1
The CRS451 is a sealed gage sensor and when not submerged will read approximately 1 bar at
sea level and less as elevation increases. The CRS451 is calibrated at nine 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,
nonrepeatability, 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).
CAUTION:
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.
See
(p. 32) for other units.
CRS451/CRS456 Submersible Water-Level Recording Sensor
5
