96
Chapter 7
535-PROF User's Manual
Applications
NOTE:
Adaptive tuning is not
available with velocity position
proportioning control.
d. Change the output percentage and observe if the valve stabilizes at
the new value.
e. If the valve oscillates, increase the
P.PROP.D.B.
value by 0.5%;
repeat until oscillation stops.
12. Set the parameter
S/W BREAK
to define the output value for when the
slidewire breaks.
F. VELOCITY POSITION PROPORTIONING
CONTROL
Velocity position proportioning does not utilize direct feedback. It estimates the
position of the actuator, based on time and the speed of the actuator.
In automatic control mode, the controller will display “CW” to refer to energizing
of the clockwise relay, and “CCW” to refer to energizing of the counterclockwise
relay. A blank display means that both relays are de-energized.
In manual control mode, the display is blank unless an output change is being
made. Use the and
keys to change the output; the relay is only energized
while the keys are being pressed. The display indicates the percentage change
in valve position in real time. The rate of change is dependent on the values
entered for
CCW TIME
and
CW TIME
.
The controller will transfer to manual control due to a lost process variable (
PV.
BREAK
), a digital input closure (
DES.OUTPT.
), a power-up sequence
(
PWR.UP:OUT.
), or lost communications (
SHED OUT
). In these cases, the
output can be set to: remain at its last value with both relays de-energized (OUTS
OFF); rotate fully counterclockwise (CCW); or rotate fully clockwise (CW). CCW
and CW will energize the respective relay for a period two times that of the
CCW
TIME
or
CW TIME
.
Hardware Configuration
•
The controller must have mechanical relay, solid state relay or DC logic
modules installed in the first two output sockets.
Refer to the section on Chapter 1 for more information.
Software Configuration
1. Go to
CONFIG.
menu.
Set
CTRL. TYPE
to POS. PROP.
2. Go to the
CONTROL
menu.
Set
P.P. TYPE
to VELOCITY.
3. Set
CCW TIME
to the amount of time (in seconds) it takes for the actuator
to fully rotate in the counterclockwise direction.
Set
CW TIME
to the amount of time (in seconds) it takes for the actuator to
fully rotate in the clockwise direction.
Loads on the valve may affect the time required, therefore, it is best to measure
these values when the valve is in service. As an alternative, enter the values
specified by the actuator manufacturer and then make adjustments later.
4. Set
MIN. TIME
to the minimum amount of time the controller must specify
for the motor to be on before it takes any action.
5. Set values for
PV. BREAK, DES. OUTPT., PWR.UP:OUT.
and
SHED OUT.
NOTE:
P.PROP.D.B.
can only be
configured if the Slidewire Feedback
is wired to the controller.
