1. Any properties which have been explicitly specified by the use of a parameter. If an input is a pulse, it is treated as an object using the properties of that input. If an input has a primary value (not a pulse), then the primary value is used. To use the properties instead, use the Extract Property block with the Property Path parameter not set and the Property Type parameter set to Properties which replaces the primary value with a pulse (which is ignored) and the properties are used.

2. The properties of any Value object on an input port which does not have the corresponding parameter set. This is a straight merge of the properties dictionary. If two dictionaries have the same property key, then the input port with the lowest identifier has precedence. Thus any shared properties on Input 1 overwrite properties from Input 2 and down.

3. Any properties on a Value object provided to the Merge input port are kept if they are not overwritten by either of the operations above. The optional Merge input port allows chaining or supplementing a set of properties from another block.