INSTRUCTION MANUAL HMP155A Temperature and Relative Humidity Probe Revision: 5/14 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 .
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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. Example Programs.................................................. B-1 B.1 Single-Ended Voltage Measurement Examples .............................. B-1 B.1.1 CRBasic Single-Ended Measurement Program ........................ B-1 B.1.2. Edlog Single-Ended Measurement Program ............................ B-2 B.2 Differential Measurement Examples ............................................... B-3 B.2.1 CRBasic Differential Measurement Program ........................... B-3 B.2.
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.
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 and Edlog 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 procedures 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 current at 12 volts. 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. Most current Campbell Scientific dataloggers have a built-in switched 12 volts that can be used to control power.
HMP155A Temperature and Relative Humidity Probe 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 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): 0 to 100% RH ±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 CAUTION When measuring the HMP155A with single-ended measurements, the white and black leads must both be connected to AG on the CR10(X) and CR500/CR510 or to on the CR1000, CR5000, and CR23X. Doing otherwise will connect the datalogger’s analog and power ground planes to each other, which in some cases can cause offsets on low-level analog measurements. To avoid 3 mA flowing into analog ground, switch the sensor on/off for its own measurement. TABLE 7-1.
HMP155A Temperature and Relative Humidity Probe TABLE 7-2.
HMP155ATemperature and Relative Humidity Probe datalogger control between measurements. For lead lengths greater than 6.1 m (20 ft.) or when the probe will be continuously powered, use a differential analog measurement. For a discussion on errors caused by long lead lengths see Section 7.4. NOTE HMP155A sensors purchased directly from Vaisala with serial numbers < E4430001 require approximately 5 seconds warm up time.
HMP155A Temperature and Relative Humidity Probe Ω/1000 feet, or 13.9 Ω/1000 feet. Using Ohm’s law, the voltage drop (Vd), along the signal reference/power ground, is given by Eq. (1). Vd = I ∗R = 4 mA ∗ 13.9 Ω 1000 ft = 55.6 mV 1000 ft (1) This voltage drop will raise the apparent temperature and relative humidity because the difference between the signal and the signal reference lead, at the datalogger, has increased by Vd. The approximate error in temperature and relative humidity is 0.56°C and 0.
HMP155ATemperature and Relative Humidity Probe 8. Sensor Maintenance The HMP155A Probe requires minimal maintenance. Check monthly to make sure the radiation shield is free from debris. The filter at the end of the sensor should also be checked for contaminates. 8.1 Periodic Maintenance 8.1.1 Cleaning Clean the probe with a soft, lint-free cloth moistened with mild detergent. 8.1.2 Changing the Probe Filter 1. Remove the filter from the probe. 2.
HMP155A Temperature and Relative Humidity Probe 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. If necessary, the chip can be removed and rinsed as well. Do not scratch the chip while cleaning. Long term exposure of the HUMICAP relative humidity sensor to certain chemicals and gases may affect the characteristics of the sensor and shorten its life.
HMP155ATemperature 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.
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 or Edlog program editor. These files normally reside in the C:\campbellsci\SCWin folder and have the following extensions: • • • • • • • • .
Appendix A. Importing Short Cut Code 5. The program can now be edited, saved, and sent to the datalogger. 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 mark) begins each line.
Appendix B. Example Programs B.1 Single-Ended Voltage Measurement Examples These examples use the single-ended voltage instruction to measure the sensor and use the datalogger’s SW12V terminal to power the sensor only when it is being measured. TABLE B-1 shows the wiring used for these examples. TABLE B-1.
Appendix B. Example Programs B.1.2. Edlog Single-Ended Measurement Program Below is an example CR10X program. Information about using it with other Edlog dataloggers are provided in the program’s comments. ;Turn the HMP155A on. ; 01: Do (P86) 1: 41 Set Port 1 High ;Jumper wire from SW12V control to C1 ;Green wire (C1) if using SW12V Power Switch ;For CR23X or CR5000 use 49 for SW12V internal ;control port ;Pause 2 seconds before making measurements so the ;probe can stabilize on true readings.
Appendix B. Example Programs B.2 Differential Measurement Examples These examples use the differential voltage instruction to measure the sensor and use 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. TABLE B-2.
Appendix B. Example Programs B.2.2 Edlog Differential Measurement Program Below is an example CR10X program. Information about using it with other Edlog dataloggers are provided in the program’s comments. ;Turn the HMP155A on. ; 01: Do (P86) 1: 41 Set Port 1 High ;Jumper wire from SW12V control to C1 ;Green wire (C1) if using SW12V device ;For CR23X or CR5000 use 49 for SW12V internal ;control port ;Pause 2 seconds before making measurements so the ;probe can stabilize on true readings.
Appendix B. Example Programs B.3 Mean Vapor Pressure Examples These examples compute mean vapor pressure. TABLE B-3 shows the wiring used for these examples. TABLE B-3. Wiring for Vapor Pressure Examples Color Description CR1000 CR10(X) Yellow Temperature SE 2 (1L) SE 3 (2H) Blue Relative Humidity SE 1 (1H) SE 4 (2L) White Signal Reference AG Jumper from SW12V Control C1 Red Power SW12V SW12 V Black Power Ground AG Clear Shield G B.3.
Appendix B. Example Programs B.3.2 Edlog Vapor Pressure and Saturation Vapor Pressure Program Below is an example CR10X program. Information about using it with other Edlog dataloggers are provided in the program’s comments. ;Turn the HMP155A on.
Appendix B. Example Programs ;Compute the vapor ;Relative humidity ; 07: Z=X*Y (P36) 1: 3 X 2: 2 Y 3: 4 Z pressure. must be a fraction.
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 RS485 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.
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