MANUAL
CT
Controllers
OPERATION
Page 49
X.1.3 - Automatic Sensor Control
In Automatic Control with pH or ORP sensor input, the operator
can choose among two different Control Modes: ON/OFF,
Proportional. Conductivity control uses only ON/OFF control.
X.1.3.1 - ON/OFF Control
In the ON/OFF Control mode, the controller activates the
control outlet until the setpoint is reached, at which point it is
turned off. It is turned on again when the reading is outside of
the deadband.
Selection of the ON/OFF control mode leads to the
DEADBAND submenu screen X.0.1 (see previous page).
The ON/OFF control mode is recommended to obtain fast
corrections to return to the setpoint rapidly, if there is no
concern about overshooting (overfeed). This is particularly
applicable to larger bodies of water.
Proportional Control is recommended for more precise control,
especially in smaller bodies of water,
X.1.3.2 - Proportional Control
In the Proportional Control mode, the controller turns the feed
on and off at a rate varying from 0% to 100% of a 15-minute
time cycle.
Proportional control applies only within the Progressive Zone
(Submenu X.0.2 on previous page).
The wider the Progressive Zone is, the more slowly and
precisely the controller will return to the setpoint. As the width
of the Progressive Zone is decreased, the reaction becomes
faster and faster until eventually one approaches the
conditions of ON/OFF control.
X.1.3.3 - 4-20 mA Control
This type of control is designed for electronic pumps with linear
response to current inputs. It appears on the display only
when the option is installed.
Instead of relays, the controller sends an electronic signal from
4 to 20 mA. The output is proportional to the distance from the
setpoint. For instance, a 4 mA output corresponds to a 0%
feed rate, 12 mA to 50% and 20 mA corresponds to 100%.
The values of the 0 and 100% limits are adjustable for each
function, as shown in submenu X.1.3.3.1 for ORP.
X.1.4 - Cycle Timer
Timer Control mode is available as a temporary control mode if
a sensor is defective or not available.
In this mode, the controller activates the control outlet
according to fixed ON and OFF cycles. Each cycle is
adjustable in 0.1 minutes increments.
Selection of the Bleed lockout function, displayed on line
3, is used when it is desirable to lock chemical feed during
bleed and lock bleed during and after feed. It leads to the
Bleed lockout Submenu X.1.4.2.3 (described above).
Submenu X.1.3.2.1
Proportional Control
Submenu X.1.3.3.1
Submenu X.1.4.1
4-20 mA Limits
ORP Top
850
ORP Bottom
650
AUTOMATIC CONTROL
ON/OFF
Proportional
4-20 mA
CYCLE TIMER
Cycle ON (min)
0.1
Cycle OFF (min)
1.0
Bleed Lockout
YES