Master Control and Active/Passive Mode

The LEC Server instance, configured as an IFE, hosts a Master Control variable that toggles the instance between Active and Passive modes. A remote OPC UA client can write to this Master Control variable. In this scenario, the remote OPC UA client is one of the application’s OPC UA clients. Writing 1 to a Master Control variable sets the LEC Server instance to Active mode, while writing 0 to a Master Control variable sets it to Passive mode. A remote OPC UA client can also read the Master Control variable to query the instance’s active/passive status. It is useful for the OPC UA client to read the Master Control variable because, even though the OPC UA client knows what Master Control values it has sent, the Master Control variable may be changed by the Heartbeat mechanism or by a cluster controller.

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Master Control

The Master Control variable is available to read from and write to through the LEC Server instance’s OPC UA server using the following points:

Read Point Write Point

MasterControlOutFor<agent>

Where <agent> is the name of the actual OPC UA server agent node.

For example: MasterControlOutForAgentS

MasterControlInFor<agent>

Where <agent> is the name of the actual OPC UA server agent node.

For example: MasterControlInForAgentS

Note: You can configure the OPC UA namespace and branch for each of these points.

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Active Mode

In Active mode, LEC Server will allow the enabling of ICCP associations and OPC UA client outbound connections. However, you must enable each ICCP association explicitly with the VCC’s Association Control variable. Similarly, you must enable each OPC UA client outbound connection by explicitly setting the VMD’s Association Control variable.

Passive Mode

In Passive mode, LEC Server will disable all ICCP associations and OPC UA client outbound connections.

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Association Control Variables

Each ICCP VCC has an Association Control variable to enable or disable its associations. Writing 1 to the Association Control variable enables the VCC’s associations, while writing 0 to the Association Control variable disables the VCC’s associations. The LEC Server instance must be in Active mode for associations to be enabled; writing 1 to the Association Control variable has no effect when the instance is in Passive mode.

The name of the connected remote peer VCC is also read via OPC UA server variable.

Association Control variables are available to read from and write to through the LEC Server instance’s OPC UA server. The inbound Association Control variables for reading and writing are as follows:

Inbound Association Variables

Inbound Association: Read Point

<VCC>/AssocInCtrlStatus

Where <VCC> is a placeholder for the actual character string used in naming the VCC containing this point.

For example: AppTestVcc/AssocInCtrlStatus

Inbound Association: Write Point

<VCC>/AssocInCtrlControl

For example: AppTestVcc/AssocInCtrlControl

Inbound Connected Peer: Read Point

<VCC>/InboundPeerName

For example: AppTestVcc/InboundPeerName
Outbound Association Variables

Outbound Association: Read Point

<VCC>/AssocOutCtrlStatus

Where <VCC> is a placeholder for the actual character string used in naming the VCC containing this point .

For example: AppTestVcc/AssocOutCtrlStatus

Outbound Association: Write Point

<VCC>/AssocOutCtrlControl

For example: AppTestVcc/AssocOutCtrlControl

Outbound Connected Peer: Read Point

The outbound Association Control variables for reading and writing are as follows:

<VCC>/OutboundPeerName

For example: AppTestVcc/OutboundPeerName

 

Note: You can configure the OPC UA namespace and branch for each of these points.

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