Maximum number of rows depends on PROMOTIC Runtime licence and is: PmRtProf: 65535, PmRtFree: 30 and PmRtXX: XX (for example PmRt100: 100).
The value of this property can be also obtained in the "PmaRoot" item of the INFO system (when looking into the object with this property).
var oDataTable = pMe.Pm("/DataTable");
var nRows = oDataTable.Rows;