[collectd] Modbus support

Matt Baker matt at sevenone.com
Thu Jan 6 01:06:34 CET 2011

Hi Octo,

Thankyou for getting back to me so quickly and your help. I will give the updated code a try later today.

The plan in regards to the modbus plugin was to use Collectd as part of a building management system. At the moment we have some airconditioning and power systems connected by modbus to a serial/ethernet gateway unit. This device [0] already allows us to map modbus registers through to snmp which we monitor using Nagios and graph using pnp4nagios. This works well, but we are limited to the number of registers we can map through to snmp.

Instead I was looking at talking direct modbus/tcp to the gateway with collectd, and then use collectd-nagios to send through to Nagios warnings if values fall out of range.



[0] http://www.barix.com/Barionet_100/511/

> Hi Matt,
> On Wed, Jan 05, 2011 at 09:25:00PM +1030, Matt Baker wrote:
>> Initially I tried against the latest unstable version of libmodbus,
>> 4.9.2 but found that running configure of collectd did not find the
>> modbus libraries unless I used 'force'.
> unfortunately, the author of libmodbus breaks backwards compatibility
> often, especially in the releases after 2.0.3 which are marked
> "experimental". That's why those newer versions will only be supported
> when another "stable" version emerges.
> The current master branch contains some compatibility code with 2.9.2,
> but this will be updated as libmodbus changes. Use 2.0.3 for now to be
> safe.
>> Switching to libmodbus 2.0.3 and the configure run found everything
>> okay, but the compile is resulting in:
> A fixed version of the code is available in the Git repository and will
> be released as 4.10.3 eventually. The commit fixing this is 491712a [0],
> you can download the fixed file from [1].
> Just out of curiosity, can you share what you're using the plugin for?
> Best regards,
> —octo
> [0] <https://github.com/octo/collectd/commit/491712ab7dd36eb58fba23942f5edf4b76b50361>
> [1] <https://github.com/octo/collectd/raw/491712ab7dd36eb58fba23942f5edf4b76b50361/src/modbus.c>
> -- 
> Florian octo Forster
> Hacker in training
> GnuPG: 0x0C705A15
> http://octo.it/

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