
4.1 Selecting the Control Method
E5AK
4--3
·
Use the position-proportional type controller for position-proportional
control.
·
On a position-proportional type controller, control output 1 is used for
open output, and control output 2 is used for close output. Accordingly,
control outputs 1 and 2 cannot be used as output assignments. Special
output units are already set on position-proportional type controllers.
·
On a position-proportional type controller, the following functions are
disabled.
ST
MV limiter
P and PD control
40% AT
LBA
HBA
ON/OFF control
·
The travel time is factory-set to “30 seconds.”
·
To change the travel time, either set in the “travel time” parameter
(option mode), or execute motor calibration in the “motor calibration”
parameter (option mode).
·
The valve opening can be monitored when a potentiometer is connected
to the controller. However, be sure to execute motor calibration after
connecting the potentiometer.
·
The monitored valve opening is displayed on the bar graph in 10% incre-
ments.
·
Open, close or hold can be selected as output at stop or PV error. Set these
outputs in the “manipulated variable at stop” or “manipulated variable
at PV error” parameters (level 2 mode).
·
Set the dead band in the “position-proportional dead band” parameter
(level 1 mode).
·
Set the open/close hysteresis in the “open/close hysteresis” parameter
(level 1 mode).
Open/close hysteresis
Dead band
MV--Valve opening
100%
0
-100%
OFF
ON
J
Position-propor-
tional control
F
Travel time
F
Valve opening
monitor
F
Manipulated vari-
able at stop/PV
error
F
Other functions