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I am currently working with an oscilloscope capable of analyzing a signal using a few protocol's standards (like RS232, SPI, I2C etc...) except for Modbus and RS485. I need it to determine wether a modbus gateway is working correctly or not.

I would like to know if there is a software able to :

  • access my oscilloscope and use the current measurements as its input

OR

  • take an image or dedicated file format as its input

THEN

  • decode the Modbus frame byte by byte

For example, this is what I have in mind when I say decode byte by byte :enter image description here

This is the result when I decode a Modbus frame using RS232 settings.

The only softwares I've found are serial port monitors which are not exactly what I'm looking for.

By the way, I'm using a LeCroy waveRunner 64MXi oscilloscope (soft. ver. 5.9.0.2)

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It looks like sigrok/PulseView supports it: https://sigrok.org/wiki/LeCroy_oscilloscope_series, https://research.kudelskisecurity.com/2020/01/08/decoding-lecroy-oscilloscope-traces-with-sigrok/.

Just a small warning: MODBUS has about a dozen rarely used request types that are probably not supported by anything on the market. Commonly used reading/writing registers/coils would be fine though.

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  • it looks like exactly what I needed thanks. Do you perhaps know any good ressource on pulseview's decoding tool ? Aug 30 at 14:27
  • I don't, when it works it is quite intuitive with its protocol configuration and stacking. Device specific configuration might be not obvious (like installing WinUSB driver for salae clones), but there is a chance auto detection would work.
    – TMSZ
    Aug 30 at 15:02

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