Linux Setup / Driver?

[track02]

Hi,

I'm looking at communicating to an XSR6002S balance via Linux machine, however calling dev = MettlerToledoDevice() gives an error RuntimeError: Could not find any MettlerToledo devices. Check connections and permissions.

But looking under /dev/ I can't see any ttyUSB0 devices, only hidraw0

I've enabled MT-SICS under balance settings and assigned it to USB I've also tried both the USB-A / USB-B port but no apparent difference

Is there an extra driver or something I need to install for the balance to be detected?

Any assistance would be greatly appreciated

[peterpolidoro]

Hi!

This Python library, mettler_toledo_device, uses a serial interface to communicate with Mettler Toledo devices using the MT-SICS commands. I wrote this library years ago, so Mettler Toledo devices may work differently now than they did in the past. Quickly looking at the manual, it appears that this balance does not have an RS232 interface like the older balances did, only USB or Ethernet.

You can look at the Mettler Toledo drivers page to see if they provide a USB driver. The one I see on that page only looks like it works with Windows, unfortunately, but perhaps that would allow you to send serial commands over a USB port. If it does, then this library might just work as-is on a Windows machine with that driver installed.

If you want something that works with Mac or Gnu/Linux, you may need to use some sort of USB serial converter cable. I am not sure how to get those to work when there are USB connectors on both the device and the computer. Most of the converters that I have seen have a USB connector on one side and a DB9 connector on the other. Some have DB9 male pins and some have DB9 female sockets, so MAYBE you could get it to work with two complementary converters, but I have never tried that.

You may also be able to get the USB interface to work directly, but that would require some code changes. There is a PyUSB library for talking to USB devices directly.

You may also be able to get it to work over Ethernet, either by using the MT-SICS commands or the SOAP web interface, but that might require more significant code changes.

I do not have time right now to modify the code, but I am happy to accept pull requests. If you can get it to work, please let me know and I will update the documentation.

[rpzatkoff]

I still use this project for interfacing with MT RS232 scales today, I also leveraged pyusb-scale to learn how to do the same with a very basic USB bench scale using the pyusb library. The project I linked does appear to be dead, but the code is out there for how it works.

[peterpolidoro]

@rpzatkoff thanks!

[track02]

Thank you for the replies

Playing around with it a bit more today, and it does seem like a driver is needed I've tried it with Windows and Mac machines and they don't detect it automatically either which is a shame

Interestingly the balance does automatically detect a female USB-RS232 converter and asks you to configure it as a USB-RS232 device, however connecting that converter to a PC via complementary male USB-RS232 doesn't seem to work as nothing is detected at the PC side so I wonder if a different cable setup is needed

Typically we've used an async variant of PySerial for comms with instruments, pyusb looks to be a bit more low level which may very well be what's needed here, will give it a look too

Serial via Ethernet may be an option however not too practical as it requires wiring the balance back into the network , I'll give it a try if there's no solution over USB/RS232

I've also contacted Mettler so they may have the magic answer I'm missing

I'll let you know of any findings

[namotco]

Curious if there was ever a solution for this. I would even be willing to sponsor the development of a solution...

[peterpolidoro]

Hi,

What exact solution do you need? Which specific scale do you want to communicate with?

[namotco]

We have been working with a MT XSR204/a on a linux device. It has a number of USB ports, the linux side sees the Mettler Toledo device, but no TTY: ***@***.***:~$ cat /dev/tty tty tty10 tty13 tty16 tty19 tty21 tty24 tty27 tty3 tty32 tty35 tty38 tty40 tty43 tty46 tty49 tty51 tty54 tty57 tty6 tty62 tty8 ttyBT1 ttyS1 tty0 tty11 tty14 tty17 tty2 tty22 tty25 tty28 tty30 tty33 tty36 tty39 tty41 tty44 tty47 tty5 tty52 tty55 tty58 tty60 tty63 tty9 ttyp0 ttyS5 tty1 tty12 tty15 tty18 tty20 tty23 tty26 tty29 tty31 tty34 tty37 tty4 tty42 tty45 tty48 tty50 tty53 tty56 tty59 tty61 tty7 ttyBT0 ttyS0 ***@***.***:~$ lsusb Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 006: ID 0eb8:2102 Mettler Toledo Bus 004 Device 005: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub [image: image.png] We have been trying to connect to this balance a number of different ways, but we either get no TTYUSB/COM/etc OR no data from it. We also tried using a USB -> RS-232 -> another RS-232 -> USB cable to "trick" the balance into seeing a printer device, but that also yielded no data.

…

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[peterpolidoro]

I quickly skimmed the datasheet. It says the RS-232 interface is optional? Did you order it with that option? Unfortunately I do not have one of those scales to test.