The sensor is a "passive" type. It operates with a constant voltage applied to it by the instrument. If this
source of power is removed from it, for example, if the sensor cable is disconnected from the instrument, the
sensor must be "stabilized" for at least 30 minutes before it is calibrated or used. This is done simply by
connecting the sensor for 30 minutes with the instrument powered on.
Initial "stabilization," described above, will be necessary when the sensor is reconnected after storage. If the
analyzer module suffers a power failure, an internal battery will keep the sensor polarized for 50 hours.
The design of the sensor eliminates the need for frequent changing of the membrane and re-calibration. The
membrane should be replaced only if accidentally damaged. The buffered potassium chloride solution may be
replenished when necessary, without the need to replace the membrane. See later sections for servicing
the sensor.
A temperature measuring thermistor is built into the sensor. It automatically measures the temperature
while the sensor is immersed in the sample water. When measuring chlorine, there is no need to make any
setting on the instrument for temperature since it is automatically' compensated for in the electronic system. In
addition, temperature can be directly indicated on the display when the DISPLAY switch is placed in the
TEMPERATURE position.
All Chlorine sensors require a flow of fresh sample at the sensor tip. The molecules of Chlorine next to the
membrane diffuse through it, and are consumed in the electrochemical reaction. These Chlorine molecule
must be replaced by new ones in the sample flow. The flow must be a least 1 foot per second.
A Refill-Membrane Kit No. 824240 is supplied with the instrument. It consists of a 4 oz. bottle of R-448
Electrolyte with dropper cap and three screw-on membrane caps with the membranes pre-stretched across one
end, ready for use.
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