RETIRED ›
This product is no longer available and has been replaced by: HC2S3-L. Some accessories, replacement parts, or services may still be available.
Accurate, Reliable
Ideal for long-term, unattended applications
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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.

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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 all Campbell Scientific dataloggers (including the CR200(X) series)

The "-L" on a product model indicates that the cable length is specified at the time of order.

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Detailed 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 datalogger)
  • Current Drain: ≤4 mA (active)
  • Sensor Diameter: 2.5 cm (1 in.)
  • Sensor Length: 25.4 cm (10 in.)
  • Cable Diameter: 0.8 cm (0.3 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:
    ±0.5°C (-40°C),
    ±0.4°C (-20°C),
    ±0.3°C (0°C),
    ±0.2°C (20°C),
    ±0.3°C (40°C),
    ±0.4°C (60°C)

Compatibility

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.

Datalogger Considerations

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR9000X

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR9000 CR7X CR5000

Frequently Asked Questions

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 information on the HMP60-L product page. The standard radiation shield for the HMP60-L is the 41303-5A.

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