8-55
IM 05P02C41-01EN
Control Functions
8.4.2 SwitchingPIDAccordingtoPV
Description
The PID switching according to PV is a function that switches between the groups of PID
parameters according to the PV.
The maximum number of PID groups to be switched is 8. (Set RP1 to RP7.)
This function is useful for reactors in which the chemical reaction gain changes
depending on the temperature.
The figure below shows an example of dividing the PV input range from the maximum
valuetotheminimumvalueintosevenzonesbyreferencepoints1to6.(Set RP1 to
RP6.)
Minimum value of PV input range
Maximum value of PV input range
Reference point 1
Reference point 2
Reference point 3
Reference point 4
Reference point 5
Reference point 6
PID of group 2
PID of group 3
PID of group 4
PID of group 5
PID of group 6
PID of group 7
Change in PV
If the PV is currently positioned at this point,
control is based on the PID of group 6.
ThePVinputrangecanbedividedintothenumberofzonesthatissetinthereference
point.
Hysteresisatthetimeofzoneswitchcanbeset.
► SetpointPD:8.4.6SettingHysteresisatTimeofZoneSwitch
Reference deviation can be set at the same time.
► Reference deviation: 8.4.5 Switching PID according to Deviation (Reference Deviation)
SettingDetails
Parameter
symbol
Name
Display
level
Settingrange Menusymbol
ZON
Zone PID
selection
STD
0: Segment PID selection
1: Zone PID selection (selection
by PV)
2: Zone PID selection (selection
by target SP)
4: Zone PID selection (selection
by SP)
5: Local PID selection
CTL
RP1toRP7
Reference point
1 to 7
STD
0.0 to 100.0% of PV input range
(EU)
(RP1≤RP2≤RP3≤RP4≤RP5
≤RP6≤RP7)
ZONE
PID
PID number
(display only)
EASY
1 to 8, R: PID group for reference
deviation
MODE
Note1: In Cascade control, the LP2 lamp is lit while the Loop-2 parameter is displayed.
Note2: A currently-used PID number is displayed for the parameter PID.
8
8.4SwitchingPID
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