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Blog #029 – Your THERMOGRAPHY COMFORT LEVEL –Should I use manual or auto mode for span adjustment?

If your infrared camera gives you the option of manual mode or automatic mode for span adjustment you might wonder which mode is best and why?  Let’s talk about the difference in these modes.  The manual mode locks the span bar so that the span doesn’t change as you scan the room and view a variety of temperatures (cold areas, hot areas, etc).  If you put your infrared camera in the automatic mode you will notice that the span bar changes as the temperatures change.  Why?  In the auto mode the camera will automatically adjust the span bar to the hottest and coldest temperatures in the FOV (field of view).  To me there is an advantage to locking the span bar in manual mode most of the time.  Let’s say that I’m investigating for moisture issues.  So, I spray a little water on the wall and fan it so as to create evaporative cooling.  The temperature of the wet area drops a few degrees.  I adjust the span bar so as to best identify this anomaly.  In the following example I’ve set a 17° span so as to identify the moisture issues.  The top of the span is 86° F and the bottom is 69° F.  Notice what happens when I change from manual mode to automatic mode (see second image).  The span bar changes from a 17° span to a 148° span and you can barely see the moisture issue.  This demonstrates the problem with leaving the camera in the auto mode.

Taken with Fluke Ti32 in manual span adjustment mode

Taken with Fluke Ti32 in manual span adjustment mode

Taken with Fluke Ti32 in auto span adjustment mode

Taken with Fluke Ti32 in auto span adjustment mode

When might you use the auto span adjustment mode?  Some of us use it in the initial setting of the span before locking the span bar.  For example, when I spray a little water on the wall and fan it to create evaporative cooling I can point my infrared camera at just the wet area in the auto mode and allow the camera to set the span according to the highest and lowest temperatures.  You would want to be careful that you don’t have any extreme temperatures in your FOV (field of view), like the examples above.  And then I can switch over to manual mode.  That’s one of my favorite features of the Fluke TiR1 and Fluke Ti32 (or TiR32) infrared cameras.  You can push the F1 key on the front of the camera and switch back and forth from auto mode to manual mode to auto mode.  It’s a very, very convenient feature.

Hopefully you now feel more comfortable in the use of the manual and automatic mode of span bar adjustments. 




How’s your comfort level in thermography?
(The above comments represent my opinion).

Rod Hoff / Restoration Consultants Inc
Thermography Instructor / IR camera sales
3284 Ramos Circle, Sacramento CA 95827
toll free 888-617-3266 ext 301
fax 916-736-1134

Provider of Fluke TiS, TiR, TiR1, Ti, Ti25, TiR27, Ti27, TiR29, Ti29, TiR32, Ti32, TiR3, and TiR4 infrared cameras.


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About infrarod

Rod Hoff is a Thermographer and instructor with Restoration Consultants, Inc. He teaches a two-day IR class in moisture and building envelope investigations. A graduate from Florida State University, with a degree in education, he received his formal training in Thermography from Snell Infrared and Restoration Consultants, Inc.

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