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Carel pCOweb Devices

The pCOWeb card is used to interface the pCO system to networks that use the HVAC protocols based on the Ethernet physical standard such as SNMP. The problem with this card is that the implementation is based on the final manufacturer of the HVAC (Heating, Ventilation and Air Conditioning) and not based on a standard given by Carel. So each pCOweb card has a different configuration that needs a different MIB depending on the manufacturers implementation.

The main problem is that LibreNMS will by default discover this card as pCOweb and not as your real manufacturer like it should. A solution was found to bypass this issue, but it's LibreNMS independent and you need to first configure your pCOWeb through the admin interface.

Accessing the pCOWeb card

Log on to the configuration page of the pCOWeb card. The pCOWeb interface is not always found when accessing the ip directly but rather a subdirectory. If you cant directly reach the configuration page try <ip address>/config. The default username and password is admin/fadmin. Modern browsers require you to enter this 2 or 3 times.

Configuring the pCOweb card SNMP for LibreNMS

First you need to configure your SNMP card using the admin interface. An SNMP tab in the configuration menu leaves you the choice to choose a System OID and a Enterprise OID. This is a little tricky but based on this information we defined a "standard" for all implementation of Carel products with LibreNMS.

pCOweb

The base Carel OID is 1.3.6.1.4.1.9839. To this OID we will add the final manufacturer Enterprise OID. You can find all enterprise OID following this link. This will allow us to create a specific support for this device. Librenms uses this value to detect which HVAC device is connected to the pCOWeb card.

Example for the Rittal IT Chiller that uses a pCOweb card:

  1. Base Carel OID : 1.3.6.1.4.1.9839
  2. Rittal (the manufacturer) base enterprise OID : 2606
  3. Adding value to identify this device in LibreNMS : 1
  4. Complete System OID for a Rittal Chiller using a Carel pCOweb card: 1.3.6.1.4.1.9839.2606.1
  5. Use 9839 as Enterprise OID

The way this works is that the pCOWeb card pretends to be another device. In reality the pCOWeb card just inserts the "enterprise OID" in place of the vendor id in the OID.

In the table below you can find the values needed for devices which are already supported.

Supported devices

LibreNMS is ready for the devices listed in this table. You only need to configure your pCOweb card with the accorded System OID and Enterprise OID:

Manufacturer Description System OID Enterprise OID
Rittal IT Chiller 1.3.6.1.4.1.9839.2606.1 9839
Rittal LCP DX 3311 1.3.6.1.4.1.9839.2606.3311 9839.2606

Unsupported devices

After constructing the correct System OID for your SNMP card, you can start the LibreNMS new OS implementation and use this new OID as sysObjectID for the YAML definition file.

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