74
[1] If there is a large difference between the SV and PV as the temperature is rising
When AT bias is set to 20 , the AT process will fluctuate at the temperature 20 lower than
the SV.
(1) Calculates PID constant
(2) PID constant calculated
(3) Controlled by the PID
constant set by AT
(4) AT bias value
(Fig. 11-1)
[2] When the control is stable
The AT process will fluctuate around the SV.
(1) Calculates PID constant
(2) PID constant calculated
(3) Controlled by the PID
constant set by AT
(Fig. 11-2)
[3] If there is a large difference between the SV and PV as the temperature is falling
When AT bias is set to 20 , the AT process will fluctuate at the temperature 20
higher than the SV.
(1) Calculates PID constant
(2) PID constant calculated
(3) Controlled by the PID
constant set by AT
(4) AT bias value
(Fig. 11-3)
(1)
(2)
(3)
(4)
AT starting point
SV
Temperature
Time
AT starting point
(1)
(2)
(3)
Temperature
SV
Time
AT starting point
(1)
(2)
(3)
(4)
Temperature
SV
Time
Temperature 20 higher than the SV
Temperature 20 lower than the SV