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Model HFP01 Soil Heat Flux Plate 

1.  Introduction 

The HFP01 outputs a voltage signal that is proportional to the heat flux of the 
surrounding medium (usually soil).  It is typically used for energy-balance or 
Bowen-ratio flux systems.  At least two sensors are required for each site to 
provide spatial averaging.  Sites with heterogeneous media may require 
additional sensors.  

Before installing the HFP01, please study 

 

Section 2, 

Cautionary Statements 

 

Section 3, 

Initial Inspection 

The installation procedure is provided in Section 6. 

2.  Cautionary Statements 

 

Care should be taken when opening the shipping package to not damage 
or cut the cable jacket.  If damage to the cable is suspected, consult with a 
Campbell Scientific applications engineer. 

 

Although the HFP01 is rugged, it should be handled as a precision 
scientific instrument. 

3.  Initial Inspection 

 

Upon receipt of the HFP01, inspect the packaging and contents for 
damage.  File damage claims with the shipping company. 

 

The model number and cable length are printed on a label at the 
connection end of the cable.  Check this information against the shipping 
documents to ensure the correct product and cable length are received. 

 

The HFP01 is shipped with a calibration sheet and an instruction manual 
or a ResourceDVD.  

4.  Overview 

The HFP01 Soil Heat Flux Plate uses a thermopile to measure temperature 
gradients across its plate.  Operating in a completely passive way, it generates 
a small output voltage that is proportional to this differential temperature.  
Assuming that the heat flux is steady, that the thermal conductivity of the body 
is constant, and that the sensor has negligible influence on the thermal flow 
pattern, the signal of the HFP01 is directly proportional to the local heat flux. 

Summary of Contents for HFP01

Page 1: ...Model HFP01 Soil Heat Flux Plate Revision 7 12 C o p y r i g h t 2 0 0 2 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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Page 3: ...emoving reinstalling and shipping defective products to Campbell Campbell will return such products by surface carrier prepaid within the continental United States of America To all other locations Ca...

Page 4: ...g container Campbell Scientific s shipping address is CAMPBELL SCIENTIFIC INC RMA _____ 815 West 1800 North Logan Utah 84321 1784 For all returns the customer must fill out a Statement of Product Clea...

Page 5: ...Wiring 5 6 3 Programming 5 6 4 Soil Heat Flux and Storage 7 7 Maintenance 8 8 References 8 Appendix A General Theory of Heat Flux Sensors A 1 A 1 General Theory A 1 A 2 Extended Theory A 2 Figures 6...

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Page 7: ...hould be handled as a precision scientific instrument 3 Initial Inspection Upon receipt of the HFP01 inspect the packaging and contents for damage File damage claims with the shipping company The mode...

Page 8: ...he sensor as the HFP01 The sensor s cable can terminate in Pigtails that connect directly to a Campbell Scientific datalogger option PT Connector that attaches to a prewired enclosure option PW Refer...

Page 9: ...must be completely inserted into the soil face before the hole is backfilled FIGURE 6 1 Placement of heat flux plates 6 Installation 6 1 Placement in Soil The standard set of sensors for measuring soi...

Page 10: ...t the side with the red label is facing the sky and the side with a blue label facing the soil NOTE In order for the HFP01 to make quality soil heat flux measurements the plate must be in full contact...

Page 11: ...Shield Clear G 6 3 Programming To calculate the calibration multiplier divide 1000 by the nominal calibration sensitivity i e 1000 sensitivity The nominal calibration sensitivity is unique for each HF...

Page 12: ...P01 1 1000 sensitivity 1000 67 1 Const HFP01_CAL_2 14 92 Unique multiplier for HFP01 2 1000 sensitivity 1000 67 0 Variables Energy balance sensors Public shf 2 Dim shf_cal 2 Soil heat flux plate calib...

Page 13: ...n of CR23X Program using the Differential Measurement Instruction The instruction below does not store data in final storage P92 P77 and an output processing instruction are required to store the data...

Page 14: ...lk density and mass basis soil water content can be found by sampling Klute 1986 The volumetric soil water content is measured by the CS616 water content reflectometer A value of 840 J kg 1 K 1 for th...

Page 15: ...and the thermal conductivity of the sensor Using more thermocouples in series will enhance the output signal In Figure A 1 the joints of a copper constantan thermopile are alternatively placed on the...

Page 16: ...r of magnitude of this error for strongly different thermal conductivity values between the sensor and its environment for example 0 6 for a typical sensor and 0 03 for an insulating wall is about 40...

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Page 18: ...ntific Canada Corp CSC 11564 149th Street NW Edmonton Alberta T5M 1W7 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300 N Cementerio Edificio Breller...

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