Campbell Scientific HMP50 User Manual
HMP50 Temperature and
Relative Humidity Probe
Revision: 10/09
Copyright © 1995-2009
Campbell Scientific, Inc.
Warranty and Assistance
The HMP50 TEMPERATURE AND RELATIVE HUMIDITY PROBE is
warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in
materials and workmanship under normal use and service for twelve (12)
months from date of shipment unless specified otherwise. Batteries have no
warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is
limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option)
defective products. The customer shall assume all costs of removing,
reinstalling, and shipping defective products to CAMPBELL SCIENTIFIC,
INC. CAMPBELL SCIENTIFIC, INC. will return such products by surface
carrier prepaid. This warranty shall not apply to any CAMPBELL
SCIENTIFIC, INC. products which have been subjected to modification,
misuse, neglect, accidents of nature, or shipping damage. This warranty is in
lieu of all other warranties, expressed or implied, including warranties of
merchantability or fitness for a particular purpose. CAMPBELL SCIENTIFIC,
INC. is not liable for special, indirect, incidental, or consequential damages.
Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle
repairs for customers within their territories. Please visit
www.campbellsci.com to determine which Campbell Scientific company
serves your country.
To obtain a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone (435) 753-2342. After an applications engineer
determines the nature of the problem, an RMA number will be issued. Please
write this number clearly on the outside of the shipping container.
CAMPBELL SCIENTIFIC's shipping address is:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
For all returns, the customer must fill out a “Declaration of Hazardous Material
and Decontamination” form and comply with the requirements specified in it.
The form is available from our website at
completed form must be either emailed to repair@campbellsci.com
435-750-9579. Campbell Scientific will not process any returns until we
receive this form. If the form is not received within three days of product
receipt or is incomplete, the product will be returned to the customer at the
customer’s expense. Campbell Scientific reserves the right to refuse service on
products that were exposed to contaminants that may cause health or safety
concerns for our employees.
www.campbellsci.com/repair
. A
or faxed to
HMP50 Table of Contents
PDF viewers note: These page numbers refer to the printed version of this document. Use
the Adobe Acrobat® bookmarks tab for links to specific sections.
1. General .........................................................................1
2. Specifications ..............................................................1
2.1 Temperature Sensor..................................................................................2
2.2 Relative Humidity Sensor .........................................................................2
3. Installation....................................................................3
3.1 Siting.........................................................................................................3
3.2 Mounting and Assembly...........................................................................3
4. Wiring............................................................................6
5. Example Programs......................................................6
5.1 Example for CR1000................................................................................7
5.2 Example for CR10X.................................................................................8
6. Long Lead Lengths......................................................9
7. Absolute Humidity.......................................................9
7.1 CR1000 Vapor Pressure Example..........................................................10
7.2 Sample CR10(X) Program that Computes Vapor Pressure and Saturation
Vapor Pressure...................................................................................11
8. Maintenance...............................................................12
8.1 Procedure for Removing RH Chip .........................................................13
9. References .................................................................13
Figures
1. HMP50 as Shipped..................................................................................... 4
2. HMP50 and 41303-5A Radiation Shield on a Tripod Mast .......................4
3. HMP50 and 41303-5A Radiation Shield on a CM202 Crossarm...............5
4. HMP50 and 41303-5A Radiation Shield....................................................5
5. HMP50 Wiring...........................................................................................6
6. Exploded View of HMP50 (as shipped)...................................................13
i
HMP50 Table of Contents
Tables
1. Recommended Lead Lengths..................................................................... 1
2. Datalogger Connections.............................................................................6
3. Calibration for Temperature....................................................................... 7
4. Calibration for Relative Humidity ............................................................. 7
5. Wiring for CR1000 and CR10X Examples................................................ 7
6. Wiring for Vapor Pressure Examples ...................................................... 10
ii
HMP50 Temperature and Relative
Humidity Probe
1. General
The HMP50 Temperature and Relative Humidity probe contains a Platinum
Resistance Temperature detector (PRT) and a Vaisala INTERCAP® capacitive
relative humidity sensor.
The -L option on the model HMP50 Temperature and Relative Humidity probe
(HMP50-L) indicates that the cable length is user specified. Lead length is
specified when the sensor is ordered. Table 1 gives the recommended lead
length. This manual refers to the sensor as the HMP50.
TABLE 1. Recommended Lead Lengths
2 m Height Atop a tripod or tower via a 2 ft crossarm such as the CM202
Mast/Leg CM202 CM6 CM10 CM110 CM115 CM120 UT10 UT20 UT30
9' 11' 11' 14' 14' 19' 24' 14' 24' 37'
Note: Add two feet to the cable length if you are mounting the enclosure on the leg base of a light-weight tripod.
2. Specifications
Operating Temperature: -40°C to +60°C
Storage Temperature: -40°C to +80°C
Probe Length: 7.1 cm (2.8 in.)
Probe Body Diameter: 1.2 cm (0.47 in.)
Filter: 0.2 μm Teflon membrane
Filter Diameter: 1.2 cm (0.47 in.)
Housing Material: chrome-coated aluminum and
chrome-coated ABS plastic
Power Consumption: <2 mA
Supply Voltage: 7 to 28 VDC
Settling Time after power is switched on: 1 second
1
HMP50 Temperature and Relative Humidity Probe
2.1 Temperature Sensor
Sensor: 1000 Ω PRT, DIN 43760B
Temperature Measurement Range: -40°C to +60°C
Temperature Output Signal range: 0 to 1.0 VDC
Temperature Accuracy:
1.6
1.2
0.8
0.4
o
( C)
0
-0.4
Error
-0.8
-1.2
-1.6
-20-40 0
2.2 Relative Humidity Sensor
20 40 60
Temperature( C)
o
Sensor: INTERCAP®
Relative Humidity Measurement Range: 0 to 98% non-condensing
RH Output Signal Range: 0 to 1.0 VDC
Accuracy at 20°C
±3% RH (0 to 90% Relative Humidity)
±5% RH (90 to 98% Relative Humidity)
Temperature Dependence of Relative Humidity Measurement:
1.5
1.0
o
0.5
C
0
-0.5
( %RH/ )
-1.0
-1.5
Temperature Dependence
10 20 30 40 50 60 70 80 90 100
o
60 C
-40 C
RH (%)
o
Typical Long Term Stability: Better than 1% RH per year
Response Time (at 20°C, 90% response to a steep change in humidity):
15 seconds with membrane filter
2
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