HMP45C-L

Temperature and Relative Humidity Probe

The HMP45C is a rugged, accurate temperature/RH probe manufactured by Vaisala Inc. The probe uses a HUMICAP capacitive polymer H chip to measure relative humidity over the 0 to 100% RH range. A PRT measures temperature over the -40° to +60°C range.

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.Yearly HMP45C recalibrations are recommended.

Features

Temperature measurement uses PRT
RH measurement uses capacitive RH chip
41003-5 radiation shield recommended when exposed to sunlight
Based on Vaisala HMP-series sensors
13367 Sensor Head available to facilitate recalibration
A HMP45C housed in a 41003-5 can be mounted to a mast or crossarm

Specifications

Supply Voltage: 12 Vdc nominal (typically powered by datalogger)
Current Consumption: ≤4 mA (active)

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
- Field-Calibrated Against References: ±2% (0% to 90% range);
  ±3% (90% to 100% range)
Temperature Dependence: ±0.05% RH/°C
Long-Term Stability: Typically, better than 1% RH per year
Response Time: 15 seconds with membrane filter (at 20°C, 90% response)
Settling Time: 500 milliseconds