13
In this example, ‘Pump B’ will turn on at a pH of 3.5 (set point -
∆
pH) and will turn off when pH reaches 4.0.
It is highly recommended that the hysteresis (pump off function) be used to prevent relay chatter.
The function of the hysteresis is to prevent pump relay chattering. It operates by allowing the pump to be turned on when
the control point plus (or minus) the hysteresis value has been met, but does not allow the pump to turn off until the control
point has been met. The chosen value will be used for both upper and lower set points.
The hysteresis, or dead band, designates how many pH units beyond set point the pump runs before turning off. Any value
from 0 to 14.00 is acceptable. If use of this function is undesirable, set it to 0.
Example:
If the lower set point is pH 4.0 and the hysteresis has been set at 0.50, a falling pH will cause the pump to activate
at pH 3.50 and it will run until reaching set point (4.0).
4.2
Alarms
(1) ...... Press
to display Alarm data.
(2) ...... Press
to program Alarm Point 1 (low pH).
(Pump B)
(3) ...... Press
to save Alarm Point 1 value and to move to
Alarm Point 2.
(4) ...... Press
to program Alarm Point 2 (high pH).
(Pump A).
(5) ...... Press
to save Alarm Point 2 value and to move to
Alarm Hysteresis.
(6) ...... Press
to program Alarm Hysteresis.
This is the point where the alarm turns off.
Controller must be in ‘OFF’ mode to program change Set Points.
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