JUMPFLEX SIgnal Conditioners
and Isolation Amplifiers
01788 568008
WHY DO
WE NEED
ISOLATION?
or process control
applications, taking accurate
measurements of parameters
such as voltage, current,
temperature, pressure and flow is an
integral part of operations. These are
measured using a variety of sensors,
however signals can be affected by radio
frequency interference (RFI), transient
signals, common-mode voltages, and
fluctuating ground potentials. This makes
it difficult to measure parameters and
guarantee accuracy, particularly when
you consider the wide array of electrical
equipment, and potential sources of
interference, in a typical plant.
F
One solution to this is to use a 4 to
20mA current signal to transmit the
measurement. Passive sensors will require
additional hardware to achieve this, while
active sensors typically have electronics
built in that can provide a conditioned
output, which can then be transmitted
without any noise pickup or loss of signal
strength.
However, transmitting measurements
in this way can open up the possibility
of ground loops, whereby the sensor
and instrument have different ground
references. As a result, parts of the signal
are transmitted via ground, rather than via
the analogue line. To accurately measure
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PECM Issue 26
an analogue signal, the sensor and the
measuring device should share a common
ground point, yet this can be difficult
to achieve with interference from other
equipment. Longer cable runs, and the
resistance generated as a result, can also
make ground loops difficult to eliminate,
creating the potential for inaccurate
measurements. To further compound
matters, it’s not easy to predict where
ground loops will occur, and they are
sometimes not apparent until equipment
has been installed and powered up.
An effective solution to this is to use an
isolation amplifier. This breaks the ground
loop by isolating the input circuit from
the power supply and output circuit,
preventing unwanted current flow and
ground loops to enable perfect signal
transmission and measurement. A major
advantage is that it can be easily installed
after the original application, allowing
engineers to use them as and when
they’re required, rather than trying to
predict ground loops at the design stage.
WAGO’s JUMPFLEX signal conditioner and
isolation amplifier are available in variants
of just 6 mm wide, making them ideal for
confined cabinet spaces, as well as offering
safe, effective isolation for applications.
A common profile means multiple
JUMPFLEX devices can be commoned
together which reduces wiring, while
pluggable connection technology and
a large choice of configuration methods
streamline installation.
Isolation amplifiers are suited to any
application where ground loops prevent
accurate measurements. They are also
particularly useful for boosting signals
to compensate for losses caused by long
cable runs. Process industries such as
offshore, chemicals, medical and food &
beverage require precise measurement
to ensure quality and safety, and isolation
amplifiers improve accuracy. This can
help to reduce production errors and
equipment shutdowns.
For more information about JUMPFLEX
signal conditioners and isolation
amplifiers, contact Product Specialist Phil
Thompson at WAGO on 01788 568008.