Noncontact Infrared Thermometers

Trip · Post by **Trip** » Sun Jan 25, 2004 3:40 pm

there was a mention of these here and I was curious which ones people recommended in these forums.

info.

Actually, it seems like there is a lot of confusion about these things. I'd be interested in reading a discussion of the science behind them as well.

fmah · Post by **fmah** » Sun Jan 25, 2004 5:28 pm

Well one thing to realize is that most of these units, except higher end ones, assume a fixed emissivity. I see normally it is assumed to be 0.95. Which means it is calibrated for measuring temperature on a surface such as a black anodized body. Measuring other items will be less accurate unless their emissivity is close to that value.

Bluefront · Post by **Bluefront** » Sun Jan 25, 2004 5:40 pm

Here's one I use. Snap-on brand about $100 a few years ago. It has an LCD screen and is very accurate for computer use.

Trip · Post by **Trip** » Sun Jan 25, 2004 6:54 pm

fmah, emissivity seems to be really important, heh, and confusing. It sounds like what you hear with digital cameras, "it's a waste of your money to buy a cheap one" and also that even some of the pricey ones are bad.

Bluefront, do you know about the emissivity of yours?

how to read emissivity

apparently one doesn't want to measure total emissivity, only infrared emissivity.

cpemma · Post by **cpemma** » Mon Jan 26, 2004 11:18 am

The problem is, clean metal surfaces, like plain aluminium, have very low emissivity, and text-book references won't agree when it comes to subtleties.

And unless you know the exact value a reading will be way out. You really need to calibrate them on a similar surface/object that's sat in an oven at a known temperature.

Bluefront · Post by **Bluefront** » Mon Jan 26, 2004 2:47 pm

Trip....don't know. Mine is not adjustable anyway. I have checked it against many known surface temperatures and it is very accurate. It has a laser pointer to indicate the exact spot you're measuring. I use it for many applications other than computers. You can run the laser over the top of a video card and find the hot spots/chips easily. I can measure the Northbridge without a specific sensor on it....many uses.

Laser Beam

lm · Post by lm » Mon Jan 26, 2004 2:52 pm

How do you know it's accurate? It might be very sensitive but does not mean the result is correct?

Bluefront · Post by **Bluefront** » Mon Jan 26, 2004 3:02 pm

for instance...you can measure an auto head temperature right at the car's head temp sensor. If the car's computer registers 180F, this device will always be within a few degrees.... plenty good enough. Or measure the side of your furnace digital thermostat, checks the same. It's accurate.

trodas · Post by **trodas** » Fri Jan 30, 2004 1:14 pm

Well, the precision is interesting. With this one:
http://www.professionalequipment.com/xq ... efault.htm
I find there a maximal +-2 degrees shift between -40 and +310 degrees, witch is IMHO acceptable for my desires of temperature measuring

Anybody having good experience with these things? I would like to buy this one online - if i managed to find anyone in US, to witch address i can send it together with something to compensate the price of re-sending it back to me

Likely after measuring everything into the whole house

I looking for this DeltaTRACK one, because very similar mode its used by Toms labs for temperature measuring, and when im novice with something, i feel that's best learn from professionals

However Toms labs using the more costy version (420 bucks, bloody hell, that im not planing to spendt on temperature measuring

), but after reading the specs become pretty clear, that this low-cost version have the exactly same sensor and precision, just the targes focusing is worser - 1:8 cannot compare to 1:33

However the price - with posting price and little bonus for the villing friend - get only little over 100 bucks, and not 4x more

Can anyone explain me, how the focusing will affect the measuring???

lindalewis · Post by **lindalewis** » Tue Aug 18, 2009 2:35 am

I have noticed that many of you use thermometers with alarms for overnight cooks. I was wondering which models you use?