Abstract: A controller system having a half-duplex serial line as a bus for transferring commands, status and data between all controllers in a planting and spraying system. A bus master connected to the serial line synchronizes each controller to the network while a base console coordinates the operation of each planting and spraying system. Separate system controllers operate in conjunction with each system accessory module to control the components of each planting and spraying system. Operation of a spray control module is controlled by the sprayer control console, operating in conjunction with a base console. A planter monitor module provides control over a plurality of components in a seed-planting system. A base console with a primary user interface and a planter controller console with a planter user interface are connected to the planter monitor module over a communications medium.