Fluke 289 owners tell .... help please - Page 1
Forum section: electronics / testgear

author: megik
author_rank: Newbie
timestamp: May 20, 2014, 12:22:28 pm
content: Be a new device fluke 289 but with an incomprehensible feature should be so or not?At the limit of measurement mADC shyupah shorted or not instead of 0.000 shows 0.000-0.002-0.003That is periodically jumpsThis is fine with this device?in the video too sdes readings jump but only 0.001Sorry for my bad English

author: megik
author_rank: Newbie
timestamp: May 21, 2014, 08:16:36 am
content: so that neither the Owner fluke 287/289 mozhut nothing to say about this?

author: jpb
author_rank: Super Contributor
timestamp: May 21, 2014, 09:44:06 am
content: In the lowest (50mV) range the specified error is 0.05% + 20, this means that when measuring zero Volts the last two digits could be between -20 and +20 and it still be in spec. Your meter is only hovering around 2 or 3 counts which is well within the specification.20 digits is only 20 microVolts, practically all the DMMs (portable) I have looked at have a specification the same e.g. Brymen BM869 (20), Gossen MetraHIT Ultra (25), Hioki DT4282 (25) so this is par for the course as golfers would put it!As a comparison, 5 1/2 digit bench multimeters in the lowest range seem to be about 7 or 8 microVolts and 6 1/2 digit bench multimeters are around 3.5 microVolts but these have heated references so 20 microVolts in a handheld run on batteries is reasonable.

author: han
author_rank: Frequent Contributor
timestamp: May 21, 2014, 09:53:23 am
content: I have see 4 of 5fluke 289 having voltage residual reading at loZ switch (several volt, since i forget the exact value).and the seller say it's normal.

author: megik
author_rank: Newbie
timestamp: May 21, 2014, 02:08:52 pm
content: talking about maDC (A) rather than NOT mvDCin such a situation what your indicators???

author: electr_peter
author_rank: Unknown
timestamp: May 21, 2014, 05:48:23 pm
content: Quote from: han on May 21, 2014, 09:53:23 amActually, poor accuracy is a "feature" of a low Z mode - low Z uses maximum voltage range by default + semi-variable input resistance + TRMS converter. TRMS converters do not like to be run at low voltage range (less than 10%). Add all these up and you have seemingly massive offset on AC for low Z (DC low Z still should be ~0.0V), but it is not a problem (unless it is like 100V - that is a malfunction). One other thing - you cannot "null out" offset at AC, only for DC.See another thread on Agilent U1272A and low Zhttps://www.eevblog.com/forum/testgear/u1272a-low-z-in-off-mode/msg445024/#msg445024Regarding jumping numbers on mA DC range with shorted pins - 289 has very low minimal resolution and this allows to show up noise at low measurement levels. Read 289 manual and specifications carefully - you should expect some % error and bias error on all ranges.Try to not measure quantity with too large range (for example, do not try 1 mA signal measurement on Amps range).

author: jpb
author_rank: Super Contributor
timestamp: May 21, 2014, 05:58:09 pm
content: Quote from: megik on May 21, 2014, 02:08:52 pmSorry misread the OP but it doesn't make much difference. On the DCmA range the spec is 10 counts on the 50mA range so 3 to 4 counts is still well within it.(This is around 10 microAmps.)

author: megik
author_rank: Newbie
timestamp: May 22, 2014, 06:55:49 pm
content: I want to explain a bit in the video for an example of what I meanIf you want to understand whether the problem is in my device so I write here and there and then there are many people who have the same 289/287The bottom line is that my copy has some offset on the measurement maDC even dimension and it is always there regardless of indication measurements used dmmcheck plusOn other devices stable readings .Watch the video , who can say that on this occasionWould like to know exactly from the owners 289/287And a new device until it is possible to contact the dealer , but I would argue that is not so.The fact that I do not live in USA and I just pick up and go directly to a fluke not workTanks!

author: LA7SJA
author_rank: Regular Contributor
timestamp: May 24, 2014, 12:02:21 pm
content: My Fluke 287 works the same, and it's just back from calibration. And I tested with my dmmcheck plus with the same result as you. So I think this behavior is normal for the Fluke 28X and it is within specs. I just phoned a Fluke rep. who confirmed that this was normal.JFG

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 24, 2014, 02:54:17 pm
content: You can download the calibration manual and refer to the performance test section.There are no checks regarding the shorted inputs on the mA ranges. You can only verify the offsets on the 50mV and 500 ohm ranges. The 50mV range should read +/- 0.020 and the 500 ohm range should read +/- 0.10. You will need a good connection with a short wire. Test leads will probably not be the best option.If those are within spec, I wouldn't worry about the offsets on the 50mA range, especially since it appears the 1mA test input reads as expected.As others have noted, your meter appears to be functioning properly and is probably well within specs on that range.