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11
4.2
Pt100
TEMPERATURE PROBE
The instrument accepts the input of Platinum temperature probes with resistances of 100Ω (Pt100).
The Pt100 sensors are connected to 4 wires; the excitation current was chosen in order to minimize
the sensor self-heating effects.
All probes with module are calibrated in the factory; no calibration is usually required by the user.
The °C or °F unit of measurement can be chosen using the
UNIT
key.
4.2.1 Temperature measurement
The response time for the measurement of the temperature in
air
is greatly reduced if the air is
moving. If the air is still, stir the probe. Please remember that the response times in any case are
longer than those for liquid measurements.
The temperature measurement by
immersion
is carried out by inserting the probe in the liquid for at
least 60 mm; the sensor is housed in the end part of the probe.
In the temperature measurement by
penetration
the probe tip must be inserted to a depth of at least
60 mm, the sensor is housed in the end part of the probe.
NOTE:
when measuring the temperature on frozen blocks it is convenient to use a mechanical tool
to bore a cavity in which to insert the tip probe.
In order to perform a correct
contact
measurement, the measurement surface must be even and
smooth, and the probe must be perpendicular to the measurement plane.
So as to obtain the correct measurement, the insertion of a drop of oil or heat-conductive
paste between the surface and the probe is useful (do not use water or solvents). This method
also improves the response time.
4.2.2 Connecting the TP47 connector
All probes produced by Delta Ohm are provided with a connector.
The
HD2304
also work with direct 4 wire Pt100 probes manufactured by other producers: for the
instrument connection is prescribed the
TP47
connector to which the probe’s wires should be
welded.
The instructions to connect the Platinum probe to the TP47 module are provided below.
The
TP47
module is supplied complete with fairlead and gasket for 5 mm maximum diameter
cables. Do the following to open the module and connect a probe:
1.
unscrew the fairlead;
2.
extract the gasket;
3.
remove the label using a cutter;
4.
unscrew the ring on the opposite side as illustrated in the figure:
