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.

This entry was posted on October 4, 2009 at 2:19 am and is filed under Drivers. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

11 Responses to “Tenma 72-7730 in Linux”

Tenma 72-7730 in Linux « Relavak Labs Software Rss Says:
October 4, 2009 at 5:23 am | Reply
[…] here to see the original: Tenma 72-7730 in Linux « Relavak Labs By admin | category: Object | tags: code-instead, did-not, fedora, firewalls, hoitek, […]
thorsten Says:
October 23, 2009 at 12:06 pm | Reply
works fine.
probably never gonna use it but youll never know….
John Pitney Says:
August 25, 2010 at 12:53 am | Reply
Works fine for me on a Fedora 12 box after changing to /dev/hidraw2.

Thanks!
M.Krage Says:
June 18, 2012 at 6:30 pm | Reply
It worked fine, but I only get “TenmaCreate: Connection timed out” on newer Linux distros like Ubuntu 12.04.
Kees Schoenmakers Says:
August 1, 2012 at 12:26 pm | Reply
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
r4yburn Says:
May 15, 2014 at 7:16 am | Reply
Hi I get “TenmaCreate: Connection timed out” all the time also, I have changed hidraw … can anyone help please?
Kees Schoenmakers Says:
December 17, 2014 at 9:23 am | Reply
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…..
Bill Cooper Says:
February 2, 2015 at 11:34 am | Reply
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!
tonyleg Says:
May 9, 2017 at 10:35 am | Reply
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.