Campbell CRS451, Руководство пользователя

Страница: 12 / 40

CRS451/CRS456 Submersible Water-Level Recording Sensor
4
Weighted and NPT Material: Stainless Steel
Dimensions
Length:
22.23 cm (8.75 in)
Diameter: 2.22 cm (0.875 in)
Weight : 230 g (0.51 lb)
1
The CRS451 is a sealed gauge sensor and when not submerged will read
approximately 1 bar at sea level and less as elevation increases. The CRS451 is
calibrated at 9 pressures starting at 0.6 bar up to full scale referenced to 1 bar.
Points below 1 bar are used in the calibration for the benefit of those who deploy
this sensor at elevations above sea level.
2
The accuracy specification listed pertains to the level of accuracy that the
CRS451/CRS456 is able to measure pressure. If a barometric pressure sensor is
used to remove the component of atmospheric pressure from the pressure reading
provided by the CRS451/CRS456 while submerged in a column of water vented to
the atmosphere, the error of the barometric sensor must be considered when
calculating the resulting accuracy of the water level reading.
3
Total Error Band (TEB) includes the combined errors due to nonlinearity,
hysteresis, non-repeatability, and thermal effects over the compensated
temperature range, per ISA S51.1.
6. Installation
The CRS451/CRS456 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 CRS456
should be used in harsh water applications, including salt water.
6.1 Appropriate Depth
The CRS451/CRS456 must be installed below the water at a fixed depth. This
depth should be chosen so that the water pressure will never exceed the
transducer’s pressure range (twice its pressure rating).
The output reading will not be correct, and the transducer can
be damaged if pressure is twice its pressure rating.
Pressure can be converted to feet of fresh water using the following simple
equation:
1 psi = 2.31 feet of water
For example, the maximum depth with a pressure range of 0 to 7.25 psig is 16.748
feet of water.
6.2 Avoiding Freezing Conditions
Expansion of water due to freezing will irreparably damage the CRS451/CRS456.
The CRS451/CRS456 can be safely deployed in freezing conditions if the sensor
is placed below the frost line. In a lake or channel of moving water, often the
sensor can be placed deep enough to avoid freezing. In shallow conditions, where
CAUTION