I just bought a Fluke 64 MAX IR Thermometer for measuring temps on my Shelby, and have a question. The laser dot does not appear to be centered in the measurement area. EX: If I'm 10 feet from an object, I get the most accurate reading when the laser dot is pointed 6" to the left of the object. If I'm only 5 feet away, that error cuts in half - to 3".I thought that dot was supposed to be in the center of the measurement area - not off to the side.
The first unit I received did this, so I sent it back for replacement. But the replacement is doing exactly the same thing.
I like Fluke for their reputation, sturdiness, and accuracy. So this is disappointing.
Am I expecting too much? Or should I send this unit back and try another brand?
Thanks,
Steve Sloan
I have used an IR thermometer in the past and not had that problem. I was 12" or less from the area I was measuring. I would try a little closer and see. When I measured the temperature of the thermostat housing, I was about 6 to 10 inches away and the dot was exactly where it was pointed.
Think of IR thermometers as working on a "cone". The further from the object you are, the wider the area it will try to average.
I have two IR guns, both cheaper than the fluke, and I have never tried to measure something more than a foot away. Five foot away, you are measuring an area maybe a foot in diameter- is that useful information?
This may help:
Fluke IR temperature guns have different distance-to-spot (D:S) ratios depending on the model, ranging from 8:1 for general-purpose tools to 60:1 for high-temperature industrial units. A higher ratio allows for accurate measurements from further away, while lower ratios are designed for closer, smaller targets.
Common Fluke IR Gun Distance-to-Spot Ratios
Fluke 59 MAX: 8:1 (best for close-range, general maintenance).
Fluke 62 MAX: 10:1 (suitable for electrical panels and HVAC).
Fluke 64 MAX: 20:1 (offers better precision from a distance).
Fluke 566/568: 50:1 (ideal for higher, smaller targets).
Fluke 572-2: 60:1 (designed for long-distance, high-temperature industrial use).
The smaller the target, the closer you must be to ensure the sensor only reads the target, not the background.
I can't attest to the Flukes IR NCT accuracy as I don't own one. I have several Fluke meters and the are excellent tools. I do have a Raytek Autopro IR NCT that is about 20 years old an it has excellent accuracy. It has dual lasers with a 8"focal point. Just tested its accuracy at 8" vs 8', reads same temp at both distances.
Do note that the commonly available, that is something other than what the U.S. Military or N.A.S.A. might have, "I.R. Temperature Guns" are often prone to interpreting the values being sought improperly; as this is a referred value that can be influenced by, among other things, the specific items' emissivity, surface material, including color & finish texture, and then there's also interference from the environmental factors. :o
Also realize, that even "if" accurate, this value is only as of the actual surface, aka not the "core temperature". So for example, if "shooting" the radiator core (tube & fins), that which is being presented is the "surface temperature", not the actual water temperature within; and as with something like this, the difference "should" be significant! ;)
Scott.