Specifications

93
HMP 45A & HMP 45D Relative Humidity and
Temperature Probes; Solar Radiation Shield
VERSATILE PROBES
The HMP 45A and HMP 45D humidity and tempera-
ture probes are designed for a wide range of instru-
mentation e.g. recorders, data loggers, laboratory
equipment and weather stations.* They interface
easily and are simple to service.
RELIABLE PERFORMANCE IN DEMANDING
ENVIRONMENTS
The HMP 45A and HMP 45D provide up to 100% RH
measurement with high accuracy. Both feature
Vaisalas HUMICAP
®
180 sensor, one of the most
reliable sensors on the market. The sensor can be
used in a wide range of environments, has high
accuracy, negligible hysteresis and excellent long-
term stability - even in very high humidities. It is
insensitive to dust and tolerant to most chemicals.
NEW FEATURES
Field calibration is easy with one or two references.
The probe head containing the sensor and electron-
ics can be quickly removed from the probe body, a
replacement installed and the measurements contin-
ued while the other sensor head is calibrated in a
laboratory. If necessary, the humidity and tempera-
ture readings in the HMP 45A can be checked with
Vaisalas HMI 41 humidity indicator on site. Routine
checks and calibrations can be made without inter-
rupting measurements for long periods of time.
The combined performance of the HUMICAP
®
180
sensor and improved NEMA 4 protected probe
enables you to make accurate and repeatable
humidity and temperature measurements with
confidence. These probes can be operated from a
wide range of supply voltages and have low power
consumption. Combine these features with the
probes wide temperature range, temperature
compensation and full-scale humidity range and you
have a versatile solution for many applications.
SHIELD PROVIDES SENSOR PROTECTION
Vaisala also offers the 2212 HM shield to protect the
humidity and temperature sensors from solar radia-
tion and precipitation. It provides excellent ventila-
tion while blocking direct and reflected solar radia-
tion. The 2212 HMs flexible fastening system makes
probe installation simple, and an offset U-bolt makes
mounting equally as easy.
*The HMP 45A/D is an excellent solution for measuring
humidity in weather stations. However, the HMP 243, with
warmed sensor head, is a better solution if condensation
continuously disturbs measurement.
2212 HM shield provides protection
from solar radiation and precipitation.
HMP 45A & HMP 45D humidity
and temperature probes for
meteorological applications
provide EMI/RF protection.