To add a floating point array item to historical data, you cannot browse to the level of the array item. The parameter field path needs to be manually edited to include the array item, using the following format:
ArrayParameterName[row,col].field
Example
FP_ARRAY[2,1].CV
The item will be added to the History Collection list as FP_ARRAY[2,1].CV. However, when downloaded to the DeltaV Continuous Historian, the parameter is specified as FP_ARRAY[2][1].CV. When downloaded to the Advanced Continuous Historian or PI Server, the parameter is specified as FP_ARRAY(2)(1).CV, because these historians do not support the use of brackets.
These syntax distinctions are important when you are configuring a Process History View trend for the array parameter. When configuring a pen in Process History View for the DeltaV Continuous Historian, use brackets to specify the array parameter path as Module/ArrayParameterName[row][col]. When configuring a pen in Process History View for the Advanced Continuous Historian or PI Server, use parentheses to specify the array parameter path as Module/ArrayParameterName(row)(col).