Limit Cycle - Omron E5AR-T User Manual

■ Limit Cycle

4.10 Determining the PID Constants (AT or Manual Settings)
The timing for generating a limit cycle depends on whether or not the
deviation (DV) when AT is begun is less than the Temporary AT
Excitation Judgement Deviation parameter (default: 10.0% FS).
The PV changes as follows during AT:
Present
Deviation 10% FS
value (PV)
Limit cycle MV amplitude 40%
SP
Deviation
10% FS
AT end
AT start
The amplitude of change of the limit cycle MV can be changed in the
Limit Cycle MV Amplitude parameter.
For heating/cooling and position-proportional floating control, the limit
cycle is as shown below regardless of the deviation.
Limit cycle MV
Present
amplitude 100%
value (PV)
SP
AT end
AT start
Present
Deviation < 10% FS
value (PV)
Limit cycle MV amplitude 40%
SP
Deviation
10% FS
Time
AT end
AT start
Time
Time
4-35