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The next three parameters - Proportional Band, Integral and Derivatives - are the three control
parameters of a P.l.D. control system. These parameters will be set when you tune your furnace. (See
Tuning.)
Prop - Proportional Band.
In.t - Integral Time.
dEr.t - Derivative Time.
HPl - High Power Limit (%) This parameter limits the average maximum power that is applied to the
heating elements. Remember that this parameter does not reduce the voltage to the elements. It reduces
the average power to the elements by cycling power on and off.
C/F - Centigrade/Fahrenheit. Choose the desired temperature unit by depressing the "UP" or "DOWN"
pushbutton.
NOTE
All temperature dependent parameters are automatically converted when the temperature
unit (C or F) is changed.
Tuning Your Controller
This programmable control has an automatic tuning feature which installs optimum tuning parameters to
give the best temperature accuracy. No manual loading of tuning parameters is needed. We highly
recommend using this feature to provide the best temperature accuracy the controller can attain. Perform
the following procedures when you first set up your furnace and each time you change your load type,
operating temperature, or program.
To initiate the self tune feature:
Load your furnace with a load characteristic of those you intend to heat in it.
If you will be using the controller as a single Setpoint Controller, set the furnace's setpoint to the
temperature you intend to use for your application.
If you will be running a multi-step program, set the furnace's setpoint to the value of L1 (temp level #1).
Push "PAR" button until TUNE is displayed, then push "UP" or "DOWN" button to turn tune "ON."
During the operation, TUNE flashes in the lower display. Do not make any adjustments to the controller
parameters during this period. The self tuning is finished when TUNE no longer flashes in the lower
display.
Self tuning will calculate values for:
Proportional band - prop
Integral time - Int.t
Derivative time - der.t
• Self tuning cannot be initiated while running a program.
• A power failure will cause the TUNE parameter to revert back to NO. (Reset tune parameter to YES).
• If there are alarm conditions during self tuning, they flash alternately with TUNE.
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