Auto-Tuning - Fuji Electric PXR4 Instruction Manual

6-2 Auto-tuning (AT)
Auto-tuning is the automatic calculation and entering of the control parameters (P,I and D) into memory. Prior to
the auto-tuning, complete the setting of input range
(P-SL,P-SU, P-dP), a set value (SV), alarm setting (AL1, AL2), and cycle time (TC).
How to start the auto-tuning
Set the parameter AT as either "1" or "2" by using
Then the point indicator at the lower right starts blinking. At the completion of Auto-tuning, the point indicator
stops blinking, then parameter AT is automatically set to 0.
Setting code (AT)
q Standard type (AT=1)
Start of AT
Set value
(SV)
PV
(a) The P.I.D. parameter calculated by auto-tuning remains even if the power is turned off. If the power is
turned off before the auto-tuning is completed, you must restart the auto-tuning.
(b) The PV may be changed greatly depending on the process, because the control output is ON/OFF
action (two position operation) in the auto-tuning. So, do not use the auto-turning if the process does
not allow a significant variation of PV.
In addition, the auto-tuning should not be used in any process such as pressure control and flow
control, where a quick-response is required.
(c) If the auto-tuning isn't completed in four hours, the auto-tuning is suspected to fail. In this case, check
the wiring and parameters such as the control action, input type, etc.
(d) Carry out the auto-tuning again, if there is any change in SV, input range (P-SL, P-SV or P-dP) or
process condition. Perform the auto-tuning if fuzzy control is selected as the control algorithm.
(e) While carring out auto-tuning, PV operates as shown in Figs 1 and 2.
(f) Execute the auto-tuning also when fuzzy control is selected in control type setting.
(g) When resetting the AT parameter, set the parameter to "0" once, then reset it.
When auto-tuning
is cancelled or not
performed.
0
End of AT
PID control
or key, and press the
Standard type
(auto-tuning at SV)
1
w Low PV type (AT=2) : Overshoot decreased
Start of AT
Set value
(SV)
PV
– 19 –
key to start the auto-turning.
SEL
Low PV type (auto-
tuning at 10%FS
below SV.)
2
at tuning.
End of AT
SV-10%FS
PID control