Tektronix DMM4040 сalibration - Page 1
Forum section: electronics / testgear

author: Taimer81
author_rank: Regular Contributor
timestamp: April 03, 2025, 06:06:25 pm
content: Hello.I have a Tektronix DMM4040. Can you please tell me if it is possible to perform the calibration by myself, or do I need to use special paid software for this?Thank you.https://photos.app.goo.gl/BSNaNFcTmQkkn8s16

author: bdunham7
author_rank: Super Contributor
timestamp: April 03, 2025, 06:27:03 pm
content: That is essentially the same meter a the Fluke 8845A and I've attached the calibration manual for that. The one thing that might be different is the calibration password, I've no idea on that IDK if Tek has also release the manual for this. If the procedure in this manual doesn't work, then perhaps you can contact Tektronix and see if they'll provide the password. Or perhaps someone knows it or perhaps it is "FLUKE884X".Now as for actually calibrating it, do you actually have reference sources good enough for that?

author: Taimer81
author_rank: Regular Contributor
timestamp: April 03, 2025, 08:42:52 pm
content: Thank you.I looked and found a similar product from Tekronix. They completely match except for the passwords.Tell me, please. I did not understand the instructions. All the steps must be done strictly sequentially or can a selected step be skipped?

author: Taimer81
author_rank: Regular Contributor
timestamp: April 03, 2025, 08:49:29 pm
content: Judging by the data, the deviation of all measurements is 0.01%. If possible, it would be easier to multiply by 0.9999 for all ranges and the measurements will then be accurate.

author: Taimer81
author_rank: Regular Contributor
timestamp: April 04, 2025, 03:46:26 pm
content: I noticed a special feature in this mode. The multimeter displays seven fullcharacters.

author: Taimer81
author_rank: Regular Contributor
timestamp: April 04, 2025, 04:21:46 pm
content: I figured it out . The calibration password turned out to be the standard . I can calibrate each step individually, no need to follow the sequence. However, I think that the problem may not be in the calibration, but in the dust . I've seen a lot of dust inside . I think this may be affected by dust, because multiplication to get the correct data is the same as 0 .9999 . The error may also occur in other ranges.

author: RomDump
author_rank: Regular Contributor
timestamp: April 06, 2025, 04:39:37 am
content: Quote from: Taimer81 on April 04, 2025, 04:21:46 pmI assume the standard meaning "PITBULL"?

author: Taimer81
author_rank: Regular Contributor
timestamp: April 06, 2025, 07:00:28 am
content: Quote from: RomDump on April 06, 2025, 04:39:37 amNo ))))

author: Taimer81
author_rank: Regular Contributor
timestamp: April 06, 2025, 02:44:39 pm
content: Large deviation.

author: J-R
author_rank: Super Contributor
timestamp: April 07, 2025, 02:37:31 am
content: I have concerns with regard to how you are approaching these discrepancies. The Fluke 87V and the Agilent? calibrator have nothing to offer here since they are not in the same class as the DMM4040.The 510 calibrator also cannot be used in this context since its best capability in the 1-11V range at the absolute best is +/- 0.55mV. (There is also a percentage listed, but I can't tell from the translation if it's percentage of reading or percent of range, but that just makes the accuracy worse anyway.)If you are adjusting DMMs that come to you without proper external calibration standards and procedures, you may easily end up in a position where you do not know which end is up.

author: boggis the cat
author_rank: Regular Contributor
timestamp: April 07, 2025, 04:39:07 am
content: The instruments that you are using have worse specifications than the DMM4040. While it is statistically likely that some deviation on the DMM4040 is present (as you have a source and two measures that roughly agree) it isn’t possible to know with any certainty how great that deviation really is.I suggest that you obtain one of the cheap ‘voltage reference’ boxes that various people sell on AliExpress. Make sure that it comes with recorded values for the voltages. I have bought two, and both aligned well with results form our reference equipment in the lab.

author: J-R
author_rank: Super Contributor
timestamp: April 07, 2025, 05:31:25 am
content: From another thread, we know he has one of the cheap references. But if he's been using that to calibrate/adjust everything else in his possession, then he's in unknown territory.

author: boggis the cat
author_rank: Regular Contributor
timestamp: April 07, 2025, 09:35:53 am
content: Sure. However, those references, if the seller did the correct thing and verified them properly, are still going to be an order of magnitude better than using unknown source(s) and meters.

author: J-R
author_rank: Super Contributor
timestamp: April 07, 2025, 10:36:15 pm
content: There are a lot of ifs on those cheap references...But also, things can go wrong even with very expensive references/calibrators/DMMs, so that is where proper calibration procedures and checks come in to play. A hobbyists can get away with taking some shortcuts, but not like this.I would want to have at least two externally calibrated 6.5 digit DMMs along with their calibration data, or one calibrated DMM plus one reference (both with data). You need the calibration data because there can be a significant amount of slop with the specifications. On both of my calibrated 6.5 digit DMMs, I have the data that shows they are good to within a few counts at the very least significant digit. If I ONLY had a calibration sticker but no data, things could be 10 times worse and still "pass" the calibration procedure. Without the calibration data, I'd think you'd need at least a 7.5 or even 8.5 digit DMM to properly calibrate a 6.5 digit DMM.

author: Taimer81
author_rank: Regular Contributor
timestamp: April 08, 2025, 08:15:44 am
content: )

author: Taimer81
author_rank: Regular Contributor
timestamp: April 08, 2025, 08:17:12 am
content: 2