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system or run the auto-tune again. For detailed information on how to tune the
controller, please read the section 10 for tuning the controller.
10. Auto-Tune
This section can be ignored if you are using the controller to control the Bradley Smoker
because the controller already set for it.
The controller's most powerful feature is its ability to regulate virtually any cooker with
stable temperature control. For stable temperature control the controller requires two
things; (1) the controller must be set to the correct power level (see next section) and,
(2) that it must be
tuned
to the cooker being used. Tuning is the process that matches
the control characteristics of the controller to the heating characteristics of the cooker.
The controller is said to be tuned to the cooker when its memory is programmed with
values telling it how fast the cooker warms up, cools off, and how efficiently it transfers
heat. For example, consider the difference between a heat lamp and a hot plate. When
electricity is applied to a heat lamp it begins to heat instantaneously, and when it's
turned off it stops heating instantaneously. In contrast, a hot plate may take several
minutes to begin heating when electricity is applied and even longer to start cooling
when electricity is turned off. But, to do this it must be programmed with the time
constants. Describing how fast the heater heats when electricity is turned on and how
fast it begins to cool when it's turned off. These time constants are called the
tuning
parameters.
Every type of cooker has its own unique set of tuning parameters. For the controller to
heat with stability, it must have programmed with the tuning parameters for the cooker
currently being used.
When Should the Controller be Tuned?
If the PID parameters we provided are not working for your liking, you can use the auto-
tuning function to let the controller to determine the PID parameters automatically. Auto-
tuning function (it’s often known as self-tuning) can automatically optimize the PID
parameters for your chosen cooking system. The auto-tuning function will heat up your
cooker then let it cool down. It will repeat this heat/cool cycle several times. Based on
the response time of the whole cooking system, the controller will calculate and set the
PID parameters for your cooker.
