Tiny Pressure
Transmitters meet miniaturisation demands
Keller has introduced the compact Series LD pressure transmitters.
According to the company, these tiny transmitters are setting
new trends in OEM applications, as miniaturisation is now becoming
a reality.
In its Series 4 LC ...9 LC pressure transmitters, the special
ASIC for signal processing is fitted directly next to the pressure
sensor, in the same housing, under oil, and with the exclusion
of air. This yields a host of advantages in terms of application:
all the key pressure measurement components are now protected
against the risks from humidity and condensation.
The interior wiring is implemented with short, lightweight bonding
wires, while sintered-in pressure-resistant glass lead-through
feed the transmitter signals out. Together with the high-grade
stainless steel housing, they form a Faraday cage around the
measuring system, acting as feed-through capacitors. This makes
the CiO technology absolutely RFI resistant up to field strengths
of 250V/m and for frequencies of up to 4GHz.
Series 4 LC ...9 LC pressure transmitters offers two output signals:
a ratiometric analogue voltage output and a digital inter-integrated
circuit interface (12C). The ratiometric signal eliminates the
need for an expensive voltage reference in the support electronics
to the A/D converter, with no additional effort and expense for
compensation and calibration. For a voltage supply of S,oV, the
output signal is specified as 0,5 ... 4,5V.
For years, the IBC interface has been regarded as the serial
standard in
embedded systems. Up to 128 OEM transmitters in Series 4 LC ...9
LC can be addressed successively by one I2C master in order to
call up the current pressure and temperature values from the
transmitters (slaves). With an I2C output, the pressure transmitters
can operate with a voltage supply of only 2,7 ... 3,6 VDC, and
they are ready to supply the current measured values 5ms after
switching on. Appropriate ON/OFF operation and low power consumption
make these transmitters ideally suited for mobile applications.
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October 2015
