YOKOGAWA UP35A, User Manual

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8-18
IM 05P02D41-01EN
8.3 Setting PID Control Mode (ALG)
Description
There are two PID control modes: standard PID control mode and fixed-point control
mode.
Select a PID control computation formula shown in the following table according to the
control mode or operation mode.
Operation mode
Program
operation
PRG+AUTO
Program
operation (when
in hold operation)
PRG+AUTO
Local operation
LOC+AUTO
Standard PID
control mode
Deviation derivative
type
PV derivative type
(output bump at SP
change)
PV derivative type
(output bump at SP
change)
Fixed-point
control mode
PV derivative type
(output bump at SP
change)
PV derivative type
(output bumpless at
SP change)
PV derivative type
(output bumpless at
SP change)
PV Derivative Type PID
This is a PID control method in which the derivative action works only on the PV.
It can also eliminate output bump due to SP changing operation in Local mode.
The following shows the PV derivative type PID control computation formula.
e e
P
OUT + + dt Td ΔPV = 100
Ti
1
dt
d ∫






• •
where OUT: control output, e: deviation (PV-SP), P: proportional band, Ti: integral time,
Td: derivative time, and ∆PV: PVn-PVn-1 (n-1: value before one control period)
PV Derivative Type PID (output bump at SP change)
SP
PV OUT
PV Derivative Type PID (output bumpless at SP change)
SP
PV OUT