RETIRED ›
This product is no longer available and has been replaced by: EE181-L. Some accessories, replacement parts, or services may still be available.
HMP45C-L Temperature and Relative Humidity Probe
Services Available
Repair No
Calibration Yes
Free Support No

Overview

The HMP45C is a rugged, accurate temperature and relative humidity probe. It measures relative humidity over the range of 0 to 100% RH and temperature over the range of -40° to +60°C. This probe is suitable for long-term, unattended monitoring, and is compatible with all Campbell Scientific dataloggers.

Read More

Benefits and Features

  • Well-suited for long-term, unattended applications
  • Accurate and rugged
  • Mounts to a tripod or tower mast, crossarm, or user-supplied pole
  • 13367 Sensor Head available to facilitate recalibration
  • Compatible with most Campbell Scientific data loggers

Images

Technical Description

The HMP45C probe uses a HUMICAP capacitive polymer H chip to measure relative humidity and a PRT to measure temperature. Yearly HMP45C recalibrations are recommended.

To reduce the current drain, power can be supplied to the HMP45C only during measurement when the sensor is connected to the datalogger’s switched 12 V terminal. Dataloggers that do not have a switched 12 V terminal, such as the CR510 or CR7, can use the SW12V switched 12 V device to switch power to the sensor only during measurement.

Specifications

Supply Voltage 12 Vdc nominal (typically powered by data logger)
Current Drain ≤ 4 mA (active)
Cable Diameter 0.8 cm (0.3 in.)
Sensor Diameter 2.5 cm (1 in.)
Sensor Length 25.4 cm (10 in.)
Weight 0.27 kg (0.6 lb)

Relative Humidity

Sensor Vaisala’s HUMICAP H-chip
Measurement Range 0.8% to 100% RH (non-condensing)
Output Signal Range 0.008 to 1 Vdc
Accuracy at 20°C (against factory reference) ±1% RH
Accuracy at 20°C (field-calibrated against references)
  • ±2% (0% to 90% RH)
  • ±3% (90% to 100% RH)
Temperature Dependence ±0.05% RH/°C
Long-Term Stability Typically, better than 1% RH per year
Response Time 15 s with membrane filter (at 20°C, 90% response)
Settling Time 500 ms

Temperature

Temperature Sensor 1000 ohm Platinum Resistance Thermometer
Measurement Range -39.2° to +60°C
Output Signal Range 0.008 to 1.0 V
Accuracy at -40°C ±0.5°C
Accuracy at -20°C ±0.4°C
Accuracy at 0°C ±0.3°C
Accuracy at 20°C ±0.2°C
Accuracy at 40°C ±0.3°C
Accuracy at 60°C ±0.4°C

Compatibility

Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.

Dataloggers

Product Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR3000 (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR800 (retired)
CR850 (retired)
CR9000 (retired)
CR9000X (retired)

Additional Compatibility Information

Mounting

The HMP45C should be housed in a 41003-5 10-plate naturally-aspirated solar radiation shield. The 27251 hex plug is required to mount the HMP45C in the 41003-5. At one time, this hex plug was shipped with the radiation shield but it no longer is. The41003-5 mounts to a tripod or tower mast, crossarm, or user-supplied pole.


Related FAQs

Number of FAQs related to HMP45C-L: 1

  1. The HMP60-L (with the Campbell Scientific cable) cannot be used with the 41003-5 10-Plate Radiation Shield without the use of additional hardware. For more information, refer to the Compatibility tab of the HMP60-L product page. The standard radiation shield for the HMP60-L is the 41303-5A.

Case Studies

Texas: Water Conservation
The city of Frisco, Texas, sits in an area that experienced severe drought from about......read more
Washington AgWeatherNet
Washington State University’s AgWeatherNet (AWN) is a large automated network composed almost entirely of Campbell......read more
Alaska: Eddy Covariance
Scientists and land-use managers have long recognized the importance of forest lands for their role......read more
West Texas Mesonet
The West Texas Mesonet (WTM) project was initiated by Texas Tech University in 1999 to......read more
Israel: Marine Meteorology on the Red Sea
The northern head of the Gulf of Eilat is an ecologically unique marine system of......read more
Bucknell University: Weather Station
The Geography Department at Bucknell University has implemented a weather station to obtain meteorological data......read more
Utah Energy Industry: Air Quality and Met Monitoring
The past few years have seen a scramble within the power industry to use more......read more
New Jersey: Water-Resource Management and Weather Monitoring
When the South Jersey Resource Conservation and Development Council (SJRC&D) was challenged to provide a......read more