PO Box 1 Ilkley West Yorkshire Phone: 01943 602001 LS29 8EU Fax: 01943 816796 instrumentation n Website: www.issltd.co.uk Email: sales@issltd.co.uk Systems & Services Ltd ThermoView Ti30 User’s Manual July 1, 2003 Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
CONTENTS Introduction..................................................................................................................... 7 Quick Specifications Table ............................................................................................. 8 Chapter 1 Unpacking Your New Imager ................................................... 9 First, the Batteries .........................................................................................................
Looking at Your Downloaded Images.......................................................................... 38 Chapter 4 Obtaining the Best Image ........................................................ 41 The Importance of Focusing ......................................................................................... 41 Selecting the Color Palette............................................................................................ 42 Selecting the Measurement Mode................................
Appendix B – Infrared Theory Q&A........................................................ 71 Glossary ....................................................................................................... 75 July 1, 2003 -4- Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
© 2003 Raytek Corporation. The information contained in this document is subject to change without notice. Raytek and the Raytek logo are registered trademarks and ThermoView and InsideIR are trademarks of Raytek Corporation. Windows is a registered trademark of Microsoft Corporation in the United States and/or other countries. Pentium is a registered trademark of Intel Corporation or its subsidiaries in the United States and other countries.
Customer Service Contact Information Instrumentation Systems & Services Ltd P.O. Box 1 ILKLEY West Yorks LS29 9QE UK July 1, 2003 -6- Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Introduction The Raytek ThermoView Ti30 imager is a state-of-the-art, lightweight, gun-grip style thermal imaging unit that lets you obtain instant and accurate thermal images and radiometric readings at a remote distance from your target. Ergonomically designed for either left or right-handed use, the ThermoView imager captures thermal images and data with a simple click of the trigger.
Power Battery Life Data Transfer Storage Device 6 AA batteries(not included) or rechargeable battery pack (included) Min. 5 hours continuous use USB interface, total transfer time up to 30s for 100 pictures Flash Memory Tripod Mount (6.
Chapter 1 Unpacking Your New Imager Begin by opening the shipping box. Be sure to save the box and shipping materials in the event you need to ship the imager.
First, the Batteries The battery compartment is located in the handle of the unit. The unit is shipped with an empty battery pack for non-rechargeable batteries installed in the battery compartment. Battery Lock Tab Remove the empty battery pack from the battery compartment. The battery pack can be removed by sliding the lock tab towards the trigger. Move the lock tab in this direction Once the lock is released, the battery pack will slide down. Tilt the top of the unit up to slide the battery pack out.
At this point, you have two options: insert six new AA batteries into the empty nonrechargeable batteries pack or replace it with the supplied rechargeable battery pack. You will notice the difference between the two battery packs as shown in Figure 2 below: Rechargeable battery pack Non-rechargeable battery pack (batteries not included) Figure 2. Battery Packs To replace the battery pack just slide it back in, making sure the plastic tab lock is in the unlocked position (to the right of the pack).
Charging the Rechargeable Battery Pack Docking Station Connect the docking station to a power outlet using the supplied universal power adapter. Be sure to use the plug adapter that fits your local electrical standards. Connect the power jack of the power adaptor to the DC power inlet located on the docking station. DC Power inlet USB cable Normal Charge Cycle x With the ThermoView unit powered off, place it on the docking station. x Do not connect the USB cable to the computer at this point.
A charge cycle takes a rechargeable battery pack from whatever level of charge it presently has and brings it to a fully charged condition. The charger will not over-charge a battery pack no matter how many times the button is pushed. RED light Restart / Sync button GREEN light Figure 4. Docking Station LED Indicators Note: You may download stored images from the ThermoView imager to a personal computer if the docking station’s USB cable is connected to a computer running the InsideIR software.
Chapter 2 Getting Started Your ThermoView imager has settings and capabilities that let you customize its operation for the task at hand. The following section describes each setting on the imager. Attaching the Wrist Strap Your ThermoView imager comes with a wrist strap, which can be attached by clipping the metal part of the strap to the small metal bar at the base of the imager (see Figure 5 below). Attach wrist strap Figure 5. Attaching the Wrist Strap July 1, 2003 - 14 - Version 1.
Turning the Unit On Power is switched on or off by opening or closing the lens door. Sliding down the lens door turns the imager on (see Figure 6 below). Slide the door up to turn off the imager. Closed (Unit Off) Open (Unit On) Figure 6. Powering the ThermoView Imager On and Off Note: The unit is self-protected against excessive levels of infrared radiation and it will cause the unit to automatically shut down. If that happens, slide the lens door closed, wait a minute and slide it open again.
x Unit Serial Number x Date and Time (configured by the user through the software) x Tag name is the name of the user-defined folder from which data was uploaded through the software. Useful tag names are department names or area associated with the unit. This space is blank until configured by the user. x Station is the name of the networked computer associated with a specific unit. This is blank until configured by the user.
Target Temperature Temperature scale Emissivity value Location name LCD backlight icon Palette icon Mode icon Figure 8. Normal Mode Take time to experiment with the imager and become familiar with how the thermal image is updated on the display as you aim the imager at different targets with different thermal patterns. Notice how images display in varying colors, which are related to the different target temperatures.
Settings and Controls Keypad Three buttons located below the LCD screen allow you to select operation modes and change parameter values. These buttons are the MODE button, the Up button, and the Down button. The Up and Down buttons are used mostly to increment and decrement parameter values. They activate some special functions as well. The MODE button is used mostly to cycle between the different operations. Details about the function of each button are discussed later.
Push buttons (toggle) Pull door up to show control switches 3-position Switches Thumbwheels Figure 10. ThermoView Imager Settings Switches (icons not shown) The illustration below shows the top view of the switch bay without the door. There is an icon printed near each switch and near each switch position indicating the function of each switch and switch position. These functions are explained in the next paragraphs. July 1, 2003 - 19 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Laser ON/OFF Centigrade / Fahrenheit selection LCD backlight selection Palette selection Measurement mode selection Level adjustment Gain adjustment Figure 11. ThermoView Imager Settings Switches Laser On/Off Toggle Button The Laser On/Off toggle button switches the laser on and off. By default, the guiding laser beam is off. Depending on the situation you may or may not need the laser guidance beam. July 1, 2003 - 20 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Laser Aperture Optical Channel Figure 12. Laser Aperture and Optical Channel Note: The laser is only a sighting aid. It is not required to take measurements. The laser is not coaxial with the infrared channel, thus the laser dot is offset from the center of the thermal image. The laser dot is not visible in the thermal image. Important: Avoid directing the laser to people’s eyes. See important safety information on the warning laser label located on the side of the unit.
Centigrade/Fahrenheit Toggle Button Centigrade/Fahrenheit button toggles the displayed temperature data in either Centigrade or Fahrenheit temperature scales. The factory default is Centigrade. LCD Backlight Illumination Switch LCD Backlight Illumination switch provides three backlight illumination levels as shown below. Off Medium Full Full brightness is recommended for indoor use; use Medium brightness to save battery life, and set backlight Off for outdoor applications.
There are three measurement mode positions associated with this switch: Automatic Semi Automatic Manual In Automatic mode the ThermoView imager automatically adjusts the image to show the lowest temperature value present in the thermal scene (MIN) and the highest temperature value in the scene (MAX). Semi-Automatic mode the ThermoView imager keeps calculating the MIN limit In (lowest temperature value on the thermal scene) automatically. In Manual mode the user can adjust Gain and Level manually.
Focus Wheel Figure 14. Location of the Focus Wheel See The Importance of Focusing on page 41 for more details. Trigger Actuating the trigger freezes an image prior to storage. While in a regular measurement mode, pull the trigger momentarily, release it, and the thermal image on the display will be frozen so you can evaluate it for storage. If you don’t want to store it, simply pull the trigger again and the unit will go back to measurement mode. Trigger Figure 15.
Man Machine Interface Flow Charts Main Loop July 1, 2003 - 25 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Image Recording Procedure Emissivity Adjustment Procedure July 1, 2003 - 26 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Reflected Temperature Compensation Adjustment Procedure Recall Images Procedure July 1, 2003 - 27 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Quick Image Fix Procedure Array Recalibration Procedure Recording an Image Recording images with the ThermoView imager is simple. Repeat the steps below and record as many images you want until you get familiar with the process. x First, note the number of the current image location. At this point, if you have not stored any images, the location number should be set at 1 (default) and the location descriptor will be blank.
Note: To erase an image, just store a new image over the one you wish to delete. To do this, go to Recall Images Procedure, press Down button once to decrement the location, press Mode button or trigger to get back to measurement mode, and pull trigger again to save a new image. Retrieving an Image On Measurement mode, press the MODE button 3 times, browsing through Emissivity Adjustment and Reflected Temperature Adjustment modes (these adjustments are explained in Chapter 3 ).
Chapter 3 Downloading and Looking at Images This chapter begins with the InsideIR software installation.
Connecting the Docking Station to Your Computer The docking station provides a solid and convenient base for the ThermoView imager. The docking station keeps the ThermoView imager available and connected to the computer or workstation. In addition, it keeps the batteries charged and ready to go. The docking station connects to your computer through its USB port. The USB cord should remain connected to the computer at all times.
Figure 18. Connecting the USB Connector to the USB Port x Dock the imager in the docking station. x The first time you place the imager in its docking station and press the SYNC button with the docking station connected, your computer's operating system will detect new hardware and locate the correct communication driver. Your computer will automatically launch its own driver installation program. Follow the installation instructions. You will only have to go through this process once.
Figure 20. InsideIR Main Screen at Program Launch If you wish to view the sample images now, click the plus sign to the right of the Samples folder to open it. Then double-click on the session name (My collection, in our example below). Figure 21. InsideIR Main Screen With Session Open July 1, 2003 - 33 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Downloading Images You are now ready to download the images you recorded in your ThermoView Ti30 imager. Locate the SYNC button in the docking station. Press the SYNC button once to begin the download process. SYNC button Figure 22. The SYNC button When synchronization completes, the following window appears: Once all data are downloaded, the information is saved into a temporary area where you may inspect the data before saving it to the disk.
Figure 23. Download Data Screen You can browse through the images by clicking and dragging the horizontal and vertical scroll bars. You cannot delete individual images. You must decide whether to save the entire collection or not. Click Save Data to save it. By clicking Cancel, the data is not saved to the disk. The following window appears when images are saved, signaling a successful operation: Click on OK.
Figure 24. Contents of Images Folder Your newly recorded images appear as thumbnails as they are downloaded into the program. Each set of images is in a fixed order so that you cannot rearrange the images. Use the scroll bars to browse through the thumbnail images. Setting the Imager Clock It is very important to set the Imager Clock in your ThermoView Ti30 imager because it records a time / date stamp with each stored image. This is important for meaningful reports and trending.
The following window appears: 2. Click the Date arrow to see the calendar. The following window appears: x Click on the side arrow buttons to change the current year / month x Click to select the day of the month. The following windows appears: July 1, 2003 - 37 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
x To set the current time, click on the hour and min (minute) boxes to enter time information. Use the 24-hour time format only. x Press the Set button to upload the information to the imager. Field USB Port In the event you need to download your images to a computer without the docking station, you may use the USB cable included with your ThermoView Ti30. Connect the cable to the Field USB port, under the display. (See Figure 25) Once the cable is connected, follow all steps previously described.
Figure 26. Viewing Thumbnail Images You can view a larger version of a single image by clicking on the thumbnail of the image you wish to view. When viewing a single image, you may move to the next or the previous image by clicking on the Previous Image or Next Image button on the left side of the screen (see Figure 27 below). July 1, 2003 - 39 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Figure 27. Viewing a Single Image July 1, 2003 - 40 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Chapter 4 Obtaining the Best Image The Importance of Focusing The focusing ability of the imager is similar to the one found on regular photographic cameras, and it is defined as the ability to adjust the optical system to capture the highest amount of infrared energy from the target, thus allowing the sharpest thermal image of the target to be displayed. Properly focusing the unit is of paramount importance for obtaining a crisp clear image.
Tip: When focusing an image, look for identifiable patterns or shapes on the object surface that can help establishing the best image definition. Objects contours, dividing lines or limits are particularly useful. Proper focusing is not only important to the image quality, but also greatly affects the accuracy of temperature measurements.
temperature value in the scene (MAX). The MIN and MAX values are displayed at the beginning and at the end of color scale. This mode does not require any other adjustment (other than properly focusing the unit). Automatic mode is recommended every time the user first starts looking at a given target since the temperature limits are unknown. This mode is also recommended when the user is looking for fairly large temperature differences (such as, looking for hot spots in electrical devices).
Graphically, it would look like this: The imager automatically calculates Level and Gain when switched from Automatic to Manual or Semi Automatic modes, thus providing a smooth and meaningful transition of the thermal boundaries of the scene. Once initially set by the ThermoView imager, Gain and Level can then be adjusted by the user in order to accommodate their specific requirements. Of course, in practical terms you can’t actually see the values for Gain and Level.
In Manual mode the user can adjust Gain and Level manually. Use this measurement mode when you need more freedom to define Level and Gain values. This mode provides the flexibility to bring both MIN and MAX values to the desired cut-off levels and to adjust the temperature interval to a minimum, thus maximizing color resolution. Using the Manual mode efficiently requires more experience with both thermal imaging techniques and specific knowledge of the equipment being inspected.
Chapter 5 Qualitative and Quantitative Temperature Measurements Most of the time thermal imager users are measuring apparent temperatures that are inextricably linked to qualitative inspections. Qualitative inspections focus on temperature differences as opposed to actual temperatures. The reason is that temperature differences are sufficient to indicate most abnormalities in electrical and mechanical equipments. In other words, qualitative inspections don’t aim at taking accurate temperature measurements.
D:S ratio: D / S = 90 The number “90” means that at a distance D equal to 1 meter the unit will measure a circle of diameter S equal to 1.1cm (1meter divided by 90); at distance D equal to 2 meters it will measure a circle with diameter S equal to 2.2cm and so on in a linear progression. Optical Diagram The optical diagram shows the graphical representation of the optical ratio.
Figure 30. Field of View Tip: When accuracy is critical make sure that the target is at least twice as large as the spot size. Environmental Conditions Watch for environmental conditions in the working area. Steam, dust, smoke, etc., can prevent accurate measurement by obstructing the path between the target and the unit's optics.
Emissivity Emissivity is the measure of an object's ability to emit infrared energy. Emitted infrared energy is exponentially proportional to the temperature of the object. Emissivity can have a value from 0 (shiny mirror, perfect reflector) to 1.0 (blackbody, perfect emitter). Most organic, painted, or oxidized surfaces have emissivity values close to 0.95. If you are performing qualitative inspections with your imager, leave the emissivity set at 1.0.
furnaces, or other heat sources) have a temperature much higher than that of the target. In these situations it is necessary to compensate for the reflected energy from those objects. Note: The Reflected Temperature Compensation (RTC) feature is disabled if the emissivity is set to 1.00. To set or change the RTC feature, complete the following steps: 1. You will need an infrared reflector. Take a piece of aluminum foil. Crumple and reflatten the foil and put it on a cardboard plate, shiny side up. 2.
Chapter 6 Organizing Your Data The ThermoView imager when used together with the InsideIR software provides a powerful way to organize and track maintenance data. Different groups of equipment can be inspected and data specific to different plant areas or departments can be individually named, saved, stored and retrieved in a straightforward fashion. Because all the records are electronic, they can be backed up and stored without fear of loss or fading of records.
Uploading Data to the Imager Click the Upload Setup Imager button on the InsideIR main screen to upload data to the ThermoView imager. This displays the following screen: Select the folder and session you want to upload and press Next. Figure 33. Uploading Data to Your ThermoView Ti30 Imager July 1, 2003 - 52 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
If you wish to change parameters for different locations such as location name, emissivity, reflected temperature compensation, low and high alarms, and comments, you can do so by right-clicking the thumbnail of the image you wish to edit, clicking Edit data in the pop-up menu, and changing the desired field(s). Figure 34.
Note 2: If you wish to restore the default parameters on the unit press the Restore button. By doing this all 100 locations on the imager will be restored with the factory parameters. These default parameters are: Location name: blank Emissivity: 1.00 RTC: OFF Low alarm: 0°C / 32° F High alarm: 250°C / 482° F Comments: blank July 1, 2003 - 54 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Chapter 7 Analyzing Your Data There are many ways to analyze your thermal data now that you have it downloaded and organized. After clicking on a thumbnail in the Main InsideIR screen, the data for that specific thermal image is displayed in one of four tabs: Image, Temperature Table, Profile, and Histogram. While each of these analytical tools possess unique qualities, they also share many features.
Figure 35. Sample Image at Original Scale Limits Figure 36. Sample Image After Increasing Scale Limits July 1, 2003 - 56 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Isotherms When the Isotherm radio button at the bottom of the Image screen is selected, the limit bar underneath the image shows the temperature range captured in the current thermal image. The red area on the limit bar indicates the range of temperatures displayed in red in the image. This range is also indicated on the temperature scale to the left of the image. To adjust the highlighted range, move the limit arrows on either edge of the limit bar, or the limit bar itself. Figure 37.
Figure 38. Sample Image After Adjusting Isotherm Level Additional Image Analysis Tools You can tile the window vertically or horizontally by selecting the appropriate choice under the Window menu. The tiled windows may then be resized by grabbing any corner of the window and dragging accordingly. Finally, you can further analyze the image under different Emissivity and Reflected Temperature conditions by changing those values on the left side of the screen.
Figure 39. The Temperature Table As mentioned above, this data can be saved as a .txt file, for import into a spreadsheet program for your own in-depth analysis. The Profile Tab There are two main components in the profile: an interactive radiometric thermal image on the top, and underneath it, a graph indicating the temperatures at the x and y axes of the cursor on thermal image. Click on any portion of the thermal image on the top for the exact temperature reading at that spot.
Figure 40. The Profile Tab The Histogram Tab The Histogram tab provides a summary of the pixel data presented on the previous screens. The histogram displays temperature values as either a percentage of the all temperature values captured in a given thermal scene, or by number of representative pixels in the thermal scene. To view a subset of the data, you may select Limits on the Images > Histogram menu, and enter the specific maximum and minimum temperatures for the data you are interested in graphing.
Figure 41. The Histogram Tab – Changing the Histogram Limits If you wish to use the chart or chart data in another program, you may select Copy Chart on the Images > Histogram menu. The information will be saved to your Windows clipboard, and can then be pasted into Word or Excel, using either the Paste or Paste Special command. The Menu Bar Now that you’re familiar with the concepts in the four tabs, you’ll quickly understand the choices offered on the menu bar. Each menu item is briefly described below.
ThermoView Imager Info Product-specific information about each ThermoView Ti30 imager you have used with a specific computer. This is useful when contacting the factory for service information. It is also useful to use the name of the individual units at the highest level in your directory structure, keeping all images stored by a single unit in the same folder. Exit Quits the application. Temperature Scale Fahrenheit Displays temperatures in the Fahrenheit scale.
Image Note: The Image menu items are only active when at least one image is selected. Export Image Allows you to save an image for use with another application in any of the following file formats: x x x x x x x x Note: .bmp .jpg .gif .png .tiff .wmf .exif .emf When using this option, only the image is saved—the data is not. Export Temperature Table Allows you to export the underlying pixel data from a thermal scene to a .
Copy Profile Chart Saves the chart from the Profile tab to your Windows clipboard, and can then be pasted into Word or Excel, using either the Paste or Paste Special command. Window Cascade Cascades all open windows. Tile Horizontal If you have more than one window open, this command will divide display them tiled horizontally. Regardless of the number of open windows, this command will allow you to resize a window by clicking and dragging any corner of the window.
Reporting Your Findings The ThermoView Ti30 imager provides report forms for you to use in reporting your findings. To generate a report, you must first select an image from a given location. Then select Image from the Menu Bar and choose Create Report from the drop down list. Figure 42. The Thermographic Report The report form is entitled “Thermographic Report.” Some data is filled in for you with known data from the image file so you don’t have to copy the information into the record.
Appendix A - Technical Reference Imager Accuracy Chart The following graph shows the measurement accuracy for a typical instrument over the measurement range of 0 – 250ºC. The heavy lines show the specified accuracy. 2 ERROR [C] 4 READING 0 2 4 0 50 100 SOURCE 150 TEMPERATURE 200 250 [C] Specification Measured Data July 1, 2003 - 66 - Version 1.0 i Tel: (01943) 602001- WWW.ISSLTD.CO.
Imager Reading Error vs Source D:S The following example uses the above Typical Reading Error vs. Source D/S graph: A 5" diameter source (Size = 5) at a Distance of 50" has D/S = 50/5 = 10. According to the above graph the imager would read less than 1% low in temperature (as shown by the dashed line) for this size target.
Table 1. Emissivity Values for Metals Material Aluminum Unoxidized Oxidized Alloy A3003, Oxidized Roughened Polished Brass Polished Burnished Oxidized Chromium Copper Polished Roughened Oxidized Electrical Terminal Blocks Gold Haynes Alloy Inconel Oxidized Sandblasted Electropolished Iron Oxidized Unoxidized Rusted Molten Iron, Cast Oxidized Unoxidized Molten Iron, Wrought Dull Lead Polished Rough Oxidized Magnesium Mercury Molybdenum July 1, 2003 1.0µm Emissivity 1.6µm 8-14µm 0.1-0.2 0.4 0.02-0.2 0.
Material Oxidized Unoxidized Monel (Ni-Cu) Nickel Oxidized Electrolytic Platinum Black Silver Steel Cold-Rolled Ground Sheet Polished Sheet Molten Oxidized Stainless Tin (Unoxidized) Titanium Polished Oxidized Tungsten Polished Zinc Oxidized Polished Table 2. 1.0µm Emissivity 1.6µm 8-14µm 0.5-0.9 0.25-0.35 0.3 0.4-0.9 0.1-0.35 0.2-0.6 0.2-0.6 0.1 0.1-0.14 0.8-0.9 0.2-0.4 0.4-0.7 0.1-0.3 0.2-0.5 n.r. n.r. n.r. 0.95 0.02 0.9 n.r. 0.8-0.9 n.r. 0.35 0.35 0.8-0.9 0.35 0.25 0.8-0.9 n.r. 0.25 0.
Material “Gob” Gravel Gypsum Ice Limestone Paint (non-Al.) Paper (any color) Plastic (opaque, over 20 mils) Rubber Sand Snow Soil Water Wood, Natural 1.0µm Emissivity 1.6µm n.r. n.r. n.r. n.r. n.r. — n.r. n.r. n.r. n.r. n.r. n.r. n.r. n.r. 0.9 0.95 0.4-0.97 — 0.4-0.98 0.9-0.95 0.95 0.95 0.9 0.9 — — — 0.9-0.95 8-14µm n.r. 0.95 0.8-0.95 0.98 0.9-0.95 0.95 0.95 0.95 0.9 0.9 0.9-0.98 0.93 To optimize surface temperature measurement accuracy consider the following: 1.
Appendix B – Infrared Theory Q&A Q. Why use noncontact infrared thermometers? A. Noncontact infrared (IR) thermometers use infrared technology to quickly and conveniently measure the surface temperature of objects. They provide fast temperature readings without physically touching the object. The temperature is shown on the LCD display.
Q. How to assure accurate temperature measurement? A. A solid understanding of infrared technology and its principles lies behind accurate temperature measurement. When the temperature is measured by a noncontact device the IR energy emitted from the measured object passes through the optical system of the thermometer or thermal imager and is converted to an electrical signal at the detector. This signal is then displayed as a temperature reading and/ or thermal image.
temperature of a shiny object you can compensate by covering the surface to be measured with masking tape or flat black paint. Allow time for the tape or paint to reach the same temperature as the material underneath. Measure the temperature of the taped or painted surface. That is the true temperature. Distance to spot ratio The optical system of an infrared thermometer collects the infrared energy from a circular measurement spot and focuses it on the detector.
that the target is at least twice as large as the spot size. Q. How to take temperature measurement? A. To take a temperature measurement, just point the unit at the object you wish to measure. Be sure to consider distance-to-spot size ratio and field of view. There are important things to keep in mind while using infrared thermometers: 1. Measure surface temperature only. The IR thermometer cannot measure internal temperatures. 2. Do not take temperature measurement through glass.
Glossary Absolute Zero The temperature (0 Kelvin) of an object defined by the theoretical condition where the object has zero energy.
Background Temperature Temperature behind and surrounding the target, as viewed from the instrument. Blackbody A perfect emitter; an object that absorbs all the radiant energy incident on it at all wavelengths and reflects and transmits none. A surface with emissivity of unity (1.00). °C (Celsius) Temperature scale based on 0° (zero degrees) as the freezing point of water, and 100° as the vaporization point of water, at standard pressure. qC qF 32 1.
Display Resolution The level of precision to which a temperature value can be displayed, usually expressed in degrees or tenths of degrees. Drift The change in instrument indication over a long period of time, not caused by external influences on the device (per the ASTM standard test method E 1256-88). EMC Electro-Magnetic Compatibility is the resistance to electrical signal disturbances within IR thermometers.
Focus Point (or Distance) The distance from the instrument where the optical resolution is greatest. Full Scale The maximum of the temperature range or output signal. Full Scale Accuracy A convention for expressing the accuracy as percentage of an instrument’s (highest) fullscale temperature. Gray Body A radiating object whose emissivity is in constant ratio (not unity) at all wavelengths to that of a blackbody at the same temperature, and does not transmit infrared energy. HAL High Alarm.
LAL Low Alarm. Units with this feature can sound an alarm when they sense that a user-defined low temperature has been reached. Laser Single or dual lasers are used in some units for aiming and/or locating the optimum temperature measurement point. LOC Location. Units with the data-logging feature store data in numbered locations, which can be recalled and reviewed on the display when necessary. Loop A cycle of operations within a selected mode.
Non-Gray Body A radiating object that is partly transparent to infrared (transmits infrared energy at certain wavelengths); also called Colored Bodies. Glass and plastic films are examples of non-gray bodies. Optical Pyrometer A system that, by comparing a source whose temperature is to be measured to a standardized source of illumination (usually com-pared to the human eye), determines the temperature of the former source.
Reflected Temperature Compensation Correction feature used to achieve greater accuracy when, due to a high uniform background temperature, IR energy is reflected off the target into the instrument. If the background temperature is known the instrument reading can be corrected by using this feature. Targets that have low emissivities will reflect energy from nearby objects, which may result is inaccurate readings.
Spectral Response The wavelength region in which the IR Thermometer is sensitive. Spot The diameter of the area on the target where the temperature determination is made. The spot is defined by the circular aperture at the target that allows typically 90% of the IR energy to be collected by the instrument, as compared with the 100% spot diameter which is defined by the IR energy collected from a very large target.
Temperature Resolution The minimum simulated or actual change in target temperature that gives a usable change in output and/or indication (per the ASTM standard test method E 1256-88). Thermal Shock A short-term error in accuracy caused by a transient ambient temperature change. The instrument recovers from its accuracy error when it comes back into equilibrium with the new ambient conditions. Time Constant The time it takes for a sensing element to respond to 63.2% of a step change at the tar-get.
