Installing The Sensor; Desiccant Use; Grounding Issues - Seametrics PT2X Instructions Manual

INSTALLATION

Installing the Sensor

The PT2X measures pressure. The most common application
is measuring liquid levels in wells and tanks. In order to do
this, the sensor must be installed below the water level at a
fixed depth. The installation depth depends on the range
of the sensor. One (1) PSI is equal to approximately 2.31
feet of water. If you have a 5 PSI sensor, the range is 11.55
feet of water and the sensor should not be installed at a
depth below 11.55 feet. If the sensor is installed below its
maximum range, damage may result to the sensor and the
output reading will not be correct.
Note: If you are using an absolute sensor and
you want to enter a depth-to-water reference
after data is collected, then see page 19 before
proceeding.
• Lower the sensor to the desired depth.
• Fasten the cable to the well head using a weather
proof strain-relief system. When securing a vented
cable, make sure not to pinch the cable too tightly
or the vent tube inside the cable jacket may be
sealed off.
• Take a measurement to insure the sensor is not
installed below its maximum range.
Be sure the supplied cap is securely placed on the weather-
resistant connector at the top of the cable. Do not install
such that the connector might become submerged with
changing weather conditions. The connector can withstand
incidental splashing but is not designed to be submerged.
For vented sensors, install the sensor so that the desiccant
tube will not flood or lie in water.
The sensor can be installed in any position; however, when
it leaves the factory it is tested in the vertical position.
Strapping the sensor body with tie wraps or tape will not
hurt it. Seametrics can provide an optional 1/4" NPT input
adapter which is interchangeable with the standard end
cone for those applications where it is necessary to directly
attach the sensor to a pipe, tank, or other pipe port. If the
sensor is being installed in a fluid environment other than
water, be sure to check the compatibility of the fluid with
the wetted parts of the sensor.
Seametrics • 253.872.0284

Desiccant Use

On vented sensors a desiccant tube prevents moisture in
the air from being sucked into the vent tube, which can
cause erratic readings and sensor damage.
The desiccant tube is filled with blue silica gel beads. A
locking barb and a hydrophobic water filter are attached to
the end of the desiccant tube. This filter prolongs the life of
the desiccant as much as three times over a desiccant tube
without the filter.
Install the sensor so that the desiccant tube and cable
connector will not flood or lie in water.
The desiccant is a bright blue color when active and dry. See
Maintenance section for care and changing of desiccant.

Grounding Issues

It is commonly known that when using electronic
equipment, both personnel and equipment need to be
protected from high power spikes that may be caused by
lightning, power line surges, or faulty equipment. Without
a proper grounding system, a power spike will find the path
of least resistance to earth ground—whether that path is
through sensitive electronic equipment or the person
operating the equipment. In order to ensure safety and
prevent equipment damage, a grounding system must be
used to provide a low resistance path to ground.
When using several pieces of interconnected equipment,
each of which may have its own ground, problems with
noise, signal interference, and erroneous readings may be
noted. This is caused by a condition known as a Ground
Loop. Because of natural resistance in the earth between
the grounding points, current can flow between the points,
creating an unexpected voltage difference and resulting
erroneous readings.
The single most important step in minimizing a ground loop
is to tie all equipment (sensors, dataloggers, external power
sources, and any other associated equipment) to a single
common grounding point.
connecting the shield to ground at the connector end.
Page 10
PT2X INSTRUCTIONS
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