How to test upper limit on IR thermometer?

An ordinary incandescent light bulb with a dimmer switch, glowing almost red in the dark (not toaster orange or yellow) or an electric stove top hotplate.

You'll need to convert from kelvin to Fahrenheit to read the chart.

Get a large soldering iron tip on a temperature controlled iron. Use that. Get close.

greg

Do you have this process available? What does the thermometer read?

It usually is. That and the selection of the components.

Solder melts at about 370degF. Paper bursts into flame spontaneously at about 451degF. Lead (tire weights, until the greenies kill these) melts at about

621degF. You can sprinkle a little carbon (charcoal) dust on the liquid metals to increase emissivity to the point your handheld can read them.

David A. Smith

Did you get this from the movie, or the book? ;-P

Cheers! Rich

acy

ge?

Some iron alloys demagnetize (Curie-Weisz susceptibility law) at known temperatures, and kilns are calibrated with little cones that deform at known temperatures. The lightbulb idea is good BUT only if your full field is the filament of the bulb (I've seen bulbs with a ribbon filament,

100W at 6V, that might work). Don't look at color, but use a voltmeter and ammeter, the resistance of a tungsten filament has a known temperature dependence (measure it cold, measure current/voltage when hot, the resistance change is a known function of temperature).

If you have the luxury of a laboratory, make a black body (box with a hole in it), with a good (thermocouple) thermometer, and put it into a kiln. Open the kiln peephole and take the temperature with the IR unit.

A couple things:

1. The wavelengths used do not pass through glass and largely do not pass through quartz.
2. IR non-contact have a minimum source size requirement to read accurately. Objects less than 10-15 mm wide may not come up accurately.

However, an electric hot plate should push an IR non-contact thermometer past reading 500 F, since they get to about 1400-1500 F.

- Don Klipstein ( snipped-for-privacy@misty.com)

You can test the firmware limit by pointing at a stovetop electric element.

acy

ge?

Lead melts at 327.5 =B0C (that's 621.5 =B0F for Imperials).

Tom Davidson Richmond, VA

Oh right, I'll remember to put your hand next to a light bulb, I'll wear a glove.

and largely do not pass

Oh right, I'll remember quartz halogen bulbs don't get hot and call the men in white coats to change your headlights.

Oh right, I'll remember if cigarettes aren't too small to glow red, then at least sparks from flint on steel aren't hot enough to reach the flashpoint of petroleum spirit or methane or butane and ignite.

Mine doesn't get much above 212 F, but then I can cook and don't like steam in my soup.

The radiant heat you feel from lightbulbs consists of two parts:

1. The portion from the filament - entirely (or nearly enough so) of wavelengths too short to be in the range of an IR thermometer, because the bulb material is opaque (or nearly enough so) to them.
2. The portion radiated by the bulb material - which is what an IR thermometer will sense.

- Don Klipstein ( snipped-for-privacy@misty.com)

The unit will usually switch to "off scale" indicator of some kind. With a voltmeter, it is like "OV" for overvoltage. OT would be over temp, but not all that intuitive, so it would probably flash off scale or something.

The way you check it is by finding someone with, or renting an IR thermometer that will read that high, take a reading, and see what your meter does at the same time. A high temp thermocouple will get you in the ball park as well.

I doubt it will continue to display much over (or under) its calibrated range. Since they do not guarantee calibration and damage can even occur to a resistor bolometer (likely is that), they usually switch the display to an error message.

There are spot focused units available. The chiropracty profession uses (years ago) them to examine spinal column temps on a one inch focus unit, calibrated from ice to just over human body temperature, about 30° to 120° F. It has a cone shaped nose, and about a half inch opening, and usually has a little arm with a rolling ball on the end that is used to maintain a one inch distance from a surface (like flesh or a vertebral 'high spot').

Depends. If it is a coil shaped heater, just like on a stove, then yes. If it is a "pan" or inverted pan, which is heated from beneath (by a coil shaped heater), it usually passes through a heat spreader of sorts between the heater and the pan. This makes for a much more uniform temperature, but it would also be a bit lower. They usually do not get to the "red hot" temp., so... what... maybe 1000° F? Better to check it with a higher range device.

A nice, hot teflon skillet is pretty damned evenly heated right after it comes of the stove (not the sides).

Pretty weird how the bottom does not radiate much heat toward your cheek, but the teflon side does... a lot. Pretty good lesson in emissivity.

Solder, which is what most electronics industry soldering irons melt, melts at right around 500° F (for 63/37).

The soldering iron is pretty good. The calibrate a tip temp, one has an iron which is a bit hotter, so if it says 700°, the actual heating element is likely a couple tens of degrees hotter. The tip taper is the reason.

That is why I like Metcal. They sense the temp when you soak away heat during an operation, and they fire it right back up within a second or two. Five seconds on power up. Two second basic recovery.

... is called radiant heat.

A couple of things. When someone snips what I write then I snip whatever they write and sometimes I'll replace what I write, in order to give them another chance at being sensible. This doesn't always work, there are many bigots who want to dominate a conversation by snipping because they can't really heckle in any other way. Those I then plonk.

Oh right, I'll remember to put your hand next to a light bulb, I'll wear a glove.

and largely do not pass

Oh right, I'll remember quartz halogen bulbs don't get hot and call the men in white coats to change your headlights.

Oh right, I'll remember if cigarettes aren't too small to glow red, then at least sparks from flint on steel aren't hot enough to reach the flashpoint of petroleum spirit or methane or butane and ignite.

Mine doesn't get much above 212 F, but then I can cook and don't like steam in my soup.

Moron. The hot plate gets a lot hotter without a pot or pan of food to dissipate the heat. If it only went to 212 F it wouldn't get the food hot for hours, or days. All it would do is warm it up enough to let it spoil faster.

--
You can't have a sense of humor, if you have no sense!

More important, what temperature destroys the sensor?

--
You can't have a sense of humor, if you have no sense!

Fuckhead. I said "doesn't get much above".

Now piss off, idiot. *plonk*

Do not reply to this generic message, it was automatically generated; you have been kill-filed, either for being boringly stupid, repetitive, unfunny, ineducable, repeatedly posting politics, religion or off-topic subjects to a sci. newsgroup, attempting cheapskate free advertising for profit, because you are a troll, simply insane or any combination or permutation of the aforementioned reasons; any reply will go unread.

Boringly stupid is the most common cause of kill-filing, but because this message is generic the other reasons have been included. You are left to decide which is most applicable to you.

There is no appeal, I have despotic power over whom I will electronically admit into my home and you do not qualify as a reasonable person I would wish to converse with or even poke fun at. Some weirdoes are not kill- filed, they amuse me and I retain them for their entertainment value as I would any chicken with two heads, either one of which enables the dumb bird to scratch dirt, step back, look down, step forward to the same spot and repeat the process eternally.

This should not trouble you, many of those plonked find it a blessing that they are not required to think and can persist in their bigotry or crackpot theories without challenge.

You have the right to free speech, I have the right not to listen. The kill-file will be cleared annually with spring cleaning or whenever I purchase a new computer or hard drive.

I hope you find this explanation is satisfactory but even if you don't, damnly my frank, I don't give a dear. Have a nice day.

On Fri, 14 Aug 2009 02:46:19 -0700, Michael A. Terrell wrote (in article ):

These are *non-contact* sensors. How can pointing it at an IR source from a distance damage it?

It is going to depend on the sensor.

Eyeballs are non-contact sensors, try staring at the sun.

--
Jim Pennino

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