Keys for identifying a series of events
Input and output blocks identify a series of events by specifying a key for the series (or stream) of events. This series of events is used to identify correct events to deliver to an input block. The key is made up of multiple block parameters, and identifies that series of events distinct from other series of events through the same block type. For example:
For
Measurement object input and outputs, the key is the device, the fragment, and the series. The
Unit parameter specified in an output block is not considered part of the key (it is for information only) and is not required to match the parameters of the
Measurement Input block.
For
Event objects, the key is the device and the event type.
For
Alarm objects, the key is the device and the alarm type.
Restrictions for output blocks
In
Analytics Builder, for synchronous output types such as measurements, events and alarms (see also
Output blocks and event timing), it is not allowed to have more than one output block which generates events with any given key.
As there can be connections between the models, the main reason for this restriction is to avoid ambiguities or errors that may occur while processing events in the input blocks if there are multiple output blocks (in different models) generating the same output stream at the same point in time.