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Yoder YS 640
The Controller… In-Depth
This is an in-depth overview of the controller’s feature set.
The controller has been designed to make it as hands-o and user-friendly as possible.
At its most basic level, the cooker has three modes of operation: Heat up, Maintenance
and Cool Down.
Beyond these basic modes are the concepts of aggressiveness, anticipation and mi-
cromanagement that have been learned as the result of many thousands of hours of
testing. When the cooker is displaying maintenance mode, it is not idle. It is constantly
checking and re-evaluating the grill’s temperature and making incremental adjustments
to maintain the cooking temperature as close to the desired set point as possible –
think of it as micromanagement.
Just like in the maintenance mode, the controller is constantly evaluating the grill sta-
tus while in “heat up” and “cool down” modes. This is where “aggressiveness” and
“anticipation” have been written into the program. If the controller senses the grill is
not heating up very quickly, it will increase the pellet feed rate above what the normal
heat up rate would be for a given set point, and it will continue to do so until the heat
up rate is where it should be. The inverse is true of the cool down mode – if the grill is
not cooling fast enough, the controller will get more aggressive with cool down until the
grill temperature is where it should be.
How the Heat Up Modes Work
In addition to the intelligence previously described, the program also contains three in-
ternal heat up modes. Left on its own, the controller makes a series of small incremen-
tal adjustments as described above. The various heat up modes are designed to speed
the heat up process.
The selection of the heat up modes is automatically selected by the program. At start-
up the program automatically begins in H1, eight minutes into the startup cycle the
program calculates the dierence between the set point and the actual cooker tem-
perature and changes the “H” mode if necessary. The program will make the same
calculation again at the 12-minute mark, and if an “H” mode other than the mode
currently running is required, the program makes the required change. If a mode other
than H1 has been selected it will remain in that mode until it breaks that target set point
at which time the program will enter maintenance mode.
Once the controller enters maintenance mode, the pit temperature must rise or fall 35
degrees above or below set point before the program enters the heat up or cool down
mode.
