SAMWONTECH
4st Edition of TEMI2000_Series IM : Aug. 18. 2009 Page 20 / 55
3.4 AUTO TUNING and TUNING POINT
▶
The Hold and Step keys cannot be used while the program is in running with auto-tuning.
▶
Auto-Tuning is a strong function to establish optimal P.I.D value automatically by calculating the
characteristics of the control system.
▶
While generating ON/OFF control output signal for 2.5 cycles, the controller measures the PV
response of the control system with a limit cycle method and calculate the optimal P.I.D value with the
oscillation data.
▶
Auto-Tuning process can be carried out on FIX / PRORGAM RUN state, and after completion of Auto-
Tuning process, calculated P.I.D value with SP will be automatically stored on P.I.D parameters of
corresponding zone.
▶ Auto tuning procedure with a set point
Parameter
Settings
▶ Operation method : FIX operation
▶ Input sensor : Temperature(PT_1)
▶ Range : -50.00℃ ~ 150.00℃
▶ Auto-Tuning Point : 0.10% → EUS 0.10% = 0.2℃
▶ SP : 50.0℃
▶ OL : 0.0%
▶ OH : 100.0%
Tuning
Procedure
▶
Auto Tuning Precautions
①
The tuning point does not change even if the SP is changed during auto tuning. When auto tuning has
completed, operation continues again with the changed SP.
②
If ‘S.OPN’ occurs during auto tuning, the process stops. PID stays the same before auto tuning.
③
Auto tuning stops automatically, if the second cycle is operated longer for 27 hours.
④
PID may change during auto tuning, but when the process is finished, the PID will be reset to new
calculated value from auto tuning process.
⑤
If auto tuning is terminated by force, the PID is the same value as it was before auto tuning began.
☞
A more accurate PID can be obtained if temperature is auto tuned in a stable temperature before
auto tuning humidity.
OH
OL
MV
PV
ON
ON
OFF
OFF
50.2℃
Process of auto tuning
PID Control
ON
49.8℃
SP = 50.0℃
Auto tuning
point
