Products > Test Equipment

Tonghui TH2827C LCR meter

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nctnico:
Then again, making the test fixture will be very problematic at several MHz.

IMHO a better approach would be to use a network analyser to examine frequency dependant behaviour.

mawyatt:
From the views at ADI it appears the PCBs have direct 4 BNCs for the respective LCR Kelvin connections at the proper spacing and orientation, altho wouldn't put much faith in the Kelvin leads supplied*. The external fixtures could be the same as we use with the Hioki IM3536 (Tonghui TH26048A and TH26009B) which are good to at least 13MHz according to Tonghui specs, so one can place some confidence in those specs, and why we use them with the Hioki IM3536 to 8MHz.

The cheap SMD LCR meter fixtures we have appear to be direct copies of the Tonghui TH26008A which is speced to 120MHz, so these might be OK to use.

If you check some R&S LCR meters/fixtures they "appear" to be rebrands of Tonghui, so speaks highly of Tonghui equipment. The stuff we have is excellent and not surprised if R&S chose to rebrand some items.

*Wouldn't consider Kelvin Clips leads for anything above ~100KHz for serious measurements, the quality Tonghui TH26011CS we have are speced only to 100KHz.

If we had any serious software skills we might consider the ADI ADMX2001, as it seems to be a fun project to just "see" how good this could be.

We'll be happy to make LCR device measurements with our TH2830 and IM3536 plus fixtures for device comparisons for anyone that wants.

Best,

Dagobert1:
I have been working with the ADMX2001B since January. The ADMX2001 is operated via the serial interface using a Raspberry Pi 5 with 8 GB and an LCD touchscreen. The Raspberry Pi is running the latest Ubuntu 23.10. I develop the software under Qt6 in C++. In the project wiki on github I have added a few screenshots of the ADMX2001 Software and an installation guide for the tools required for development: https://github.com/Nordlicht123/ADMX2001_LCR_Meter

The sources of the software are not yet available. As soon as the software has reached a certain level of maturity, I will make the software available.

The ADMX2001b recognizes 7 impedance measuring ranges that are used for the autorange. Each of these ranges must be calibrated. I am currently in the process of writing the software for calibration over the entire frequency range. At the same time, I have found someone who can measure long-term stable reference capacitances over the frequency range of 0-10 MHz. This data is read into my software and then serves as calibration values, which are used for calibration with the real reference capacitance.

ch_scr:

--- Quote from: Dagobert1 on July 07, 2024, 11:10:10 pm ---I have been working with the ADMX2001B since January. The ADMX2001 is operated via the serial interface using a Raspberry Pi 5 with 8 GB and an LCD touchscreen. The Raspberry Pi is running the latest Ubuntu 23.10. I develop the software under Qt6 in C++. [...]

--- End quote ---
Pretty nice project (and nice to see someone tackling it at all), but a RasPi 5 and full-blown Ubuntu seem "a bit" over the top for "just" a user interface.
"Complexity is cheap" I guess (I'm aware this allows for speedy development and interoperability).
I guess on the upside, the application could run on a "normal" PC with a standard Ubuntu install (or in a VM), with no need for any extra HW aside the LCR meter itself?

While the high-vis readout and preset buttons seems like they would do nice on a small-ish touch LCD already,
the rest of the UI still seems more appropriate to a "mouse & keyboard" interface and "PC-size" screen?
I'd suspect making one UI fit both the "touch only small screen" and "PC app for general use" without unwieldy compromises is quite impossible.
(e.g. the touch UI might need an on-screen Numpad for number entry, everything bigger, ...)
Which poses the question if there could be 2 "UI presets"?
IMHO if you go build a box with RasPi and touch LCD, it's much more effort to also have physical buttons on there and it makes more sense to "just" use bigger touch LCD
in the first place and implement all UI there?
I'd suspect most would just use the application for convenient communication with the device from "a computer already there" and fewer would build the "dedicated bench box"?

Dagobert1:
Of course, you could also operate the ADMX2001B with a PC using an adapter from USB to RS232. The software can certainly be adapted so that communication can also take place via a virtual COM port. However, I would like to have a stand-alone device in the lab and connect to the device via Ethernet if necessary. As far as operation is concerned, I'm taking the pragmatic route and I've already tried out the possibilities offered by Qt for the main measurement page. I first had to make the calibration page mouse and keyboard operable, because the calibration is rarely needed during normal operation and I absolutely need the calibration data to calculate the measured values. It is also possible that functions such as calibration are only implemented via the web interface. For me, the measurement currently has absolute priority. What the Gui will ultimately look like will emerge over time. I would also like to implement the "Onscreens Numpad" window, I already had the idea. I have tried this in the pictures with the different outputs of measurement types. In the implementation, this is nothing more than an input field realized by buttons. What is actually written on the buttons is irrelevant.

The main task of a measuring device is high-performance and accurate measurement. All these things in the direction of the GUI are implemented quickly and are therefore currently less important. The high-performance communication to the ADMX2001 and especially the calibration is very complex and has already taken me many weeks of work.

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