Calibration of Fluke 15/17 B+ ("PLUS") - Page 1
Forum section: electronics / testgear

author: DG5SAY
author_rank: Contributor
timestamp: April 07, 2015, 02:06:41 pm
content: Hi,has anyone an idea to calibrate a Fluke 15 or 17 B+?Not the "B"-series without the "+", I mean the "B+"!They are completely different with the "B" (without "+"), there are NO trimpot inside, but contacts to connect a software based calibration unit. One of these contacts are labeled "CAL".Ralf.

author: DG5SAY
author_rank: Contributor
timestamp: July 10, 2016, 07:34:11 pm
content: Yes!I can´t believe it!FLUKE published the calibration manual for the "+" models:http://assets.fluke.com/manuals/15BPlus_cmeng0000.pdf

author: retiredcaps
author_rank: Super Contributor
timestamp: July 10, 2016, 09:48:06 pm
content: Quote from: DG5SAY on July 10, 2016, 07:34:11 pmDo you have the equipment to calibrate/adjust your 15B+ now? History athttps://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg809723/#msg809723

author: DG5SAY
author_rank: Contributor
timestamp: July 11, 2016, 11:01:52 am
content: Do you have the equipment to calibrate/adjust your 15B+ now? History athttps://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg809723/#msg809723You don´t need a "special Fluke calibrator". A stable voltage source, checked with an other (calibrated?) DMM is good enough for a 15B+.

author: boggis the cat
author_rank: Regular Contributor
timestamp: July 11, 2016, 12:02:06 pm
content: If you want to adjust the multimeter, then you'll have to be able to source the exact specified voltage, current, and resistance values.I haven't checked the 17B+, but for AC voltage it is typical for Fluke to specify 60 Hz and a high frequency (e.g. 20 kHz to 10 kHz for the Fluke 87 V) as parameters. If those aren't very accurate (either voltage or frequency) then you'll pass the inaccuracy to the multimeter -- i.e. mis-calibrate it. The signal also has to be sinusoidal and fairly clean from noise. Purpose-built calibrators (from Fluke or other providers) are the usual approach.On the other hand, just checking the accuracy against a second known multimeter (ideally, recently calibrated with full data) only requires reasonably stable signals from any convenient source.

author: Fungus
author_rank: Super Contributor
timestamp: July 11, 2016, 10:32:11 pm
content: Quote from: DG5SAY on July 11, 2016, 11:01:52 amMaybe you'd like to walk us through the procedure after reading that document.I've got a super-stable voltage source. It's connected to the meter. Now what...?

author: DG5SAY
author_rank: Contributor
timestamp: July 12, 2016, 01:50:18 pm
content: Quote from: Fungus on July 11, 2016, 10:32:11 pmOK, no problem:1. remove the calibration sticker2. connect a external 3 V battery to the battery contacts3. turn the rotary switch to "VDC" (if you wish to recalibrate VDC, of course)4. connect the meter to your "super-stable voltage source" with exactly 3.000 VDC and wait a few seconds to stabilize5. short on the PCB the contacts "CAL1" and "WP6" (there are under the cal-sticker you have removed) until you hear a short "beep" and the high voltage mark appears on the display6. push the -button to confirm7. turn off the multimeterThat´s it!Repeat this steps for VAC (or other functions, see table 7 in the calibration manual) similar.It works fine on my 15B+

author: Fungus
author_rank: Super Contributor
timestamp: July 12, 2016, 02:01:51 pm
content: Quote from: DG5SAY on July 12, 2016, 01:50:18 pmAh, I mes-read that bit.Yeah, it should work. All you need is the super-stable references.

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: December 15, 2016, 07:09:50 pm
content: Quote from: Fungus on July 12, 2016, 02:01:51 pmWould a MAX6126AASA41+ and a 12-bit DAC controlled by an Arduino be good enough to create a 3.000V reference for calibrating a 17B+ (VDC only) ? Or should there be a much more precise DAC (>= 16-bit) ?I just found out that my 17B+ is about 2% off, which has been enough to steer me on the wrong direction when working with it.I discovered that because I couldn't figure out what was wrong with my project and decided to double check everything with a Fluke 117 and a Mastech MS8260E, both of which gave me the same reading, confirming that my circuit and software were correct. The Fluke 117 came with a factory calibration certificate, while the 17B+ didn't. Both were bought in Sept. 2015.

author: Fungus
author_rank: Super Contributor
timestamp: December 15, 2016, 07:21:56 pm
content: Quote from: AlxDroidDev on December 15, 2016, 07:09:50 pmWhat's the DAC for?Just get a MAX6126AASA30+ (3V reference).5 bucks from mouser.(or ask MAXIM for a free sample, you never know...)

author: retiredcaps
author_rank: Super Contributor
timestamp: December 15, 2016, 07:27:41 pm
content: Quote from: AlxDroidDev on December 15, 2016, 07:09:50 pmI think one other member reported that his 17B+ was out of calibration right from the start, but never sent it back to the ebay seller due to high shipping costs.

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: December 16, 2016, 01:14:38 am
content: Quote from: Fungus on December 15, 2016, 07:21:56 pmTo trim the 4.096V of the MAX6126xx41 to 3.000V.I already have a MAX6126AASA41+, that I got for my programmable load neverending project, and a few DACs of different precisions.I don't work with VAC, so I have no way of telling if my 17B+ is calibrated on that. I can tell, however, that it's temperature measurement are also quite off: I just built a breadboard circuit to with a LM335AZ and a DS1631+ to compare against the it, and the DMM was reading >4 degress above ambiente temperature (actual: 18.5C, read: 22.7C).A couple hours ago I wrote Fluke asking for quote on a calibration for the 17B+, because I suspect all of its readings are out of spec.

author: Fungus
author_rank: Super Contributor
timestamp: December 16, 2016, 09:47:56 am
content: Quote from: AlxDroidDev on December 16, 2016, 01:14:38 amSeems like a weird way to do it.Still,anythingthat's better than 2% accuracy will be an improvement right now.In theory you could do it with an LM317 and a potentiometer. Connect it to both the calibration input of the 17B+ and the voltage measurement of the Fluke 117 (and the Mastech if you want). Dial 3.00V and press 'calibrate'.

author: AndyBollo
author_rank: Newbie
timestamp: November 19, 2017, 09:46:34 pm
content: Even an $8 USD multimeter just out of the box performs better than the FLUKE 17B+. Shame on you Fluke! Respect to the fuke 17B+, Amprobe was very superior in all tests! Does not matter if the 17B+ was made for the asian market, carry the brand "Fluke" and should shows quality and accuracy!!!!!

author: HalFET
author_rank: Frequent Contributor
timestamp: November 19, 2017, 10:19:25 pm
content: Quote from: AndyBollo on November 19, 2017, 09:46:34 pmActually that one is still within call if I recall the 17B+ specs: 0.5% on DC volts, so 20 mV error on 5V is quite acceptable...Additionally, there's a reason we sayprecisioninstrument, and not accurate instrument! Precision means it's repeatable and the measurements are tightly grouped, offsets are acceptable as long as they are repeatable. It's a common mistake to assume that a good multimeter will always indicate the exact value, if you want that you better pull out the big bucks and invest in a high-end HP or Keithley with a LTZ1000 or LM399 reference (each of which will cost more than your Chinese multimeter), and be prepared to leave them on 24/7, and dish out the 800 bucks it costs each year to get it calibrated. And even those will drift and give an error, but instead of ppt it'll be ppm there. I suppose you could always get yourself a Josephson standard and a Caesium beam standard to drive it.I check my 17B+ against my calibrated Keithley 2001 every time I start using it on the bench, and haven't noticed any real drift on the 17B+ yet.

author: AndyBollo
author_rank: Newbie
timestamp: November 19, 2017, 11:59:47 pm
content: Quote from: HalFET on November 19, 2017, 10:19:25 pmSorry for expect a better accuracy out-of-the-box than cheaper models of multimeters, at least I would expect that from a Fluke (It does not matter if it is a low-end product or where it was manufactured)

author: HalFET
author_rank: Frequent Contributor
timestamp: November 20, 2017, 06:11:02 am
content: The accuracy is within tolerance, difference is that the Fluke has input protection, will stay within cal if you throw it in your toolbox for a year, and can survive a drop left and right.