At (Auto-Tuning) - Omron E5AC-T User Manual

4 Basic Operation
4-9-1

AT (Auto-tuning)

at
4 - 50
• When AT is executed, the optimum PID constants for the set point at that time
are set automatically. A method (called the limit cycle method) for forcibly
changing the manipulated variable and finding the characteristics of the
control object is employed.
• Either 40% AT or 100% AT can be selected depending on the width of MV
variation in the limit cycle. For the AT Execute/Cancel parameter, specify at-2
(100% AT), at-1 (40% AT), ata2 (All PID 100% AT), or ata1 (All PID 40%
AT). To cancel AT, specify off (AT cancel).
• Only 100% autotuning is supported for heating and cooling control or floating
position-proportional control.
• If the Heating/Cooling Tuning Method parameter is set to any value other than
0 (same as heating control), the PID constants are set automatically for both
heating control and cooling control.
• Autoturning cannot be executed while the program is reset (if the reset
operation is set to stop control), while on standby (if the reset operation is set
to stop control), during manual operation, and during ON/OFF control.
• The following operations are not possible during autotuning: changing
settings, hold/clear hold, and segment operations, such as advance
operations.
• Autotuning will stop if the Run/Reset parameter is set to Reset and the Reset
Operation parameter is set to stop control, or if you switch to manual
operation.
• The following operation will be performed if the Reset Operation parameter is
set to fixed SP operation.
• If the Run/Reset parameter is changed to Reset during autotuning, the
present SP will be changed to the fixed SP after autotuning has been
completed.
• If autotuning is executed while the Run/Reset parameter is set to Reset and
the Run/Reset parameter is changed to Run during autotuning execution,
the program will be started after completing autotuning.
• The results of autotuning are reflected in the Proportional Band (P), Integral
Time (I), and Derivative Time (D) parameters of the PID set where autotuning
was started. For details on PID sets, refer to 5-13-1 PID Sets
Adjustment Level
p
Proportional
Band
8.0
i
Integral
Time
233
d
Derivative
Time
40
c-p
Proportional
Band (Cooling)
8.0
c-i
Integral Time
(Cooling)
233
c-d
Derivative Time
(Cooling)
40
E5@C-T Digital Temperature Controllers User's Manual (H185)