3
INSTALLATION
EARTH GROUND
When making installations, the
magnetic flow meter grounding rules
have to be observed. The sensors
of the QSE flow meter are sensitive
to any electrical noise that is always
present in piping systems. The fluid
in piping systems usually carries
significant levels of static electricity
and should be grounded for the QSE
meter to be at its best performance.
As part of the installation, it is
important to understand the
importance of having the QSE meter
connected to “earth ground”. Earth
grounding helps ensure electronic
component stability and reliability
by using the earth to absorb any
static charge buildup or spurious
signal noise that can affect the meter
electronics. Earth ground in this
installation is NOT the ground wire in
the customer isolated power supply.
Process Fluid Grounding
Establishing a process fluid ground
is one of the most important
installation details. Proper process
fluid grounding ensures that the
sensor and fluid are at the same
electrical potential so that only the
induced flow signal is measured. The
process fluid grounding provides
a stable base potential reference
for measuring the induced flow
signal (the differential between the
base potential reference and the
fluid flow potential created by the
sensor magnetic field). Process fluid
grounding should be established
on both sides (upstream and
downstream) of the sensor elements.
By connecting the QSE sensor,
the fluid, and the reference used
by the internal electronics to a
stable, noise free reference point
(earth ground), the user is ensured
of getting the best performance
from their magnetic flowmeter.
Each QSE meter has a ground
lug with a removable ring terminal
located in the circular wall adjacent
to the outlet end of the meter. This
ground lug is connected internally
to the electronics and sensors and
is the meter connection to earth
ground (the base potential reference).
Grounding Summary:
1. Ground sensor to meter
ground lug. (Done at factory.)
2. Ground electronics to meter
ground lug. (Done at factory.)
3. Ground process fluid to
meter ground lug. (Customer
responsibility.) Various process
fluid grounding examples are
shown on the following pages
(
see Figures 1,2, 3, and 4
) to
assist you in completing this
item. The examples cover various
meter installation situations.
4. Ground meter ground lug to earth
ground. (Customer responsibility)
All of the examples on the following
pages show 14-16 AWG ground
wire (customer supplied) being
used. A ground wire should be
crimped to the ring terminal on the
meter ground lug and the other
end of the ground wire connected
to earth ground (item 4 above).
