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Control Modes: ON/OFF, PID & Autotune
ON/OFF
• Select ON/OFF if you wish the operation of the heat-
ers to be 100% ON when a demand for heat exists
and 0% once the Set Point Temperature of the Pro-
cess is achieved.
• The Deadband is enabled while in ON/OFF control
mode.
• The Deadband is the temperature range equally
divided above & below the temperature set point,
where the controller will not take corrective action.
o Example: A setting of “10” for the deadband will
result in a deadband that is 5 degrees above and
below the temperature setpoint.
• The deadband is adjustable in 2 degree increments.
It’s default is 10.
PID
• Select PID if you desire PID Control of the load.
• The Proportional Band (P), the Integral (I) & Deriva-
tive (D) are modes of control that work in union to
bring the process variable to setpoint as smoothly
and quickly as possible. They are enabled while in
PID Control mode.
• The P, I & D will be automatically established during
the Autotune procedure (see above).
• Additionally, the P, I & D may all be manually estab-
lished by the user. Great care should be taken when
manually establishing the P, I & D.
• Proportional Band: The temperature band expressed
in degrees within which the controller‘s proportion-
ing action takes place. (Note: The wider the propor-
tional band, the greater the area around the setpoint
in which the proportional action takes place.) This is
sometimes referred to as gain, which is the recipro-
cal of proportional band.
Autotune
• If the Autotune Feature is selected, then the PID pa-
rameters will be calculated and entered by the sys-
tem once the Autotune function has completed its
demand profile function.
• The Autotune function establishes the individual P, I
& D (Proportional Band, Integral & Derivative) control
modes. These modes help to bring the process vari-
able to the setpoint temperature as quickly as pos-
sible.
• In order to properly calculate the P, I & D modes,
the Autotune program requires a 25 degree rise in
sensed temperature after initiating the program. If
within 30 minutes the temperature will not reach its
setpoint, the Autotune algorithm will be canceled
and old PID values will be used.
• Once the Autotune feature is activated, you must not
change the menu page until the Autotune algorithm
is completed. Changing the page will cause the Au-
totune algorithm to shut down.
• The Autotune function is a one-time algorithm set up
of the P, I & D control modes. Should your process
variables change significantly, it is suggested to that
the Autotune feature be turned off and then reiniti-
ated.
Tuning Tab Navigation Notes:
1. Each screen illustrates 6 loops at a time. To make
setting changes to loops beyond the current screen
within the Tuning tab, one must select the Loop Nav-
igation buttons in the upper right or left of screen.
Summary of Contents for IntelliTrace ITAS
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