5.3 Transmitter
A transmitter of the type TTH300 made
by ABB is used as a standard for evaluat-
ing the signal measured by the T probe
(the thermal voltage). The transmitter is
a freely programmable unit that converts
the measured signals of thermocouples
and of resistance thermo meters into a
standard potential-free 4-20 mA signal.
The transmitter is integrated into the ter-
minal box on the probe carrier already in
the factory where it is also connected to
the sensor lines.
Based on product-dependent tolerances
in the manufacture of pallaplat, the val-
ues of the characteristic may slightly
deviate between batches. Therefore, the
batch-specific characteristic is measured
after the production of each batch. Dur-
ing the internal acceptance test in the
factory, the TTH300 is parameterized
with this batch-specific characteristic.
The characteristic has a total of 32 inter-
mediate points. The values of the char-
acteristic are indicated in the test report
that is attached to each probe supplied.
The transmitter is programmed using the
“Smart Vision” firmware. The TTH300
is also equipped with a HART interface
which allows for programming of the
transmitter on location.
For more details concerning the trans-
mitter, please refer to the documentation
that is attached to each probe supplied.
As a rule, it is possible to use other types
or makes instead of the TTH300. How-
ever, the following conditions must be
observed in this case:
n The transmitter must be freely pro-
grammable and must be programmed
with the batch-specific pallaplat char-
acteristic. Third-party transmitters
cannot be programmed by Pfaudler
because we do not have the hardware
and software necessary for that pur-
pose. However, Pfaudler will support
you with the programming of third-
party transmitters.
n The transmitter must have a reference
location.
n Pfaudler cannot provide any binding
information concerning the accuracy
of the measuring system as a whole if
third-party transmitters are used.
If the ambient temperature in the sur-
roundings of the transmitter is exces-
sively high on location (refer to Sect. 5.4),
the transmitter must be installed next to
the probe carrier in an area in which the
temperature is lower. A pallaplat com-
pensation line must be used to connect
the terminal box on the probe carrier
to the transmitter. Suitable compensat-
ing lines are available from Pfaudler
(part no. 029034).
m The T probe must in all cases
be operated in conjunction with a
freely programmable transmitter,
otherwise, the temperature mea-
surement will not be correct.
© Pfaudler GmbH · OI 302-8 e
6
Temperature probes type T/TW
© Pfaudler GmbH 6
Temperature probes type T/TW
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