An automated assay-fluid dispensing system includes a database that associates assay protocols with assay procedures, the procedures including a first assay procedure specifying dissimilar first and second channel procedures for driving first and second channels of a fluid-dispenser cassette. The system includes a controller with a procedure selector to select or to assist a human to select an assay procedure from the database to be executed in an assay run. The controller also includes a cassette driver to drive the cassette to dispense fluids automatically to multiple sites during the assay run so that fluids in the first and second channels are dispensed in accordance with the dissimilar first and second channel procedures. The system includes a cassette interface to engage the cassette so that the controller can drive it to implement the assay run.