MANUAL
CT
Controllers
OPERATION
Page 37
3 - ORP MAIN MENU
Operation
The ORP sensor is used to monitor and control a true oxidizer
like ozone, or an oxidizing sanitizer, like chlorine or bromine.
In the latter case, the controller monitors and controls the
sanitizer through the oxidation-reduction potential it produces
in the water.
The ORP Menu screen is used to access all the ORP
submenus for Control Mode, sensor calibration, setpoint and
alarm settings and shocking program (superchlorination if
using chlorine).
It also displays the actual run time for individual feed events
and the cumulative run time since last reset to zero.
3.1 - Control Mode
Line 1 shows the Control mode that is currently selected: OFF
(X), Manual (M), AUTO (A), Cycle Timer (T), Percent of Flow
(F), or Daily Schedule (S).
To change the Control Mode, select the first line with the UP or
DOWN ARROW keys and press the RIGHT ARROW key. The
Control Mode screen is then displayed.
The control mode screen and selection procedures are
common to all sensor-based control functions. See CONTROL
Submenu in this Chapter, page II-23.
3.2 - Display and Calibration
The second line displays the current reading of the ORP
sensor in mV and is used to access the Calibration Submenu.
As with all sensor calibrations, the ORP sensor can be
calibrated with 1, 2 or 3-Point calibration for origin, slope and
curvature. This is done by pressing the RIGHT ARROW key to
enter the CALIBRATION Submenu. The calibration procedure
is common to all control functions. See CALIBRATION
Submenu further down in this chapter.
Since the ORP sensor is direct reading and there are no
readily available calibration solutions in the applicable range of
operations for water treatment, it normally does not require
calibration.
For other specialized applications, the calibration value may
be adjusted to allow for differences or changes in ORP sensor
readings.
3.3 - Setpoint
The ORP SETPOINT determines the ORP level that the
CHEMTROL® PC maintains automatically when placed in the
Automatic control mode.
Menu 3
Menu 3.3
Submenus 3.4.1 and 3.5.1
To change the setpoint, press the RIGHT ARROW key and
enter the numerical value with the digital keypad. After
pressing the OK key, the SETPOINT Submenu 3.3 is displayed
asking whether the control is to be set for an Oxidizer, a
Reducer or both.
The CHEMTROL®
CT
Controller
includes one relay outlet
for oxidizer and one for reducer (de-oxidizer) feed. The
normal (default) setting is for an oxidizer. This means that
the oxidizer feed outlet is automatically activated when the
sensor reading falls below the setpoint.
ORP
AUTO
Calibrate
mV
750
Setpoint
mV
700
Alarm Low
mV
650
Alarm High
mV
850
Time Limit
min
30
Run Time
10
125
Last Shock
05/01/04
SETPOINT
Oxidizer
Reducer
Both
ALARM OPTIONS
Feed lockout
YES
Alarm buzzer
YES