Author Topic: Yet another Tonghui TH2822A LCR meter review in pictures  (Read 27092 times)

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Offline reagle

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Yet another Tonghui TH2822A LCR meter review in pictures
« on: April 07, 2013, 07:16:52 pm »
Just posted a boatload of pictures of the Tonghui Th2822A LCR meter I bought after almost a year of contemplating which brand/model to go with.
http://kuzyatech.com/tonghui-th2822a-lcr-meter
Seems very nice for the amount paid ($175 +$35 shipping), though I do question the -2mF reading at one of the test frequencies :)
On a positive note, I see no signs of the min/max/avg bug Dave found in the BK879B unit


« Last Edit: April 07, 2013, 08:20:35 pm by reagle »
 

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #1 on: April 11, 2013, 02:40:31 am »
    Interesting enough, I have a TH2822 (100 Hz - 1 Khz version) that has the problem with the MIN/MAX/AVG, exactly as Dave found on the BK Precision 879B... And this makes me think that both units share the same firmware... Because the hardware is obviously identical, except the input protection board that the BK doesn't have.

   
Valentin
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #2 on: April 11, 2013, 12:21:15 pm »
What firmware version does yours report?
On boot, mine flashes:

2.1.1.1
2822A

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #3 on: April 11, 2013, 08:51:16 pm »
     I'm away for a few days... I will reply when I get back and verify what version mine has.
Valentin
 

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #4 on: April 14, 2013, 07:17:35 pm »
2.0.10    (without a dot between 1 and 0)
2822

replies mine ...  yours has a newer firmware, but on the Tonghui website there isn't any firmware update file :(
« Last Edit: April 14, 2013, 07:22:22 pm by valentinc »
Valentin
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #5 on: April 14, 2013, 07:20:27 pm »
No dot here either. I had to take a picture to capture it again- it flies by too fast:)
 Mine says
2.1.11
2822A

Now we need to find somebody with a  BK  meter to compare

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #6 on: April 14, 2013, 07:26:15 pm »
Yes. I bet that the firmware is the same...

Read this about Siglent and LeCroy... it's the same thing

https://www.eevblog.com/forum/testgear/siglent-sdg1000-(aka-lecroy-wavestation)-firmware-updates/
Valentin
 

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #7 on: April 14, 2013, 07:32:49 pm »
If you can, please post a high res photo of the board of your Tonghui... I want to compare to see if the max frequency is determined by a couple of 0 ohm resistors... it could be
Valentin
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #8 on: April 14, 2013, 07:46:49 pm »
Any particular corner of it? It's a bit tough to get everything equally sharp

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #9 on: April 14, 2013, 07:54:02 pm »
Most probably, if there are any resistors to do that are at the top, near the CPLD and MSP430 microcontroller ... But it's better if you take 2 or even 3 pictures to compare the entire board (except the input board that has obviously nothing to do with this)

I will be very happy to hack this LCR meter, since the 100 Khz version is very expensive...
« Last Edit: April 14, 2013, 07:57:31 pm by valentinc »
Valentin
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #10 on: April 14, 2013, 08:22:19 pm »
Assuming the firmware is the same in all, I'd like to try that too. I need to get some low measurement ranges that even 10Khz is not reaching.
Here are the pictures- let me know if you need more details

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #11 on: April 14, 2013, 10:17:30 pm »
  At a first look the boards look identical (my TH2822 and your TH2822A). The only difference is on the TH2822C, which has additional circuitry for charging the 9V Ni-Mh battery, which ours don't have... I'll investigate further and let you know what I'll find.

  Now the problem is I can't find the firmware update for the BK Precision 879B on their website...

  If you can find the firmware update file for the BK, please let me know...
« Last Edit: April 14, 2013, 10:19:51 pm by valentinc »
Valentin
 

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #12 on: April 15, 2013, 02:43:25 pm »
Now I see, even the silkscreen with the board name is the same: TH2822-MAIN
                                                                                                        VER 1.1@2010-10

It's clear that the differences between the models are in the EEPROM next to the microcontroller or in the flash of the microcontroller. I'll try to probe with my oscilloscope to see if I can figure out what's in that memory... My guess is the calibration data and some ID's for different models...
« Last Edit: April 15, 2013, 02:46:45 pm by valentinc »
Valentin
 

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #13 on: April 16, 2013, 10:51:16 am »
    It seems that only at startup (boot) there is a data transfer between the EEPROM and the microcontroller, in rest, anything you do there isn't any data transfer. I couldn't capture the entire data on my scope (because it hasn't enough memory), but it's clear that at boot time the uC receives some ID of the model number and eventually some calibration data...

    I don't have an EEPROM programmer, that would be the next step, to unsolder the chip and read its contents. And maybe it can be modified and written on another chip (because it has write protect).

    And I also wonder if it can be done via SCPI commands (like the Rigol DS1052E) ...
Valentin
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #14 on: April 16, 2013, 12:26:46 pm »
Let me see if I can sniff I2C traffic on the EEPROM. Between Bus Pirate and Saelae Logic 16, i should be able to figure it out :)

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #15 on: April 16, 2013, 03:29:38 pm »
If the data in the EEPROM is not encrypted we should be able to figure it out :)
Valentin
 

Offline ivan747

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #16 on: April 16, 2013, 08:58:19 pm »
I honestly doubt the data is encrypted. Not even Agilent encrypt their model data.
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #17 on: April 16, 2013, 09:01:04 pm »
At the moment I am setting up Saelae  Logic to grab I2C traffic. If I don't feel too lazy, I may try reading the eeprom out with bus pirate, but that requires actually actively using my brain ;)

Offline ivan747

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #18 on: April 16, 2013, 09:04:22 pm »
Can't you setup the Bus Pirate to read the whole chip into an hex file?
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #19 on: April 16, 2013, 09:12:20 pm »
That's what I meant by having to actually use my brain :)
For now here is a grab of the i2C traffic on boot

Offline ivan747

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #20 on: April 16, 2013, 09:33:46 pm »
That's what I meant by having to actually use my brain :)
For now here is a grab of the i2C traffic on boot

Change the extension to CSV to open it in a spreadsheet.  :-+
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #21 on: April 16, 2013, 09:39:31 pm »
If read as ASCI, it reads out the firmware rev first VER2.1.1103. rest is less obvious ;)

Offline valentinc

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #22 on: April 16, 2013, 09:44:39 pm »
Can you post the data in ASCII format ?
Valentin
 

Offline reagle

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #23 on: April 16, 2013, 09:50:45 pm »
Try this one

Offline ivan747

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Re: Yet another Tonghui TH2822A LCR meter review in pictures
« Reply #24 on: April 16, 2013, 10:01:56 pm »
I converted it into CSV, and added some comments. I already found some sort of pattern.

Look by yourself. Change the extension to .csv
 


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