Omron EJ1 User Manual page 97

Setting Control Specifications
Note
76
AT Calculated Gain
Sets the gain used when calculating the PID constants in autotuning. When
emphasizing flexibility, decrease set value. When emphasizing stability,
increase the set value.
AT Hysteresis
The limit cycle operation during autotuning has a hysteresis when switching
ON and OFF. This parameter sets that hysteresis value.
Limit Cycle MV Amplitude
Sets the MV amplitude during limit cycle operation in autotuning.
Note This parameter is disabled for 100% AT.
Temporary AT Execution Judgment Deviation
When autotuning has been executed, temporary autotuning will be executed if
the deviation specified in this parameter is exceeded.
Note This parameter is disabled for 100% AT.
40% AT
• The width of MV variation in the limit cycle can be changed with the Limit
Cycle MV Amplitude parameter. In this case, autotuning will take longer to
execute than it does with 100% AT.
• The timing of the limit cycle's onset depends on whether the deviation at
the start of autotuning (DV) is less than the Temporary AT Execution
Judgment Deviation.
Deviation ≥ Temporary AT Execution
Judgment Deviation
Process
Limit Cycle
value
MV Amplitude 40%
Set point
Temporary AT
Execution Judgment Deviation
(Default: 150.0)
Autotuning starts Autotuning completed
100% AT
• When autotuning starts, it operates as shown below regardless of the
deviation (DV). When you want to shorten the time it takes for autotuning,
select 100% AT.
The Limit Cycle MV Amplitude and Temporary AT Execution Judgment Devia-
tion parameters are disabled.
Process
value
Set point
Autotuning starts Autotuning completed
Process
value
Set point
Time
Autotuning starts
Limit Cycle
MV Amplitude 100%
Time
Section 4-3
Deviation < Temporary AT Execution
Judgment Deviation
Limit Cycle
MV Amplitude 40%
Temporary AT
Execution Judgment Deviation
(Default: 150.0)
Autotuning completed
Time