
interstage delay on, interstage delay off, minimum on
time and minimum off time of the stages when PID
staging is used. A higher thermal mass setting pro-
vides slower staging, while a lower thermal mass
provides faster staging.
Heater Mass Definitions
Mass 1
Low Volume, High Recovery
Mass 2
Medium Volume, Medium Recovery
Mass 3
High Volume Low Recovery
NOTE:
Always use a heater mass setting of 1 for
Raypak equipment. If the Controller continues to
stage too rapidly, contact Raypak.
Table A: Heater Mass Definitions
Interstage Differential (STG DIFF)
The “interstage differential” is the temperature drop at
which the next stage will turn on. Once a stage turns
on, the next stage cannot turn on until the temperature
drops the “interstage differential” below the tempera-
ture at which the previous stage turned on. The
“interstage differential” is adjustable through the STG
DIFF setting in the adjust menu.
Interstage Delay On (ON DLY)
The “interstage delay on” is the amount of time that
must elapse before turning on the next stage. Once a
stage turns on, the next stage cannot turn on until the
interstage delay on time elapses. The interstage delay
on is adjustable through the ON DLY setting in the
adjust menu.
Interstage Delay Off (OFF DLY)
The “interstage delay off” is the amount of time that
must elapse before turning off the next stage. Once a
stage turns off, the next stage cannot turn off until the
interstage delay off time elapses. The interstage delay
off is adjustable through the OFF DLY setting in the
adjust menu.
Minimum On Time (MIN ON)
The “minimum on” time is the minimum amount of time
that a stage must be on before it is allowed to turn off.
Once a stage turns on, the next stage cannot turn off
until minimum on time elapses. The minimum on time
is adjustable through the MIN ON setting in the Adjust
menu.
Minimum Off Time (MIN OFF)
The “minimum off” time is the minimum amount of time
that a stage must be off before it is allowed to turn on.
Once a stage turns off, it cannot turn on until minimum
off time elapses. The minimum off time is adjustable
through the MIN OFF setting in the adjust menu.
