Alarm Server Runtime

The Alarm server has the following runtime operations that are described in more detail in the sections of this topic. They are:

Startup
OPC Alarm and Events Interface
OPC Data Access Interface
Error Reporting

Starting the Alarm Server

The AlarmWorX64 Server may be launched in one of the following ways:

Automatically on boot if it is installed as a service. For more information, refer to AlarmWorX64 Server Service.
By selecting Start AlarmWorX64 Server from the Action menu of the AlarmWorX64 Server Configurator.
When an OPC Alarm and Events client creates a connection to the alarm server. Note, however, that the server should normally be running and processing alarms even if no alarm clients are active.

When launched, AlarmWorX64 Server opens the active configuration database and queries for a configuration that is set to run on that node. If a configuration with a matching node name is not found, the default alarm configuration will be run. While running, the server will continue to poll the configuration database (every 30 seconds) in order to respond to any changes made by the Configurator.

AlarmWorX64 Server supports online configuration changes to allow minor changes in alarm configuration to be performed without shutting down the server. Minor changes include adding or removing a tag, changing an alarm limit, and adding (but not removing) an area. Making even these minor changes online can have side effects, like duplicate events sent to clients and client messages that can no longer be acknowledged. In a live, functioning plant it is possible that these minor side effects would not outweigh the alternative of shutting down and restarting the alarm server.

Whenever practical, toggle the server off and on to be sure only the latest configuration is being used. For major database changes within the active database or changing the active database, the server must be shut down and restarted.

OPC Alarm and Events Interface

The AlarmWorX64 Server supports all of the mandatory and most of the optional interfaces and methods of the OPC Alarm & Events specification.

The following optional methods are not currently supported:

IOPCEventServer::
IOPCEventServer::
IOPCEventServer::
IOPCEventServer::
IOPCEventServer::

Alarm Categories

All events generated are of the OPC-defined Event Type Condition. TheServer defines the following Event Categories and uses the identical names for the Condition Names:

Deviation: Triggers an alarm if the difference between two input values exceeds the high or low limits specified in the AlarmWorX64 Server configuration.
Digital: Triggers an alarm if the comparison between the Alarm State Value (specified in the AlarmWorX64 Server configuration) and the input state is TRUE.
Limit: Triggers an alarm if the input value exceeds the high or low limits specified in the AlarmWorX64 Server configuration.
Rate of Change: Triggers an alarm if an input value changes at a rate greater than or equal to the limit specified in the AlarmWorX64 Server configuration.

The Limit and Deviation conditions have the following subconditions:

HiHi: Triggers an alarm if the value is greater than or equal to the HiHi limit specified in theconfiguration.
Hi: Triggers an alarm if the value is greater than or equal to the Hi limit specified in the AlarmWorX64 Server configuration.
Lo: Triggers an alarm if the value is less than or equal to the Lo limit specified in the AlarmWorX64 Server configuration.
LoLo: Triggers an alarm if the value is less than or equal to the LoLo limit specified in theconfiguration.

The following categories are NOT used in the AlarmWorX64 Server :

OPC Server Error
System Configuration
System Message

Event Server Categories

The GenEvent Server defines the following Event Categories:

Operator Process Change: Sent by GenEvent when a value is changed in GraphWorX64 .
Sysconfig: Sent by GenEvent when a configuration change is made to a file or database.
System: All other GenEvent messages.