Item Quality of integrated BACnet server items

Owned by Wolfgang Granzer
Last updated: Nov 07, 2023 by Stefanie Furtak

Each server item within our NETx Server has a quality. This item quality reflects the quality of the item's value i.e. whether the current value of the item can be trusted or not. If the quality is "GOOD", the values are shown as green within the Server Item Tree – if they are not good ("UNCERTAIN" or "BAD") they are shown as red and the value is replaced by ???.

If a BACnet items is shown as "not good", there can be different reasons for that.

BACnet device is offline

If the BACnet device is offline, all corresponding BACnet objects i.e. server items are shown as UNCERTAIN. In that case, the corresponding GATEWAY item shows False:

The reason can be that the device is not reachable via network or that the BACnet device status of the device is not "operational". The device status can be verified by clicking on the device within the Item Tree and search for the Item Property "system-status".

The device status is specified by the BACnet standard.

  • operational
  • operational-read-only
  • download-required
  • download-in-progress
  • non-operational
  • backup-in-progress

"non-operational" normally indicates that the BACnet is not reachable via the network. For more details take a look at the BACnet specification and at the datasheet / user manual of your BACnet device.

BACnet device is online but some items are shown as UNCERTAIN

If a BACnet device is online but one or more items are shown as UNCERTAIN, the so called status flags of the BACnet object may report a failure. Each BACnet object has a property "status-flag" which provides information about the quality of the object's value. This property is a bit field that has the following subfield:

  • in-alarm
  • fault
  • overridden
  • out-of-service

In addition the property "Reliability" provides additional information in case a fault occurs. 

These status flags are also shown as item properties within our NETx Server. To show them, select the BACnet object in the server item tree and take a look at the item's properties:

In some use cases, it is desired to show item value as GOOD even if one of these flags is true. To configure this behavior, open BACnet > Driver Configuration ... and enable the corresponding options. For example, to show the item value as GOOD if the status flag "FAULT" is true, enable the following option: