Hach-Lange 3400 sc - Manual (Page 14)

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General Information
Figure 7: Boiler/Condensate Sensor
2.3 The Digital Gateway
The Digital Gateway was developed to provide a means to use existing analog sensors
with the new digital controllers. The gateway contains all the necessary software and
hardware to interface with the controller and output a digital signal.
2.4 Theory of Operation
The Contacting Conductivity Sensors are designed to accurately measure
conductivity/resistivity/TDS/salinity from ultrapure water (0.056 µS/cm) to 200,000 µS/cm
in clear fluids. Conductivity is a measure of the ability of a solution to conduct an electric
current and resistivity is the measure of the ability of a solution to resist an electric current.
Total Dissolved Solids (TDS) is a measure that reflects the amount of solids dissolved in a
water sample and salinity is a measure of the dissolved salts in a solution.
Each sensor is available in a variety of precisely measured cell constants and different
materials to meet many measurement needs and are ideal for deionization, reverse
osmosis, electro-deionization, desalination, chemical purity, and other clear fluid
applications.
Each sensor is individually tested to determine its absolute cell constant (shown on its
label as K =X) and temperature element value (to the nearest 0.1 ohm). The cell constant
(K) and temperature factor (T) are entered during instrument configuration or calibration to
ensure the highest possible measurement accuracy.
Available cell constants include: 0.05, 0.5, 1.0, 5.0, and 10. The temperature element was
designed to provide fast response to changes in temperature and ensure high
measurement accuracy.