Omega Engineering OS523, OS530HR, OS531, OS53X-CF, OS524 Appendix Determining an Unknown Emissivity

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Appendix: Determining an Unknown Emissivity

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In Appendix A, we showed how emissivity is an important parameter in calculating the temperature of an object via infrared means. In this section we discuss how to determine a specific emissivity value. If you know the material of the object, use Table B- 1 in Appendix B to look up its approximate emissivity. Most organic materials such as plastics, cloth, or wood have an emissivity of about 0.95. For this reason, we use 0.95 as the default emissivity setting in the OS530 Series Thermometer.

For objects of unknown material or for very precise measurements, use one of the following methods to determine a specific emissivity value.

Method 1

1.Measure and record the temperature of the object using a contact temperature probe such as a thermocouple or RTD.

2.Aim the thermometer at the object.

3.Adjust the emissivity until the temperature reading of the thermometer equals the temperature measured in Step 1.

Method 2

1.Heat the object (or at least a sample of the object material) on top of a heating plate to a known temperature. Make sure the thermometer and the air surrounding the heating plate are at the same temperature.

2.Measure the temperature of the object material with the thermometer. Make sure that the object fills the FOV of the thermometer.

3.Adjust the emissivity until the temperature reading of the thermometer equals the known temperature of Step 1.

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Contents User’s Guide For immediate technical or application assistance Servicing North AmericaServicing Europe Unpacking Instructions Model No Description Page Unpacking Instructions Chapter General Description Contents General Description Introduction Features OS531 OS532 OS533 OS534 OS530HR OS530L-CF Features OS523 OS524 Parts of the Thermometer Front of the ThermometerDisplay Details Key Rear of the Thermometer OS530 Series Handheld Infrared Thermometer Rear ViewGeneral Description Battery Operation Ac Power OperationOperating the Thermometer OS530/OS520 Series with Built-in Laser SightingField of View OS531, OS532, OS530L Field of View OS534, OS523-1 Field of View OS523-2 10 Field of View OS524 Measurement Techniques Trigger11 Recorder Hookup Real Time Mode Active Operation If the trigger is pulled two times in rapid sequenceRecall Mode 13. Visual Function Flow Chart Adjusting Emissivity Using the Lock FunctionChanging the Temperature from F to C or vice versa Calculating Temperature ValuesTurning on the Display Backlighting Thermocouple Input OS532, OS533, OS534 Using the Alarm Functions If you are not in High Alarm Display Mode HAL whenTo set the low alarm value OS533, OS534, OS523, OS524 To disable this mode, press the key again Icon disappears One Stop Bit Key to decrement the printing interval. System Requirements Irtempsoft Connecting the IR-System to the PC Using the Handheld Infrared Thermometer Storing the Temperature Data on Command OS534, OS523, OS524 Erasing the Temperature Data from Memory Recall Mode Passive Operation ModeFunctional Flow Chart Recall Mode AMB temperature MEM location Reviewing the Last ParametersPRN F Using the Handheld Infrared Thermometer Laser Sighting Description Rear ViewOperating the Laser Sighting Laser DotLines 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 SolutionProblem If you see an error code, either Target are offset by design Specifications are for all models except where noted SpecificationsOS533, OS534, OS523, OS524 No Laser Sighting 17 hours continuous Laser Sighting 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 Material Emissivity εAppendix 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 Shop online at omega.com PH/CONDUCTIVITY