Configuring a Connection to an LEC Instance
Flex SCADA communicates to devices in the field through an LEC Front End Processor. For one FEP, there may actually be multiple LEC instances for redundancy purposes, and, at any point in time, one will be active while the others are in standby.
A FEP object in Flex SCADA is used to represent the LEC FEP and its redundant instances. Each instance is modeled as a connection in the FEP's connection list. Therefore, if an LEC FEP consists of three LEC instances, then the FEP in Flex SCADA will have three FEP connections configured. NMS will only connect to one of the LEC instances at a time. The connected instance is deemed to be active while the others are in standby; Flex SCADA will attempt to connect to each instance in turn starting with the lowest order connection until a successful connection is established. If Flex SCADA reaches the end of the connection list without obtaining a connection, it will return to the first connection and start again. If a connection is not established within the configured period (see SRS rule scadaFepDisconectPeriod), then the FEP is marked as failed, but Flex SCADA will continue to attempt to obtain a valid connection.
To view the FEP and connection list in NMS open the SCADA Status tool and select the FEP in the tree view. Right click the FEP, and select View Details....
The FEP details contains two sections:
• FEP Configuration
• Connection List
The FEP Configuration section contains configuration options that are common to all the instances of LEC:
• Control: Whether this FEP is enabled or not. Flex SCADA will only attempt to connect to LEC if the FEP is enabled.
• Status: The status of the FEP. Disabled, Enabled or Failed.
• Keep Alive: The LEC keep-alive interval (in milliseconds) used to monitor the health of a connection between Flex SCADA and LEC.
• Retry Interval: The connection retry interval (in milliseconds) controlling the time between connection attempts to the LEC instances.
The Connection List contains an entry for each LEC instance with the following properties:
• Control: Whether this LEC instance is enabled or not. If the connection is disabled Flex SCADA will not attempt to connect to the instance.
• Order: The connection order of the instance.
• IP Address: The IP Address of the LEC instance.
• Port: The IP port number of the LEC instance.