HMP45C-L
HMP45C-L
End of lifeTemperature and Relative Humidity Probe
No longer available to order
This product is retained for service, documentation, and compatibility information.
Replaced by
- EE181
Air Temperature and Relative Humidity Sensor
- Model:
- HMP45C-L
- Item Number:
- HMP45C-L
- Warranty:
- 1 year
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 data loggers.
Key Advantages
Ideal for long-term, unattended applications
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 data logger’s switched 12 V terminal. Data loggers 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.
Product Notes
Benefits
- 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
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
Other Accessories
(3)SW12V
12 V Power Switch Assembly
The SW12V provides a mechanism for older dataloggers that don't have a switched 12V port to control power to the HMP45C. The SW12V is recommended for applications where the HMP45C will be measured by a CR500, CR510, 21X, CR7, or a CR10 with a silver wiring panel.
History: prior to May 2004, the HMP45C cable included a switching circuit that switched power to the sensor only during measurement, fhus conserving system power. Effective 3 May 2004, the switching circuit was removed from the HMP45C cable. The redesigned HMP45C connects to the datalogger's switched 12 V terminal. Dataloggers that do not have a switched 12 V terminal (i.e., CR500, CR510, 21X, CR10 with a silver wiring panel, or a CR7) can use a SW12V Power Switch Assembly to switch power to the HMP45C.Orderable41003-5
10-Plate Solar Radiation Shield
The 41003-5 provides a 10-plate naturally-aspirated radiation shield that houses one HMP45C probe. Its louvered construction allows air to pass freely through the shield thereby keeping the probe at or near ambient temperature. The 41003-5 attaches to a crossarm, mast, or user-supplied pipe with a 1.0" to 2.1" OD.
OrderableRAD14
14-Plate Solar Radiation Shield
When exposed to sunlight, the HMP45C-L must be housed in a radiation shield. The RAD14 uses a double-louvered design that offers improved sensor protection from driving rain, snow, and insect intrusion. It also has lower self-heating in bright sunlight combined with higher temperatures (> 24°C (~75°F)) and low wind speeds (< 2m/s (~4.5 mph)), providing a better measurement.
Orderable
Ships With
(2)- Adjustment Screwdriver from original mfg
- NIST Traceable Calibration Certificate
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.
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Services Available
- Repair
- No
- Calibration
- Yes
- Free Support
- No