EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: daisizhou on May 18, 2022, 01:24:27 am
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Saw on Youtube a French author made a FLUKE 8920A multimeter online adapter.
Due to the language, I don't know much about the author's description, and I still don't know much about some details after using the translation software.
Only "see pictures and talk",I made the author's PCB and some chips are in transit.
I don't know if there are any friends with the same hobbies.hope to share
https://www.youtube.com/watch?v=o9qQ8JtDIsM&list=PLfiqNnhpCsNspEonkDP8q8BwR6GYaR8f2 (https://www.youtube.com/watch?v=o9qQ8JtDIsM&list=PLfiqNnhpCsNspEonkDP8q8BwR6GYaR8f2)
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im native french, he read the analog port on the back panel and thru the internal connector j501 he read the ranges
i think it will be a multi part video ?? he talks about designing an mcu board with an external 12bit or more adc to do the job, an 10 adc is not sufficient ........
and in the zip you have the schematics and the executable software
seems well designed for an hobby project :-+ :-+
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Yes, this is a series of at least 5 or more.
Unfortunately, I can't understand the detailed introduction, and the author's subtitles are also in French.After I use translation software to translate, the meaning seems to be deviated.
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The added circuit in the schematics is to read the Fluke thru an added mcu+adc circuit, not to control it ......
It read the ranges modes and as i wrote the back panel rear voltage, the circuit has some software compensation/calibration
you have the arduino code
you read theses ranges, and you have an manual or automatic mode
1 : 2 mV
2: 20 mV
3: 200 mV
4 : 2 V
5 : 20 V
6 : 200 V
7 : 700 V
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Do you only need to connect J1 (7-pin) to the J501 interface in the 8920A?
I don't know how the J23 interface is connected to the 8920A.
J23 is a reserved interface, no need to connect?
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you need both
j23 will give the voltage / read to the input of the pcb interface / project ADC as you see in the schematic (zipped file)
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Is it connected like this? But J23 I don't know how to connect
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I only had a short look (and don't understand french). There seems to be no electric isolation between the DMM input and the output output side, at least up to the arduino. One should have an isolated USB, likely as isolared UART and than a UART/USB adater.
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Is it connected like this? But J23 I don't know how to connect
you have to put a wire between the rear plugs and the project pcb ??? two if you add the ground,
as i've written YOU need to read the banana plugs on the back panel since its an analog value of what is measured on the fluke display
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Do you mean I connect it like the picture below?
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seems like it ...
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ok, i followed this scheme to assemble the chip, the chip is in transit.
grateful :-+
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The 8920A manual mentions an IEEE-488 interface available as a factory option, but I can't find any details anywhere.
It'd completely change the project, but it looks like you could read the digital data from the DMM using the J601 connector, along with range info from J501. J601 output is BCD, with strobe lines. I don't see any connections that would allow control of the DMM. I'd guess the IEEE-488 interface is talk only?
And as others have mentioned, galvanic isolation is a good idea. The option for a frequency counter incorporated a pair of transformers for isolation.
(I don't have an 8920A, so don't have any reason to complete this project. However, I've done similar interfaces in the past for other manufacturer's equipment...)