Abstract: A stand-alone monitoring apparatus is provided for monitoring a plurality of selectable functions of an agricultural planter. The planter includes a plurality of seed sensors, each associated with a corresponding seed dispensing unit and generating a seed signal representative of the depositing of a seed by the associated seed dispensing unit. The monitoring apparatus includes memory for cumulatively storing population data. The population data includes a cumulative count of seeds dispensed by each dispensing unit, and a cumulative count of seeds dispensed by all the dispensing units. A microprocessor simultaneously receives seed signals from selected seed sensors, asynchronously accumulates and updates the cumulative counts associated with the selected seed sensors, and asynchronously stores the updated cumulative counts in the memory. The monitoring apparatus is intended to monitor signals from up to 16 seed sensors.