17
2009 AT8 M anual
WArNINg
Sensors are shipped with a protective cap covering the electrode tip to protect the sensing element. Sen-
sors should be kept in the protective cap until ready for installation, if the sponge in the boot becomes dry,
wet it with tap water. during shipment, air bubbles may have entered the electrode, carefully shake the
electrode downward (like a thermometer) to dispel the air from the sensing elements inside the
electrode. before using the sensor, remove the cap.
CHAPTER 4
SENSORS
The AT-8 can accept readings from a wide variety of sensors. Each sensor has its own unique circuitry that is con-
nected directly to the micro-controller for measurement. Isolation of each sensor ensures more accurate measure-
ments.
The AT-8 measures the following sensor measurements with the listed characteristics:
pH
Range: 4.22 to 9.78, ±0.02.
This measurement is temperature compensated.
WARNING: Sensors are shipped with a plastic case covering the electrode tip.
Sensors should be kept in the protective cap until time of installation. If the
sponge in the cover becomes dry, wet it with tap water.
ORP
Range: 0 to 999 mV, ±1mV.
WARNING: Sensors are shipped with a plastic case covering the electrode tip.
Sensors should be kept in the protective cap until time of installation. If the
sponge in the cover becomes dry, wet it with tap water.
Flow Switch
This input measures if a switch is open or closed.
pH electrodes sense the acidity of the water and work with any acid or base. The blue bands on the cables identify
the pH sensors. Each sensor is also identified on the sensor body. ORP electrodes are used to monitor the Oxidation-
Reduction Potential (sanitization quality of the water) of a given solution. The sensing element of the ORP electrode
is made of a precious metal such as platinum or gold. The red bands on the cables identify ORP sensors.
4.1 pH and ORP Sensors
The AK10K sensor can be installed to measure/display temperature. The sensor should be installed as close as
possible to where the water comes from the pool. If temperature probe is installed in the AK1200
flow cell there will be a
temperature variation due to the long tubes and the temperature in the pump room. A common place to install it is in the
small plugged hole in the bottom of the main pump strainer basket.
The sensor uses a special ¼” NPT fitting to hold the stainless steel sensor. A hole should be drilled (7/32”) and
tapped (1/4”) where the water enters the pump room through a fitting to get double the depth to hold the sensor. If in
-
stalled outdoors make sure to keep it out of direct sunlight. Route the wires into the controller through a strain relief and
connect to the temperature input. The red wire goes to T and the black wire to gNd.
4.2 Temperture Sensor
