Campbell HMP60 Instruction Manual

INSTRUCTION MANUAL

HMP60 Temperature and

Copyright © 1995- 2015

Campbell Scientific, Inc.

Relative Humidity Probe

Revision: 6/15

Limited Warranty

“Products manufactured by CSI are warranted by CSI to be free from defects in
materials and workmanship under normal use and service for twelve months
from the date of shipment unless otherwise specified in the corresponding
product manual. (Product manuals are available for review online at

www.campbellsci.com.) Products not manufactured by CSI, but that are resold

by CSI, are warranted only to the limits extended by the original manufacturer.
Batteries, fine-wire thermocouples, desiccant, and other consumables have no
warranty. CSI’s obligation under this warranty is limited to repairing or
replacing (at CSI’s option) defective Products, which shall be the sole and
exclusive remedy under this warranty. The Customer assumes all costs of
removing, reinstalling, and shipping defective Products to CSI. CSI will return
such Products by surface carrier prepaid within the continental United States of
America. To all other locations, CSI will return such Products best way CIP
(port of entry) per Incoterms ® 2010. This warranty shall not apply to any
Products which have been subjected to modification, misuse, neglect, improper
service, accidents of nature, or shipping damage. This warranty is in lieu of all
other warranties, expressed or implied. The warranty for installation services
performed by CSI such as programming to customer specifications, electrical
connections to Products manufactured by CSI, and Product specific training, is
part of CSI's product warranty. CSI EXPRESSLY DISCLAIMS AND

EXCLUDES ANY IMPLIED WARRANTIES OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE. CSI hereby disclaims,
to the fullest extent allowed by applicable law, any and all warranties and
conditions with respect to the Products, whether express, implied or
statutory, other than those expressly provided herein.”

Assistance

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 [phone]. After an application 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 “Statement of Product Cleanliness
and Decontamination” form and comply with the requirements specified in it.
The form is available from our web site at www.campbellsci.com/repair. A
completed form must be either emailed to [e-mail] or faxed to
[phone]. Campbell Scientific is unable to 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.

Precautions

DANGER — MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON OR AROUND

TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS, ENCLOSURES,
ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE, INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS,

TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS
INJURY, PROPERTY DAMAGE, AND PRODUCT FAILURE. TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS.
CHECK WITH YOUR ORGANIZATION'S SAFETY COORDINATOR (OR POLICY) FOR PROCEDURES AND REQUIRED PROTECTIVE
EQUIPMENT PRIOR TO PERFORMING ANY WORK.

Use tripods, towers, and attachments to tripods and towers only for purposes for which they are designed. Do not exceed design
limits. Be familiar and comply with all instructions provided in product manuals. Manuals are available at www.campbellsci.com or
by telephoning [phone] (USA). You are responsible for conformance with governing codes and regulations, including safety
regulations, and the integrity and location of structures or land to which towers, tripods, and any attachments are attached. Installation
sites should be evaluated and approved by a qualified engineer. If questions or concerns arise regarding installation, use, or
maintenance of tripods, towers, attachments, or electrical connections, consult with a licensed and qualified engineer or electrician.

General

• Prior to performing site or installation work, obtain required approvals and permits. Comply

with all governing structure-height regulations, such as those of the FAA in the USA.

• Use only qualified personnel for installation, use, and maintenance of tripods and towers, and

any attachments to tripods and towers. The use of licensed and qualified contractors is highly
recommended.

• Read all applicable instructions carefully and understand procedures thoroughly before

beginning work.

• Wear a hardhat and eye protection, and take other appropriate safety precautions while

working on or around tripods and towers.

• Do not climb tripods or towers at any time, and prohibit climbing by other persons. Take

reasonable precautions to secure tripod and tower sites from trespassers.

• Use only manufacturer recommended parts, materials, and tools.

Utility and Electrical

• You can be killed or sustain serious bodily injury if the tripod, tower, or attachments you are

installing, constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with
overhead or underground utility lines.

• Maintain a distance of at least one-and-one-half times structure height, 20 feet, or the distance

required by applicable law, whichever is greater, between overhead utility lines and the
structure (tripod, tower, attachments, or tools).

• Prior to performing site or installation work, inform all utility companies and have all

underground utilities marked.

• Comply with all electrical codes. Electrical equipment and related grounding devices should

be installed by a licensed and qualified electrician.

Elevated Work and Weather

• Exercise extreme caution when performing elevated work.

• Use appropriate equipment and safety practices.

• During installation and maintenance, keep tower and tripod sites clear of un-trained or non-

essential personnel. Take precautions to prevent elevated tools and objects from dropping.

• Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.

Maintenance

• Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks,

frayed cables, loose cable clamps, cable tightness, etc. and take necessary corrective actions.

• Periodically (at least yearly) check electrical ground connections.

WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL SCIENTIFIC PRODUCTS,
THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER INSTALLATION, USE, OR
MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS,
ENCLOSURES, ANTENNAS, ETC.

Table of Contents

PDF viewers: These page numbers refer to the printed version of this document. Use the
PDF reader bookmarks tab for links to specific sections.

1. Introduction ................................................................. 1

2. Cautionary Statements ............................................... 1

3. Initial Inspection ......................................................... 1

4. Quickstart .................................................................... 2

5. Overview ...................................................................... 4

6. Specifications ............................................................. 4

6.1 Temperature Sensor ............................................................................. 5

6.2 Relative Humidity Sensor .................................................................... 5

7. Installation ................................................................... 5

7.1 Wiring to Datalogger ........................................................................... 6

7.2 Datalogger Programming ..................................................................... 6

7.2.1 VoltSE() Instruction ...................................................................... 7

7.3 Installation............................................................................................ 7

7.3.1 Installation in a 41303-5A or 41303-5B 6-Plate Shield ................ 8

7.3.2 Installation in a RAD06 6-Plate Shield or RAD10 10-Plate

Shield ......................................................................................... 8

7.3.3 Mount the Shield ........................................................................... 9

8. Operation ................................................................... 10

8.1 Measurement ...................................................................................... 10

8.2 Long Lead Lengths ............................................................................ 10

9. Troubleshooting and Maintenance ......................... 10

9.1 Troubleshooting ................................................................................. 10

9.2 Maintenance ....................................................................................... 11

9.2.1 Procedure for Removing RH Chip .............................................. 12

10. Attributions and References .................................... 12

Appendices

Importing Short Cut Code to CRBasic Editor ...... A-1

A.

B. Example Program ................................................... B-1

i

Table of Contents

C. Absolute Humidity .................................................. C-1

C.1 CR1000 Vapor Pressure Example ................................................... C-1

Figures

7-1. HMP60 as shipped .............................................................................. 8

7-2. HMP60 and 41303-5A Radiation Shield ............................................. 8

7-3. HMP60 and 41303-5A Radiation Shield on a tripod mast (left)

and on a CM202 Crossarm (right) ................................................... 9

7-4. HMP60 and RAD06 Radiation Shield on a tripod mast ...................... 9

9-1. Exploded view of HMP60 (as shipped) ............................................. 11

Tables

7-1. Wire Color, Function, and Datalogger Connection ............................. 6

ii

HMP60 Temperature and Relative
Humidity Probe

1. Introduction

The HMP60 probe measures temperature for the range of –40 to 60 °C, and
relative humidity for the range of 0 to 100% RH. It is suitable for long-term,
unattended monitoring, and is compatible with all Campbell Scientific
dataloggers.

For Edlog datalogger support, check the availability of an older manual at

www.campbellsci.com/old-manuals, or contact a Campbell Scientific

application engineer for assistance.

2. Cautionary Statements

• READ AND UNDERSTAND the Precautions section at the front of this

manual.

• When opening the shipping package, do not damage or cut the cable

jacket. If damage to the cable is suspected, consult with a Campbell
Scientific application engineer.

• Although rugged, the HMP60 should be handled as a precision scientific

instrument.

• Remove the yellow cap prior to installation.

• Santoprene

cable, will support combustion in air. It is used because of its resistance to
temperature extremes, moisture, and UV degradation. It is rated as slow
burning when tested according to U.L. 94 H.B. and passes FMVSS302.
However, local fire codes may preclude its use inside buildings.

3. Initial Inspection

• Check the packaging and contents of the shipment. If damage occurred

during transport, immediately file a claim with the carrier. Contact
Campbell Scientific to facilitate repair or replacement.

• Check model information against the shipping documents to ensure the

expected products and the correct lengths of cable are received. Model
numbers are found on each product. On cables and cabled items, the
model number is usually found at the connection end of the cable. Report
any shortages immediately to Campbell Scientific.

®

rubber, which composes the black outer jacket of the 107

• The HMP60 ships with a ResourceDVD.

1

HMP60 Temperature and Relative Humidity Probe

4. Quickstart

Short Cut is an easy way to program your datalogger to measure the HMP60
sensor and assign datalogger wiring terminals. Use the following procedure to
get started.

1. Install Short Cut by clicking on the install file icon. Get the install file

from either www.campbellsci.com, the ResourceDVD, or find it in
installations of LoggerNet, PC200W, PC400, or RTDAQ software.

2. The Short Cut installation should place a shortcut icon on the desktop of

your computer. To open Short Cut, click on this icon.

3. When Short Cut opens, select New Program.

2

HMP60 Temperature and Relative Humidity Probe

4. Select Datalogger Model and Scan Interval (default of 5 seconds is OK

for most applications). Click Next.

5. Under the Available Sensors and Devices list, select the Sensors folder,

then select the Meteorological | Relative Humidity & Temperature sub­folder. Select HMP50/HMP60 Temperature & Relative Humidity

Sensor. Click to move the selection to the Selected device window.
Data defaults to degree Celsius. This can be changed by clicking the Deg
C box and selecting Deg F, for degrees Fahrenheit, or K for Kelvin.

3

HMP60 Temperature and Relative Humidity Probe

6. After selecting the sensor, click at the left of the screen on Wiring

Diagram to see how the sensor is to be wired to the datalogger. The

wiring diagram can be printed out now or after more sensors are added.

7. Select any other sensors you have, and then finish the remaining Short Cut

8. If LoggerNet, PC400, RTDAQ, or PC200W is running on your PC, and the

9. If the sensor is connected to the datalogger, as shown in the wiring

5. Overview

The HMP60 Temperature and Relative Humidity probe contains a Platinum
Resistance Temperature detector (PRT) and a Vaisala INTERCAP
relative humidity sensor. It is suitable for long-term, unattended monitoring.
The humidity chip is field-replaceable, eliminating recalibration downtime.

6. Specifications

steps to complete the program. The remaining steps are outlined in Short
Cut Help, which is accessed by clicking on Help | Contents |

Programming Steps.

PC to datalogger connection is active, you can click Finish in Short Cut
and you will be prompted to send the program just created to the
datalogger.

diagram in step 6, check the output of the sensor in the datalogger support
software data display to make sure it is making reasonable measurements.

®

capacitive

4

Features:

• Field-replaceable humidity chip eliminates recalibration down time

• Compatible with the CWS900-series interfaces, allowing it to be used

in a wireless sensor network

• Compatible with the following CRBasic dataloggers: CR200(X)

series, CR6, CR800 series, CR1000, CR3000, CR5000, CR9000(X)

HMP60 Temperature and Relative Humidity Probe

Operating Temperature: –40 to 60 °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

Body Material: AISI 316 stainless steel
Filter Cap Material: Chrome-coated ABS plastic
Classification: IP65

Power Consumption: 1 mA typical; 5 mA maximum

Supply Voltage: 5 to 28 Vdc

Settling Time after
power is switched on: 1 s

Output Signal Range: 0 to 1 Vdc

6.1 Temperature Sensor

Sensor: 1000 Ω PRT, DIN 43760B

Temperature
Measurement Range: –40 to 60 °C

Temperature Accuracy: ±0.6 °C (–40 to 60 °C)

6.2 Relative Humidity Sensor

Sensor: INTERCAP®

Relative Humidity
Measurement Range: 0 to 100% non-condensing

Accuracy from 0 to 40 °C: ±3% RH over 0 to 90%

±5% RH over 90 to 100%

Accuracy from –40 to 0 °C
and 40 to 60 °C: ±5% RH over 0 to 90%

±7% RH over 90 to 100%

7. Installation

If you are programming your datalogger with Short Cut, skip Section 7.1,
Wiring to Datalogger
Short Cut does this work for you. See Section 4, Quickstart
Cut tutorial.

(p. 6), and Section 7.2, Datalogger Programming (p. 6).

(p. 2), for a Short

5

HMP60 Temperature and Relative Humidity Probe

TABLE 7-1. Wire Color, Function, and Datalogger Connection

⏚

CAUTION

NOTE

7.1 Wiring to Datalogger

Always connect the blue wire to the datalogger first, followed
by the black, white, and clear wires. Connect the brown
(power) wire last.

Wire

Color

Wire Function

Black Temperature signal

White

Blue

Relative humidity

signal

Power ground and

signal reference

Brown Power

Clear EMF Shield

1

U channels are automatically configured by the measurement instruction.

7.2 Datalogger Programming

Short Cut is the best source for up-to-date datalogger programming code.
Programming code is needed,

• when creating a program for a new datalogger installation

• when adding sensors to an existing datalogger program

Datalogger Connection Terminal

U configured for

single-ended analog input1,

SE (single-ended, analog-voltage input)

U configured for

single-ended analog input, SE

G

12V

(analog ground)

If your data acquisition requirements are simple, you can probably create and
maintain a datalogger program exclusively with Short Cut. If your data
acquisition needs are more complex, the files that Short Cut creates are a great
source for programming code to start a new program or add to an existing
custom program.

Short Cut cannot edit programs after they are imported and edited
in CRBasic Editor.

A Short Cut tutorial is available in Section 4, Quickstart (p. 2). If you wish to
import Short Cut code into CRBasic Editor to create or add to a customized
program, follow the procedure in Appendix A, Importing Short Cut Code to
CRBasic Editor

(p. A-1). Programming basics for CRBasic dataloggers are

provided in the following sections. Complete program examples for select
dataloggers can be found in Appendix B, Example Program

6

(p. B-1).

7.2.1 VoltSE() Instruction

CRBasic dataloggers (CR200(X)-, CR6-, and CR800-series, CR1000, CR3000,
and CR5000) measure the temperature and relative humidity signals from the
HMP60 using VoltSE() measurement instructions.

The probe output scale is 0 to 1000 millivolts for the temperature range of
–40 to 60 °C and for the relative humidity range of 0 to 100%.

VoltSE(Dest, Reps, Range, SEChan, MeasOff, SettlingTime,

Integ/FNotch, Mult, Offset)

Variations:

• Temperature reported as °C — set Mult to 0.1 and Offset to –40

• Temperature reported as °F — set Mult to .18 and Offset to –40

• Humidity reported as a percent — set Mult to 0.1 and Offset to 0

• Humidity reported as a fraction — set Mult to 0.001 and Offset to 0

7.3 Installation

Locate the sensor over an open, level area at least 9 m (EPA) in diameter. The
surface should be covered by short grass or the natural earth surface where
grass does not grow. Sensors should be located at a distance of at least four
times the height of any nearby obstruction and at least 30 m (EPA) from large,
paved areas. Sensors should be protected from thermal radiation and
adequately ventilated.

HMP60 Temperature and Relative Humidity Probe

Standard measurement heights:

1.5 m (AASC)

1.25 – 2.0 m (WMO)

2.0 m (EPA)

See Section 10, Attributions and References

(p. 12), for a list of references that

discuss temperature and relative humidity sensors.

When used in the field, the HMP60 must be housed inside a solar radiation
shield. Typically, the 41303-5A or RAD06 six-plate solar radiation shield is
used. The HMP60 is held within the 41303-5A by a mounting clamp
(FIGURE 7-2).

This probe may also be housed in a 41003-5 or RAD10 ten-plate shield.
Additional hardware must be used with the 41003-5. No additional hardware is
required with the RAD10. A 41322 Adapter Plate allows the HMP60 to be
mounted in the lower part of the 41003-5 shield.

The white color of these shields reflects solar radiation, and the louvered
construction allows air to pass freely through, thereby keeping the probe at or
near ambient temperature. The RAD06 and RAD10 use a double-louvered
design that offers improved sensor protection from insect intrusion and driving
rain and snow. In addition, the RAD06 and RAD10 shields have lower self­heating in bright sunlight combined with higher temperatures (> 24 °C (75 °F))
and low wind speeds (< 2 m/s (4.5 mph)), giving a better measurement.

Each of these solar radiation shields attaches to a crossarm, mast, or user­supplied pipe with a 2.5 to 5.3 cm (1.0 to 2.1 in) outer diameter.

7

HMP60 Temperature and Relative Humidity Probe

Yellow Shipping Cap
(remove before
installation)

Tools required for installing a radiation shield to a tripod or tower include:

• 1/2-inch open-end wrench

• small screwdriver provided with datalogger

• small Phillips screwdriver

• UV-resistant cable ties

• small pair of diagonal-cutting pliers

• adjustable wrench with a minimum 1-7/8 inch jaw size

FIGURE 7-1. HMP60 as shipped

7.3.1 Installation in a 41303-5A or 41303-5B 6-Plate Shield

1. Pull off the yellow shipping cap (see FIGURE 7-1).

2. With a small Phillips screwdriver, loosen the plastic split collar at the base

of the shield (reversing the removable portion if necessary) and gently
insert the probe.

3. Tighten the screws on the collar until it firmly grips the probe body (see

FIGURE 7-2).

FIGURE 7-2. HMP60 and 41303-5A Radiation Shield

7.3.2 Installation in a RAD06 6-Plate Shield or RAD10 10-Plate Shield

8

1. Pull off the yellow shipping cap (see FIGURE 7-1).

2. Loosen the nut on the entry gland at the bottom of the shield.

3. Insert the sensor up into the gland as far as it will go. (See FIGURE 7-4.)

4. Using an adjustable wrench, tighten the nut on the gland until the sensor is

held firmly in place. Do not overtighten.

7.3.3 Mount the Shield

CAUTION

1. Attach the radiation shield to the tripod mast, crossarm, or tower leg using

the supplied U-bolt. See FIGURE 7-3 and FIGURE 7-4 for examples of
shield mounting.

2. Route the cable to the datalogger, and secure the cable to the mounting

structure using cable ties.

Failure to secure the cable can lead to breakage of the wires
due to fatigue caused by blowing back and forth in the wind.

HMP60 Temperature and Relative Humidity Probe

FIGURE 7-3. HMP60 and 41303-5A Radiation Shield

on a tripod mast (left) and on a CM202 Crossarm (right)

FIGURE 7-4. HMP60 and RAD06 Radiation Shield on a tripod mast

9

HMP60 Temperature and Relative Humidity Probe

NOTE

8. Operation

8.1 Measurement

The HMP60 Temperature and Relative Humidity Probe uses a Platinum
Resistance Temperature detector (PRT) and a Vaisala INTERCAP
relative humidity sensor.

8.2 Long Lead Lengths

Long lead lengths cause errors in the measured temperature and relative
humidity. The approximate error in temperature and relative humidity is

0.52 °C and 0.52% per 100 feet of cable length, respectively.

When long lead lengths are required and the above errors in temperature and
relative humidity are unacceptable, use the HC2S3 or HMP155A temperature
and humidity probe.

Understanding the following details are not required for the general operation
of the HMP60 with Campbell Scientific’s dataloggers. The signal reference
and the power ground (black) are the same lead in the HMP60. When the
HMP60 temperature and relative humidity are measured, both the signal
reference and power ground are connected to ground at the datalogger. The
signal reference/power ground lead serves as the return path for 12 V. There
will be a voltage drop along this lead because the wire itself has resistance.
The HMP60 draws approximately 2 mA when it is powered. The wire used in
the HMP60 (pn 18159) has resistance of 26.2 Ω/1000 feet. Using Ohm’s law,
the voltage drop (V
by Eq. (1).

®

capacitive

), along the signal reference/power ground lead, is given

d

V
= 2 mA × 26.2Ω 1000 ft⁄ (1)
= 52.4 mV 1000 ft⁄

This voltage drop will raise the apparent temperature and relative humidity
because the difference between the signal and signal reference at the datalogger
has increased by V

.

d

= I ×R

d

9. Troubleshooting and Maintenance

All factory repairs and recalibrations require a returned material
authorization (RMA) and completion of the “Declaration of
Hazardous Material and Decontamination” form. Refer to the

Assistance page at the beginning of this manual for more

information.

9.1 Troubleshooting

Symptom: Relative Humidity is reported as NAN, –9999, or 0%

1. Check that the sensor is wired to the correct analog input channels as

specified by the measurement instructions.

10

2. Verify the voltage range code for the single-ended measurement

Protective Cap
and Filter

Shipping Cap
(remove prior
to installation)

9598 RH Chip

Symptom: Incorrect temperature or relative humidity

1. Verify the multiplier and offset parameters are correct for the desired units

9.2 Maintenance

Check the radiation shield monthly to make sure it is free from dust and debris.
To clean the shield, first remove the sensor. Dismount the shield. Brush all
loose dirt off. If more effort is needed, use warm, soapy water and a soft cloth
or brush to thoroughly clean the shield. Allow the shield to dry before
remounting.

The white screen at the tip of the HMP60 should also be checked for
contaminants.

When installed in close proximity to the ocean or other bodies of salt water
(e.g., Great Salt Lake), a coating of salt (mostly NaCl) may build up on the
radiation shield, sensor, filter and even the chip. NaCl has an affinity for
water. The humidity over a saturated NaCl solution is 75%. A buildup of salt
on the filter or chip will delay or destroy the response to atmospheric humidity.

HMP60 Temperature and Relative Humidity Probe

instruction is correct for the datalogger type.

(see Section 7.2.1, VoltSE() Instruction

(p. 7)).

The filter can be rinsed gently in distilled water. If necessary, the chip can be
removed and rinsed as well (see FIGURE 9-1 and Section 9.2.1, Procedure for
Removing RH Chip

(p. 12)). Do not scratch the silver chip while cleaning. It

might be necessary to repeat rinsing.

FIGURE 9-1. Exploded view of HMP60 (as shipped)

The offset and gain on the HMP60 electronics cannot be adjusted as part of a
recalibration. Replace the RH chip as needed.

11

HMP60 Temperature and Relative Humidity Probe

CAUTION

9.2.1 Procedure for Removing RH Chip

1. Unscrew the protective cap.

2. Hold the plastic sides of the RH chip and unplug it.

To prevent scratching, avoid touching the silver RH chip,
and handle the RH chip with care.

3. Rinse the RH chip or dispose of the old RH chip.

4. Hold the sides of the rinsed or new chip and plug it in.

5. Screw on the protective cap.

10. Attributions and References

Santoprene® is a registered trademark of Exxon Mobile Corporation.

AASC, 1985: The State Climatologist (1985) Publication of the American

Association of State Climatologists: Heights and Exposure Standards for
Sensors on Automated Weather Stations, v. 9, No. 4 October, 1985.
(www.stateclimate.org/publications/state-climatologist/NOAA-NCY­SCBOOKS-SC77097/00000029.pdf)

EPA, 2008: Quality Assurance Handbook for Air Pollution Measurement

Systems, Vol. IV, Meteorological Measurements, Ver. 2.0, EPA-454/B-08­002 (revised 2008).Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711.

Goff, J. A. and S. Gratch, 1946: Low-pressure properties of water from -160°

to 212°F, Trans. Amer. Soc. Heat. Vent. Eng., 51, 125-164.

Lowe, P. R., 1977: An approximating polynomial for the computation of

saturation vapor pressure, J. Appl. Meteor., 16, 100-103.

Meyer, S. J. and K. G. Hubbard, 1992: Nonfederal Automated Weather

Stations and Networks in the United States and Canada: A Preliminary
Survey, Bulletin Am. Meteor. Soc., 73, No. 4, 449-457.

Weiss, A., 1977: Algorithms for the calculation of moist air properties on a

hand calculator, Amer. Soc. Ag. Eng., 20, 1133-1136.

WMO, 2008. Guide to Meteorological Instruments and Methods of

Observation. World Meteorological Organization No. 8, 7th edition,
Geneva, Switzerland. Many of the manuals also include siting information
for relative humidity and temperature sensors.

12

NOTE

Appendix A. Importing Short Cut Code to CRBasic Editor

This tutorial shows:

• How to import a Short Cut program into a program editor for

additional refinement

• How to import a wiring diagram from Short Cut into the comments of

a custom program

Short Cut creates files that can be imported into CRBasic Editor. These files
normally reside in the C:\campbellsci\SCWin folder and have the following
extensions:

• .DEF (wiring and memory usage information)

• .CR6 (CR6 datalogger code)

• .CR2 (CR200(X) datalogger code)

• .CR1 (CR1000 datalogger code)

• .CR8 (CR800 datalogger code)

• .CR3 (CR3000 datalogger code)

• .CR5 (CR5000 datalogger code)

Use the following procedure to import Short Cut code into CRBasic Editor.

1. Create the Short Cut program following the procedure in Section 4,
Quickstart
file name used when saving the Short Cut program.

2. Open CRBasic Editor.

3. Click File | Open. Assuming the default paths were used when Short Cut
was installed, navigate to C:\CampbellSci\SCWin folder. The file of
interest has a “.CR6”, “.CR2”, “.CR1”, “.CR8”, “.CR3”, or “.CR5”
extension, for CR6, CR200(X), CR1000, CR800, CR3000, or CR5000
dataloggers, respectively. Select the file and click Open.

4. Immediately save the file in a folder different from \Campbellsci\SCWin,
or save the file with a different file name.

Once the file is edited with CRBasic Editor, Short Cut can no
longer be used to edit the datalogger program. Change the name
of the program file or move it, or Short Cut may overwrite it next
time it is used.

5. The program can now be edited, saved, and sent to the datalogger.

(p. 2). Finish the program and exit Short Cut. Make note of the

6. Import wiring information to the program by opening the associated .DEF
file. Copy and paste the section beginning with heading “-Wiring for
CRXXX–” into the CRBasic program, usually at the head of the file.
After pasting, edit the information such that a ' character (single quotation

A-1

Appendix A. Importing Short Cut Code to CRBasic Editor

mark) begins each line. This character instructs the datalogger compiler to
ignore the line when compiling the datalogger code.

A-2

Appendix B. Example Program

This example can be used directly with CR800 series and CR1000 dataloggers
and can be modified for use with CR6, CR3000, and CR5000 dataloggers.

'Program measures the HMP60 probe once every 5 seconds and stores the average
‘temperature and a sample of the relative humidity every 60 minutes.

'Wiring Diagram
'==============
'HMP60
'Wire CR1000
'Color Function Terminal
'------ -------- -------­'Black Temperature signal SE1
'White Relative Humidity signal SE2
'Brown Power 12V
'Blue Signal & Power Reference G
'Clear Shield Ground Symbol

Public AirTC
Public RH

DataTable(Temp_RH,True,-1)

DataInterval(0,60,Min,0)
Average(1,AirTC,FP2,False)
Sample(1,RH,FP2)

EndTable

BeginProg

Scan(5,Sec,1,0)
PortSet(9,1) 'Turn on switched 12V
Delay(0,3,Sec) '3-second delay

'HMP50/HMP60 Temperature & Relative Humidity Sensor measurements AirTC and RH

VoltSe(AirTC,1,mV2500,1,0,0,_60Hz,0.1,-40)

VoltSE(RH,1,mV2500,2,0,0,_60Hz,0.1,0)

If RH>100 AND RH<108 Then RH=100

CallTable(Temp_RH)

NextScan

EndProg

B-1

Appendix C. Absolute Humidity

The HMP60 measures the relative humidity. Relative humidity is defined by
the equation below:

RH=

where RH is the relative humidity, e is the vapor pressure in kPa , and es is the
saturation vapor pressure in kPa. The vapor pressure, e, is an absolute measure
of the amount of water vapor in the air and is related to the dew point
temperature. The saturation vapor pressure is the maximum amount of water
vapor that air can hold at a given air temperature. The relationship between
dew point and vapor pressure, and air temperature and saturation vapor
pressure are given by Goff and Gratch (1946), Lowe (1977), and Weiss (1977).

When the air temperature increases, so does the saturation vapor pressure.
Conversely, a decrease in air temperature causes a corresponding decrease in
saturation vapor pressure. It follows then from Eq. (C-1) that a change in air
temperature will change the relative humidity, without causing a change in
absolute humidity.

For example, for an air temperature of 20 °C and a vapor pressure of 1.17 kPa,
the saturation vapor pressure is 2.34 kPa and the relative humidity is 50%. If
the air temperature is increased by 5 °C and no moisture is added or removed
from the air, the saturation vapor pressure increases to 3.17 kPa and the relative
humidity decreases to 36.9%. After the increase in air temperature, there is
more energy available to vaporize the water. However, the actual amount of
water vapor in the air has not changed. Thus, the amount of water vapor in the
air, relative to saturation, has decreased.

e

× 100 (C-1)

e

s

Because of the inverse relationship between relative humidity and air
temperature, finding the mean relative humidity is meaningless. A more useful
quantity is the mean vapor pressure. The mean vapor pressure can be
computed on-line by the datalogger. CRBasic dataloggers use the
VaporPressure() instruction to calculate vapor pressure from temperature and
relative humidity measurements (see Appendix C.1, CR1000 Vapor Pressure
Example

(p. C-1).

C.1 CR1000 Vapor Pressure Example

The VaporPressure() instruction has the following syntax:

VaporPressure(Dest,Temp,RH)

Where:

Dest is the variable in which the results of the instruction will be stored.

Temp is the program variable that contains the value for the temperature sensor.

The temperature measurement must be in degrees Celsius.

RH is the program variable that contains the value for the relative humidity

sensor. The relative humidity measurement must be in percent of RH.

C-1

Appendix C. Absolute Humidity

'Wiring Diagram
'==============
'HMP60
'Wire CR1000
'Color Function Terminal
'------ -------- -------­'Black Temperature signal SE1
'White Relative Humidity signal SE2
'Brown Power 12V
'Blue Signal & Power Reference G
'Clear Shield Ground Symbol

Public AirTC
Public RH
Public VP

DataTable(Table1,True,-1)

DataInterval(0,60,Min,0)
Average(1,AirTC,FP2,0)
Sample(1,RH,FP2)
Average(1,VP, FP2,0)

EndTable

BeginProg

Scan(5,Sec,1,0)
'HMP60 Temperature & Relative Humidity Sensor measurements AirTC and RH:
VoltSE(AirTC,1,mV2500,1,0,0,_60Hz,0.1,-40.0)
VoltSE(RH,1,mV2500,2,0,0,_60Hz,0.1,0)
If (RH>100) AND (RH<108) Then RH=100
VaporPressure(VP,AirTC,RH)
CallTable(Table1)
NextScan

EndProg

C-2

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