Analytics Builder 10.16.0 | Using Analytics Builder for Cumulocity IoT | Wires and Blocks | Keys for identifying a series of events
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.