Tenma 72-7730 in Linux

I bought a Tenma 72-7730 DMM for work so we could record data from our temperature chamber. The DMM is reasonably priced for a USB based instrument. Unfortunately it did not come with a driver or software for linux, only windows, so I was stuck reverse engineering the interface. The USB is based on a Hoitek UART to USB device that interfaces into the linux HID code instead of the serial tty driver. The Hoitek site is currently down (looks like they lost their domain name, maybe they were bought or something) but I found enough documentation on the internet to set the bit rate for the device so I could see what was coming on the HID interface. Long story short, here is the resultant gnu/linux software to fetch raw data, screen readings, and floating point values from the DMM. The software can be run stand-alone or as a library for  your own application. Instructions are included.

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11 Responses to “Tenma 72-7730 in Linux”

  1. Tenma 72-7730 in Linux « Relavak Labs Software Rss Says:

    […] here to see the original:  Tenma 72-7730 in Linux « Relavak Labs By admin | category: Object | tags: code-instead, did-not, fedora, firewalls, hoitek, […]

  2. thorsten Says:

    works fine.
    probably never gonna use it but youll never know….

  3. John Pitney Says:

    Works fine for me on a Fedora 12 box after changing to /dev/hidraw2.

    Thanks!

  4. M.Krage Says:

    It worked fine, but I only get “TenmaCreate: Connection timed out” on newer Linux distros like Ubuntu 12.04.

  5. Kees Schoenmakers Says:

    I tried it (on Linux-3.5.0) and got no success :-(. I made a udev rule which resulted in a “/dev/tenma” though.

    drwxr-xr-x 2 root root 3960 Aug 1 14:14 char
    crw-rw-rw- 1 root root 249, 3 Aug 1 14:14 tenma
    crw——- 1 root root 249, 3 Aug 1 14:14 hidraw3
    drwxr-xr-x 2 root root 60 Aug 1 14:14 usb

    ATTRS{idVendor}==”04fa”, ATTRS{idProduct}==”2490″, MODE=”0666″, GROUP=”hidraw”, NAME=”tenma”

    That makes the device easier to define. I tried with /dev/hidraw3 too but sadly no result either. I keep getting “TenmaCreate: Connection timed out” all the time.

    Kees

  6. r4yburn Says:

    Hi I get “TenmaCreate: Connection timed out” all the time also, I have changed hidraw … can anyone help please?

  7. Kees Schoenmakers Says:

    Don’t Forget!!! Important: PUT METER IN SEND MODE FIRST!!!!!
    I had the same timeout message, tried it from Win-XP via VMplayer and had also read-out problems. Only here the message was more informative. So it works excellently…..

  8. Bill Cooper Says:

    If you place an IR receiver against the transmitter you’ll find it’s a very simple rs232 comms format, 2400,7,1,none and no handshake (of course) you get back a string of 11 bytes first 5 are the reading 6th = decimal point position, with the rest being for range etc. feed this data into any terminal program to decode the last bytes – why even try to reverse engineer the USB? all sorted in a few hours. For my IR device I merely placed the anode to pin 4 of a 9 pin female and the cathode to pin 2 ( i found a regular + 6volts on pin 4!

    Happy days!

  9. tonyleg Says:

    Hi,
    I know this thread is old, but I hope to get an answer. I have a slightly different model, 72-7730A, that I try to connect to Ubuntu. When i run the program it tells: “TenmaCreate: Protocol error”.

    would you know how to fix it?

    Thanks.

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