INSTRUCTION MANUAL HMP155A Temperature and Relative Humidity Probe Revision: 10/14 C o p y r i g h t © 1 9 9 0 - 2 0 1 4 C a m p b e l l S c i e n t i f i c , I n c .
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.
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 (435) 227-9000.
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.
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 3.1 Ships With............................................................................................
Table of Contents B.2 B.3 Differential Measurement Example ................................................ B-2 Mean Vapor Pressure Example ....................................................... B-3 C. Interfacing with HMP155A RS-485 Output ............ C-1 C.1 C.2 RS-485 Interface Options ................................................................ C-1 SDM-SIO1 Serial I/O Module Interface Option ............................. C-1 C.2.1 Program Example for SDM-SIO1 Module.............................
HMP155A Temperature and Relative Humidity Probe 1. Introduction The HMP155A probe monitors relative humidity (RH) for the range of 0 to 100% RH and temperature for the range of –80 to 60 °C. It can provide reliable measurements for a wide range of applications, as part of a weather station system or as a single instrument. All Campbell Scientific dataloggers are compatible. NOTE 2. 3. This manual provides information only for CRBasic dataloggers.
HMP155ATemperature and Relative Humidity Probe 3.1 Ships With The HMP155A ships with: (1) Adjustment Screwdriver from manufacturer (1) Calibration Sheet (1) Instruction Manual or ResourceDVD 4. Quickstart Review Section 7, Installation, for siting, wiring, and CRBasic programming information. 4.
HMP155A Temperature and Relative Humidity Probe 2. Squeeze the sides of the white connector cover and insert the cable’s connector through it (see FIGURE 4-2). Cable Connector Connector Cover FIGURE 4-2. Cable routed through the connector cover 3. Attach the cable to the mating connector on the bottom of the HMP155A (see FIGURE 4-3). FIGURE 4-3. Cable connected to the sensor 4. Slide the white connector cover over the connector and gently push it up as far as it will go.
HMP155ATemperature and Relative Humidity Probe 14-Plate Radiation Shield Split Nut U-bolt Connector Cover FIGURE 4-5. HMP155A and 14-plate radiation shield on a tripod mast CM200 Series Crossarm FIGURE 4-6.
HMP155A Temperature and Relative Humidity Probe 4.2 Use SCWin to Program Datalogger and Generate Wiring Diagram Short Cut is an easy way to program your datalogger to measure the HMP155A and assign datalogger wiring terminals. The following procedure shows using Short Cut to program the HMP155A. 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.
HMP155ATemperature 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 | Meteorological | Relative Humidity & Temperature | HMP155 folder. Select HMP155 (constant power) or HMP155 (panel switched power) (shown). Click to move the selection to the Selected device window. The temperature defaults to degrees Celsius.
HMP155A Temperature and Relative Humidity Probe 5. 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, then finish the remaining Short Cut steps to complete the program. The remaining steps are outlined in Short Cut Help, which is accessed by clicking on Help | Contents | Programming Steps. 8.
HMP155ATemperature and Relative Humidity Probe The HMP155A can be powered continuously or the power may be switched to conserve battery life. The HMP155A consumes less than 3 milliamps current at 12 Vdc. Approximately 2 seconds is required for the sensor to warm up after power is switched on. At measurement rates slower than once per 5 seconds, the overall power consumption (datalogger and sensors) may be reduced by switching power to the HMP155A.
HMP155A Temperature and Relative Humidity Probe Electromagnetic compatibility: Complies with EMC standard EN61326-1, Electrical equipment for measurement control and laboratory use - EMC requirements for use in industrial locations Dimensions in mm (inches) 279 [10.98] 266 [10.47] Ø12 [0.47 20 [0.79] 40 [1.57] 86 [3.39] 24 [0.94] FIGURE 6-1. Probe dimensions 8-Pin Connector 0507-044 FIGURE 6-2.
HMP155ATemperature and Relative Humidity Probe *HMP155ACBL1 Cable provided by Campbell Scientific 5=no connection 6=no connection 7=VCC (red) 8=GND (black) - =SHIELD (clear) *Note: HMP155ACBL2 for RS-485 is described in Appendix C. Filter: Sintered PTFE Housing material: PC Housing classification: IP66 Weight: 86 g (3 oz) Inputs and Outputs 6.
HMP155A Temperature and Relative Humidity Probe 6.2 Relative Humidity Sensor Measurement range: Accuracy (including non-linearity, hysteresis and repeatability) at 15 to 25 °C (59 to 77 °F): at –20 to 40 °C (–4 to 104 °F): at –40 to –20 °C (–40 to –4 °F): at 40 to 60 °C (104 to 140 °F): at –60 to –40 °C (–76 to –40 °F): ±1% RH (0 to 90% RH) ±1.7% RH (90 to 100% RH) ± (1.0 + 0.008 × reading) % RH ± (1.2 + 0.012 × reading) % RH ± (1.2 + 0.012 × reading) % RH ± (1.4 + 0.
HMP155ATemperature and Relative Humidity Probe Connections to CRBasic dataloggers are given in TABLE 7-1 and TABLE 7-2. To wire an Edlog datalogger, see an older manual at www.campbellsci.com/old-manuals, or contact a Campbell Scientific application engineer for assistance. CAUTION When measuring the HMP155A with single-ended measurements, the white and black leads must both be .
HMP155A Temperature and Relative Humidity Probe 7.3 Datalogger Programming The temperature and relative humidity signals from the HMP155A can be measured using a single-ended analog measurement or a differential analog measurement. Use a single-ended analog measurement when the HMP155A signal lead length is less than 6.1 m (20 ft) or if the probe will be turned on and off under datalogger control between measurements. For lead lengths greater than 6.
HMP155ATemperature and Relative Humidity Probe The signal reference (white) and the power ground (black) are in common inside the HMP155A. When the HMP155A temperature and relative humidity are measured using a single-ended analog measurement, both the signal reference and the power ground are connected to ground at the datalogger. The signal reference and the power ground both serve as the return path for 12 V. There will be a voltage drop along those leads because the wire itself has resistance.
HMP155A Temperature and Relative Humidity Probe 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 online by the datalogger (see Appendix B.3, Mean Vapor Pressure Examples). 8. Sensor Maintenance The HMP155A probe requires minimal maintenance. Check monthly to make sure the radiation shield is free from debris.
HMP155ATemperature and Relative Humidity Probe When installed in close proximity to the ocean or other bodies of salt water, 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. The filter can be rinsed gently in distilled water.
HMP155A Temperature and Relative Humidity Probe 10. References 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.
HMP155ATemperature and Relative Humidity Probe 18
Appendix A. Importing Short Cut Code 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 A.1 Importing Short Cut Code into a Program Editor Short Cut creates files that can be imported into either CRBasic Editor. These files normally reside in the C:\campbellsci\SCWin folder and have the following extensions: • • • • • • • • .
Appendix A. Importing Short Cut Code After pasting, edit the information such that a ' character (single quotation mark) begins each line. This character instructs the datalogger compiler to ignore the line when compiling the datalogger code.
Appendix B. Example Programs B.1 Single-Ended Voltage Measurement Example Below is an example CR1000 program that uses the single-ended voltage instruction to measure the sensor and uses the datalogger’s SW12V terminal to power the sensor only when it is being measured. TABLE B-1 shows the wiring used for the example. Other CRBasic dataloggers are programmed similarly. TABLE B-1.
Appendix B. Example Programs B.2 Differential Measurement Example Below is an example CR1000 program that uses the differential voltage instruction to measure the sensor and uses the datalogger’s SW12V terminal to power the sensor only when it is being measured. The differential instruction is recommended for long lead lengths. TABLE B-2 shows the wiring used for these examples. Other CRBasic dataloggers are programmed similarly. TABLE B-2.
Appendix B. Example Programs B.3 Mean Vapor Pressure Example Below is an example CR1000 program that computes mean vapor pressure. TABLE B-3 shows the wiring used for these examples. Other CRBasic dataloggers are programmed similarly. TABLE B-3.
Appendix B.
Appendix C. Interfacing with HMP155A RS-485 Output C.1 RS-485 Interface Options The HMP155A outputs a 0 to 1 Vdc signal for temperature and relative humidity that can be measured by all models of Campbell Scientific dataloggers with model HMP155ACBL1 cable. The HMP155A also has RS-485 outputs for temperature and relative humidity that can be interfaced to the CR800, CR1000, and CR3000 dataloggers with model HMP155ACBL2 cable and the SDM-SIO1 Serial I/O Module.
Appendix C.
Appendix C. Interfacing with HMP155A RS-485 Output The public variables for temperature and relative humidity can be viewed in the ‘Numeric Display’ mode as shown below. For troubleshooting purposes, the serial data buffer in the datalogger can be viewed using the ‘W’ terminal command. This is done by connecting to the datalogger from the ‘Connect’ button of LoggerNet or PC400W. From the Connect screen, select Tools|Terminal Emulator.
Appendix C. Interfacing with HMP155A RS-485 Output C.3 MD485 Multidrop Interface Option The MD485 Multidrop Interface can be used to interface the RS-485 outputs of the HMP155A to the datalogger’s CS I/O port. Connect the MD485’s CS I/O port to the datalogger’s CS I/O port with an SC12 cable. Sensor wiring to the MD485 and the datalogger is documented in the example program below. The HMP155A has a default RS-485 baud rate of 4800, which must be changed to 9600 to be compatible with the MD485.
Appendix C. Interfacing with HMP155A RS-485 Output Use the Device Manager in Windows to determine which COM port the USB/RS-485 cable was assigned: Configure Windows HyperTerminal for the appropriate COM port (for example, COM8 in the example above) for the default HMP155A RS-485 settings of 4800 baud, 7, E, 1.
Appendix C. Interfacing with HMP155A RS-485 Output Using HyperTerminal, send the following commands to the HMP155A: VERS[enter] to get a response from the sensor; for example, HMP155A 1.26 SERI[enter] to get the current RS-485 settings; for example, 4800 E 7 1 SERI 9600 N 8 1[enter] to change the RS-485 settings; response should be 9600 N 8 1 R[enter] to put the sensor in the Run mode to output continuous measurements Responses to the commands are shown in the screen capture below.
Appendix C. Interfacing with HMP155A RS-485 Output Connect the MD485’s CS I/O port to the datalogger’s CS I/O port using an SC12 cable. Use the HMP155ACBL2 to connect the HMP155A sensor to the MD485 and the datalogger (CR1000, CR800, or CR3000) as shown in the following table. The table also shows wiring for cables purchased from Vaisala.
Appendix C.
Appendix C. Interfacing with HMP155A RS-485 Output The public variables for temperature and relative humidity can be viewed in the ‘Numeric Display’ mode as shown below. For troubleshooting purposes, the serial data buffer in the datalogger can be viewed using the ‘W’ terminal command. This is done by connecting to the datalogger from the ‘Connect’ button of LoggerNet or PC400W. From the Connect screen, select Tools|Terminal Emulator.
Appendix C.
Campbell Scientific Companies Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah 84321 UNITED STATES www.campbellsci.com • info@campbellsci.com Campbell Scientific Centro Caribe S.A. (CSCC) 300 N Cementerio, Edificio Breller Santo Domingo, Heredia 40305 COSTA RICA www.campbellsci.cc • info@campbellsci.cc Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA www.csafrica.co.za • cleroux@csafrica.co.za Campbell Scientific Ltd.
