Custom Pictures with Logical and Physical Node Names

You can use either the logical or physical node name in displays to access data. You will only be able to write on the active SCADA. This section explains the impact of using one or the other and uses the iFIX WorkSpace as an example. This also applies to VBA scripts and any application that uses EDA (Easy Data Access) to access process data. For more information, refer to the Writing Scripts manual.

Pictures with links to tagnames using the logical node name always display data from the active SCADA, regardless of whether it is the primary or secondary SCADA. This is done without requiring the picture to be opened, closed, or replaced after failover.

If you want to access data from a specific SCADA Server using the physical node name (and have a session established to it), you can read data from both the primary and secondary SCADA, regardless of which one is active, but you can only write to the SCADA that is active. You cannot write to the SCADA that is in standby mode. This is because you used the physical node name in the datalink. The picture displays data from the physical SCADA Server specified. If communication with that SCADA Server is lost, data for datalinks using the physical node name is not available at the iClient until the connection is re-established with that node.

For example, if the datalink on the iClient node is using the logical node name of the SCADA pair (for example LNN.DI_VALVE_OPEN.F_CV) and it is currently getting data from the primary SCADA (which is the active SCADA) and a failover to the standby SCADA occurs, then the datalink still displays data that is from the now active secondary SCADA.

However, if the datalink the iClient node is using the physical node name of the primary SCADA pair (for example FOXBORO.DI_VALVE_OPEN.F_CV) and is currently getting data from the primary SCADA (which is the active SCADA) and a failover to standby SCADA occurs, then the datalink displays @@@@ and a 1914 “Connection not established” prompt displays.