:: need a recoomendation for good temp measurement :: - Page 1
Forum section: electronics / testgear

author: 3roomlab
author_rank: Frequent Contributor
timestamp: February 19, 2014, 11:42:24 am
content: hello fellows ...im in need of a recommendation for a fairly accurate infrared thermometer (or even contact type meter), i am considering to buy a fluke 62. however id like to ask all fellows out here, what do you use, how accurate is your IR thrmometer, etc ... and is there anything else worth buying other than a fluke 62.main uses, to check heater element temperature (below 400C), to troubleshoot/check electronics (rarely), to calibrate arduino stuff temperature measurement projects (may need accuracy to 0.1C, i wonder if IR meters have such accuracy?)i had the chance to use an old fluke before (cant rem the model), and although it wasnt a very highly accurate experience, it sure was very convenient to just point and read in an instant. and i also understand that contact type of measurements requires contact surfaces to be consistent, otherwise, it will never be accurate as well. so in terms of consistently vs accuracy etc ... im wondering should i get fluke 62? or something else ...thanks everyone for any insight.

author: Fsck
author_rank: Super Contributor
timestamp: February 20, 2014, 10:15:37 pm
content: I've never personally seen a +/- 0.1C or less error guaranteed in an IR meter over a decent range (there are probably some medical ones supertuned to body temp +/- 10C with that kind of accuracy), I'm not sure why you need an IR that accurate.the best IR meters I've seen for the range you're talking about tend to be ~ +/- 1.x C and they're pricey as hell.these are their guaranteed specs of course. it's entirely possible and quite likely that a high quality IR-therm will give you much better measurements, but it's not guaranteed.I have a cheapy Rosewill 25$ IR, it's proven to be almost always < (+/- 1C), but it's specced to something like +/- 3% (averaged over range), around the range of [10C,35C] in comparison to every other therm I have.If you need desperately <.1C accuracy, stick with SPRTs/PRTs or just RTDs. And yes, it requires contact surface to be consistent. the easy (and sort of tediously overkill) is to just stick a bunch of flat PRTs across the surface you want.IR-therms have a similar problem with emissivity of the surface.Short version: Fluke 62 is excellent for the price, but still a +/- [1.5% or 1.5C, whichever is greater]. Use RTDs to achieve close to +/- 0.1C or very tightly specced PRTs to actually hit or exceed it. (specs generalized from memory, could be wrong about non platinum RTDs)

author: Noise Floor
author_rank: Regular Contributor
timestamp: June 26, 2014, 10:57:26 pm
content: I have a Fluke 62 Max +, its a great unit and very robust (handles falls well). However it definitely does not have the accuracy you are looking for. If you can come down on your accuracy requirement, I think the Fluke 62 would be a great unit for you and allow you to avoid having to do contact measurements.

author: jpb
author_rank: Super Contributor
timestamp: June 27, 2014, 09:04:31 am
content: The other thing with IR thermometers is that you need to know the emissivity of the object you're looking at to get accurate readings :http://www.optotherm.com/emiss-table.htmSome IR thermometers are use a fixed "average" value whilst others allow you to set it.A way around this is to attach something black say to what you're measuring to get a precisely known value but if you're doing that you might as well use a contact method.

author: mzzj
author_rank: Super Contributor
timestamp: June 27, 2014, 10:09:11 pm
content: Fluke 62 and especially 62 mini are just cr*p.570 series and VT02 Visual IR Thermometer are only fluke IR-meters that I would trust better than 1,5 K570 and VT02 typically give you roughly 0,2K short-term repeatability.Contact thermometers are another sort of buggers, cant expect too much accuracy.

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2014, 12:07:29 am
content: I prefer just using K type thermocouples and delta Vbe temperature probes but had considered picking up a Fluke 62 used until mzzj's comment.

author: ixfd64
author_rank: Frequent Contributor
timestamp: June 28, 2014, 12:10:39 am
content: How about the Amprobe IR thermometers?http://www.amprobe.com/Amprobe/usen/Products/category.htm?Category=AMP_HVAC_INFTHEI've never used them before, but they have pretty good reviews.