Online State

Associated with: Sparkplug™ Edge Nodes and Sparkplug Devices

Use this Online State status attribute in conjunction with the Online State Alarm attribute to ascertain the connection status of the selected Sparkplug Edge Node or Device.

With a Sparkplug Edge Node, the possible values of the Online State status attribute are:

• False, no NBIRTH received—This value indicates that one of the following applies:

  • The driver has never attempted to use the Edge Node database item for communications with a broker. This applies, for example, to an Edge Node item that has been added to the Geo SCADA Expert database, but has not yet been placed In Service.
  • Geo SCADA Expert has attempted to communicate with the Edge Node that the Edge Node database item represents, but the node has not sent a NBIRTH message.

  Once the driver communicates successfully with the node to which the Edge Node database item represents, the Online State status attribute updates to display one of the values shown below.

• True, NBIRTH received <date and time>—This value indicates that the node is online and capable of communicating with the broker. The driver received the Sparkplug birth certificate for the node at the time and date shown. The NBIRTH indicates that the node is online and so capable of transmitting and accepting data.

• False, NDEATH received <date and time>—This value indicates that the driver received the Sparkplug death certificate from the node at the time and date shown. This indicates that the node has gone offline. As such, Geo SCADA Expert is no longer able to communicate with that node.

  If the node has gone offline unexpectedly, use other status attributes, such as the Edge Node's Quality status attribute, along with the Events List and Alarms List, to help determine the reason for that change in status. Also check the Connection State of the Sparkplug Broker.

  If an Edge Node goes offline, the Online State of any devices that are associated with that node will initially remain unchanged. The Online State of those devices will continue to indicate a value of 'True' until the driver has received the Sparkplug death certificates from those devices. However, the devices will display a 'Comm Failure' Quality to indicate that the Edge Node with which they are associated is not responding and therefore deemed to have gone offline.

With a Sparkplug Device, the possible values of the Online State status attribute are:

• False, no DBIRTH received—This value indicates that one of the following applies:

  • The driver has never attempted to use the Device database item for communications with a broker. This applies, for example, to a Device item that has been added to the Geo SCADA Expert database, but has not yet been placed In Service.
  • Geo SCADA Expert has attempted to communicate with the device that the Device database item represents, but the device has not sent a DBIRTH message.

  Once the driver communicates successfully with the physical or logical device or sensor to which the Device database item relates, the Online State status attribute updates to display one of the values shown below.

• True, DBIRTH received <date and time>—This value indicates that the device is online and capable of communicating with the broker. The driver received the Sparkplug birth certificate for the device at the time and date shown. The DBIRTH indicates that the device is online and so capable of transmitting and accepting data.

• False, DDEATH received <date and time>—This value indicates that the driver received the Sparkplug death certificate from the device at the time and date shown. This indicates that the device has gone offline. As such, Geo SCADA Expert is no longer able to communicate with that device.

  If the device has gone offline unexpectedly, use other status attributes, such as the Device's Quality status attribute, along with the Events List and Alarms List, to help determine the reason for that change in status. Also check the Online State status attribute of the Sparkplug Edge Node with which the Device is associated.

  If the Edge Node goes offline, the Online State of any devices that are associated with that node will initially remain unchanged. The Online State of those devices will continue to indicate a value of 'True' until the driver has received the Sparkplug death certificates from those devices. However, the devices will display a 'Comm Failure' Quality to indicate that the Edge Node with which they are associated is not responding and therefore deemed to have gone offline.

Also see Online State Alarm.