Gain Scheduling - Barnstead 30400 Operation Manual

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Gain Scheduling

G.SP: Gain Scheduling
Gain scheduling is the automatic transfer of control
between two sets of PID values. The 2416 controller
does this at a presettable process value. Gain schedul-
ing is used for difficult control processes which show
large changes in their response time or sensitivity at
high or low temperatures, or when heating or cooling.
The G.SP gain schedule setpoint is factory set at 700°
C. The G.SP must be adjusted to 200°C from the
desired setpoint temperature when tuning.
Setting the Transfer Point
If gain scheduling has been enabled, "G.SP will appear
at the top of the PID list. This sets the value at which
the transfer will occur. When the process value is
below this level, PID1 will be active and when it is
above, Pid2 will be active. Set a value between the
control regions that show the greatest change to
achieve the best point of transfer.
Tuning
The two sets of PID values can be manually set or
automatically tuned. To tune automatically you must
tune above and below the transfer point G.SP. If the
process value is below the transfer point G.SP, the cal-
culated values will automatically be inserted into the
(SEt 1) set and if the process value is above G.SP, the
calculated values will automatically be inserted into the
(SEt 2).
Autotuning
The Autotune feature automatically sets up the PID val-
ues in the control parameters to suit new process con-
ditions.
To tune your furnace using autotuning:
1. Load your furnace with a load similar to your
normal load and close the door.