HMP60 Temperature and Relative Humidity Probe Revision: 7/12 C o p y r i g h t © 1 9 9 5 - 2 0 1 2 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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HMP60 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 4.
HMP60 Table of Contents Figures 4-1. 4-2. 4-3. 4-4. 7-1. 8-1. HMP60 as shipped.................................................................................. 3 HMP60 and 41303-5A Radiation Shield on a tripod mast ..................... 3 HMP60 and 41303-5A Radiation Shield on a CM202 Crossarm........... 4 HMP60 and 41303-5A Radiation Shield................................................ 4 HMP60 wiring ......................................................................................
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. Before using the HMP60, please study • • • Section 2, Cautionary Statements Section 3, Initial Inspection Section 4, Quickstart More details are available in the remaining sections. 2.
HMP60 Temperature and Relative Humidity Probe 4. Quickstart 4.1 Step 1 — Mount the Probe Review Section 7, Installation for complete instructions. To install the HMP60, you will need: • • • • • • CAUTION 2 41305-5A 6-plate Radiation Shield 1/2" open end wrench small screw driver provided with datalogger small Phillips screwdriver UV resistant cable ties small pair of diagonal-cutting pliers 1. Pull off the yellow shipping cap (see Figure 4-1). 2.
HMP60 Temperature and Relative Humidity Probe Yellow Shipping Cap (remove before installation) FIGURE 4-1. HMP60 as shipped FIGURE 4-2.
HMP60 Temperature and Relative Humidity Probe FIGURE 4-3. HMP60 and 41303-5A Radiation Shield on a CM202 Crossarm Mounting Clamp FIGURE 4-4.
HMP60 Temperature and Relative Humidity Probe 4.2 Step 2 — Use SCWin Short Cut to Program Datalogger and Generate Wiring Diagram The simplest method for programming the datalogger to measure the HMP60 is to use Campbell Scientific's SCWin Short Cut Program Generator. 1. Open Short Cut and click on New Program. 2. Select a datalogger and scan interval.
HMP60 Temperature and Relative Humidity Probe 6 3. Select HMP50/HMP60 Temperature and Relative Humidity Sensor then click the right arrow to add it to the list of sensors to be measured. 4. Define the name of the public variables. Variables default to AirTC and RH that hold the air temperature and relative humidity measurements. Select the desired units of measure. Units default to Deg C.
HMP60 Temperature and Relative Humidity Probe 5. Choose the outputs for the AirTC and RH and then select finish. 6. Wire according to the wiring diagram generated by SCWin Short Cut. 5. Overview The HMP60 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 HMP60 Temperature and Relative Humidity probe (HMP60-L) indicates that the cable length is user specified.
HMP60 Temperature and Relative Humidity Probe TABLE 5-1. 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.
HMP60 Temperature and Relative Humidity Probe 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: Filter Cap Material: Classification: AISI 316 stainless steel Chrome-coated ABS plastic IP65 Power Consumption: 1 mA typical; 5 mA maximum Supply Voltage: 5 to 28 Vdc Settling Time after power is switched on: 1 second Output Signal Range: 0 to 1 Vdc 6.
HMP60 Temperature and Relative Humidity Probe 7. Installation 7.1 Siting Sensors should be located over an open level area at least 9 m (EPA) in diameter. The surface should be covered by short grass, or where grass does not grow, the natural earth surface. 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 Black Temperature Signal White Relative Humidity Signal Blue Signal & Power Reference Brown Power Clear Shield FIGURE 7-1. HMP60 wiring TABLE 7-1.
HMP60 Temperature and Relative Humidity Probe The temperature and relative humidity signals from the HMP60 are measured using two single-ended analog measurements (VoltSE() in CRBasic or Instruction 1 in Edlog). 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%. Tables 7-2 and 7-3 provide calibration information for temperature and relative humidity. TABLE 7-2.
HMP60 Temperature and Relative Humidity Probe 7.4.2 Example for CR10X ;Measure the HMP60 temperature. ; 01: Volt (SE) (P1) 1: 1 Reps 2: 5 2500 mV Slow Range 3: 4: 5: 6: 3 1 .1 -40 SE Channel Loc [ T_C Mult Offset ] ;See Table 7-2 for alternate multipliers ;See Table 7-2 for alternate offsets ;Measure the HMP60 relative humidity. ; 02: Volt (SE) (P1) 1: 1 Reps 2: 5 2500 mV Slow Range 3: 4: 5: 6: 4 3 .
HMP60 Temperature and Relative Humidity Probe 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 (P/N 18159) has resistance of 26.2 Ω/1000 feet. Using Ohm’s law, the voltage drop (Vd), along the signal reference/power ground lead, is given by Eq.
HMP60 Temperature and Relative Humidity Probe VaporPressure() instruction to calculate vapor pressure from temperature and relative humidity measurements (see Section 7.6.1). Edlog dataloggers must first calculate the saturation vapor pressure and then calculate vapor pressure (see Section 7.6.2). TABLE 7-5.
HMP60 Temperature and Relative Humidity Probe 7.6.2 Sample CR10(X) Program that Computes Vapor Pressure and Saturation Vapor Pressure ;Measure the HMP60 temperature. ; 01: Volt (SE) (P1) 1: 1 Reps 2: 5 2500 mV Slow Range 3: 4: 5: 6: 3 1 .1 -40 SE Channel Loc [ T_C Mult Offset ] ;Measure the HMP60 relative humidity. ; 02: Volt (SE) (P1) 1: 1 Reps 2: 5 2500 mV Slow Range 3: 4: 5: 6: 4 2 .
HMP60 Temperature and Relative Humidity Probe 8. Maintenance The HMP60 Probe requires minimal maintenance. Check monthly to make sure the radiation shield is free from debris. The white screen at the tip of the probe 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.
HMP60 Temperature and Relative Humidity Probe 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. 9. Troubleshooting Symptom: NAN, -9999, or 0 % relative humidity 1. Check that the sensor is wired to the correct analog input channels as specified by the measurement instructions. 2. Verify the voltage range code for the single-ended measurement instruction is correct for the datalogger type.
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