Industrial alarm systems provide logging and alerting to various unforeseen situations in the manufacturing process, machinery and equipment. They are often part of the control and monitoring systems to assess and manage values of the process variables. If there is a deviation of one or more values of the process variables from the desired “normal” state, then this state is evaluated as “alarm” and highlighted in some way, eg. colour or flashing at a glance the status of alarm sources.
There are two basic types of alarms: static and dynamic. Static alarms have two states – active / inactive. Dynamic alarm uses two variables – a source of alarm variable and source of acknowledgment. The confirmation (acknowledgment) usually ensures a human operator. He confirms the information about the alarm situation. A pair of variables provides four possible states of the alarm entity: inactive, active, acknowledged and gone (resolved). To the state acknowledged the alarm entity gets if the operator or any downstream device confirms that the alarm situation is known.
OpcDbGateway can be used not only as a control and monitoring system but also as an alarm system. It even offers two alarm systems – (1) according to the OPC Foundation standard – OPC AE and (2) a proprietary alarm system, which provides several advantages which you can inquire in the document Alarms in OpcDbGateway.
In an earlier post – Mapping database tables in OpcDbGateway , it was explained how the variables from different devices and data sources are mapped to memory operands. They can be used in the proprietary alarm system as alarm sources and acknowledgment sources. Since configurable functionality OpcDbGateway enables numerous functions exercised over the memory operands, the proprietary alarm system in OpcDbGateway is extremely flexible.