Electricity + Control March 2015

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ROUND UP TEMPERATURE MEASUREMENT
Reliable temperature
measurement with new
thermowell materials
Taking temperature measurements ranging from
800°C to 1 700 °C there are particularly high demands
on the measuring technology used. Many materials
can only withstand the heat and other process con-
ditions for a limited period. While some processes
involve corrosive gases, other processes can be
abrasive.This is exacerbated by turbulence and other
extreme conditions, whichmake things more difficult
for the component parts of a thermometer, particu-
larly the thermowell. A combination of corrosion and
abrasion is often the root cause of thermowell failure.
At critical measuring points, measurements are
either not taken continuously or the thermocouples
must be replaced quite frequently.These measuring
points increase the workload of the maintenance de-
partments, drive up costs and often difficult to access.
In recent years, materials research has provided us
with many new materials, ranging from new metal
alloys to robust ceramic substances. Endress+Hauser
has examined and tested these new materials, and
found it possible to use some to produce thermow-
ells that withstand extreme process conditions far
longer than previously experienced. Endress+Hauser
has incorporated its research and testing results into
the Omnigrad S TAF high-temperature sensor line.
Given the extensive possibilities of combining the
TAF11, TAF12S, TAF12D,TAF 12Tand TAF16 devices,
the ideal thermocouple can be designed for every
application.
Enquiries: Benjamin Mlangeni.Tel. 011 262 8012 or
email
See what it’s about
VEGA has introduced their PLICSLED universal display module for all point
level sensors.The module is compatible with all sensors in VEGA’s plics family
with relay output.
With this new displaymodule the switching status of a sensor can be read from
a distance, even in strong sunlight. Since external wiring is unnecessary,
the time needed for installation is reduced to a minimum.
Power is supplied via the relay electronics. The second re-
lay output is used to control the switching status display.
Depending on the module version, the switching
status is displayed in the colour combination red-
green or yellow-green. PLICSLED is installed
directly inside the plics sensor housing
giving it protection from dust and
water. The display module can be
ordered directly with the sensor
or, alternatively, as a separate
unit for retrofitting.
Enquiries: Chantal Groom.
Tel. 011 795 3249 or email
.
Loop-powered BL 540 isolator for easiest
20 mA signal transmission
For galvanically isolated 1:1
transmission of 4..20 mA stand-
ard signals, Knick provides the
BL 540 isolator from its low-cost
BasicLine series. By reliably
decoupling the field and con-
trol levels, the device prevents
system malfunctions.
At a low 1,7 V voltage drop,
the device needs no auxiliary
power supply but can be pow-
ered through the loop – this
results in the additional advan-
tage of a much reduced wiring
effort.
The isolator features a 0,2%
full scale accuracy. One and
two-channel devices are avail-
able in a 6 mm DIN rail hous-
ing. BL 540 isolators are CE-
compliant and UL-certified.
Knick pro-vides a three-year warranty for the devices. Strictly concentrating on
basic functions, leaving all extras aside, Knick has tailored BasicLine devices
to mechanical engineering companies that need precise and reliable yet cost-
optimized isolators for large-scale applications.
Not-withstanding the attractive price scheme, the devices feature Knick’s
characteristic high level of manufacturing quality and precision as well as com-
plete galvanic isolation. BasicLine com-prises transducers for all major control
cabinet requirements.
Mecosa is the sole agent for Knick ElektronischeMessgeräte in SouthernAfrica.
. 011 257-6100 or email
Electricity+Control March ‘15 44