Aalborg DPC, Operating Manual

Page: 29 / 128

25
15.77 15.77
PSIA
25.7 25.7 C
Sml Sml
min
min
SL: SL: 0.0 Sml/min 0.0 Sml/min
0.0 0.0
A
15.77 15.77
PSIA
25.7 25.7 C
Sml Sml
min
min
SL: SL: 25.0 Sml/min 25.0 Sml/min
25.0 25.0
A
15.77 15.77
PSIA
25.7 25.7 C
Sml Sml
min
min
SL: SL: 0.0 Sml/min 0.0 Sml/min
2 .0 2 .0
A
Figure 17: Changing Local Set Point value
Move the joystick UP or DN to increase or decrease digit value between 0-9 and decimal
point. Move the joystick RIGHT or LEFT to move the cursor to another digit position. When
the desired Set Point value is entered, use joystick equivalent of an ENT button to accept (to
be saved in the EEPROM) the new value. Once saved, the new Set Point value will appear on
the bottom of the screen and big digit fl ow reading will be restored.
NOTE: In order for controller to execute requested set point, the Valve Mode
must be set to Auto .

CAUTION: Do not allow set points more than zero when controller’s Valve
Mode set to “Auto” and has zero differential pressure or does not have
enough differential pressure to execute the requested fl ow. With these
conditions the controller’s PID loop will apply maximum power to the valve
in order to reach the requested fl ow rate and valve may reach very
high temperature!

DPC controller Valve Mode can be set in the one of the 3 following modes: Closed, Auto,
Opened . The normal operating mode is “Auto” . While controller's Valve Mode set in “ Auto ”
it executes the set point according to the selected set point source. If controller's valve mode
set to “
Close ” the valve will be closed regardless of the value of the set point. If controller's
valve mode set to “ Open ” the valve will quickly switch to fully open (maximum control cur-
rent) and user can expect huge uncontrolled fl ow (based on the differential pressure across
the valve) through the instrument regardless the value of the set point.
This mode can make
valve very hot and must be limited to no longer than 15 minutes.
To change the Valve Mode from main PI screen move the joystick RIGHT . The PI screen will
be replaced with subsequent screen (see Figure 18 ) and the "Valve Operating Mode" menu
items will be listed. Move the joystick UP or DN to highlight required mode and press joysticl
ENT to accept (activate).
Valve Operating Mode:
Close
Auto
Open
Figure 18: Valve Mode Menu Selections