YOKOGAWA UT55A - PD Control (Stable Control in Which a Setpoint Is Not Exceeded)

8-80
IM 05P01C31-01EN
8.2.5 PDControl(StableControlinWhichaSetpointisnotExceeded)
Description
This control type performs control in which integral action (I action) is excluded from PID
action.
Set the integral time (I or Ic) to OFF.
It is useful when stable control in which a setpoint is not exceeded is desired for integral
processes in which constant flows are delivered.
The following shows the PID control computation formula.
MR
∆PV
d
e
P
OUT +








+
=
•
dt
100
Td
whereOUT:controloutput,e:deviation(PV-SP),P:proportionalband,Td:derivativetime,
∆PV:PVn-PVn-1(n-1:valuebeforeonecontrolperiod),andMR:manualreset
The following table shows combination of PD control and control mode (CTLM).
Controlmode(CTLM)
SGL CAS1 CAS2 CAS BUM PVSW PVSEL PVHD
PD control √ N/A √ √ √ √ √ √
√:Available,N/A:
Notavailable
The following table shows combination of PD control and output method.
Outputmethod
Current
output
Time
proportional
output
ON/OFF
output
Position
proportional
output
PD control √ √ N/A √
√:Available,
N/A:
Notavailable
Setting Details
Parameter
symbol
Name
Display
level
Setting range Menusymbol
P Proportional band EASY
0.0to999.9%
When0.0%isset,itoperatesas0.1%.
PID
D Derivative time EASY
OFF: Disable
1 to 6000 s
MR Manual reset EASY -5.0to105.0%
PIDG.
Number of PID
groups
STD
1 to 8 CTL
Note1: The PID number (1 to 8, or R) is displayed on Group display while the parameter P, D, or MR is displayed.
Note
When changing the setpoint of the parameter PIDG., if the setpoint of the parameter PIDN
which belongs to the SP menu is larger than that of the parameter PIDG., the PIDN setpoint is
changed to the PIDG. setpoint.
8.2SettingControlType(CNT)