Controlling Valves (Can Be Used With A Position-Proportional Model) - Omron E5CC User Manual

5 Advanced Operations
5-21 Controlling Valves (Can Be Used with
a Position-proportional Model)
You can use position-proportional control to control a value with a control motor. With position-propor-
tional control, you can use either close control or floating control.
Precautions for Correct Use
The following functions cannot be used with position-proportional control.
• ON/OFF control
• P and PD control during floating control
• 40% AT during floating control
• ST
• LBA
• HB and HS alarms
Control Method
Close control
Floating control
Motor Calibration and Valve Opening Monitor
The valve position is calibrated and the travel time from completely open to completely closed is set
automatically. You can then check the valve opening with the Valve Opening Monitor parameter. If
you set the Motor Calibration parameter to ON, the valve will open completely and close completely,
and then the setting of the parameter will change to OFF when the measurement has been
completed. "ERR" will be displayed if any of the following errors occurs during execution. If an error
occurs, check the wiring and other factors and execute motor calibration again.
• The potentiometer input value does not change or changes backward between completely
open and completely closed because the wiring is wrong.
• The value of the potentiometer input is incorrect because of a broken wire, noise, or other
factor.
Note: Do not change to any other parameter during calibration.
Travel Time
The Travel Time parameter is set to the time from when the valve is completely open until it is
completely closed. The Travel Time parameter is set automatically when motor calibration is
performed.
Note: You cannot monitor the valve opening simply by setting the Travel Time parameter. To monitor the valve
opening, always perform motor calibration.
Position Proportional Dead Band and Open/Close Hysteresis
When the difference between the MV and the valve opening is within the value that is set for the
Position Proportional Dead Band, opening or closing the valve will be stopped to prevent the valve
from deteriorating. The Open/Close Hysteresis parameter is used to offset the ON and OFF points
when opening and closing the valve. Refer to the following figure for details.
5 - 58
A potentiometer is connected and the valve opening and travel time are used to control
valve operation. Always perform motor calibration before actual operation.
Valve operation is controlled without a potentiometer by estimating the valve opening
from the travel time. Always set the travel time before actual operation. To monitor the
valve opening, connect a potentiometer and perform motor calibration.
E5@C Digital Temperature Controllers User's Manual (H174)