34
5.5
Control 1-4 Menu
(FOR PROPORTIONAL CONTROLLERS)
The description of the menus for pulse outputs will apply to Control 1 2, 3, and 4 for WDP440 models,
and to control 1 and 2 for WPH420 and WDP420 models.
The Control menus are separate from each other but operate in exactly the same way. Each menu
provides the following independent settings: Set Point, Prop Band, Control Direction, Min SPM Rate,
Max SPM Rate, Time Limit, Interlock and HOA. The top level menu status line may display the
following messages: Off, Intrlck, Timeout or SPM. "Off" indicates that the output is off.
Ctrl 1 A
Intrlck
Indicates that the output would be on but is not because of a signal from a flow switch or
level switch is stopping control.
Ctrl 1 A
Timeout
Indicates that the output has been on for longer than the maximum time programmed by
the user.
Ctrl 1 A
SPM
Shows the stroke rate of the pump
Hi/LoSet Point
Use the arrow keys to adjust the display to read the desired set point value. Press
ENTER
to accept the change.
Use the arrow keys to adjust how far away from the set point the process value must get before the pump is
stroking at the maximum rate. For example, if the lower set point is 6.00 pH, and the proportional band is 0.5,
then the pump will stroke at its maximum rate when the pH is 0.5 units away from the set point (at pH 5.5).
Prop Band
The following graph shows the effect of the various settings:
If the controller overshoots the set point, make the prop band larger. If the controller can’t keep up with the
additions, make the prop band value smaller, or increase the Max SPM rate value, or source a pump with a higher
flow output.
Control Dir
Press
ENTER
to change the direction of control, then use the Up and Down arrows to toggle between High Set
Point and Low Set Point, and press
ENTER
to make your choice. A high set point will turn on the relay when the
process value goes over the set point value (to add an acid, or reducing agent, or as a high alarm). A low set point
will turn on the relay when the process value goes below the set point value (to add an alkali, or oxidizer, or as a
low alarm). The further away from the set point the process value gets, the faster the pump will stroke.
Min SPM Rate
Use the arrow keys to set the minimum stroke rate of the pump. If you want to stop when the set point has been
reached, enter 0. If you need the pump to run at a certain rate regardless of the set point, enter that stroke rate.
This may be useful in once-through control schemes.
Max SPM Rate
Use the arrow keys to enter the maximum stroke rate of the pump. This may be the maximum that the pump is
capable of, or it may be less if the pump is oversized for your application, but it can NOT be higher than the pump
is capable of, or the pump will not stroke at all.
7
6
5
8
9
0
MAX
PROGRAMMED
SPM
MAX
PROGRAMMED
SPM
CONTROL
RANGE
PROP BAND
OF
0.5
ST
R
O
KE
S PE
R
M
IN
U
TE
LOWER
SET PT
UPPER
SET PT
40
60
80
100
