Anyone interested in making a FLUKE 8920A adapter? - Page 1
Forum section: electronics / testgear

author: daisizhou
author_rank: Super Contributor
timestamp: May 18, 2022, 01:24:27 am
content: 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

author: coromonadalix
author_rank: Super Contributor
timestamp: May 18, 2022, 02:06:13 am
content: im native french, he read the analog port on the back panel and thru the internal connector j501 he read the rangesi 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 softwareseems well designed for an hobby project

author: daisizhou
author_rank: Super Contributor
timestamp: May 18, 2022, 02:33:04 am
content: 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.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 18, 2022, 10:56:26 am
content: 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/calibrationyou have the arduino codeyou read theses ranges, and you have an manual or automatic mode1 : 2 mV2: 20 mV3: 200 mV4 : 2 V5 : 20 V6 : 200 V7 : 700 V

author: daisizhou
author_rank: Super Contributor
timestamp: May 18, 2022, 11:26:05 am
content: 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?

author: coromonadalix
author_rank: Super Contributor
timestamp: May 19, 2022, 01:53:29 am
content: you need bothj23 will give the voltage / read to the input of the pcb interface / project ADC as you see in the schematic (zipped file)

author: daisizhou
author_rank: Super Contributor
timestamp: May 19, 2022, 02:30:16 am
content: Is it connected like this? But J23 I don't know how to connect

author: Kleinstein
author_rank: Super Contributor
timestamp: May 19, 2022, 04:41:51 am
content: 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.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 19, 2022, 08:34:52 am
content: Quote from: daisizhou on May 19, 2022, 02:30:16 amyou have to put a wire between the rear plugs and the project pcbtwo 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

author: daisizhou
author_rank: Super Contributor
timestamp: May 19, 2022, 09:57:38 am
content: Do you mean I connect it like the picture below?

author: coromonadalix
author_rank: Super Contributor
timestamp: May 20, 2022, 01:06:22 am
content: seems like it ...

author: daisizhou
author_rank: Super Contributor
timestamp: May 20, 2022, 01:26:03 am
content: ok, i followed this scheme to assemble the chip, the chip is in transit.grateful

author: pigrew
author_rank: Frequent Contributor
timestamp: May 20, 2022, 02:17:09 am
content: 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...)