Fluke Ti20 user manual Adjusting the Span, Manually Activating the Calibration Flag

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Basic Operation 2

Adjusting the Span

Adjusting the Span

The full temperature span of the Imager is -10 °C to 350 °C (14 °F to 662 °F). The LCD display shows about 256 shades of color for whatever pallet you select. Adjusting the temperature span allows you to see more subtle temperature gradients in a captured image.

For example, if you are viewing an image with a temperature span from 10 °C to 30 °C and are using the Imager at full temperature span, the image will be concentrated into only about 15 of the 256 shades that could be shown. Reducing the temperature span to 10 °C to 30 °C allows you to view the display with the full range of about 256 shades.

1.Press G(HOME) one time from the Home display to access the set Mode menu.

2.Press F(MANUAL) to manually set Level and Scan mode or H(AUTO) to have the Imager automatically set Level and Scan.

3.Press H(SPAN) to access the set Span function.

4.Press F(5 4) to close the range window or H(4 5) to open the range window. The minimum temperature span setting is 5 °C.

Manually Activating the Calibration Flag

When the Imager is first turned on, the image freezes briefly from time to time and an hourglass icon appears briefly on the display. This is a normal process that happens when the unit momentarily shuts down the optical channel to eliminate offset errors. This is a recalibration sequence that begins immediately after the unit is turned on.

Recalibration intervals occurs at 15, 30, 45, and 60 seconds and continues every

60 seconds unless a change in ambient temperature occurs. A change in the internal temperature of 0.2 °C (0.4 °F) forces the Imager to recalibrate before the 60 seconds are up and the new calibration cycle starts at that time.

To manually activate the calibration flag, press H(FLAG) from the Main or Home menu to start the recalibration sequence.

Using Distance to Spot Size Ratio (D:S)

The Ti20 imager views a portion of the scene that is 15 º high by 20 º wide (the Field-Of- View (FOV), of the Imager) as shown in Figure 2-3. This scene is displayed on the LCD on the back of the Imager. The single temperature displayed numerically at the lower edge of the display, however, corresponds to a measurement of a much smaller part of the scene. In particular, it corresponds to the average temperatures of the area seen through the “hole” in the center of the reticle on the LCD display (see Figure 2-3).

The actual diameter of the measurement spot at the object is calculated by dividing the distance to the object by 75 (the D:S for the Imager). If the Imager is properly focused on a target 100 inches away, the diameter of the measurement spot on the object will be (100 inches) ÷ 75 = 1.33 inches. If the Imager is focused on a target 24 inches away, the diameter of the measurement spot on the object will be (24 inches) ÷ 75 = 0.32 inches.

To achieve the smallest measurement spot (D:S = 75:1), the imager must be properly focused on the object being measured.

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Contents Ti20 Limited Warranty and Limitation of Liability Table of Contents Ti20 List of Tables Ti20 List of Figures Ti20 Getting Started IntroductionContacting Fluke Symbols Safety InformationLaser Warning Labels Ti20Unpacking the Imager Standard AccessoriesUnpacking the Imager Ti20 Features and ControlsOperating the Controls Focusing the ImagerUnderstanding the Trigger Ti20Using the AC Power Adapter Using the AC Power AdapterCharging and Replacing the Batteries Using the Battery ChargerReplacing the Battery Pack Installing or Replacing the BatteriesAttaching the Wrist Strap Attaching the Wrist StrapInputs and Connections Connecting the USB CableCleaning Cleaning the CaseMounting the Imager on a Tripod Cleaning the Lens Ti20 Turning the Imager On and Off Basic OperationImager Home Display Zones Understanding the Home DisplayContents of the Home display is described in Table Aiming and Activating the Laser Comparing Frozen Images to Stored Images Capturing ImagesAdjusting the Backlight Setting the Level Setting the Temperature ScalePress Flevel to access the set Level function Adjusting the Span Using Distance to Spot Size Ratio DSManually Activating the Calibration Flag FOV Environmental Conditions Ambient Temperature Derating and Thermal ShockEmissivity Tape methodContact thermometer method Reflected Temperature Compensation Reflected Temperature CompensationTi20 Advanced Imager Operation Data Management and StorageViewing Stored Images Deleting Images Selecting a Palette Adjusting Emissivity Press FNto access the Adjust Emissivity display Adjusting Reflected Temperature Compensation Values Setting Alarm Limits Dag124f.bmp Adjusting Sleep Mode Ti20 Appendices Page Glossary Blackbody Display ResolutionCalibration Calibration SourceFocus Point or Distance Field of View FOVFull Scale Full Scale AccuracyLevel Optical ResolutionMicron or µm Minimum spot sizeResolution Reflected Temperature CompensationRelative Humidity RepeatabilityTemperature Storage Temperature RangeTemperature Coefficient or Ambient Derating Temperature ResolutionWhy use non-contact infrared thermometers? Basics of Infrared MeasurementHow does IR work? What is emissivity? How to assure accurate temperature measurement?What is the distance to spot ratio? How to take temperature measurement?What are some uses for non-contact thermometers? Ti20 Typical Emissivity Values Table C-1. Emissivity Values for Metals Material To 14 µm Table C-1. Emissivity Values for Metals Material To14 µm Tin Unoxidized 0.3 Titanium Polished Typical Emissivity Values Ti20 Thermal SpecificationsOther
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