Campbell HMP50 Instruction Manual
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Campbell HMP50 Instruction Manual

Temperature and relative humidity probe
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HMP50 Temperature and
Relative Humidity Probe
Revision: 10/09
C o p y r i g h t
©
1 9 9 5 - 2 0 0 9
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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Summary of Contents for Campbell HMP50

  • Page 1 HMP50 Temperature and Relative Humidity Probe Revision: 10/09 C o p y r i g h t © 1 9 9 5 - 2 0 0 9 C a m p b e l l S c i e n t i f i c ,...
  • Page 2 Warranty and Assistance The HMP50 TEMPERATURE AND RELATIVE HUMIDITY PROBE is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty.

  • Page 3: Table Of Contents

    9. References ..............13 Figures 1. HMP50 as Shipped ..................4 2. HMP50 and 41303-5A Radiation Shield on a Tripod Mast .......4 3. HMP50 and 41303-5A Radiation Shield on a CM202 Crossarm....5 4. HMP50 and 41303-5A Radiation Shield............5 5. HMP50 Wiring ...................6...
  • Page 4 HMP50 Table of Contents Tables 1. Recommended Lead Lengths..............1 2. Datalogger Connections................6 3. Calibration for Temperature............... 7 4. Calibration for Relative Humidity ............. 7 5. Wiring for CR1000 and CR10X Examples..........7 6. Wiring for Vapor Pressure Examples ............10...

  • Page 5: General

    Resistance Temperature detector (PRT) and a Vaisala INTERCAP® capacitive relative humidity sensor. The -L option on the model HMP50 Temperature and Relative Humidity probe (HMP50-L) indicates that the cable length is user specified. Lead length is specified when the sensor is ordered. Table 1 gives the recommended lead length.

  • Page 6: Temperature Sensor

    HMP50 Temperature and Relative Humidity Probe 2.1 Temperature Sensor Sensor: 1000 Ω PRT, DIN 43760B Temperature Measurement Range: -40°C to +60°C Temperature Output Signal range: 0 to 1.0 VDC Temperature Accuracy: -0.4 -0.8 -1.2 -1.6 Temperature ( 2.2 Relative Humidity Sensor ®...

  • Page 7: Installation

    3.2 Mounting and Assembly Pull off the yellow shipping cap (see Figure 1). The HMP50 must be housed inside a solar radiation shield when used in the field. The 41303-5A 6-Plate Radiation Shield (Figures 2 and 3) mounts to a tripod mast, UT10 tower leg, or CM202, CM204, or CM206 crossarm.

  • Page 8: Hmp50 And 41303-5A Radiation Shield On A Tripod Mast

    HMP50 Temperature and Relative Humidity Probe Yellow Shipping Cap (remove before installation) FIGURE 1. HMP50 as Shipped FIGURE 2. HMP50 and 41303-5A Radiation Shield on a Tripod Mast...

  • Page 9: Hmp50 And 41303-5A Radiation Shield On A Cm202 Crossarm

    HMP50 Temperature and Relative Humidity Probe FIGURE 3. HMP50 and 41303-5A Radiation Shield on a CM202 Crossarm Mounting Clamp FIGURE 4. HMP50 and 41303-5A Radiation Shield...

  • Page 10: Example Programs

    Shield Clear 4. Wiring Connections to Campbell Scientific dataloggers are given in Table 2. The probe is measured by two single-ended analog input channels, one for temperature and one for relative humidity. Always connect the Blue lead to the datalogger first, CAUTION followed by the Black, White, and Clear leads.

  • Page 11: Wiring

    HMP50 Temperature and Relative Humidity Probe The temperature and relative humidity signals from the HMP50 are measured using two single-ended analog measurements (Instruction 1). The probe output scale is 0 to 1000 millivolts for the temperature range of -40°C to +60°C and for the relative humidity range of 0 to 100%. Tables 3 and 4 provide calibration information for temperature and relative humidity.

  • Page 12: Example For Cr10X

    HMP50 Temperature and Relative Humidity Probe BeginProg Scan(5,Sec,1,0) 'HMP50 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 CallTable(Table1) NextScan EndProg 5.2 Example for CR10X ;Measure the HMP50 temperature. 01: Volt (SE) (P1)

  • Page 13: Long Lead Lengths

    Understanding the following details are not required for the general operation of the HMP50 with Campbell Scientific’s dataloggers. The signal reference and the power ground (black) are the same lead in the HMP50. When the HMP50 temperature and relative humidity are measured, both the signal reference and power ground are connected to ground at the datalogger.

  • Page 14: Cr1000 Vapor Pressure Example

    HMP50 Temperature and Relative Humidity Probe 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. (2) that a change in air temperature will change the relative humidity, without causing a change in absolute humidity.

  • Page 15: Sample Cr10(X) Program That Computes Vapor Pressure And Saturation Vapor Pressure

    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) 'HMP50 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 7.2 Sample CR10(X) Program that Computes Vapor Pressure and Saturation Vapor Pressure ;Measure the HMP50 temperature.

  • Page 16: Maintenance

    3: 4 Z Loc [ e 8. Maintenance The HMP50 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.

  • Page 17: Procedure For Removing Rh Chip

    9598 RH Chip FIGURE 6. Exploded View of HMP50 (as shipped) The offset and gain on the HMP50 electronics can not be adjusted as part of a recalibration. Replace the RH chip as needed. 8.1 Procedure for Removing RH Chip 1.
  • Page 18 HMP50 Temperature and Relative Humidity Probe...
  • Page 20 Campbell Scientific Companies Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah 84321 UNITED STATES www.campbellsci.com • info@campbellsci.com Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA www.csafrica.co.za • cleroux@csafrica.co.za Campbell Scientific Australia Pty. Ltd. (CSA)

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