Campbell CS450, Instruction Manual

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CS450/CS455 Pressure Transducer
Only SDI-12 instructions aM!, aM7!, and aM8! output the results obtained
when using the multiplier and offset. The offset and multiplier is only applied
to the pressure/level value, not to the temperature.
3.2.2.2 Sample Number
The extended SDI-12 command used to configure sample numbers is
“aXCONFIG2=nnn!”, where nnn is the number of samples that will be
measured to obtain the final output value, which is an average of the samples
taken. This value only applies to the “aM8!” command. The integration time is
a result of the number of samples selected. This value can be derived by adding
2 seconds to the number of samples. For example, if nnn = 50, then 50 samples
would be averaged. The integration time for this process is 50 plus 2, or 52
seconds.
4. Installation
The CS450/CS455 is designed for water-level measurements. Typical
applications include agricultural water level/flow, water wells, lakes, streams,
and tanks. If the device is to be installed in a liquid other than water or in
contaminated water, check the compatibility of the wetted material. The CS455
should be used in harsh-water applications, including salt water.
4.1 Vent Tubes
A vent tube incorporated in the cable vents the sensor diaphragm to the
atmosphere. This eliminates the need to compensate for changes in barometric
pressure.
To prevent water vapor from entering the inner cavity of the sensor, the vent
tube opening should terminate inside a desiccated enclosure or a desiccant
tube. Moisture inside the vent tube can cause erroneous data and damage to
the sensor.
4.2 Dislodging Bubbles
While submersing the sensor, air bubbles may become trapped between the
pressure plate and the water surface, causing small offset errors until the
bubbles dissolve. Dislodge these bubbles by gently shaking the CS450/CS455
while it is under water.
Do not hit the sensor against the well casing or another
solid surface while dislodging the bubbles; this could
damage the sensor.
CAUTION
4.3 Water Depth
For water-level measurements, the CS450/CS455 must be installed below the
water at a fixed depth. This depth should be chosen so that the water pressure
will never exceed the sensor’s pressure range. Otherwise, the output reading
will not be correct, and the sensor can be damaged if pressure is excessive (2X
full scale).
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