Last week we discussed how to adjust level and span manually. Sometimes this can lead to a lot of “button pushing!” It is not a big deal – just one of life’s little aggravations. Thankfully, many models of Fluke imagers have a very helpful solution: 1-TIME AUTO ADJUST.
How does 1-TIME AUTO ADJUST work?
When the imager is in the MANUAL mode, you can press the F3 button and instantly get a 1-TIME AUTO ADJUST. This feature works just like AUTO but with one very important difference: it only works when you press the F3 button. The image is then adjusted based on whatever is in the field of view at that moment. The warmest temperature defines the upper limit of the SPAN and the lowest temperature defines the lower limit.
When does 1-TIME AUTO ADJUST work best?
As I indicated last week, I often find it most useful to be in the MANUAL adjust mode. But it is also great to have the option of quickly re-adjusting the SPAN. When?
• If I need to quickly adjust to the right SPAN and LEVEL to look at wall insulation, I will walk right up to the wall and press F3. The image immediate adjusts a very tight SPAN at a LEVEL appropriate to the wall temperatures.
• When I don’t understand how to best adjust an image for a particular situation, for example an energized dry transformer, I can press F3 and quickly get a different view; it may not be perfect but it will help me understand what further manual adjustments I need to make to get a perfect image.
• When I’m conducting a functionality check of my imager by viewing the face of a person, I can move close to their face, press F3 and quickly end up with an image adjusted with a narrow SPAN for a LEVEL appropriate to facial temperatures, just as I did with the wall.
What are the limitations of 1-TIME AUTO ADJUST?
Just as is the case with using AUTO, if you have extraneous hot or cold areas in the image, 1-TIME AUTO ADJUST will take them into account as it adjusts, resulting in a poor quality image.
How can I use 1-TIME AUTO ADJUST successfully?
Ensure that objects with extraneous hot and cold temperatures are not in the image when you press F3. As an example, rather than pressing F3 while viewing a wall with a cold window and warm radiator, point the imager at the floor or move closer to the wall so you are viewing only the wall. When you then press F3, you’ll get an adjustment that is much closer to what you want.
Of course you can always make a fine adjustment by going into MANUAL or, after downloading the image in Smartview. If you have it, try 1-TIME AUTO ADJUST and learn what it can and cannot do. You’ll quickly learn when to use it to great advantage.
Next week we’ll move on to the basic, but very important topic of what is your point of view. This will not be a political discussion, but one of how to gain the best thermal image!
John Snell—The Snell Group, a Fluke Thermal Imaging Blog content partner