OTT PLS - Installing the Pressure Probe; Installation Type A: Fixed Mounting

5 Installing the pressure probe
The OTT PLS pressure probe can be used in a variety of ways, for example in
observation wells and boreholes from 1" diameter, in shafts, open waterways, and
in waterways that do not always hold water.
Caution
We do not recommend installing the pressure probe in the vicinity of port facilities,
industrial waste water discharges or areas with heavy chemical contamination.
The pressure probe is constructed from high-quality stainless steel and plastic.
However, depending on the mounting location, damaging corrosion can arise. For
more information on the materials used, see Chapter 11 "Technical data".
The pressure probe can be installed in two ways:
䊳
fixed in an individual protective device, built on location, or
䊳
hung on the pressure probe cable.
Caution
No moisture should be allowed to enter the pressure compensation capillary of the
pressure probe cable during installation! Very high air humidity can also lead to
the formation of water droplets in the pressure compensation capillary due to
temperature changes. These inevitably lead to unusable measurement results! As a
result, ensure the transport protection is left on the cable end during the whole
time it is being laid!
5.1 Installation type A: fixing the pressure probe into a protective
device
In flowing waters or waterways with a swell, the pressure probe must be fixed.
With strong currents (> 0.5 … 1 m/s) the hydrodynamic influences of the station
have to be considered in the installation. Depending on the version and mounting
of the individual components, overpressure or negative pressure can arise that can
affect the measurement result.
䡵 Determine the minimum and maximum water level at your station (e.g. staff
gauge, contact gauge). Use both values to specify the probe position. The
following conditions must be fulfilled:
– position the probe below the minimum water level if possible;
– difference between max. water level and position of the probe < measuring
range of the probe.
䡵 Fix the pressure probe according to your individual requirements in a protective
device, as shown in Figure 2, for example.
Note
The fine setting of the probe position is carried out, for example, by entering a
reference or offset value (with SDI-12/RS-485 interface) or using a scaling func-
tion of the datalogger connected.
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