HD2301
- 10 -
V1.7
PROBES AND MEASUREMENTS
The instrument HD2301.0 works by using combined humidity/temperature probes
(temperature with a Pt100 sensor) and with temperature only probes with 4 wire
Pt100, or 2 or 4 wire Pt1000.
The combined humidity/temperature probes are fitted with SICRAM module that acts
as an interface between the sensor on the probe and the instrument. There is a
microprocessor circuit with a permanent memory inside the module that enables the
instrument to recognize the type of probe connected and to read its calibration
information.
The Delta OHM Pt1000 probes are automatically detected while the direct 4 wire Pt100
temperature probe is not automatically detected by the instrument and must be set
up in the Probe type menu item (please see the menu description on previous
chapter).
The probe is detected during turn on, and this cannot be performed when the
instrument is already on, therefore if a probe is connected and the
instrument is on, it is necessary to turn it off and on.
M
EASUREMENT OF RELATIVE HUMIDITY
The humidity probes are "humidity and temperature" combined probes:
•
the humidity sensor is a capacitative type sensor;
•
the temperature sensor is a Pt100.
The instrument measures relative humidity %RH and temperature, and starting from
the fixed barometric pressure value of 1013.25 mbar it calculates the following
resulting quantities:
1.
g/m
3
grams of vapour in a cubic meter of dry air
2.
hPa Partial vapour pressure (hPa)
3.
Td Dew point (°C or °F)
P
ERFORMING THE MEASUREMENT
To perform the measurement, proceed as follows:
1.
introduce the probe in the area of whose parameters you wish to measure.
Caution! Keep the probe far from elements that might interfere with measurement
such as: heat or sources of cooling, walls, air-streams, etc
Avoid temperature drops that might cause condensation.
2.
a reading taken when no heat drop occurs is practically immediate;
NOTE: in conditions involving heat drops, it is necessary to wait until the probes and
their housing have reached a thermal equilibrium in order to prevent heat irradiation
or absorption on the relative humidity sensor which would cause a faulty
measurement.
3.
since temperature affects relative humidity; move the probe like a fan in order to
speed the response time in the presence of heat drops.