State

Associated with: OPC UA Servers and OPC UA Subscription items

The State status attribute is common to many types of database item (see State in the Geo SCADA Expert Guide to Drivers). This topic provides information about the values that are supported by that status attribute on OPC UA Servers and OPC UA Subscription items (which differ slightly to those supported by other database items).

An OPC UA Server might be in one of these states:

• Disconnected—Geo SCADA Expert is not connected to the OPC UA server. This might be for any of a number of reasons, such as:
  • The OPC UA server’s configuration is incomplete—for example, the Server URL has not been specified (see Checking for Invalid Configuration).
  • The OPC UA server is not In Service (in which case, the server will typically display an ‘Out of Service’ Quality).
• Starting—This indicates that Geo SCADA Expert is currently establishing a connection to the OPC UA server. This state is typically fleeting, after which it changes to, either the Healthy or Failed state.
• Healthy—Geo SCADA Expert has successfully connected to the OPC UA server.
• Failed—Geo SCADA Expert has not successfully established or maintained a connection to the OPC UA server. To ascertain further information about the reason for this state, use the Display Alarms pick action to display the OPC UA Server’s Alarms List, or the Display Events pick action to display the OPC UA Server's EventsList.
• Stopping—This indicates that Geo SCADA Expert is currently disconnecting from the OPC UA server. This state is typically fleeting, after which it changes to the Disconnected state.

An OPC UA Subscription might be in one of these states:

• Disconnected—The subscription is inactive. This might be for any of a number of reasons, such as:
  • The configuration of the OPC UA Subscription and/or its associated OPC UA Servers are invalid (see Checking for Invalid Configuration).
  • The OPC UA Subscription and/or its associated OPC UA Servers are out of service. (The item that is not In Service will typically display an ‘Out of Service’ Quality.)
• Starting—The subscription is currently being added to one or more of the OPC UA servers. Only once the subscription has been added to all of the servers the subscription will change to one of the Healthy or Failed states.
• Healthy—The subscription is able to communicate successfully with the OPC UA server. This state only appears with a single OPC UA server subscription (as opposed to a multiple OPC UA server configuration).
• Failed—Geo SCADA Expert has either not been successful in connecting to the subscription's server or the subscription was not successfully added to the OPC UA server. To ascertain further information about the reason for this state, look at the state of the OPC UA server to determine if that server is the cause of the problem, or use the Display Alarms pick action to display the group’s Alarms List. This state only appears with a single OPC UA server subscription (as opposed to a multiple OPC UA server configuration).
• All Healthy—The subscription has been added to all of the OPC UA servers. This state only appears with a multiple OPC UA server subscription configuration.
• All Failed—Geo SCADA Expert has either not been successful in connecting to the subscription's server, or the subscription was not successfully added to the OPC UA server. To ascertain further information about the reason for this state, look at the state of the OPC UA server to determine if that server is the cause of the problem, or use the Display Alarms pick action to display the subscription’s Alarms List. This state only appears with a multiple OPC UA server subscription configuration.
• 'n' Healthy—The subscription has been successfully added to 'n' OPC UA servers. The subscription is inactive in the remaining OPC UA servers. This state only appears with a multiple OPC UA server subscription configuration.
• 'n' Failed—For 'n' OPC UA servers, Geo SCADA Expert has either not been successful in connecting to the subscription's OPC UA server or the subscription was not successfully added to that server. The subscription is inactive in the remaining OPC UA servers. To ascertain further information about the reason for this state, look at the state of the OPC UA server to determine if that server is the cause of the problem, or use the Display Alarms pick action to display the subscription’s Alarms List. This state only appears with a multiple OPC UA server subscription configuration.
• 'x' Healthy, 'y' Failed—The subscription has been successfully added to 'x' OPC UA servers. For 'y' OPC UA servers, Geo SCADA Expert has either not been successful in connecting to the subscription's OPC UA server or the subscription was not successfully added to that server. The subscription is inactive in any remaining OPC UA servers. This state only appears with a multiple OPC UA server subscription configuration.