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Tenma 72-7732A Comport / HID

Zacory

Hello,

I'm trying to write a Python Script that reads the output of Tenma 72-7732A Digital Multimeter, while I am aware of the software that comes with it on the installation disk, I want a Python Script.

When plugging in the Optical to USB lead into the machine, it appears as a "HID Vendor Compliant Device" not as a comport. 

I have attempted to read the USB, all I get is B[0,0,0,0,0,0]

I am wondering if anyone has successfully read this device with Python, as a comport or as a HID Device?

Thank you!

Parents

  • HID devices communicate exchanging "reports" which are just blocks of bytes. The Operating system can query their "Report Descriptor" which should tell the kind of device it is, the "endpoints" and the sizes of the reports for input and output. They are not as simple as just sending bytes down the line, unfortunately.

    Now, if you are willing to do the reverse engineering of the protocol yourself, there's a library for Python called pyhidapi that would allow you to connect to the device and read and write these reports. Now, you will probably also need a tool that allows you to dump the report descriptor from the device, to see the structure of the reports (which will depend on what operating system you are running), or better yet, you can set up a USB monitoring tool to capture the reports sent back and forth between the device and the official software to get an idea of what is being sent or received.

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  • HID devices communicate exchanging "reports" which are just blocks of bytes. The Operating system can query their "Report Descriptor" which should tell the kind of device it is, the "endpoints" and the sizes of the reports for input and output. They are not as simple as just sending bytes down the line, unfortunately.

    Now, if you are willing to do the reverse engineering of the protocol yourself, there's a library for Python called pyhidapi that would allow you to connect to the device and read and write these reports. Now, you will probably also need a tool that allows you to dump the report descriptor from the device, to see the structure of the reports (which will depend on what operating system you are running), or better yet, you can set up a USB monitoring tool to capture the reports sent back and forth between the device and the official software to get an idea of what is being sent or received.

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