Queuing Of Process Data Updates - ABB COM600 series User Manual

3.12.
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COM600 series, version 4.1
User's Manual
server. The diagnostic data can be further used on COM600 HMI and gateway applica-
tions. See 6.9, Installing and configuring Duo Driver for installation and configuration
details.
Switch Fault Tolerance
The Switch Fault Tolerance feature of the Intel network adapter requires the Teaming
Feature to be enabled.
Teaming Features include Failover protection, increased bandwidth through aggregation,
and balancing of traffic among team members. Teaming Modes are AFT, SFT, ALB,
RLB, and EtherChannel*/3ad (LA/FEC/GEC/3ad). Only Failover protection using SFT
is supported by COM600.

Queuing of Process Data Updates

This section describes the common queue mechanism for OPC Clients (slave protocols)
in COM600. There can be additional queuing mechanisms on different levels of the
protocol stacks, that are specific for the protocol, which are not described here.
Process data updates are queued in the OPC Clients of COM600. Each OPC Client has
its own queues independent from other clients, which prevents disturbances on one client
connection from interfering with other connections. There are four separate queues for
different type of data with configurable length.
• High Priority
• command replies/confirms
• internal protocol stack control commands
• protocol stack database initialization commands
• State Indications
• binary data and other state indications
•
Measurements
•
analog data
•
Interrogated
• interrogation-related data and commands
Queue logic
For high priority and interrogated queues the oldest message is skipped when the queues
fill up. Generally these queues should never fill up since they contain a limited number
of updates (proportional to the number of OPC items).
When the state indication queue is full, the new updates are always skipped until there
is free space in the queue.
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