Campbell HygroVUE 5 User manual

Revision: 11/2022
Copyright © 2019– 2022
Campbell Scientific, Inc.

Table of contents
1. Introduction 1
2. Precautions 1
3. Initial inspection 1
4. QuickStart 2
5. Overview 5
6. Specifications 5
6.1 Temperature measurement 6
6.2 Relative humidity measurement 6
7. Installation 7
7.1 Wiring to data logger 7
7.2 Data logger programming 8
7.3 CRBasic programming 8
7.4 Siting 9
7.4.1 Installation in a RAD06 radiation shield 10
7.4.2 Mount the shield 11
8. Operation 12
8.1 Sensor measurement 12
8.2 Measurements in programs with fast scan rates 14
8.3 Long cables 14
8.4 Power conservation 15
8.5 Measuring multiple SDI-12 sensors 15
9. Troubleshooting and maintenance 15
9.1 Troubleshooting 16
9.2 Maintenance 16
9.3 Calibration 17
9.4 Sensor element replacement 17
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10. Attributions and references 19
Appendix A. Importing Short Cut code into CRBasic Editor 21
Appendix B. CRBasic example program 22
Appendix C. Environmental performance 24
C.1 Exposure to pollutants 24
C.2 Operating range of the RH element 24
C.3 Measurement below 0 °C 25
Appendix D. SDI-12 sensor support 26
D.1 SDI-12 command basics 26
D.1.1 Acknowledge active command (a!) 27
D.1.2 Send identification command (al!) 27
D.1.3 Start verification command (aV!) 28
D.1.4 Address query command (?!) 28
D.1.5 Change address command (aAb!) 28
D.1.6 Start measurement commands (aM!) 29
D.1.7 Start concurrent measurement commands (aC!) 29
D.1.8 Start measurement commands with cyclic redundancy check (aMC! and aCC!) 31
D.1.9 Stopping a measurement command 31
D.1.10 Send data command (aD0! … aD9!) 31
D.1.11 Continuous measurement command (aR0! … aR9!) 32
D.2 References 32
D.3 SDI-12 transparent mode 32
D.3.1 Changing an SDI-12 address 33
Appendix E. Sensor element calibration 36
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1. Introduction
The HygroVUE™5 Temperature and Relative Humidity Sensor is designed for general
meteorological and environmental applications. It is the entry level sensor in the HygroVUE line
of Relative Humidity and Temperature sensors. The HygroVUE sensors feature a low
maintenance design with a highly stable and accurate replaceable RH chip that will lower the
total cost of deployment throughout a network. The HygroVUE 5 uses the SDI-12
communications protocol to communicate with any SDI-12 recorder, simplifying wiring and
programming.
2. Precautions
lREAD AND UNDERSTAND the Safety section at the back of this manual.
lWhen opening the shipping package, do not damage or cut the cable jacket. If damage to
the cable is suspected, consult with a Campbell Scientific support engineer.
lAlthough rugged, the HygroVUE 5 should be handled as a precision scientific instrument.
3. Initial inspection
lCheck 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.
lCheck 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.
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4. QuickStart
A video that describes data logger programming using Short Cut is available at:
www.campbellsci.com/videos/cr1000x-data logger-getting-started-program-part-3 .Short
Cut is an easy way to program your data logger to measure the sensor and assign data logger
wiring terminals. Short Cut is available as a download on www.campbellsci.com . It is included
in installations of LoggerNet,RTDAQ, and PC400.
The following procedure also shows using Short Cut to program the sensor.
1. Open Short Cut and click Create New Program.
2. Double-click the data logger model.
3. In the Available Sensors and Devices box, type HygroVUE5 or locate the sensor in the
Sensors >Meteorological >Relative Humidity & Temperature folder. Double-click
HygroVUE5/HygroVUE10 Temperature & Relative Humidity Sensor. Temperature units
default to degrees Celsius. This can be changed by clicking the Deg C box and selecting
Deg F, for degrees Fahrenheit, or Kfor Kelvin. SDI-12 Address defaults to 0. Enter the
correct SDI-12 Address for the HygroVUE 5 if it has been changed from the factory-set
default value.
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4. Click the Wiring tab to see how the sensor is to be wired to the data logger. The default
control terminal for SDI-12 is C1. To change to another terminal, click the terminal name
and select another terminal. Click OK after wiring the sensor.
5. Repeat steps three and four for other sensors you want to measure. Click Next.
6. In Output Setup, type the scan rate (5 seconds or longer), meaningful table names, and the
Data Output Storage Interval. Click Next.
NOTE:
Making measurements from the HygroVUE 5 more frequently than 5 seconds can result
in small additional errors due to self-heating of the element. If the main scan rate needs
to be faster than this, please read Sensor measurement (p. 12) and Measurements in
programs with fast scan rates (p. 14) about alternate programming techniques.
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7. Select the measurement and its associated output option.
8. Click Finish and save the program. Send the program just created to the data logger if the
data logger is connected to the computer.
9. If the sensor is connected to the data logger, check the output of the sensor in the data
display in LoggerNet,RTDAQ, or PC400 to make sure it is making reasonable
measurements.
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5. Overview
The HygroVUE 5 sensor uses a single-chip element that incorporates both a temperature and an
RH sensor. Each element is individually calibrated with the calibration corrections stored on the
chip. The element is easily changed in the field, reducing downtime and calibration costs.
Electronics within the HygroVUE 5 control the measurement made by the sensor element, apply
temperature and linearization corrections to the readings, and present the data via SDI-12 to a
data logger.
A stainless steel mesh filter minimizes the effects of dust and dirt on the sensor while allowing air
exchange around the sensor element and reducing the chances of condensation remaining
inside the filter cap. A small PTFE membrane filter is bonded to the surface of the element which
prevents any finer dust or mold from directly influencing the measurement.
The sensor housing is designed to withstand permanent exposure to weather and to fit into a
range of radiation shields, including compact shields.
6. Specifications
Compatibility: Fully SDI-12 V1.3-compliant digital output (verified with an SDI-12
Verifier (www.sdi-12-verifier.com ).
Compatible with SDI-12 V1.4 recorders including Campbell
Scientific CR6, CR3000, CR1000X, CR800-series, CR300-series, and
CR1000 data loggers
Sensor element: Sensirion SHT35 derivative
Calibration traceability: NIST and NPL standards. See Sensor element calibration (p. 36)
for details of calibration traceability.
Supply voltage: 7 to 28 VDC
Current consumption: 50 µA quiescent, typical
0.6 mA during 0.5 s measurement typical
Warm-up time: Sensor normally powered all the time, if power is switched allow
1.8 s for sensor power-up.
Diameter: 12.5 mm (0.49 in) at sensor tip, maximum 16 mm (0.63 in) at the
cable end
HygroVUE™5 Temperature and Relative Humidity Sensor 5

Length: 115 mm (4.52 in), sensor only, without cable
Housing material: White PET-P
Housing classification: IP67 (electronics housing)
Sensor protection: Outer glass-filled polypropylene cap fitted with a stainless steel
mesh dust filter with nominal pore size of <30 µm. The sensor
element is fitted with a PTFE protective film with a filtration
efficiency of >99.99% for particles of 200 nm or larger size.
EMC compliance: Tested and conforms to IEC61326:2013
Calibration: The sensor element is individually calibrated during manufacture.
Compliance documents: View at www.campbellsci.com/hygrovue5
6.1 Temperature measurement
Operating range: –40 to 70 °C
Accuracy*: ±0.4 °C (–40 to 70 °C)
±0.3 °C (20 to 60 °C)
Long term drift: <±0.03 °C/year
Reported resolution: 0.001 °C
Repeatability**: 0.04 °C
Response time: 130 s (63% response time in air moving at 1 m/s)
Units: Degrees Celsius
*The accuracy figures quoted are relative to factory standards.
**Values are 3 standard deviations of 25 measurements at constant temperature.
6.2 Relative humidity measurement
Operating range: 0 to 100% RH
Accuracy (at 25°C)*: ±1.8% (0 to 80% RH)
±3% (80 to 100% RH)
Temperature dependence: < ±1% RH (–40 to 60 °C)
Short term hysteresis: < ±1% RH
Long-term stability: ±0.5% per year (drift in clean air conditions)
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Reported resolution: 0.001% RH
Repeatability**: 0.05% RH
Response time with filter: 8 s (63% response time in air moving at 1 m/s @ 25 °C)
Environmental performance: See Environmental performance (p. 24)
*The accuracy figures quoted are relative to factory standards.
**Values are 3 standard deviations of 25 measurements at constant humidity.
7. Installation
If you are programming your data logger with Short Cut, skip Wiring to data logger (p. 7) and
Data logger programming (p. 8). Short Cut does this work for you. See QuickStart (p. 2) for a
Short Cut tutorial.
7.1 Wiring to data logger
The sensor is fitted with a tough, polyurethane sheathed cable. This has three conductors plus a
shield wire. The wiring of the sensor is shown in Table 7-1 (p. 7).
Table 7-1: Wire color, pin, function, and data logger connection
Pin Wire color Wire function Data logger connection terminal
1 Brown Power 12V
2 White SDI-12 Cterminal or Uterminal
configured for SDI-121
3 Black Power ground G
Clear Shield G
1Uterminals are automatically configured by the measurement instruction.
To use more than one sensor per data logger, either connect the different sensors to different
terminals on the data logger or change the SDI-12 addresses of the sensors and wire them to the
same terminal. Using the SDI-12 address reduces the use of terminals on the data logger and
allows sensors to be connected in a daisy-chain fashion that can minimize cable runs in some
applications. (See Long cables [p. 14] for limits on the total cable length.)
For the CR6 and CR1000X, triggering conflicts may occur when a companion terminal is used for
a triggering instruction such as TimerInput(),PulseCount(), or WaitDigTrig(). For
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