Pressure Transmitters
with Mathematical Compensation
Keller has launched the Series 33 X and 35 X of pressure transmitters.
A floating measurement cell, totally digital signal processing,
compensation with mathematical accuracy and a highly dynamic
microprocessor - these assets produce reference accuracies of
up to 0,05 %FS error bandwidth.
The floating piezoresistive sensor element is free of outside
influence from mechanical and thermal forces at the pressure
connection. The A/D converter in the signal processor operates
with a resolution of 16 bits (0,002 US), using the signals from
the pressure sensor and the integrated temperature sensor to
calculate accurate compensated measurement values in just a few
milliseconds.
The
transmitter's analogue output is updated at least 400 times per
second, with overall accuracy of 0,05 %FS (including temperature
influence in the 10 °C...40 °C range). As an option,
precision of 0,01 %FS in the same temperature range is available,
in relation to the reference values of primary standards (accuracy:
0,025 7~).
In the typical
process temperature range of -10 °C...+80 °C (an interval
of 90 degrees Kelvin), the 33 X and 35 X pressure transmitters
supply their digital measured values with a total error band
of 0,1 %FS. The digital output permits functions such as direct
display of measured pressure values on a laptop or PC, and serial
networking for up to 128 transmitters.
Depending on
the plug type and the number of contacts available, the transmitters
provide a digital output (RS485) as well as an analogue current
or voltage output, e.g. 0...10 V (3-wire); 4...20 mA (2-wire).
Measurement ranges
between 0,8 bar and 1000 bar can be supplied for absolute, gauge,
and differential pressures. The pressure port can be a threaded
connection 33 X, or a frontflush diaphragm 35 X. Thanks to the
digital interface (RS485), the analog signal span and zero can
be adjusted across the whole of basic measurement range, to suit
specific applications.
Two PC programs
are available free of charge for Series 30 X precision transmitters:
PROG30 is used to parameterise the instruments locally and to
record individual measured values, etc. READ30 allows users to
assemble entire setups for recording measured values, including
a graphic signal display for up to sixteen transmitters.
Series 33 X typically
offers a pressure port of G1/4"male or G1/2" male thread
as the process connection. Series 35 X adds a transmitter with
a flush front diaphragm to the product range; 36 X W is the depth
/ water level transmitter version.
Users can choose
from three electrical plug connectors. These are easily changed
over when the instruments are used in different environments.
If protection class IP68 is required (standard for the 36 X W
depth sensor), a version with a cable connection is also available.
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May 2012
