Design a New Precision LCR Tweezers with Much Lower Cost 【Shannon Tweezers ST42】

[giosif]

Yes, we have tried to make the short cal result in zero, but we did not have much motivation to finish this optimization.
Cause the 20milliOhms is the limitation of the tips contraction and ST42, and we have discussed one option is to use a "<30milliOhms" to replace the test result,
This way to show the result to users may be more reasonable.

Do you have many test cases that need a smaller range, which can be used for milliOhms measurement?
We are trying to design real four-wire measurement tips, but the user experience is not as good as the normal tips.

Thanks for the quick reply!

WRT your question, I don't have many cases, actually.
This was a question in case other people may have been looking for this functionality as well and/or it was something relatively straightforward to implement.
Looks like it's neither of those, so not a problem for me if it doesn't happen.

[SilverSolder]

A low-ohm measurement could maybe use a higher current? - so the algorithm starts with the low default current, and then tries e.g. a 10x higher current for a short time to make a low ohms reading, if it determines that it is dealing with a low resistance?

[Shannon]

In-circuit testing is always going to have potential pitfalls.  Trying to accomodate various possiblities might create more confusion.

It sounds like what we expect from an instrument is to be simple and correct, and incorrect results can cause more trouble.

[Shannon]

A low-ohm measurement could maybe use a higher current? - so the algorithm starts with the low default current, and then tries e.g. a 10x higher current for a short time to make a low ohms reading, if it determines that it is dealing with a low resistance?

Yes. we can use higher current for low-ohm testing, but it's hard to implement in practice.
For example, there will be a resistor serial in the output driver and DUT, otherwise the output driver is easy to be unstable.
And this serial resistor is much larger than mili-ohm, so the driver current cannot be too large.

Most of the time, we are willing to using ultra-low noise amplifier to get lower test range.
And the other way is to using true four wire measurement.
These two directions are what we are working towards.

[SilverSolder]

A low-ohm measurement could maybe use a higher current? - so the algorithm starts with the low default current, and then tries e.g. a 10x higher current for a short time to make a low ohms reading, if it determines that it is dealing with a low resistance?

Yes. we can use higher current for low-ohm testing, but it's hard to implement in practice.
For example, there will be a resistor serial in the output driver and DUT, otherwise the output driver is easy to be unstable.
And this serial resistor is much larger than mili-ohm, so the driver current cannot be too large.

Most of the time, we are willing to using ultra-low noise amplifier to get lower test range.
And the other way is to using true four wire measurement.
These two directions are what we are working towards.

I guess it may be difficult to design a low/high switchable current output stage that maintains accuracy (doesn't interfere with the low current measurements)?

[indman]

Del

[indman]

Del

[eliocor]

I think you should read:

WITHIN the specified margin of error

[indman]

Del

[ebastler]

Show me this line in the specification document I showed above in the photo?

Why are you now sharing the flyer of a competing device, the Advance Devices smart tweezers?

[indman]

Del

[eliocor]

@indman:
and....?

[ebastler]

ebastler,because I see that the measuring range of both devices is amazingly the same, don't you think?
And what's so secret about this ST5C flyer? It can't be shown here?

No, there is no secret. But you are causing confusion by showing it, when you proclaim to show test results for the Shannon tweezers.

Speaking if which -- do you have any actual test results, maybe even  performance problems? Or are your posts above all you wanted to share?

[indman]

Del

[eliocor]

I just find you behavior rather bizarre....

Do not feed the troll....

[indman]

Del

[ebastler]

So far all I have read from you is nitpicking: There is a rough edge on the plastic; there is a black line missing on the product flyer; one can actually measure over a wider range than the guaranteed range. It's not that I "don't like" your findings -- it's just that I couldn't care less.

[eliocor]

What samples (precision, stability, traceability, ...) are you using to test the tweezers?
With what other device are you making the comparisons?
My tests/comparisons were made using a DER EE DE-5000, 2x Racal Dana 9343M and a TF2700 Bridge and I'm rather happy of my ST-42, especially for the technical discussion I had (outside this forum) with Shannon and his responsiveness (on this forum) in correcting the problems found in the firmware.

[indman]

Del

[KungFuJosh]

Personally, I've only had my Shannon ST-42 tweezers for a little over a year now.  In that time, I've found them to be accurate and reliable. I reported a number of bugs, and Shannon corrected everything with new firmware (I was an early adopter). As others have also done. It's a solid product, with excellent support, at a price point significantly lower than the competitors. I don't understand the need to troll in here at all.

[ono]

I have ET432 LCR meter and I used to have Mastech MS8911 LCR tweezers that I have sold, and I did not observe any significant deviations measuring wide range of L C R components, except that the tip and measurement path resistance may wary slightly depending how you grab DUT. Given the price point, direct contact to the lead engineer, SW updates, I don't think there's any better (bang for the buck) device on the market. I am not sure if there's anything even close to ST in the similar price and form factor.

[battlecoder]

Been following this project for a while and I love how well designed this is.
I finally ordered one, can't wait to have it here and test it!

[tautech]

Shannon convinced me to get a set.....

It arrived sporting v1.4.4 FW that needs upgrading to v1.5.3 before I do some checks against my now aged ST3 and fully report my impressions.

Could any of you fine owners help guide this non-programmer distributor with the CMD syntax as it's very difficult to see in the FW update video. 

Using W10 and have downloaded the update and can get the tweezers into FW install mode which after a while times out and returns to default measure mode.
I see the bit about needing to be in Device manager to set the install path and I'll play with this more to find the port. Also tried to mimic the video by placing the install exe onto the Desktop.

Please can I have some little guidance ?

[dibro]

@tautech try it this way...
extract the latest fw-update to a folder.
connect the Tweezers in Firmware update mode
open a command box in that folder.
type devmgmt.msc ro start the devices manager
In de device manager open the Ports (COM & LPT) section
There should be a USB-SERIAL CH340(COMx) line (where COMx is something like COM3 or COM6)
Now in the command box use: fw_update-win.exe COMx   to start the firmware update (substitute COMx with the correct COM port)

Hope this helps

[KungFuJosh]

Please can I have some little guidance ?

Device Manager:


Find your port as mentioned above, then go to your firmware update folder and run the command with the com port info.

It might look slightly different whether you use powershell or command prompt, but it works either way.

Command Prompt:


Power Shell:



If that's not big enough for ya, I can zoom the text in more. 😉😉