Omega Engineering OS533E manual Calculating Temperature

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Appendix: How Infrared Thermometry Works A

Wien’s Displacement Law describes the exact mathematical relationship between the temperature of a blackbody and the wavelength of the maximum intensity radiation.

λm = 2.898

T

where λm = wavelength measured in microns T = temperature in Kelvin

Calculating Temperature

The net thermal power radiated by an object has been shown to depend on its emissivity, its temperature and that of the ambient temperature around the object. A very useful equation known today as the Stefan-Boltzmann Law has been shown both theoretically and empirically to describe the relationship.

I = thermal power in watts/meter2

ε= Emissivity

σ= 5.6703 x 10-8watts/meter2 x K4 (Stefan’s constant) T = temperature of object in Kelvin

Ta = temperature of ambient surroundings in Kelvin

The infrared thermometer uses this equation directly in calculating the temperature of an object. The incident power is measured by the infrared detector. The emissivity of the object is determined by the user. The ambient temperature is measured by a sensor inside the thermometer. With all quantities known, the thermometer uses the Stefan-Bolzmann Law to calculate and output the temperature of the object.

A-3

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Contents User’sGuide Servicing North America Unpacking Instructions Accessories Page Unpacking Instructions Chapter General Description Chapter Maintenance General Description Introduction OS530LE OS530HRE OS530LE-CF OS533E-CF OS534E-CF Features OS523E OS524E Parts of the Thermometer Front of the Thermometer LCDKey General Description General Description Ac Power Operation Installing the BatteriesOperating the Thermometer Field of View PositionsField of View OS534E, OS523E-1 Field of View OS53xE-CF Field of View OS523E-3 Measurement Techniques 11 Recorder Hookup Real Time Mode Active Operation 12. General Operational Block DiagramReal Time Modes 13. Visual Function Flow Chart Using the Lock Function Adjusting EmissivityUsing the Trigger Function Using the Distance Function Must be hard, flat, and reflective to ultrasonic pulseDS = 17. Field of View of Distance Meter HH-DM Calculating Temperature Values Laser Sighting StatusTurning on the Display Backlighting Changing the Temperature from F to C or vice VersaThermocouple Input OS532E, OS533E, OS534E Using the Alarm Functions To set the low alarm value OS533E, OS534E, OS523E, OS524E Use the Ambient Target Temperature Compensation Atcf PC User Application, OS530 Series Operation19. Main Menu Settings Menus 10. Settings Menu21. Typical Temperature Data File PC Interface Commands AsciiString Description Storing Temperature Data on Command OS534E, OS523E, OS524E Logging Temperature Data in Real Time OS523E, OS524E,OS534E Erasing the Temperature Data from Memory Recall Mode Passive Operation ModeRecall Modes Reviewing the Last Parameters Laser Sighting Description Right Side ViewTwo Laser Configurations Operating the Laser SightingLines of Sight of the Laser Sighting and Thermometer Installing and Operating the Sighting Scope Sighting ScopeInstalling the Sighting Scope Safety Warning Maintenance Replacing the BatteriesCalibrating the Thermometer Cleaning the LensServicing the Laser Sighting Troubleshooting Guide Problem SolutionTroubleshooting Guide Problem Troubleshooting Guide Specifications are for all models except where noted SpecificationsGND With Built-in Distance Module Laser Sighting Distance Measuring Built-in-DM Specifications Glossary of Key Strokes Glossary of Key Strokes Thermal Radiation Appendix How Infrared Thermometry Works aBlackbody Calculating Temperature Optics Field of View Metals Appendix Emissivity ValuesNonmetals Appendix Determining an Unknown Emissivity Figure C-1. Determining Emissivity Figure C-2. Determining Emissivity with a Drilled Hole Appendix Determining an Unknown Emissivity Index Field of View Diagrams Recall WARRANTY/DISCLAIMER Temperature PH/CONDUCTIVITY