Goal

To Develop only the Firmware for M181 LCR Meter made by JyeTech. Hope to provide understanding in basics of LCR Meter.

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Note

• This firmware is still under development.
• For a fully reworked version, please refer to the firmware at OneOfEleven/M181-LCR-Meter-Firmware.

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Current Status

• Reverse Engineer the schematics and document notes
• Prepare a LTspice simulation. <<< Reworking.
• Basic driver layer prepare used STM32Cube.
• Solve by noise problem in ADC captured data >>> (**Temp) Average
• Add Low Filter and DC block <<< Working here.
• Calculate amplitude and phase difference of Volt, Current.
• LCR forumla implementation with Mode option
• Save the settings option in MCU memory
• Calibration mechanism

Hardware - M181 LCR Meter

• Official product page link here
• I have purchased from Banggood, buying link is here

System Overview

MCU programming

• Programmer → Raspberry pi debug probe (**modified)
• Interface → SWD
• IDE → PlatformIO
• Framework → STM32Cube

Programming setup image

Output parameter

• Ser → Calculation mode Series or Parallel
• 1.0kHz → Frequency signal used for measurement
• V0.20 → Firmware Version
• C → Capacitance **Mode Change
• V → RMS Voltage across the DUT
• A → RMS Current flowing via DUT
• ER → Equivalent Series Resistor(ESR)
• D → Dissipation factor (or) Tan Delta

Analysis Original JYETech Firmware

1. With 10nF Film as a load

Connected 10nF Capacitor as a load then capture waveform and UART serial output

Note:

2. VI/GS Pin handling (open load condition)

VI and GS Pin is not HIGH simultaneously during Open Circuit

3. VI/GS Pin handling (Short Circuit condition)

VI - HIGH, GS - LOW not happening during short circuit

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Detailed Wiki Page

Further details will be added in Wiki page