Auto-Tuning (At) - Fuji Electric Model: PXR4 Instruction Manual

6-2 Auto-tuning (AT)

Autotuning 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 con trol 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) When resetting the AT parameter, set the parameter to "0" once, then reset it.
or
When auto-tuning Standard type
is cancelled or not (auto-tuning at SV)
performed.
0
End of AT
Set value (SV)
PID control
– 16 –
key, and press the key to start the auto-turning.
SEL
Low PV type (auto-
tuning at 10%FS
below SV.)
1
w Low PV type (AT=2) : Overshoot decreased
Start of AT
PV
2
at tuning.
End of AT
SV-10%FS
PID control