YOKOGAWA UT550 User Manual

<Toc> < 5. Parameters >
5-27
IM 05D01C02-41E 3rd Edition: May 31, 2006-00
Precautions in Heating/Cooling Control
• Keep the ratio of the heating-side proportional band (P) to the cooling-side propor-
tional band (Pc) equal to or below 5.
• If neither the heating-side nor the cooling-side is performing ON/OFF control, setting
the integral time (I or Ic) of one side to “0” results in the Integral Time parameters of
both sides being set to “OFF”, irrespective of the integral time setting of the other side.
■ Tips About Position Proportional Control (for position proportional con-
trollers only)
Position proportional control can be of either feedback type or estimating type.
In feedback-type position proportional control, the controller obtains a valve position signal
from a feedback slide-wire resistor attached to a valve.
In estimating-type position proportional control, you set the operating time required for a
valve to change from the fully-closed position to the fully-open position beforehand. With
the preset operating time, the controller controls the valve by estimating its position. In the
case of estimating-type position proportional control, there is no need for feedback input
wiring.
Feedback-type position proportional control is superior to the estimating type in terms of
control performance. When in manual operation, you can directly manipulate the
controller’s output terminals. Pressing the
key sends the valve into opening motion
while pressing the
key sends it into closing motion.
The figure below shows a schematic representation of a loop configured for position pro-
portional control.
Direct action
Reverse
action
M
Motor-driven
valve
Slide-wire resistor
Control
output
Valve position
signal
Feedback
input
Controller
Comp-
arator
Control computation

YOKOGAWA UT550 Specifications

General

Brand	YOKOGAWA
Model	UT550
Category	Controller
Language	English