Modbus driver

[aquette]

Create a generic driver to support Modbus devices.

It will:

• use libmodbus (http://libmodbus.org)
• support both RTU (RS232/485) and TCP communication
• support various devices (ups, meters, ...)
• use external definition files, including default communication settings (for RTU), and data mapping

A preliminary support has already been committed:
https://github.com/networkupstools/nut/tree/nutdrv-modbus

[clepple]

Just noticed that the other two drivers which start with "nutdrv" use an underscore ("nutdrv_qx" and "nutdrv_atcl_usb".

[aquette]

Fixed, thx for pointing. I've not renamed the branch though, just src / doc occurrences

[sivann]

Hello, do you have a roadmap for modbus support? I'm interested for an industrial UPS support (phoenixcontact) which uses modbus. If not I will implement something. A generic modbus driver does not seem something realistic though.

[aquette]

thanks to @sivann work, there is a modbus RTU (serial) driver that can serve to create a 1rst mapping and actual testing. See #404
The already reference #139 for APC can serve too...

[edalquist]

Yes they have RJ45 form factor serial ports

[jimklimov]

Note: this request got lost on the bookshelf over time, so while several modbus-capable drivers were added to NUT in the past couple of years, and some more are in progress, they are not subdrivers under a common executable/CLI/config-option umbrella, but standalone consumers of libmodbus. For full list see sources and the label reference below; driver efforts that stand out include:

• adelsystem-cbi
• huawei-ups2000
• socomec-jbus
• generic-modbus
• phoenixcontact-modbus
• INVT UPS

Another note: while there are technically an ASCII and a binary modbus protocol flavours, ascii support in libmodbus is only on a side branch and apparently was not good enough to merge to mainstream. So drivers should avoid it (e.g. PR #modb tried to import a copy to NUT codebase, which was not a good place to maintain it long-term).

• modbus (open issues and PRs)
• https://github.com/networkupstools/nut/issues?q=label%3Amodbus+is%3Aclosed (closed or merged PRs and issues)

[WiredWonder]

Thanks @jimklimov

For a Debian sysadmin who just wants better data from his recent USB APC UPS, what's the best option right now?

Jason

[jimklimov]

Can't really say as I have not had APCs for a while. It seems that setting up apcupsd (possibly from source - Debian packages were made in a way that they conflict on helper symlink names) is reasonable, either standalone or along with NUT apcupsd-ups driver to "retranslate" that device's data (and mgmt?..) to NUT ecosystem if desired.

Overall the "APC+ModBus" theme (or in other words, better support for APCs released after ~2010) is tracked (not much progress yet though) in #139

[shom]

libmodbus-3.1.9 not work. 3.1.8 it's work.