Aneng AN8002 video review - Page 1
Forum section: electronics / testgear

author: PA4TIM
author_rank: Super Contributor
timestamp: August 03, 2017, 10:17:15 am
content: I bought a AN8002 and checked it's calibration followed by a short teardown. This little thing turned out to be spot-on.https://youtu.be/0-cxAv41L1M

author: PA4TIM
author_rank: Super Contributor
timestamp: August 04, 2017, 07:26:07 pm
content: I did some more testing today. Forget the TRMS. It measures sinewaves accurate upto 1 kHz. It measures AC coupled so it can not measure AC with a DC offset like for instance a 60Hz 0V to 5V squarewave. You need an AC+DC TRMS meter for that, It can measure a true AC 100Hz squarwave with a 49% to 51% dutycycle. So it is TRMS. You can probably measure a distorted 50 of 60Hz mains AC signal. But I am curious if it can handle the AC current of a SMPS. (indirect via a shunt or clamp for safety) I have a beautiful analog KEW clampmeter in my vintage meter collection. That is only usable for pure sinewave currents.TRMS without specs for crestfactor and bandwith is not more as a marketing spec.

author: floobydust
author_rank: Super Contributor
timestamp: August 04, 2017, 07:47:34 pm
content: DMM IC app note: "Before calculating its AC value, it will pass through HPF (High Pass Filter) to remove DC." So the RMS-calculating block is AC coupled.To do true-RMS (including DC offset) you need the square-root function. The MCU can't do it, very computationally intensive.

author: glarsson
author_rank: Frequent Contributor
timestamp: August 04, 2017, 08:25:06 pm
content: Quote from: floobydust on August 04, 2017, 07:47:34 pmSo computationally intensive you have to do it by hand or use a 40 year old pocket calculator.https://en.wikipedia.org/wiki/Methods_of_computing_square_roots

author: Mark Hennessy
author_rank: Frequent Contributor
timestamp: August 04, 2017, 10:22:14 pm
content: In my tests, it does true RMS not quite as well as a Fluke 8920A, but just as well as a Fluke 87V.The tests were done at 100Hz, as the spec states that "other waveforms exceed 200Hz are for reference only" (sic).I haven't seen a spec for crest factor as yet, but whatever it is for a Fluke 87V, this one does at least the same.If there isn't a specific "AC+DC" mode - which is generally something that is reserved for the more expensive meters - then the measurement is always AC coupled. At least that's the case for every meter I've seen so far; perhaps there's an exception, but I haven't stumbled across it yet... Personally, I don't have a problem with a meter set to AC telling me the amplitude of theAC componentof a signal. The meter can tell me the DC and the AC separately, and I can calculate the AC+DC value myself if I need to:https://en.wikipedia.org/wiki/Root_mean_square#In_electrical_engineeringI don't understand why so many people question the true RMS aspect of these meters - why would they lie about something that is trivially easy to check?

author: PA4TIM
author_rank: Super Contributor
timestamp: August 04, 2017, 10:45:31 pm
content: I was to quick. I used signals that are real TRMS and true life but a bit extreme and I would not use a DMM for those myself.I know about how to calculate trms and indeed most meters are AC coupled (I have 2 TRMS meters that are only AC coupled, I have 4 that are AC+DC ;-) )I now took a DMM current clamp with 1 kHz BW. Measured the 50Hz current from a charger. A 9Vpp and 0,64Vrms signa on the scopel. A Tek scope currentprobe gave the same signal shape. Then used the clamp on my Brymen BM869 and the Aneng and both gave the same value. So it is TRMS and usable (for 50Hz, have not tested higher frequency)QuoteStrange, my manual states only: 40Hz to 1 kHz, for voltage and current and I can not find the 200Hz statement .Someone on a dutch forum has one too and his manual states a 400Hz BW for voltage and 200Hz for current. (https://www.circuitsonline.net/forum/view/message/1928961#1928961)QuoteDo you believe the CAT data of this sort meters too ?

author: Mark Hennessy
author_rank: Frequent Contributor
timestamp: August 04, 2017, 11:00:11 pm
content: Quote from: PA4TIM on August 04, 2017, 10:45:31 pmIt's right at the bottom of page 2 of my printed manual.I had a quick search, and found a Zotek ZT102 manual -https://www.eevblog.com/forum/testgear/an8008-us-%2419-10000count-1uv-0-01ua-0-01ohm-resolution-meter/?action=dlattach;attach=332480- and this appears to be lacking the note. So it seems that there's more than 1 version of the manual floating around out there...

author: floobydust
author_rank: Super Contributor
timestamp: August 04, 2017, 11:21:55 pm
content: DM0660 DMM IC Datasheet specs are:AC Measurement Bandwidth:Sine wave 0.5% error: 20-1.5kHzSine wave -3dB: 6kHzSquare wave 0.5% error: 100HzTriangle wave 0.5% error: 1.2kHzThe DMM IC (similar to a PIC18) chugs along at 4MHz and has a 8x8 multiply instruction. No divide instruction. Very basic. Real-time RMS calc would be too much at high rez.There is a true-RMS math block in hardware, but as the tests show it discards the DC component.I don't expect much DC mixed with my AC.

author: PA4TIM
author_rank: Super Contributor
timestamp: August 04, 2017, 11:51:57 pm
content: 6th try, scan of my manual.I can not upload them as attachment, so I put them on my site insteadhttp://www.pa4tim.nl/?p=5949

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 05, 2017, 06:44:48 am
content: hi. my AN8002 just arrived. i bought it mainly for its temperature function (beside its probe accessories that i will use for my UNI-T clip probe). to validate reading of my VC99 multimeter. but they are contradicting, when VC99 read 27degC, the AN8002 read 30degC. do you have way to verify temperature reading? i'm not sure which one is faulty VC99 or the AN8002...

author: sleemanj
author_rank: Super Contributor
timestamp: August 05, 2017, 07:10:10 am
content: Human body temperature - stick the probe under your tongue, should stabilise to 36-37 degrees, assuming you're not sickIce water, about 0The resolution of temperature reading in these cheap multimeters is only to the degree, and the tolerance is a bit uncertain (what exactly does 1.0%+5 counts mean when you are only showing whole degrees at double digits...), but I just did a tongue test with my VC99, RM102 (8002) and ADM02 and they all agreed within a degree.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 05, 2017, 08:24:33 am
content: Quote from: sleemanj on August 05, 2017, 07:10:10 amthanks. i did tongue test... VC99 = 32degC, AN8002 = 36degC.ice test VC99 = 0degC, AN8002 = 1degCboiling water test VC99 = 90degC, AN8002 = 93degCso i guess AN8002 is closer to reality, my VC99 (Vici) is off...

author: PA4TIM
author_rank: Super Contributor
timestamp: August 05, 2017, 08:42:11 am
content: Quote from: Mechatrommer on August 05, 2017, 06:44:48 amYou buy a 12 euro meter to calibrate the temperature function of an other meter ?A good temperature meter has a real thermocouple input (those flat connectors) with a good cold junction compensation. A good thermocouple alone cost more then the Aneng. Calibration grade TC's cost more as the VC99.Your idea is a bit like buying this meter to validate the voltage reading of a 6,5 digit benchmeterTo calibrate a thermocouple or a multimeter that uses one really good , they use things like a drywell . A device that can make temperatures from f.i. -20 to +120 C. There is often a 3cm hole in the top to enter the thermocouple. But if you use it like that you get not the good values. (It can easy be 2 degrees off) So a 10k costing device will be as usable as the aneng if used not the proper way. To get good results they enter an insert with a hole that is a snug fit for a thermocouple and sometimes they fill up the rest of the space so no air can come in. And that way you can get it within 0,1 degree or better. To get it better as 0,1 they use calibration grade thermometers instead of the one build in the drywell.You need to calibrate both the TC and the meter.If have 10 TC's you have a big chance they all give a different temperature. The worst TC I have is over 10 degrees wrong, the best one I have is 0,2 degrees off . I have the luxury of having acces to a lot of calibration gear. I have a simple calibrator my self (Beamex TC303) but I repair calibration gear and 2 of my customers are into temperature calibration so if I get a drywell here for repair I use it to check my TC's (they sometimes include a calibration thermometer so I can check it after repair) You can use it to check your meter and the TC as a combination. But then you do not know if the meter or TC is wrong. So if you want to swap TC's you need a calibration thermometer with TC input or a very good voltmeter. The latter often lacks a good TC input but the Anengs TC has banana jacks so you will never get it better as 1 or 2 dregrees.You can do a simple test. Put the meter in the refrigerator and let the TC stick out but put it in something with a high thermal mass like a bottle of water so airstream has no influence. First measure the water with the meter outside the fridge, let it stabilize for 10 minutes or so (the connectors and DMM busses also have a seebeck effect.Then put the meter in the fridge with the TC and bottle outside the fridge. A very good meter with cold junction compensation will not change the readings.For those interested:http://schneiderelectronicsrepair.nl/?p=467a teardown of a simple TIC based drywell that had 3 bad TIC's (peltier elements)You can calibrate the meter itself with a voltage. There are tables that specify the voltage thermocouples generate. (the TC from the aneng is a K-type) But you need a very stable source and good high resolution calibrated multimeter to check the voltage or use a voltage calibrator. The signals are mV's. That way you now if the meter is correct. You can check the TC too with a voltage measurement. But you need a very good DMM for that tooYou can use things like ice-water but that is to check the TC and DMM as a combination. You do in that case not know if the meters read different, if it is the TC or meter.The Aneng reads a temperature without the TC so it seems to have a some form of CJC.They probably calibrate the meter with a voltage.About body temp, that will not work very well unless you know your body temp. Mine is very low (around 35 degrees C) My wife bought an ear thermometer. Used it on my son but it did read very low, she tested it on me, same reading. So back to the shop but the replacement did the same so I took a meter to check and it turned both our temperature was in the 35 degrees. We never had a fever, When I was really sick my temperature was around 37 degrees and you do not measure it if your not sick. . Now I know that is for me like 39 degrees for most people

author: Fungus
author_rank: Super Contributor
timestamp: August 05, 2017, 08:48:50 am
content: Quote from: PA4TIM on August 05, 2017, 08:42:11 amI don't think he bought it for "calibration", he just ended up with two temperature measurement devices and decided to compare the results. Seems perfectly natural to me.It also demonstrates my theory that two meters are always better than one, no matter how expensive the "one" was.

author: kalel
author_rank: Frequent Contributor
timestamp: August 05, 2017, 08:52:17 am
content: Quote from: Fungus on August 05, 2017, 08:48:50 amFor sure, but when they differ and you're not sure which one is right, what do you do? Do you take both values as wrong, take one value as right, or take the average?

author: PA4TIM
author_rank: Super Contributor
timestamp: August 05, 2017, 09:01:30 am
content: QuoteQuoteThen I interpreted that wrong .

author: MosherIV
author_rank: Super Contributor
timestamp: August 05, 2017, 09:04:54 am
content: QuoteBear in mind that K type thermocouples are only accurate to +/-1°C, then you have the inaccuracies of the meter on top.Try checking 2 temperature points - melting ice (should be 0°C) and boiling water (100°C)Melting ice should be small ice in water, let it sit until condensation forms on container then measure.Boiling water is trickier than it sounds, purity of water and altitude play a big part!Try both set points and see what they come out at. Melting ice is the easier one to do. This should give you a good idea of what the absolute offset of each dmm/thermocouple.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 05, 2017, 12:21:32 pm
content: Quote from: Fungus on August 05, 2017, 08:48:50 amdittoQuote from: kalel on August 05, 2017, 08:52:17 ambuy the 3rd (cheap) meterany candidate?but ice and boiling water + body temperature seems reasonable and adequte for laymens' daily life, imho..

author: mtdoc
author_rank: Super Contributor
timestamp: August 05, 2017, 06:26:22 pm
content: Nice video review PA4TIM!Quote from: PA4TIM on August 05, 2017, 08:42:11 amConsider that your "ear thermometer" is the equivalent of a $5 multimeter - would you make the same conclusions about voltage measurements based on that?While there is some variability in normal human body temperature - 35 degrees C is far outside of that (See table below). Ear (tympanic membrane) IR thermometers tend to read a bit low but even so, no one has body temperature of 35 degrees C without being borderline hypothermic.The human body does a very good job of maintaining body temperature under most conditions. There is some diurnal variation but unless someone is ill, body temperature will remain very constant over a short time period. The trick is getting an accurate measurement.An old fashioned glass mercury thermometer (inserted rectally!) is probably the best one can do outside of specialized esophageal thermometers used in hospital or research settings. If sticking a thermometer up ones bum is too troublesome, under the tongue is the next best. You can use this as a good, inexpensive temperature standard to check your digital thermometers..

author: kalel
author_rank: Frequent Contributor
timestamp: August 06, 2017, 05:56:42 am
content: Quote from: mtdoc on August 05, 2017, 06:26:22 pmInteresting field, any idea why the oral range is so large? Comparing to all others, it seems to stand out.

author: Fungus
author_rank: Super Contributor
timestamp: August 06, 2017, 11:16:25 am
content: Quote from: kalel on August 05, 2017, 08:52:17 amThen youinvestigateand find out which one is right.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: August 06, 2017, 04:44:03 pm
content: Quote from: mtdoc on August 05, 2017, 06:26:22 pmThink there must be real good explanation (simple terms, common knowledge) in store when one eventually gets caught by some family member

author: SeanB
author_rank: Super Contributor
timestamp: August 06, 2017, 05:46:28 pm
content: Simple reason oral range is so big is that the blood supply has a larger area to dissipate heat before it reaches the inner mucosa of the mouth, plus cooling from inhaled and exhaled breath absorbing heat.Interesting fact about axillary temperature is that some early sea rescue radios during the WWII period ( and for a while after as well) used a local oscillator that had crystal control, with the crystal and the oscillator being designed for optimum stability and precise frequency at 36C, and this was contained in a small container that was designed to be held in your armpit for 5 minutes before you activated the batteries on the unit to cause it to transmit a very narrow high frequency beacon for the search and rescue to home in on. No receive capability, and a water activated battery inside that would run the transmitter for a few days at low use rate, you had a clockwork timer that provided the pulsed carrier.

author: Sakunne
author_rank: Newbie
timestamp: December 24, 2017, 06:33:37 pm
content: To test the temperature measure temp of boiling water, it should be 100 deg C in sea lavel.My AN8002 shows 96 deg. is ther any way to recalibrate it

author: HKJ
author_rank: Super Contributor
timestamp: December 24, 2017, 11:06:28 pm
content: Quote from: Sakunne on December 24, 2017, 06:33:37 pmVery often the problem with thermocouplers is that people do not know how they work: They do not measure temperature, only temperature difference and that difference is between the connector (Details depends on construction) and the tip. The meter then add the ambient temperature to that.You will only get precise readings if the internal temperature sensor in the meter has the same temperature as the connector!

author: Fungus
author_rank: Super Contributor
timestamp: December 25, 2017, 07:37:47 am
content: Quote from: HKJ on December 24, 2017, 11:06:28 pmIf only there was a video:

author: PA4TIM
author_rank: Super Contributor
timestamp: December 25, 2017, 08:56:24 am
content: Quote from: mtdoc on August 05, 2017, 06:26:22 pmConsider that your "ear thermometer" is the equivalent of a $5 multimeter - would you make the same conclusions about voltage measurements based on that?While there is some variability in normal human body temperature - 35 degrees C is far outside of that (See table below). Ear (tympanic membrane) IR thermometers tend to read a bit low but even so, no one has body temperature of 35 degrees C without being borderline hypothermic.The human body does a very good job of maintaining body temperature under most conditions. There is some diurnal variation but unless someone is ill, body temperature will remain very constant over a short time period. The trick is getting an accurate measurement.An old fashioned glass mercury thermometer (inserted rectally!) is probably the best one can do outside of specialized esophageal thermometers used in hospital or research settings. If sticking a thermometer up ones bum is too troublesome, under the tongue is the next best. You can use this as a good, inexpensive temperature standard to check your digital thermometers..A bit late but thanks for the info. It is not 35 degrees, I wrote "in the 35 degree's". If I remember well it was around 35,8. It was later verified by a doctor. (I have nerve system and spine problems)Yesterday I read your commend and took my Aneng that is always here in the livingroom to measure in my mouth using the original TC with the crappy connectors. Without the meter showed 19 degrees that could be correct. With the TC it wandered between 14 and 16 degrees. In my mouth it measured 30 - 31 degrees. So the TC is not great. If I do not forget I will test both meter and TC with my temperature calibrator. But 2 crappy bananas will even degrade a calibration grade TC