An analytic system comprising a plurality of asset models for modeling a plurality of assets to be monitored at remote sites (4a, 4b) using a plurality of sensors using different original units of measurement, the plurality of asset models comprising an expression for a calculation for the plurality of assets; a memory comprising computer instructions; and a processor coupled to the memory, wherein, when executing the computer instructions, the processor effectuates operations to perform analytics on the plurality of asset models. The operations comprise for each of the plurality of assets: retrieving the expression and one or more arguments for a calculation of an asset model of the plurality of asset models, the asset model representing an asset at a remote site; attaching time-series parameters associated with the asset and sensed by a sensor at a remote site, the time-series parameters being attached as required to the arguments, wherein the time-series parameters are specified by one or more tags, wherein a tag is the primary key identifier used to uniquely identify each time-series parameter; wherein the analytic system comprises a tag pattern that matches tags appearing in the modeling of different assets of the plurality of assets; retrieving time-series data based on the attaching step; converting the time-series data from an original unit associated with the time-series data to a standard unit; performing a calculation based on the expression and the converted time-series data to achieve a result, wherein performing the calculation comprises using the tag pattern in a calculation in which there are differences in configuration of the plurality of assets; converting the result to the original unit; and writing the result to a tag associated with the one or more arguments, wherein writing the result to the tag is performed by writing the result to the tag using the original unit; the analytic system being configured to remotely monitor the plurality of assets based on the performed analytics.