ATEX Approval
Digital Pressure Gauges
Keller AG
has introduced no less than five intrinsically safe electronic
pressure gauges for use in areas subject to gas explosion risks.
The type approvals are compliant with the ATEX Explosion Protection
Directive regarding explosive gases. The electronic design of
these devices is trimmed to minimise energy consumption, so it
is also possible to replace the batteries inside areas with explosion
risks.
The simplest version, model ECO 1 Ei, offers high resolution
and reproducibility for both measuring ranges (-1...30 bar and
0...300 bar), together with accuracy (typical) of 0.5 %FS and
an integrated min/max memory. The application range as per the
ATEX directive is defined by identification markings Ex ia IIC
T5 or T6.
Keller's type LEO 1 Ei and LEO 2 Ei electronic pressure gauges
feature microprocessor-assisted compensation to ensure an extremely
narrow total error band (including temperature errors) of only
<0.2 %FS over the entire range of operating temperatures from
0 ... 50 °C. The zero point can be selected freely within
the four measuring ranges between -1 ...3 bar and 0...700 bar.
An automatic switch-off function guarantees energy efficiency.
Both models feature sampling rates of 2 Hz and integrated min/max
memories. The special feature of the LEO 1 Ei is its additional
memory for peak values. In peak mode (as it is known), even extremely
shortlived peak values for system pressure are registered with
a sampling rate of 5'000 Hz. These values are often critical
for the lifetimes of hydraulic plants. For both these pressure
gauges, the application range as per the ATEX directive is defined
by identification markings Ex ia IIC T5 or T6.
Another version of the "Leo" type electronic pressure
gauge, the LEO Record Ei, is equipped with an integrated data
memory to record pressure and temperature progressions in the
measuring medium. Outside of areas with explosion risks, the
data can be transmitted via an RS485 interface to a PC, for evaluation
with the Logger 4.X software (available free of charge). The
LEO Record Ei can register pressures of up to 1'000 bar with
a total error band of ±0.1 %FS. With a capacitive sensor,
this type is also available for very low measuring ranges starting
from 30 mbar (±0.2 %FS). The application range as per
the ATEX directive is defined by identification marking Ex ia
IIC T4.
Featuring accuracy of up to 0.01 % FS, the LEX 1
Ei electronic pressure gauge is a genuine reference and precision
measuring instrument that has been specifically equipped with
a 5-digit display for calibration and testing purposes. Pressure
measurement ranges of between -1 bar and 1000 bar are available.
The LEX 1 Ei also offers a min/max memory and a digital interface
to generate PC protocols. The application range as per the ATEX
directive is defined by identification marking Ex ia IIC T6.
Features that are shared by all Keller digital pressure gauges
include simple parameterisation and operation with only two buttons.
The pressure display can be shown in various physical units that
can be selected freely.
April 2018
