Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B - Manual (Page 103)

Publication 900-UM007D-EN-E - January 2011
Configuration & Basic Operation 3-33
3.
off will be displayed when AT ends.
Figure 3.64
4. To return to the operation function group, press the
O Key.
Note: The newly configured value or parameter is loaded into controller
memory if you do NOT operate any key on the front panel for at least
2 seconds or by pressing the
O
or M key.
Note: When control characteristics are already known, either from experience
or from a previous AT cycle, the PID parameters can be configured
directly from the keypad to adjust control. PID parameter values are set
in the Proportional Band (P), Integral Time (I), and Derivative Time
(D) parameters in the Adjustment function group.
ST (Self-Tuning)
Figure 3.65 — Self-Tuning Function
In the ST (Self-Tuning) function, the 900-TC controller continually executes
step response tuning (SRT) from the start of program execution or when the
set point is changed to calculate the PID constants to match the actual control
target.
Once the self-tuning PID constants have been calculated, ST is not executed
during the next control operation cycle as long as the set point remains
unchanged
.
ST is executed when the ST parameter is set to ON in the Initial Setting
function group.
When the ST function is in operation, make sure to turn ON the power supply
of the load connected to the control output (MV) simultaneously with or
before starting operation of the Bulletin 900 controller. If power to the
controller is turned ON before turning ON load power, self-tuning will not be
performed properly and optimum control will not be achieved.
25
0
PV