Products > Test Equipment
Shannon ST42 LCR Tweezer Test and Comparison Thread
KungFuJosh:
It's definitely past your bedtime!
Martin72:
--- Quote from: Martin72 on July 02, 2024, 11:14:03 pm ---I have downloaded it and I have questions about it.... ;)
--- End quote ---
More than this thread can cover...
Maybe we should discuss the rest somewhere else, maybe in the ST2830 thread.
But three things after all:
-Why did you enter the output voltages for the ST2832 and ST42 differently, in Vrms for the ST2832 and in Vpp for the ST42?
-Why did you not use frequencies below 1kHz for the inductances, at least for the larger coil values it would have been permissible.
-And the third, measuring coils in the higher mH range at 100khz or more, hardly makes any practical sense.
But it's nice to see that the ST42 can still keep up with the capacitors, I've noticed that too.
KungFuJosh:
--- Quote from: Martin72 on July 03, 2024, 09:38:07 pm ---More than this thread can cover...
Maybe we should discuss the rest somewhere else, maybe in the ST2830 thread.
But three things after all:
-Why did you enter the output voltages for the ST2832 and ST42 differently, in Vrms for the ST2832 and in Vpp for the ST42?
--- End quote ---
Because that's how each device is specified. 1V on the ST42 is 1Vpp, and on the ST2832 it's 1Vrms.
--- Quote from: Martin72 on July 03, 2024, 09:38:07 pm ----Why did you not use frequencies below 1kHz for the inductances, at least for the larger coil values it would have been permissible.
--- End quote ---
My tests followed the calibration chart that came with your ST2830. Your cal only showed testing inductance at 1kHz, so I added the others for fun. I did expand on a few areas to see what the devices could handle, but my tests covered at least what the original cal cert did, except that I changed values to simple 1, 10, 100 for each range (in resistance) rather than the other seemingly arbitrary intermediate values. If you want me to cover something else specifically, let me know and I'll add it before I do my 5th (and hopefully final) version of the test board.
--- Quote from: Martin72 on July 03, 2024, 09:38:07 pm ----And the third, measuring coils in the higher mH range at 100khz or more, hardly makes any practical sense.
--- End quote ---
Practical sense or not, that falls in the 1% accuracy range at worst according to their chart. Why not push a little and see how well it works?
--- Quote from: Martin72 on July 03, 2024, 09:38:07 pm ---But it's nice to see that the ST42 can still keep up with the capacitors, I've noticed that too.
--- End quote ---
Indeed, the ST42 did quite well across the board. I was surprised by the few failures testing at 10kHz, but I don't know what the ST42 is supposed to handle. Hopefully Shannon can release some more detailed specifications.
I'm happy to discuss this further wherever you like. 😉
Martin72:
Hi,
--- Quote ---Because that's how each device is specified. 1V on the ST42 is 1Vpp, and on the ST2832 it's 1Vrms.
--- End quote ---
This can be converted accordingly, one into the other or vice versa.
Two different units make it difficult to compare them at first glance.
--- Quote ---My tests followed the calibration chart that came with your ST2830. Your cal only showed testing inductance at 1kHz
--- End quote ---
Oh, is that so?
Then I'll have to have another serious word with the calibration laboratory.
--- Quote ---Practical sense or not, that falls in the 1% accuracy range at worst according to their chart. Why not push a little and see how well it works?
--- End quote ---
This was not meant in the context of the accuracy of the LCR.
--- Quote ---I was surprised by the few failures testing at 10kHz, but I don't know what the ST42 is supposed to handle.
--- End quote ---
In this regard, I would exhaust the calibration possibilities of the ST42 before the measurements, if you have not already done so.
Unfortunately, this is unavoidable as soon as you change the measuring frequency, even with the ST2830, if you want to know exactly.
--- Quote ---If you want me to cover something else specifically, let me know and I'll add it before I do my 5th (and hopefully final) version of the test board.
--- End quote ---
I think the idea of a test board is very good, I had already thought about it a few times, because the LC option of the DMM Check Plus is a bit too meager for me, apart from the fact that normal components were installed there, which were only measured.
In this respect:
--- Quote ---I'm happy to discuss this further wherever you like.
--- End quote ---
If you (or I) would start a dedicated thread via a testboard.
KungFuJosh:
--- Quote from: Martin72 on July 03, 2024, 11:17:13 pm ---I think the idea of a test board is very good, I had already thought about it a few times, because the LC option of the DMM Check Plus is a bit too meager for me, apart from the fact that normal components were installed there, which were only measured.
In this respect:
--- Quote ---I'm happy to discuss this further wherever you like.
--- End quote ---
If you (or I) would start a dedicated thread via a testboard.
--- End quote ---
Hmmm, I definitely should have corrected the voltages. I was too tired when I did that now that I think of it, and both voltages are shown in Vrms. Though the ST42 shows voltages in Vpp on it's display. Since the purpose is to see if the devices are in spec, they should be measured and displayed in the correct method for each device. I should have corrected that. I will. Thanks for pointing that out.
I don't want to exhaust the cal abilities of the ST42 on my own. I would like Shannon to specify what it should be capable of at each frequency, and use the test to confirm that. I can't know if it's out of spec without specs.
I would definitely like to discuss the board more before I make another version. It's pretty close, but I need some advice I think on a couple things.
Thanks,
Josh
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